Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
MULTI FIBER OPTICAL INTERCONNECT SYSTEM, WITH PUSH-PUSH TYPE
INSERTION/WITHDRAWAL MECHANISM, MT-TYPE CONNECTOR AND
SHUTTERED ADAPTER AND METHOD FOR USING SAME
This application claims priority to U.S. patent application Serial No.
11/166,556,
filed June 24, 2005, which is a continuation-in-part application of
application to U.S.
patent application Serial No. 11,155,360 entitled Ultra -Small, Form Factor
Single Fiber
Optical Interconnect System, With Push-Push Type Insertion/Withdrawal
Mechanism And
Shuttered Modular Connector And Shuttered Adapter And Method For Using Same
and
filed June 17, 2005, which is a continuation-in-part of Serial No. 11/036,306
entitled
Ultra-Small, Forin Factor Single Fiber Optical Interconnect System With
Shuttered Connector
and Shuttered Adapter and filed on January 12, 2005.
TECHNICAL FIELD
The invention relates to fiber optics or fiber optical interconnect systems
and, more
particularly, to a multi-fiber optic interconnect system consisting of fiber
connectors and
corresponding adapters for the precise end-to-end mating of fiber optic
cables. More
particularly, the invention further relates to an MT-type interconnect system
consisting of
fiber optic connectors and corresponding adapters with a "push-push"
insertion/withdrawal mechanism and a method for using the same.
BACKGROUND ART
In the fiber optics field, the need frequently arises to connect or disconnect
connectors and adapters in both single channel and multiple channel connectors
and
adapters. The invention herein disclosed applies primarily to multiple fiber
applications.
There is a continuously increasing demand for higher density interconnect
systems in fiber
optics applications, especially in those cases where multiple fiber connectors
or multiple
fiber ferrules are not conveniently reachable due to small size, routing or
other
1
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
considerations.
In the fiber optics field, the need frequently arises to transfer light from
one fiber to
another either permanently or temporarily. Optical connector plugs or
connectors are one of
the solutions used for this purpose. Fibers terminated with optical connector
plugs can be
coupled together and disconnected when necessary, either to end the connection
or to route
the light to a different fiber. Optical connector plugs can be of the single
or multiple fiber
variety. Single fiber connector plugs (simplex connector plugs) provide the
connection of
only one fiber to another single fiber. In multiple fiber connector plugs,
several fibers are
simultaneously coupled with another set of similar fibers.
Traditionally, in multi-fiber connectors, the connection is achieved by the
use of MT-
type ferrules. The ferrules, which may be manufactured mostly from plastic,
have a number
of channels of a diameter slightly larger than the optical fiber. In use, the
optical fibers are
inserted into the channels and maintained fixed therein by the use of
adhesives such as, but
not limited to, epoxy, or mechanical clamping. The ends of the fibers are
preferably made to
be flat or protrude slightly from the end surfaces of the ferrule and are then
terminated,
generally by a polishing procedure or other means that provides a very smooth
surface of
optical quality.
Two connectors may be mated using an adapter. Each connector preferably
comprises the ferrule and a ferrule holder. One of the two mated connectors
usually has a
ferrule with a pair of alignment pins, while the other connector has a ferrule
with a pair of
alignment holes. Modern fiber optic connectors usually have a spring mechanism
that pushes
the ferrules towards one another with a controlled force in order to achieve
physical contact
of both of the ferrules' ends, thereby improving the optical performance of
the connection.
The termination or polishing of the fiber ends is a very involved and delicate
procedure which results in the fiber position being either slightly below or
above the ferrule
2
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
end-face surface. The protrusion of the fibers from the ferrule end has to be
controlled to very
tight tolerances in order to avoid damage of the fiber ends when in physical
contact. The
pressure between fibers has to be kept in a narrow range in order to keep the
glass in its
elastic region and thereby prevent fiber rupture as well as preventing the
movement of the
fibers inside the ferrule channels (pistoning) when the two connectors are
mated. It is also
very important to obtain a very smooth surface free of scratches and other
defects, especially
in the central core section of the fiber where the light travels. In
particular, since ferrule ends
and fibers are preferably polished together, it is necessary to prevent
released ferrule material
from damaging the fiber ends during this procedure.
Keeping fiber optic connector plugs free from contaminants such as dirt or
dust is
also very important. Dirt or dust on fiber ends can scatter or absorb light,
causing excessive
loss of signal and corresponding poor system performance. Presence of
contaminants inside
the connector plug could cause misalignment with similar consequences.
Likewise, because
of the intensity of the light being transferred, it is important to shelter
users from unintended
viewing thereof, so as to prevent eye injury.
There is also a continuously increasing demand for higher density interconnect
systems in fiber optics applications. The introduction by the present
invention of a multi-fiber
connector with the standard MT type ferrule has resulted in a small multi-
fiber
connector/adapter system with a push-push mechanism that allows for very high
density
configurations.
SUMMARY OF INVENTION
One object of the present invention is to provide a small footprint, multi-
fiber
optical interconnect system suitable for high density applications which has a
push-push
mechanism for quick and convenient connect/disconnect operation in an
environment
3
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
where it is difficult to reach and activate a conventional fiber optical
interconnect system.
One embodiment of the system disclosed herein comprises two miniature
connectors and an
adapter. The miniature connectors can handle multi-channel MT standard
ferrules so as to
enable the acceptance of bare and cabled fiber optics. The push-push mechanism
is
controlled by the connectors' internal springs as well as by two identical
springs in the
adapter, and works automatically when connectors are connected or disconnected
to or
from the interior of the adapter. In this version of the invention, pushing a
first time on the
connector connects the connector to the adapter, while pushing on the
connector a second
time serves to disconnect the connector from the adapter.
The connectors can handle standard MT ferrules in an embodiment to accept bare
and
cabled fiber optics. It is appreciated that the ferrules may be manufactured
mostly from
plastic, or from other materials including, but not limited to, ceramics,
metal and glass and
not depart from the scope of the present invention. In this version of the
invention, dust and
laser protection shutters are located at both sides of the adapter. The
shutters are preferably
controlled by a spring mechanism, and open and close automatically when
connectors and
adapters are attached or separated. Latches are also included that keep the
connection
securely together, and a release mechanism that actively uncouples the
connector and adapter
is included in the body of the connector. The adapter also is preferably made
of a material or
coated so as to provide for protection from EMI (electromagnetic
interference).
The adapter is designed to provide sufficient freedom to enable alignment of
the
ferrules during the mating or connecting process. Ideally, the goal is to
provide for a floating
connection of the ferrules within the adapter housing. This also is true for
connectors using
angle-polished ferrules which can have ends polished to a variety of angles
including a
preferred embodiment of about 8 degrees relative to the optical axis. The
angled ends of the
ferrules are the mating surfaces of the two connectors in face-to-face
fashion.
4
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
In a preferred embodiment of the shuttered adapter version of the invention,
an
adapter shutter mechanism comprises a serpentine-shaped spring acting upon
cams of shutter
doors that are mounted to rotate about a vertical axis at each end of the
adapter. Other types
of springs and means for biasing the shutter doors into a normally closed
position, such as,
but not limited to, spring clips, coil springs, torsion springs and elastic
materials, should be
considered as being within the scope of this invention. When the adapter does
not have a
connector inserted in an open end, the serpentine-spring pushes against the
cam of the shutter
door at the open end so as to urge it into the closed position. When the
connector is pushed
into the open end of the adapter, the front of the connector pushes against
the adapter shutter
door and overcomes the force of the serpentine-spring on the adapter shutter
door so as to
automatically move the shutter door into the open position.
Spring loading of the ferrule inside of the connector is preferably provided
by two coil
springs serving to bias the ferrule forward within the connector housing;
however, other types
of springs and means for biasing the ferrule forward, such as, but not limited
to, spring clips,
torsion springs and elastic materials, should be considered as being within
the scope of this
invention.
Numerous other features and advantages of the present invention will become
apparent from the following detailed description of the invention, the
accompanying
drawings and the appended claims, wherein like reference numerals refer to
like parts.
BRIEF DESCRIPTION OF DRAWINGS
The design of the system can be better understood by following the description
of
the drawings set forth herein. A brief description of each figure is included
here.
Figure 1 shows an overall perspective view of the miniature connector/adapter
system
of the present invention.
5
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
Figure 2 is a perspective view of the miniature connector shown in Figure 1.
Figure 3 is a partially exploded view of the miniature connector shown in
Figure 2.
Figure 4 is a perspective view of the adapter for the miniature connector of
Figure 3
showing the openings at each end for receiving a connector in each opening.
Figure 5 is an exploded perspective view of the adapter of Figure 4
illustrating the
shutters with their respective cams, the serpentine-spring normally contained
therein and the
outer shell removed.
Figure 6a is a perspective view of the bottom of the flipper of the present
invention.
Figure 6b is a bottom plan view of the flipper of Figure 6a.
Figures 7a-7f are schematic views which show different positions of the
flipper of
the adapter and dual pin of the connector during the push-push insertion and
withdrawal
actions.
DETAILED DESCRIPTION OF DRAWINGS
While this invention is susceptible of embodiment in many different forms,
there is
shown in the drawings and will herein be described in detail several specific
embodiments,
with the understanding that the present disclosure is to be considered merely
an
exemplification of the principles of the invention and the application is
limited only to the
appended claims.
Referring to Figs. 1 through 7, there is shown one embodiment of a miniature
MT
type connector/adapter system with a push-push insertion/withdrawal mechanism.
The
miniature MT type connector/adapter system includes a male connector 1, an
adapter 2, and a
female connector 3.
In Figure 1, male connector 1 is shown as a structure designed for fiber optic
ribbon
cable with a straight strain relief boot 4 in the position before being
inserted into adapter 2,
and female connector 3 is shown as having a small strain relief boot 6
designed for bare
6
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
ribbon when it is fully inserted into adapter 2 and fixed in the mated
condition. Any other
coinbinations of connector types with different gender, different boots,
ferrule mode types
(single and multi mode), number of channels, etc. are possible and should be
considered
within the scope of present invention.
Figure 2 is an isometric view of the male connector 1 of Fig.1 showing a
miniature
MT-type ferrule 7 with two pins 8 which makes it a male connector. It also
shows front
housing 9 with two latch openings 10 (only one opening is visible) and a dual
pin 11. In
addition, it shows rear housing 12 with pushing tab 13 and straight strain
relief boot 4.
Different configurations of the boot (for example 90 , 60 , 45 , etc.) should
be considered in
the scope of the present invention.
Figure 3 is a partially exploded view of the connector 1 of Fig. 2. It shows
MT ferrule
7 with internal boot 14 which is inserted into the ferrule 7 from the rear. It
also shows
preassembled pin holder 15 and two alignment pins 16. It should be understood
that pin
holder 15 is preassembled with pins 16 only in the male configuration of the
connector 1. If
connector I should be assembled as a female configuration then alignment pins
16 are not
installed.
Pin holder 15 (with or without alignment pins 16) pushes or biases ferrule 7
straight
ahead by two connector springs 17. Rear housing 18 has two nests for springs
17 so they can
push pin holder 15 and, consequently, ferrule 7 up to the stop (not shown)
inside of the
connector housing 9. Rear housing 18 is preferably secured inside of the
connector housing 9
by two latches 19 that snap into two openings 10 in the connector housing 9
(only one latch
and one opening are shown). Once connected, ferrule 7 is spring loaded with a
standard force
designed for optimal contact between fibers. Rear housing 18 also has a tab 20
which is used
for pushing the male connector 1 by pen or stylus for insertion or withdrawal
when density
does not allow human fingers to do that job.
7
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
In addition, rear housing 18 preferably has a grooved tail 21 which serves,
together
with the oval crimp tubing 22, as a holding means for a fiber optic cable's
aramid yarn. It
should be understood that the bare ribbon version of the connector has a rear
housing 18
without the grooved tail and no crimp tubing is present.
The male connector I also preferably has a strain relief boot 4 (can be of
many
different configurations) for use with cables or a small boot 6 (as shown in
Fig. 1 for the
female connector 3) for use with bare ribbons.
Referring now to Figure 4, the adapter 2 is shown with two apertures 23 and 24
at its
ends, where two connectors 1 and/or 3 (See Figure 1) are intended to be
inserted. Figure 4
also shows outer shell 25 which serves as a holder (i.e., it holds the various
parts of the
adapter together) and a cover of all the internal parts as well as an EMI
shield. Adapter 2 also
preferably has two latches 5 (only upper latch is visible) and two stoppers 26
(only upper
stopper is visible) that are designed to assist in mounting the adapter on a
panel (not shown)
having a particular thickness. While the adapter is shown as being flangeless,
it is
appreciated that it may be flanged and not depart from the scope of the
present invention.
Figure 5 shows an exploded view of the push-push adapter 2 (see Fig. 4). In
this
view, two push-push mechanisms 27 are shown near each of the apertures 23 and
24.
Each mechanism 27 consists of triple prong spring clip 28, flipper 29, and
nest 30, which
serves as a vertical axis about which the flipper 29 rotates or pivots. Also
shown in
Figure 5 a re dual shutter mechanism 31 a nd its cover 32. Figure 5 also shows
the
serpentine-shaped spring 33 which outwardly biases two cams 34, each of which
is
respectively attached to ends of vertically mounted internal shutters 35 and
36. Shutters in
this example each have a vertical axis of rotation. When connectors 1 are not
inserted into
the receiving apertures 23 and 24 of the adapter 2, spring-biased cams 34 are
pushed by
spring 33 and rotate so that the internal shutters 35 and 36 are in the closed
position to
8
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
provide protection against dust and otller contaminants, as well as to prevent
eye injuries due
to the intensity of the light being transferred. It is appreciated that the
connector may be a
male connector or a female connector and not depart from the scope of the
present invention.
Adapter also preferably contains a barrel containing an alignment sleeve (not
shown)
that can, to some extent, freely float inside of the barrel to assist in
optimally aligning two
ferrules being engaged in physical, end-to-end contact from two opposite sides
of the adapter
2.
It should be understood that dual pin 11 (shown on Fig. 2) is an integral part
of the
push-push mechanism 27, since this dual pin 11 serves as an actuator of the
mechanism
27. Each triple prong spring clip 28 has two side arms 37 that keep flipper 29
in the
middle position in line with the longitudinal axis of the adapter when the
push-push
mechanism 27 is not actuated. Triple prong spring clip 28 also has a
horizontally
positioned arm 39 that presses flipper 29 down in order to maintain its
constant contact
with dual pin 1 I(see Figure 2) while performing push-push action during
insertion and
withdrawal of the connector I into or out of the adapter 2. The insertion of
connectors 1
into this engaged and retained relationship with adapter 2 can be accomplished
by, among
other things, applying a longitudinal force to tab 13 (see Fig. 2) by using a
stylus, pen
point, paper clip end or the like.
Figures 6a and 6b show the flipper 29 in detail. Figure 6a is an isometric
view of
the bottom surface of the flipper 29, while Fig. 6b is a bottom plan view of
the flipper 29.
Figures 6a and 6b show that flipper 29 includes pin 40 providing a vertical
axis X about
which flipper 29 sw ings or pivots to the left and to the right during the
push-push
operation. Also shown are inclined cam surfaces 41 and 42 of projection 43 and
inclined
cain surface 44 of projection 45 which urge flipper 29 to swing to the left or
to the right
based on direct contact with dual pin l 1 of the connector 1, depending upon
whether dual
9
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
pin 11 (see Fig. 2) moves forward or backward respectively, during either the
insertion or
withdrawal operation.
As further shown in Fig. 7d, V-grooved surface 46 of projection 45 reliably
keeps
connector 1 in its mating position by holding squared portion of dual pin 11
with the
force of two internal connector springs (not shown). Cams 48 and 49 facilitate
the
flipper's 29 movement over the ramped edges 50 and 51 while the non-ramped
opposite
vertical sides of those edges 50 and 51 prevent flipper 29 from sliding back
and swinging
in the wrong direction during insertion or withdrawal of connector 1 into or
from adapter
2. As pushing force PPi continues to move left in Fig. 7b until it reaches
face 42 of
projection 43 which as shown in Fig. 7c, acts as a stop, while flipper 29
rotates upwardly
about axis X, which extends longitudinally through the center of pin 40, as
shown in Fig.
6a.
Figures 7a through 7f schematically show the interaction between flipper 29
and
dual pin 11 during insertion and withdrawal of connector 1 into or from
adapter 2. In
those diagrams, arrows FR and FL represent right and left biasing forces
created by two
side legs 37 of the spring clip 28 (see Fig. 5). Those forces tend to keep
flipper 29 in the
neutral position when inactive. Arrow PPi represents the insertion force when
connector
1 moves into the adapter 2 during the first "push" action. Arrow PC represents
the force
provided by two main connector springs (not shown in Fig. 7) which tends to
either: (1)
keep connector I in the mating position with the adapter 2 or, (2) push
connector 1 out of
the interior of adapter 2 after the second "push" action.
As shown in Fig. 7e, arrow PP2 represents a force of a second "push" action.
Each
of Figures 7a through 7f also has a virtual 2mm ruler which shows the relative
position of
flipper's 29 different elements described earlier and both square and circular
elements of
dual pin 11 during each step of the insertion and withdrawal processes.
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
In reference to Figures 7a through 7c, in operation, connection is initiated
by
pushing connector 1 in the direction of arrow Ppi of Figure 7a, until it is
received in
opening 24 of adapter 2 (Fig. 4). As square portion of pin 11 of connector 1
contacts and
then slides along in contact with surface 44, it is guided along ramped cam
surface 48
until it reaches the stopped position (Fig. 7c) by resting against angled
surface 42.
Further movement of connector 1 into the interior of adapter 2 is thus
prohibited.
Because flipper 29 is free to rotate about axis X, corresponding to pin 40 and
hole 30
(Fig. 5), the spring force FR provided by the side legs 37 of spring clip 28
is overcome and
flipper 29 rotates counterclockwise as viewed in Fig. 7b, until pin 11 reaches
the stop
position against surface 42 as shown in Fig. 7c. When connector 1 is released
and no
longer pushed inwardly into the interior of adapter 2, biasing forces F, and
Fi of spring
clip 28 tend to move flipper back to the center position of Fig. 7d, while
ramped cam
surface 48 tends to urge pin l 1 downwardly into the mated position so as to
abut surfaces
50 and 46 as shown in Fig. 7d by capturing square portion of pin 11 therein.
To unmate and withdraw connector I from adapter 2, connector I is again pushed
inwardly along the longitudinal axis as viewed in Figures 7e and 7f and
towards the
interior of adapter 2. Pin 11 is then unseated from the mated position as
follows. As
inward force PP2 is applied, pin 11 moves up ramped surface 49 and along
surface 41 (so
that it is no longer captured between surfaces 50 and 46) and it slides along
surface 51.
Once pin 11 is freed, connector 1 can then be withdrawn from adapter 2.
Because flipper
29 can rotate about axis X, the biasing force FL is overcome and flipper 29
rotates
clockwise as viewed in Figs. 7e and 7f.
Many modifications and variations of the present invention are possible in
light of the
above teachings. It is therefore to be understood that within the scope of the
appended
claims, the invention may be practiced otherwise than as specifically
described. Various
11
CA 02594549 2007-07-11
WO 2006/076061 PCT/US2005/038013
modifications, changes and variations may be made in the arrangement,
operation and details
of construction of the invention disclosed herein without departing from the
spirit and scope
of the invention. The present disclosure is intended to exemplify and not
limit the invention.
12
