Information
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Patent Grant
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6793529
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Patent Number
6,793,529
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Date Filed
Tuesday, September 30, 200320 years ago
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Date Issued
Tuesday, September 21, 200419 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
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CPC
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US Classifications
Field of Search
US
- 439 578
- 439 592
- 174 88 C
- 029 747
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International Classifications
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Abstract
An electrical connector for coaxial cable, the connector having a positive stop for a clamp nut. The clamp nut driving a means for compression which sandwiches a leading edge of the coaxial cable outer conductor between the connector body and the means for compression. The positive stop positioned to limit tightening of the clamp nut and thereby compression force upon the flared leading edge of the coaxial cable outer conductor to a desired maximum level. The means for compression, for example a circular coil spring may be deformable, allowing the connector to adapt to varying manufacturing tolerances of each connector component, yet still maintaining the maximum desired compression force limit. Thereby, the connector may be correctly installed without requiring use of a torque wrench to ensure proper compression force.
Description
BACKGROUND OF INVENTION
1. Field of the Invention
This invention relates to electrical cable connectors. More particularly, the invention relates to a coaxial cable connector which clamps the circular outer conductor of the electrical cable; the connector adapted to have a clamp nut with a positive stop at a position corresponding to a desired tightening torque.
2. Description of Related Art
Coaxial cable connectors are used, for example, in communication systems requiring a high level of reliability and precision.
To create a secure mechanical and optimized electrical interconnection between the cable and the connector, it is desirable to have uniform, circumferential contact between a leading edge of the coaxial cable outer conductor and the connector body. A flared end of the outer conductor may be clamped against an annularwedge surface of the connector body, using a clamp nut. Representative of this technology is U.S. Pat. No. 5,795,188 issued Aug. 18, 1998 to Harwath, also owned by applicant, Andrew Corporation and hereby incorporated by reference in the entirety.
To minimize twisting forces upon the outer conductor as the clamp nut is tightened, an opposing thrust collar may be placed between the back side of the flared end of the outer conductor and the clamp nut. To allow the wedge ring to fit over the flared end of the outer conductor an elastic spring, “finger” collar or the like may be used between the thrust collar and the flared end of the outer conductor. Rotation of the clamp nut urges the thrust collar against the spring and the spring against the backside of the flared end of the outer conductor. Thereby, the flared end of the outer conductor is securely sandwiched between the annular wedge surface and the spring.
A connector that is poorly installed may damage equipment, significantly degrade system performance and or lead to premature system failure. Therefore, prior connectors typically include extensive installation instructions that require costly specialized tools.
Threaded connections on and between connectors are typically tightened using wrenches having the potential for large moment arm force generation that may damage the connector and or associated cable(s). Therefore, use of a torque wrench with a torque setting specific to each connector is often specified by the prior connector installation instructions. Applying the proper torque, which may vary depending upon the dimensions of the specific connector and cable materials, for example 20-30 foot-pounds, to threaded connections ensures correct electrical interconnection and prevents application of excessive force that may deform or otherwise damage threads, seals and or the relatively soft metal(s) of the cable(s). The torque wrench is a costly and easily damaged tool that the installation personnel may not always have on hand or bother to use correctly, if at all. Also, connectors may be installed in exposed locations such as the top of radio towers where installation personnel may be less inclined to properly follow time-consuming installation procedures.
Competition in the coaxial cable connector market has focused attention on minimization of overall costs, including training requirements for installation personnel, reduction of dedicated installation tooling and the total number of required installation steps and or operations.
Therefore, it is an object of the invention to provide a connector that overcomes deficiencies in the prior art.
BRIEF DESCRIPTION OF DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention.
FIG. 1
is a partial cut-away side view of a coaxial connector according to one embodiment of the invention, installed upon a coaxial cable, the clamp nut.
FIG. 2
is a partial cut-away side view of the coaxial connector of
FIG. 1
, with the clamp nut fully tightened, seated against the positive stop.
DETAILED DESCRIPTION
As shown in
FIGS. 1 and 2
, a connector
1
for use with a coaxial cable
5
has a clamp nut
10
adapted to fit over an end portion of the cable
5
. A sheath
15
of the cable
5
is removed from the end of the cable
5
to expose the outer conductor
20
. Threads
25
between the clamp nut
10
and the connector body
35
operate to drive a thrust collar
27
into a circular coil spring
30
to clamp a flared leading edge
26
of the outer conductor
20
between the circular coil spring
30
and an annular wedge surface
33
of the connector body
35
, to secure the connector
1
to the cable
5
. The clamping action creates a compression force that is distributed evenly around the annular wedge surface
33
to create a uniform electrical and mechanical interconnection between the connector body
35
and the outer conductor
20
.
The connector
1
may be supplied with environmental seals to prevent fouling and or moisture infiltration into the connector
1
and or coaxial cable
5
. A stop o-ring
37
seals between the outer-radius of the clamp nut
10
and the connector body
35
; an outer-conductor o-ring
39
seals between the clamp nut
10
and the outer conductor
20
. Further, an inner conductor o-ring
41
seals between the inner conductor
45
and an inner contact
47
coaxially located within the connector
1
by an insulator
49
.
Over tightening of the clamp nut
10
onto the connector body
35
which may generate compression and or shearing forces at damaging levels is prevented by a positive stop configured, for example, between a back end
50
of the connector body
35
and a shoulder
52
of the clamp nut
10
. One skilled in the art will recognize that other variations of the positive stop are possible, for example shoulder to shoulder and reversal of the end to stop, etcetera; the limitation being that when reached, the positive stop prevents further threading between the connector body
35
and the clamp nut
10
. The relative location upon the connector
1
of the positive stop is adapted to a position where the clamp nut
10
is threaded to the connector body
35
to clamp the flared leading edge
26
of the outer conductor
15
at a desired maximum compression force level. The circular coil spring
30
may be configured to have an acceptable range of deformation prior to collapse to accommodate manufacturing tolerances of the associated connector
1
components and an expected thickness range of the outer conductor
20
flared leading edge
26
.
The prior art discloses a range of known equivalents for the circular coil spring
30
. For example, U.S. Pat. No. 5,795,188, discloses embodiments replacing the circular coil spring
30
with a clamping ring having a plurality of beads or wedge segments. Further alternatives include a thrust collar or separate ring with a plurality of spring fingers capable of bending to allow initial placement over the flared leading edge
26
but which then either spring down or are forced down by either the clamp nut
10
or connector body
35
to allow the fingers to be compressed against the back side of the flared leading edge
26
. One skilled in the art will appreciate that any means for compression that is configured for placement around the back side of the flared leading edge
26
may be applied and then used to retain the flared leading edge
26
against the annular wedge surface
27
of connector body
30
as the clamp nut
10
is tightened.
Preferably, the selected means for compression has a limited deformation characteristic short of a collapse and or crush force level to allow for an increased range of associated component manufacturing tolerances. The limited deformation characteristic may be varied to adapt for observed manufacturing tolerances, for example, by varying the selected material, the configuration of the means for compression and or the thickness of the selected material. The selected limited deformation characteristic may be adapted to provide a desired range of additional compression “slack” before the positive stop is reached, allowing use of overall manufacturing cost saving decreased precision in the manufacturing process but still ensuring that each connector assembly will reach the desired compression force when the positive stop is reached, even if the components of an individual connector each happen to be on the short side of the allowable manufacturing tolerance. In the embodiment of
FIG. 1
, the means for compression is the circular coil spring
30
. The circular coil spring
30
may be adapted to have the desired limited deformation characteristic by selecting an appropriate material such as steel and a desired material thickness wherein the circular coil spring
30
will partially deform over a desired compression force range before either collapsing or transmitting a damaging out of range compression force to the flared leading edge
26
of the outer conductor
20
.
In further embodiments, the overlap between the clamp nut
10
and the connector body
35
may be reversed. That is, rather than the connector body overlapping the clamp nut
10
as shown in
FIG. 1
, the relative positions of the components may be reversed, for example as shown in U.S. Pat. No. 5,795,188. The compression force generation between the components remains the same in either configuration.
In use, the cable
5
end is prepared and the clamp nut
10
placed over the cable end along with any applicable outer conductor o-ring
39
and thrust collar
27
. The circular coil spring
31
or other means for compression is then stretched over the flared leading edge
26
into position behind the flared leading edge
26
. If used, the stop o-ring
39
is placed upon the clamp nut
10
proximate the shoulder
52
. The connector body
35
is then located so that the inner contact
47
engages the inner conductor
45
and the annular wedge surface
33
is pressed against the front side of the flared leading edge
26
. The clamp nut
10
is then moved toward the connector body
30
and threaded into the threads
25
as shown in FIG.
1
. The clamp nut
10
is threaded until the back end
50
of the connector body
30
reaches the positive stop at the shoulder
52
of the clamp nut
10
as shown in FIG.
2
. Reaching the positive stop signifies to the installation personnel that the desired compression force has been reached without requiring use of a torque wrench and prevents further tightening of the clamp nut
10
which would increase the compression force beyond the desired maximum level.
One skilled in the art will appreciate that the connector
1
may be adapted to mate with the dimensions and configuration of a specific coaxial cable
5
, for example a coaxial cable
5
with annular or helical corrugations in the inner and or outer conductors
47
,
20
. To mate with a circular coil spring
30
or the like adapted for use with outer conductor(s)
20
having helical corrugations, the thrust collar
27
may be formed with a step located at a point where the circular coil spring
30
bridges across the corrugations. Further, the connector end
55
of the connector
1
may be adapted to mate according to male and or female embodiments of a proprietary interface or one of the standard connector types, for example BNC, Type-N or DIN.
The present invention provides coaxial connectors with ease of installation features and reduces specialized installation tool requirements. Also, protection from damaging excess torque application during connector installation and elimination of the need for torque wrenches is built into the connector
1
.
TABLE OF PARTS
|
Table of Parts
|
|
|
1
connector
|
5
coaxial cable
|
10
clamp nut
|
15
sheath
|
20
outer conductor
|
25
threads
|
26
flared leading edge
|
27
thrust collar
|
30
circular coil spring
|
33
annular wedge surface
|
35
connector body
|
37
stop o-ring
|
39
outer-conductor o-ring
|
41
inner-conductor o-ring
|
45
inner conductor
|
47
inner contact
|
49
insulator
|
50
back end
|
52
shoulder
|
55
connector end
|
|
Where in the foregoing description reference has been made to materials, ratios, integers or components having know equivalents then such equivalents are herein incorporated as if individually set forth.
While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specifoci details, representative apparatus, methods, and illustrative example shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of applicat's general inventive concept. Futher, it is to be appreciated that improvements and/or modifications may be made thereto without departing from the scope or spirit of the present invention as defined by the following claims.
Claims
- 1. A coaxial connector for use with a coaxial cable having an outer conductor, comprising:a clamp nut adapted to fit over the outer conductor, the clamp nut having threads that mate with corresponding threads on a connector body; a circular coil spring adapted to fit over a flared leading edge of the outer conductor; the connector body having an annular wedge surface adapted to mate with the flared leading edge of the outer conductor; the threads drawing the clamp nut towards the connector body, driving the circular coil spring to exert a compression force that urges the flared leading edge into contact with the annular wedge surface; a surface to surface positive stop between the clamp nut and the connector body that stops the compression force at a predetermined maximum torque by preventing further movement of the clamp nut towards the connector body.
- 2. The connector of claim 1, wherein the positive stop is formed by contact between a back end of the connector body and a shoulder formed in the clamp nut.
- 3. The connector of claim 1, further including a thrust collar positioned between the clamp nut and the circular coil spring, whereby the clamp nut drives the thrust collar into the circular coil spring.
- 4. The connector of claim 1, further including a stop o-ring positioned between the connector body and the clamp nut.
- 5. The connector of claim 1, further including an outer conductor o-ring positioned between the outer conductor and the clamp nut.
- 6. The connector of claim 1, further including an inner contact positioned coaxially within and electrically isolated from the connector body by an insulator.
- 7. The connector of claim 1, further including one of a BNC, Type-N and a DIN interface at a connector end of the connector body.
- 8. A coaxial connector for use with a coaxial cable having an outer conductor, comprising:a clamp nut adapted to fit over the outer conductor, the clamp nut having threads that mate with corresponding threads on a connector body; a means for compression adapted to fit over a flared leading edge of the outer conductor; the connector body having an annular wedge surface adapted to mate with the flared leading edge of the outer conductor; the threads drawing the clamp nut towards the connector body, driving the means for compression to exert a compression force that urges the flared leading edge into contact with the annular wedge surface; a surface to surface positive stop between the clamp nut and the connector body that stops the compression force at a predetermined maximum torque by preventing further movement of the clamp nut towards the connector body.
- 9. The connector of claim 8, wherein the positive stop is formed by contact between a back end of the connector body and a shoulder formed in the clamp nut.
- 10. The connector of claim 8, further including a thrust collar positioned between the clamp nut and the means for compression, whereby the clamp nut drives the thrust collar into the circular coil spring.
- 11. The connector of claim 8, wherein the means for compression has a limited deformation characteristic.
- 12. The connector of claim 8, wherein the means for compression is one a circular coil spring, a ring having a plurality of beads, a ring having a plurality of wedge segments, a ring with a plurality of spring fingers and spring fingers formed in the clamp nut.
- 13. A coaxial connector for use with a coaxial cable having an outer conductor, comprising:a clamp nut adapted to fit over the outer conductor, the clamp nut having threads that mate with corresponding threads on a connector body; a circular coil spring adapted to fit over a flared leading edge of the outer conductor; the connector body adapted to engage the outer conductor; the threads drawing the clamp nut towards the connector body, driving the circular coil spring to exert a compression force that urges the outer conductor into contact with the connector body a surface to surface positive stop between the clamp nut and the connector body that stops the compression force at a predetermined maximum torque by preventing further movement of the clamp nut towards the connector body.
- 14. The connector of claim 13, wherein the positive stop is formed by contact between a back end of the connector body and a shoulder formed in the clamp nut.
- 15. The connector of claim 13, further including a thrust collar positioned between the clamp nut and the circular coil spring, whereby the clamp nut drives the thrust collar into the circular coil spring.
- 16. A method for attaching a coaxial connector to a coaxial cable having an outer conductor, comprising the steps of:placing a clamp nut over a cable end; stretching a circular coil spring over a flared leading edge of the cable end; mating a connector body to the cable end; threading the clamp nut to the connector body until a threading the clamp nut to the connector body until a surface to surface positive stop is reached; the threading urging the clamp nut against the circular coil spring against the flared leading edge against the connector body, creating a maximum predetermined compression force of the flared leading edge onto the connector body.
US Referenced Citations (11)