US1726476A - Resistance element - Google Patents

Description

27, R. R. DUNLOP 5,

RES I STANCE ELEMENT Filed March 8, 1924 Patented Aug. 27, 1929.

UNITED STATES 1,726,476 PATENT OFFICE.

ROBERT R. DUNLOP, OF COLUMBUS, OHIO, ASSIGNOR TO THE JEFFREY MANUFACTUR- ING COMPANY, OF COLUMBUS, OHIO, A CORPORATION OF OHIO.

RESISTANCE ELEMENT.

Application filed March 8, 1924. Serial No. 697,795.

The present invention relates to certain new and useful improvements in resistance elements adapted to use with electrical apparatus subject to the severe service conditions encountered in electric traction, mining machinery, and the like.

The especial object of this invention is to provide a wire resistance adapted to withstand the high temperature and mechanical strains, having the necessary electric qualities combined with economy of manufacture, durability under the most severe service conditions, and convenience of application to the apparatus of which it forms a part.

The means whereby I attain this objectare fully set forth in the following specification and illustrated in the accompanying drawings of which Fig. 1 is a side elevation of the preferred embodiment of my invention.

Fig. 2 is a plan view, partly in section, of the devices illustrated in Fig. 1.

Fig. 3 is a fragmentary sectional view taken along the line III of Fig. 1.

Fig. 4 is a cross section taken along the line IVIV of Fig. 1.

Like numerals refer to similar parts in the several figures.

As shown in the drawings my improved resistance element comprises a resistance wire 1, preferably formed of metal having high specific electric resistance combined with heat resisting qualities, which is wound in a laterally flattened coil, and is mounted upon a framework of peculiar construction. The supporting framework comprises the end bars 2 and the longitudinally extending rods 3 which project through suitable apertures in said end bars and are insulated therefrom by the insulating tubes 4. which may be formed of any preferred heat resisting insulating material. Mounted upon the tubes 4 are series of collars 5, preferably formed of porcelain or other approved heat resisting insulating material, the peripheries of which approximately conform to and engage the curved ends 6 of the loops of the resistance wire 1. On each of the collars 5 is formed a flange 7 adapted to extend between adjacent turns of the wire 1, and of sufiicient thickness to insure the desired spaced relation of said turns. Suitable insulating washers 8 and 9 are mounted upon the tubes 4 at the sides of the bars 2, and nuts 10, threaded to the rods 3, serve to clamp the several elements securely together. Attachment members 11, which may be of any preferred form, mounted upon the rods 13 between the washers 9 and the nuts 10, afford means for the attachment of my improved resistance unit to any suitable and convenient support. The ends of the wires 1 are preferably connected to the end bars 2 which are provided with suitable binding posts 12 for their connection with the conductors of an outside circuit. In the drawings I have shown the method of attaching the Wires 1 to the bars 2. As here shown the wires 1 are clamped under the lugs 13 formed on the bars 2 and are secured thereto by soldering, electric welding, or other preferred mechanical means.

In the above described devices I have provided a wire resistance element having approved electrical and mechanical properties of relatively inexpensive construction extreme durability and reliability in service, and of such flexible design that it may be readily adapted to the limitations of the apparatus with which it is to be used.

What I claim is 1. In a resistance unit, the combination wit-h a resistance wire wound in an open coil, of a supporting frame therefor comprising end members electrically connected with said wire, rods extending longitudinally of said coil through apertures of said end members, a continuous insulating tube mounted on each rod and extending substantially from end to end thereof and through said end men"- bers. a plurality of insulating collars mounted upon said tubes to engage the loops of said coil, a flange formed upon each collar projecting between adjacent loops, and means to clamp said end members against said collars as and for the purpose set forth.

2. In a resistance unit, the combination with a resistance wire wound in an open coil, of a supporting frame therefor comprising end members electrically connected with said wire, means upon said end members to connect them with the conductors of an external circuit, rods extending longitudinally of said coil through apertures of said end members, a continuous insulating tube mounted on each rod and extending substantially from end to end thereof and through said end members, a plurality of insulating collars mounted upon said tubes to engage the loops of said coil, a flange formed on each collar projecting between adjacent loops, and

nuts threaded upon said rods adapted to clamp said end members against said collars as and for the purpose set forth.

3. In a resistance unit, the combination With a frame including electrical conductor end members, rods extended through said end members, a continuous insulating tube mounted on each rod and extending substantially from end to end thereof and extended through said end members to insulate them from said rods, and a resistance element wound in open coil upon said insulated rods and having its ends electrically connected t said conductor end members.

4. In a resistance unit, the combination with a frame including electrical conductor end members, rods extended through said end members, a continuous insulating tube mounted on each rod and extending substantially from end to end thereof and extended through said end members to insulate them from said rods, a resistance element wound in open coil upon said insulated rods and having its ends electrically connected to said conductor end members, attachment members mounted upon said insulating tube and being insulated from said end members, and means on the ends of the rods for clamping the supporting and attachment members in position.

5. In a resistance unit, the combination with a frame including electrical conductor end members, each having a. pair of apertured spacing bosses, rods extended through said bosses, a continuous insulating tube mounted on each rod and extended through said apertured bosses to insulate said con- ROBERT E. DUNLOP.

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