US743607A - Resistance for electric circuits. - Google Patents

Description

No. 743,607. PATENTED NOV. 10, 1903.

G. WRIGHT.

RESISTANCE FOR ELECTRIC CIRCUITS.

APPLICATION FILED JULY 15, 1902. RENEWED SEPT. 26, 1903.

N0 MODEL.

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UNITED STATES Iatented November 10, 1903.

PATENT OFFICE.

GILBERT WRIGHT, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO THE STANLEY ELECTRIC MANUFACTURING COMPANY, OF PITTSFIELD, MASSACHUSETTS, A CORPORATION OF NEW JERSEY.

RESISTANCE FOR ELECTRIC CIRCUITS.

SPECIFICATION forming part of Letters Patent No. 743,607, dated November 10, 1903.

Application filed July 15, 1902. Renewed September 26, 1903. Serial No. 174,828. (No model.)

To aZZ whom it may concern:

Beitknown that I,GILBERT WRIGHT, a citizen of the United States,residing at Pittsfield, in the county of Berkshire, State of Massachusetts, have invented certain new and useful Improvements in Resistances for Electric Circuits, of which the following isa full, clear, and exact description.

My invention relates to resistance for use in electric circuits.

Among the objects of myinvention are compactness, strength, and durability of construction.

In addition to providing a resistance possessing superior structural features the arrangement of the parts is such that they all may be readily assembled and firmly held in permanent and fixed position save as to any part or parts intentionally made movable. Conspicuous among the features of improvement is the new form of the resistance unit, the method of mechanically connecting a plurality of these units together, and the method of holding the same in place.

In the drawings,Figure 1 is an end elevation of a resistance-box embodying'my invention the end plate being partly broken away to show features of internal arrangement. Fig. 2 is a cross-sectional elevation of the parts shown in Fig. 1, but showing one grid or resistance unit only with part of another. Fig. 3 is a perspective view of a grid or unit of resistance.

A and B represent main terminal wires of an electric circuit. The current may be considered as passing in through the wire A. The wire Ais electrically connected, for example, by means of a binding-post C and a metallic strip C, with a brush D, which is centrally mounted and has a rotary movement, said movement being given by means of a revoluble shaft D or by any other suitable means. The binding-post C may have at its outer end contact-studs C which may stand slightly above the surface of an end plate G, Which is preferably formed of insulating material. The terminal B is suitably connected to the last of a series of resistancegrids (to be hereinafter described) and may have contact-studs (not shown) similar to the contact-studs C E E are resistance units or grids formed of suitable resistance material and formed, for example, substantially as shown in Fig. 3, so as to reduce into comparatively small space a resistance of considerable length, the contortions being arranged in substantially one plane. The units E are arranged in series and are connected, preferably, by means of bolt-screws F, the heads of which may perform the additional function of contact-studs F F. The studs C F are arranged inacir cle within the radius of the brush D. Each stud F is in electrical. connection with one end of each of two adjacent grids. The grids are arranged in series, each grid being electrically connected to a preceding and a succeeding grid. The grids are arranged in radial planes from the center of the box and are mechanically connected or held in such manner that there is no danger of their being accidentally thrown into contact with each other. In the preferred form each grid is held at four points.

In Fig. 2 the additional reference-letter E is used to signify one end of one grid located beyond the grid E therein shown. It will be seen that the end of the grid E (shown in Fig. 2) fits down over the shank of the screw F, while the adjacent end of the grid E fits onto the screw-threaded portion of the shank F and is drawn down against the end E, so as to electrically connect the three parts F, E, and E. The other end of the grid E (broken away in Fig. 2) may be held by another screw in the same manner as the end E. It will be seen that there is a mechanical connection for each end of each grid. Intermediate in the length of the grid E may be formed a point e, which may take into a ring H, of insulating material, held in position by means of a flange J upon the end J of the box. This insulating material II may be of hard asbestos and may be backed with a ring of soft asbestos H. On the opposite side of the grid E a second point e is provided,- which may take into a cavity in the rear of the plate G. As shown, each grid is securely held in place at fourpoints. Hence there is no danger of dislodgment and shortcircuit. When the switch is in the position shown in Fig. 1, all of the resistance units are in circuit, the current flowing from A to the brush D, thence to the stud or studs C and thence through the series of radially-arranged grids to the terminal 13. To cut out the resistance, the brush D is revolved so that it will move successively over the contact-studs. Inasmuch as the current always passes through the brush D, it follows that when the brush is moved clockwise from the position shown in Fig. 1 one after another of the resistance units will be cut out until finally, when the brush rests upon the contact-studs connected directly with the terminal B, none of the units are in circuit. The reverse movement of the brush cuts in one resistance after another. In order to prevent jumping from no resistance to maximum resistance, a stop K may be provided located in the path of movement of the brush and between the terminals A B. The grids may be made of cast-iron and in this form present a durable and economical unit.

What I claim is 1. In a resistance for electric circuits, a plurality of. cast grids arranged in radial planes, and retaining-lugs cast on said grids at points between the ends of said grids.

2. In a resistance for electric circuits, a plurality of cast grids arranged in radial planes, retaining-lugs cast on said grids at points between the ends of said grids, and a ring of insulating material engaging said lugs.

3. In a resistance for electric circuits, a plurality of cast grids arranged in radial planes, an end plate of insulating material, a ring of insulating material, and lugs cast on said grids at points between their ends adapted to engage said end plate and said ring.

4. In a resistance for electric circuits, a plurality of cast grids arranged in radial planes,

retaining-lugs cast on said grids at points between their ends, and an end plate of insulating material adapted to engage said lugs.

5. In a resistance for electric circuits, a plurality of cast grids arranged in radial planes and connected in series, an end plate of insulating material, a ring of insulating material, and lugs cast on said grids at points between their ends adapted to engage said end plate and said ring.

6. In a resistance for electric circuits, a plurality of grids cast in the form of a strip bent back and forth on itself in parallel lines, the ends of said grids being at right angles to the direction of the parallel lines and one of said ends being inclined to the plane of said parallel lines.

7. In a resistance for electric circuits, aplurality of grids, arranged in radial planes, said grids being cast in the form of a strip bent back and forth on itself in parallel lines, the

ends of said grids being at right angles to the direction of the parallel lines and one of said ends being inclined to the plane of the parallel lines, and means for connecting said grids in series.

8. In a rheostat, a supporting member, a plurality of rigid resistance-conductors, bolts fol-securing said resistance-conductors to said support, each of said bolts being arranged to secure one terminal of each of two resistanceconductors to said support, the heads of said bolts being arranged to serve as contact-studs, and a movable switch for engaging said heads.

9. In a resistance for electric circuits, a plurality of rigid resistance-conductors arranged in radial planes, retaining-lugs on said conductors at points between the ends of said conductors, and a plurality of clamping devices for securing the conductors to the supporting member, each clamping device securing one end of each of two adjacent conductors to the support, and portions of said clamping devices serving also as contact members.

10. In a rheostat, a supporting member, a plurality of rigid resistance-conductors arranged with the ends of said conductors lying in the arc of a circle, one end of each resistance-conductor placed between the support and one end of the adjacent conductor, and a plurality of clamping members, each of said clamping members securing one end of each of two conductors to the support.

11. In a rheostat, a plurality of rigid counterpart resistance-conductors, each of said conductors having a reflex portion which lies in one plane, the reflex portions of the conductors being arranged in radial planes and the ends of the conductors being brought into the arc of a circle, a support, and a plulality of bolts for clamping the conductors to the support, each of said bolts securing one end of each of two adjacent conductors to the support, and the heads of said bolts serving as contact-studs.

12. In a resistance forelcctric circuits,a plurality of rigid resistance members arranged in radial planes, said members being in the form of a strip bent back and forth on itself in parallel lines, the ends of said members being at right angles to the direction of the parallel lines and one of said ends being inclined to the plane of the parallel lines, and bolts for connecting said members in series, the heads of said bolts serving as contact members.

Signed at Pittsfield, Massachusetts, this 9th day of July, 1902.

G1 LBE RT \V RIGHT.

Witnesses:

ARTHUR E. JENNEY, GEORGE W. HAMILTON.

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