Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
WO90/154~ ~ PCT/US90/03267
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TERO~G~ cOAxIAL CAB~E cONNEc~OR
Notice of Related Applicatio~
This patent application is a continuation in part of
U.S. Patent Application Serial No. 07/434,068 filed onNovember 3, 1989, which is a continuation in part of U.S.
Patent Application Serial No. 07l364,917, filed on June 9,
1989.
Field of the Invention
The present invention relates to connectors for
coaxial cables. More particularly, the present invention
relates to a very low cost, easily installable feedthrough
connector for coaxial cable of the type typically u~ed
indoors for wideband RF signal distribution, for example.
Backaround of the lnvention
Coaxial cable is in widespread use for distributing
wideband radio frequency ("RF") information, such as
television and radio signals~ Coaxial cable typically
provides two conductors, a central axial conductor and an
outer conductor which is substantially concentric with the
inner central conductor. The central conductor is
typically completely surrounded by the outer conductor, and
a low-loss, high dielectric insulation material, such as
plastic foa~, separates the two-conductors. An outer
insulating jacket is usually, although not necessarily,
provided over the outer conductor to provide electrical
insulation and physical protection to the cable.~ The outer
conductor may be a single element, or it may be a composite
of several layered elements of conductive foil, wire braid,
etc. One element of a composi~e outer conductor
construction may be a conductive film or coating applied to
the outside surface of the -low-loss, high dielectric
35 - insulation :material.~
Relatively large diameter, semi-rigid coaxial cables
- are widely used outdoors in cable telèvision distribution
WO 90/15454 ~ r~ ~ ~ $~ q~ ~ ?C~i'lJS~ 26/
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ne,worXs as a delivery conduii for delivering the cable
network signals to drop box locations near the service
subscriber's premises. Smaller, more flexible coaxial
cables having external insulating jackets are used to
provide service drops to the subscriber premises.
connectors are provided for connecting the cables in
the outdoor environment. Such..connectors not only must
provide positive, signal-tight electrical connections, they
must also provide positive leak-tight, sealed physical
connections to prevent intrusion of moisture into the
cabie. Installation of such connectors typically requires
cable end preparation such as coring or removal of the
insulator dielectric core for some distance, followed by
installation and tightening of the conductor assembly by a
trained craftsperson, with or without special tools,
depending upon the conductor/cable design. Typically, the
; outdoor environment connectors provide a central connector
element which is secured in coaxial arrangement over an
exposed end portion of the central conductor. The central
connector element thus contributes significantly to the
securement of the connector structure to the prepared cable
end.
Usually, the distribution network operator does not
: want a subscriber to.install a connector to.a.cable for use
with "outside plant" distribution boxes,-cables and the
like; ;..thus, special keyed tools are often provided for use
by trained ..installers in order to preclude:.unauthorized
.. . .
access to system distribution boxes, service drops and the
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: 30 Within the subscriber.premises the opposite situation
.... ~ ., .. ~ .
~often ~.exists. .. Usually, .the subscriber~has a-number of
appliances which .require interconnection and connection to
.. ~
the .service cable outlet ~ack, ;typically-mounted to and
: : ~ ext nding ~outwardly-from a~.wall~plate within~the home or
other interior location, etc.~Connections may be needed
betw en~the.service jack and-~the jacks of.a television set,
.a video..cassette . .recorder^:("VCR"),. and a stereo FM
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receiver, ror example.
Small diameter (approximately one quarter inch or
smaller), flexible coaxial cables are typically employed to
accomplish the needed connections. These coaxial cables
typically include a solid wire central conductor, a foam
core, an outer composite conductor formed of an inner
aluminum coating on the foam core, one or more layers of
open-mesh aluminum wire braid and one or more layers of an
aluminum foil. The outer composite conductor is typically
covered by a plastic outer insulator jacket of one or
several layers of insulating material in order to complete
the coaxial cable construction. The dimensions of such
coaxial cables may vary, depending upon type and source
thereof. Also, the properties of the cable may vary,
depending on type and source, and aIso depending upon such
factors as ambient temperature. When ambient temperature
is low, the polymer cable materials become very stiff and
difficult to manouver during connector installation
procedures. Also, the foil coated inner insulating core
may vary in diameter from about .140 inch to as much as
about .200 inch.
These small diameter cables have been made available
to .the- consumer in standard lengths with connectors
,installed at- the factory. Also, connectors have been made
. 25 available for - installation, but installation of these
connectors to a prepared cable end has typically required
a~crlmping tool~ for crimping a retaining 'ferrule, or a
tool~for spreading a~retaining slip ring, or the tighening
: : of~:.a compression nut which retains the connector to the
: 30~ cable end, or the like. Some connectors for indoor service
provide and reguire compressive:'coaction betwèen the face
..of~the~-.thread-d jack and -'the connector body, which is
achieved in~practice by -tightening a threaded nut of the
..connector...oYer~the oUter threads'-'of the jack. l
:35~ The::-connectors ~for~~indoor ~servicë'~aré` known as
"feedthrough".;.connectors,~in -the~'sense that ~there is no
sseparate ~centra~ connector element- of; the' connector
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provided for connec~ion, the center conductor of the cable
providing this element of the connection mechanism. The
center conductor is usually engaged by a receptacle element
of a jack. such element, sometimes referred to as a center
seizure mechanism, when present, provides a positive
mechanical engagement between the connector assembly and
the center conductor of the coaxial cable.
In the case of the feedthrough connector, an exposed
end portion of the solid wire central conductor of the
lo~ coaxial cable is directly engaged by the center seizure
mechanism of the jack when the feedthrough connector is
mounted thereon. Since the central conductor of the
coaxial cable is not maintained in mechanical engagement
with the feedthrough connectors, and since those connectors
function only to feed or connect the outer conductor to the
jack and thereby to position the exposed central conductor
for engagement with the central gripping mechanism of the
jack, the prior techniques.for securing the connector to
the cable have proven to have drawbacks related to
installation and have proven not to be entirely
satisfactory for ready installation and extended, reliable
use within indoor use environments.
Irrespective of the particular approach followed by
the prior art, hitherto there has not been a very low cost
: 25 feedthrough coaxial cable connector which may be easily
:as:sembled and attached to the cable with a simple
manipulation by ;a user without special tools,~ or skills,
and which provides a positive, superior engagement over
. time..with the jack to which it is mated for use.
: ~ 30 . . .~A wide.variety~of techniques are to be found in the
.. ,. coaxial~cable~.~connector. art for attaching a feedthrough
. connector .to;.a prepared cable end. .one..representative
example~.~ is to be found in the Quackenbush U.S. Patent No.
3,781,762. Therein, a tubular connector body includes an
;.35 annular..flare. ~....The body is dimensioned to fit between the
insu}ating Icor-.and .outer conductor of the prepared cable
end, and it aligns and positions an exposed end section of
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wogo/ls4s4 ~ ?~ f~ 1 PCTtUS90/03267
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the central conductor. The annular flare of the tu~ular
body causes the outer conductor to become stretched over it
as the body is pushed between the core and the outer
conductor during installation. A cylindrical ferrule, such
as a split ring or crimp ring, - is then installed over the
body inside of the annular flare. ~he Quackenbush
arrangement is said to provide 'good electrical and
mechanical connection of the cable outer conductor to the
connector body. However, the Quackenbush connector cannot
be easily installed on the prepared cable end without
special tools needed for installation of the clamping
ferrule.
As mentioned, another feedthrough connector relies
upon a compression engagement obtained by tightening a
threaded nut to the jack. The tightened nut of the
connector compresses the outer conductor against the .-
connector body and thereby secures the connector to the
cable. One drawback of this approach is that when the nut
is not tightened upon the threaded jack, or when the
,) connector end is not engaged with the jack, a slight tug or
jerk on the connector may cause it undesirably to become
separated from the cable.
Other more conventional approaches are to be found in
. ,the coaxial-cable connector art which include means for
engaging the exposed end of the central conductor. For
example, British Patent Specification 621,459 describes a
tubular connector body for insertion between the insulation
; cor ~and the outer conductor of a coaxial cable. An annular
,flared or bulged region expands the outer conductor of the
,, ,"30,~,cable, and a longitudinally extending split ferrule tube is
, ,~,pushed~over the coaxial cable end to surround the body at
,the ilbulged region :80 as to' press the cable against the
~bulged region ~to improve electrical connection and
~mechanical- ~ttachment.~, The ferrule includes fingers
3~5~enàbling~it to be~ secured to the connector body after it is
positioned in place.~
, ; , An annular split`ring is described in the Leeper U.S.
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Patent No. 2,805,399 in order to retain an outer conductor
of a coaxial cable along a narrow ring location immediately
adjacent a bulged annular ~rustoconical clip portion of a
body which is slipped under the outer conductor of the
coaxial cable in order to provide very secure mechanical
retention o~ the cable to the connector. Hexe, a special
tool is needed in order to position and install the slip
ring.
In the Pugner U.S. Patent No. 4,053,200, a connector
body has two radially raised portions. A plural-fingered,
elongated brass ferrule slides over the cable and the outer
radially raised portion in order to seat or nest between the
two raised portions of the body and press the outer
conductor of the cable against the connector body. While
the elongated brass ferrule provides a radial band of
circumferential compression force to press the cable outer
conductor against the tubular body, similar to the manner
described in the Quackenbush reference discussed above, no
engagement is provided between the elongated ferrule or
other structure of the connector and the cable behind the
outer raised portion of the connector body. Apparently, to
aid requisite securement of the cable to the connector, the
Pugner reference teaches a central connector structure
which is crimped or otherwise secured to an exposed end
2~ section of the central conductor of the cable.
Without the further retention means by the central
connector structure as shown in the Pugner patent, tugging
and pulling ~tresses upon the coaxial cable will tend to
cause it to become -disconnected fxo~ the connector as
described by Pugner, especially iP the connector is
threaded onto the jack -at the ti~e.- Also, any flexures of
the cable, particularly within an indoor environment such
as the home,~wili tend to cause the outer conductor to
stretch and-possibly to lose.n effective electrical contact
with the ridge-of~thejouter raised ~ portion'and/or-~provide
an unwanted signal leakage path at-the connector.
The Schwartz U.S. Pa~ent No. 3,264,602 provides a
W090~15454 ~; ~ ?,` `. t PCT/US90/03267
. . .
connector body for a coaxial cable which has a rearwardly
tapered, ringed frustoconical surface which is slipped under
the outer conductor of the coaxial cable. An outer member
snap-locks over the cable in a manner which compresses the
outer conductor against the frustoconical surface in order
to lock the cable to the connector and to provide a
positive electrical connection bétween the inner surface of
the outside conductor of the cable and the facing
frustoconical ringed surface of the conductive connector
body.
The Lee U.S. Patent No. 4,789,355 provides a coaxial
cable connector plug which has tines or leaves which slide
over the threaded end of the jack. An outer annular sleeve
may then be pushed forward over the tines in order to
compress them against the threaded jack and lock the
connector plug against the jack in the manner of a
compression collet, even though the plug is not threaded
to mate with the threads of the jack.
The Samichisen U.S. Patent No. 4,834,675 describes
what the inventor calls a "snap-n-seal" coaxial cable
connector for a prepared end of a coaxial cable. This
four-part connector assembly includes a mandrel body 30
which has a ramped contour 39 diverging from the rear end
thereof, so that the body 30 may be press fit between the
dielectric core and the shielding braid. As seen in Fig.
2B and as best seen in ~Fig. 4, the ramped contour 39
appears to flatten out and ends at a step inwardly forming
a right angle with the flattened region. A plastic
compression,~ sleeve 60 is-pushed over the body 30 and the
cable end. The, compression sleeve snap-locks into a metal
collar member 20 and is said thereby to lock the cable end
to the connector assembly., Since the ramped contour 39
-~ appears to end at a -flattened region, the body 30 fails to
provide a knife edge for effectively cutting into the braid
~or aluminum ~sheet , forming- the-~outer conductor of the
,coaYial:~cable. ~ ,s"~
,The Ito et~al. U.S.,Patent No. 4,249,790 describes a
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push-on type connector plug for a coaxial cable end. In
pertinent part, the connector plug includes a slot~ed shield
casing forming a plurality of resilient ~ingerY which engage
the outer cylindrical surface of a connector receptacle as
the connector plug is pushed onto the receptacle. The
fingers appear to be contoured to cooperate with an outer
band structure in order to provide a spring bias force
which pushes the fingers against the outer cylindrical
surface of the receptacle and thereby provide a good
electrical and ~echanical push-on, pull-of~ attachment.
The Morello Jr. U.S. Patent No. 3,1~6,382 describes a
crimp type coaxial cable connector 12 which includes a
mandrel body having an integrally threaded mating cap for
mating with a receptor connector 14. The Morello Jr.
connector device is not a push-on feedthrough connector.
While the foregoing approaches recognize the problem
of providlng effective contact and positive mechanical
attachment of the prepared cable end and the cable
connector, none of the foregoing approaches achieve a
simplified, easily installed, positively acting feedthrough
coaxial cable connector intended primarily for ready
installation by the untrained user or consumer or by the
trained technician, and for reliable use typically within
an indoor environment over an extended time period.
2~
- - Summary of the Invention with Obiects
A general object of the present invention is to
provide a feedthrou~h coaxial cable connector which
overcomes -the limitations and drawbacks of the prior art.
; 30A more specific object of the present invention is to
provide a feedthrough coaxial cable connector for indoor use
which may be installed by a user with exertion of but
moderate finger strength and without any special tools or
....
- - skills being required. ~
-35---one more specific object of the present invention is
to provi~e a feedthrough coaxial cable connector which
~achieves improved -flexual strain relief against rearward
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WO90/15454 ~ PCT/US90/032~7
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pulling force thereby to prevent the cable from being
disconnected from the connector in response to tugging or
pulling forces whether or not the connector is pulled free
of the jack. That is to say, a specific object of the
present invention is to provide a feedthrough coaxial cable
connector which preferentially releases from a jack with
which it is mated, rather than becoming damaged and
inoperative by separation of the connector and the coaxial
.- cable end.
10Yet another specific object of the present invention
is to provide a kit of a few co-acting parts which may be
assembled and installed by the consumer as a connector on an
easily prepared end of an indoor coaxial cable by hand
without special tools and without special training or
skills.
Still a further specific object of the present
invention is to provide a retenton ring having a resiliently
deformable portion of elastomeric material which coacts
with an annular or helical blade edge forming an annular or
helical barb of a mandrel body underlying the outer
conductor, so that once locked in place, the resiliently
deformable portion of the retention ring effectively locks
the:cable onto the.connector and impedes rearward tugging
forces from causing the cable end to be detached from the
connector. ... - -`
~ Yet one more specific object of the present invention
: :is~.to provide a mandrel body for a coaxial cable connector
which has: an annular- or helical blade edge formins a
sharplyicontoured.~surface projecting outwardly from a
: 30 substantially tubular mandrel body portion, and to use an
~elastomeric retention ring to cause an aluminum-foil and
braded:~wire -portion of an outer conductor of the coaxial
.r~.--cable to-be .~....contacted by the blade edge in a way which
fosters positive.: long term-connection to the foil and
;35 ~braded wire .conductor elements-without formation of
insulating oxides:and without~--actually shearing the fine
wires of-the outer conductor braid, so that the connector
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will operate reliably throughout wide ranging temperature
cycles of the ambient surroundings and without impairment
resulting from occasional movement and tugs on the cable.
Still one more object of the present invention is to
provide, most preferably by die casting., a mandrel body
including a tubular portion defining an annular or helical
blade edge forming a sharply contoured surface projecting
outwardly from the tubular portion.'The tubular portion may
be formed to act as a collet in order to engage differently
dimensioned coaxial cables .within a predetermined
dimensional range. In this object ramping is effectively
promoted with the aid of an expendable conically shaped
guide for providing a ramp between the different cable
diameters.
Yet one more object of the present invention is. to
provide a nesting tool for containing a kit of parts .-
comprising the elements of the cable connector in a manner
which facilitates proper and ready assembly of the elements .
into an installed feedthrough connector at the prepared end
of a coaxial cable.
A feedthrough coaxial cable connector is provided for
connecting to a prepared end of a coaxial cable' having an
exposed solid-wire central.conductor. In accordance with the
principles of the present invention, the connector includes
a tubular mandrel body of conductive'''material such as
yellow. brass which has.been plated with a suitable metal
or alloy, such as tin,~.in order to improve lubricity, for
examplo. The tubular mandrel body is -dimensioned to be
.
prQs~ed. between a foil-bonded dielectric core and other
:~ 30 .elements of an outer conductor .~of the prepared'end of the
cable.:. ... . . .~,~ .- t,,3 .,. " , . . ...
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. In one presently preferred~embodiment, the mandrel
body preferably_includes a.:rearwardly converging, generally
frustoconical surface:portion defining a shallow'angle with
respect to the cable,~a first-radial wall portion defining
:; a~ knife edge -with~the.frustoconical surface :portion, a
tubular...shank portion.extending from the'first radial wall
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woso/~s454 ~ PCT/US90/03267
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portion to a second radial wall portion, and a jack
engagement portion coaxial about the exposed central
conductor and dimensioned to fit on and contact an outer
surface of a jack with which the connector mates in use.
The jack engagement portion is preferably adapted to
diverge radially from the second radial wall portion
thereby enabling an initial slide-on engagement with the
outer surface of the jack. A tight friction fit is
desireably achieved between the jack engagement portion and
the outer surface of the jack. In one preferred form, the
jack engagement portion defines an inside compression
collet structure. Preferably, the mandrel body is formed
by die casting, in preference to machining.
In another aspect the mandrel body preferably
includes a helical barbed threàd extending radially
outwardly therefrom in the nature of a shallow, spaced' ~
apart continuous thread of controlled sharpness to enable
the mandrel body to be rotatably inserted onto the prepared
cable end by threading into the underside of the outer
conductor, thereby to establish a positive electrical
connection, as well as a positive mechanical connection, but
without actually shearing the fine wires typically forming
at least a part of the outer conductor.
A 'radial ' compression 'providing structure, which
preferably may include a 'flanged or splined snap-ring,
includes a resiliently deformablé elasomeric'portion which
is shaped and dimensioned to cause an inside surface region
. .
of the outer conductor to bear directly against and bend
over the knife edge barb formed'by the first radial wall
portion at~the inside end of the'frustoconical portion of
the mandrel body. ' ^ ~ ' ' ''
;Prèferably,- a -slideable 'shell is disposed over at
least the jack engagement portion of'the mandrel body. The
shell ~is-slideably~ positionable~ ~generaily away from a
' 35 connector`end fac$ng the ~outer~sùrfacè of the jack to ënable
the~jack"`'engagemè'nt portion of t ~ con'néctor'to slide over
the ~outer ~surface ' oi 'the ~ack,''and is slideably
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WO90/1545~ ~ PCT/US90/03267
posi~ionable toward the connector end so as to radially
compress the radially diverging jack engagement portion
against the outer surface of the jack to enable the the
connector to be securely connected thereto in a positive
5 friction fit. -
In one aspect of the present invention, the slideable
shell further defines a radial portion for compressing a
region of the coaxial cable outer conductor against the
frustoconical surface portion of the mandrel body when the
slideable shell is slideably positioned toward the
connector end.
In another aspect of the present invention, the jack
engagement portion is slotted longitudinally to form a slip
ring for slideable engagement over the outer surface of the
jac~.
In a further aspect of the present invention, the
jack engagement portion includes plural slots, and it
functions as a compression collet to lock onto the outer
surface of the plug as the slideable shell is positioned
toward the connector end facing the jack.
In one more aspect of the present invention, the snap
ring includes a cap portion for fitting snugly over the jack
engagement portion of the mandrel body thereby to provide
initial additional strength to resist hoop stresses that may
develop in the ~ack engagement portion before the slideable
_shell means is positioned toward the connector end facing
the jack.
In still a further aspect of the present invention,
..
the slideable shell is adapted to guide the snap ring into
position over the coaxial cable end and adjacently against
^ ^ thê first radial wall region of mandrel body during
installation of the connector onto the prepared end of the
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coaxial cable.
In a somewhat different aspect of the present
inven~ion a method is provided for assembling a feedthrough
coaxial cable connector from a ~it of parts at an end of a
coaxial cable, the method comprising the steps of:
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wosn/l54s4 ~ PCT/US90/03267
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preparing an end of the cable by peeling back a first
cylindrical portion of outer insulator covering for a first
length to expose an outer conductor braidjfoil layer, and
peeling back the outer conductor braid/fcil layer and
coaxially underlying dielectric insulator f or a second
length shorter than the first length thereby to expose a
- center solid conductor wire end portion,
providing a kit of parts by the steps of preforming a
tubular mandrel body of conductive material dimensioned to
be pressed between a dielectric core and an outer conductor
:~ Of the prepared end of the cable, the mandrel body as
preformed including an annular or helical knife edge
surface extending from a tubular shank portion, a radial
wall portion extending radially outwardly from the tubular
shan~ portion, and a coaxial jack engagement portion
extending forwardly from the radial wall portion and
coaxially disposed about the exposed central conductor and
dimensioned to slide onto and contact an outer surface of a
jack with.which the assembled connector mates in a close
fitting friction engagement, and preforming a radial
compression member for compressing the inside surfac.~ of the
outer conductor of the coaxial cable over the knife edge of
the tubular mandrel body installation,
sliding' the 'radial compression member over the
:; 25~prepared~ cable end in one direction of movement away from
the ~prepared:end,'
installing':~the mandrel body~onto the prepared end of
the:~ciaible by pushing it onto the cable end in the case of
:the -iannular knife:~'blade or rotating it onto the cable end
. .. :~ 30 -.in.the~ case:^'of-the helical knife blade, and
sliding:~the- radial compression member over the
prepar-d end of the cable installed on the mandrel body so
..as~ to compress the inside surface o~ the outer conductor of
~ th~ coaYial cablè"'over the knife edge of'the tubular
::: `.. .-35~: mandre~1';body~
The radial-~compression member may be preformed as a
:'' retention or~snap-ring, and the kit of parts may further
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advantageously include an outer shell which cooperates with
and co-acts with the snap-ring to position it during
assembly and installation and further to compress the jack
engagement portion against the jack when the assembled
connector is in use in its intended manner. A "throw-away"
installation tool which enables the kit of parts to be
nested for delivery to the user and which facilitates ready
and easy assembly and installation of the connector onto a
prepared end of the coaxial cable is yet another aspect and
advantage of the present invention. The tool may also
provide a visual gage for installation, and it may also be
adapted to self-release, once the connector elements are
properly installed on the prepared cable end.
These and other objects, aspects, advantages and
features will be more fully understood and appreciated upon
consideration of the following detailed descripion of
preferred embodiments, presented in conjunction with the
accompanying drawing.
Brief ~escription of the Drawin~s
In the Drawings:
Fig. 1 is a greatly enlarged partial view in
elevation and longitudinal section along a,central axis of
a portion of a coaxial cable connector incorporating
principles of the present invention.
Fig. 2A is a greatly enlarged diagrammatic view in
elevation and longitudinal section of a portion of a
resiliently elastomeric snap ring element of the Fig. 1
connector., Fig. 28 is an end view in~elevation of the
30 ~inside, collet structure of the mandrel body of~the Fig. 1
connector. , Pig. 2C is a view in elevation and partial
section of the mandrel body of the Fig. 1 connector
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modified to define an inside helical thread within the
collet ætructuré portion thereof. Fig.-2D is an end view
in ~elevation of the inside collet structure in which the
fingers thereof,are formed by,~,parallèl saws. Fig. 2E is a
view ~in elevation and partial - section of the Fig. 2D
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~O90/t~54 ~ PCT/US90/03267
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mandrel body. Fig. 2F is a view in front elevation of an
outer shell of the Fig. 1 connector. Fig. 2G is a view in
partial section and side elevation of the Fig. 2F outer
shell.
Fig. 3 is a longitudinally exploded view of the Fig.
1 connector about to be installed on a prepared cable end of
a coaxial cable with the aid of one form of expendable
plastic assembly tool or jig.
Fig. 4 shows the Fig. 3 assembly nested within the
assembly jig incident to installation of the Fig.
connector onto the coaxial cable end.
Fig. 5 shows the Fig. 4 assembly with the coaxial
cable installed thereon.
Fig. 6 shows the installed connector assembly with
the outer shell element slid back to a position enabling the
connector to be installed on a receptacle or jack. -
Fig. 7 shows the installed connector assembly mounted
on a receptacle or jack with the outer shell pushed forward
to lock the connector in place on the receptacle.
Fig. 8A illustrates in front view and axial section a
tined, resiliently elastomeric portion of a snap-ring in
accordance with the principles of the present invention.
Fig. 8B illustrates the Fig. 8A tined snap-ring in rear
elevation. - ~
Fig. 9 shows in exploded view an alternative
embodiment of connector in accordance with the principles of
he present invention.
Fig. lO shows the Fig. 9 mandrel element positioned
onto the prepared cable end.
Fig. 11 shows the co~pleted assembly of the Fig. 9
embodiment. - -
i Fig. 12 shows the Fig. 9 embodiment engaging a
connection receptacle. - ~ ~
- ~; Fig.-'13 illustrates-yet another embodiment of the
present invention in unassembled,:`axially exploded view.
Fig. 14 shows the Fig.~13`connector mandrel mounted on
a prepared end of a coaxiàl cable;
:
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',- '~ ' " ' , . ' .
'~'
w~ nn~ L~ PCI/US90/03267
i o
Fig. 15 shows completion of assembly of the Fig. 13
connector on the prepared end of the coaxial cable in
accordance with the present invention.
Fig. 16 shows the Fig. 13 connector in engagement
with a connection receptacle.
Fig. 17 shows yet a further embodiment of the present
invention inn unassembled, axially exploded view.
Fig. 18 shows the Fig. 17 mandrel mounted on a
prepared end of a coaxial cable.
Fig. 19 shows completed assembly of the Fig. 17
mandrel on a prepared cable end and as mounted upon a mating
connection receptacle.
Pig. 20 shows another embodiment of the present
invention in unassembled, axially exploded view.
Fig. 21 shows partial assembly of the Fig. 20 mandrel
being mounted on a prepared end of a coaxial cable.
Fig. 22 shows placement of a resiliently elastomeric
band over the Fig. 20 mandrel.
Fig. 23 shows the now fully assembled Fig. 20
embodiment engaging a connection receptacle.
Fig. 24 shows yet another embodiment of the present
invention in unassembled, axially exploded view.
Fig. 25 shows placement of the Fig. 24 mandrel onto
the prepared end of a coaxial cable.
Fig. 26 shows placement of a snap member over the
mandrel-cable assembly depicted in Fig. 25.
Fig. 27 shows the fully assembled Fig. 24 embodiment
in electrical and mechanical attachment with a eonnection
~ . .. .
receptacle or jack.
Fig. 28 illustrates yet another embodiment of a
. . .
connector assembly in accordance with the present invention
in unassembled, axially exploded view in elevation and
partial section.
; Fig. 29 shows the Fig. 28 embodiment nested in
initial, unassembled arrangement incident to installation
upon a prepared coaxial cable end. An expendable insertion
tool provides a nest or container for holding and aligning
.
.
W O 90/15454 ~ ~ /US90/03267
the uninstalled component parts of the Fig. 28 connector
assembly in axial alignment to facilitate assembly onto the
prepared end of the coaxial cable.
Fig. 30 illustrates installation by rotation of the
Fig. 28 container and nested connector assembly elements
onto the prepared coaxial cable cable end.
Fig. 31 illustrates the Fig. 28 connector assembly
after the installation procedure of Fig. 30 has been
completed.
Fig. 32 illustrates the assembled Fig. 28 connector
assembly in electrical and mechanical connection with a
receptacle or jack.
Fig. 33 shows yet another embodiment of connector
assembly in accordance with the principles of the present
invention. Fig. 33 is an exploded view of the connector
assembly in elevation and partial section along a
longitudinal explosion axis.
Fig. 34 illustrates the mounting of the mandrel
portion of the Fig. 33 connector assembly onto the prepared
cable end.
Fig. 35 illustrates the Fig. 33 connector assembly
following placement of a resiliently elastomeric band over
the Fig. 33 mandrel.
Fig. 36 illustrates the Fig. 33 connector assembly in
electrical and mechanical attachment with a receptacle or
jack.
Fig. 37 comprises a cable end view in elevation of an
embodiment of a colleting mandrel body which is radially
. .
expansive thereby to adapt and be used with coaxial cables
. . 30 having insulating cores of varying diameters within a
predetermined range in accordance with principles of the
present invention. -
~ Fig. 38 is a side view.in elevation and section ofthe Fig. ;37 mandrel body,;taken along the line 38 in Fig.
~35 37.-
~
.. . . . . .. .. . . .
Fig. 39 is a somewhat diagrammatic view in sideelevation of the Fig. 38 mandrel body and an expendable
.
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wn ~n/l~s~ 4~ t~ PCTtUS9OtO3267
. .
. - - 1~
.. . . ...... ... . . .
conical, ramp-shaped colleting guide member enabling
installation of the Fig. 38 mandrel body onto two cables
having inner cores of differing diameters.
Fig. 40 is a view in partial section and axial
explosion of the Fig. 28 coaxial cable connector embodiment
showing a modified container/nesting tool.
Fig. 41 illustrates placement of the coaxial cable
connector elements within the container tool and threading
of the assembly and tool over the prepared end of the
coaxial cable.
Fig. 42 illustrates initial engagement of the
dielectric core of the cable with' the plug end of the
container tool.
Fig. 43 illustrates the final position of the Fig. 40
assembly when the dielectric core of the cable has pushed
the container tool to a point of disengagement between the'
teeth thereof and the slots of the mandrel cap.
Detailed Descri~tion of Preerred Embodiments
With reference to Fig. 1 a coaxial cable 10 includes
a central longitudinal conductor 12 which is concentrically
surrounded by a high dielectric, insulator material 14, such
as plastic foam for example. A thin'metal conductive foil
or coating 16, typically ~formed 'of aluminum alloy, is
bonded to the outer surface of and thereby 'contains the
foam core 14 and embedded central conductor 12. An open
mesh wire braid or wrap 18 is wrapped or placed immediately
outside of the outer metal'coating 16 to pro~ide mechanical
strength to the cable and yet, to permit the ca~le 10 to
' 30 flex-guite freely without damagé.-~- Additional layers of
aluminum foil and wire braid may-be''included as part of a
composite outer conductor. Together,- these composite
elements 16,_18 sform -an-outer electrical conductor and
. shield which;is su~stantially concentric with,'' and spaced
35 (ffl the dielectric core material 14) away from the center
conductor l2.-~:c~ - !' ,~a
An outer ~-~insulator -coating - 20 of 'a suitable
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WO9l~/154~,~ 5? ri ~ O ~ P~T/U ,90/03267
thermoplastic resin material~covers the outer electrical
conductor to seal the cable from the am~ient, to isolate the
outer conductor electrically from the ambient and to provide
some additional stiffness and mechanical protection to the
cable 10.
The cable 10 may be type RG-6 having a nominal
overall diameter of about .275 inch, or a type RG-59 having
a nominal overall diameter o~ about .240 inch. The
diameter vf the inner core material 14 of ~he RG-6 cable is
about .185 inch, whereas the diameter of the inner core
material 14 of the RG-5g cable is about .145 inch, thereby
il}ustrating a core diameter variance range of about .040
inch between two very popular indoor cables.
As shown in Fig. 1, the end of the cable lo has been
prepared by cutting back the outer conductor 20, outer braid
18, outer foil jacket 16 and dielectric core 14 for a short .-
distance tc, a location referred to by the lead line
associated wi~h the reference numeral 22 in Fig. 1, so as
to expose a short segment of~ the central conductor 12. The
zO exposed segment of the central conductor 12 is engaged by
a central conductor receptacle within a conventional jack
typically having a threaded outer cylindrical surface. The
jack may be a standard threaded 'IF" port connector having
.. . .
a nominal outer diameter of about .375 inches although this
.
diameter is known to vary somewhat in practice.
As shown in Figs. 1 and 2A through 2G,-a preferred
emkodiment 24 of a connector incorporating the principles of
the present invention includes a mandrel body 26 formed of
a suitable conductive material, such as yellow brass, for
, . . . . .
example.~ Preferably, the mandrel body 26 is die cast with
a two-part mold * at separates along the longitudinal axis
of the mandrel body 26. ~s formed by die casting, for
.. . .. .
example, the mandrel body 26 is formed with suitable reliefs
... . . .... .
and edge contour,s, so that it cooperates as intended with
35 ~the ,other structural elements of the connector without
, ., ,. . ~ , .~ . .
~ ~ , scratching or unwanted interferences. By employing a die
... . . . . .. . . .
casting operation, rather than machining,-eac mandrel body
wn~n~ a . ..~ PCT/US9OtO3267
'. ' s,':.?
. .
26 may be formed in less than one second, leading to
substantial economies in manufacturing. Preferably, the
mandrel-body 26 is plated with a suitable metal or alloy,
such as tin, in order to improve its lubricity
characteristics.
The conductive mandrel body'26 includes a thinned
tubular region 28 with a slight, axially converging chamfer
29 at the end of the body 26. A frustoconical region 30
forms a frustoconical outer surface region 31. Preferably,
the frustoconical outer surface region 31 forms an acute
angle (less than 90 degrees) with a central longiudinal
axis of the mandrel body 24 (which is generally in
alignment with the central conductor 12 of the coaxial
cable 10). Preferably, the angle formed by the surface
region 31 with the longitudinal axis is between about 20
degrees and about S degrees, and it is preferably 10
degrees, plus or minus one degree.
: ' A first, radially extending annular wall 32 extends
outwardly to Converge the inner end of the frustoconical
surface 31'thereby to form an annular.knife-edge projection
or barb 33. m e barb edge 33 is designed to be a cutting
: surface which cuts or bites slightly into an inside ring
portion of.the outer metal braid and foil layers 18 without
~: ~actually shearing them, thereby to cut through any oxide or
~::25 other:~ insulating formations or' deposits on the inside
surface-of the metal foil 16 so as to achieve and maintain
a ~positive, very~ low resistance e:lectrical connection
between:~the mandrel body 26 and the outer conductor foil
- and braid 18. As 8een in~ Fig. ' 1, the frustoconical
30 surface ~31 forms an aCUte angle with the annular wall 32,
-most pr-ferably about 30~degrees. '~
A~:thinned tubular region~34 extends away from the
ase of.~the first.radial wall portion 32 and meets a
..thicken-d:. s-cond;radial wall portion~-36.~ Thé second wall
portion 36. extends radially outwardly to the location of a
colIet ~structure~37 at which~'fingers or leaves^~38 extend.
..- The~ringers :38 define the''inside 'collet structure 37 and
,-~: ::
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- -wo9n/l54s4 ~ PCT/US90/03267
.. .. . . .. ..
provide an inside cylindrical engagement surface suitable
for engaging the outer threaded surface of a jack with
which the connector 10 is intended for use, such as an "F"
jack, for example. The inside surface of the collet
structure 37 may be smooth,--as shown in Fig. 1, or it may
be provided with a shallow-cut helical groove or thread 39
as shown in Fig. 2C. A radially diverging chamfer or
bevel edge 40 at the entrance of the collet structure of
fingers 38 facilitates slidable engagement of the leaves or
fingers 38 upon the threaded surface of the jack. The
pitch of the groove 39 is set to correspond with the thread
pitch of the jack. If the groove 39 is present, a more
positive attachment is achieved with the threaded jack than
if the thread 39 is not provided, should such a
characteristic be desired.
Preferably, each finger 38 is formed with a thickened .-
region 42 adjacent to the chamfer 40 and becomes gradually
thinned at a region 44 adjacent to the second, thickened
radial wall portion 36. The inside geometry of the
connector 24 is generally cylindrical when in an
unstressed, uncompressed state. In this relaxed state
which enables the conductor 24 to be slid over the outer
surface of the jack, the outer surfaces of the'fingers 38
define a slightly curvéd or ~frustoconical geometry.
.. 29 Preferably, there are four fingers 38 provided by the
-mandrel body 26. There may be more' or fewer fingers;
howover, four fingers-38, each defining a quadrant of a
cylinder and separated by longitudinal slots 46 from
adjacent fingers, cooperate to'provide'a very effective : '
30. compression collet closurè '"structure for~' positive
... ..engaqement over the outer~surface of the jack,^when a hoop,
:~.band, slip ring, f' or other circumferentially compressing
member is slidably'positioned~ over the'thickéned~regions 42
. of the fingers ~38.^'" Thé fingers' 3 38 may'be formed by
35 :cross-sawing across the collet`' structure 37 at right
.. ~ angles, as shown in Fig. 2B, for example.? ' Altérnatively,
, . . . . . . . ` . . . . .
; and preferably for mass production,~ the fingers 38 are
-~, ~, '~ , - , : ' . . '
,:
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.
,
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wQ4n!l ~C~ PCT/US90/03267
formed by a single machining operation of two parallel saws
which move in one direction across the collet structure 37,
as shown in Figs. 2D and 2E.
The connector 24 further includes a resiliently
5 deformable elastomeric cap 50--which is preferably formed by
injection molding of a suitable thermoplastic resin
material. The cap 50 includes a deformable flange region
52 which becomes thinned and tapered into a rearwardly
flaired, knife-like annular edge 54. When the cap 50 is
properly positioned over the mandrel body 26 and cable 10,
a cap region,56 snugly fits over the fingers 38 and
provides some additional hoop strength and protection to
the fingers 38 from overbending due to proper insertion
into the jack. '
As shown in Fig. 2A, the cap 50 is dimensioned such
that the flange region 52 snap-locks into a recess formed
adjacent to'the first radial wall 32 of the mandrel body 26.
since thè flange region 52 is initially flaired outwardly,
the thinned annular edge 54 curls, up around the outer
plastic insulation 20 and tends to stretch or pull it down
over the knife edge 33 of the mandrel body 26. When
positioned against the outer insulator 20 of the cable 10,
the flaired edge 54 of the cap 50 actually presses the
cable 10 against the first radial wall portion 32, causing
thé outer conductor braid and foil layers 18 to become
sharply creased at the knife edge 33. This resultant
.
crease not only prevents aluminum oxide from impeding a
.. .
very low resistance, high conductance contact between the
outer conductor and the conductive mandrel body 26, it also
effectively,;prevents rearward displacement of the cable 10
relative to the conductor 24. In effect, tugging forces
applied to,the cable lO,will cause the connector to become
disconnected.from the iack, rather than resul~ in separation
,of the,,,cable end from the conductor, given the acute angle
, 35 of ~the,~,iknife edge 33 of the mandrel body 26 and the
, compressive action -of ;the flaired edge 54 of the
,~ elastomeric cap 50. ,-
:
WO 90/15454 ;~ r ~ PCI'/US90/03267
.. . . .. ....
2~
Preferably, an outer shell 58 is provided whichfurther cooperates with and strengthens the connector 24.
The shell is formed by injection molding of a hard plastic
ma~erial, such as 6/6 nylon. As diagrammed in Fig. 1, the
S shell 58 has a forward cylindrical portion 60 which is
dimensioned to compress the mandrel fingers 38 against the
outer surface of the jack when the portion 60 is slid
forward along an axial locus denoted by the arrow 61. An
inside edge region 62 of the portion 60 bears against the
cap region 56 which in turn presses inwardly against and
compresses the fingers 38 toward the outer surface of the
jack in the manner of a compression collet.
At the same time, a rear, frustoconical portion 64 of
the shell 58 positions an inside surface 66 against a region
of the outer plastic insulator 20 adjacent to .the
frustoconical surface 31 of the mandrel body 26. The'
inside surface 66 thereby clamps the insulator and outer
conductor jacket against the surface 31, thereby preventing
relative movement of the cable 10 relative to the connector
24 and particularly relative to the knife edge 33, and
further accentuating the creasing action of the outer
conductor ~jacket over the mandrel knife . edge 33 and
preventing rearward movement relative to the connector 24.
The outer shell 58 must have a sufficiently high
29 modulus of eiasticity and resilience to stretching so that
' :' it - effectively 'closes' the fingers 38 of the collet
- st~ ture 37 as- thë~ shell 58 slides forward over the
- mandrel body 26. Since ~F~ jacks are found in practice to
; ' range in diameter over about an .015~ range, the sizing of
`: '30 the:inside diameter of the edge ' region 62 should be such
`:'' that when the front~edge of the outer shell portion 60 is
: - ~'' slid about halfway ovèr the''collet structure 37, a secure
:-~ :. grip is thereby 'àchieved bètween the structure 37 and a
... . , ~ . .......... .... . . .
~' jack of nominal`diameter,' e.g. .375 inches. . In this
35~-manner,~ smaller and larger diameter jacks of the "F" type,
'for~exa~ple-,~; may bè securely engaged by the connèctor 24,
- 'particuiarly if thé inside 'surface of the collet structure
.
. .. - . ~ - . . . - . . . . , : . .. . . . .
. . - - ~ .. .
..
:. . ~ : .
. .. . .
wnsn/1~4s4~ ?~i3~ PCTtUS90/03267
. ~ . ^ . . .; , . .
37 ~ s r- ~vided w,th tha shal~ow ~hread 3g, as shown in Fig.
2C. A modulus of elasticity of at least 100,000 pounds per
- square inch, and a resiliency enabling stretching up to
about four percent of nominal are presently preferred
characteristics for the outer shell 58.
An oxide-formation preventing gel may be coated onto
~ the mandrel body 26 on the radial wall portion 32 adjacent
to the knife-edge 33, or on the frustoconical surface 31,
or at both locations as desired. The gel may have
lubricating properties and may facilitate insertion of the
mandrel body 26 between the dielectric core 14 and the
outer conductor foil jacket 16. Gels under compression,
such as.disclosed in commonly assigned U.S. Patents Nos.
4,634,207; 4,643,924; 4,721,832; and, 4,701,574, the
disclosures of which are hereby incorporated by reference,
are suitable for use with the embodiments of the present
invention disclosed herein.
Also, with the connector 24, a space 53 is provided
between the thickened radial portion 36 of the mandrel body
: 20 26 and the flaired region 52 of the deformable elastomeric
cap 58. This space 53 enables excess outer cable material
to be curled up and accomodated, further relaxing the
tolerance reguirements for preparation of the end of the
cable 10 for installation of the conductor 24.
Turning to Figs. 3-7, an assembly sequence of a kit
of parts which will eventually compr~ise the connector 24 is
illustrated. Therein,.a molded plastic assembly tool or jiq
70 is shown in axial alignment with the other components
previously discussed in conjunction with Figs. 1 and 2. In
30 Fig. 3, an end 11 of the cabie 10 is prepared as shown, so
: : that the foam core 14 and exposed outer.. coating 16 extend
: : : .a~small distance beyond the outer insulator 20, and braid
and a.luminum foil layers 18. The braid and foil layers 18
are folded up and ~ radially outwardly away from the
: 35 longitudinal axis of the cable lO. The cable end ll.may be
;~prepared with a special tool,~or.simply~by using a sharp
~knife or~single edgé razor blade; .The stubby wires of the
, ~
~: :
,
~: :
~ '' ' ' ' .
.
~ ' '' ' ' .
-WO90/15454 SA tS j~ 1 d PCT/US90/n3267
~raid and foii la~rs lR ~-2 f~ld2d back by the installer~s
finger after the ring of outer insulator coating has been
cut away.
In Fig. 4, the ma~drel body 26, cap 50 and outer
shell 58 are nested into the assembly tool 70 in preparation
for receiving the prepared cable end 11 as shown therein.
A annular ring portion 71 of the tool 70 provides a
convenient grip location for,the user's fingers. The cable
is gripped in one hand, and the assembly tool 70 containing
the body 26, cap 50 and outer shell 58 is gripped in the
other hand. Then, the cable is pushed toward the tool 70
and into and through the the outer shell and cap 50. When
the cable engages the mandrel body 26, it pushes the body
forward and away from the cap 50 and outer shell 58, as
shown in Fig. 5.
In Fig. 5, the cable end 11 is shown inserted into
the tool 70.and the end has pushed the mandrel body 26 to
the forward end of the tool 70, passing over and leaving
behind the cap 50 and the shell 58. If the tool 70 is
formed of a transparent plastic material, then it is
possible for the installer to see that the cable end 11
has passed over the frustoconical region 30 and the thinned
tubular region 34 and is butted up against the outside of
the second radial wall portion 36. In this manner the
transparent tool 70 acts as .a gage for aiding proper
installation. ,jWhen the cable..has reached ,the desired
~position, as shown ,in Fig. 5, the-cable 10 is then pulled
away from the tool 70, with the installer grasping the
outer shell 58. .,
As the ,cable 10 and mandrel body 26 are drawn
:rearwa.rdly, the outer shell 58 retains the cap 50 and causes
~ it to slip over the cable 10 and over.the annular bulge
.~ therein now formed by the outer jacket,elements lying upon
, ~ , the surface 31. Continuing to pull the cable 10 relative
.' 35 to the shell 58 ,causes the .cap 50 to.be mo~ed into its
'~ , final locking position .over.. ,the thinned tubular region 34
in front of the fir t~wall ~portion 33,.,,as shown in Fig. 1.
, :
::
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- .: - . .
',
. ~ ~
wn~n/ls4~4 ~ o~ PCTIUS90/03267
_ l7 `~ ~J `, `;
,, , _ , , . . , _ . _ , _ , _
The cap 50 is thus snap-locked against the outer insulator
20 at the vicinity of the radial wall 32 and prevents
rearward movement of the cable 10 by coaction with the
knife edge barb 33 of the mandrel body 26.
It will be appreciated that the tool or jig 70 forms
a convenient pac~age for containing a kit of parts including
the mandrel body 26, snap-lock cap 50-and outer shell 58.
A "blister-pack" package may include the tool and parts and
be formed onto a cardboard substrate for convenient
distribution to the householder or other installer/user of
the connector 24. The' substrate may conveniently provide
printed instructions and illustrations for assembly and use
of the connector 24.
In Fig. 6, the connector assembly 24 has been
withdrawn from the tool 70 (which may now be discarded as
spent, or retained for installation of another connector'
assembly 24~. Then, with the outer shell in the slid back
position as shown in Fig. 6, the connector 24 may be pushed
onto a jack 72, as shown in Fig. 7. The exemplary jack 72,
typically an "F" jack, may define an outer threaded surface
74 against whiCh-the fingers 38 of the mandrel body 26 come
into contact. The shallow 'thread 39 (if present on the
' inside surface of the collet structure 37) is pitched to
~'mate with the ' threaded surface of the jack. The outer
-~ 25 shell 58 is' then slid forward to a position shown in Fig.
7 which simultaneously locks the fingers 38 against the
' threaded surface 74 and the outer jacket elements against
the frustoconical surface 31 of the mandrel body 26. The
; conn-ctor 24 is now securely, yet removably, attached to
'~- -30 the~connector. Any'tugging on the cable 10 will result in
the ;c'onnec~or 24' becoming dislodged from the jack 72 in
pre~ere:noe'-'to an unwanted separation of the connector 24
''and'the prepàred cable'end 11. - '
- To remove thë connector 24 from'the'jack 72, the
'35~ outer~sh-11 58 may be grasped between'the fingers and
''"rotated~ 'to:facilitate~loostening the connector from the
''jack.'': The ~shèll 58 is then slid rearwardly, thereby
~: .
.
.:
,
WO90/15454 ~ J~ PCT/US~0/03267
releasing the fingers 38 and enabling ready removal of the
connector assembly 24. An outer annular ring or a pair of
opposed flanges 59 (Figs. 2F and 2G) formed on the shell 58
provides a suitable thumb-finger gripping mechanism to
enable rotatable and slideable-movement of the shell 58
relative to the mandrel 26, cap 50 and cable 10 for
installation and removal of the connector 24 to and from
the jack 72.
Fig. 8 shows a cap soa which is provided with a
lo plurality of splines 55 in lieu of the continuous resilient
portion 54. The operation of the cap 50a is similar with
that described for the cap 50. However, the splines 55 dig
into the outer plastic insulation 20 of the cable 10 to
create a series of stress points or barbs which coact
securely to retain and lock the braid and foil layers 18
against the knife- edge barb 33. In practice, the pointed
tips of the splines 55 actually dig into the outer plastic
coating 20.
Figs. 9-12 illustrate an alternative embodiment 24a
of a connector embodying the principles of the present
invention. In these figures, the same reference numerals
are applied to the elements discussed in conjunction with
Figs. 1- 7. A modified cap 50b includes a thickened radial
~ portion 52a leading to the deformable annular edge 54. A
disk 58a provides the finger olosure function provided by
the region 60 of the shell 58, previously described. The
advanta~e of this embodiment 24a is that it provides a very
flat and compact connector assembly. Also, there is very
little drawback from stress relaxation of the thick disk,
a problem sometimes encountered with the thinner outer
shell 58 of the earlier described embodiments. One
disadvantage with the connector 24a is that without the
:-~ portion 64 of the outer shell, there is no additional
reinforcement or support provided to the cable end at the
vicinity of the ;frustoconical portion 30 of the mandrel
. . . ,, . , ~ , ,
- - body 26. ~-
: - ~ Figs. 13-16 illustrate yet another embodiment 24~ of
. , :
w~sn/ls4~4 PCT/US90/03267
........ , .; . .. ~ -;
... . . . . ... . . ..
,, _
cor.nec~er embo~y~ng the p inciplPs o. the present invention.
In this embodiment 24b, the outer shel} 58 has been
replaced by a split ring 58b which is nested in a suitable
band retention structure 39 formed around the periphery of
the fingers 38 of the mandrel shell 26a. The cap is formed
as a disk 50c which includes the elastomeric edge 54. An
outer portion of the disk SOc enables the fingers to grasp
the connector 24b for installation and removal from the
jack 72. Because of the thickness of the disk 50c, there
is very little stress relaxation, and once installed on the
cable end over the mandrel body, the disk 50c will securely
lock the cable end to the mandrel body 26. This embodiment
24b also has the drawback of not providing any structure
for retaining the cable at the frustoconical portion of the
mandrel body as is provided by the outer shell 58. Also,
the split-ring 58b does not provide as secure an engagement
with the jack as is achieved with the inside compression
collet structure 37.
Figs. 17-19 illustrate a connector 24c also embodying
the principles of the present invention. In this
embodiment, only two elements are present, a slightly
modified mandrel body 26b, and an elongated elastomeric
threaded cap 50c. The fingers 38 o~ the mandrel body 26b
are thickened for greater hoop strength. The threaded cap
25 50c is fit over;the cable 10. The cable end 11 is then
; installed on the mandrel body 26b, and the cap 50c is then
threaded onto the mandrel-cable arrangement as shown in
Fig. 19, thereby securing the cable end 11 to the mandrel
body 26b.
~ Figs. 20-23 illustrate yet another embodiment 24d
embodying~the~principles of the présént invention. In this
three-part ~embodiment 24d, the cap 50 is replaced by a
cylinder~50d of elastomeric material. The cylinder 50d and
an outer shell 58b are positioned onto the cable 10, and it
is then forced onto the mandrel body 26 as with the
connector 24. The she}l 58b is then used to push the
elastomeric cylinder 50d into a position overlying the
.
: ' : '
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WO 90/154~4 . . . P~/US90/03267
knife edge 33 of the mandrel body 26, as shown in Fig. 22.
Then, the connector 24d may be installed on the ~ack 72 and
the shell 58b slid forward to loc~~ the fingers 38 onto the
outer threaded surface 74 of the jack, as shown in Fig. 23.
The connector 24e shown in Figs. 24-27 reveals yet
another combination of cap 50e and outer shell 58c for use
with the originally described mandrel body 26. In this
embodiment of connector 24e, the cap 50e includes an
elongated tail section 53 which is dimensioned and
configured to overly the knife edge 33 of the mandrel body
26. When assembled and installed on the jack 72, the outer
shell 5B is pushed to its forward position by grasping the
outer f~ange 59. This action locks the fingers 38 onto the
threaded outer surface 74 of the jack 72. A tapered
annular edge 63 cooperates with the cap soe to provide
further compression to the cable jacket at the vicinity of
the knife e~ge 33, as shown in Fig. 27.
. The connector 24f, shown in Figs. 28-32, includes a
mandrel body 26c in which the frustoconical knife-blade edge
33 of the prior embodiments is replaced by a knife-blade
helical thread or edge 33a projecting radially outwardly
from the thinned tubular region 2~. In one practical
example, the thinned tubular region may be slightly
frustoconical and have an averagé outside diameter of about
.180 -inch. The helical knife blade edge 33a has an apex
which is approximately .2 io inch and is formed as an
acutely angled projection extènding from the tubular region
28. The heiical knife blade 33a is so shaped as to bite
sufficiently into the finè aluminum strands of the outer
conductor braid or aluminum foil to obtain a positive
- electrical-contact with the'foil and also to provide a
positive mechanical-securement therewith, without causing
the strands to shear or break off. ' ~'
An effective co~promlse between sharpness and dulln~ss
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of the knif~ edge is'"to make it flat across for about two to
three mils. A one mil ~lat ls too~sha~x`p and will result in
shearing'the fine wire'br'a'id, whilé'an eight mil radius at
w~nr1~c~ PCT/US90/03267
Lhe edge has ~ell fou~.d .o ~a too d~ll wi ~ rêsultant
slippage of the braid under tension. Ideally, the knife
blade 33a should subject the braid wires to shear stresses
without actually resulting in shearing them off. In
practice the compromise is reached by considering sharpness
of the knife edge 33a and the hardness of the material of
which it is made.
The jig or tool 70a is modified to include teeth 80
which are sized and positioned to engage the slots 82
defined between the fingers 38 of the collet structure 37.
An outer end portion 84 of the tool 70 may be provided with
radial spokes or projections to facilitate gripping and
impartation of rotational torque to the tool 70 to enable
insertion of the threading mandrel 26c onto the prepared
end of the cable 10. Rokational installation of the
mandrel 26c onto the prepared cable end is illustrated
diagrammatically in Fig. 30 by the arrow 84. The use of a
helical knife-blade edge 33a on the mandrel 26c has been
found to be particularly advantageous in order to
facilitate ready installation of the assembly 24f onto the
coaxial cable 10 at low ambient temperatures which cause
substantial stiffness of the outer elastomer jacket 20
thereof. When the outer jacket 20 has stiffened due to
lower ambient kemperatures, it aids in causing the helical
knife-blade edge 33a to bite into and positively engage the
outer conductor braid/foil of the coaxial cable 10.
Otherwise, the assembly of the connector assembly 24f is
the same as described hereinabove for the assemby 24.
The connector 24g, shown in Figs. 33-36, combines the
Fig. 28 helically threaded mandrel body 26c with the
elastomeric cylinder 50d used in the Fig. 20 connector
embodiment 24d. The mandrel 26c is threaded onto the
prepared cable end as explained above in connection with
the connector body 24f of Fig. ~8, whereas the elastomeric
cylinder 50d is positioned as explained in conjunction with
the Fig. 20 e~bodiment above.
The mandrel body 26d, illustrated in Figs. 37-39,
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WO 90/1545d ~ r ~ ~ .. ,: PCT/USgO/03267
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solves 2 prcblem oth~rwls2 asscciat~d with coaAla' cables
having different diameter foam cores within a predetermined
size range. For example, an RG-59 cable lOa may have a
diameter of about .145 inch for the core 16a, whereas an
RG-6 cable lOb may have a diameter of about .185 for its
core 16b. Both cables may be effectively terminated by a
connector assembly includinq the mandrel body 26d. The
body 26d, otherwise identical to the body 26, is formed to
define e.g. four longitudinal slots 86. The slots 86 are
very narrow, e.g. .010 inch, for example; and they extend
from the cable end to the wall 36. An inside diameter,
denoted by reference numeral 88, at the cable end
corresponds generally to the outside diameter of the
smallest cable core 16a within the size range to be
accomodated, while an inside diameter, denoted by
reference numeral 90, of the central bore of the t~bular
portion 34 of the mandrel body 26d is sized to accomodate
the outside diameter of the largest cable core 16b within
the predetermined size range. The frustoconical portion
30a of the mandrel body 26d is tapered toward the cable end
diameter 88 on both the inside and outside thereof.
An expendable ramping tool 92 is provided for use in
attaching the mandrel body 26d to the prepared cable end.
- -:'' The ramping'tool 92, when positioned axially over the
exposed central conductor 12 of the cable 10 to abut the
core 16 causes the fingers formed by the slots 86 to expand
'- ` radially as the mandrel body 26d is pushed toward the core
"'-16. This radial expansion of the cable end of the mandrel
body 26d positions it so that it will properly come into
overlying engagement with the cable core, whether it be of
a'~'smaller diameter such as the core 16a, or of a larger
' diameter such as the core 16b. After the outside of the
' -core 16'is engaged, the ramping tool'is forced axially all
the'~way through the tubular portion and into the region
enclosed by the collet structure 37 where it may be'''readily
' rèmoved and discarded by the installer.' -'''
' ' 'While 'the '"frustoconical knife-blade edge 33 is
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~ PCTIUS90/03267
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illustr2te~ in th.e ~ig. 37-39 embodlment, lt ls c1oar that
a helical knife blade edge 33a may also be used with
equally successful results in this embodiment.
Referring now to Figs. 40-43, the connector 24f
depicted in Figs. 28-32 and discussed in conjunction with
those figures is again depicted. However, in Figs. 40-43,
a modified tool 70b illustrated in combinatiOn with the
elements of the connector 24f and the cable 10. The tool
70b has a significant advantage in that it automatically
prevents over-installation of the connector mandrel 26c onto
the prepared cable end.
In certain locations, low light levels make it most
difficult or even impossible to gage whether the connector
mandrel body 26c has been rotated onto the prepared cable
end sufficiently. The consequence in practice has been that
the mandrel body 26c has been threaded onto the cable end
, too far, with the result that the outer conductor braid and
shield has become bunched up, leading to poor electrical and
mechanical connection of the connector onto the cable end.
The tool 70b is configured to prevent the mandrel body 26c
from being rotated too far onto the prepared cable end.
~ ~ , In accordance with an aspect of the present invention,
- the tool 70 is formed with a hollow cylindrical plug region
, 83. The plug region 83 is concentric-~with the connector
e}ements and with the prepared cable end. The plug region
, 83 ,defines~ an inner wall 85 which butts up against the
~^ ,mandrel,body, as shown in Fig. 41. A central opening 87 is
, , defined through the inner wall 85. Since the center
", ccnductor wire 12 has a diameter which typically ranges
between 32 mils~and-40 mils, the central-^opening 87 is
, sized,to be about twice the largest wire diameter, or about
,8,~,0"mils in diameter. This diameter is selected for two
,very ,importantl,reasons:, first,,it,,is sufficiently smaller
,c than,the~diameter,tof,,the dielectric core 16 of the cable 10
35 ~so that-an~end wall~l7;~thereof~will come into contact with
- ~ the inner wall;-85 and thereafter dislodge the tool 70b.
Secondly, the small diameter opening 87 serves as a gage to
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WO90/lS4~ 4 ~ )J~ PCT/US90/03267
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~~ ~ê suic ~ha~ ~he o~Jlter conductor 12 wnich is e~posed at t.h~
prepared cable end is not bent. (If the exposed end of the
inner conductor 12 is bent, damage will likely ensue to the
center contact within a receptacle with which the assembed
conductor and cable end will be used).
As shown in Fig. 41 the cable 10 is just entering
engagement with the mandrel body 26c. As the tool 70b is
rotated, the teeth 80 thereof engage the slots 82 between
the leaves 38 of the outer cap portion 37 of the mandrel
body 26c and cause it to rotate with the rotation of the
tool 70b. Fig. 42 illustrates a position at which the
mandrel body 26c has been screwed onto the prepared end of
the cable 10 to a position at which the endwall 17 of the
dielectric has butted up against the inner wall 85 of the
lS tool.
As shown in Fig. 43, continued rotation of the tool
70b causes the mandrel body 26c to move rearwardly along the
prepared cable end, and results in the dielectric core 26
projecting slightly beyond the end of the inner wall of the
mandrel body. At this position, the inner wall 85 of the
tool 70b is pushed away from the mandrel, causing the teeth
80 of the tool to become disengaged with the slots 82
between the cap fingers 38. At the point shown in Fig. 43,
further rotation of the tool 70b does not cause any further
rotation of the mandrel body 26c and thereby preven~s it
from becoming installed too far along the prepared cable
end. Thus, with the tool 70b, the installer may rotate it
relative to the cable 10 until automatic disengagement
occurs, at which point the mandrel body 26c is properly
installed to a correct length along the prepared cable end.
Whlle the same concept may be employed with a push-on tool
and annular barb 33, discusced previously, it is
~; particularly advantageous to use the concept with the
~mandrel body 26a havlng the heIical thread barb 33a.
Statement of Industrial AD~licabilitY
;The present invention realizes a three-part
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w~qntl~4~ ~ PCT/US90/03267
. .
reeatnrougn conneclor assem~iy ror a coaxla_ cab1~ which maV
be readily installed upon a prepared end of a coaxial cable,
and which efficiently and effectively clamps onto the
prepared cable end to provide a secure electrical and
mechanical securement to the outer conductor. A locking
mechanism for locking the connector onto a jack or
receptacle, and an installation tool, provide important
aspects of the present invention.
While the instant invention has been described by
reference to what is presently considered to be the most
practical of embodiments and the best mode of practice
thereof, it is to be understood that the invention may
embody other widely varying forms without departing from
the spirit of the invention. For example, the outwardly
lS diverging shape of the inside compression collet 37 may be
curved as opposed to frustoconical thereby to enable
overstro~e to account for the range in diametral tolerances
of various ~acks within a type ~ith which the connector may
be used. Also, alternatively, the outwardly divergent
shape may be provided by the cap member 50. The presently
preferred embodiments are presented herein by way of
illustration only and should not be construed as limiting
the present invention, the scope of which is more
^.r~ particularly set forth in the following claims.
What is claimed is~
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