U.S. patent number 3,671,926 [Application Number 05/060,410] was granted by the patent office on 1972-06-20 for coaxial cable connector.
This patent grant is currently assigned to Lindsay Specialty Products Limited. Invention is credited to Zdenek Nepovim, Lindsay.
United States Patent |
3,671,926 |
|
June 20, 1972 |
COAXIAL CABLE CONNECTOR
Abstract
A connector for attachment to the end of a coaxial cable having
an axial core electrode and an outer conductive sheath electrode
includes a sheath-gripping ferrule and a collet sleeve for gripping
an exposed forward end portion of the core electrode. The ferrule
and the collet sleeve are disposed within a tubular housing and a
plug bolt is threaded into the rearward end of the connector for
tightening both the ferrule and the collet sleeve radially inwardly
against the electrodes. Forward axial movement of the plug bolt is
converted to forward and radially inward movement of the
sheath-gripping ferrule through a first pair of co-acting
frusto-conical cam surfaces and the resulting movement of the
ferrule is operative through at least one second pair of
frusto-conical cam surfaces to cause radially inward compression of
the collet sleeve onto the exposed forward end portion of the core
electrode.
Inventors: |
Zdenek Nepovim, Lindsay
(Ontario, CA) |
Assignee: |
Lindsay Specialty Products
Limited (Lindsay, Ontario)
|
Family
ID: |
22029284 |
Appl.
No.: |
05/060,410 |
Filed: |
August 3, 1970 |
Current U.S.
Class: |
439/584 |
Current CPC
Class: |
H01R
9/05 (20130101) |
Current International
Class: |
H01R
9/05 (20060101); H01r 017/04 (); H01r 007/06 () |
Field of
Search: |
;339/177R,177E,273 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
1242731 |
|
Jun 1, 1967 |
|
DE |
|
828886 |
|
Dec 1, 1969 |
|
CA |
|
Primary Examiner: Marvin A. Champion
Assistant Examiner: Lawrence J. Staab
Attorney, Agent or Firm: Arne I. Fors Frank I. Piper
Claims
What I claim as new and desire to protect by Letters Patent of the
United
1. A connector for securement to a coaxial cable having a core
electrode and an outer conductive sheath and which connector
comprises a housing, a radially inwardly compressible and
electrically conductive ferrule disposed within said housing for
both forward movement therein and radially inward compression of
the rearward end of the ferrule into gripping engagement and
electrical contact with the outer conductive sheath of a coaxial
cable inserted into said connector, means movably mounted on said
housing for causing said forward movement and said radially inward
compression of said electrically conductive ferrule, and a radially
inwardly compressible and electrically conductive collet sleeve
mounted generally axially within said housing and electrically
insulated from said electrically conductive ferrule, for receiving
an exposed forward end portion of the core electrode of the coaxial
cable inserted into said connector and having associated therewith
a rearwardly facing external cam surface for contiguous surface
abutment with a forwardly facing internal cam surface integral with
the forward end of said electrically conductive ferrule whereby, on
forward movement and radially inward compression of said
electrically conductive ferrule into gripping engagement and
electrical contact with the outer conductive sheath of the coaxial
cable, resulting forward movement of said forwardly facing internal
cam surface associated with the said forward end of said
electrically conductive ferrule is operative, by virtue of its
abutment with said rearwardly facing external cam surface
associated with said collet sleeve, to cause outward abutment of
the said forward end of the ferrule against the housing to prevent
rotation of the ferrule and to provide radially inward compression
of said collet sleeve into said gripping engagement and electrical
contact with the core electrode of the
2. A connector as claimed in claim 1 which additionally comprises
an axially compressible and radially expansible sealing member
disposed within said housing around the outer conductive sheath of
the coaxial cable inserted into said connector plug and in which
said means for causing said forward movement and said radially
inward compression of said electrically conductive ferrule is also
adapted conjointly to cause axial compression and radial expansion
of said sealing member into sealing engagement with the outer
conductive sheath of the cable and with said
3. A connector as claimed in claim 1 which comprises a radially
compressible and electrically insulating bushing coaxially disposed
around said collet sleeve within said housing and having said
rearwardly facing external cam surface provided thereon and in
which said forwardly facing internal cam surface is provided on a
forward end of said electrically
4. A connector for securement to a coaxial cable having a core
electrode and an outer conductive sheath and which connector
comprises: a tubular body; a tubular plug bolt threadedly secured
to said tubular body at a rearward end thereof for axial threaded
movement relative thereto in a forward direction for securing a
coaxial cable within said connector; a radially inwardly
compressible and electrically conductive collet sleeve mounted
generally axially within said body for receiving an exposed forward
end portion of the core electrode of the coaxial cable inserted
into said connector and adapted to be compressed radially inwardly
into gripping engagement and electrical contact with such forward
end portion of the core electrode of the cable; a radially inwardly
compressible bushing coaxially disposed within said tubular body
about said collet sleeve and having a rearwardly facing external
cam surface; a stop means formed within said tubular body forwardly
of said radially inwardly compressible bushing and adapted to be
abutted thereby to restrict forward axial movement of said radially
inwardly compressible bushing within said tubular body; a radially
compressible and electrically conductive ferrule disposed within
said tubular body for axial forward movement therewithin with the
cable disposed axially therewithin, adapted for radially inward
compression into gripping engagement and electrical contact with
the outer conductive sheath of such a cable, and having integrally
formed therewith a rearwardly facing external cam surface and a
forwardly facing internal cam surface for contiguous surface
abutment with said rearwardly facing external cam surface of said
radially inwardly compressible bushing; and a forwardly facing
internal cam surface associated with said tubular plug bolt for
conjoint forward movement therewith in contiguous surface abutment
with said rearwardly facing external cam surface associated with
said electrically conductive ferrule, whereby, on forward axial
movement of said tubular plug bolt relative to said tubular body,
resulting forward movement of said forwardly facing internal cam
surface associated with said tubular plug bolt in contiguous
surface abutment with said rearwardly facing external cam surface
associated with said electrically conductive ferrule causes both
forward movement and radially inward compression of said ferrule
into gripping engagement and electrical contact with the outer
conductive sheath of the cable and whereby forward movement of said
forwardly facing internal cam surface associated with said
electrically conductive ferrule in contiguous surface abutment with
said rearwardly facing external cam surface of said radially
inwardly compressible bushing causes radially inward compression of
said bushing in turn radially inwardly to compress said collet
sleeve into gripping engagement and electrical contact with the
exposed forward
5. A connector as claimed in claim 4 which additionally comprises a
thrust ring disposed within said tubular body for forward axial
movement therewithin and having said forwardly facing internal cam
surface associated with said tubular plug bolt integrally formed
therewith as well as having a rearwardly facing and radially
extending surface for abutment with a forwardly facing and radially
extending surface of said tubular
6. A connector as claimed in claim 5 which additionally includes an
annular axially compressible and radially resiliently expansible
sealing member disposed between said tubular plug bolt and said
thrust ring and adapted radially to expand on forward axial
movement of said tubular plug bolt relative to said tubular body
thereby to provide a generally fluid-tight seal between said
tubular plug bolt and the outer conductive sheath of the
7. A connector as claimed in claim 5 in which said rearwardly
facing external cam surface of said radially inwardly compressible
bushing comprises a rearwardly facing and radially inwardly
tapering external frusto-conical surface, in which said forwardly
facing internal cam surface of said electrically conductive ferrule
is a forwardly facing and radially outwardly expanding internal
frustoconical surface adapted for contiguous surface abutment with
said frusto-conical surface of said radially inwardly compressible
bushing, in which said rearwardly facing external cam surface of
said electrically conductive ferrule is a rearwardly facing and
radially inwardly tapering external frusto-conical surface, and in
which said forwardly facing internal cam surface of said thrust
ring is a forwardly facing and radially outwardly expanding
internal frusto-conical surface adapted for contiguous surface
abutment with said external frusto-conical surface of said
electrically conductive
8. A connector as claimed in claim 7 in which said tubular plug
bolt is externally threaded for threaded engagement with a
corresponding internal thread formed within said tubular body in
proximity to said rearward end thereof and in which said thrust
ring is externally threaded for threaded engagement with said
internal thread formed within said tubular body during insertion of
said thrust ring into said tubular body and for sliding axial
movement within said tubular body forwardly of said internal thread
formed therein in abutment with both said forwardly facing surface
of said tubular plug bolt and said rearwardly facing and radially
inwardly tapering external frusto-conical surface of said
electrically conductive ferrule, whereby free non-rotational
rearward axial movement of said thrust ring out of said tubular
body when said tubular plug bolt is
9. A connector as claimed in claim 8 in which said electrically
conductive collet sleeve and said electrically conductive ferrule
are each formed with an internally disturbed surface for gripping
engagement with the exposed forward end portion of the core
electrode and with the conductive outer sheath respectively of the
coaxial cable disposed within said plug
10. A connector for securement to a coaxial cable having a core
electrode and an outer conductive sheath and which connector
comprises: a tubular body; a tubular plug bolt threadedly secured
to said tubular body at a rearward end thereof for axial threaded
movement relative thereto in a forward direction for securing a
coaxial cable within said connector; a radially inwardly
compressible and electrically conductive collet sleeve mounted
generally axially within said body for receiving an exposed forward
end portion of the core electrode of the coaxial cable inserted
into said connector and adapted to be compressed radially inwardly
into gripping engagement and electrically contact with such forward
end portion of the core electrode of the cable; a radially inwardly
compressible bushing coaxially disposed within said tubular body
about said collet sleeve and having a rearwardly facing external
cam surface; a stop means formed within said tubular body forwardly
of said radially inwardly compressible bushing and adapted to be
abutted thereby to restrict forward axial movement of said radially
inwardly compressible bushing within said tubular body; a radially
compressible and electrically conductive ferrule disposed within
said tubular body for axial forward movement therewithin with the
cable disposed axially therewithin, adapted for radially inward
compression into gripping engagement and electrical contact with
the outer conductive sheath of such a cable, and having integrally
formed therewith a rearwardly facing external cam surface and a
forwardly facing external cam surface; a thrust collar having
integrally formed therewith a forwardly facing internal cam surface
for contiguous surface abutment with said rearwardly facing
external cam surface of said radially inwardly compressible
bushing, which thrust collar also has integrally formed therewith a
rearwardly facing internal cam surface for contiguous surface
abutment with the forwardly facing external cam surface integrally
formed with said electrically conductive ferrule, a thrust ring
disposed within said tubular body for forward axial movement
therewithin and having a forwardly facing internal cam surface in
contiguous surface abutment with said rearwardly facing external
cam surface of said electrically conductive ferrule and a
rearwardly facing and radially extending surface for abutment with
a forwardly facing and radially extending surface of said tubular
plug bolt whereby, on forward axial movement of said tubular plug
bolt relative to said tubular body, resulting forward movement of
said forwardly facing internal cam surface of said thrust ring in
contiguous surface abutment with said rearwardly facing external
cam surface of said electrically conductive ferrule causes both
forward movement and radially inward compression of said ferrule
into gripping engagement and electrical contact with the outer
conductive sheath of the cable and whereby forward movement of said
forwardly facing external cam surface of said electrically
conductive ferrule in contiguous surface abutment with said
rearwardly facing internal cam surface of said thrust collar causes
both outward abutment of said thrust collar against the tubular
body to prevent rotation of the ferrule and forward movement of the
thrust collar forwardly facing internal cam surface in abutment
with the rearwardly facing external cam surface of the radially
inwardly compressible bushing to compress said collet sleeve
radially inwardly into gripping engagement and electrical contact
with the exposed forward end
11. A connector plug as claimed in claim 10 in which each said cam
surface is in the form of a generally frusto-conical cam surface.
Description
The present invention relates to electrical connectors and more
particularly relates to connectors intended for securement to
coaxial cables of the type used in CATV distribution systems.
Many different electrical connectors for the aforementioned purpose
are presently available but the practical requirements for an
effective re-usable connector of this type have proved to be
difficult to attain.
From a commercial point of view, to maintain costs as low as
possible, it is desirable that such a connector has the minimum
possible number of component parts consistent with effective
operation and that the manufacture and assembly of such a connector
should involve as few manufacturing steps as possible. Also, such a
connector must present electrical characteristics to match the
electrical characteristics of the coaxial cable to which it is
secured to avoid signal distortion.
It is a principal object of the present invention therefore to
provide an inexpensive electrical connector which is simple in
construction and which is simple to manufacture.
Another important requirement of such a connector is that it
provide a positive grip on both the core electrode and the outer
conductive sheath electrode of a coaxial cable since, in the
absence of such positive securement to both electrodes, the
different thermal expansion rates of the two electrodes can lead to
the core electrode being pulled loose from such a connector,
particularly when the electrodes are exposed to large temperature
variations.
Still another important requirement of an electrical connector
particularly intended for use in a CATV system is that such a
connector should incorporate an adequate seal against the ingress
of moisture and dirt into the connector and consequently ultimately
into the electrical insulation disposed between the core electrode
and the outer sheath of such a coaxial cable, without cracking or
damaging the cable shield component while permitting facile release
and re-use of the connector.
It is another important object of this invention therefore to
provide an electrical connector for positive fluid-tight securement
to the components of a coaxial cable which will permit release and
re-use of the connector and cable.
And another object of the invention is the provision of a connector
particularly suited for use in CATV distribution systems.
In its broadest scope, the present invention provides a connector
for securement to a coaxial cable having a core electrode and an
outer conductive sheath and which connector comprises a housing, a
radially inwardly compressible and electrically conductive ferrule
disposed within said housing for both forward movement therein and
radially inward compression into gripping engagement and electrical
contact with the outer conductive sheath of the coaxial cable
inserted into said connector, means movably mounted on said housing
for causing said forward movement and said radially inward
compression of said electrically conductive ferrule, and a radially
inwardly compressible and electrically conductive collet sleeve
mounted generally axially within said housing and electrically
insulated from said electrically conductive ferrule for receiving
an exposed forward end portion of the core electrode of the coaxial
cable inserted into said connector and having associated therewith
a rearwardly facing external cam surface for contiguous surface
abutment with a forwardly facing internal cam surface associated
with said electrically conductive ferrule whereby, on forward
movement and radially inward compression of said electrically
connective ferrule into gripping engagement and electrical contact
with the outer conductive sheath of the coaxial cable, resulting
forward movement of said forwardly facing internal cam surface
associated with said electrically conductive ferrule is operative,
by virtue of its abutment with said rearwardly facing external cam
surface associated with said collet sleeve, to cause radially
inward compression of said collet sleeve into said gripping
engagement and electrical contact with the core electrode of the
cable.
In accordance with a particularly useful feature of this invention,
the sheath-gripping ferrule of such a connector is usefully
integrally formed with a rearwardly facing external frusto-conical
cam surface and with a forwardly facing internal frusto-conical cam
surface. Such rearwardly facing external cam surface can then be
adapted to coact with a corresponding forwardly facing internal cam
surface of a thrust ring which can be moved forwardly relative to
and within the housing of the connector by a plug bolt threadedly
inserted into the rearward end of such a housing. The forwardly
facing internal cam surface of the ferrule of such a preferred
embodiment of a connector can similarly be arranged to coact with a
rearwardly facing external frusto-conical cam surface of a
resiliently and radially inwardly compressible and electrically
insulating bushing coaxially disposed about the radially inwardly
compressible and electrically conductive collet sleeve intended to
be compressed radially inwardly into gripping engagement and
electrical contact with the exposed forward end portion of the core
electrode of the cable.
Other objects, features and advantages of the invention shall
become apparent as the description herein proceeds.
The invention will now be described merely by way of illustration
with reference to the accompanying drawings, in which:
FIG. 1 is a longitudinal, axial sectional view, partly in
elevation, through one previously known connector, showing a
coaxial cable secured within the connector;
FIG. 2 is an exploded and fragmentary elevation of the prior art
connector shown in FIG. 1 with certain parts being omitted or shown
in section for the sake of clarity and for the purpose of
illustrating the manner of operation of that particular
connector;
FIG. 3 is a longitudinal, axial sectional view of another known
connector with a coaxial cable secured within the connector;
FIG. 4 is an exploded and fragmentary sectional view of the
connector shown in FIG. 3, partly in elevation, illustrating the
manner of operation of the connector;
FIG. 5 is a longitudinal, axial sectional view through an
embodiment of a connector in accordance with the present
invention;
FIG. 6 is an end elevation of a radially inwardly compressible and
electrically insulating bushing forming an important component of
the connector shown in FIG. 5 as viewed along line 6--6 of FIG. 5;
and
FIG. 7 is a longitudinal, axial sectional view through an
alternative embodiment of a connector in accordance with the
present invention also showing a coaxial cable secured within the
connector.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In order to facilitate understanding of the present invention and
of the advance in the art provided thereby, the two previously
known connectors shown in section in FIGS. 1 and 3 of the
accompanying drawings will first be described. The manner in which
these known connectors operate will also be described with
particular reference to FIGS. 2 and 4 respectively of the
drawings.
For convenience, the left-hand ends of all the connectors shown in
the accompanying drawings will be referred to herein as the forward
ends of those connectors, while the right-hand ends into which
coaxial cables can be inserted for securement of the connectors to
such cables will be referred to herein as the rearward ends.
Similarly, the direction from the rearward end to the forward end
of each such plug, as indicated by the arrows A in FIGS. 2 and 4,
will be considered as being the forward direction.
Referring first to FIGS. 1 and 2 of the accompanying drawings, it
will be seen that the connector generally designated by numeral 10
is shown in its operative position secured to one end of a coaxial
cable generally designated by numeral 12. The cable 12 comprises an
outer, electrically conductive sheath 13 normally formed of
relatively pure aluminum and an axial core wire electrode 14
normally formed of copper. A closed cell foamed plastic insulation
15 is contained within the outer metallic sheath 13 and serves to
maintain the core electrode 14 axially positioned therein as well
as to insulate the core electrode 14 from the outer sheath 13.
The known connector 10 comprises a tubular metal housing 16, an
intermediate tubular metal sleeve 17 and cap 18. The tubular
housing 16 is externally threaded at its rearward end at 19 for
threaded engagement with a corresponding internal thread 20
provided in the forward end of the tubular sleeve 17. A reduced
diameter portion 21 at the rearward end of the tubular sleeve 17 is
externally threaded at 22 for threaded engagement with a
corresponding internal thread provided in a forwardly extending
skirt 24 of the cap 18. An axial opening 25 is provided through the
cap 18 and, in use, a cable, such as cable 12, extends freely
through such opening 25 into the connector 10.
At its forward end, the tubular housing 16 is provided with a
reduced diameter portion 27 externally threaded at 28 by means of
which the connector 10 may be screwed into a correspondingly
internally threaded opening in a connection or distribution box
(not shown) of any appropriate type. A resiliently compressible
O-ring gasket 29 is usefully provided at the rearward end of the
reduced diameter portion 27 for compression against an external
shoulder 30 of the housing 16 when the plug 10 is secured to such a
distribution box. The gasket 29 functions as a seal to prevent the
entry of dirt and moisture into such a distribution box.
The aforementioned thread 19 extends forwardly along a reduced
diameter portion 32 of the tubular housing 16 and the reduced
diameter portion 32 is forwardly defined by an external shoulder 33
(FIG. 2) which serves to abut the forward end surface of the
tubular sleeve 17 to limit forward movement of that sleeve 17
relative to the housing 16. A resiliently compressible O-ring
gasket 34 is disposed within an external annular recess in the
reduced diameter portion 32 at the forward end of the thread 19 to
provide a seal between the housing 16 and the sleeve 17 when these
members are secured together as actually shown in FIG. 1.
Axially disposed within the housing 16 is a metal collet sleeve 36
shown partly in section in FIG. 1 and which is integrally formed
with an externally projecting metal connecting pin 37 to the
exposed left-hand end of which a wire can be secured, for example,
by soldering, to provide an electrical connection. The right-hand
or rearward end portion of the collet sleeve 36 is hollow and is
formed with a pair of diametrically opposed and axially extending
slots 38 to permit the collet sleeve 36 to be compressed radially
inwardly in a manner to be described into gripping engagement and
electrical contact with an exposed forward end portion 39 of the
core electrode 14. The internal surface of the collet sleeve 36 is
threaded as at 40, serrated or otherwise disturbed to provide
improved gripping with the end portion 39 of the core electrode 14
of the cable 12.
The collet sleeve 36 is maintained in its axial position within the
housing 16 by an electrically insulating bushing 42, an inwardly
projecting annular lip 43 being integrally formed with the reduced
diameter portion 27 of the housing 16 to prevent axially forward
movement of such bushing 42 from within the housing 16.
At its rearward end, the tubular housing 16 is formed with a
rearwardly facing internal frusto-conical cam surface 44 which
diverges radially outwardly in the rearward direction. This cam
surface 44 co-operates with a forwardly facing external
frusto-conical cam surface 45 of a resiliently and radially
inwardly compressible and electrically insulating bushing generally
indicated at 46. An axial bore 47 extends through the bushing 46
and this bore 47 is usefully formed with a bevelled entrance 48 at
its rearward end to facilitate the entry of the forward end of the
core electrode 14 into the rearward end of the collet sleeve 36
which projects into the bore 47.
At its rearward end, the bushing 46 is integrally formed with a
radially extending flange 49 having forward and rearward faces 50
and 51 respectively. The bushing 46 is also formed with an axially
extending radial slot 52 (FIG. 2) to permit the bushing 46 to be
compressed radially inwardly when urged forwardly by means not yet
described as a result of engagement of the forwardly facing
external cam surface 45 of that bushing 46 with the rearwardly
facing internal cam surface 44 of the tubular housing 16. The
aforementioned flange 49 defines an enlarged axial recess 54 within
which, in use, the forward end of the coaxial cable 12 is
received.
A radially inwardly compressible and electrically conductive metal
ferrule generally indicated at 56 is disposed within the tubular
sleeve 17 for axial movement therewithin. This ferrule 56 is formed
with a radially extending forward end surface 57 and a metal washer
58 is disposed between this forward end surface 57 and the
rearwardly facing and radially extending surface 51 of the flange
49 of the bushing 46. An axial bore 59 extends through the ferrule
56 and, in use of the connector 10, a coaxial cable 12 is disposed
within this bore 59. The internal surface of the bore 59 is
threaded, serrated or otherwise disturbed to facilitate gripping
engagement and electrical contact between the ferrule 56 and the
outer conductive sheath 13 of the cable 12 when the ferrule 56 is
radially inwardly compressed into engagement with that sheath 13.
The ferrule 56 is also formed with a rearwardly facing external
frusto-conical cam surface 60 and with an obliquely disposed slot
61 extending through its peripheral wall to facilitate its radially
inward compression into engagement with the outer conductive sheath
13 of the cable 12.
Coaxially disposed around the rearward end of the ferrule 56, there
is provided a thrust ring generally indicated at 64 and having a
radially extending rear surface 65 and a forwardly facing internal
frusto-conical cam surface 66 which, in use, cooperates with the
rearwardly facing external cam surface 60 of the ferrule 56.
Rearwardly of the thrust ring 64, there is disposed within the
tubular sleeve 17 a resiliently compressible cylindrical gasket 67
which is retained between the rear surface 65 of the thrust ring 64
and an internal forwardly facing surface 68 of the cap 18. The
tubular sleeve 17 is also provided with a forwardly facing internal
annular shoulder 69 which serves to restrict rearward movement of
the thrust ring 64 relative to the tubular sleeve 17.
To attach the connector 10 shown in FIGS. 1 and 2 to the forward
end of the coaxial cable 12, the outer conductive sheath 13 and the
foam insulation 15 of that cable are first removed to provide the
exposed forward end portion 39 of the core electrode 14. The cable
12 is then inserted forwardly into the connector 10 with the sleeve
17 and cap 18 of that connector loosened. With the cable correctly
inserted into the connector 10, i.e. with the exposed end portion
39 of the core electrode 14 disposed within the collet sleeve 36
and with the forward end of the outer conductive sheath 13 seated
in the recess 54 of the bushing 46, the sleeve 17 is then tightened
by screwing it onto the housing 16. Such tightening causes forward
axial movement of the sleeve 17 relative to that housing 16.
During such forward movement of the sleeve 17, the internal
shoulder 69 thereof engages the rearwardly facing and radially
extending surface 65 of the thrust ring 64 causing that thrust ring
64 to move forwardly and, as a result of co-action of the internal
cam surface 66 of the thrust ring 64 and the external cam surface
60 of the radially inwardly compressible ferrule 56, ferrule 56
moves forwardly as indicated by the arrow A and is compressed
radially inwardly into gripping engagement and electrical contact
with the outer conductive sheath 13 of the cable 12 disposed
therewithin.
Such forward movement of the ferrule 56 is transmitted through the
washer 58 to the radially inwardly compressible bushing 46 and
resulting co-operative abutment of the forwardly facing cam surface
45 of that bushing 46 with the internal cam surface 44 of the
housing 16 causes the bushing 46 to be radially inwardly compressed
in turn to compress the collet sleeve 36 into gripping engagement
and electrical contact with the exposed forward end portion 39 of
the core electrode 14 of the cable 12.
Finally, the cap 18 is tightened on the sleeve 17 to cause axial
compression and radial expansion of the gasket 67 into sealing
engagement with the sleeve 17 and the outer conductive sheath 13 of
the cable 12 to prevent the entry of moisture and dirt into the
connector 10. It will be understood that electrical connection can
be made to the core electrode 14 through the pin 37 and to the
outer conductive sheath 13 through the metal housing 16.
The operation of the connector 10 shown in FIGS. 1 and 2 utilizes
the relative axial movement of the sleeve 17 and the housing 16 to
cause forward axial movement and radially inward compression of the
sheath-gripping ferrule 56. Such forward axial movement of the
ferrule 56 is transmitted solely in the axial direction through the
washer 58 to the radially compressible bushing 46. Forward axial
movement of the bushing 46 then leads independently to radially
inward compression of that bushing 46 and consequently to radially
inward compression of the collet sleeve 36 axially disposed
therewithin.
Referring now to the second previously known connector shown in
FIGS. 3 and 4 and generally designated by numeral 110, connector
110 is shown secured to one end of the coaxial cable generally
designated by numeral 112.
The connector 110 comprises a tubular metal housing generally
indicated at 116 and a tubular metal sleeve 117 omitted from FIG. 4
and threadedly secured to the rearward end of the housing 116 at
119. A radially compressible, slotted and internally serrated metal
collet sleeve 136 integrally formed with a forwardly extending
connector pin 137 is secured within the housing 116 by an
electrically insulating and fixed bushing 142.
A resiliently and radially inwardly compressible and electrically
insulating bushing generally indicated at 146 is positioned within
the rearward end of the housing 116 but, in distinction to the
corresponding bushing 46 of the connector 10 of FIGS. 1 and 2, the
bushing 146 is not provided with a frustoconical cam surface
corresponding to the cam surface 45 of the bushing 46. Instead, the
bushing 146 includes a generally cylindrical, hollow and forwardly
extending skirt 172. At its rearward end, the skirt 172 is
integrally formed with an annular collar 173 extending radially
inwardly to and integrally formed with a rearwardly extending axial
boss 174 which in turn includes an axial bore 175 within which the
rearward end of the collet sleeve 136 is disposed.
Four equiangularly spaced and radially extending slots 176 are
provided through the walls of the boss 174 and these slots 176
extend partially into the skirt 172 to facilitate radially inward
compression of the boss 174 and consequently of the collet sleeve
136 in a manner to be described.
A radially inwardly compressible and electrically conductive
ferrule generally indicated at 156 is disposed within the sleeve
117 for axial movement therein and this ferrule 156 includes a
radially outwardly extending annular flange 178 at its rearward
end. A forwardly facing annular internal shoulder 179 is formed in
the sleeve 117 and a washer 180 is disposed between the shoulder
179 and a rearwardly facing and radially extending surface 181 of
the aforementioned flange 178 of the ferrule 156. The ferrule 156
is internally threaded or serrated at 159 and is formed with an
axially extending slot 161 through its peripheral wall so that it
can be compressed radially inwardly into gripping engagement and
electrical contact with the outer conductive sheath 113 of the
cable 112.
At its forward end, the ferrule 156 is formed with a forwardly
facing external frusto-conical cam surface 183 which co-operates
with a rearwardly facing internal frusto-conical cam surface 144
formed in the rearward end of the housing 116. A radially inwardly
extending flange 184 is integrally formed with the ferrule 156 at
its forward end and this flange 184 defines an axial opening 185
which, when the connector 110 is assembled as shown in FIG. 3,
receives the aforementioned boss 174 of the bushing 146.
Within the sleeve 117 rearwardly of the washer 180, there is freely
disposed a generally cylindrical metal sleeve 186 and, at the axial
ends of this sleeve 186, resiliently compressible O-ring gaskets
187 and 188 are positioned for the purpose of providing a seal
between the sleeve 117 and the outer conductive sheath 113 of the
cable 112 when the connector 110 is secured to that cable.
For securement of the connector 110 to the forward end of the cable
112, the latter is initially prepared in exactly the same manner as
already described herein with reference to the cable 10 of FIGS. 1
and 2 of the accompanying drawings. The forward end of the cable
112 is inserted into the connector 110 so that the exposed forward
end portion 139 of the core electrode 114 of the cable 112 is
disposed within the collet sleeve 136 and so that the forward end
of the outer conductive sheath 113 of the cable 112 is seated in
the ferrule 156 against the rearwardly facing surface of the flange
184 thereof. The sleeve 117 is then tightened on the housing 116.
During such tightening movement, action of the shoulder 179 on the
rearward end surface 181 of the ferrule 156 through the washer 180
causes forward axial movement of that ferrule 156 as indicated by
the arrow A. The resulting abutment of the forward facing cam
surface 183 of the ferrule 156 with the internal cam surface 144 of
the housing 116 causes radially inward compression of that ferrule
156 into gripping engagement and electrical contact with the outer
conductive sheath 113 of the cable 112. Such radially inward
compression of the ferrule 156 is transmitted through the flange
184 thereof to the boss 174 of the radially inwardly compressible
bushing 146 which is in turn effective to cause radially inward
compression of the collet sleeve 136 into gripping engagement and
electrical contact with the exposed forward end portion 139 of the
core electrode 114.
During such tightening of the sleeve 117 on the housing 116, the
ferrule 156 is initially moved rearwardly within the sleeve 117
relative thereto to compress the O-ring gaskets 187 and 188 into
sealing abutment with the internal surface of the sleeve 117 and
with the outer conductive sheath 113 of the cable 112 until the
washer 180 abuts the aforementioned shoulder 179.
It will now be seen that, in connector 110 shown in FIGS. 3 and 4,
radially inward compression of the collet sleeve 136 onto the
forward end portion 139 of the core electrode 114 is obtained
solely as a result of radially inward compression of the
sheath-gripping ferrule 156.
Having described the previously known connectors 10 and 110 shown
in FIGS. 1, 2 and 3, 4 respectively, two particularly useful
embodiments of a connector in accordance with this invention as
shown in FIGS. 5, 6 and 7 of the accompanying drawings will now be
described.
Referring first to the connector 210 shown in FIG. 5, it will be
seen that this connector 210 includes a tubular metal housing
generally indicated at 216 and a tubular plug bolt generally
indicated at 217. It should perhaps be pointed out that, in
accordance with a particularly useful feature of this invention, a
plug bolt such as the plug bolt 217, is provided in distinction to
the provision of a threaded sleeve such as the sleeves 17 and 117
already described herein. The plug bolt 217 includes a head 218 and
a shank 290 and has an axial bore 225 extending therethrough for
the free insertion of a coaxial cable thereinto.
The plug bolt 217 is threadedly received at 219 in the rearward end
of the housing 216 and a resiliently compressible O-ring gasket 234
is disposed around the shank 290 of the plug bolt 217 to provide a
seal between that plug bolt 217 and the housing 216.
The connector 210 also includes a radially inwardly compressible
collet sleeve 236 which is integrally formed with a forwardly
extending connector pin 237 which in turn is retained in fixed
position within the connector 210 by a bushing generally indicated
at 242 positioned in the forward end of the housing 216. In
distinction to the corresponding bushings 42 and 142 already
described, the bushing 242 is formed from two opposed cup-shaped
members 291 and 292 as will readily be understood by reference to
FIG. 5 of the drawings. At its rearward end, the collet sleeve 236
is hollow and is formed with one or more axially extending slots
(not shown) in its wall and can be threaded or serrated in its
inner surface 240 to permit its radially inward compression into
gripping engagement and electrical contact with an exposed forward
end portion of the core electrode of a coaxial cable (not shown),
to which the connector is to be secured.
Forwardly of the rearward end of the collet sleeve 236, the housing
216 is provided with a rearwardly facing internal annular shoulder
or abutment stop 293 which serves to limit forward axial movement
of a resiliently and radially inwardly compressible and
electrically insulating bushing generally indicated at 246. The
bushing 246 is provided with an axial bore 247 within which a
rearward end portion of the collet sleeve 236 is disposed. The bore
247 is flared outwardly at 248 for the purpose of guiding the
forward end of a core electrode of a cable into that collet sleeve
236.
A sector 291 of the bushing 246 is cut away as will best be seen by
reference to FIG. 6 to facilitate radially inward compression of
the bushing 246 for a purpose which will be more readily understood
as the description herein proceeds. The bushing 246 includes a
radially extending and rearwardly facing surface 254 and a
rearwardly facing annular and external frustoconical cam surface
294.
The connector 210 also includes a radially inwardly compressible
and electrically conductive metal ferrule 256 having an axial bore
usefully provided in its inner surface with a thread or serration
to provide improved gripping engagement with the outer conductive
sheath of a coaxial cable disposed therein. The ferrule 256 has an
axially extending slot 261 in its peripheral wall to facilitate its
radially inward compression into gripping engagement and electrical
contact with the outer conductive sheath of a cable disposed
therein. The ferrule 256 also is formed at its forward end with
forwardly facing frusto-conical internal cam surface 295 for
contiguous surface abutment with the rearwardly facing external
frusto-conical cam surface 294 of the bushing 246. At its rearward
end, the ferrule 256 is formed with rearwardly facing
frusto-conical external cam surface 296 for contiguous surface
abutment with a forwardly facing internal cam surface 266 of an
annular thrust ring 264 disposed for axial movement within the
housing 216 forwardly of the aforementioned thread 219.
In accordance with an optional but particularly useful feature of
this invention, the thrust ring 264 is formed with an external
thread 297 for threaded engagement with the internal thread 219 of
the housing 216. With the provision of such a thread 297 of the
thrust ring 264, that ring can be inserted into the housing 216 for
free axial movement therein by screwing it into that housing after
which time it is restricted against non-rotational rearward axial
movement out of that housing 216. This is particularly advantageous
in that it prevents accidental displacement of the thrust ring 264,
the ferrule 256 and the bushing 246 in the event that the plug bolt
217 is completely removed or unscrewed from the rearward end of the
housing 216.
In accordance with another useful feature of this invention, the
plug bolt 217 of the connector 210 is formed in the forward end of
its axial bore 225 with an axially extending annular seating 298 in
which a resilient gasket seal 299, of rectangular or circular
configuration, e.g., an O-ring, is positioned.
To secure the connector 210 to the forward end of a coaxial cable,
such as the cables 12 and 112 already described herein, the forward
end of the cable is initially prepared in exactly the same manner
as that already described so as to provide an exposed forward end
section of the core electrode of such a cable. The forward end of
the cable is then inserted into the connector 210 until such
exposed forward end portion of the core electrode is positioned
within the collet sleeve 236 and with the forward end of the outer
conductive sheath of the cable seated against the rearwardly facing
surface 254 of the bushing 246. The plug bolt 217 is then screwed
into the housing 216 and, during such screwing of the plug bolt
217, the gasket sleeve 299 is axially compressed and radially
expanded to provide a moisture and dust barrier around the outer
sheath of the cable.
Continued turning of the plug bolt 217 into the housing 216 causes
the forward end of the shank 290 of the plug bolt 217 to abut the
rearwardly facing radial surface of the thrust ring 264 to move
that ring 264 axially forwardly. Such axial forward movement of the
thrust ring 264 through co-action of the internal cam surface 266
thereof with rearwardly facing external cam surface 296 of the
ferrule 256 causes ferrule 256 both to move axially forwardly and
its rearward end to be compressed radially inwardly into gripping
engagement and electrical contact with the outer sheath of the
cable disposed within the connector.
Such forward movement of the ferrule 256, causes bushing 246 to be
radially inwardly compressed, through co-action of the internal cam
surface 295 of ferrule 256 and the rearwardly facing external cam
surface 294 of the bushing 246 such that bushing 246 acts on the
collet sleeve 236 to compress the collet sleeve into gripping
engagement and electrical contact with the core electrode forward
portion disposed therewithin. The outer surface 301 at the forward
end of ferrule 256 is forced radially outwardly by the aforesaid
co-action of internal cam surface 295 of the ferrule 256 and cam
surface 294 of bushing 246 to tightly abut inner surface 303 of
housing 216 and to effectively prevent ferrule 256 from rotating
and twisting the coaxial cable squeezed thereby.
It will now be understood that, for the particular connector 210 in
accordance with this invention as illustrated in FIGS. 5 and 6,
tightening movement is transmitted from the sheath-engagement
ferrule 256 thereof to the bushing 246 associated with the core
electrode-gripping collet sleeve 236, in both the axial and the
radial directions. It is also to be noted that the radially inward
compression applied to the collet sleeve 236 through the
surrounding bushing 246 is applied thereto in the forward direction
and over a greater axial length than was the case for either of the
previously known connectors 10 and 110 hereinbefore described.
Having completed the description of the connector 210 shown in
FIGS. 5 and 6, the structure of the connector generally indicated
at 310 in FIG. 7 will now be considered insofar as it differs from
that of the connector 210. Referring therefore to FIG. 7, it will
be seen that the connector 310 shown therein differs from the
connector 210 only in regard to the structural components provided
for transmitting the tightening forces from a radially compressible
and electrically conductive sheath-gripping ferrule 356 thereof
forwardly to the radially compressible and electrically insulating
bushing 246 coaxially disposed around the radially compressible
collet sleeve 236 of the connector and in regard to the provision
of a resiliently compressible O-ring gasket 399 for providing a
seal between the outer conductive sheath 313 of the cable 312 and
the connector 310. In particular, it will be noted that the O-ring
gasket 399 is positioned within an annular recess 398 provided for
this purpose in the forwardly facing end surface of the shank 390
of the plug bolt 317. Apart from this particular difference, the
structure of the plug bolt 317 is identical to that of the plug
bolt 217 already described herein.
The resiliently and radially inwardly compressible bushing 246 of
the connector 310 is identical to the bushing 246 of the connector
210 but, instead of directly abutting a cam surface formed on the
forward end of the sheath-gripping ferrule 356, the rearwardly
facing external cam surface 294 of the bushing 246 of the connector
310 is disposed in surface abutment with a forwardly facing
internal cam surface 400 of a thrust collar generally indicated at
401 which is also provided with a rearwardly facing internal cam
surface 402 which in turn is in surface abutment with a forwardly
facing external cam surface 403 of the sheath-gripping ferrule
356.
Since the manner in which the connector 310 is used is generally
identical to that of the connector 210 already described, it is
considered to be unnecessary to describe such manner of use in
further detail herein. It should be noted, however, that the
structure shown in FIG. 7 is operative for transmitting radially
inward compressive movement from the sheath-gripping ferrule 356 to
the collet sleeve 236 of the connector via collar 401 and bushing
246. Axial forward movement of ferrule 356 causes collar 401 to
move forward and radially outwardly under the co-action of cam
surfaces 402,403 and 400,294 such that the outer surface 410 of
collar 401 tightly abuts the inner surface 303 of housing 216 to
effectively prevent ferrule 356 from rotating while bushing 246 is
compressed to tightly grip collet sleeve 236. In this respect, the
connector 310 is more similar to the previously known connector 10
of FIGS. 1 and 2 but differs therefrom in that the radially
compressive forces are applied to the core electrode-gripping
collet sleeve over a greater axial length and in the forward
direction rather than in the rearward direction.
It will be understood that numerous modifications and variations
may be made to the structures of the connectors 210 and 310
hereinbefore described without departing from the scope of the
invention. In particular, it can be noted that means such as a
fixed key disposed in an axially extending keyway formed, for
example, in the outer peripheral surface of the ferrule 256 of the
connector 210 of FIG. 5 may be provided to prevent rotation of that
ferrule during tightening of the connector on the end of a coaxial
cable. Alternatively or additionally, means such as a low friction
washer or even a bearing may be incorporated to reduce the
frictional forces between the forward end of the plug bolt 217 and
the rearwardly facing surface of the thrust ring 264 of that
connector.
* * * * *