U.S. patent number 3,778,749 [Application Number 05/194,879] was granted by the patent office on 1973-12-11 for connector.
This patent grant is currently assigned to Minnesota Mining and Manufacturing Company. Invention is credited to Henry K. Kapell.
United States Patent |
3,778,749 |
Kapell |
December 11, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
CONNECTOR
Abstract
A connector for making electrical connection between an
externally jacketed conductive shield on a communication cable and
a conductor. The vise-like connector includes a pair of resilient
opposed plate-like jaws formed with barbs along tapered projecting
portions and adapted to be clamped in engagement with an end of the
externally jacketed shield.
Inventors: |
Kapell; Henry K. (Mahtomedi,
MN) |
Assignee: |
Minnesota Mining and Manufacturing
Company (St. Paul, MN)
|
Family
ID: |
22719229 |
Appl.
No.: |
05/194,879 |
Filed: |
November 2, 1971 |
Current U.S.
Class: |
439/411; 174/88R;
174/78; 439/99 |
Current CPC
Class: |
H01R
4/646 (20130101) |
Current International
Class: |
H01R
4/64 (20060101); H01r 009/06 (); H02g 015/08 () |
Field of
Search: |
;174/78,88R
;339/95R,95P,97R,97P,98,99
;24/125R,85R,87R,243B,243FS,263A,263LS,259PS |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
herr et al., German Printed Pat. Application No. H22,583, printed
May 3, 1956..
|
Primary Examiner: Clay; Darrell L.
Claims
I claim:
1. A connector for making electrical connection between a conductor
and a jacketed electrically conductive shield on a communication
cable, said connector comprising:
a resilient plate-like conductive first jaw having a base portion,
and a relatively flexible elongate symmetrically tapered projecting
portion extending from said base portion and terminating in a
smaller end, said elongate projecting portion being arcuate about
an axis transverse to the width thereof to form a cylindrically
concave contact surface adapted for engagement with the inner
surface of said shield and having a multiplicity of linear spaced
slits oblique to and extending inwardly from its converging edges
to form triangular barbs, with each of said barbs being curved to
protrude from said contact surface with the point thereof directed
generally away from said smaller end;
a resilient plate-like second jaw having a base portion, and an
elongate symmetrically tapered projecting portion extending from
said base portion and terminating in a smaller end, the projecting
portion of said second jaw being domed to define a concave contact
surface adapted for engagement with the outer surface of the jacket
on said communication cable in aligned opposed relationship with
said contact surface of said first jaw and having a multiplicity of
linear spaced slits oblique to and extending inwardly from its
converging edges to form triangular barbs, with each of said barbs
being curved to protrude from said concave contact surface with the
point thereof directed generally away from the smaller end, the
projecting portion of said second jaw being of essentially the same
length as the projecting portion of said first jaw and being
sufficiently wide to extend over the projecting portion of said
first jaw along each converging edge by approximately the width of
said barbs formed on said second jaw; and
means coupled only between said base portions for connecting said
first jaw to said conductor and to said second jaw, and for
pressing said jaws into contact with a section of the jacketed
shield to engage said barbs and to deflect the projecting portion
of said first jaw.
2. A connector useful in making an electrical connection between a
conductor and a jacketed electrically conductive shield on a
communication cable, said connector comprising:
a resilient plate-like conductive first jaw having a base portion
and a relatively flexible elongate tapered projecting portion
extending from the base portion and terminating in a smaller end,
said elongate projecting portion being arcuate about an axis
transverse to the width thereof to form a cylindrically concave
contact surface adapted for engagement with the inner surface of
said shield and having a plurality of spaced slits formed along
each edge and extending inwardly from said edges away from the base
portion at an angle of between 15.degree. to 45 .degree. with the
edge to form triangular barbs, with each of said barbs being curved
to protrude from said contact surface with the point thereof
directed generally away from said smaller end;
a resilient plate-like second jaw having a base portion and a
projecting portion extending from the base portion and defining a
contact surface adapted for engagement with the outer surface of
the jacket on said communication cable in aligned opposed
relationship with said contact surface of said first jaw, said
projecting portion of said second jaw being wider than
corresponding portions of the projecting portion of said first jaw;
and
means coupled only between said portions for connecting said first
jaw to said conductor and to said second jaw and for pressing said
jaws into contact with a section of the jacketed electrically
conductive shield to engage said barbs with said shield and to
deflect the projecting portion of said first jaw.
3. The connector of claim 2 wherein the projecting portion of said
second jaw is tapered toward a smaller end opposite the base
portion thereof, and has a multiplicity of linear spaced slits
oblique to and extending inwardly from its converging edges to form
triangular barbs positioned along its converging edges, each of
said barbs being curved to protrude from said contact surface with
the point thereof directed generally away from said smaller end;
and the projecting portion of said second jaw is wider than the
corresponding projecting portion of said first jaw by approximately
the width of said barbs formed on said second jaw.
4. The connector of claim 4 wherein the barbs on said first and
second jaws are formed in spaced relationship along corresponding
edges to position the barbs on each jaw generally in the interstice
between barbs on the opposing jaw.
Description
BACKGROUND OF THE INVENTION
This invention relates to electrical connectors of the type
disclosed in U.S. Pats. No. 3,499,972, 3,253,247 and 3,594,691 for
making an electrical connection between a conductor and the
conductive shield on a communication cable.
A communication cable commonly comprises a number of individually
insulated wires which may be bound together with an electrically
insulating inner sheath, a sleeve-like electrically conductive
shield around the wires, and an electrically insulating outer
jacket over the shield. When splicing or terminating the wires, a
reliable electrical connection must be made between a conductor and
the conductive shield to carry an electrical path across the splice
or connect the shield to a source of ground potential to afford
grounding of currents from extraneous electrical fields such as
lightning.
Some prior art connectors for making such a connector which provide
positive mechanical clamping to engage the connector with the
conductive shield have required time consuming preparation of the
conductive shield or outer jacket, such as notching the conductive
shield and jacket as required for use of the connector disclosed in
U.S. Pat. No. 3,499,972, or stripping a portion of the outer jacket
from about the conductive shield as required for use of the
connector disclosed in U.S. Pat. No. 3,253,247. The connector
disclosed in U.S. Pat. No. 3,594,691 includes an elongate
plate-like contact member formed with in-line rows of spurs
projecting from a contact surface and angled toward a first end of
the contact member. This connector is attached to a shield by
positioning the contact member beneath the conductive shield with
the spurs in contact therewith, pulling the first end of the member
to draw the spurs into contact with the conductive shield, and
maintaining the contact by bending the first end of the contact
member about the end of the conductive shield. This connector,
however, does not afford mechanical clamping to maintain positive
contact between the spurs and the conductive shield.
SUMMARY OF THE INVENTION
A connector according to the present invention provides and
maintains a mechanically strong and electrically efficient
grounding connection with a jacketed section of an electrically
conductive shield on a communication cable without the time
consuming preparation of the shield or jacket. The vise-like
connector includes a resilient conductive plate-like first jaw
having a tapered projecting portion which may be inserted beneath
the conductive shield of a communication cable. The projecting
portion is formed along its converging edges with a series of barbs
oriented for engagement with the inner surface of the conductive
shield to effect an efficient electrical connection and the points
of the barbs project away from the smaller end to restrict
extraction of the first jaw. The connector also includes a
resilient second jaw having a projecting portion for contacting the
outer surface of the jacket surrounding the shield. The connector
includes clamping means for clamping the jaws in opposed
relationship on the end of the jacketed conductive shield. The
clamping means slightly deforms the resilient jaws so that an
electrically efficient and mechanically strong connection will be
maintained despite slight deformation of the jacket caused by
continued application of the clamping force.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be further described with reference to the
accompanying drawings wherein like numbers refer to like parts in
the several views, and wherein:
FIG. 1 is a horizontal view of a connector according to the present
invention shown attached between a conductor and a jacketed section
of the conductive shield of a sectioned communication cable
fragment;
FIG. 2 is a fragmentary vertical sectional view partially in
section of a pair of connectors according to the present invention
each shown attached to a woven conductor and to a jacketed
conductive shield section on separate communication cables to
provide a continuous electrical path for the shields over a splice
between the cables;
FIG. 3 is a horizontal plan view of a connector according to the
present invention;
FIG. 4 is a bottom view of the connector shown in FIG. 3;
FIG. 5 is a right end view of the connector shown in FIG. 3;
and
FIG. 6 is a perspective, exploded view of a connector according to
the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 and 2, there is illustrated a connector 10
according to the present invention. The connector 10 is shown
engaged with an end of a conductive shield 12 and outer jacket 14
of a communication cable 16 to afford electrical contact between
the conductive shield 12 and a woven conductor 18. The conductor 18
may be attached to a source of ground potential or may be a portion
of an electrical path around a splice between separate lengths of
communication cable 16 as shown in FIG. 2.
The communication cable 16 comprises a series of individually
insulated wires 20 which may, as illustrated, be surrounded by an
electrically insulating inner sheath 22, a sleevelike conductive
shield 12 around the wires 20 and inner sheath 22, and the
electrically insulating tubular outer jacket 14.
The connector 10, best seen in FIGS. 3 through 6 is vise-like
comprising a pair of resilient elongate plate-like jaws 28 and 30
each having a projecting portion 32 and 34 respectively adapted for
engagement in aligned opposed relationship with a jacketed section
of the conductive shield 12. The connector 10 includes clamping
means or a bolt 36 and a nut 38 for connecting the jaws 28 and 30
together and to the conductor 18, and for pressing the projecting
portions 32 or 34 into contact with a section of the jacketed
conductive shield to slightly deflect the resilient jaws 28 and 30
so that firm clamping engagement will be maintained despite changes
that may occur in the thickness of the jacketed conductive shield
section engaged by the clamp 10.
The projecting portion 32 of the first jaw 28 is designed for
insertion axially beneath the conductive shield 12 of a
communication cable 16 at an end of the conductive shield 12, for
affording efficient electrical connection between the jaw 28 and
the shield 12 and for restricting removal of the jaw 28 subsequent
to insertion.
The jaw 28, best seen in FIGS. 4 and 6 is formed of a resilient
highly conductive metal such as one-half hard cartridge brass or
beryllium-copper. The jaw 28 has a base portion 40 to which the
bolt 36 may be anchored as by staking. The base portion 40 is
slightly curved about a lengthwise axis to conform to the contour
of the inner sheath 22. The projecting portion 32 is symmetrically
tapered along its length to a smaller generally pointed end 42 and
defines a contact surface 44. The contact surface 44 is adapted for
engagement with the inner surface of the shield 12. A multiplicity
of barbs 46 are formed along the converging edges of the projecting
portion 32. Each barb 46 is curved to protrude from the contact
surface 44 with the points of the barbs 46 being directed generally
away from the end 42. The barbs 46 afford piercing engagement with
a conductive shield 12 to insure efficient electrical connection
therewith despite coatings such as oxides or the thin layer of
polyethylene often present on the shield 12. The configuration of
the projecting portion spaces the barbs 46 with respect to the
width of the jaw 28. Upon insertion of the projecting portion 32
beneath a conductive shield 12, the point of each barb 46 will
trace a separate line of contact against the shield 12 due to the
biasing typically caused by the snug fit of the wires 20 and any
inner sheath 22 within the shield 12. This affords piercing by the
barbs 46 of protective coatings or oxides on the shield 12 while
restricting gouging of the shield 12 as might occur upon passage of
successive barbs along the same line of contact. The projecting
portion 32 may also be formed with a series of transversely
extending ridges 48 along the surface 44 to afford a slight filing
of the inner surface of the conductive shield upon insertion of the
projecting portion 32 to remove coatings or oxides and afford good
electrical connection. The projecting portion 32 is slightly curved
about a transverse axis to provide a cylindrically concave contact
surface 44 so that the barbs 46 and contact surface 44 will attain
full length engagement and generally uniform pressure contact with
the inner surface of the conducting shield 12 upon deflection of
the jaw 28 when the connector 10 is clamped onto a jacketed
conductive shield section.
The projecting portion 34 of the second jaw 30 is designed for
engagement with the exterior surface of the outer jacket 14, in
aligned opposed relationship with the contact surface 44 of the
first jaw 28.
The jaw 30, best seen in FIGS. 3-6 is formed of a resilient
material such as one-half hard brass or stainless steel. The jaw 30
is similar in structure to the jaw 28, having a base portion 50
formed with an opening 52 to receive the bolt 36. The projecting
portion 34 is symmetrically tapered to a smaller end 56 and defines
a contact surface 54 adapted for engagement with the outer surface
of the jacket 14 on a communication cable 12. A multiplicity of
barbs 58 are formed along the converging edges of the projecting
portion 34. The barbs 58 are curved to protrude from the contact
surface 54 with the points of the barbs 58 directed away from the
smaller end 56. This positioning of the barbs 58 affords piercing
engagement of the barbs 58 with the outer surface of the jacket 14
to restrict removal of the jaw 30 by longitudinal forces applied
toward the base portion 50.
The projecting portions 32 and 34 are generally the same length,
however, the projecting portion 34 of the second jaw 30 overlaps
the projecting portion 33 of the first jaw 28 along each converging
edge by approximately the width of the barbs 58 on the second jaw
30. This overlap insures that a section of jacketed shield 12 to
which the connector 10 is attached will be pressed around each barb
46 on the first jaw 28 to insure complete electrical contact.
The jaw 30 is generally domed with a concave contact surface 54.
The jaw 30 is curved about a transverse axis, and about a
lengthwise axis to conform to the periphery of the outer jacket 14.
This configuration provides high structural strength for the
projecting portion 34 and full length engagement between the
contact surface 54 and the jacket 14 upon deflection of the
projecting portion 34 when the connector 10 is attached to a
section of a jacketed conductive shield 12. The material of the jaw
30 is resilient to maintain firm engagement with the outer jacket
14 despite deformation of the jacket which may occur due to
prolonged clamping pressure.
The barbs 46 and 58 are formed on the jaws 28 and 30 by a
multiplicity of linear spaced slits oblique to and extending
inwardly from the converging edges of the projecting portions 32
and 34. Each slit forms an angle (preferably in the range of
15.degree. to 45.degree.) with a converging edge to define a
triangular barb 46 or 58. Each barb is curved to protrude from the
contact surface of the projecting portion 32 or 34 with the point
of the barb directed away from the smaller end 42 or 56 of the
projecting portion. Jaws formed with barbs of this type have been
found to have surprisingly high resistance to fracture starting at
the slits forming the barbs upon application of high clamping
forces, apparently due to a favorable orientation of the slit ends
with respect to the bending forces in the jaws. Additionally, the
barbs along the converging edges on each jaw are spaced with
respect to the longitudinal axis of the projecting portion 32 or 34
so that barbs will not be positioned opposite each other on a jaw
which would substantially reduce the cross sectional area and
strength of the projecting portion. The barbs 28 or 30 are
preferably formed in spaced relationship along corresponding edges
of the projecting portions 32 and 34 to position the barbs on each
jaw generally in the interstice between the barbs on the opposing
jaw. This configuration aids in pressing the shield 12 about the
barbs 46 on the first jaw 28, and insures that slight misalignment
of the jaws 28 and 30 will not result in interference between
opposing barbs 46 and 58.
The conductor 18 is illustrated as a braided stranded cable,
however, the conductor may also comprise a solid or stranded
circular wire attached via a suitable terminal lug to the connector
10. The conductor 18 or terminal lug is positioned over the bolt 36
between the base portion 40 and 50 of the jaws 28 and 30. The
conductor 18 or lug should have generally the same compressed
thickness as the thickness of the jacketed shield section to which
the connector is to be attached to insure proper deflection of the
jaws upon tightening of the nut 38.
Although this invention is subject to considerable variation
without departure from the spirit thereof, it is believed that the
following specific example will facilitate understanding: The jaws
28 and 30 are formed of tin plated 1/16 inch thick copper alloy No.
260, one-half hard with the projecting portion 32 of the first jaw
28 being approximately 3/8 inch wide adjacent the base portion 40
and tapered over its 1 inch length to an end 42 with a 1/16 inch
radius. The projecting portion 34 of the second jaw 30 is slightly
wider, being approximately 1/2 inch wide adjacent the base portion
48 and tapered over its 1 inch length to a 1/4 inch wide end 30.
Each barb 46 or 58 on the jaws 28 or 30 is formed by making a 0.2
inch long slit oriented at approximately 30.degree. to the edge of
the jaw. Each jaw is curved with a 3 inch radius about a transverse
axis, and the second jaw 30 is curved about a longitudinal axis
with a 5/8 inch radius to form a concave contact surface 54.
Connectors of this construction securely connected between a
jacketed conductive shield section of a communication cable and a
conductor 18 of braided stranded copper cable of 6 gauge equivalent
have consistently met the portion of Automatic Electric Company
Requirement No. AE 8363 for grounding jumper clip assemblies
calling for 1200 ampere current flow for 10 seconds with no more
than a 5 milliohm increase in contact resistance.
* * * * *