US1743888A - Electrical connection - Google Patents

Description

ucnfoi;

V. C. HAMISTER ELECTRICAL CONNECTION 1 C. H H

. .v C .w m n M N A Jan. 14, 1930.

Filed April 25", 19 N i atented Jan. l t, 1%30 UNETE D STATES FATENT VICTOR C. HAIHSTEP, (3F @LEVELAND, onto, ASSEGNUR T NATIGNAL CAREGE' C(DEE .WANY', INQ, A @QEPORATEGH DE NEW YORK ELEGTRIGAL CQNNECTZQEZT Application filed April 25,

The invention is a form. of electrical connection, cheaply and easily made, and having a permanently low resistance.

ln accordance with the invention, the pair 5 of conductors to be connected are held together under pressure with a pad of felted metal fibers between them. The fibers, before placing them between the conductors, may be in a loose and uncompressed mass. The conductors may be separated widely enough to permit the easy insertion of the mass of iibers, or the conductors may be closer together, the loose fibers being stuffed into the gap between them.

I prefer, however, to compress the fibers rather strongly in one direction as a preliminary operation, to form a more or less compact pad, since a layer of fibers which is uniform in thickness and of the desired shape can be more easily prepared at a place where the conductors do not interfere with the op eration, and a pad of metal fibers is much more simple to handle, especially where space is limited, than is a loose mass of fibers. In any of the cases mentioned above, the connection is completed by pressing the conductors strongly together.

Steel wool is well adapted for use in my invention, though any other metal or alloy, 30 ferrous or non-ferrous, which can be shred ded, may be used. The choice of the fibrous metal to be used will depend on the temperature, corrodin-g influences, and other conditions to which the connection may be sub jected. Fibrous copper has advantages under some conditions and lead wool under others. Steel wool may be formed into suitable pads by distributing the proper quantity uniformly over the desired area, and then ap- 40 plying a pressure of about 4000 pounds per square inch. When a pad is formed from the fibrous -metal as a preliminary step, this pad may 1 be of any appropriate shape, and may be perforated if desired. A simple annulus or washer will be applicable in many instances.

The invention may be used with special advantage where one or both the conductors to be joined are carbonaceous, e. g. graphite. It is expensive to machine such conductors to 1928. Serial No. 834,562.

an accurate fit; their low mechanical strength limits the force with which they can be pressed together; and they do not possess the plasticity and pliability which, in the case of copper and other soft metals, causes contacting surfaces to conform closely when pressed together. The accompanying drawing shows two sections of a graphitized furnace electrode, joined in accordance with my invention. In the drawing,

Fig. 1 is a longitudinal section of the connection, and

Figs. 2 and 3 are perspective views of the two shapes of fibrous metal pads used.

E and E are the electrode sections which have the female threaded frusto-conical cavities C and C formed in their respective abutting ends. A dowel D, having tapered and threaded sections fitting the cavities C and C, is screwed into one of the sections and the other section is screwed onto the dowel.

Between the ends of the dowel and the plane bot-toms of cavities C and C are the circular pads of compacted steel-wool A, while between the abutting ends of the electrode sections, and around the dowel, is the annular pad B of the same material. The sections are merely screwed onto the dowel with as much force as the threads will safely stand, and if the thicknesses of the pads of steel wool and the clearances designed to re ceive them are even approximately properly proportioned, a highly satisfactory connection will result. A much better connection can be made with less accuracy in machining the parts than when the steel-wool pads are not used.

. The invention can also be used to produce a low-resistance connection between carbon or graphite brushes and conductors to be connected therewith; between bus-bar sections; between battery terminals and contacts in casings designed to receive the batteries; be tween furnace or lamp electrodes and holders therefor; and for a wide variety of other electrical connections. The invention is not limited, except by the appended claims.

I am aware that cables have been connected to brushes by inserting the cable end into a cavity in the brush and then tamping 2. 1,74s,ess

the narrow annular ace about the cable full of short lengths wire. The ieces of wire become more or less entangle during this operation, but they have a uniformity of direction which is essentially different from the promiscuous disposition of the fibers 1n felts, including the felted metal fibers employed in my invention.

I claim: I 1. In an electrical connection, the combination of a pair of conductors screwed toether and a body oi closely com acted brous conducting material between t e conductors for ensuring low electrical resistance and preventing accldental unscrewing of the conductors.

a 2. In an electrical connection, in combination a pair of conductors having opposed threaded cavities therein, a dowelichreaded into both said cavities to oin the conductors, pads of metallic felt interposed between the ends of the dowel and the bases of the cavities, and a metallic felt washer surrounding the dowel and inter osed between the adja- 5 cent ends of the con uctors, the arrangement being such that the dowel and the conductors are caused to press against the pads and the conductors are caused to press against the washer by the screwing of the dowel into the so conductor cavities.

' 3. In an electrical connection, the combination with a pair of conductors, one of said conductors having a projection thereon and a shoulder surrounding said projection, the

other of said conductors having a recess for receiving said shoulder, of a body of closely compacted metallic fibers surrounding said prqection and compressed between said shoulder and the face of said second named '40 conductor.

4. In an electrical connection, the combination with a pair of electrical conductors having opposed faces, of an annulusv of close] compacted metallic fibers between said aces and means extending through the hole in said annulus forcing said conductors towards each other and compressing said annulus.

' In testimony whereof, I afix my signature.

5o VICTOR C. HAMISTER.

Images