Strain-relief electrical cable connector

• US 4,486,065 A
• Filed: 07/05/1983
• Issued: 12/04/1984
• Est. Priority Date: 04/27/1981
• Status: Expired due to Fees

• Current Assignee: Wittes, James M.
• Original Assignee: Wittes, James M.
• Inventors: Wittes, James M.
• Primary Examiner(s): DESMOND, EUGENE
• Application Number:
  US06/510,919
• Time in Patent Office: 518 Days
• Field of Search: 339/103 B, 339/105, 174/153 G, 248/56
• US Class Current: 439/450
• CPC Class Codes: H01R 13/5812 the cable clamping being achieved by mounting the separate part on the housing of the coupling device

Abstract

The connector or bushing fits into a "knock-out" hole in the wall of a junction box or the like in order to protect the cable or wires from contact with the box and to provide "strain relief", that is, to hold the cable or wire securely to prevent its conductors from being pulled loose from the electrical terminals to which they are connected. The connector has a first body member or "yoke" and a second body member or "wedge", both of which are formed in a single molding operation and are attached to one another temporarily. The yoke is fitted into the knock-out hole but only partially fills the hole. The cable is inserted through a hole in the yoke. The wedge slides in slots in the yoke and is shaped and positioned so that pressure applied to it by means of a screwdriver will cause it to break loose from the yoke, slide in the slots, and become wedged between the cable and one edge of the hole. This structure serves the dual function of holding the connector solidly in place in the wall of the box, while also providing strain relief for the cable. The connector is relatively small and inexpensive to make, and it is relatively easy to use. It can be removed and re-used, if desired. The assembly of the parts of the connector, the clamping of the cable, and the seating of the connector in the hole all are completed with a single stroke of a screwdriver, without moving the cable longitudinally.

Claims

1. A strain-relief connector for an electrical conductor, said connector comprising a first body member shaped to fit into and engage with the edge of a hole in a wall and with said conductor, a second body member shaped at one side to engage said conductor and at a second side opposite said one side, to engage said edge of said hole, said second body member being shaped to be wedged into a location substantially in the plane of said edge of said hole between said conductor and said edge of said hole, with said first body member mounted in said hole in strain-relieving engagement with said wall, in order to hold said connector and said conductor in place.

2. A connector as in claim 1 in which said second body member being adapted to move into contact with said conductor and pivot in order to move into said hole.

3. A connector as in claim 1 in which said first body member has a recess opposite said second side of said second body member when said first and second body members are assembled together, and first and second body members being dimensioned so as to compress a portion of said conductor into said recess to hold said conductor securely in place.

4. A connector as in claim 1 in which said first body member having an axially-extending central recess adapted to receive said conductor and forming two arms, the outside of said first body member having at least one groove for receiving said edge of said hole, said first body member being made of a flexible resilient material so that said arms can be depressed to allow said first body member to be fitted into said hole.

11. A connector as in claim 1 in which said second body member has a cavity shaped to receive a tool for pressing said second body member to wedge it into said location.

25. A connector as in claim 4 including a projection extending from said first body member at a point relatively remote from the ends of said arms and shaped so as to fit over the edge of a hole into which said connector is to be fitted and having a surface to engage said edge and allow the use of leverage to assist in forcing said connector into said hole.

26. A connector as in claim 4 in which said second body member is pivotably attached between said arms, said second body member being flexible in a direction between said two arms so as to facilitate depressing said arms towards one another to reduce the lateral dimension of said connection and allow said first body member to be fitted into said hole.

5. A strain-relief connector for an electrical conductor, said connector comprising a first body member shaped to fit into and engage with the edge of a hole in a wall and with said conductor, a second body member shaped at one side to engage said conductor, and at a second side opposite said one side, to engage said edge of said hole, said second body member being shaped to be wedged into a location between said conductor and said edge of said hole, with said first body member mounted in said hole, in order to hold said connector and said conductor in place, said first body having an axially-extending central recess adapted to receive said conductor and forming two arms, the outside of said first body member having at least one groove for receiving said edge of said hole, said first body member being made of a flexible resilient material so that said arms can be depressed to allow said first body member to be fitted into said hole, said first body member having guide means for receiving side edges of said second body member, said guide means comprising a pair of grooves in opposite side-walls of said arms, said second body member being wider adjacent said opposite side than adjacent said one side so that said second body member spreads said arms of said first body member apart when inserted into said grooves and holds said first body member in said hole.

12. A connector as in claim 5 in which said second body member has a generally planar surface and a transverse projection adjacent said one side, the end of said projection farthest from said planar surface being farther from said other side of said second body member than said one side is, whereby said second body member tilts towards said hole when said end of said projection contacts said conductor.

27. A connector as in claim 12 in which said transverse projection is slotted so as to make said connector flexible to facilitate its insertion into said hole.

28. A connector as in claim 5 in which the side edges of said second body member and inner side walls of said grooves are bevelled so as to provide increased resistance to motion of said second body member out of said hole when said side edges are seated in said grooves.

29. A connector as in claim 28 in which the bevelled surfaces provide decreased resistance to motion of said second body member into said hole.

6. A strain-relief connector for an electrical conductor, said connector comprising a first body member shaped to fit into and engage with the edge of a hole in a wall and with said conductor, a second body member shaped at one side to engage said conductor, and at a second side opposite said one side, to engage said edge of said hole, said second body member being shaped to be wedged into a location between said conductor and said edge of said hole, with said first body member mounted in said hole, in order to hold said connector and said conductor in place, said second body member being adapted to move into contact with said conductor and pivot in order to move into said hole, said first body having an axially-extending central recess adapted to receive said conductor and giving said first body member the shape of a yoke with arms, the outside of said first body member having at least one groove for receiving said edge of said hole, and including guide means comprising a pair of grooves in opposite internal side-walls of said arms, said grooves being shaped to receive opposite edges of said second body member and guide it into contact with said conductor as said one side and allow said second body member to pivot about said one side to tilt and move said second side into said hole.

7. A connector as in claim 6 in which said second body member has the general shape of a rectangular plate with said opposite side being curved to correspond to the curvature of said hole, and including ribs extending from the opposed remaining sides of said second body member, said ribs being only slightly narrower than said grooves adjacent said one side, and being substantially narrower adjacent said other side in order to permit limited tilting of said second body member.

8. A connector as in claim 6 including attachment means for pivotably attaching said second body member to said first body member so that said second body member is pivotable on said first body member for movement into said grooves.

9. A connector as in claim 8 in which said first and second body members and said attachment means comprise one integral molded plastic structure.

10. A connector as in claim 8 in which said attachment means includes a transverse projection adjacent said one side of said second body member, a pair of projections extending axially outwardly from said first body member, said transverse projection being attached by said attachment means to said further projections adjacent the outermost edges thereof.

13. A strain relief connector for an electrical conductor, said connector comprising, in combination, a first body member of generally semi-cylindrical shape, said first body comprising a little more than half of a cylinder, said body member having an external groove in at least a part of its outside surface, said external groove being adapted to receive the edge of a hole in a wall, a central axial recess in said first body member, transverse grooves in the side walls of said axial recess, a generally planar second body member with one edge for contacting said conductor and an opposite edge for engaging said edge of said hole, said second body member being adapted to slide in said grooves into engagement with a conductor when said conductor extends axially through the opening formed by said axial recess and said first body member is in strain-relieving engagement with said wall, and being dimensioned to make an interference fit between said conductor and said edge of said hole.

14. A connector as in claim 13 in which said second body member has a cavity for receiving the tip of a screwdriver for the application of force to said second member to effect said interference fit.

15. A connector as in claim 13 including a transverse recess extending from said axial recess, said transverse recess being opposite said one edge of said second body member so as to receive a portion of said conductor which is deformed by the pressure of said one edge of said second body member when making said interference fit.

16. A connector as in claim 13 in which said axial recess is generally rectangular in shape and forms two relatively narrow arms which can be depressed inwardly by side-ways-directed pressure from outside said connector to allow said connector to fit into said hole, said arms being resilient so as to return to a position in which said edge of said wall forming said hole fits into said external groove.

17. A connector as in claim 13 in which said external groove is formed by three separate pairs of projections, two at opposed sides of said first body member, and one pair between the other pair.

18. A connector as in claim 13 in which the width of said second body member increases gradually from adjacent said one edge to adjacent said opposite edge so as to spread said sides of said recess apart as said second member is being moved into engagement with said conductor, thus pressing and holding said first body member against said edge of said hole.

19. A strain-relief connector for an elongated insulated electrical conductor, said connector comprising a first body member shaped to fit into and engage with the edge of a hole in a wall and with said conductor, a second body member shaped at one side to engage said conductor, and at a second side opposite said one side, to engage said edge of said hole, guide means on said first body member for engaging said second body member adjacent said one side to hold said first and second members against relative movement in the longitudinal direction of said conductor but allowing said second body member to pivot about said one side and tilt so as to fit said other side under the edge of said hole with said one side contacting said conductor.

20. A device as in claim 19 in which said second body member has a pivot edge spaced from said one side in the longitudinal direction of said conductor, the distance of said pivot edge from said other side being greater than the distance of said one side from said other side so that said pivot edge contacts said conductor before said one side and tilts the second body member towards and into said hole.

21. A method of providing a strain-relief mounting for electrical cable, said method comprising the steps of providing a connector having a first body member having a conductor passageway and being adapted to fit into a hole in an electrical cabinet wall and fill a substantial portion of said hole, and a second body member shaped to mate with said first body member and to be wedged between said conductor and the edge of said hole to hold the connector and cable in said hole, mounting said first body member in strain-relieving position in said hole, inserting said cable through said passageway, and, by the application of a wedging force in a direction transverse to the longitudinal direction of said conductor and towards the edge of said hole, wedging said second body member between said conductor and said edge after so mounting said first body member.

24. A method as in claim 21 in which said wedging force is applied solely by the application of a longitudinal force to an elongated tool engaged with said second body member.

22. A method of providing a strain-relief mounting for electrical cable, said method comprising the steps of providing a connector having a first body member having a conductor passageway and being adapted to fit into a hole in an electrical cabinet wall and fill a substantial portion of said hole, and a second body member shaped to mate with said first body member and to be wedged between said conductor and the edge of said hole to hold the connector and cable in said hole, mounting said first body member in said hole, inserting said cable through said passageway, and wedging said second body member between said conductor and said edge after so mounting said first body, said second body member being pivoted to said first body member by means of frangible pivot means, including the step of pivoting said second body member about said pivot means and breaking said pivot means during said wedging step.

23. A method of providing a strain-relief mounting for electrical cable, said method comprising the steps of providing a connector having a first body member having a conductor passageway and being adapted to fit into a hole in an electrical cabinet wall and fill a substantial portion of said hole, and a second body member shaped to mate with said first body member and to be wedged between said conductor and the edge of said hole to hold the connector and cable in said hole, mounting said first body member in said hole, inserting said cable through said passageway, and wedging said second body member between said conductor and said edge after so mounting said first body member, said second body member being pivoted to said first body member by means of frangible pivot means, including the step of first breaking said pivot means, then inserting said cable in said passageway, and then mounting said first body member in said hole and inserting said cable through said hole, and then performing said wedging step.