US2253550A - Conductor clamp - Google Patents

Description

Aug. 26, 1941. BQHN 2,253,550

CONDUCTOR CLAMP Filed Aug. 26, 1938 INVENTOR.

Dom/.0 I. BOHN.

BY WW A ORNEY.

Patented Aug.26,'1941 a 2,253,550

UNITED STATES PATENT oFFlce CONDUCTOR CLAMP Donald 1. Bohn, South Hiils. Pa., assignor a. Aluminum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania Application August 2c, 1938, SerialNo. 226,951 4 Claims. (01. 24-135) This invention relates to clamps for joining been exerted in turning down the bolts. so that electrical conductors. The invention relates parbowing or the plates similar to that occurringin ticularly to clamps for holding together porthe clamp mentioned above has occurred, or intions of electrical conductors to produce a strong sufficient pressure has been exerted, causing slipmechanical joint and good electrical oonnec- 5 ping and burninginthe'loint.

tiontherebetween. In either of the aforementioned clamps the Electrical conductors have been iestened toproper degree of force to be applied in turning gether by several diflerent means. For examdown the bolts to obtain the correct pressure ple, it has been common practice to join bus desired uponthe conductors is not readily deterbars by drilling holes through overlapping end minable since it depends upon the estimation and portions thereo! and fastening them with bolts judgment of the individuals applying the clamp, passing through the holes. This means has been which are variable factors. Another difficulty round impractical in many instances, as, for on inherent in such clamps is their tendency to ample, where a large number of bus bars are to loosen upon subjection to temperature changes, be joined together to form a single joint. in due to the difference in the cocfflcients of expanthis case all 01 the bars must either be predrilled sion of the conductors and the clamps.

and all 0! the holes lined up before the bolts One object of the present invention is to procan be entered, or the holes must be drilled vide an improved clamp for joining electrical through. a great thickness or metalaiter the conductors which in use requires no drilling 01' bars have been overlapped. When it is consid- .20 the conductors. Another object of the invention cred thatelectrical conductors are oiten conis to provide such a conductor clamp capable nested in inaccessible and elevated places, it is of maintaining effe v ing P s v apparent that considerable inconvenience and relatively wide temperature changes. Another delay are occasioned in joining them by this object is to provide a conductor clamp capable means. 4 l ot exerting an increased, predetermined pres- Another known device tor fastening together sure concentrated inwardly oi the longitudinal electrical conductors comprises two metal plates d es 0! h conduc ors clamped. The inveneach having auniplanar working race. The plates 11011 h Illrther Object h p i n of a are placed one upon each side or the overlapped conductor clamp having telltale means by which portions of the conductors and pulled together it can be readily ascertained when the desired by bolts passing through lugs on the plates exp det rmi ed p ssu e h s n a pl e A tending beyond the edges 0! the overlapped co'nother object is to provide a clamp which comductors. This type of clamp avoids the necessity pris oppo it ly-di p s d P hill/1518 telltale for drilling the conductors but has the inherent means attached'thereto and raised gripping surdisadvantage of causing permanent detormatlon laces cooperating with the telltale means to con 01 the conductors at their edges, with resultant centrate all or the pressure exerted by the clamp relief or the pressure. as a result of bowing of at areas intermediate the longitudinal edges oi. the clamping plates between the bolts when the conductors. the clamp is applied. This bowing also results The invention comprises broadly a clamp hiivin relatively low pressures upon the conductors 40 me two clamping members inthe iorm oi plates in the areas toward the center 01 the clamp due with oppfl yosed laces adapted to be boltto the arching oi the working iaces oi the plates d Otherwise drawn together around the conin these regions. The net result has been that ductors to be clamped without drilling the conthis clamp has not been entirely satisfactory. ductors, and having disposed therebetween one In order to compensate for this bowing effect, or more springs oi predetermined lull load caclamps have been developed having plates with pacity, that is, capable oi exerting a known prenormally convex working laces intended to condetermined. iorce when completely compressed. centrate the pressure intermediate the edges The springs are so arranged that as the plates where the metal cannot be as easily deformed. are drawn together the springs are compressed when these clamps are applied to the conducbetween a portion 01 the clamp and the contors, it is intended that the bolts be drawn down ductor to apply and concentrate the clamping until the working faces '01 the plates have bepressure at areas inwardly oi the longitudinal come parallel, ut it has been iound diiiicult to edges ot the latter, and that they serve. when determine when this condition existed, and the totally compressed, to indicate that sumcient result has been that either too much iorce has clamping iorce has been applied. The iuventightening of the clamp.

Fig. 2 is a view similar to Fig. 1 and shows the position 01' the parts when the clamp is in operative clamping position.

Fig. 3 lsa sectional view taken on the line IIIIII of Fig. 2.

reached,

bars;

Springs may be selected having loading characteristics such that when sensible change in the resistance of being drawn up.

2. .A clamp for fastening together a plurality oi substantially flat conductors and the like comassasso a 3 by said-washers and being disposed opposite said washers, said washers and said bosses serving as means for spacing said members from the objects clamped and for thus conflning applied clamping pressure within the areas mutually encompassed thereby, bolts reieasably connecting opposed ends of said members but spaced from said washers and said bosses, and nuts for drawing up ed to compress and flatten said washer between securing member and obiects duced noticeable by visual inspection and by manually sensible change in the resistance of the said bolts andholding said members in clamped relationship on opposite sides of objects clamped,

said nuts and boltsbeing thus adapted to compress and flatten said washers between said. washer securing member and objects clamped,

whereby-drawing up the nuts and bolts flattens the washers to produce a predetermined pressure in the clamp noticeable by visual inspection and by sensible change in the resistance of the clamp to beingdrawn up. p

3. A clamp for fastening together a plurality of substantially flat conductors and the like comprising a pair of opposedclamping members, a substantially conical spring washer secured at the center thereof to a flat innerface of one of clamp to being drawn up. I

4. A clamp for fastening together a plurality of substantially flat conductors and the like comat the centers thereof to a flat inner face of one of said members, said washers being adapted to be compressed toward and flattened against said face of said member, a like plurality of bosses'raised from the inner face of the other of said members having surfaces forming flat clamping faces, said bosses encompassing areas substantially coextensive with those encompassed by said washers and'being disposed concentrlcally of said washers. said washers and said said members, said washer being adapted to be compressed toward and flattened against said face of said member, a boss raised from the inner face of the other of said members having a sur- (7 face forming a flat clamping face, said boss encompassing an area substantially coextensive with that encompassed by said washer and disposed concentrically with said washer, said washer and said boss serving as means for spacing said members from objects clamped and for thus confining applied clamping pressure within the areas mutually encompassed thereby, and means releasabiy connecting opposed ends of said members but spaced from said washer and said boss same in clamped relationship on opposite sides of objects clamped, said means being thus adapt-' for drawing up said members and holding the holding said members in clamped relationship on opposite sides of objects clamped, said nuts and bolts being thus adapted to compress and flatten said washers between said washer ecuring members and objects clamped, whereby drawing up the nuts and bolts flattens the washers to produce a predetermined pressure in the clamp no- -ticeabie by visual inspection and by sensible change in the resistance of the clamp to being drawn up.

DONALD LBQBN.

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