US534699A - Electric resistance-card - Google Patents

Description

` (No Model.)

A. J. SHAW.

ELECTRIC RESISTANCE CARD.

[TLUQTY/ NMMMMMMMMMUMr Patented Feb. 26, 1895.

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Bf" C UNITED STATES PATENT Greifen,

ALTON J. SHAIV, OF MUSKEGON, MICHIGAN.

ELECTRIC RESiSTANCE-iCARDn SPECIFICATION forming part of Letters Patent No. 534,699, dated February 26, 1 895.

Application filed December 1,1894. Serial No. 530,588. (No model.)

To tZZ whom t may concern.-

Beit known that I, ALTON J. SHAW, a citizen of the United States, residing at Muskegon, in the county of Muskegon and State of Michigan, have invented certain new and useful Improvements in Electric Resistance- Cards, of which the following is a specification.

My invention consists in a novel construction of electrical resistances, as hereinafter set forth.

The invention is illustrated in the accompanying drawings, in whichy Figure lis a perspective view ofa resistance card, block, or section, embodying my invention, the conducting body being represented in the forrn of a flat strip or band, and a porA tion of the device being broken away to better show the construction. Fig. 2 is a similar View, representing the conductor as made of wire; and Figs. 3 and et are detail views which will be hereinafter referred to.

The invention is designed to produce a simple, cheap and durable resistance device, ca-

pabie of use alone, or as one of a group or series in a rheostat or current regulator.

In the drawings, A indicates a frame which is preferably of cast iron, andcompriscsthree bars a, b and c, the bar b being channeled on its inner face as shown in Fig.

B indicates a conductingstrip, which is'preferably made of hoop iron or other suitable tlat metallic tape or band folded back and forth upon itself, the several folds or layers being separated one from another by strips C of micanite or other good insulating material. rPhe ends of the folds and of the insulating strips C are covered or incased by strips D of mica, asbestos or other good insulating material, mica being preferred because of its good insulating qualities and its proof against injury by heat or by electrical action.

The folded band with the interposed strips and with the covering` strips D applied as` stated and as shown in Figs. l and 2, is inserted within the frame A in the manner indicated in Figs. l and 3, the lower strip or sheet D of insulating material fitting within the channel of the bar b of said frame.

rlhe folds of the band b and the interposed strips C are of such length that they, together with the upper or second strip or sheet D, come hush with the uppercnds of the bars a and o of frame A. To retain the folded strip and the insulating strips in place, I apply to the open side of frame A a sheet metal cap E, folded as shown in Figs. 3 and e, to form a channeled plate or bar, the sides of which extend downward over the insulating strip D and over the folded ends of the strip E sufficiently to retain said partsin proper relation to the frame A.

The upper ends of the bars aand b are provided each with an opening d, and the cap or cover plate E is secured to said arms by forc ing the metal of its side wings or flanges into said openings d by means of a punch or other suitable implement, in the manner indicated in Figs. l, 2 and 4:. This affords a cheap and secure fastening and one which may, if necessary, be broken or destroyed to permit the removal of cap E.

It will be observed by referring to Fig. l that the first fold of the band B lies in iinmediate contact with the bar d of frame A throughout its length, so that good electrical contact is established between the frame A and the conductor B at that point, but owing` to the insulation above described, electrical contact between the frame and the band is prevented at all other points, and consequently if contact be made with the frame A at. any point, a current can pass by band B only by traversing its entire length. rlhe other end of band B, that is, the end opposite that which is in contact with bar d, is provided with a metallic tongue or tab e, by which connection may be made with a second section or with a line or conductor as desired.

It would of course be possible, if less than the entire resistance of band B be desired, to make contact therewith at a point between its ends and at one end, but this will not ordinarily be desirable, although for heavy cnrrents when the resistance is low, the tongue or tab c may advantageously be attached to IOO in contact therewith, as hereinbefore described of one end only.

The frame A will be provided with suitably tapped holes F to receive screws or tap bolts by which to fasten the frame A to a suitable support.

In Fig. 2 I have represented the conducting band Bin the form of a Wire, one end of which enters a hole in the end bar of frame A, and is made fast therein by a Wedge pin h, by soldering or otherwise. The Wire in this case is Wound about insulating strips C, similar to those shown and described in connection with Fig. I, similar strips being also interposed between those about which the wire is Wound, to prevent folds of proximate Wound strips from making electrical contact. In all other respects the construction is the same as shown and described in connection with Figs. 1, 3 and 4, that is to say, the same insulating strips D and cap or cover plate E are used, and the latter is secured to the frame A by punching or indenting its side flanges so as to forni eyelets or burrs within the openings e.

In the foregoing description I have relferred to the plate E as constituting the npper side ofthe frame A, but it is to be understood of course that this expression has reference only to the position in which the figures appear in the drawings, it being obvious that any one of the four sides ot' the frame may be made in the form of the cap or cover plate E. If, as in Figs. l and 2, the end plate instead of the side should be made of sheet metal, two paralled sides of frame A would of course be cast With grooves or channels.

In practice it is preferred to make contact or electrical connection with the resistance through the frame A, which is ordinarily done through one of its end bars, as a in the accompanying drawings; but if desired, the conductor may be entirely insulated from the frame and both its ends brought out in the same manner as the one end in Figs. l and 2.

I do not broadly claim herein a resistance device in which the conductor is formed of a flat metallic band or tape folded back and forth upon itself, nor, broadly, one composed of Wire wound about an insulating body.

Having thus described my invention, what I claim isl. A resistance section, card, or block comprising a channeled open frame A, a coiled or folded conductor having its folds insulated from one another and mounted within said frame, and insulating material interposed between the conductor and the frame, substantially as described and shown.

2. A resistance card or section consisting of a frame A having a channeled bar l), a folded conductor B having its folds insulated one from another and inserted within the frame A, insulating strips D inclosing the ends of the conductor folds, and a removable cap plate E applied to the frame and serving to retain the conductor therein.

3. In combination with a frame having openings d, a conductor mounted Within said frame, and a separate cap plate E applied to said frame and secured thereto by indenting or forcing the metal of its Hanges into the openings d'.

it. A resistance card, block, or section, comprising an open frame, a separate cap or bar applied to said frame and forming one wall thereof, and a conductor mounted Within said frame and held in place by the detachable cap or bar, substantially as described and shown.

In Witness whereof I hereunto set my hand in the presence of two Witnesses.

ALTON J. SHAlV.

Witnesses:

F. S. VROOMAN, THos. C. AKIN.

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