US3086194A

US3086194A - Terminal assembly

Info

Publication number: US3086194A
Application number: US55296A
Authority: US
Inventors: Thomas C Price
Original assignee: Burndy Corp
Current assignee: FCI USA LLC
Priority date: 1960-09-12
Filing date: 1960-09-12
Publication date: 1963-04-16
Anticipated expiration: 1980-04-16

Description

April 16, 1963 T. c. PRICE 3,086,194

TERMINAL ASSEMBLY Filed Sept. 12, 1960 INVENTOR. 2 THOMAS (1. PR E AG ENT United States Patent 3,086,194 TERMINAL ASSEMBLY Thomas C. Price, Monroe, Conn., assignor to Burndy Corporation, a corporation of New York Filed Sept. 12, 1960, Ser. No. 55,296 1 Claim. (Cl. 339-272) This invention relates to terminals for conductors; and more particularly to pressure bars for attachment to setscrews for lug type terminals.

Lug type terminals have long been used in the electrical arts. They consist essentially of a socket, or similar means to receive a conductor, and a lug, tongue, spade or similar projection for attachment of the terminal to the article to which the conductor is to be connected. The lug may have a hole therethrough to receive a bolt, so that the terminal may be bolted to the article. The conductor may be secured in the terminal socket by various means, such as a setscrew, crimping, soldering or welding. The function of the setscrew is to force the conductor into good mechanical and electrical contact with the inner wall of the socket opposite the setscrew.

It is customary in the art to provide an intermediate member to transmit the force of the setscrew to the conductor. This intermediate member, or pressure bar, is commonly captured by the setscrew and may be designed to rotate relative to the setscrew. This should permit the pressure bar to remain stationary relative to the surface of the conductor and thereby not score, dig into, or otherwise damage the conductor surface; while permitting the setscrew to rotate relative to the pressure bar so that it may be screwed into the connector housing to apply pressure to the conductor. The pressure bar may also be made of resilient material which may be deformed under pressure; this tends to maintain a uniform pressure on the conductor, even though the relative dimensions of the conductor and terminal may have changed under continuous load.

.The prior art devices generally suffer from several disadvantages. The pressure bar is usually staked or permanently deformed and captured to the set screw, requiring a separate machine operation for this purpose. If the pressure bar is larger than the setscrew hole, this operation must be performed after the setscrew has been inserted in the connector. Often, the pressure bar does turn with the setscrew, damaging the surface of the conductor.

An object of this invention, therefore, is to provide a pressure bar which may be easily attached to the setscrew before the setscrew has been assembled into the terminal.

Another object of this invention is -to provide a pressure bar wherein the pressure bar setscrew interface may be lubricated to ensure free relative motion therebetween.

Yet another object is to provide a resilient pressure bar which may be deformed under load to provide a constant pressure on the conductor.

A further object is to provide a pressure bar which may be cheaply fabricated of sheet metal.

These and other objects and features of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a lug terminal, setscrew and pressure bar embodying this invention; and

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FIG. 2 is a cross section taken through the pressure bar of FIG. 1 along line IIII, and including a portion of the setscrew assembled thereto.

FIG. 1 illustrates a terminal assembly including a terminal body 1 having a conductor receiving socket 2, lug 3 and a threaded hole 4 in the socket wall providing access to the socket. A setscrew 5 is disposed in hole 4 and a conductor (not shown) may be disposed in socket 2. Setscrew 5 is provided with annular groove 6 adjacent its force applying end. A sheet metal, cup shaped, pressure bar 7 having a plurality of resilient fingers 8 may be snapped onto the end of the screw, an inward going bend 9 in each finger 8 engaging the groove 6.

As may also be seen in FIG. 2, the base of the bar 7 may be indented to provide a plurality of radial projections 10. Projections 10 are adapted to engage the surface of the conductor, and prevent the bar 7 from rotating on the surface of the conductor. The projections 10 are also adapted to resiliently deform under load; thereby maintaining a constant pressure on the conductor even though the conductor may tend to deform under load.

Being cup shaped, the bar 7 is especially adapted to receive therein a lubricant, such as a graphite powder, and thereby maintain a lubricated interface between the bar 7 and the setscrew 5 having minimum friction therebetween. The bar 7, being held to the screw 5 solely by its resilient fingers 8, may be easily removed and replaced on the screw 5 for lubrication purposes. This arrangement ensures that the bar 7 will not rotate with respect to the conductor surface, but will rotate with respect to the setscrew 5, as the screw is tightened against the conductor.

The pressure bar 7 may easily and cheaply be formed out of sheet metal stock. The annular groove 6 on the end of the setscrew 5 may be machined below the base of the thread, thereby permitting the use of a pressure bar smaller in diameter than the bolt; which may be snapped onto the setscrew before it is assembled into the connector; the subassembly of screw 5 and bar 7 then being screwed into hole 4.

The invention has thus been described but it is desired to be understood that it is not confined to the particular forms or usages shown and described. The same being merely illustrative, and that the invention may be carried out in other ways without departing from the spirit of the invention, and therefore, the right is broadly claimed to employ all equivalent instrumentalities coming within the scope of the appendent claims, and by means of which objects of this invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and described are only some of the many that can be employed to obtain these objects and accomplish these results.

I claim:

A terminal assembly for a conductor comprising: a body having a conductor receiving socket therein; a threaded hole included in the wall of said body giving access to said socket; a setscrew disposed in said threaded hole and adapted to project into said socket, an end portion on said screw having a surface for applying pressure to an abutting surface, an annular groove on said screw adjacent said end portion; a cup shaped intermediate member adapted to transmit pressure from said end portion to the surface of an inserted conductor; said cup enclosing said end portion and having a plurality of resilient 3 fingers adapted to engage said groove; said cup including a plurality of resilient projections adapted to engage the surface of the inserted conductor and thereby fix said cup to the conductor surface; said cup being free to rotate with respect to said setscrew.

References Cited in the file of this patent UNITED STATES PATENTS 1,275,961 Maynard Aug. 13, 1918 Great Britain Feb. 23, 1901