US3747052A - Clamp for blade for higher rating dyna-mate caps - Google Patents

Abstract

A conductor clamp is provided capable of rapid assembly and reliable securing of a conductor to a power blade, contact or the like. Rapid assembly is achieved by forming a U-shaped conductor troth, inserting a winged contact into the U and rotating the winged contact to bring the wings into engagement with conforming slots in the uprights of the U. A screw threaded through the winged contact prevents disassembly.

Description

United States Patent 1191 Sheldon 1451 July 17, 1973 CLAMP FOR BLADE FOR HIGHER RATING 1 DYNA-MATE CAPS [75] Inventor: Luther M. Sheldon, Cranston, R.I.

[73] Assignee: General Electric Company,

Providence, R.I.

[22] Filed: June 24, 1971 [21] Appl. No.: 156,179

[52] US. Cl. .J 339/272 VC [51] Int. Cl. H01r 11/10 [58] Field of Search 339/263, 272

[56] References Cited UNITED STATES PATENTS 2,782,388 2/1957 Opalcnik et al..... 339/272 UC 2,967,290 l/l96l Zellei' 339/272 R FOREIGN PATENTS OR APPLICATIONS l,045,330 l0/ 1966 Great Britain 339/272 UC 12/1923 Germany .1 339/272 R 2/1952 Germany 339/272 UC Primary Examiner-Joseph M. McGlynn Attorney-Paul E. Rochford et al.

[57] ABSTRACT A conductor clamp is provided capable of rapid assembly and reliable securing of a conductor to a power blade, contact or the like. Rapid assembly is achieved by forming a U-shaped conductor troth, inserting a winged contact into the U and rotating the winged contact to bring the wings into engagement with conforming slots in the uprights of the U. A screw threaded through the winged contact prevents disassembly..

1 Claim, 7 Drawing Figures This invention relates to wire clamps and more particularly wire clamps formed as part of contacts or blades or the like of wiring devices.

In many wiring devices power blades or contacts of female connectors to receive power blades must be attached to power supply conductors,either single solid strand or multistrand. For higher power ratings effective clamping of some portion of a contact or blade to the conductor is needed to avoid problems of loss of effective contact due to loosening of the clamping hold on the power conductor, or due to expansion and contraction of the clamp and conductor due to the heavy power conducted in the device or to heating at the clamp due to poor contact. This latter problem is particularly troublesome in use of aluminum conductors because of the strong'tendency of aluminum metal to change its dimensions under stress and because of its tendency to build up a non-conductive surface oxide layer as a result of heating. As the layer builds up greater heating results and this leads to further oxide production. Reliable gripping of a conductor and particularly an aluminum conductor is important for this reason.

Patents which teach various forms of cable clamps to serve the purpose of connecting cables to various forms of connector and which illustrate the state of this art include the following: US. Pat. Nos. 2,958,068; 2,602,104; 3,133,781; 2,516,572; 2,780,793; 2,786,190; 2,877,443; 2,938,191; 2,164,021; and 3,041,576.

Further direct contact of the conductor with the element to receive the electric power is important as metal joints made by soldering, braizing or welding can be faulty and flaws may not be apparent. Transmissionof high power through faulty joints can cause breakdown and damage.

It is accordingly an object of the present invention to provide a low cost reliable connector suitable for use in connection with receiving relatively high power electric supply from solid or stranded conductors.

Another object is to provide a clamp effective in receiving high current flows of 30 or 50 amps from conductors into electrical blades and contacts of caps and connectors.

Still another object is to facilitate rapid reliable mounting of electrical parts to conductors.

A further object is to provide a clamp for a cable usable with copper or aluminum conductors.

Still a further object is to provide a clamp capable of quick assembly and disassembly from a cable.

Other objects and advantages of the present invention will be in part apparent and in part pointed out in the description which follows.

In one of its broader aspects the objects of the invention may be achieved by providing a clamp for removably securing a power conductor of heavy cross-section in electrical engagement with a metal connector element comprising,

a semi-rigid U-shaped element having a long closed end slot in one upright thereof and a shorter closed-end slot in the other upright thereof,

a semi-rigid cross piece for said U-shaped element,

said cross piece having oppositely extending short wings adapted to fit into the slots of'said U-shaped element on rotation of said cross piece within the hollow of the U a threaded opening in the winged portion of said cross piece,

a pressure screw in said opening,

said cross piece having a portion extending from said winged portion serving as an electrical contact to transmit electric power received from a conductor clamped between the pressure screw and the well of said U- shaped member.

In the description which follows the manner of carrying out the invention will be made clearer by reference to the accompanying drawings in which:

FIG. 1 is a perspective view of the assembled combination conductor clamp and blade contact showing an exposed end of an insulated conductor poised for entry into the clamp.

FIG. 2 is a similar view of the clamp and contact element of FIG. 1 after disassembly of the elements.

FIG. 3 is an end elevation view of the clamp portion of the device of FIG. 1.

FIG. 4 is a side elevation of one side of the clamp and contact as shown in FIG. 1.

FIG. 5 is a side elevation of the opposite side of the clamp and contact as shown in FIG. 1.

FIG. 6 is a vertical section of the clamp taken along the lines 6--6 of FIG. 4.

FIG. 7 is a top plan view of the clamp and portion of the contact as illustrated in FIG. 1.

Referring first to FIG. 1 a sheathed wire 10 having a stripped end 12 is shown in position to be inserted into the combination wire clamp and contact of this invention. The wire itself may be solid or it may be stranted, it may be copper or aluminum or other metal such as copper sheathed aluminum.

The wire clamp is made up of three pieces a semirigid U-shaped wire receiving trough 14, a semi-rigid cross member 16 having a contact formed integrally therewith, and a pressure screw 18.

The construction and operation of the clamp will be made clear by reference to the other FIGS. 2 through 7 in the description which follows.

The U element 14 is formed of a metal such as brass of a gauge sufficient to withstand deformation as the clamping pressure is developed on an inserted conductor by turning down screw 18. A semi-rigid structure results from use of strip of sufficient gauge in forming the U.

A slot is formed in each upright of the U. One slot 20 is deep and permits rotation of a winged cross piece 24 to bring the short wing 26 into engagement with the top surface defining deep slot 20.

The second slot 22 is shallower than its opposite counterpart, slot 20, but its upper edge is parallel with the upper edge of slot 20. In this way a cross member such as 16 is held generally horizontal when the U is oriented generally vertically.

A second short wing 28 extends from cross member 24 in a direction opposite to the wing 26. The wing 28 is of a dimension to enter into and be held within slot 22 In assembling the cross member into the U the cross member is first rotated to approximately the position shown in FIG. 2 relative to the U and the slots of the U. In the rotated position shown it enters the hollow of the U between the uprights thereof and comes freely into place with its wings proximate the slots.

The cross piece is then counter rotated so that wing 28 enters shallow slot 22 directly by turning and sliding in. By contrast wing 26 rotates up through the depth of the deeper slot 20 until its upper surface abuts the top surface of slot 20.

A pressure screw 18 is then screwed into the threaded hole 19 and when in position prevents the rotation of the cross piece 24 to a degree which permits its removal from the U.

The structure is unique in the simplicity and facility of the assembly of the cooperating parts where the cross member part is itself a part of a contact supplying or receiving a high level of power from another contact.

Thus the structure which results is not the equivalent of a contact in which two shallow slots are formed in a U and a narrow cross piece is slid into the slots from one external side as in this case no extending contact element such as 15 of FIG. 1 would be present as an integral part of the cross piece.

Rapid reliable facile assembly of a clamp and contact combined structure is a feature of the structure of the present invention.

Substantial pressure can be developed on a solid orstranded wire roughly in the range of No. to No. 4 wire for the same size clamp in the form shown in the FIGURES and satisfactory transfer through the contact and clamp of high electric power loads is feasible without over heating or damage to the structure or enclosure in which it is contained. The structure easily handles 60 ampere AC or DC loads at 250 volts with less than 30 rise above ambient temperature.

An important point in the construction of the present invention is that blade configurations for various locking, angled, grounding or similar assemblies can be and have been constructed using the same clamp as taught herein.

This clamp is effective in use partly because the combination of the short and long slot keeps the cross piece in its upper position so that the trough is open to receive a cable end and the pressure screw serves as a counter rotation stop for the cross piece.

What is claimed is:

1. An electrical connector for removably securing a power conductor of heavy cross-section in electrical engagement with a metal contact blade comprising,

a semi-rigid U-shaped element, said element having an open central well, having a closed end slot extending along a substantial length of one upright thereof, and having a shorter closed end slot in the other upright thereof,

a semi-rigid cross piece, said cross piece having oppositely extending short wings, said short wings having widths matching the widths of the slots of said U-shaped element and lengths approximately matching that of the thickness of the uprights of said U-shaped element,

a threaded opening generally centrally of the winged portion of said cross piece,

a pressure screw within said opening said cross piece having a portion thereof extending from said winged portion to serve as an electrical contact to transmit power received from a conductor clamped between the pressure screw and the well of the U-shaped member.

Claims (1)

1. An electrical connector for removably securing a power conductor of heavy cross-section in electrical engagement with a metal contact blade comprising, a semi-rigid U-shaped element, said element having an open central well, having a closed end slot extending along a substantial length of one upright thereof, and having a shorter closed end slot in the other upright thereof, a semi-rigid cross piece, said cross piece having oppositely extending short wings, said short wings having widths matching the widths of the slots of said U-shaped element and lengths approximately matching that of the thickness of the uprights of said U-shaped element, a threaded opening generally centrally of the winged portion of said cross piece, a pressure screw within said opening said cross piece having a portion thereof extending from said winged portion to serve as an electrical contact to transmit power received from a conductor clamped between the pressure screw and the well of the U-shaped member.

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