US662501A

US662501A - Safety cut-out for electric circuits.

Info

Publication number: US662501A
Application number: US73189799A
Authority: US
Inventors: Joseph Sachs
Original assignee: Individual
Current assignee: Individual
Priority date: 1899-09-28
Filing date: 1899-09-28
Publication date: 1900-11-27
Anticipated expiration: 1917-11-27

Description

J. SACHS.

SAFETY CUT-OUT FOR ELECTRiC CIRCUITS.

(Applicntion med Sept. 28, 1899.)

(No Model.)

Patented Nov. 27, I900.

I E O l l o UNITED STATES PATENT EEIcE.

JOSEPH SACHS, OF HARTFORD, CONNECTICUT.

SAFETY CUT-OUT FOR ELECTRIC ClRCUlTS.

SFECIFTGATION forming part of Letters Patent No. 662,501, dated November 27, 1900.

Application filed September 28, 1899. Serial No. 781,897. \No model.)

To all whom it may concern:

Be it known that l, JOSEPH SACHS, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connectiout, have invented an Improvement in Safety Cut-Outs for Electric Circuits, of which the following is a specification.

My invention relates to a fuse device adapted to operate with the smallest and most delicate electric currents. I-Ieretofore it has been difficult if not quite impossible to produce fuses sensitive to exceedingly-small electric currentssuch, for instance, as are employed for telephones, telegraph instruments, firealarms,and similar apparatus. My improved safety-fuse or cut-out is adapted for use generally, but particularly with instru ments and in places where the smallest electric currents are employed, the fuse being adapted to open the circuit at very small overload electric currents, and the arrangement is exceedingly simple, cheap, and efficient.

In carrying out my present invention 1 provide a section orpiece of high-resistance heating material-such as graphite, or carbon, or metal-and to this is connected a portion or Wire which is of comparatively low resistance or melting-point. These parts are in one line and preferably provided with suitable terminals and within a case of suitable insulating material. In this case the wires may be suspended between the terminal ends and the case may be tubular, and it may be wholly or partially filled with some suitable material, such as the material heretofore shown and described by me in former applications. The portions or wires extending from the opposite ends of the section of high-resistance material may be entirely straight or partially or wholly coiled. Where the wires are coiled, they are preferably short lengths, either connecting the circuit connections or metal terminals with the ends of the Wires that are connected to the high-resistance material or extending between the high-resistance material and one circuit connection, and the special object of the coils is to normally produce a tension upon the intermediate parts, so as to maintain them in a suspended condition without perceptible sagging and to pull the parts asunder when fused under an excess current. The metal terminals or circuit connections may be either notched plates or the metal ends or caps of the inclosing case of insulating material. The case or inclosure for the wires may be tubular and of insulating material or a fiat strip of insulating material with an open center. The ends of the wires may be connected to the piece of high-resist ance material in any desired manner well known in the arts, particularly those hereinafter set forth.

In the drawings, Figure 1 is an elevation of the fuse device alone. Figs. 2 and 3 are elevations of modified forms of the fuse device alone. Fig. i represents the fuse device in an inclosing' tubular case. Fig. 5 represents the fuse device in an insulating holder having an open center, and Fig. U represents a modification of the fuse device alone.

The wire or wires a are of some comparatively low melting or resistance metal,through which the current is conductedsuch, for instance, as lead, tin, zinc, copper, or suitable alloys of the same. The short section of highresistance heating materialb such as graphite, carbon, or similar material or a com pound or metal whose melting-point is very much higher than that of the wire ahas one of the ends of the wire connected to it. This connection may be by twisting the ends of the wire a around the section b or by clamping it thereto or by soldering the end of the wire a to the end of the section b.

in Fig. 1 one end of the section b is con nected directly to one terminal and the other end to a wire a, while in Fig. 2 the respective ends of the section bare connected to the wires a, which in turn are connected to the terminals or circuit connections. Vifhere the section b is of graphite or carbon and the ends of the wires a are soldered thereto, it is preferable that the section b be first electroplated. The soldering material may be of any suitable character well known in the arls, and in cases where the wires a co are of lead they may be connected to the section b without solder, their ends being simply melted to a connection with the section b, or, in other words, joined directly when the proper degree of heat is applied.

The terminals or circuit connections 0 may be notched plates, as shown in Figs. 1, 2, 3, and 6, or end caps d, as shown in Fig. -l-, or

plain plates 6, as shown in Fig. 5. The ends of the wires a a may be connected directly to the circuit connections or terminals 0, as shown in Fig. 2, or one of them may be connected directly, as shown in Fig. 6, or I may employ coilsff between the ends of the wires d and the terminals or circuit connections, as shown in Figs. 3, 4, and 5, or I may employ only one coil, as shown in Fig. (5, and extend the same between the section b and the terminal c. The special object of the coils f, which, by the way, are preferably made of metal having a degree of spring thereto, is to normally apply a tension to the wires to and section 1) between the terminals, so as to hold the same in an approximately straight line.

In Fig. 4 I have shown a surrounding case 9, of insulating material and of tubular form, with circuit connections or terminals (1 in the form of end caps of metal fitting over the open ends of the tubular case, with the ends of the coils connected directly to the end caps and the wires a and section I) under tension and centrally of the said case J.

In Fig. 5 I have shown a case or holder 7A, of a flat strip of insulating material, with an open center and with plate-terminals e in the respective ends of the holder h and in which the coilsf maintain the wires CL and section I) under tension and centrally of the holder h.

The tubular case g, of insulating material, may be glass, rubber, fiber, asbestos, or similar suitable substance and the metal caps at the ends serve as the terminals themselves, and they may be connected to any suitable foundation similar to what has heretofore been shown in my other applications and patents. The interior of this tubular case 5 may be unfilled or may be filled by any suitable material or it may be divided and partially filled, as has heretofore been customary with me in similar devices.

In the operation of this device the current passes from one end to the other between the terminals or circuit connections and over the wires a and the section b, and the parts are so proportioned that the wires to Cb are scarcely heated at all by the passing of the electric current, but the section b is considerably heated. This is due to the fact that the section 1) consists of a concentrated resistance, and while it may not be of any great length yet the heat generated by the section b where the parts are properly proportioned will even with the smallest overload electric current be enough to melt the'connection between a wire a and the section Z) either in severing the wire connection or in melting the solder, so that there is a separation of the parts which breaks the electric circuit. In cases where the coiled terminal wires are used this disj ointing is really assisted bythe tension kept upon the fuse-wire, so that as soon as suflicient heat is produced from the overload-current the parts will be pulled asunder. I prefer to employ a tubular case, as shown in Fig. 4, be cause the same is the most satisfactory and the best adapted for the purposes, as thereby the same protects the fuse device from all aircurrents and contact with other bodies, and therein the fuse device is supported in a medium the condition and character of which are not readily changed or affected by outside conditions.

I do not limit myself to the supporting device for the safety cut-out or to the manner of connecting the ends of the wires or coils to the piece Z) of high resistance or to the form of the circuit connections or terminals.

I claim as my invention 1. A safety-fuse comprising two connected portions in one line for the passage of the electric current, the one portion. a section of material of low conductivity to be heated and the other portion a piece of material of high conductivity connected by a joint fusible by an excess of heat of the low-senductivity section, substantially as specified.

2. The combination in a safety-fuse with circuit connections and the fusc-wirc connected thereto, of a section of graphite, carbon or similar high-resistance heating material to which the fuse-wire connected by a joint fusible by the action of excess of heat of the heating-section substantially as spccilied.

3. A safety-fuse comprising two connected portions in one line for the pr of the electric current, the one portioi material of low conductivity to l' heated and the other portion a piece of material of high conductivity connected by a join t .iible by an. excess of heat of the low-cowluctivity section, and a means for effecting nsion for the separation of the parts, substantially as specified.

-l-. A safetyfnsc comprising two connected portions in one line for the passage of the electric current, the one portion a section of material of low conductivity to be heated and the other portion a piece of material of high conductivity connected by a joint fusible by an excess of heat of the low-conductivity section and a tubular case holding the said parts, and terminals to which the endsthereof are connected, substantially as specified.

5. The combination in an electric safetyfuse with a higlrresistanee heating-section, of a coiled wire connected electrically and mechanically by a fusible joint to and in one line with the high-resistance section and by which a tension is normally effected on the parts and a separation when the resistancesection has been heated to excess and the fusible joint melted, substantially as and for the purposes set forth. I

G. The combination in a safety-fuse, with circuit connections and the fnse-vires, of a short section of graphite, carbon or similar high-resistance material interposed between the fuse-wires and to which the ends of the same are connected by a joint fusible by an excess of heat of the higlrresistance material, substantially as specified.

7. The combination in a safety-fuse with circuit connections and the fuse-Wires connected thereto, of a short intermediate section of graphite, carbon or similar high-resistance material electroplated and to which the respective ends of the fuse-Wires are soldered, substantially as set forth.

8. The combination in a safety-fuse with the fuse-Wires, of an interposed section of high-resistance material to which the fuse- Wires are connected, circuit connections and coils connecting the respective circuit connections and the free ends of the fuse-Wires, substantially as set forth. 7

9. The combination in a safety-fuse with a tubular case of insulating material and metal circuit connections or terminals at the re spective ends thereof,of fuse-Wires connected to the said terminals Within the case and an interposed section of high-resistance material connected to the fuse-Wires Within the case by a joint fusible by an excess of heat of the high-resistance material, substantially as set forth.

10. The combination in a safety-fuse witha tubular case of insulating material and metal end caps forming circuit connections orterminals, of the fuse-Wires, an interposed section of high-resistance material connected to the fuse-Wires and coils connecting the ends of the fuse-Wires to the end terminal caps, sub stantially as set forth.

11. The combination in a safety-fuse with a holder of insulating material and metal circuit connections or terminals at the respective ends thereof, of fuse-wires connected to the said terminals and an interposed section of high-resistance material connected to the fuse-Wires by a joint fusible by an excess of heat of the high-resistance material, substantially as set forth.

Signed by me this 21st day of September, 1890.

JOSEPH SACHS.

Witnesses:

Gno. T. PINCKNEY, S. T. HAVILAND.