Clamping mechanism for mounting circuit condition monitoring devices on cables of various diameters

• US 5,990,674 A
• Filed: 09/29/1997
• Issued: 11/23/1999
• Est. Priority Date: 07/08/1996
• Status: Expired due to Fees

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: E.O. Schweitzer Manufacturing Compay, LLC
• Inventors: Schweitzer, Edmund O. Jr.
• Primary Examiner(s): Do, Diep N.
• Application Number:
  US08/940,069
• Time in Patent Office: 785 Days
• Field of Search: 324/127, 324/133, 324/541, 324/544, 324/551, 340/664, 336/176
• US Class Current: 324/127
• CPC Class Codes: G01R 1/22 Tong testers acting as secondary windings of current transformers
• CPC Class Codes: G01R 15/14 Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks

Abstract

A clamping mechanism for mounting a circuit condition monitoring device to electrical cables of various diameters includes a core member comprising a plurality of laminations arranged in a generally rectangular configuration. A spring spanning the core member is anchored at one end to the core at a point near the housing of the monitoring device and at the other end is attached to a bridging member affixed at the opposite end of the core near the housing. This allows the spring to expand less as it transverses the bridge in order to accommodate different power cable diameters.

Claims

1. A clamping mechanism for mounting a circuit condition monitoring device on electrical cables having a predetermined range of diameters, comprising:

a housing for said monitoring device having a cable engaging surface;

a core member extending from said housing and adapted to encircle a cable, said core member having a first portion generally on one side of said cable and a second portion generally on the other side of said cable;

a bridge member having one end attached to said first portion of said core member at a first location, and its other end attached to said first portion of said core member at a second location between said first location and said housing;

biasing means attached at one end to said bridge member and attached at its other end to said second portion of said core member for biasing said cable into engagement with said cable engaging surface, said biasing means being attached to said bridge member by a sliding attachment allowing said one end of said biasing means to slide generally between said first location and said second location on said first portion of said core member;

said second portion of said core member including a gap between said attached biasing means and said housing for passing said cable into said core member between said biasing means and said cable engaging surface; and

said one end of said biasing means sliding on said bridge member to accommodate said predetermined range of cable diameters.

2. A clamping mechanism as defined in claim 1 wherein said biasing means comprise a helical spring.

3. A clamping mechanism as defined in claim 1 wherein said core member comprises a plurality of parallel metallic strips.

4. A clamping mechanism as defined in claim 1 wherein said cable engaging surface comprises a channel axially aligned with said cable.

5. A clamping mechanism as defined in claim 1 wherein said bridge member provides a sliding engagement with said attached one end of said biasing means whereby said one end ramps on said bridge member from a position closer to said attached other end of said biasing means to a position further from said attached other end of said biasing means as it slides from said second location to said first location with cables of increasing diameter.

6. A clamping mechanism as defined in claim 5 wherein said bridge member comprises a rigid wire.

7. A clamping mechanism as defined in claim 6 wherein said biasing means comprise a helical spring.

8. A clamping mechanism as defined in claim 1 wherein said core member includes first, second and third contiguous segments, said first segment extending generally perpendicular to and on one side of said cable engaging surface on one side of said cable to an end, said second segment extending generally perpendicular to and on the other side of said cable engaging surface on the other side of said cable to an end, said third segment extending between said ends of said first and second segments, said bridge member being attached to said first segment and said other end of said biasing means being connected to said second segment.

9. A clamping mechanism as defined in claim 8 wherein said core member includes a fourth segment extending through said housing between the originating ends of said first and second segments, and said gap is located in said fourth segment.

10. A clamping mechanism as defined in claim 9 including a magnetic winding on said fourth segment within said housing.

11. A clamping mechanism as defined in claims 1 or 9 wherein said biasing means bias said gap closed.

12. A clamping mechanism as defined in claim 9 wherein said core member comprises a plurality of parallel metallic strips.

13. A clamping mechanism as defined in claim 9 wherein said bridging member is attached at said first end to said first core segment and at its other end to said fourth core segment.

14. A clamping mechanism as defined in claim 13 wherein said bridging member comprises a rigid wire extending between said first and second locations.

15. A clamping mechanism as defined in claim 14 wherein said one end of said biasing means slidably engages said wire.

16. A clamping mechanism for mounting a circuit condition monitoring device on electrical cables having a predetermined range of diameters, comprising:

a housing having a cable engaging surface;

a core member extending from said housing and adapted to encircle a cable, said core member including a first portion extending generally perpendicular to and on one side of said cable engaging surface, said first portion being integral with a second portion generally parallel to said cable engaging surface, said second porting being integral with a third portion generally parallel to said first portion and on the other side of said cable engaging surface, said third portion having an end movable relative to said housing providing a gap for passing said cable through to a position engaging said cable engaging surface;

a bridge member having a first end anchored at a first location on said first core portion, and a second end anchored at a second location between said first location and said housing; and

means for biasing said cable into engagement with said cable engaging surface, said biasing means being slidably connected at one end to said bridge member and slidable thereon generally between said first and second locations to accommodate said predetermined range of cable diameters, the other end of said biasing means being connected to said movable end of said third core portion to bias said gap closed.

17. A clamping mechanism as defined in claim 16 wherein said biasing means comprise a helical spring.

18. A clamping mechanism as defined in claim 16 wherein said core member comprises a plurality of parallel metallic strips.

19. A clamping mechanism as defined in claim 16 wherein said cable engaging surface comprises a channel axially aligned with said cable.

20. A clamping mechanism as defined in claim 16 wherein said bridge member provides a sliding engagement with said attached one end of said biasing means whereby said one end ramps on said bridge member from a position closer to said attached other end of said biasing means to a position further from said attached other end of said biasing means as it slides from said second location to said first location with cables of increasing diameter.

21. A clamping mechanism as defined in claim 16 wherein said bridge member comprises a rigid wire.

22. A clamping mechanism as defined in claim 21 wherein said biasing means comprise a helical spring.