U.S. patent number 3,883,681 [Application Number 05/425,357] was granted by the patent office on 1975-05-13 for anchor assembly for strength member of communication cable.
This patent grant is currently assigned to The United States of America as represented by the Secretary of the Navy. Invention is credited to Robyn M. Campbell.
United States Patent |
3,883,681 |
Campbell |
May 13, 1975 |
Anchor assembly for strength member of communication cable
Abstract
An improved interconnection between a structural member and a
shielded coal cable reduces the possibility of there being created
uneven, failure inducing, tensile stresses. An elongate fitting
member is provided with a passageway for electrical or fiber-optic
conductors and is sized to be fitted within the coaxially disposed
braided shielding. A cylindrically-shaped retaining member is
shaped with a bore having dimensions slightly in excess of the
combined diameter of the fitting member and thickness of the
braided shielding. As the cable is brought under tension, a slight
constriction of the braided shielding occurs. This constriction
results in a uniform gripping force along the length of the fitting
member. A radially extending rim on the innermost extension of the
fitting member is brought to bear against the innermost extension
of the retaining member and the cable is anchored in place. The
coaction of the aforedescribed elements ensures high reliability
since there are uniform stresses exerted and no failure-inducing
load concentrations.
Inventors: |
Campbell; Robyn M. (San Diego,
CA) |
Assignee: |
The United States of America as
represented by the Secretary of the Navy (Washington,
DC)
|
Family
ID: |
23686201 |
Appl.
No.: |
05/425,357 |
Filed: |
December 17, 1973 |
Current U.S.
Class: |
174/669; 174/653;
385/136; 174/89 |
Current CPC
Class: |
G02B
6/3887 (20130101); G02B 6/3897 (20130101); G02B
6/4429 (20130101); H02G 3/0658 (20130101) |
Current International
Class: |
H02G
3/06 (20060101); H02G 3/02 (20060101); G02B
6/44 (20060101); G02B 6/38 (20060101); H02g
003/06 () |
Field of
Search: |
;174/35C,65R,65SS,7R,75C,89,151 ;350/96B,96C |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Askin; Laramie E.
Attorney, Agent or Firm: Sciascia; Richard S. Johnston;
Ervin F. Keough; Thomas Glenn
Government Interests
STATEMENT OF GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or
for the Government of the United States of America for governmental
purposes without the payment of any royalties thereon or therefor.
Claims
What is claimed is:
1. A secure mechanical interconnection comprising:
a wall member having an opening therethrough;
a coaxial cable having at least one axially extending conductor of
electromagnetic energy, insulation covering said conductor, an
elongate braided conductive shielding coaxially disposed about said
insulation and an elongate flexible covering coaxially carried on
said shielding, said cable extending through said opening in said
wall member;
a rigid elongate tubular-shaped member having an inner diameter
sized to contain and containing said conductor therethrough and
further having an outer diameter sized to fit and fitting within
said braided conductive shielding in a slidable relationship, said
elongate tubular-shaped member being provided with an annular
rounded shoulder at one end and a radially extending rim at its
opposite end and;
a rigid cylindrically-shaped member coaxially carried on said rigid
elongate tubular-shaped member by having a coaxial bore sized to
fit about said tubular-shaped member and said braided conductive
shielding, said cylindrically-shaped member being configured with
oppositely facing ends for mechanically engaging an inner surface
of the wall member and said radially extending rim of said
tubular-shaped member, as a tensile force is exerted on said
coaxial cable, said braided conductive shielding uniformly gripping
said elongate tubular-shaped member along the surfaces defined by
said outer diameter and said rounded shoulder and said radially
extending rim bearing against one oppositely facing end of said
rigid cylindrically-shaped member to transfer the tensile force to
the wall member via the other oppositely facing end of said rigid
cylindrically-shaped member.
2. A secure mechanical interconnection according to claim 1 further
including:
a gland fitting mounted in said opening of said wall member being
sized to receive and receiving said coaxial cable therethrough for
ensuring a watertight interconnection.
Description
BACKGROUND OF THE INVENTION
Routinely, engineers and technicians provide auxiliary supporting
lines for fiber-optics or electrical cables. In some instances, the
added weight of the auxiliary line in a data transfer or power
supply system has seriously impaired the system's ability to
function properly. Particularly in the case of an electrical or an
electronic system, the added bulk and weight of coaxial cables have
increased this problem. While the coaxial cables avoid the problems
associated with cross talk and the data transfer capability is
increased substantially, excessive weight remains a primary design
problem. Noteworthy attempts have been made to meet this problem by
including appropriately configured connectors at suitable intervals
and at opposite ends of the coaxial link. Most of these connectors
use clamping arrangements or a variety of flange-and-cone
combinations to couple the braided shields to structural members.
In all of these connectors there is created certain critical areas
where the braided shielding is subjected to concentrated tensile or
torsional stresses. Therefore, along these areas it is not uncommon
for failure to occur, especially where towed sensors or suspended
loads need be borne. Furthermore, those connectors using above
referred to approaches and also seeking to avoid the creation of
high-stress areas on the shielding are needlessly complex. Such
connectors are fabricated from a number of machined components and,
consequently, their per unit cost is raised and their reliability
is impaired. There is a continuing need in the state-of-the-art for
an uncomplicated coaxial cable connector which is inexpensive and
highly reliable.
SUMMARY OF THE INVENTION
The present invention is directed to providing an improved
interconnection between a coaxial cable and a structural member. An
elongate fitting member is inserted between an electrical conductor
and its coaxially disposed braided shield and a retaining member is
fitted over the fitting member and shield. Since the internal bore
of the retaining member is only slightly larger than the diameter
of the fitting member and the thickness of the coaxially disposed
braided shield, there is effected a uniform tensile stress on each
of the wires of the braided shield, thereby resulting in increased
reliability at a minimum complexity.
It is a prime object of the invention to provide an improved
connector for a coaxial cable.
Yet another object is to provide a coaxial cable connector or
reduced complexity.
Another object is to provide a coaxial cable connector employing
its braided shielding as the load bearing member and which does not
introduce excessive, localized stress.
Still another object is to provide a connector which is readily
installed.
Still another object is to provide a connector suitable for
electric, metallic conductors or fiber-optic conductors.
These and other objects of the invention will become more readily
apparent from the ensuing specification when taken with the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isomeric exploded view of the invention.
FIG. 2 is a longitudinal cross-sectional view of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings, there is shown a preferred
embodiment of a connector 10 mounted in place on a structural
member 11, such as a wall or bulkhead. The connector is so disposed
to serve as an anchor point for a cable 12, the primary purpose of
which is to transfer electromagnetic energy.
The details of the connector are more clearly depicted in FIG. 2 of
the drawings. Here, the cable is disposed to function as a load
bearing member for a towed sensor trailing from the left side.
Conductors 13, either metallic or fiber optic, bidirectionally
couple power and data to and from machinery and instrumentation at
opposite ends of the cable. The conductors positioned and protected
by a dielectric, fibrous packing 14 are in widespread use in cables
of this type. A coaxial, braided shielding 15 covers the conductors
and packing and is routinely so disposed to serve its primary
purpose, that being to prevent remotely originating spurious
signals from being picked up by metallic conductors 13. In a
secondary role, the braided shielding functions to protect the
conductors and is woven in a conventional pattern from a number of
alloy wires. Lastly, a flexible plastic-like or rubber covering 16
ensures that the watertight integrity of the cable is not
impaired.
Where the cable approaches structural member 11, it is first fed
through a gland 17 of conventional design. A popular type of gland
includes a first lock nut threaded into the structural member. A
second lock nut is tightened and forces a collar into a grommet.
The grommet is deformed by the collar and is brought to bear
against the outer surface of either covering 16 or coaxial braided
shielding 15. The main purpose of the gland is to seal the
connection although it does partially act in a secondary role as a
connector or a retainer of the cable.
The cable, having passed through structural member 11, now
protrudes away from its inner wall. Packing 14 is removed from the
inside of a protruding portion 15a of coaxial braided shielding 15.
With the packing removed there is now defined a
cylindrically-shaped void between the shielding and the conductors.
A fitting member 18 is sized to fit within the cylindrically-shaped
void and is shaped with a coaxial passageway for receiving the
conductors. The outer surface of an elongate portion 19 of the
fitting member has a diameter being slightly in excess of the inner
diameter of coaxial braided shielding 15. When the elongate portion
is inserted therein, the braided shielding lightly grips it
uniformly along its entire length. Because a first end of the
fitting member is formed with a rounded shoulder 20, it is a
relatively simple matter to insert the fitting member within the
braided shielding. The configuration of the rounded shoulder also
prevents the build-up of excessive stresses when the cable is under
tension. At the opposite end of the fitting member a radially
extending rim 21 limits the degree of longitudinal travel in the
braided shielding and helps to engage the shielding in a manner to
be explained below.
An essentially cylindrically-shaped retaining member 22 is provided
with a coaxial bore 23 having a diameter which is slightly in
excess of the diameter of elongate portion 19. Since the coaxial
bore is so dimensioned, a small shell-shaped space is formed within
which protruding portion 15a of the braided shielding is contained
to be held adjacent elongate portion 19.
When a load pulls from left to right on cable 12, see FIG. 2,
protruding portion 15a of the coaxial braided shielding uniformly
constricts along the outer surface of elongate portion 19 to engage
the fitting member. The resultant constricting force is uniform
along the elongate outer surface and the aforedescribed rounded
shoulder avoids the creation of an area of high stress where the
coaxial braided shielding engages the fitting member. Because of
the shielding's gripping, the load is coupled to fitting member 18.
This causes the fitting member to be pulled toward retaining member
22. Flat, opposite ends 24 of the retaining member abut against the
inner surface wall of structural member 11 and radially extending
rim 21 of the fitting member and the load is transferred to the
structural member.
There is no clamping of the braided shielding or otherwise uneven
transfer of the load through the aforedescribed elements. The ease
of assembly of the disclosed connector enables a rapid electrical
coupling of the conductors to a load bearing structural member.
Because of the few easily machined parts involved, this connection
is inherently trouble-free.
In this invention the well known high strength capabilities of
finely drawn metal alloys used as electrical shielding are utilized
to function as the load bearing member for a coaxial cable. This
high strength capability is not compromised at the connector, due
to the novel configuration and coaction of the disclosed invention.
The sound engineering considerations embraced by this invention
have produced a connector which is more reliable and less expensive
than contemporary connectors.
Obviously, many modifications and variations of the present
invention are possible in the light of the above teachings, and, it
is therefore understood that within the scope of the disclosed
inventive concept, the invention may be practiced otherwise than
specifically described.
* * * * *