AU698893B2

AU698893B2 - Cable earthing clamp

Info

Publication number: AU698893B2
Application number: AU28442/95A
Authority: AU
Inventors: Roger Barker; Arthur Nobbs
Original assignee: Alcatel Australia Ltd
Current assignee: Nokia Services Ltd
Priority date: 1994-08-18
Filing date: 1995-08-08
Publication date: 1998-11-12
Anticipated expiration: 2015-08-08
Also published as: AU2844295A

Description

P/00/01i1 28/5/91 Regulation 3.2 Patents-Act-19.90

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT .5

S

9 4* 9

S

Invention Title:

S*

S 4 itCABLE EARTHING

CLAMP

The following statement is a full description of this invention, including the best method of performing it known to us:- 5*

V

This invention relates to a cable earthling clamp for earthing the shielding element of a cable, particularly thought not exclusively, a telecommunication cable.

When conductors of such a. cable are connected to circuit elements supported within a housing of electrically conductive material, in order to prevent the radiation of VH frequencies which may be present in signals carried by the conductors, as well as shielding the conductors from external electric/magnetic fields, it is necessary to electrically connect the shielding element of the cable, which may be either braid or foil to the housing. The housing may or may not be connected to earth.

Cable earth clamps are known. One such example comprises a simple saddle-shaped clamp which is bolted to a chassis to clamp an exposed section of shield element to the conductive housing.

A disadvantage this known earthing clamp is that any movement of the cable tends to cause the clamping effect to relax and the electrical contact between the shield and the housing becomes unreliable.

An object of the present invention is to provide a cable earthing clamp which is to mechanically simple and provides a constant resilient pressure to ensure a reliable electrical contact between a section of the shielding element and the conductive housing.

According to the invention, there is provided a cable clamp arrangement for electrically connecting a shielding element of an electric cable to a conductive membier, suiu clamip ui rui em n co p s ng ap c~ inn -i eI aseiI e"4~ I II U'I' two side walls joined by an end wall which end wall is at least partly electrically conductive for contacting a section of said shielding element of said cable when clamped in said base element, and which end wall is provided wi fixing means for fixing said base element to said conductive member to provide electrical contact between the electrically conductive part of said end wall and said conductive member, and a mateable channel-like clip element having two side walls joined by an end wall which end wall is provided a spring means extending therefrom and bounded by the side walls of the clip element, wherein the side walls of the base element and the clip element include co-operating releasable latching means arrangement to latch in at least one position said clip element to said base element for forming an open ended

I

4 3 tube of a first predetermined diameter about said section of said shielding element which is resiliently urged against the electrically conductive part of said base elements end wall by said spring means.

In order that the invention may be readily carried into effect, an embodiment thereof will now be described in relation to the accompanying drawings, in which: Figure 1 is a top view of the base element of the cable earthing clamp of the present invention.

9 .5 9B B. 9 a

B

Figure 2 is a side view of the base element of Figure 1.

Figure 3 is an end view of the base element of Figures 1 2.

Figure 4 is a bottom view of the clip element of the cable earthing clamp of the present invention.

Figure 5 is a side view of the clip element of Figure 4.

Figure 6 is a cut-away side view of the clip element of Figures 4 and illustrating cable sheath hooks and the clamping spring.

Figure 7 is an end view of the clip element shown in Figures 4 to 6, Figure 8 is a side view of an assembly of the base element and the clip element.

Figure 9 is a cut-away side view of an assembled cable earthing clamp illustrating its operation.

Figure 10 is an end view of an assembled cable earthing clamp clamping a relatively small diameter cable.

Figure 11 is an end view of an assembled cable earthing clamp clamping a relatively large diameter cable.

The cable earthing clamp of the present invention comprises two separate elements, viz a base element A and a clip element B. Referring to Figures 1 3, the base element A comprises a channel-like member made of 0.3 mm thick stainless steel having two side walls 1 and 2 joined by a bottom wall 3; the dimensions of the channel-like member are approximately 45 mm long x 10.5 mm wide x 8 mm high.

Each side wall 1 and 2 is provided with six co-linear outwardly extending protrusions 4. Bottom wall 3 is provided with two spaced through-holes 5 and 6.

Referring to Figures 4 6, the clip element B comprises a channel-like member

II

4 made of 0.3 mm thick stainless steel having two side walls 7 and 8 joined by a top wall 9; the dimensions of this channel-like member are approximately 45 mm long x 12 mm wide x 9 mm high. Each side wall 7 and 8 is provided with two rows of two co-linear slots 10 and 11. Further, each side wall 7 and 8 is provided with a handle 12. A cantilever spring 13 extends longitudinally from the inner surface of top wall 9 and is bounded by side walls 7 and The dimensions of spring 13 are approximately 25 mm long and 8 mm wide. Extending from top wall 9 are two flat cable-hook members 13 and 14.

In use, referring to Figures 9 11, base element A is bolted, via through-holes and 6, to a conductive support (not shown) such as, for example, a chassis or housing. A section of the shielding element 15 of a cable 16, whose conductors are to be connected within the chassis or housing, is exposed and laid in base element A.

Clip element B is then mated with base element A. The leading edge of side walls 7 and 8 of clip element B striking protrusions 4 of base element A and causing side walls 7 and 8 to resiliently spread outwardly until protrusions 4 enter and rest in slots I 11. In this fixed position cantilever spring 13 resiliently urges the exposed section of shield element 15 against the bottom wall 3 of base element A to establish an electrical contact therebetween. Cable hook members 13 and 14 resiliently press against the cable's outer protection sheath thereby preventing lateral movement of the cable.

As illustrated in Figure 10, a relatively small diameter cable can be I accommodated by utilizing slots 12 whereby cantilever spring 13 and cable hooks 13 and 14 are positioned closer to bottom wall 3 of base when protrusions 4 enter and nest in slots 12.

It will be understood that clip element B and its associated cantilever spring i and cable hooks may be made of a suitable plastics material. Base element A could also be partly made from plastics material. i' An assembled cable earthing clamp as shown in Figures 9 11 can be disassembled by inserting a tool, such as a screw driven, into handle 12 and levering, The present invention also envisages a insulation penetrating means incorporated in the base element A whereby it would not be necessary to remove the

T

I outer insulating sheath from the cable section laid in the base element. The insulation penetrating means may be in the form of an array of lances protruding from the bottom wall of the base element and arranged such that they penetrate the outer sheath to a depth sufficient to contact the shielding element of the cable when the clip element B is latched to the base element A.

While the present invention has been described with regard to many particulars, it is understood that equivalents may be readily substituted without departing from the scope of the invention.

4 |e *44* 0* 4 4

U

eL1 S* U a *4 "ii

W*

a a i I A

A

o t

Claims

1. A cable clamp arrangement for electrically connecting a shielding element of an electric cable having a substantially circular cross-section to a conductive member, said clamp arrangement comprising a channel-like base element having two side walls joined by an end wall which end wall is at least partly electrically conductive for contacting a section of said shielding element of said cable when clamped in said base element, and which end wall is provided with fixing means for fixing said base element to said conductive member to provide electrical contact between the electrically conductive part of said end wall and said conductive member, and a mateable channel-like clip element having two side walls joined by an end wall which end wall is provided with a spring means extending therefrom and bounded by the S side walls of the clip element, wherein the side walls of the base element and the clip element include co-operating releasable latching means arrangement to latch in at Sleast one position said clip element to said base element to form an open ended tube 15 assembly of a first predetermined diameter about said section of said shielding S element which is resiliently urged against the electrically conductive part of said base S elements end wall by said spring means, said open ended tube assembly and said section of shielding element therein being substantially collinear.

2. An arrangement as claimed in claim 1, wherein said releasable latching means comprise at least a first slot arrangement in a side wall of one channel-like element S ond at least one co-operating first protrusion arrangement on an adjoining side wall o* of the other channel-like element so arranged that when said base element and clip element are mated, the at least one first protrusion arrangement slidably enters and nests within said at least one first slot arrangement to latch said clip element in a first predetermined position.

3. An arrangement as claimed in claim 2, wherein said first slot arrangement comprises at least two co-linear spaced slots and said first protrusion arrangement comprises at least two co-linear spaced protrusions.

4. An arrangement as claimed in claim 2, wherein said releasable latching means includes a second slot arrangement and a co-operating second protrusion arrangement for latching said clip element in a second predetermined position to form said open ended tube assembly of a second predetermined diameter which is less Sn the first predetermined diameter.

J -li r ii C ii h i 'PT' C r i L i -r~r~n~ 7 An arrangement as claimed in any one of claims 1 to 4, wherein said clip element includes means for preventing lateral movement of said section of shielding element.

6. An arrangement as claimed in claim 5, wherein said means for preventing lateral movement comprises at least one protrusion extending from the end wall of said clip element and bounded by the side walls thereof, said one protrusion being arranged to bear against said electric cable's outer sheathing when said clip element and said base element are latched together.

7. An arrangement as claimed in any one of the preceding claims, wherein said clip element and said base element are made of stainless steel.

8. An arrangement as claimed in any one of claims 1 to 6, wherein said clip element and/or the side walls of said base element are made of plastic material.

9. An arrangement as claimed in any one of the preceding claims, wherein at .1 5 least one said side wall of said clip element includes a further slot for co-operating with a tool for dis-assembling an assembled clamp arrangement.

10. A cable clamp arrangement substantially as herein described will referent to i Figures 1 11 of the accompanying drawings. DATED THIS ELEVENTH DAY OF JULY 1995 ALCATEL AUSTRALIA LIMITED 000 005 363) 0: ii i i i I IL r c- ABSTRACT A cable earthing clamp for electrically connecting a section of a cable shielding element (15) to a chassis. The clamp comprises a channel-like base member and a mateable channel-like clip member The base member is attached to the chassis and a section of the cables shielding element is laid in the base member and the clip member mated with the base member, whereupon a cantilever spring (13) that extends from a wall of the clip member urges the section of the shielded element against a wall of the base member to establish a reliable electrical contact between the shield element and the chassis. (Figure 9) .4.4 #4 4. 0 r 0 .4 *44 *4 .4 *4 4 44 3t'" rr t