Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02354172 2001-08-08
OPTICAL CONNECTOR
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to an optical connector
for connecting optical fibers, and more specifically to an
optical fiber connector preferably applicable to a plug-in
optical connector for removably connecting a number of
package boards (on each of which various optical and
electrical components or parts are mounted as a completed
part subassembly) to a back panel perpendicular to the
package board in book-shelf fashion to construct a
high-density assembly unit.
Description of Prior Art
With the progress of higher optical performance in
optical communication systems, a higher density assembly
unit composed of so-called plug-in connectors is required
more and more.
In the plug-in optical connector, it is required that
a number of optical fibers must be simultaneously coupled
to or decoupled from each other by a simple insertion and
removal coupling operation. Further, since a number of
optical fibers are coupled to each other under pressure
within the connector housings, a certain connector housing
locking mechanism is required to prevent the ferrule
coupling pressure from being directly applied to the
package board and the back panel via the connector
housings.
Further, in an optical assembly unit, since a number
of backage boards are connected to a back panel via plug-in
connectors in book-self arrangement fashion, it is
necessary to absorb an assembly error in the direction
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perpendicular to the axial direction of the optical
connector element (plug and jack), without increasing the
dimensions or the size of the optical connector.
In addition, since a number of optical connector
elements (plug and jack) are simultaneously fitted to the
plug-in optical connector, it is also necessary to absorb
each dimensional and assembling error in the axial
direction of the plug/jack. In absorption of the axial
coupling error between the plug/jack and the connector, it
is not preferable to increase the axial connector length;
that is, it is necessary to stably support the plug/jack
within the connector housing without increasing the axial
length of the plug/jack.
Further, when an optical plug comprising a ferrule
which is connected to an end of an optical fiber is fitted
to the optical connector, a optical plug locking mechanism
including elastic cantilever arm members with a claw at the
free end thereof, are provided between the optical plug and
the optical connector housing. However, since the locking
mechanism is reduced in size more and more with increasing
fiber arrangement density, it is necessary to more firmly
lock the connector plug to the connector housing, even when
a high tensile strength is applied to the optical fiber, in
spite of a simple insertion and removal operation.
Further, when the optical plug is inserted into the
optical connector, it is particularly preferable that the
optical plug is easily fitted to the connector housing in a
predetermined orientation to eliminate an axis alignment
error between two mated optical ferrules in order to
maintain high optical signal transmission characteristics.
Further, when an optical jack comprising a ferrule
which is connected to an end of an optical fiber and an ,
alignment sleeve is fitted to the optical connector, it is
preferable that the ferrule end can be easily cleaned and
further the ferrule alignment sleeve can be easily replaced
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with a new one, because the wear chip is produced within
the ferrule alignment sleeve whenever the optical jack is
coupled to or decoupled from the connector housing.
The structure and arrangement of the prior-art optical
connector, plug, jack etc. will be described in more detail
hereinafter with reference to the attached drawings under
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS.
SUMMARY OF THE INVENTION
With these problems in mind, therefore, it is the
primary object of the present invention to provide an
optical connector which can be locked and unlocked by
simple insertion and removal coupling operation to connect
two mated optical fibers under pressure, without directly
applying the ferrule coupling pressure to the package board
and the back panel, while absorbing the optical connector
element coupling error along the axial direction thereof.
It is the second object of the present invention to
provide an optical connector which can absorb an assembly
error in the direction perpendicular to the ferrule axial
direction, without increasing the connector housing size.
It is the third object of the present invention to
provide an optical connector which can slidably and stably
support the optical connector element (ferrule) within the
connector housing without increasing the axial length of
the ferrule.
It is the fourth object of the present invention to
provide an optical connector by which an optical plug can
be firmly locked to the connector housing even when a high
tensile force is applied to the optical fiber.
It is the fifth object of the present invention to
provide an optical connector by which the optical plug can
be always fitted to the connector housing in a
predetermined orientation to eliminate an axis alignment
mismatching between two mated optical ferrules.
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It is the sixth object of the present invention to
provide an optical connector ,having an optical jack whose
ferrule can be easily cleaned and whose ferrule alignment
sleeve can be easily replaced with a new one.
To achieve the above-mentioned first object, the
optical connector according to the present invention
comprises: (a) a first housing (33) for supporting at
least one first optical plug or jack; (b) a second housing
(34) coupled to said first housing; (c) a third housing
(36) slidably coupled to and within said second housing
(34) and also coupled to first housing (33), for supporting
at least one second optical ferrule connected to said first
optical ferrule; (d) first engage means (37, 38) provided
between said second and third housings, for engaging said
third housing with said second housing when said third
housing is not coupled to said first housing; (e) second
engage means (39, 40) provided between said first and third
housings, for engaging said third housing with said first
housing when said first housing is coupled to said second
and third housings; (f) first release means (41) provided
for said first housing, for releasing said first engage
means when said third housing is being engaged to said
first housing by means of said second engage means; and (g)
second release means (42) provided for said second housing,
for releasing said second engage means when said second
housing is being coupled to said third housing, and said
first housing is being decoupled from said second third
housings. The first engage means comprises a first
projection (37) formed in said second housing and a first
elastic lever (38) formed in said third housing; and said
first release means comprises a release member (41) for
deforming said first elastic lever in a direction
perpendicular to an axial direction of the plug and jack.
The second engage means comprises a second projection (39)
formed in said third housing and a second elastic lever
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(40) formed in said first housing, and said second release
means comprises a release member (42) for deforming said
second elastic lever in a direction perpendicular to an
axial direction of the plug and jack. The first projection
(37) is formed with a first projection engage surface (37b)
and a first projection inclined surface (37a), said first
elastic lever (38) is f armed with a first lever claw (38a)
engageable with said first projection engage surface (37b)
and a first lever side projection (38a), and said first
release member (41) is formed with a first release member
inclined surface (41a) engageable with the first lever side
projection (38a); when said second housing is coupled to
said first housing, said first release member inclined
surface (41a) is brought into contact with said first lever
side projection (38a) to deform said first elastic lever
(38) so that said third housing is decoupled from said
second housing to allow said third housing to be axially
slidable within said second housing; and when said second
housing is decoupled from said first housing, said first
projection inclined surface (37a) is brought into contact
with said first lever claw (38b) to deform said first
elastic lever (38) so that said third housing is coupled
with said second housing. The second elastic lever (40) is
formed with a second lever claw (40a) engageable with said
second projection (39) and a second lever side projection
(40b), and said second release member (42) is formed with a
second release member first inclined surface (42c) and a
second release member second inclined surface (42a); when
said second housing is coupled to said first housing, said
second release member first inclined surface (42c) is
brought into contact with said second lever side projection
(40b) to deform said second elastic lever so that said
second housing is coupled to said f.i.rst housing; and when
said second housing is decoupled from said first housing,
sa.i.d second release member second inc.l.i.ned surface (42a) is
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brought into contact with said second lever side projection
(40b) to deform said second elastic lever so that said
second housing is decoupled from said first housing.
Further, it is preferable that at least two said first
engage means (37, 38), at least two said second engage
means (39, 40), at least two said first release means (41),
and at least two said second release means (42) are
arranged in symmetry with respect to outer side surfaces of
a connector housing of a plug-in optical connector in which
a number of optical plugs and jacks arranged in a line can
be connected simultaneously.
In the optical connector according to the present
invention, the optical connector housing mounted on package
can be engaged with and disengaged from the optical
connector housing mounted on back panel of unit frame by
only inserting and removing the elements into and from the
unit frame; the connector itself is provided with a Iock
mechanism; and no specific precision is required with
respect to the engagement position along the axial
direction of the optical connector elements. Therefore,
since the optical elements on the package side housing can
be connected to the optical elements on the back panel side
housing located deep into the unit frame by only inserting
and removing the package board into and from the back
panel, after the optical connector has been connected, no
resiliency of the optical connector elements will be
directly applied to the back panel in the case of the
plug-in. optical connector according to the present
invention.
The functions of the optical connector according to
the present invention will be summarized as follows:
In engagement, when the second connector comprising
the second and third housings is coupled to the first
connector comprising the first housing,
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(1) the second connector is coupled to the first
connector in condition that the second housing and the
third housing are kept engaged,
(2) the first optical connector elements are
connected to the second optical connector elements,
(3) the first housing of the first connector is
engaged with the third housing of the second connector,
(4) the third housing is disengaged from the second
housing, and
(5) further the dimensional error in the insertion
direction can be absorbed by inserting the second housing.
In disengagement, when the second connector is removed
from the first connector,
(1) the third housing is moved with the first
housing,
(2) the second housing is engaged with the third
housing,
(3) the third housing is disengaged from the first
housing,
(4) the first optical connector elements are
disconnected from the second optical connector elements,
and
(5) the second connector is removed from the first
connector.
To achieve the above-mentioned second object, the
optical connector further comprises: plug-in connector
housing floating means provided on one side surface of the
connector housing in contact with a back panel or a package
board (125) on which various optical and electrical parts
are mounted as a subassembly unit. The floating means
comprises: (a) a slot (133) formed with the back panel or
package board in such a way that the slot extends in the
direction perpendicular to the axial direction of the
optical plug (35) or jack (124); (b) an axle member (127)
fixed to said connector housing and slidably fitted into
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the said slot; and (c) a reverse side housing or a nut
member ( 128 ) fixed to an end of said axle member so as to
loosely sandwich the back panel or package board between
said axle and a reverse side housing or nut members.
According to the present invention, it is possible to
realize a simple and precious floating structure such that
slot members formed with a float slot are fitted to
through-holes formed in the package board; the float axle
members of the housing are inserted into the float slots;
and the nut members are fixed to the end of the float axle
members. In this case, the floating condition can be
controlled by a clearance between the float axle members
and the slots of the slot members.
To achieve the above-mentioned third object, the
optical connector further comprises an optical connector
plug including: (a) a plug housing (202) formed with a
shoulder portion (253) between a large hollow portion (254)
and a small hollow portion (252) and formed no projection
between said two portions; (b) a plug ferrule (201)
connected to .an optical fiber (204) and formed with a
flange portion (201b) slidably fitted into the large hollow
portion of said plug housing and an end portion (201a)
passed through the small hollow portion of said plug
housing; and (c) a spring (203) housed within said plug
housing to urge the flange portion of said plug ferrule
against the shoulder portion (253) of said plug housing. A
mated jack ferrule (201) is fitted to the small hollow
portion (252) of said plug housing (202) via a sleeve
holder (206) having a floating slit sleeve (205)
therewithin so as to absorb an axial dimensional fitting
error between the plug ferrule and the jack ferrule by
axially urging the flange portion (201b) of said plug
ferrule by an inner end of the sleeve holder (206) against
said spring (203).
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According to the present invention, the ferrule is
supported within the plug housing, and urged in the axial
direction by the spring. When the sleeve holder is
inserted from the ferrule support side into the plug
housing, the sleeve holder is brought into contact with the
flange portion of the ferrule passing through the shoulder
portion against the urging force of the spring, so that the
ferrule can be inserted deep further from the initial
position to absorb the axial positional error.
To achieve the above-mentioned fourth object, each of
said first and third housing (352) further comprises an
elastic lever arm (357) axially extending forward and
inwardly and having a claw (358) formed with an insertion
inclined surface, an engage surface, and a side projection
at a free end thereof, and the optical connector further
comprises: (a) a plug housing (359) connected to an end
of an optical fiber (361) and coupled to said housing, said
plug housing having an outer engage projection
(360); and (b) a knob block (362) slidably fitted between
said housing and said plug housing, said knob block having
an outer release projection (364) formed with an engage
inclined surface and a release inclined surface. When said
plug housing (359) is coupled to said housing (352), the
engage inclined surface of the outer release projection
(364) of said knob block (362) is brought into contact with
said side projection of .,said inner elastic lever arm (357)
of said first or third housing (352) to outwardly deform
said inner lever arm so that said outer engage projection
( 3G0 ) i.s c~ng~gcd w.i. th Lhc cng~~gc ~ur f'acn ~f :~a i d i nner
elastic arm (357); when said plug housing (359) is
decoupled from said first or third housing (352), the
release inclined surface of the outer release projection
(364) is brought into contact with the side projection of
said inner elastic lever arm (357) to outwardly deform said
inner lever arm so that said inner elastic arm is
disengaged from said engage projection (360).
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In the optical connector according to the present
invention, when the optical plug is inserted into the
connector housing, since the, engage projections of the
optical plug are brought into contact with the claws of the
elastic arms provided for the connector housing to deform
the elastic arms, the engage surfaces of the engage
projections are engaged with the engage surfaces of the
claws.
Under these conditions if the optical cord of the
optical plug is pulled, although the force is transmitted
to the claws via the engage projections, since the point of
force application is offset from the base portion of the
elastic arm relative to the connector housing, a moment is
generated around the elastic arm in such a direction that
the elastic arm end goes toward the optical plug side about
the fixed end of the elastic arm. As a result, when a
tensile force is applied to the optical cord in the
direction that the optical plug is separated from the plug
adapter, since the elastic arm end moves toward the optical
plug side, the engage surface of the claw is further urged
toward the engage surface of the engage projection, thus
resulting in secure engagement conditions. On the other
hand, when the optical plug is removed from the connector
housing: that is when the knob block is gripped and the
optical plug is pulled away from the connector housing,
since the engage release projections of the blocks push
upward the engage release side projections of the elastic
arms of the connector housing, the elastic arms are
deformed in the direction that the engage projections are
removed from the claws. Therefore, when the optical cord
is pulled; the optical plug can be removed from the
connector housing.
To achieve the above-mentioned fifth object, said
first or third housing (416) formed with at least one
housing cutout (425) and at least two opposing housing
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projections (424), and the optical connector further
comprises a square cross-section optical. connecto r plug
(411) formed with an axially extending plug projection
(419) on one side surface thereof so as to be engaged with
the housing cutout (425) and with two axially extending
plug grooves (418) on two opposing side surfaces thereof so
as to be engaged with the two opposing housing projections
(424), an outside contour of said square optical connector
plug being symmetrical with respect to a plane including an
axial center of said connector plug and a middle portion of
the plug projection but asymmetrical with respect to the
axial center of said connector plug.
In the optical connector according to the present
invention, when optical connector plugs are mounted on the
connector housing at the highest possible mounting density,
since the two opposing side surfaces are symmetrical with
respect to a central plane parallel to the two opposing
side surfaces but asymmetrical with respect to a central
axis of the two opposing side surfaces, it is possible to
prevent the optical connector plug from being inserted into
the insertion hole of the connector housing in the
erroneous mismatching direction opposite to the
predetermined direction, thus securing a correct insertion
of the plug into the housing at all times.
'1.'o achieve the pbovc--mcnti.oncd Sixth object, the
optical connector further comprises an optical connector
jack (501) having: (a) a rear housing (521) fitted to
said connector housing; (b) a front housing (522)
removably engaged with said rear housing; (c) an alignment
sleeve (504) fixedly fitted into said front housing; (d) a
ferrule (503) connected to an end of an optical fiber and
fitted into said alignment sleeve so that a front end
thereof extends frontward from the engagement position
between said rear and front housings. 'fhe front and rear
housings are removably engaged with each other via thread
or friction.
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In the connector ;jack according to the present
invention, the front and rear housings can be removed
easily by loosening the thread or releasing them against
frictional force. Since the front housing is removed, the
alignment sleeve in the front housing is easily removed
from the jack for replacement with a new one. Further,
after removal of the front housing, since the ferrule end
surface projects from the rear housing, the ferrule end
surface can be cleaned easily.
In the optical connector according to the present
invention, although various features have been explained of
the optical connector composed of two connector housings.
Without being limited thereto, however, it is also possible
to apply the features of the present invention to the
optical adapter for connecting a single optical plug and
jack.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1(a) is a perspective view showing prior-art
plug-in optical connectors arranged in book-self
arrangement fashion into an assembly unit for assistance in
rr.Pl~,inin~7 I: he function thereof;
Fig. 1(b) is a perspective, partially broken view
showing a prior-art push-pull optical connector using an
adapter;
Figs. 2 to 3 show a first embodiment of the optical
connector according to the present invention for assistance
in explaining the first feature thereof;
Fig. 2 is a partially broken, perspective view of the
optical connector;
Figs. 3(a) to'3(j) are side cross-sectional views for
assistance in explaining the engagement and disengagement
steps of the optical connector shown in Fig. 2;
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Figs. 4 and 5 show a second embodiment of the optical
connector according to the second embodiment, in which the
number and the location of the engage means and the release
means are modified so as to be applicable to a plug-in
connecto r
Fig. 4 is a plan, partially broken view thereof;
Fig. 5 is a side, partially broken view thereof;
Figs. 6 and 7 are plan views showing prior-art
floating structure of the plug-in connector;
Figs. 8 to 11 show an embodiment of the floating
structure of the plug-in connector according to the present
invention for assistance in explaining the second feature
thereof;
Figs. 8(a) and 8(b) are partially cross-sectional,
plan and side view thereof;
Figs. 9(a) and 9(b) are enlarged cross-sectional views
taken along the lines II-II and III-III i.n Fig. 8(a),
respectively;
Fig. 10(a) is an enlarged plan view showing a slot
member Lixed to a package board;
Fig. 10(b) is an enlarged view showing the axle member
fitted to the slot member;
Fig. 11 is an exploded view showing the essential
portions of the floating structure for assistance in
explaining the method for assembly;
Fig. 12 is a perspective, partially broken view
showing a prior-art optical connector connected via an
adapter;
Figs. 13(a) to 13(c) are side cross-sectional views
for assistance in explaining the engagement positional
relationship between the plug and the sleeve holder when a
prior-art optical connector is applied to the plug-in
optical connector;
Fig. 14(a) is a front view showing a prior-art
ferrule;
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Fig. 14(b) is a side view showing the same prior-art
ferrule;
Figs. 15 to 17 are views for assistance in explaining
the third features of the present invention;
Fig. 15(a) is a cross-sectional view showing an
embodiment of the optical connector plug according to the
present invention;
Fig. l5(b) is a cross-sectional view taken along the
line A-A in Fig. 1(a);
Fig. 15(c) is a cross-sectional view taken along the
line B-B;
Figs. 16(a) and 16(b) are cross-sectional views for
assistance in explaining the engagement relationship
between the optical connector plug and the sleeve holder;
Fig. 17(a) is a front view showing the ferrule;
1''ig. 17(b) is a side view showing the ferrule;
Fig. 18 i.s a pricipal illustration showing the
en~a~cmonl: relationship of the prior-art optical connector;
Figs. 19 to 24 are views for assistance in explaining
the fourth feature of the present invention;
Fig. 19 is a partially broken, cross-sectional view
showing an embodiment in which the optical connector
according to the present invention is applied to a
push-pull optical connector using an adapter;
Fig. 20 is a front view showing the optical plug
thereof;
Fig. 21 is a plan view of the same;
Fig. 22 is a left side views of the optical plug shown
in Fig. 20;
Fig. 23 is a pricipal illustration showing the
engagement relationship of the optical connector;
Fig. 24 is a partially broken, cross-sectional view
showing another embodiment in which the optical connector
according to the present invention i.s appl.ied to a plug-.in
optical connector fixed to a back panel;
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Fig. 25 is a perspective view showing a prior-art
optical connector;
Figs. 26(a) and 26(b) are front view for assistance in
explaining the states where the prior-art optical connector
plug is inserted into the connector housing;
Figs. 27 to 31 are views for assistance in explaining
the fifth feature of the present invention;
Fig. 27 is a perspective view showing an embodiment of
the optical connector according to the present invention;
Figs. 28(a) to 28(d) are illustrations for assistance
in explaining the construction of the optical connector
Fig. 28(a) is a front view showing the same;
Fig. 28(b) is a top view showing the same;
Fig. 28(c) is a side, partially cross-sectional view
showing the same;
Fig. 28(d) is a bottom view showing the same;
plug of the present invention;
Fig. 29 is a side cross-sectional view showing the
state where the optical connector plug is inserted;
Fig. 30 is a plan view showing the connector housing
of the present invention;
Figs. 31(a) and 31(b) are plan views for assistance in
explaining the states where the optical connector plug of
the present invention is inserted into the connector
housing;
Fig. 32 is a cross-sectional view showing a prior-art
plug-jack optical connector;
Figs. 33 to 38 are views for assistance in explaining
the sixth feature of the present invention;
Fig. 33(a) is a cross-sectional view showing a first
embodiment of the optical connector jack according to the
present invention;
Fig. 33(b) is a cross-sectional view showing the front
housing removed from the' rear housing of the optical
connector jack;
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Fig. 33(c) is a cross-sectional view showing the rear
housing of the optical connector jack according to the
present invention;
Fig. 34(a) is a partially broken cross-sectional view
showing a second embodiment of the optical connector jack
according to the present invention;
Fig. 34(b) is a cross-sectional view showing the front
housing;
Fig. 35 is a cross-sectional view showing a
modification of the front housing;
Fig. 36(a) is a partially broken cross-sectional view
showing the entire construction of a third embodiment of
the optical connector jack according to the present
invention;
Fig. 36(b) is a cross-sectional view showing a pair of
optical connector jack and the optical connector;
Fig. 37(a) is a cross-sectional view showing an
optical connector jack;
Fig. 37(b) is a side view showing the same optical
connector jack shown in Fig. 37(a);
Fig. 38 is a similar cross-sectional view showing the
optical connector jack shown in Fig. 37(a) from which the
front housing is removed away;
Figs. 39 to 41 are views for assistance in explaining
the first to fifth features of the optical connector
according to the present invention;
Fig. 39(a) is a left side view showing one embodiment
of the first optical connector applied to a plug-in optical
connector;
Fig. 39(b) is a front view showing the same;
Fig. 39(c) is a right side view showing the same;
1''lg. SJ(cJ) .L~ n l,u~ v.iuw ~I~c.~witn~ LI»: ~snm~_~~
Fig. 40(a) is an enlarged transversal cross-sectional
view showing the essential portions of the same optical
connector;
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Fig. 40(b) is an enlarged longitudinal cross-sectional
view showing the same optical connector;
Fig. 41(a) is a left side view showing one embodiment
of the second optical connector applied to a plug-in
optical connector;
Fig. 41(b) is a front view showing the same;
Fig. 41(c) is a right side view showing the same;
Fig. 41(d) is a top view showing the same;
Fig. 42(a) is an enlarged transversal cross-sectional
view showing the essential portions of the same optical
connector;
Fig. 42(b) is an enlarged longitudinal cross-sectional
view showing the same optical connector; arid
Fig. 43 is an illustration for assistance in
explaining the floating structure of the second connector
relative to the back panel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the optical connector according to the
present invention will be described hereinbelow in detail
with reference to the attached drawings.
The first feature of the present invention relates to
an optical connector structure for. connecting optical
fibers, and more specifically to an optical connector
applicable to a plug-in optical connector used to connect
two or more package boards on which optical or electric
parts are mounted into an assembly unit frame.
Prior to the description of the optical connector, a
reference will be made to a prior-art optical connector
with reference to the attached drawings.
To connect two optical fibers, it is necessary to use
optical connectors provided with precise engagement
mechanism. In particular, when a package board on which
various optical modules are mounted is connected to a unit
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frame and further optical signals are transmitted between
the two package boards and between the package board and an
external device, a plug-in optical connector as disclosed
in U.S. Patent for instance. No. 4,895,425 entitled
"Plug-in Optical Fiber Connector" is adopted, Fig. 1(a) is
a perspective view for assistance in explaining the usage
and the structure of the prior-art plug-in optical
connector, disclosed in this patent document.
A circuit board on which various optical/electrical
parts are mounted is fixed to a package board 1. An
optical fiber 2 of the circuit is terminated within a
ferrule inside of an optical jack (connector element) 2A
and guided into the connector housing 3 or 3A fixed to the
package board J. On the other hand, another optical fiber
7 guided from another package board or a device is
terminated within a ferrule inside of an optical plug
(connector element) 7A and guided into the connector
housing 6 and 6A fixed to a back panel 5 of a unit frame 4.
Therefore, the package board i can be engaged with or
disengaged from the back panel 5 via connectors by
inserting/removing the package board 1. For instance, when
the package board 1 is moved toward the back panel 5, the
connector housings 3 and 3A fixed to the package boards 1
are engaged with the connector housings 6 and 6A fixed to
the back panel 5 and additionally the inner optical
connector elements 7A and 2A are coupled to each other by
connection between the package board 7_ and the back panel.
5.
As described above, in the plug-in optical connector,
it is required that the optical connector elements can be
securely engaged or disengaged by only inserting or
removing the package board 1 into or from the back panel 5.
In general, after connected, two ferrules of optical
connector elements are urged toward each other by a spring,
so that a resiliency of about 1 kgf is generated between
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CA 02354172 2001-08-08
two optical connector elements. Therefore, a lock
mechanism is required for each connector element.
In the conventional plug-in optical connector,
however, no lock mechanism is generally provided for the
optical connector. This is because the position at which
the optical connector is engaged is located deep in the
unit and additionally the connector must be engaged with or
disengaged from the back panel by only inserting or
removing the package board into or from the back panel.
Instead of the lock mechanism, it is also possible to
provide a separate engage structure at the front surface of
the package board, independently from the connector, as
disclosed in Japanese Published Unexamined (Kokai) Utility
Model Appli. No. 61-109189, entitled "Package Lock
Mechanism".
This document shows a structure such that package
boards are mounted on a shelf having a plane perpendicular
to the package insertion/removal direction, in which a leaf
spring deformable in the direction perpendicular to the
package insertion/removal direction is mounted on the
package board, and a part of the leaf spring is engaged
with a plane perpendicular to the shelf.
In the prior-art package lock structure as described
above, however, since the resiliency between the optical
connector elements is directly transmitted to the back
panel or the unit frame via the connector housing, the
connector resiliency increases roughly proportionally with
increasing number of the connector elements to be
connected. Therefore, with the progress of optical
technology, the number of the connector elements per unit
tends to increase and therefore the connector resiliency
also increases, thus resulting in a problem in that a
resiliency to the back panel is large and therefore the
unit frame or the rack may be deformed. For instance, the
assumption is made that the resiliency per connector
- 19 -
CA 02354172 2001-08-08
element is 1 kgf; the number of the elements per package
board is 4; and the number of package boards per unit is
30. In this case, a force as large as 120 kgf is alway
applied to the back panel and the unit frame.
Once the unit frame and the back panel are deformed,
since the mutual connection positional relationship between
the package board and the back panel changes, there exists
a problem in that the stability in the connection
characteristics of the optical and electric connectors
deteriorate.
On the other hand, a push-pull lock (single core)
optical connector is disclosed in Electronic Communication
Transaction CS-85-128 (Published Dec. 20, 1985), in which
the optical connector itself is provided with a lock
mechanism and the connector element can be engaged with or
disengaged from the connector adaptor by only the insertion
and removal operation.
Fig. 1(b) shows a plug-in optical connector to which
the above-mentioned optical connector structure is applied.
In the drawing, an adaptor 10 is mounted on a back panel 5
and a knob 13 of a plug 12 is fixed to the package board 1.
Further, although not shown, another plug for terminating a
cable from another package board or a device is mounted on
the side (the left side) opposite to the package side of
the adaptor 10.
The plug 12 is composed of a plug housing 16 for
supporting an optical connector element (referred to as
ferrule) 15 and a knob 13. The plug housing 16 is slidable
inside the knob 13 in the axial direction of the element
15. Only when the package board 1 is inserted into the
back panel 5, an engage lever'17 of the adaptor 10 mounted
on the back panel 5 is engaged with a projection portion 18
of the housing 16 of the plug 12, so that the package plug
12 is engaged with the adaptor 10. To release the
engagement, the engage lever 17 of the adaptor 10 is
- 20 -
CA 02354172 2001-08-08
disengaged Erom the projecting portion 18 ~F the housing 16
of the plug 12 by deforming the engage lever 17 outwardly
when two projections 11 are broughr_ inr_o contact with two
side projections 17a oL the engage lever 1/, b~Core the
S package board 1 is removed Lrom l.he back panel S.
In the plug-in optical connec'or as described above,
however, there exists an essential problem as follows: To
securely engage the plug 12 with the adapter 10, it is
necessary to sufficiently insect the knob 13 of the plug 12
(i.e. the package board provided with the knob 13) into the
adapter 10 and then to remove it a little back (foward the
right).
To generate an engage force between a claw portion 20
of the engage lever 17 and the projection portion 18, an
IS engage surface 20a of the claw portion 20 must be brought
into contact with an engage surface 18a of the projection
18. However, since the position of the engage surface 20a
away from the back panel S and the position of the engage
surface 18a relative to the package board 1 are determined,
cespectively on the basis of the parts dimensions and the
parts assembly ,precision, when the above-mentioned
insertion and removal op-eration is required so that the
package board 1 is sufficiently inserted into the back
panel 5 to engage the engage lever 17 with the projection
portion 18, and thereafter removed a little backward to a
position at which an engagement force is generated due to
contact between the engage surface 20a of the claw portion
20 and the engage surface 18a of the projection portion 18,
the optical connector coupling workability i.s remarkably
reduced, because the package board 1 must be removed a
little backward at high precision.
In addition, various connectors such as package
electric connectors plural connectors of
different type, etc. are generally mounted on the same
package board and backpanel together with the optical
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CA 02354172 2001-08-08
connectors. These package connectors are usually used by
sufficiently inserting the package board into contact with
the back panel without backward removal operation.
Therefore, the afore-mentioned optical connector which
requires a little backward removal operation cannot be
mounted on the same package board 1 together with various
other connectors coupled without backward removal.
Further, when a plurality of various connectors are
mounted on the same package board, each plug-in optical
connector element is usually required to absorb a
positional coupling error of about 1 mm in the axial
direction of the optical connector element, because there
inevitably exist some production error (dispersion) in the
unit frame and the package board and some assembly error at
connector mounting position. Therefore, in the prior-art
optical connectors, there exists a problem in that it is
difficult to absorb the production and assembly errors and
additionaly to allow the optical connector to be mounted on
the same package board together with other connectors of
different types.
As described above, in the prior-art plug-in optical
connector, since the optical connector is not provided with
a connector lock mechanism, a resiliency of the optical
connector is directly applied to the package board and the
back panel, thus resulting in a problem in that the back
panel is easily deformed.
In addition, when the prior-art lock mechanism for the
optical connector is simply applied to the plug-in optical
' connector so that the optical connector elements can be
engaged with or disengaged from each other by only the
simple insertion and removal operation, there are drawbacks
such that the high connector dimension precision is
required or the connector coupling workability is
deteriorated.
- 22 -
CA 02354172 2001-08-08
The first feature of the optical connector according
to the present invention is to provide an optical
connector, in particular usable as a plug-in optical
connector by which optical connector elements can be
engaged with or disengaged from each other by simple
insertion and removal operation; the connector itself can
be locked; and no high axial-direction positional precision
is required when engaged.
An first embodiment of the present invention will be
described hereinbelow with reference to Figs. 2 and 3.
Here, it should be noted that although the optical
connector according to the present invention can be applied
to the ordinary optical connector, the plug-in optical
connector to which the present invention is applied will be
explained by way of example, because the plug-in optical
connector can make the best use of the feature of the
present invention.
Fig. 2 is a perspective, partially broken view for
assistance in explaining the optical connector housing
according to the present invention, in which the optical
connector elements are not shown. Figs. 3(a) to 3(j) are
cross-sectional views for assistance in explaining the
engagement steps of the connector.
The connector of the present invention is composed of
a first connector 30 and a second connector 31. The first
connector 30 includes a first housing 33 for housing first
optical connector elements (plugs) 32 (shown in Fig. 3a).
The second connector 31 includes a third housing 36 for
housing second optical connector elements (jacks) 35 (shown
in Fig. 3a) connected to the first optical connector
elements 32. This third housing 36 is slidable within the
second housing 34 in the axial direction of the optical
connector elements 32 and 35.
Before the first connector 30 is connected to the
second connector 31, the second housing 34 and the third
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CA 02354172 2001-08-08
housing 36 are engaged with each other by first engage
means composed of a first projection portion 37 having an
inclined surface 37a and an engage surface 37b formed in
the second housing 34 and a first elastic engage lever 38
having a claw portion 38a and a side projection 38b formed
in the third housing 36.
When the first connector 30 is connected to the second
connector 31, the first housing 33 and the third housing 36
are engaged with each other by second engage means composed
c~F ~, :second projection portion 39 Formed i.n the third
housing 36 and a second elastic engage lever 40 having a
claw portion 40a and a side projection 40b formed in the
first housing 33.
After the first connector 30 and the second connector
31 have been connected, since the first engage means 37 and
38 between the second housing 34 and the third housing 36
is released by a first engage release means composed of a
first release member 41 having an inclined surface 41a for
deforming the first elastic engage lever 38 in the
direction perpendicular to the axial direction of the
optical connector element, the third housing 36 is slidable
relative to the second housing 34 in the axial direction of
the optical connector element.
When the first connector 30 and the second connector
31 are disconnected, the second engage means 39 and 40
between the first housing 33 and the third housing 36 is
released by a second engage release means composed of a
second release member 42 having two inclined surfaces 42a
and 42b for deforming the second elastic engage lever 40 in
the direction perpendicular to the axial direction of the
optical connector element.
.....
The engagement conditions of the optical connector
according to the present invention will be explained
hereinbelow in further detail with reference to Figs. 3(a)
to 3(j), in which the engagement and disengagement steps of
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CA 02354172 2001-08-08
the optical connector according to the present invention
are shown in order.
Fig. 3(a) shows a status where two connectors 30 and
31 are not yet connected. The first connector 30 is fixed
to a back panel 5, and the second connector 31 is fixed to
a package board 1. Two first optical connector elements 32
are supported within the first housing 33 of the first
connector 30. The third housing 36 is disposed within the
second housing 34 slidably in the right and left direction
in Fig. 3(a). Before engagement of these two connectors 30
and 31, the third housing 36 is engaged with the second
housing 34 by the first engage means 37 and 38 so as not to
be slid toward the right direction, because a claw portion
38a of the first elastic engage lever 38 is engaged with a
first projection portion 37. Plural second optical
connector elements 35 are supported within this third
housing 36.
In engagement, the package board 1 is moved toward the
back panel 5 in the leftward direction in the drawing to
insert the second housing 34 into the first housing 33. In
this case, an end portion 44 of the second connector 31 is
guided along a guide surface 45 of an end portion 43 of the
first connector 30.
Fig. 3(b) shows a status where the second housing 34
and the third housing 36 are fitted to the first housing
33. In these conditions, end portions 32a of the first
optical connector elements 32 supported within the first
housing 33 and end portions 35a of the second optical
connector elements 35 supported within the third housing 36
are both opposingly located so as to be smoothly coupled to
each other.
Further, since the side projection portion 40b of the
second elastic engage lever 40 is deformed in the downward
direction in the drawing by the inclined surface 42c of the
second release portion 42 and brought into contact with a
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CA 02354172 2001-08-08
lower flat surface 42b of the second release portion 42,
the second housing 34 and the third housing 36 can be
smoothly inserted into the first housing 33 without
interference of the second elastic engage lever 40 with the
second and third housings 34 and 36, so that the second
engage lever 40 can be engaged with the second projection
39.
Fig. 3 (c) shows a state where the package board 1 is
further pushed toward the back panel 5. Under these
conditions, the first and second engage means 37, 38 and
39, 40 are both brought into engagement. That is, the
first projection portion 37 is kept engaged with the first
engage lever 38 in the first engage means, and further the
second elastic engage lever 40 is slid down from the second
release member 42 so that the claw 40a of the second
elastic engage lever 40 is located within a groove 46
formed in the third housing 36.
Therefore, a resiliency between the first optical
connector elements 32 and the second optical connector
elements 35 is indirectly applied to the back panel 5 and
the package board 1, respectively via the three housings
33, 34 and 36 and the first and second engage means 37, 38,
39, and 40.
Under these conditions, since the first optical
connector elements 32 and the second optical connector
elements are coupled to each other, an urging force of
about 1 kgf per fiber is generated between the first
optical connector element 32 and the second optical
connector element 35. However, this force is received by
the back panel 5 and the package board 1 via these housings
33, 34 and 36.
Fig. 3(d) shows a state where the package board 1 is
further pushed toward the back panel 5. When the package
board 1 is further pushed, the second housing 34 and the
third housing 36 are both pushed into the first housing 33.
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CA 02354172 2001-08-08
Therefore, the side projection portion 38b of the first
elastic engage lever 38 of the first engage means is pushed
downward by the inclined surface 41a of the first release
member 41, so that the first claw portion 38a is disengaged
from the first projection portion 37 of the first engage
means.
Fig. 3 (e) shows a state where the package board 1 is
further pushed a little from the state shown in Fig. 3(d),
to release the first engage means. Since the engagement
between the first projection portion 37 and the first claw
portion 38a is released, the third housing 36 is shifted in
the rightward direction by a resiliency generated between
the first optical connector elements 32 and the second
optical connector elements 35, until the second projection
portion 39 is brought into contact with the second elastic
engage lever 40 of the second engage means. In this state,
the first connector 30 is connected to the second connector
31.
Under these conditions, the resiliency between the
connector elements is received by the second projection
portion 39 and the second elastic engage lever 40 of the
second engage means via the first housing 33 and the third
housing 36, without applying the resiliency to the back
panel 5, the second housing 34 and the package board 1. In
other words, although the first housing 33 supporting the
first optical connector elements 32 and the third housing
36 supporting the second optical connector elements 35 are
strongly coupled to each other by the second engage means
39 and 40, these housings 33 and 36 are floated from the
second housing 34 and the package board 1 with respect to
the resiliency.
Fig. 3(f) shows a state where the package board 1 is
inserted until the end portion 44 of the second housing 34
is brought into contact with the bottom portion 47 of the
first housing 33. In this case, even if the package board
- 27 -
CA 02354172 2001-08-08
1 and the second housing 34 are moved in the leftward
direction by a distance C between the end portion 44 and
the bottom portion 47 as shown in Fig. 3(e), since the
third housing 36 and the first housing 33 are kept engaged
by the second projection portion 39 and the second engage
claw 40a of the second engage lever 40, the positional
relationship between the third and first housings 36 and 33
are kept unchanged. Therefore, it is possible to maintain
the same optical fiber connection conditions as shown in
Fig. 3(e).
Figs. 3(g) to 3(j) show the disengagement steps of the
optical connector according to the present invention in
order.
Fig. 3(g) shows a state where the package board I is
removed in the rightward direction from the engagement
state as shown in Figs. 3(e) and 3(f). When the package
board 1 is moved in the rightward direction, the second
housing 34 fixed to the package board 1 is also moved in
the same direction. However, since the third housing 36 is
engaged with the first housing 33 by the second projection
portion 39 and the second elastic engage lever 40 of the
second engage means, the third housing 36 is not moved.
Therefore, when the second housing 34 is moved in the
rightward direction relative to the position of Fig. 3(e),
the first projection portion 37 deformes the elastic first
engage lever 38 downward in the first engage means. In
more detail, the claw portion 38a of the first elastic
engage lever 38 slides on the inclined surface 37a of the
first projection 37 and comes on the flat surface 37b of
the first projection portion 37 of the first engage means.
Fig. 3(h) shows a state whether the package board 1 is
further moved rightward from the position shown in Fig.
3(g). The claw portion 38a of the first elastic engage
lever 38 passes over the first projection portion 37 in the
first engage means, so that the first engage means 37, 38
- 28 -
CA 02354172 2001-08-08
and the second engage means 39, 40 are both kept engaged in
the same way as shown in Fig. 3(c).
Fig. 3 ( i ) shows a state where the package board 1 is
further moved in the rightward direction. Since the second
housing 34 fixed to the package board 1 also moves in the
rightward direction, the second release portion 42 of the
second housing 34 moves in the same direction. Since the
inclined surface 42a of the second release portion 42 is
brought into contact with the side projection portion 40b
of the second elastic engage lever 40, the projection
portion 40b of the second elastic engage member 40 of the
second engage means is deformed downward, so that the
second elastic engage lever 40 and the second projection
portion 39, that is, the second engage means is released.
Since the engagement between the first housing 33 and the
third housing 36 is released due to the release of the
second release means, the third housing 36 is moved
rightward to a position where the first claw portion 38a is
engaged with the first projection portion 37 by the
resiliency generated between the first optical connector
elements 32 and the second optical connector elements 35.
Fig. 3(j) shows a state where the package board 1 is
further moved rightward from the position shown in Fig.
3(i). The side projection portion 40b of the second
elastic engage lever 40 of the second engage means slides
on the flat surface 42b of the second release portion 42,
and the second claw portion 40a is deformed to a position
where the claw portion 40a is not interfaced with the
second projection portion 39 of the second engage means.
Since the engagement between the third housing 36 and the
first housing 33 is released, the package board 1 can be
moved further rightward together with the second housing 34
to the disengagement position as shown in Fig. 3(a).
In the above-mentioned embodiment, the first engage
means 37, 38, the second engage means 39, 40, the first
- 29 -
CA 02354172 2001-08-08
engage release means 41 and the second engage release means
42 are all disposed one by one respectively on each side
surface of the optical connector. However, it is also
possible to provide a plurality of each of these means on
each side surface thereof. Further, each of these means
can be provided on all the (upper and lower and right and
left) sides of the optical connector.
Fig. 4 shows a second embodiment when seen from a
direction perpendicular to the package board 1, and Fig. 5
shows the same second embodiment when seen from a direction
parallel to the package board 1.
In this second embodiment, the optical connector is
composed of a first connector 50 and a second connector 51.
The first connector 50 is composed of a first housing 52
for supporting first optical connector elements 32. The
second connector 51 is composed of a second housing 53 and
a third housing 54 for supporting second optical connector
elements 35 coupled to the first optical connector elements
32. The second housing 53 is fixed to the package board 1
with screws 55. The third housing 54 is disposed within
the second housing 53 so as to be slidable in the axial
direction of the second optical connector elements 35.
Before the first connector 50 is connected to the
second connector 51, the second housing 53 and the third
housing 54 are engaged with' each other by first engage
means composed of a first projection portion 56 formed in
the second housing 53 and a first elastic engage lever 57
having a claw portion 57a formed in the third housing 54.
when the first connector 50 and the second connector
51 are connected to each other, the first housing 52 is
engaged with the third housing 54 by the second engage
means composed of a second projection portion 58 formed in
the third housing 54 and a second elastic engage lever 59
formed in the first housing 52.
- 30 -
CA 02354172 2001-08-08
After the first connector 50 has been connected to the
second connector 51, the first engage means 56 and 57
between the second housing 53 and the third housing 54 is
released by a first engage release mean 60, so that the
third housing 54 is slidable relative to the second housing
53 in the axial direction of the optical connector elements
35. The first engage release means is composed of a
release member 60 having a first inclined surface 60a for
deforming the first elastic engage lever 57 in the
direction perpendicular to the axial direction of the
optical connector elements 35.
When the first connector 50 is disengaged from the
second connector 51, the second engage means 58 and 59
between the first housing 52 and the third housing 54 is
released by a second engage release means composed of a
release portion 61 having a second inclined surface 61a for
deforming the second elastic engage lever 59 in the
direction perpendicular to the axial direction of the
optical connector elements 32.
The operation of the engagement and disengagement is
the same as in the first embodiment.
In the second embodiment, since a pair of engage means
and release means are provided on the upper and lower and
the right and left side surfaces of the optical connector
housings in symmetry with respect to the optical connector,
it is possible to stably, receive the resiliency of the
optical connector elements under well-balanced conditions.
Therefore, this second embodiment is preferable to an
optical connector for connecting a large number of optical
connector elements.
As described above, in the optical connector according
to the present invention, since the connector engagement
can be released by simply removing the package board, it is
possible to realize a plug-in optical connector excellent
in connection workability. Further, even if the number of
- 31 -
CA 02354172 2001-08-08
the optical connector elements and the number of the
package boards mounted on the unit frame increase, since no
excessive force will not be applied to the back panel and
the unit frame, it is possible to prevent the back panel
and the unit frame from being deformed or damaged.
Therefore, it is possible to increase the number of optical
connector elements to be mounted on the back panel or the
package board and therefore the assembly density of the
optical connector elements.
Further, after the optical connector elements have
been connected, since it is possible to push the package
board a little toward the back panel, it is possible to
absorb the dimensional error between the package board and
the unit frame, thus allowing the optical connectors
according to the present invention to be widely and
economically used for various optical systems.
The second feature of the present invention relates to
a plug-in connector supporting structure applicable to a
book-self mounting unit, in which a number of vertical
package boards are arranged in book-self manner and
connected to a back panel via connectors.
Prior to the description of the connector supporting
structure, a reference will be made to a prior-art
supporting structure.
A plug-in connector mounting structure is also
disclosed in U.S. Patent No. 4,895,425, for instance. The
plug-in connector is used to connect a package board on
which various parts are mounted to a back panel arranged on
the reverse surface of a unit frame in which a plurality of
package boards are mounted in book self manner.
The plug-in connector is composed of a back panel
connector attached to the back panel and a package
connector attached to the package board.
- 32 -
CA 02354172 2001-08-08
In these plug-in connectors, the connector housing
attached to the back panel is usually supported by the back
panel in floating structure in order to realize an aligning
engagement between the back panel connector and the package
S board connector by absorbing location error produced when the
connectors are attached to the package board and the back
panel or the unit frame.
FIG. 6 shows a prior-art floating structure disclosed
in the afore-mentioned document, in which a float pin 102 is
fixed to a back panel 101; a float hole 103a is formed in a
back panel housing 103; and the back panel housing 103 is
floatingly supported by the back panel 101 via a gap between
a float axle portion 102a of the float pin 102 and the float
hole 103a.
In this prior-art floating structure, since the floating
portion is provided within the housing 103, the connector
shape inevitably increases. Further, the package housing 104
is fixed to the package board 105 with fixing screws lOS. In
engagement, even if the back panel housing 103 is dislocated
relative to the package housing 104, since the guide pin 107
is loosely fitted to the guide hole 108, the floating back
panel housing 103 is shifted so as to be aligned with the
package housing 104.
In case the looseness is excessively large, the back
panel housing 103 is declined, and therefore the guide pin
107 is not well fitted to the guide hole 108. In case the
looseness is excessively small, the two housings cannot be
well aligned. Therefore, the float hole and the float axle
portion must be formed precisely for providing an accurate
floating engagement.
FIG. 7 shows another prior-art floating structure
disclosed in the afore-mentioned document, in which the float
axle portion 102a of the float pin 102 is disposed outside
the back panel housing 103; another member 109 formed with
3S a float hole 109a is fixed to the back panel 101; and
- 33 -
F~i~~P~D JUL 2 0 2001
CA 02354172 2001-08-08
the float axle portion 102a is passed through the float
hole 109a. Since the diameter of the hole 110 farmed in
the back panel 101 is determined simply larger than that of
the float hole 109a, in practice the float function is
mainly dependent upon the shapes of the float hole 109a and
the float axle portion 102a.
In this prior-art structure, since the additional
member 109 formed with the float 109a and means for fixing
the member 109 are required, an additional space is
necessary in the thickness direction of the back panel.
Further, in this example, the member 109 formed with the
float hole 109a is indirectionally supported by the back
panel 101 frictionally via electric terminals 110 fixed to
the back panel 101.
When the prior-art floating structure is adopted to
floatingly support the package housing 104, since the space
required for the floating structure is large, there exists
a problem in that the connector shape is large and
therefore the connector mounting density and the package
mounting density decrease.
Further, although it is possible to consider such a
structure that the float holes are directly formed in the
package board 106, since high manufacturing precision is
required to form correctly-circular float holes, there
exists a problem in that the cost required to bore the
float holes in the package board 104 at high precision
inevitably increases.
The second feature of the optical connector according
to the present invention is to realize a simple and
precious floating structure for floatingly supporting the
package housing on the package board. An embodiment of the
present invention will be described in detail hereinbelow
with reference to the attached drawings.
Figs. 8 to 11 show an embodiment of the present
invention. Figs. 8(a) and 8(b) are partially
- 34 -
CA 02354172 2001-08-08
cross-sectional, plan and side views. Figs. 9(a) and 9(b)
are cross-sectional views taken along the lines II-II and
III-III in Fig. 8(a), respectively. Fig. 10(a) is a plan
view showing a slot member. Fig. 10(b) is an enlarged view
showing the axle member. Fig. 11 is an exploded view
showing the essential portions for assistance in explaining
the method for assembly.
As shown in Fig. 8(a), a back panel housing 120 for
supporting optical elements 121 is fixed to a back panel
122. A package housing 123 for supporting optical elements
124 is movably mounted on the back panel housing 120. The
package housing 123 is provided with two floating
structures as shown by dashed lines so as to be slidable up
and down in the drawing relative to the package board 125.
As shown in Fig. 8(b), the package housing 123
supported by the package board 125 via the floating
structure composed of~~.an axle member 127 extending from a
support surface 126 of the housing 123 and a slot member
130 and a nut member 128 fixed to an end of the axle member
127. The floating support condition will be explained in
further detail hereinbelow with reference to Figs. 9(a) and
9(b).
As shown in Fig. 9(a), a through hole 129 is formed in
the package board 125, and the slot member 130 is fitted to
the through hole 129. The axle member 127 extending.from
the support surface 126 of the package housing 123 is
passed through the slot member 130. The nut member 128 is
fixed to an end of the axle member 127. The diameter 131
of the nut member 128 is larger than that of the through
hole 129. Therefore, the package housing 123 is supported
by the package board 125 between the support surface 126 of
the package housing 123 and the support surface 132 of the
nut member 128. Since a gap between a float slot 133 of
the slot member 130 and the parallel straight portions 134
of the axle member 127 is small in the direction that the
- 35 -
CA 02354172 2001-08-08
package 125 is inserted (i.e. the right and left direction
in Fig. 8(a)), the package housing 123 will not. move
relative to the package board 25.
On the other hand, as shown in Fig. 9(b), since the
width of the float slot 133 of the slot member 130 is
larger than that of the outer surface portion 135 of the
axle member 127 and therefore the gap between the two is
large in the direction perpendicular to the direction that
the package board 125 is inserted (i.e. the upper and lower
direction in Fig. 8(a)), the axle member 127 is movable
within the float slot 133. Further, although the axial
portion of the nut member 128 is brought into contact with
the shoulder surface 136 of the outer surface portion 135
of the axle member 127, a gap between the support surface
126 and the shoulder surface 132 is determined a little
larger than the thickness of the package board 125.
Therefore, the package housing 123 is loosely movable in
the direction perpendicular to the package board insertion
direction.
As shown in Fig. 10(a), the slot member 130 is
pressure fitted to the through hole 129 formed in the
package board 125. The axle member 127 is loosely fitted
to the float slot 133 and movable in the major axis of the
slot 133. In more detail, the axle member 127 is formed
with a pair of parallel portions 138 having a width a
little narrower than that of the minor axis of the float
slot 133 and extending in the vertical direction in the
drawing to allow the axle member 127 to be slidable along
the major axis of the slot 133 only in the vertical
direction. Since the axle member 127 is movable along the
slot 133, the package housing 123 is floatingly movable
along the major axis of the slot 133 without moving along
the minor axis of the slot 133. Further, since the slot
member 130 can be formed by molding process, it is possible
to precisely manufacture the float slot 133 at a relatively
low cost.
- 36 -
CA 02354172 2001-08-08
As shown in Fig. 10(b), the axle member 127 is formed
with a float axle portion 135 and a threaded axle portion
139. The float axle portion 135 is formed with a pair of
parallel portions 140 into an oval shape in cross section.
The float axle portion 135 is fitted into the float slot
133 formed in the slot member 130 by mating the parallel
portions 140 of the float axle portions 135 with the
parallel portion 138 of the float slot 133.
Since the float hole is formed into a float slot, the
float axle portion 135 is movable only along the major axis
direction of the float slot 133 without rotation within the
float slot 133 of the slot member 130. In other words, the
slot member 130 will not rotate relative to the package
board 125. Therefore, when two or more floating structures
are provided as shown in Fig. 8(a), even if the slot member
130 is loose relative to the package board 125, it is
possible to determine the movable direction of the package
housing 123 relative to the package board 125.
In general, since the housing i23 is manufactured by
molding, it is possible to manufacture the axle member 127
at high precision and at low cost.
Fig. 11 shows a method of assembling the floating
structure when the package housing 123 is attached to the
package board 125. The slot member 130 is fitted to the
through hole 129 formed in the package board 125; the axle
member 127 of the package housing 123 is inserted into the
float slot 133 of the slot member 130, and the nut member
128 is screwed to the end threaded portion 7.39 of the axle
member 127.
In this embodiment, the floating (movable) direction
of the package housing 123 is determined in the direction
pe.rpendicul.ac to the optical ax.i.s of the optical connector
element 124. However, when the housing 123 is required to
be moved in another direction, only the major axis
direction of the axle member 127 is changed without
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CA 02354172 2001-08-08
modifying the shapes of the through hole 129, the slot
member 130, and the nut member 128. Further, the floating
distance (movable stroke) can be controlled by changing the
dimensions of the parallel portion 138 of the float slot
133 or the parallel portion 140 of the axle member 127.
As described above, according to the present
invention, it is possible to floatingly mount the package
connector housing to the package board at high precision by
simple floating structure.
Further, since only simple through holes are required
to be formed in the package board, it is possible to mold
the package board at high precision and at low cost.
Further, when molding process is adopted, it is possible to
control the floating distance (movable stroke) at higher
precision at lower cost even when the floating structure is
more complicated.
Further, when the package boards are mounted in
book-self fashion, although the height of parts mounted on
the package board is limited so that the two adjacent
package boards will not interfere with each other, since
floating parts are arranged on the connector mounting side,
it is possible to realize the floating structure without
increasing the size (thickness? of the package housing.
Further, since no floating parts are provided for the
connector housing, it is possible to increase the connector
element mounting area of the connector housing; that is,
the number of mountable optical connector elements can be
increased. Further, since only the fixing nut is provided
on the reverse surface of the package board, it is possible
to increase the mounting density of the package boards to
the unit frame, without interference between the two
adjacent package boards.
Further, since the package housing is Gloated, it is
unnecessary to float the back panel connector, being
diLGerent Groin the prior-art plug-in connccl.or. ~rrieretorc,
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CA 02354172 2001-08-08
it is possible to fix the back panel housing to the back
panel. Therefore, in case the back panel connector element
cable connected to an external device is pulled, since no
force is applied to the package board within the unit, it
is possible to increase the reliability of the device.
The third feature of the present invention relates to
an optical connector ferrule holding structure for
connecting an optical fiber of an optical connector plug,
and preferably applied to a plug-in optical connector used
to mount a package board on which various optical and
electrical parts are mounted is assembled as a unit.
Prior to description of the ferrule holding structure,
a reference will be made to a prior-art holding structure.
(1) JIS C5970 prescribes an FO1 single core optical
fiber connector as an example of a prior-art optical
connector for connecting optical fibers. In this
connector, an optical fiber is fixed at the center of a
cylindrical ferrule; the ferrule is inserted into a
cylindrical hollow alignment sleeve formed with a precisely
formed inner hollow portion so that end surfaces of two
ferrules butt against each other. This optical connector
is composed of a plug and an adaptor, and a pair of plugs
are engaged with each other from both the sides of the
adaptor.
Fig. 12 shows a one-side plug 211 and an adaptor 212.
An optical fiber 224 is bonded to a ferrule 221, and the
ferrule 221 is floatingly supported inside a plug housing
222. To push end surfaces of the ferrules 221 against each
other, the ferrule 221 is urged by a spring 223 within the
plug housing 222. 'This spring 223 is housed within l:he
plug housing 222 so as to be compressed to a predetermined
urging force, the urging force is received when a flange
portion 221b of the ferrule 221 is brought into contact
with an inner wall 222a formed in the plug housing 222.
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A sleeve holder 226 is supported in the adaptor 212,
and an elastic sleeve 225 for supporting two ferrules 221
is disposed within the sleeve holder 226 as shown in Fig.
12. When two ferrules 221 are supported via the elastic
sleeve 225 within the adaptor 212, two optical fibers 224
are connected with the adaptor 212 interposed between the
two plugs 211.
(2) On the other hand, U.S. Patent No. 4,895,425
discloses a plug-in connector used to transmit optical
signals between a package board (on which various optical
modules are mounted and which is mounted to a unit frame)
and another package board or an external device. In the
case of the above plug-in optical connector, since a
plurality of connectors are mounted on a package board,
there inevitably exists an error with respect to the
connector mounting location or the unit frame and package
board manufacturing process, so that it is required to
maintain correct mutual positional relationship among
plural connectors by absorbing an engagement error of about
1 mm in the axial direction of the optical connector
element (ferrule). Therefore, plug-jack type optical
elements different from the optical fiber connector shown
in clause (1) above is used.
(3) To increase the number oL fibers per package
board in the plug-in connector as described above, it is
necessary to prevent the ferrule urging force from being
directly applied to the back panel, as already explained
with reference to Figs. 2 and 3. In this optical
connector, when the package board is inserted into the
optical connector, two opposing optical connectors are
automatically locked independently, and when the package
board is removed from the optical connector, the two
opposing optical connectors are automatically unlocked to
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CA 02354172 2001-08-08
allow the package board to be removable from the back
panel. In this case, since the positional relationship
between two optical elements is maintained correctly under
locked condition, it is possible to apply the single fiber
connector structure (plug-adapter-plug structure) as
explained in clause (1) above or to use the single core
optical connector and the plug in common. Therefore, in
this optical connector, a plug and a jack having a sleeve
holder with a slitted sleeve are usable.
Figs. 13(a) to 13(c) show a prior-art plug structure
and the positional relationship between the plug and jack
when the single optical fiber connector is applied to the
plug-in optical connector.
With reference-to these drawings, the ferrule 221 for
supporting the optical fiber 224 is urged via the flange
portion 221b by a spring 223, and the flange portion 221b
is in contact with an inner wall 222a of a plug housing
222.
The ferrule 221 and another ferrule 221A supported by
a jack side ferrule (not shown) are butted against each
other within the elastic sleeve 225 by inserting a sleeve
holder 226 (fitted into the jack side plug) into the plug
211 to couple the two optical fibers. In the case of the
plug-in optical connector, an axial engagement error of
about 1 mm can be absorbed by a clearance between the inner
wall 222a and the sleeve holder 226 when the two ferrules
are coupled. After coupled, the two optical connectors are
automatically locked independently when the package board
is inserted to maintain the two element positional
relationship correctly.
Fig. 14(a) and 14(b) show the ferrule 221. The
ferrule 221 is formed with a flange portion 221b with two
key grooves 221c. Therefore, when keys (not shown)
provided for the plug housing 222 are engaged with the key
grooves 221c, it is possible to prevent the ferrule 21 from
being rotated.
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CA 02354172 2001-08-08
In the optical connector explained in clause (3)
above, since the connector 213 is of plug-in type as in
clause (2) above, it is necessary to absorb an axial
engagement error of about 1 mm when coupled. Therefore, it
is necessary to consider the first extreme coupling
position where the plug and jack are close to each other as
shown in Fig. 13(b) and the second extreme coupling
position where the plug and jack are apart from each other
by a clearance between the inner wall 222a and the sleeve
holder 226 as shown in Fig. 13(c). To provide this
clearance, the elastic sleeve 225 must be shortened or the
ferrule 221 must be lengthened. If the elastic sleeve 225
is short, the connection reliability is deteriorated; and
if the ferrule 221 is long, the bending strength of the
ferrule 221 is reduced and not preferable from the
standpoint of interchangeability with other optical
connectors. Further, although it may be possible to
provide another axial engagement error absorbing mechanism
separately from each plug element, this results in another
problem in that the size of the plug housing 222 is
increased and thus the fiber mounting density is reduced.
The third feature of the optical connector according
to the present invention is to provide an optical connector
Lerrule support. structure and optical connector plug whose
optical connector element can be engaged and disengaged by
simple insertion anc~ removal operation and by which an
axial engagement positional error of about 1 mm can be
absorbed when used as a plug-in optical connector.
Further, another object of the present invention is to
provide an optical connector ferrule support structure
applicable to the self-lock optical structure as disclosed
with reference to Figs. 2 and 3.
With reference to Figs. 15 to 17, a ferrule support
structure and an optical connector plug used for the
ferrule support structure according to the present
invention will be explained hereinbelow.
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CA 02354172 2001-08-08
Fig. 15(a) is a cross-sectional view showing an
embodiment of the optical connector plug according to the
present invention; Fig. 15(b) is a cross-sectional view
taken along the line A-A in Fig. 15(a); Fig. 15(c) is a
cross-sectional view taken along the line B-B; Fig. 17(a)
is a front view showing the ferrule; and Fig. 17(b) is a
side view showing the ferrule.
As shown in Fig. 15(a), an optical fiber 204 is bonded
to a body of a ferrule 201, and the ferrule 201 is
floatingly supported within the plug housing 202. The
ferrule 201 is formed with a flange portion 201b slidably
fitted into the plug housing 202. As shown in Figs. 15(b)
and 17(a) the flange portion 201b is formed into a square
shape whose corners are chamfered in cross section.
Therefore, the plug housing 202 is formed with a square
hollow portion to which the flange portion 201b of the
ferrule 201 is fitted without rotation. The shape of the
flange portion 201.b is not limited to a chamfered square
shape, and a polygonal (e.g. hexagonal) shape can be
applicable. A spring 203 is housed within the plug housing
202 to urge the flange portion 201b of the ferrule 201 in
l:he rightward direction in fi.g. l.5(a).
The large-diameter hollow portion 254 of the plug
housing 202 communicates with the small-diameter ferrule
support portion 252 via a shoulder opening portion 253 to
receive the outer circumferential edge of the flange
portion 201b by a shoulder portion 253. As shown in Fig.
15(c), an end portion 201a of the ferrule 201 is floatingly
supported within a ferrule support portion 252 and fitted
to a sleeve holder 206, as described later.
The ferrule support structure will be explained with
reference to Figs. 16(a) and (b), in which a plug and jack
are engaged. The plug includes an elastic slit sleeve 205
and a sleeve holder 206 for supporting the slit sleeve 205.
In Fig. 16, no jack side is shown. The sleeve holder 206
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CA 02354172 2001-08-08
is slidably fitted into the ferrule support portion 252,
and inserted into the plug housing 202 through the shoulder
opening portion 253.
In the ferrule support structure as described above,
the sleeve holder 206 can be inserted into the plug housing
202, because no inner wall 222a formed in the prior-art
structure as shown in Fig. 13 is formed. Therefore, as
shown in Fig. 16(a), it is possible to insert the sleeve
holder 206 deep from the initial ferrule position beyond
the shoulder portion 253 against the urging force of the
spring 203, thus absorbing an axial engagement error when
used as a plug-in optical connector. Accordingly, as shown
in Fig. 16(b), the deepest engagement position can be
determined in the state where the ferrule 201 is the most
deeply inserted into the slit sleeve 205 in the same way as
in the ordinary single fiber optical connector.
Further, it is necessary to couple two ferrules in the
same angular position, in order to obtain an excellent
optical connector coupling and decoupling characteristics.
In the ferrule support structure of the present invention,
since the ferrule flange portion 201b is formed into
chamfered square shape, it is possible to reliably
determine the angular position of the ferrule 201 about the
axis thereof, thus permitting an excellent ferrule
engagement and disengagement characteristics.
As described above, in the optical connector ferrule
support structure and the optical connector plug according
to the present invention; since it is possible to insert
the ferrule from the initial position further deep by
inserting the sleeve holder 206 into the plug housing 202,
the axial engagement error can be easily absorbed, without
providing another special parts or mechanism. Further, the
structure can be effectively applied to the small-sized and
multifiber plug-in optical connector. In addition, since
the structure can be applied to the single fiber optical
- 44 -
CA 02354172 2001-08-08
connector, it is possible to reduce the cost of the optical
connector plug, because.the plug can be used in common for
both the single and multifiber plug-in optical connector.
Further, the angular position of the ferrule can be
determined by the square flang portion of the ferrule, it
is possible to further reduce the size of the optical
connector, which is effective in particular when a
multifiber plug-in optical connector is constructed.
The fourth feature of the present invention relates to
an optical connector for removably connecting an optical
cord, and in particular to secure a coupling force against
a tensile force applied to the optical cord in connection.
Prior to the description of the optical connector, a
reference will be made to a prior-art optical connector
with reference to the attached drawings.
When a plurality of optical cords including optical
fibers, respectively are removably coupled, in general an
optical connector is used in such a way that an optical
plug is connected to an end of an optical cord,
respectively, and the optical cords are connected to each
other with these optical plugs via a plug adapter. A high
performance small coupling loss optical connector easily
and removably engageable with a plug adapter is disclosed
in Japanese Published Unexamined Patent Appli. No.
63-239407, for instance as a single core optical connector.
Fig. 1(b) shows the structure of this single core
optical connector. An optical plug 12 is connected to an
end portion of an optical cord (fiber) 18. An plug adapter
10 removably engaged with the optical plug 12 includes an
adapter housing 10a. Elastic levers 17 are provided within
the adapter housing 10a. Each elastic lever 17 is formed
with an engage claw 20 and two side projections 17a of the
free end thereof. On the other hand, the optical plug 12
includes a ferrule 15, a plug housing 16 formed with an
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CA 02354172 2001-08-08
engage projections 18, and a knob block 9 slidably attached
to the plug housing 16 and formed with release projections
11.
Therefore, when the optical plug 12 is engaged with
the plug adapter 10, since the engage claws 20 formed in
the elastic levers 17 provided in the plug adapter 10,
respectively are brought into contact with the engage
projections 18 formed in the plug housing 16 of the optical
plug 12, the plug adapter 10 is coupled to the optical plug
12. Reversely, when the optical plug 12 is removed from
the plug adapter 10, since the knob block 9 of the optical
plug 12 is removed from the adapter housing 10, the release
projections 11 formed in the knob block 9 are brought into
contact with the side projections 17a to deform the elastic
arm 17, so that the engagement between the claws 20 and the
engage projections 18 is released to allow the optical plug
12 to be decoupled from the plug adapter 10.
Fig. 18 shows an enlarged view showing the prior-art
engagement. portion oL the ningle core optical connector, in
which the engagement between the optical plug 302 and the
plug adapter 303 is achieved between the claw 306 of the
elastic lever 304 provided in the adapter housing 305 and
the engage projection 309 formed at an end of the plug
housing 310. Therefore, when the optical plug 302 is
pulled in the rightward direction in the drawing, a force
is transmitted to the claw 306 via the engage projection
309. In this case, since a point of force application is
offset by a distance d from the base portion of the elastic
lever 304, a counterclockwise moment M is applied to the
elastic lever 304 at the fixed portion of the elastic lever
304.
Therefore, when a tensile force between the optical
plug 302 and the plug adapter 303 is large, there exist
problems in that the free end portion of the elastic lever
304 is bent upwardly, so that the engage surface of the
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CA 02354172 2001-08-08
claw 306 slips away from the engage surface of the engage
projection 309 into disengagement condition and therefore
the optical plug 302 is removed from the plug adapter 303.
To overcome this problem, the frictional coefficient
between the engage surface of the claw 306 and that of the
engage projection 309 has been increased or an angle
subtended by the tensile direction of the optical plug 302
and the engage surface between the claw 306 and the engage
projection 309 has been determined to be an acute angle, as
disclosed in the afore-mentioned document 63-239407.
However, when the optical connector is small in size,
since the dimensions of the claw 306 and the engage
projection 309 are also small, it is rather difficult to
obtain a sufficient frictional force between the claw 306
and the engage projection 309. Further, if the angle
between the tensile direction and the engage surface
(between the claw 306 and the projection 309) is determined
to be 'an acute angle, since a stress is concentrated to
these claw 306 and the fixed portion oL the engage
projection 309 and therefore these parts are easily broken,
it hes been c7iLCicult to prevent lhc optical plug 307 Crom
being removed from the plug adapter 303.
The fourth feature of the optical counter according to
the present invention is to provide an optical connector by
which the optical plug can be engaged with the plug adapter
firmly even when a large tensile force is applied to the
op~lcal cord.
1~'ig. 19 shows an embodiment oC a push-pull type
optical. connector according to the present i.nventi.on. Fig.
20 is a front view of the optical plug and Fig. 21 is a
plan view thereof. Fig. 22 shows a left side surface of
the optical connector shown in Fig. 19. .
A plug adapter 311 is used to connect two optical
plugs 314 under butt conditions. A cylindrical sleeve 312
is Lifted to the center of the plug adapter 31.1. A Lcrrule
- 47 -
CA 02354172 2001-08-08
313 is also closely fitted to the cylindrical sleeve 312.
An optical plug 314 having the ferrule 313 at one end is
formed with a plug housing 315. A square knob block 316 is
fitted to the plug housing 315 so as to be slidable within
a predetermined range in the axial direction of the optical
plug 314. The plug housing 315 to which an optical cord
317 is attached is formed with a pair of engage projections
318 at the inner end thereof. On both sides of these
engage projections 318, an engage release projection 321
having an insertion inclined surface 319 and a removal
inclined surface 320 is formed for the knob block 316 at
the end thereof.
The plug adapter 311 includes a coupling flange 322
and a square claw holder 323 into which the optical plug
314 is inserted. The square claw holder 323 is formed with
a pair of elastic arms 324 extending axially and inwardly
from outside to inside so as to sandwich the optical plug
314. Each elastic arm 324 is formed with a claw 325
engageable with each engage projection 318 oL the optical
plug 314. An engage surface 326 of this claw 325 is formed
facing inward, and an engage surface 327 of the engage
projection 318 is formed facing outward. Further, the
elastic arm 324 of the optical adapter 311 is formed with
two release side portions 328 (shown in Fig. 22) on both
the sides of the engage claw 325, respectively so as to be
brought into contact with the insertion inclined surface
319 and the removal inclined surface 320 of the engage
release projection 321 of the optical plug 314.
Therefore, as shown in Fig. 23, when the optical cord
317 is pul.l.ed and therefore the plug 314 is pulled in the
rightwt~rd d~ .recti.on Crom the optical. adapter 31 1 , al though
the tensile force is applied to the claw 325 via the engage
projection 318, since a point of force application is
offset inward by a distance d from the Lixed portion oL the
elastic arm 324 extending from the claw laolder 323, a
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CA 02354172 2001-08-08
counterclock wise moment M is generated around the fixed
portion of the elastic arm 324.
As a result, when a tensile force is applied so that
the optical plug 314 is removed from the plug adapter 311,
the free end of the elastic arm 324 is bent inward in the
direction that the engage surface 326 of the claw 325 is
brought into tight contact with the engage surface 327 of
the engage projection 318 to maintain the tight engagement
condition between the optical plug 314 and the plug adapter
311.
ns desori.bed above, when a tensile force is applied to
the optical cord 317, since the claw 325 is further tightly
engaged w.i.th the engage projection 37.8, i.t is poss.i.ble to
sufficiently increase the coupling strength between the
two, without increasing the frictional coefficient between
the engage surface 326 of the claw 325 and the engage
surface 327 of the engage projection 318 or determining the
angle between the optical cord removal direction and the
two engage surfaces 326 and 327 at an acute angle.
In particular, when the optical connector is small in
size, although the dimensions of the engage claw 325 and
the engage projection 318 are also small, it is unnecessary
to increase the frictional coefficienC of l.he two engage
surfaces 326 and 327 or to set the angle between the
optical cord removal direction and the two engage surfaces
326 and 327 to an acute angle. Therefore, it is possible
to reduce the stress concentration of the claw 325 and the
fixed portion of the engage projection 318, thus increasing
the strength of the claw 325 and the engage projection 318.
When the optical plug 314 is coupled to the plug
adapter 311, the knob block 316 is pinched by the fingers
and the end surface of the optical plug 314 is inserted
into the plug adapter 311. In this case, since the
insertion inclined surface 319 of the engage release
projection 321 formed at the end of the knob block 316 is
- 49 -
CA 02354172 2001-08-08
brought into contact with the engage release side
projection 328 (Fig. 22) of the elastic lever 324, the tree
end of the elastic arm 324 is bent away from the engage
projection 318. Subsequently, the removal inclined surface
320 is brought into contact with the engage release side
projection 328 of the elastic lever 324, so that the knob
block 316 is located within the plug adapter 311.
In parallel with the above operation, since the engage
projection 318 of the optical plug 314 is brought into
contact with an insertion inclined surface 329 of the claw
325 (opposite side to the engage surLace 3~G), l,hc tree end
of the elastic arm 324 is bent away Lrom the engage
pro jection 31F3. nLLer the cngnge prc~)r~c~ i r,n 3 1 f3 htna pinned
through the claw 325 of the elastic arm 324, the elastic
arm 324 is automatically is returned to the original
condition to engage the engage projection 318 with the claw
325 of the elastic arm 324.
On the other hand, when the optical plug 314 is
removed from the plug adapter 311, the knob block 316 is
pulled away from the plug adapter 311 in the rightward
direction. Therefore, the knob block 316 is moved away
from the optical plug 314 together with the optical plug
314 in the rightward direction. In this case, the removal
inclined surface 320 of the engage release projection 321
formed at an end of the knob block 316 is brought into
contact with the engage release side projection 32~ oL the
elastic arm 324, so that the end oI the clr~stic r~rm 3?.~1 i3
bent away from the engage projection 318. Therefore, the
engagement between the engage projection 318 and the claw
325 is released. Under these conditions, the optical plug
314 can be removed from the plug adapter 311 together with
the knob block 316.
Further, in this embodiment, in order to prevent the
so-called reverse insertion of the optical plug into the
plug adapter, the outer shape of the optical plug 314 is
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CA 02354172 2001-08-08
formed in asymmetry with respect to the axial center of the
ferrule 313. In more detail, as shown in Fig. 22 the plug
adapter 311 is farmed with a locating groove 330 on one
inner side wall thereof and the knob block 316 is formed
with a locating projection 331 on one outer side well
thereof so as to be engaged with the locating groove 330 as
shown in Fig. 20. Further, the widths of the engage
release projections 321 formed in the knob block 316 on
both the sides thereof as shown in Fig. 21 and the widths
of the engage release cutout portions 3 formed in the plug
adapter 311 as shown in Fig. 22 are determined to be
different between the right and left sides, respectively.
In other words, since the coupling orientation between the
plug adapter 311 and the optical plug 314 is determined,
when the optical plug 314 is inserted into the plug adapter
311 in the opposite erroneous direction, since the wider
engage release projection 321 interferes with the plug
adapter 311, it is possible to prevent the optical plug 314
from being inserted into the plug adapter in erroneous
orientation.
In the optical connector according to the present
invention, since a distance between thr cn~3 ,~.arfa~:e of the
ferrule 313 of the optical plug 314 and the engage surface
327 of the engage projection 318 can be reduced smaller
than that of the prior-art plug adapter shown in Figs. 1(b)
and 18, it is possible to determine the engage position
between the engage projection 318 of the optical plug 314
and the claw 325 of the elastic arm 324 at a position near
the inner end of the optical plug 314. Therefore, the
optical connector of the present invention is preferably
applicable to the plug-in optical connector.
Fig. 24 shows another embodiment of the optical
connector of the present invention, which is applied to a
plug-in optical connector fixed to a back panel side of a
book-self connector package unit.
- 51 -
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In the drawing, a main back panel housing 352
(substantially the same in structure as the plug adapter
311 already explained) and a subsidiary back panel housing
353 are attached to a pack panel 351 so as to sandwich the
pack panel 351 between the two housings 352 and 353. Into
this main back panel housing 352, an optical plug 354
(substantially the same in structure as the optical plug
314 already explained) is removably inserted.
The subsidiary back panel housing 353 and the back
panel 351 are formed with through holes 355 and 356,
respectively through which the optical plug 354 is passed.
An elastic arm 357 extends axially and inwardly from the
back panel side of the main back panel housing 352. When a
claw 358 of the elastic lever 357 is engaged with an engage
projection 360 of a plug housing 359, the optical plug 354
is coupled to the main back panel housing 352.
In this embodiment, when an optical cord 361 extending
from the optical plug 354 is pulled, since the tensile
force is applied to the claw 358 of the elastic arm 357 via
the engage projection 360 of the plug housing 359, the claw
358 and the engage projection 360 are more tightly engaged
with each other as in the embodiment shown in Figs. 19 to
22, so that the optical plug 354 is kept coupled with the
main back panel housing 352.
Further, the well-known structure can be adopted on
the package side. Or elese, the structure shown in Fig. 19
can be modified as shown in Fig. 24. Further, when the
optical plug 354 is removed from the main back panel
housing 352, the knob block 362 is moved in the leftward
direction in Fig. 24 in the same way as in the embodiment
shown in Figs. 19 to 22.
As described above, although the optical connector
according to the present invention has been applied to the
single core optical connector and the plug-in optical
connector, it is of course possible to apply the optical
- 52 -
CA 02354172 2001-08-08
connector according to the present invention to other
optical connectors. ,
In the optical connector according to the present
invention, even if a large tensile force is applied to the
optical cord, since the free ends of the elastic arms of
the plug adapter are deformed toward the engage projections
of the optical plug, it is possible to maintain the tight
engagement condition between the engage surfaces of the
claws of the elastic arms and the engage surfaces of the
engage projections of the optical plug. Further, the
optical plug is removed from the plug adapter by simply
moving the knob block away from the plug adapter, thus
realizing an optical connector of higher tensile strength
and excellent coupling/decoupling operability.
The fifth feature of the present invention relates to
an optical connector structure for connecting an optical
fiber, and more specifically to an optical connector
locating structure suitable for a plug-in optical connector
used to connect a package board on which optical or
electrical parts are mounted to a unit frame or suitable
when optical connectors are required to be arranged at high
mounting density.
Prior to the description of the optical connector, a
reference will be made to a prior-art optical connector
with reference to the attached drawings.
JIS prescribes F04 single-core optical fiber
connectors used to connect optical fibers, in which an
optical fiber is fixed to the center of a cylindrical
ferrule and this ferrule is inserted into a precise
cylindrical hollow alignment sleeve so that two opposing
ferrule end surfaces can be connected to each other.
Fig. 25 shows this optical connector composed of an
optical connector plug 401 and a connector housing 402
called adapter. A pair of optical connector plugs 401 are
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CA 02354172 2001-08-08
fitted to both the side surfaces of the connector housing
102 for coupling the two optical connector plugs 401.
The connector plug 401 is composed of a plug housing
404 for supporting a ferrule 403 attached to one end of the
optical fiber 400 and a knob 405. The plug housing 104 is
slidable in the axial direction of the ferrule 103 within
the knob 405. The connector housing 402 engaged with the
optical connector plug 401 is composed of a cylindrical
hollow alignment sleeve 406 to which the ferrule 403 is
inserted and an insertion hole 407 to which the end portion
of the knob 405 is inserted. These optical connector plug
401 and the connector housing 402 are coupled to each other
by fitting the ferrule 403 into the alignment sleeve 406
and fitting the knob 405 into the insertion hole 407,
respectively. Further, the above engagement is locked when
two claw portions 411 of two engage arms 410 of the
connector housing 402 are engaged with two engage recessed
portions 409 of two grooves 408 formed on two opposing side
surfaces of the optical connector 401, respectively.
When the optical connector as described above is used to
connect a single core optical fiber, generally two mating
plugs are coupled to each other in a predetermined
orientation so as to eliminate an eccentricity between the
ferrule and the optical fiber core, that is, to maintain a
required connection characteristics.
In the case of the F04 single core optical fiber
connector, therefore, a projection 412 is formed on one
side surface of the optical connector plug 401, and a
groove 413 fittable to this projection 4I2 is formed in the
connector housing 402 so that the optical connector plug
401 having two symmetrical surfaces can be engaged with the
connector housing 402 in a predetermined positional
relationship.
On the other hand, where package boards on each of
which various optical modules are mounted are attached to a
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unit frame and optical signals are transmitted between
these package boards and between the package board and an
external device, a plug-in optical is used as disclosed in
U.S. Patent No. 4,895,425 entitled "Plug-in Optical Fiber
Connector".
In the case of the plug-in optical connector, a
plurality of optical connector plugs are fitted to the
respective housings, and two mated .optical connector plugs
are connected simultaneously when the two housings are
coupled with each other. In this usage, it is required to
mount a plurality of optical connector plugs on a housing
at high mounting density.
Further, when a higher mounting density is required
for the ordinary single core optical connector, a method of
using an adapter is known to simultaneously couple a
plularity of plugs.
Figs. 26(a) and (b) show a connector housing 420 to
which a plurality of optical connector plugs 401 are
fitted. In this case, since each groove 421 for receiving
a projection 412 formed on the side surface of the optical
connector plug 401 is formed at each insertion hole 422 of
the connector housing 420, each partition wall 423 for
partitioning two adjacent insertion holes 422 is cut away
to minimize the mounting pitch, so that two adjacent
insertion holes 422 are connected to each other as shown.
When the optical connector plug 401 is coupled with the
connector housing 420, the optical connector plug 401 is
locked by engaging an engage ,member 424 formed on an inner
surface of each insertion hole 422 of the connector housing
420 with a groove 409 formed in a side surface of the
optical connector plug 401, in the same way as shown in
Fig. 25.
Fig. 26(a) shows a state where an optical connector
plug 401 is engaged with the above-mentioned connector
housing 420, in which the optical connector plug 401 is
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fitted to the connector housing 420 by engaging two grooves
409 and a single projection 412 formed in the side surfaces
of the optical connector plug 401 with two engage members
424 and a single groove 425 formed in the inner surfaces of
the connector housing 420.
GVhen the plug locating structure of the F04 optical
connector as described above is adopted, the following
problems arise:
Since the optical connector plug 401 is symmetrical
with respect to the center line passing through the middle
position of the groove 409, if the projection 412 is
assumed to be removed, it is possible to fit the optical
connector plug 410 into the insertion,hole 422 (No. 3), for
instance in two different directions as shown in Figs.
26(a) and (b). In case the optical connector plug 401 is
inserted in the direction opposite to the predetermined
direction, since the eccentric direction of the fiber core
is reversed with respect to the center of the ferrule 403
in the case of the single core optical fiber, there exists
a problem in that the eccentricity of fiber axis changes as
compared with when the two fibers are coupled under the
predetermined (selected) coupling conditions and therefore
the coupling loss increases. Further, where one of the
optical plug connectors 401 is inserted reversely, there
inevitably exists some insertion holes 422 into which other
plug connectors will not be inserted.
The fifth feature of the optical connector according
to the present invention is to provide an optical connector
locating structure in which the optical connector plugs can
be inserted only in a predetermined direction or
orientation into a connector housing at which a plurality
of optical connector plugs are mounted at the highest
possible mounting density.
A preferred embodiment of the present invention will
be explained with reference to the attached drawings.
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Fig. 27 is a perspective view showing the optical
connector according to the present invention, Fig. 28(a) is
a front view showing the optical connector plug, Fig. 28(b)
and 28(d) are side views thereof, Fig. 28(c) is a side
cross-sectional view thereof, Fig. 29 is a side
cross-sectional view showing the state where the optical
connector plug is inserted into the connector housing, and
Fig. 30 is a front view showing the connector housing.
As shown in these drawings, an optical connector plug
411 comprises a plug housing 414 for supporting a ferrule
413 into which an optical fiber 412 is bonded, a spring 415
for urging the ferrule 413 and a knob 417 for locking and
unlocking the optical connector plug to and from the
connector housing 416, in the same way as in the prior-art
F04 optical connector. The connector plug 411 is square in
cross section thereof and formed with two axially extending
grooves 418 on the opposing side surfaces of the knob 417
and with a projection portion 419 axially extending on
another side surface thereof.
The groove 418 is formed on each of the two opposing
side surfaces of the knob 417 so as to be a little offset
from the middle portion thereof, in such a way that the
width Wl of one inclined projection portion 420a is wider
than that W2 of the other inclined projection portion 420b.
Therefore, both the opposing side surfaces in which the
grooves 418 are formed, respectively are symmetrical with
respect to a plane passing through the center of the
ferrule 413 in parallel to both the side surfaces of the
square plug 411 and through the middle portion of the
projection portion 419, but asymmetrical with respect to a
center of the axis of the ferrule 413.
On the other hand, in the connector housing 416, the
housing body 422 is formed with a plurality of insertion
holes 416a into which optical connector plugs 411 are
inserted, and with projections 424 and grooves 425 fitted
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to the grooves 418 and the projection 419 of the optical
connector plugs 411, respectively.
Further, cylindrical hollow alignment sleeves 425 into
each of which the ferrule 413 of the optical connector plug
411 is inserted are provided within the insertion holes
416a of the connector housing 416. Further, two elastic
deformable engage arms 426 each having an engage claw 426a
are formed within the connector housing 416 so as to be
engageable with the recessed portion 418a of the groove 418
of the optical connector plug 411. Further, the engage arm
426 is formed with side projection portions 426b (only one
is shown) brought into contact with the inclined projection
portions 420a and 420b for locking and unlocking function,
when the optical connector plug 411 is inserted into or
removed from the connector housing 416. Therefore, when
the optical connector 411 is inserted into the insertion
hole 416a of the connector housing 416, the grooves 418
formed in both the surfaces of the knob 417 are engaged
with the projections 42~ formed within the insertion holes
416a, so that the claw portions 426a are engaged with the
recessed portion 418a of the grooves 418 and further the
projections 424 are engaged deep with the grooves 418 to
engage the optical connector plug 411 with the connector
housing 416 as shown in Fig. 29.
Fig. 30 shows an example of the connector housing 416
for supporting a plurality of optical connector plugs, in
which four insertion holes 416a are formed as four parts I,
II, III and IV.
In the above-mentioned structure between the optical
connector plug 411 and the connector housing 416, even when
only a single optical connector plug is inserted into a
part III, for instance as shown in Fig. 31(a), it is
impossible to insert the optical connector plug 411 in the
reverse direction, because the groove 418 between the
projections 420a and 420b having two different widths W1
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and W2 of the optical connector plug 411 will not be
engaged with the projections 424 of the connector housing
416 with an interference 430 (Wl-W2) between the two.
Therefore, it is possible to prevent the optical
connector plug 411 from being inserted into the connector
housing 416 erroneously even when the optical connectors
411 are arranged at the highest possible mounting density.
Further, in the above embodiment, the asymmetry with
respect to the axial center of the optical connector plug
411 is realized by offsetting the grooves 418 from the
longitudinal center of the knobs 417 to obtain two
different widths W1 > W2 of the two projections 420a and
420b. Without being limited thereto, however, it is
possible to obtain the same effect by forming the two
opposing surface shapes in symmetry with respect to a plane
passing through the axial center of the connector plug and
parallel to the two opposing surfaces but in asymmetry with
respect to an axial center of the connector plug.
As described above, in the optical connector plug
locating structure according to the present invention,
since the two opposing surfaces are symmetrical in shape
with respect to a plane passing through the axial center of
the connector plug and a middle portion of the plug
projection but asymmetrical in shape with respect to the
axial center of the connector plug, it is possible to
prevent the optical connector plugs from being inserted
into the connector housing erroneously in the reverse
direction when the optical connector plugs are mounted at
the highest possible arrangement density.
Therefore, the structure of the present invention is
advantageous in particular when applied to a plug-in
optical connector for allowing a plurality of fibers to be
connected simultaneously, because the highest possible
mounting density is required for the plug-in optical
connector.
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The six features of the present invention relates to
an optical connector jack used for a plug-jack optical
connector for removably connecting an optical fiber.
Prior to the description of the optical connector, a
reference will be made to a prior-art optical connector
with reference to the attached drawing.
The prior-art optical connector is classified into a
plug-adapter-plug (PAP) optical connector and a plug-jack
(PJ) optical connector. The PAP optical connector is
composed of two optical connector plugs for supporting two
ferrules, respectively to each of which an optical fiber
end is connected, and an optical adapter engaged with these
plugs so as to support two alignment sleeves to each of
which the ferrule is inserted. Further, the PJ optical
~ connector is composed of an optical connector plug for
supporting the ferrule to which an end of the optical fiber
is connected, and an optical connector jack engaged with
the optical connector plug and supporting the ferrule to
which an optical fiber end is connected and the alignment
sleeve into which the ferrule is inserted.
In various optical devices, however, the P-J optical
connectors are widely used. Fig. 32 shows a prior-art P-J
optical connector applied to a plug-in optical connector
disclosed in U.S. Patent No. 4,895,425. This optical
connector includes a package connector 506 attached to a
package board 508 and a back panel connector 507 attached
to a back panel 509. That is, an optical connector plug
505 is attached to the back panel connector 507. The
connector plug 505 supports a ferrule 503A to which an
optical fiber end is connected. An optical connector jack
501 is attached to the package connector 506. The optical
connector jack 501 is constructed so as to be engaged with
the optical connector plug 505. Within a jack body 502 of
the optical connector jack 501, an alignment sleeve 504, a
ferrule 503 and a housing 521 for supporting these elements
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503 and 504 are housed. The ferrule 503 is inserted into
the alignment sleeve 504 and an optical fiber end is
connected to the ferrule 503.
Therefore, the two optical fibers are connected by
locating the optical connector jack 501 and the optical
connector plug 505, inserting the ferrule 503A within the
optical connector plug 505 into the alignment sleeve 504
within the optical connector jack 501, opposing two ferrule
end surfaces 531 coaxially, and pushing these two ferrules
against each other by a spring 528.
Here, since not only the ferrule 503 but also the
ferrule 503A are inserted into the alignment sleeve 504,
the ferrule end surface can be located roughly at the
center of the alignment sleeve 504. In other words, the
end surface 531 of the ferrule 503 is located inside the
alignment sleeve 504, that is, deep within the optical
connector jack 501.
In the above-mentioned optical fiber connection by the
optical connector, when dust or wear chip attached onto the
inner surface of the ferrule end surface 531 and the
alignment sleeve 504, the connection characteristics of the
optical fibers are deteriorated due to an increase in
connection loss or return loss. Therefore, it is necessary
to periodically clean the ferrule end surface 531 and the
alignment sleeve 504.
In the prior-art optical connector jack, however,
since the ferrule end surface 531 and the alignment sleeve
504 are located deep within the jack from the structural
standpoint, it has been difficult to clean the ferrule end
surface 531 located deep within the alignment sleeve 504 by
inserting a cleaning element (e.g. a cotton swab) into a
narrow alignment sleeve 504.
With the development of optical communications
technology, since the optical connectors are reduced in
size more and more for higher arrangement density, it is
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CA 02354172 2001-08-08
indispensable to reduce the length and the diameter of the
ferrules 503 and 503A and the alignment sleeve 504.
In the prior-art optical connector jack, however, when
the inner diameter of the alignment sleeve 504 is further
reduced, it is impossible to insert a cotton swab into the
sleeve 504, so that it is impossible to clean the ferrule
end surface 531 and the alignment sleeve inner surface.
Further, in the optical connector, whenever the
connectors are connected to or disconnected from each
other, wear chip is produced due to friction between the
ferrule 503 or 503A and the alignment sleeve 504.
In case the wear chip sticks onto the ferrule end
surface 531, since the connection loss or the reflection
thereof increase, the connection characteristics
deteriorate. To reduce the wear chip, recently excellent
abrasion resistant ceramics such as Zirconia ceramics are
used as the material for the alignment sleeve. In this
case, however, since the alignment sleeve made of ceramics
is brittle and therefore easili! broken when a torsional
stress beyond a predetermined value is applied to the
alignment sleeve by mistake, the alignment sleeve must be
easily replaced with a new one.
In the prior-art optical connector jack, however,
since the alignment sleeve 504 cannot be easily removed out
of the optical connector jack, in case the alignment sleeve
504 is broken, it h.as been difficult or impossible to
remove the alignment sleeve 504 from the end surface (511)
side for replacement.
As described above, in the prior-art P-J optical
connector, since the alignment sleeve is supported within
the optical connector jack, there exist problems in that it
is difficult to clean the ferrule end surface and the
alignment sleeve inner surface and further difficult to
replace the broken alignment sleeve with a new one.
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. CA 02354172 2001-08-08
The above-mentioned problems with difficulty in
ferrule cleaning and alignment sleeve replacement are
serious because the optical connectors are miniaturized at
higher arrangement density by reducing the diameters of the
ferrule and the alignment sleeve or by making the alignment
sleeve of ceramics.
The sixth feature of the optical connector according
to the present invention is to provide an optical connector
jack easy to clean the ferrule and the alignment sleeve and
further easy to replace the alignment sleeve with a new
one.
An embodiment of the present invention will be
described hereinbelow with reference to the attached
drawings.
rigs. 33 (a), (b) and (c) show an embodiment of the
present invention. An optical connector jack 501 includes
a jack body 502 within which a rear housing 521 and a front
housing 522 are separatably provided. The rear housing 521
and the front housing 522 are both formed into cylindrical
shape. The rear housing 521 is formed with a female
threaded portion 525 on a front inner circumference thereof
as engage means. The front housing 522 is formed with a
male threaded portion 523 on a rear outer circumference
thereof as engage means. Therefore, when the female
threaded portions 525 are engaged with the male threaded
portion 523, the front housing 522 and the rear housing 521
are both engaged with each other. Further, when unscrewed,
the engagement between the two can be released.
An alignment sleeve 504 is loosely supported within
the front housing 522. To prevent removal of the alignment
sleeve 504 in the rearward direction, the front housing 522
is formed with a shoulder portion 524 with a smaller inner
diameter at the rear side thereof.
The rear housing 521 is formed with a shoulder portion
with a smaller inner diameter at the rear side thereof to
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CA 02354172 2001-08-08
support the ferrule 503 therewithin. A ferrule 503 is
inserted into the front housing 522 and the alignment
sleeve 504. An end of an optical fiber 530 is connected to
the ferrule 503. Further, the end surface 531 of the
ferrule 503 is located frontward from the engagement
position between the front housing 522 and the rear housing
521. In other words a housing is engageably or
disengageably divided into the front housing 522 and the
rear housing 521 at a position rearward from the ferrule
end portion 531.
Further, a sprig 528 is provided on the rear side of
the ferrule 503 to push the ferrule end surface 531 against
another ferrule end surface of an optical connector plug
(not shown) within the alignment sleeve 504.
In the optical connector jack of the present
invention, the structure is such that the front housing 522
can be easily removed from the rear housing 521 by
loosening the engagement between the female threaded
portion 525 and the male threaded portion 523 as shown in
Figs. 33 (b) and (c). Further, when the female threaded
portion 525 and the male threaded portion 523 are fastened
each other, the rear housing 521 and the front housing 522
can be securely engaged with each other.
Therefore, when the front housing 522 is removed from
the rear housing 521 of the optical connector jack 501,
since the alignment sleeve 504 is loosely supported within
the front housing 522, it is possible to easily remove the
alignment sleeve 504 from the front housing 522 for
replacement with a new one. .
Further, when the front housing 522 is removed from
the rear housing 521, since the end surface 531 of the
.ferrule 503 projects from the rear housing 521, it is
possible to easily clean the ferrule 503 by use of a cotton
swab, for instance without inserting the cotton swab into
the alignment sleeve 504 with a small inner diameter.
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A second embodiment of the present invention will be
described in detail with reference to Figs. 35 (a) and (b).
In this embodiment, a frictional force is utilized as
engage means between the rear housing 521 and the front
housing 522.
That is, the front housing 526 has an outer friction
engage portion 526 at the rear outer circumferential
surface thereof, and the rear housing 521 has an
inner-friction engage portion 527 (whose inner diameter is
a little smaller than that of the outer frictional engage
- portion 526) at the front inner circumferential surface
thereof. Therefore, the two friction engage portions 526
. and 527 are fitted to each other for frictional connection.
The construction other than the above is the same as in the
first embodiment.
Therefore, when the front housing 522 is removed from
the rear housing 521 against the frictional force between
the two friction engagement portions 526 and 527, the
alignment sleeve 504 supported within the front housing 522
can be easily replaced with a new one, and further the end
surface 531 of the ferrule 503 projecting from the rear
.housing 521 can be easily cleaned by a cotton swab, for
instance.
Further, in the above first and second embodiments,
the shoulder portion 524 of the front housing 522 is formed
integral with the front housing 522. Without being limited
thereto, however, it is also possible to provide another
ring 528 within the front housing 522 in place of the
shoulder portion 524, as shown in Fig. 35. In this case,
the ring 528 is friction fitted into the front housing 522
by determining the outer diameter thereof to be a little
larger than the inner diameter of the front housing 522.
Since the ring 528 also can be removed, it is possible to
more easily replace the alignment sleeve 504 with a new
one.
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Figs. 36 (a), (b) and (c), Fig. 37 and Fig. 38 show a
third embodiment of the present invention.
This embodiment relates to a plug-in optical connector
by which a plurality of optical fibers can be connector or
disconnected simultaneously.
As shown in Figs. 36 (a), (b) and (c), this plug-in
optical connector is composed of a package connector 506
attached to a package board 508 and a back panel connector
507 attached to the back panel 509. A plurality of optical
connector jacks 501 are attached to the package connector
506, and a plurality of optical connector plugs 505 coupled
with the jacks 501 are attached to the back panel connector
507.
As shown in Figs. 37(a) and 37(b), the optical
connector jack 501 is composed of the jack body 502, the
rear housing 521, and the front housing 522. The rear
housing 521 is attached to the front portion of the jack
body 502. The front housing 522 is friction fitted to the
front portion of the rear housing 521 so as to be engaged
with and disengaged from each other. Within the
cylindrical front housing 522, the alignment sleeve 504 is
supported. Within the rear housing 521, the ferrule 503 is
supported. The ferrule 503 i's inserted into the alignment
sleeve 504. The ferrule end surface 531 is located
frontward from the engagement position between the rear
housing 521 and the front housing 522. A small-diameter
portion 524 is formed at the rear inner circumference of
the front housing 522 to prevent the alignment sleeve 504
from being removed. The spring 528 is provided within the
rear housing 521 to urge the ferrule 503 frontward.
Therefore, when the package connector 506 and the back
panel connector 507 are connected by locating the optical
connector jacks 501 and the optical connector plugs 505 as
shown in Fig. 36 (b), the ferrule 503A can be inserted into
the alignment sleeve 504, so that the optical fibers can be
coupled.
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Further, as shown in Fig. 38, when the front housing
522 is removed from the rear housing 521 against the
frictional force, the alignment sleeve 504 supported within
the front housing 522 can be easily replaced with a new
one, and further the end surface 531 of the ferrule 503
projecting from the rear housing 521 can be easily cleaned
by use of a cotton swab, for instance.
Further, in the above embodiments, although the front
and rear housings can be engaged or disengaged by means of
threaded portions or friction surface portions. Without
being limited thereto, it is possible to adapt other means
for securely engage and easily disengage these two housings
with and from each other.
As described above, in the optical connector jack
according to the present invention, since the housing is
divided into the front and rear housings, when the front
housing is removed from the rear housing, the alignment
sleeve can be replaced with a new one. In this case, since
the ferrule end surface projects frem the rear housing, the
ferrule end surface can be easily cleaned. Therefore, in
case the alignment sleeve is broken, the broken alignment
sleeve can be replaced; and if the optical connector jack
is deteriorated in the connection loss, the connection loss
can be restored by cleaning the ferrule end surface.
In particular, when the diameters of the ferrule and
the alignment sleeve are reduced, it is possible to
facilitate maintenance of the optical connector jack.
Therefore, when the characteristics of the optical
connector jacks are deteriorated, it is possible to restore
the jack connection characteristics by cleaning the
ferrules or by replacing the alignment sleeves, without
replacing the overall package board.
An embodiment of the plug-in optical connector to
which the first to fifth futures according to the present
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CA 02354172 2001-08-08
invention are realized will be described hereinbelow with
reference to Figs. 39 to 43.
In this embodiment, the first connector 30 is attached
to the package board 1 and the second connector 31 is
attached to the back panel 5, being different from the
embodiment shown in Figs. 2 and 3.
Figs. 39(a) to (d) are left side, partially broken
cross-sectional front, right side, and top views,
respectively showing the first connector. Figs. 40(a) and
(b) are enlarged cross-sectional views showing the
essential portions of the first connector, in which Fig.
40(a) is a transversal cross-sectional view and Fig. 40(b)
is a longitudinal cross-sectional view thereof. Figs.
41(a) to (d) are left side, partially broken
cross-sectional front, right side, and top views,
respectively showing the second connector. Figs. 42(a) and
(b) are enlarged cross-sectional views showing the
essential portions of the second connector, in which Fig.
42(a) is a transversal cross-sectional view and Fig. 42(b)
is a longitudinal cross-sectional view thereof. Fig. 43 is
a plan view showing a back panel.
With reference to Figs. 39(a) to (d), the first
connector 30 having the first housing 33 is fixed to the
package board 1 with screws 55. The first housing 33 is
formed with the second elastic engage levers 40 on the
upper and lower surfaces thereof. In the same way as shown
in Fig. 2, the second elastic engage lever 40 is formed
with the claw portion 40a and two side projection portions
40b. Further, the first housing 33 is also formed with the
first release members 41 having the inclined surfaces 41a.
Within the first housing 33, there are provided
partitions 632 for supporting the first optical connector
element (pl.ug) 32 having a ferrule 201 therebetween as
shown in Fig. 40(a), and elastic arms 357A each having a
claw portion 35~3n (as shown in f~'ig. 2~1) for holding the
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first optical connector element 32 therebetween. Further,
the first housing 33 is formed with crosspiece members 631
connected to the partitions 632 to hold the front housings
(sleeve holders) 522 (as shown in Fig. 33) into each of
which the alignment sleeve 504 is inserted. Further, in
Fig. 39(b), chamfered insertion guide corners 633 are
formed in the first housing 30. In Figs. 40(a) and (b),
two engage projections 360 (as shown in Fig. 24) are formed
in each first optical connector element 32.
With reference to Figs. 41(a) to (d), the second
connector 31 floatingly supported on the back panel 5 is
composed of the second housing 34, the third housing 36 and
a reverse side housing 641.
As shown in Figs. 41(d) and 43, a roughly square
mounting opening 659 is formed in the pack panel 5. Near
the four corners of the mounting opening 659, four screw
supporting slots 691 are formed. Each slot 691 is formed
with two widths wider than the diameter of floating screws
55B in both the horizontal and ~.rertical directions. The
second connector 31 is floatingly supported in such a way
that the back panel 5 is sandwiched between the second
housing 34 and the reverse side housing 641 with the
floating axles (55B) and screws 55C. Therefore, the second
connector 31 is floatingly supported by the back panel 5
with a clearance between the diameter of the floating axles
55B and the width of the screw supporting slots 691, and
the third housing 36 is slidably supported within both the
second housing 34 and the reverse side housing 641 so as to
pass through the mounting opening 659.
The third housing 36 is formed with the first elastic
engage levers 38 and the second projections 39. As shown
in Fig. 42(a), when the second housing 34 is not engaged
with the first housing 33, the LirsC elastic engage levers
38 of the third housing 36 are engaged with the first
projections 37 of Lhc Second hou3ing 3~1 in t:hc same way as
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CA 02354172 2001-08-08
shown in Fig. 3(a). On the other hand, when the second
housing 34 is engaged with the first housing 33, the first
elastic engage levers 38 of the third housing 36 are
disengaged from the first projections 37 of the second
housing 34, so that the third housing 36 is slidable within
the second housing 34 in the horizontal direction in Fig.
41(b). To allow the third housing 36 to be slidable, a
space SP is formed between the second housing 34 and the
reverse side housing 641.
The second projections 39 of the third housing 36 are
engaged with the claw portions 40a of the second elastic
engage levers 40 of the first housing 33, when the second
housing 34 is connected to the first housing 33. To
smoothly engage or disengage the second housing 34 with or
from the first housing 33, the second release members 42
are formed in the second housing 34.
Within the third housing 36, there are provided
partitions 642 for supporting the second optical connector
element (jack) 35 having a ferrule 204 therebetween as
shown in Fig. 42(a), and elastic arms 357B each having a
claw portion 358B (as shown in Fig. 24) for locking the
second optical connector element 35 therebetween.
Further, the second housing 34 is formed with the
second release member 42 having two inclined surfaces 42a
and 42c and a flat surface 42b.
Within the third housing 36, the second optical
connector element 35 is engaged by the second elastic arms
357B. The third housing 36 is engaged with the second
housing 34 by the engagement between the first elastic
engage levers 38 of the third housing 36 and the first
projection portions 37 of the second housing 34.
As already explained, the firs!: connector 30 is fixed
to the package board 1 with screws 55. Within the first
housing 33, the first optical connector element 32 is held
by Lhe elastic a~r.ms 357n. In front of the first optical
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connector element 32, the front housing (sleeve holder) 522
is supported. The alignment sleeve 504 is inserted into
the front housing 522 to align the ferrule 201 of the first
optical connector element 32 with the ferrule 204 of the
second optical connector element 35.
At the front end of the first housing 33, the first
inclined surfaces 41a of the first release members 41 are
formed to release the engagement between the first elastic
engage levers 38 of the third housing 36 and the first
projection portions 37 of the second housing 34 when the
second connector 31 is connected to the first connector 30.
In the second housing 34 of the second connector 31,
the second release members 42, each having the two
inclined surfaces 42a and 42c and the flat surface 42b are
formed. In the third housing 36, the second projection
portions 39 are formed.
On the other hand, within the first housing 33 of the
first connector 30, the second elastic engage levers 40
each having the claw portion 40a and two side projections
40b are formed so that the two side projections 40b are
brought into contact with the inclined surfaces 42b into
engagement with the second projections 39 of the third
housing 36 when the second connector 31 is connected to the
first connector 30.
Further, the first housing 33 is formed with chamfered
corner guide portions 633 and the second housing 34 is
formed with the similar chamfered corner guide portions 643
at the end thereof, respectively to allow the two connector
housings to be easily connected to each other.
The engage and disengage operation of_ these connectors
is as follows:
Engagement
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CA 02354172 2001-08-08
(1) The second housing 34 and the third housing 36 are
aligned with the first housing 33,
(2) the side projections 40b of the second elastic engage
levers 40 of the first housing 33 are brought into contact
with the inclined surfaces 42c of the second release member
42 of the second housing 34 to deform the second elastic
engage levers 40;
(3) the ferrules 204 of the second optical connector
elements 35 are aligned with the alignment sleeves 504;
(4) the ferrules 204 of the second optical connector
elements 35 are brought into contact with the ferrules 201
of the first optical connector elements 32;
(5) the second elastic engage levers 40 of the first
housing 33 are engaged with the second projections 39 of
the third housing 36;
(6) the engagement between the first projections 37 of the
second housing 34 and the first elastic engage levers 38 of
the third housing 36 is released; and
(7) the third housing 36 is connected with the first
housing 33 so as to be slidable within the second housing
34, thus completing the coupling between the first
connector 30 and the second connector 31.
Disengagement
(1) the first housing 33 and the third housing 36 are slid
together within the second housing 34;
(2) the Lirst elastic engage levers 3F3 oF_ the third
housing 36 are engaged with the first projections 37 of the
second housing 34;
(3) the side projections 40b of the second elastic engage
levers 40 of the first housing 33 are brought into contact
with the inclined surfaces 42a oI the secor7d re~.ease member
42 of the second housing 34, so Lhal, l.hc sac:oncl ~lasti.c
er~gagc levcr3 X10 arc d i.~cng~gcd f rom ~hc _~,cconc7 fro ject i ons
39 of the third housing 36;
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CA 02354172 2001-08-08
(4) the ferrules 204 of the second optical connector
elements 35 are moved away from the ferrules 201 of the
first optical connector elements 32;
(5) the ferrules 204 of the second optical connector
elements 35 are removed from the alignment sleeve 504;
(6) the side projections 40b of the second elastic engage
levers 40 are moved away from the inclined surfaces 42c of
the second release members 42 of the second housing 34; and
(7) the second housing 34 and the third housing 36 are
removed together from the first housing 33, thus completing
the decoupling between the first connector 30 and the
second connector 31.
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