U.S. patent number 3,846,738 [Application Number 05/348,242] was granted by the patent office on 1974-11-05 for cable connector.
This patent grant is currently assigned to Lindsay Specialty Products Limited. Invention is credited to Zdenek Nepovim.
United States Patent |
3,846,738 |
Nepovim |
November 5, 1974 |
CABLE CONNECTOR
Abstract
A connector for attachment to the end of a coaxial cable having
a core electrode and a conductive sheath electrode which includes a
housing having an integral tubular skirt formed from four
rearwardly extending tongues collectively formed with a rearwardly
facing external cam surface. A tubular cap formed with a forwardly
facing internal cam surface for engagement with the external cam
surfaces of the skirt screws on to the housing so that interaction
of the cam surfaces causes the tongues to be flexed radially
inwardly into gripping engagement with the sheath electrode of a
cable disclosed within the connector for electrical contact
therewith. A radially inwardly compressible and electrically
conductive collet sleeve coaxially disposed within the housing is
adapted to receive the core electrode of the said cable and to be
radially inwardly compressed by an electrically insulating
compressible bushing disposed about the collet sleeve. The bushing
has diametrically opposed projections extending through the tubular
skirt defining rearwardly facing external cam surfaces for
engagement by a second forwardly facing internal cam surface formed
in the tubular cap such that radially inward movement is
concurrently transmitted to the bushing and collet sleeve for
simultaneous gripping of the core electrode and sheath electrode
without any torsional shearing action between the said
electrodes.
Inventors: |
Nepovim; Zdenek (Lindsay,
Ontario, CA) |
Assignee: |
Lindsay Specialty Products
Limited (Lindsay, Ontario, CA)
|
Family
ID: |
23367184 |
Appl.
No.: |
05/348,242 |
Filed: |
April 5, 1973 |
Current U.S.
Class: |
439/584 |
Current CPC
Class: |
H01R
9/05 (20130101) |
Current International
Class: |
H01R
9/05 (20060101); H01r 017/04 () |
Field of
Search: |
;339/6C,89C,9C,91P,94C,126J,177R,177E,273R ;174/75C,88C |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,242,731 |
|
Jun 1967 |
|
DT |
|
1,109,914 |
|
Apr 1968 |
|
GB |
|
Primary Examiner: Gilliam; Paul R.
Assistant Examiner: Staab; Lawrence J.
Claims
What we claim as new and desire to protect by Letters Patent of the
United States is:
1. A connector for securement to the end of a coaxial cable having
a sheath electrode and a core electrode which comprises: a hollow
housing having a rearwardly extending and peripherally
discontinuous electrically conductive tubular skirt for radially
inward compression into gripping engagement and electrical contact
with the sheath electrode of a coaxial cable extending forwardly
into said skirt, said tubular skirt being formed with an external
cam surface and at least one longitudinal slot; a radially inwardly
compressible and electrically conductive collet sleeve mounted
generally axially within said housing for receiving an exposed
forward end portion of the core electrode of the coaxial cable
inserted into said connector; a radially inwardly compressible and
electrically insulating bushing generally coaxially disposed around
said collet sleeve and having at least one projection extending
through said slot formed in said tubular skirt, said projection
defining an external cam surface; a hollow tubular cap having
associated therewith at least one internal cam surface for conjoint
axial movement with said cap and for engagement with said external
cam surface of said tubular skirt and said external cam surface of
said bushing projection when said cap is disposed coaxially around
said tubular skirt whereby on forward axial movement of said cap
relative to said housing, said cap is adapted to cause radially
inward compression of said tubular skirt into gripping engagement
and electrical contact with the sheath electrode of the coaxial
cable disposed within said tubular skirt and adapted to cause
radially inward compression of said bushing and said collet sleeve
to move said collet sleeve into gripping engagement and electrical
contact with the core electrode of the cable; said compression of
the collet sleeve occurring concurrently with the compression of
the tubular skirt for simultaneous gripping of the core electrode
and sheath electrode without any torsional shearing action between
the said electrodes; and co-operating means on said housing and on
said cap for retaining said cap in a desired axial position on said
housing.
2. A connector as claimed in claim 1, in which said tubular skirt
is longitudinally divided by at least one pair of diametrically
opposed slits and by a pair of diametrically opposed slots into a
plurality of peripherally spaced apart and rearwardly extending,
radially inwardly and resiliently compressible tongues having an
external cam surface formed collectively thereon, and said bushing
having a pair of diametrically opposed projections formed thereon,
said slots permitting said bushing projections to extend
therethrough for engagement by an internal cam surface formed in
the hollow tubular cap.
3. A connector as claimed in claim 2, in which said slits and said
slots are equispaced about the tubular skirt.
4. A connector as claimed in claim 1, in which said tubular skirt
is internally serrated for gripping engagement with the coaxial
cable sheath electrode disposed therewithin.
5. A connector as claimed in claim 2, in which said tongues are
internally serrated for gripping engagement with the coaxial cable
sheath electrode disposed therewithin.
6. A connector as claimed in claim 1, in which said cap has a pair
of axially spaced apart forwardly facing internal cam surfaces, one
of said cam surfaces adapted to engage the external cam surface of
the tubular skirt and the other of said cam surfaces adapted to
engage the external cam surface of the bushing projection.
7. A connector as claimed in claim 2, in which said cap internal
cam surface is a frusto-conical or spherical surface.
8. A connector as claimed in claim 6, in which said cap internal
cam surfaces are frusto-conical or spherical surfaces.
9. A connector as claimed in claim 2, in which said bushing
projections define rearwardly facing external cam surfaces.
10. A connector as claimed in claim 9, in which said tubular skirt
external cam surface is a rearwardly facing frusto-conical or
spherical surface.
11. A connector as claimed in claim 1, said tubular cap defining an
annular space at its rearward end about the cable sheath electrode
and a sealing ring disposed within said annular space for
compression to provide a seal between said cap and said cable.
Description
BACKGROUND OF THE INVENTION
The present invention relates to electrical connectors and more
particularly is directed to connectors intended for securement to
coaxial cables of the type used in CATV distribution systems.
U.S. Pat. No. 3,668,612 issued June 6, 1972 discloses a connector
for a coaxial cable in which the abutment of metal component parts
on each other to transmit radial compression necessitates the
application of considerable torque for securement of component
parts together. It is a principal object of the present invention
to provide a coaxial cable connector in which a direct metal on
plastics abutment is attained to minimize and to reduce torque
requirements for securing the connector to a cable.
It is another important object of the present invention to provide
electrical connectors particularly suitable for use in a CATV
system which provides a satisfactory seal against the ingress of
moisture and dirt into the connector while providing effective
electrical connections and obviating any torsional shearing action
between the cable sheath and core electrodes.
And another important object of the present invention is to provide
a connector design which will minimize critical tolerance
requirements and thus enhance ease and economics of
manufacture.
These and other objects of the invention and the manner in which
they can be attained will become apparent as the description
proceeds.
SUMMARY OF THE INVENTION
In general, the present invention provides a connector for
securement to the end of a coaxial cable having a core electrode
and a conductive sheath electrode which comprises a housing having
a rearwardly extending skirt with slots formed in the skirt to
permit the projection beyond the plane of the skirt of cam surfaces
of a bushing disposed within the skirt, whereby a co-operating cam
surface formed internally in a cap can directly radially compress
the bushing.
In more detail, the connector of the present invention comprises a
hollow housing having integral therewith a rearwardly extending and
peripherally discontinuous electrically conductive tubular skirt
for radially inward compression into gripping engagement and
electrical contact with the sheath electrode of a coaxial cable
extending forwardly into said skirt, said tubular skirt being
formed with a rearwardly facing external cam surface and a pair of
diametrically opposed longitudinally disposed slots; a hollow
tubular cap having associated therewith a forwardly facing internal
cam surface for conjoint axial movement with said cap and for
engagement with said rearwardly facing external cam surface of said
tubular skirt when said cover sleeve is disposed coaxially around
said tubular skirt and adapted to cause radially inward compression
of said tubular skirt into gripping engagement and electrical
contact with the sheath electrode of the coaxial cable disposed
within said tubular skirt upon forward axial movement of said cap
relative to said housing; co-operating means on said housing and on
said cover sleeve for retaining said cover sleeve in a desired
axial position on said housing; a radially inwardly compressible
and electrically conductive collet sleeve mounted generally axially
within said housing for receiving an exposed forward end portion of
the core electrode of the coaxial cable inserted into said
connector; and a radially inwardly compressible and electrically
insulating bushing generally coaxially disposed around said collet
sleeve having diametrically opposed projections extending through
said slots formed in said tubular skirt, said projections defining
rearwardly facing external cam surfaces whereby, on forward axial
movement of said cap relative to said housing, said bushing and
said collet are radially inwardly compressed to move said collet
sleeve into gripping engagement and electrical contact with the
core electrode of the cable concurrently with the compression of
the tubular skirt for simultaneous gripping of the core electrode
and sheath electrode without any torsional shearing action between
the said electrodes.
BRIEF DESCRIPTION OF THE DRAWING
Other features and advantages of the invention will become apparent
from the following detailed description of the drawing, in
which:
FIG. 1 is an exploded perspective view, partly cut away, of a cable
connector of the present invention;
FIG. 2 is a longitudinal section of the cable connector shown in
FIG. 1 illustrating a coaxial cable loosely inserted therein;
FIG. 3 is a longitudinal section of the connector shown in FIGS. 1
and 2 illustrating the connector in the closed operative position;
and
FIG. 4 is a longitudinal sectional view of another embodiment of
connector of the present invention shown preparatory to securement
of the coaxial cable inserted therein.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference first to FIGS. 1 through 3, there is shown a
connector, designated generally by numeral 10, comprising a hollow
housing 12 and a cap 11 consisting of two components 14, 16 for
receiving and electrically securing a coaxial cable 18 having a
sheath electrode 20 and forwardly projection exposed core electrode
21. Housing 12 comprises a main body portion 13 with an hexagonal
external configuration and a cylindrical internal cavity 24 for
receiving collet 22 axially secured therein by frictionally fitted
annular spacer 26. Spacer 26, formed of a rigid electrically
insulating material, is secured within cavity 24 by circular
shoulder 25 crimped in the forward end of housing 12. Wire 27 of
collet 22 extends through a central opening 29 formed axially in
spacer 26 and shoulder 31 of collet 22 abuts inner face 33 of said
spacer. Collet 22 has a pair of diametrically opposed slits 35
longitudinally formed therein to permit compression of the end of
the collet as shown in FIG. 3.
Housing 12 has a forward threaded portion 28 for securement to a
box or the like enclosure, not shown, and a resiliently
compressible sealing ring such as an 0-ring 30, as shown more
clearly in FIGS. 2 and 3, seated in peripheral recess 31 for
providing a water-tight fit with said box. An external thread 32 is
formed rearwardly of central portion 13 for receiving mating
threads 34 of cap portion 14, a resiliently compressible sealing
ring 36 being positioned in peripheral recess 38 for providing a
seal between housing 12 and tubular sleeve 14 of cap 11.
A tubular skirt 40 is formed on housing 12 by rearwardly extending
peripherally discontinuous tongues 42 having a pair of slits 43 and
a pair of diametrically opposed slots 44 longitudinally formed
therein. Slits 43 permit inward compression of skirt 40 and slots
44 are adapted to receive projections 46 of bushing 48 centrally
disposed therein. Bushing 48, positioned coaxial with collet 22, is
formed of an electrically insulating material. The exposed external
cam surfaces 50 of bushing 48 are shown rearwardly biased to
receive forwardly extending cam surface 52, defined on the inner
wall of tubular sleeve 14, to permit radially inward compression of
the bushing and collet 22 for reasons which will become apparent as
the description proceeds. It will be understood that cam surfaces
50 can be formed by rounded or like projections extending through
slots 44 for engagement and inward compression by forwardly
extending cam surface 52 which, for example, can be frusto-conical
or spherical in cross-section. Also, tubular skirt 40 can have a
single longitudinal slot 44 formed therein to receive a single
bushing projection 46 for inward compression by sleeve cam surface
52.
The rearmost external surfaces of the tongues 42 of tubular skirt
40 are rearwardly biased to collectively form an external cam
surface 43, such as a frusto-conical surface shown, which is
adapted to engage forwardly facing bevelled internal cam surface 54
formed on the inner wall of tubular sleeve 14 for radially inward
compression of said tubular skirt tongues whereby serrations 56
formed on the inner surfaces of the tongues 42 of skirt 40 will
abut and positively engage the external surface of sheath electrode
18 for gripping engagement and electrical contact therewith.
Cap portion 16, having an hexagonal peripheral surface for
engagement by a wrench or the like tool, contains a threaded inner
surface 60 to engage threaded male surface 62 of sleeve 14 at the
rearward end thereof such that cap portion 16 can be screwed onto
sleeve 14 for compression of resiliently compressible sealing ring
64 therebetween and for rotation of sleeve 14 to screw cap 11 onto
housing 12.
With reference to FIG. 3, it will be evident that the screwing of
cap 11 onto housing 12 will axially advance the cap onto said
housing to compress ring 36, radially inwardly compress the tongues
42 of tubular skirt 40 onto sheath electrode 18, by mutual
engagement of internal sleeve cam surface 54 with tongue cam
surface 43, and to substantially simultaneously radially inwardly
compress bushing 48, by mutual engagement of internal sleeve cam
surface 54 on bushing cam surfaces 50, such that collet sleeve 22
will be compressed onto core electrode 21.
In use, the outer conductive sheath 20 and insulation 23 of coaxial
cable 18 are cut back to expose core electrode 21 and the cable end
loosely inserted into the connector, as shown in FIG. 2, such that
core electrode 21 is positioned within collet 22 and sheath
electrode positioned within tubular sleeve 40 to abut the rear face
of bushing 50. The cap 11 is screwed tightly onto housing 12 by
rotation of cap portion 16, and with reference now to FIG. 3, it
will be seen that skirt tongues 42 and collet 22 will be inwardly
compressed to grip and make electrical contact with the sheath
electrode and core electrode respectively, in the manner described
above, without relative rotational movement or shear between the
two electrodes.
FIG. 4 illustrates another embodiment of the present invention,
prior to locking in its operative sealed position, wherein a
unitary cap 80 is threaded onto housing 12 whereby axial forward
movement of the cap relative to housing 12 by the screwing of cap
80 thereon will radially inwardly compress the tongues of tubular
skirt 40 and bushing projections 46 to positively electrically
engage the cable sheath and core electrodes while compressing
sealing 0-ring 82 against housing 12 and compressing resiliently
compressible sealing ring 84 against skirt 40 and sheath 18
respectively to provide a watertight connection between the cable
sheath electrode and connector interior.
The structure of the present invention provides a number of
important advantages. Bushing 48 can be formed from a plastics
material such as nylon and the connector housing and cap formed of
a metal such as aluminum to provide little frictional resistance
therebetween as compared to conventional cable connectors which
utilize metal-on-metal bearing components. For example, components
of conventional cable connectors are fabricated from aluminum
because of aluminum's corrosion resistance and low cost. However,
aluminum on aluminum provides a poor bearing surface with high
friction therebetween and, by the use of aluminum on nylon, the
torque required to turn the connector cap onto the housing,
normally requiring in the order of 16 foot-pounds, is reduced to
about 3 foot-pounds. The direct abutment of caps 11 or 80 on
bushing 48 further minimizes critical tolerance requirements of the
connector with substantial savings in manufacturing costs.
* * * * *