US 3068445 A
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1952 E. c. CROWTHER ELECTRICAL CONNECTOR Filed Sept. 21, 1959 INVENTOR. Edmond C. Crou/Zher 3,ii68,445 ELECTRICAL CONNECTOR Edmond C. Crowther, North Hampton, NH. Filed Sept. 21, 1959, Ser. No. 841,212 1 Claim. (Cl. 339-246) This invention relates to an electrical connector. More specifically, it relates to an electrical connector wherein a device of the type commonly known in the art as a bus bar is mechanically formed so that, when used in combination with other elements, it will accept lead wires or secondary conductors and removably retain same in direct contact with the material of the bus bar.
Heretofore, metallic connectors employed for electrically connecting primary conductors of current, such as bus bars, with the secondary wire conducting means have been complex in nature. Undue resistance to the passage of electrical current between the source and the end conductor is often present in such connectors. In addition, their complexities have provided inherent problems to the persons making the initial assembly, as well as those Who were called upon to utilize the connector in repair work.
It is a primary object of this invention to provide an improved electrical connector which may be partially formed from the basic conductor or bus bar. It is a further object of this invention to provide a connector which has improved electrical conductivity properties. Still another object of this invention is to provide an electrical connector which is simple in operation and economical to manufacture.
Further objects of this invention will become apparent to those skilled in the art when the specification is read in conjunction with the accompanying drawings wherein:
FIG. 1 is a perspective view of an embodiment of this invention; and
FIG. 2 is a partial sectional view taken along the longitudinal axis of the embodiment shown in FIG. 1 and illustrating the use of the connector when the secondary conducting wires accommodated in the connector are of dissimilar diameters.
Referring now to the drawings, a connector includes a base 12, a clamp 14 and a rotary threaded fastener or operator 16. The base 12 is an electrically conductive member and can be a member of substantial cross-section of the type generally known in the trade as a bus bar.
The embodiment disclosed in FIGS. 1 and 2 provides base 12 with a threaded aperture 18, which may take any suitable form, in the present instance a drawn cup which is internally threaded is provided to insure adequate thread engagement with the operator 16. Spaced apart along the longitudinal axis of the base 12 on opposite sides of aperture 18 are a pair of transverse slots 20.
Telescopically associated with threaded aperture 18 is the rotary threaded fastener or screw 16. Screw 16 has suitable driving means such as a slot or knurls on its head and in this embodiment of the invention is provided with a conical clamping face on the under surface of said head. The shank of the screw has an unthreaded portion 24 of considerable extent adjacent the clamping surface 22 and a threaded portion 26 extending to the free extremity of the screw.
Rotatably assembled to the screw 16 is the clamp 14. In the present instance, the clamp 14 includes a centrally apertured dished or conical central section 28 with the concave side thereof facing the conical clamping surface 22 of the screw 16. A pair of arms 30 extend outwardly and downwardly from opposite sides of the central section 28 and are adapted to be accommodated within the slots 20. The material from which the clamp 14 and its arms 30 are formed is preferably of a thickness substantially less than the width of the slots 20 for purposes "ice best set forth hereinafter. To rotatably assemble the screw 16 with clamp 14 suitable means known to the art such as an annular rib or shoulder 32 is provided at the junction of the unthreaded shank portion 24 and the threaded shank portion 26. Shoulder 32 is greater in diameter than the aperture in the clamp 14 whereby upon retrograde movement of the screw 16 relative to the base 12, the rib 32 comes into contact with the convex side of central portion 28 and moves the clamp 14 upwardly away from the base 12. In the operation of this device, one or more wires 34 can be inserted in the passageway formed between the base 12, the leg 30, the central portion 28, and the screw 16.
In the event that two wires of equal diameter are not utilized the connector is adapted to compensate either for two wires of differing diameters or to the use of a single wire with the connector and bus bar. To accomplish this, the included angle of the conical clamping surface 22, when taken in section, is less than the included angle of the conical surafce 28 whereby the clamp 14 is free to cant as best seen in FIG. 2 where wires having dissimilar diameters are utilized. The variation in thickness of the clamp material relative to the width of the slots 20 permits limited angular movement of the arm 30 within said slots 20 as shown in FIG. 2. As a safety precaution, so that the clamp 14 cannot be completely removed from the base 12, the last thread at the free extremity of screw 16 can be distorted as indicated at 36 by peening the end of the screw or by other suitable means.
The device is extremely simple to operate since the clamp means can be jacked away from the bus bar by mere rotation of the operator or screw whereby the personnel installing the wires do not have to physically manipulate the connector in any fashion other than by rotation of the screw. The device is economical to manufacture since it can be made from stamped parts and is ideally suited for use in close, tight quarters.
While modifications or embodiment of this invention will be apparent to those skilled in the art, it is not intended that it should be limited in any fashion except by the appended claim.
An electrical connector including a base portion formed from one end of the parent material of a bus bar, a rotary screw threaded fastener, a screw threaded aperture in said base portion for telescopically accepting said rotary screw threaded fastener, clamping means rotatably as sembled with said rotary screw threaded fastener and adapted to overlie one face of said base portion, a pair of transversely extending slots in said base means positioned in spaced relation on opposite sides of said threaded aperture, said clamping means being strap-like and substantially uniform in Width throughout its length and including a body portion overlying said one face of said base portion, said body having a medially apertured dished central portion with the concave side facing upwardly and the convex side facing said one face of the base portion, a pair of arms extending outwardly and thence downwardly from said dished portion and adapted to be telescopically accepted in said two slots, said rotary threaded fastener being a screw provided with a conical clamping surface under its head and an unthreaded shank portion adjacent said head, said conical clamping surface being adapted to be seated in the concave side of the dished portion when the shank is telescopically accepted within the medial aperture, said concave side having a greater apical angle than the apical angle of the conical clamping surface under the screw head, means on said screw shank in the vicinity of the unthreaded shank portion and its juncture with the threaded portion of said shank adapted to accomplish permanent rotatable assembly of said clamping means on said screw, the aperture in said clamping means being larger in diameter than the unthreaded shank portion of said screw, said slots in said base portion being greater in lateral extent than the thickness of material in said depending arms of said clamp means whereby the introduction of wires of dissimilar diameters under the opposed outwardly extending portions of said arms will result in a canting of said clamp means to compensate for said difierence in diameters, but will assure positive clamping relative to said base means, the convex side of said central dished portion extending downwardly into the clamping region to cause the convex side to impinge upon said wires to be clamped whereby said clamping means is centrally reinforced by the dished portion and said wires are forced laterally into engagement with the downwardly extending portion of said arms and said rotatable assembly of the screw to the clamp means facilitates jacking of the clamp means away from said base means upon retrograde movement of the screw References Cited in the file of this patent UNITED STATES PATENTS 490,755 Russell Jan. 31, 1893 1,386,634 Kruse Aug. 9, 1921 1,807,462 Zehnder May 26, 1931 2,136,366 Martin Nov. 15, 1938 2,216,344 Hampton Oct. 1, 1940 2,236,279 Van Hoorn Mar. 25, 1941 FOREIGN PATENTS 220,315 Switzerland Nov. 2, 1942 269,917 Switzerland Nov. 1, 1950 632,048 Great Britain Nov. 15, 1949 812,562 Germ-any Sept. 3, 1951