US718660A - Thermal electric cut-out. - Google Patents

Description

PATBNTED JAN'. 20, 1903.

T. E. SGANTLTN. V THERMAL ELECTRIC GUT-OUT.

APPLICATION FILED SEPT. 5, 1901.

NO MODEL.

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UNTTED ySTATES ATENT OFFICE.

THOMAS E. SCANTLIN, OF LAFAYETTE, INDIANA.

THERMAL ELECTRIC CUT-OUT..

SPECIFICATION forming' part of Letters Patent No. 718,660, dated January 20, 1903 Application tiled September 5, 1901. 'Serial No. 74,411- (No model.)

To all whom, t may concern,.-

Beit known that I, THOMAS E. SoAN'rLlN, a citizen of the United States, residing at Lafayette, in the county of Tippecanoe and State of Indiana, have invented certain new and usefullmprovementsinThermalElectricCut- Outs; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a thermal electric cut-out primarily designed for protecting telephone and telegraph instruments and equipments from sneak currents of higher potentiality or amperage than suchinstruments and equipments are designed to withstand, but capable also ot' being employed effectuallyT as a current-arrester in electric circuits and connections of all kinds where protection from abnormal currents is or may be found necessary or desirable.

The object of the invention is to provide a thermal cut-out which is simple of construction, inexpensive of production, and quick-acting.

Vith this and other objects in view, which will appear as the nature of the improvements is better understood, the invention consists of certain novel features of construction, combination, and arrangement of parts, as will be hereinafter more fully described, and particularly pointed out in the appended claims.

In the accompanying drawings, Figure 1 is a perspective view of a cut-out embodyingmy invention. Fig. 2 is a longitudinal section of the same. Figs. 3, 4, 4a, 5, 6, 7, and 8 are views similar to Fig. 2, showing modiiied forms of the cut-out; and Fig. 9 is a view showing the application of the invention to its supports.

Referring now more particularly to Figs. l and 2 of the drawings, the letters a b indicate the terminals of the cut-out, and c its non-conducting casing or receptacle. The terminal ct has projecting therefrom a pin d, which enters the bore of a tube e, carried by the terminal b. The outer end of this tube has a threaded stem f, which iits within a threaded socket in a non-conducting bushing g, occupying the opening in the said terminal b, which is of ring form. The pin d is connected with the tube e by the fusible connection h, composed of solder or some other fusible material which will melt at a relatively low degree of heat. The terminals a and b close the ends of the receptacle c, and one or both of them may have an endwisesliding movement to withdraw the pin and tube from engagement when released by the melting of the said fusible connection. The space or chamber between the pin and tube and the wall of the receptacle contains a tilling of subdivided or aggregated resistance material z', which preferably consists of carbon, German silver, or some other suitable material of low conductivity and high resistance, said material being of pulverulent, powdered, or granular form in order to secure the best results. This material is in electrical connection with the terminals ct b, and when an abnormal current passes through the cut-out or arrester the resistance material becomes heated, and as the heat therefrom is transmitted to the pin and tube the solder or fusible connection between them is melted, leaving them free toY be withdrawn from engagement with each other by an endwise-sliding movement of one or both, as desired. The outer surface of the tube e is covered with a layer j of waxed paper, silk, or other suitable insulating material for the purposeof decreasing the exposed conducting-surface Yot' said tube to cause the current to pass through the resistance material throughout the length of the receptacle, thereby increasing the resistance and producing a higher degree of heat. This result is also promoted by the use ot the non-conducting bushing g and utilizing the resistance medium for electrically connectingthe two terminals, as shown. In the present instance I have shown the terminal b as adapted to be moved to withdraw the pin from engagement with the tube, which is effected by means herein- IOO pin and tube are connected as before by the fusible connection 7L', and the resistance material t envelopsV the same and is confined in l the casing c and electrically connects the terminals a. and Z9.

In the construction shown in Fig. -lt the two terminals t2 b2 are united by the fusible connection h2 with metallic cups or caps 7.3, which close the ends of the receptacle c2 and are fixed thereto in any desired manner. The resistance material i2 contained in said receptacle electrically connects the two terminals 0,3 b2 through the metallic caps 7c. When the resistance material is heated by the passage of an abnormal current, the heat is transmitted to the caps la and thence to the solder, which is melted and releases the terminals from said caps. If desired, however, the caps r may be fixed to or formed integrally with the terminals and releasably connected by fusible material h3, such as shellac or solder, to the ends of the receptacle, as shown in Fig. 4, so as to be disengaged therefrom with the terminals when the shellac or solder is melted.

In the construction shown in Fig. 5 the two caps r/ are united by the fusible connection 7L4 and are fixed to the inner ends ofthe sections 03 c4 of a two-part casing or socket, each section containing a filling of resistance material 3, and the outer ends of said sections are formed with threaded sockets m for the reception of screw-threaded stems n, on the terminals a3 ZF. By this construction the terminals are electrically connected by the resistance material, caps, and threaded stems, as will be readily understood. The heating of the resistance material and caps causes the fusible connection 7L to melt and release the two parts of the cut-out from engagement in an Obvious manner.

In the construction shown in Fig. 6 the caps t2 are fixed to the ends of the receptacle, as in Fig. 4L, and have conical sockets o, which project into said receptacle and receive conical projections p on the terminals a4 b4, the said conical sockets and projections being united by the fusible connection h5. The electrical connection between the two terminals is here made through the resistance material and the conical members. The operation of the device as thus constructed Will be readily understood from the foregoing description.

In the construction shown in Fig. 7 both the pin d5 and the tube e5 are insulated from the terminals d5 D5. The pin d5 is provided with a screw-threaded end d, which screws into the non-conducting bushing g5, which in turn is threaded into the terminal a5. The tube e5 is similarly provided `with a threaded stem e6, which fits within a threaded socket in the non-conducting bushing c7, which is screw-threaded into the end of the terminal b5. The pin fits within the tube e5, as in the construction shown in Fig. 2, and is held in place by solder or other fusible material.

The space between the tube e5 and the nonconducting' receptacle or casing c5 is filled with the resistance material or substance In the construction shown in Fig. 8 I do away with the receptacle or casing and unite the two terminals a6 b by an admixture of the subdivided or aggregated substance or material t, which is a conductor, with some suitable material such as shellac,rosin,glue, or waxwhich will bind the parts of the subdivided material together` and unite the terminals d6 h6. Upon the passage of an abnormal current through the terminals this admiXture will fuse or melt, and the terminals will thereupon separate, as will be readily understood.

Fig. 9 of the drawings shows one mode of mounting the cut-out and withdrawing the terminals for engagement upon the melting of the fusible connection, the withdrawal of one or both terminals from their normal position being deemed preferable to arrest the passage of any current, although the parts may be so disposed or constructed as to effect the positive cut-olf of the current in any other desired way. In Fig. 9 two conducting and supporting plates q q are mounted upon a suitable base R and are designed to be con- Vnected up in the telephone or telegraph or other circuit in any approved manner.

Each of these plates is slotted or formed with an open bearing at its upper end, as shown at s, to receive the coperating terminal a or b, which is grooved at 3 to receive the walls of said slot, whereby the cut-out, which extends longitudinally between the plates, is held from endwise movement. A spring det-ent t is also formed on each plate to bear upon the terminal and hold the same securely seated in the slot. The free end of the plate q,Wl1ich is of spring metal, is bent out of its normal position to engage the terminal b and is held under spring tension, so that when the fusible connection 77. is melted said spring by its retractile force will pull the terminal b outwardly, thereby withdrawing the terminals from engagement with each other. Either one or both of the terminals may be mounted in this or any equivalent manner, as desired, and the movable spring-plates upon resuming their normal position may be made to contact with a ground connection, thus throwing the current to the earth until the parts are again restored for operation.

It will be seen from the foregoing description that each embodiment of the invention herein disclosed consists of terminals separable by the action of heat and a resistance medium consisting of a subdivided material formed of aggregated parts, which on becoming heated effects the disconnection of the terminals, thereby cutting off the flow of the current. The specific kind or character of the subdivided material employed is immaterial so long as it is of sufficiently low conductivity to perform this function.

The resistance material may be made of IIO any desired subdivided substance or substances of low conductivity and high resistance. The use of carbon or German silver in granular form is preferred; but I have also secured good results from the use of a good conducting material in granular form admixed with a non-conducting material-such as shellac, rosin, glue, cement, or waX-so that the former shall be wholly or partially enveloped in the latter, the current passing from one grain or particle to another and arcing through the non-conducting envelop, thus exciting energy and increasing the resistance and production of heat.

It is to be understood that by the use of the terms subdivided resistance, granular resistance, resistance medium of aggregated parts, dac., I mean any resistance medium composed of combined parts or particles eitherloosely confined or bound together by a suitable cement and through which an electric current may pass by a step-by-step movement, as by jumping from one part or particle to another.

As an instance, as heretofore stated, I may use carbon or German silver in granular or powdered form or any other material of like low conductivity and high resistance. I disclaim the use of aggregated coils of resistancewire, as a multiple conductor formed of two or more coils would lessen the resistance to an objectionable degree and also materially increase the cost of construction.

The invention may be employed in electrical equipment of all kinds where the use of a current-arrester is required.

Having thus described my invention, what I claim as new, and desire to secu re by Letters Patent, is

I. An electric-current cut-out consisting of two separable bodies, an easily-fusible cement uniting the same, and a resistance medium of aggregated parts adapted to be heated by an abnormal current to fuse said cement and forming a broken or interrupted electrical connection of low conductivity between said bodies through which a current passes by jumping from part to part, substantially described.

2. An electric cut-out having terminals separable by the action of heat, and a resistance medium of aggregated parts adapted to be heated by an abnormal current to effect the separation, substantially as specified.

3. An electric-current cut-out consisting of an envelop having terminals separable by the action of heat and containing a loose granular resist-ance medium adapted to be heated by an abnormal current to effect the separation, substantially in the manner'specied.

t. An electric-current cut-out consisting of a receptacle, terminals, a fusible connection between the terminals, and a granular filler of resistance material within said receptacle to fuse said connection, substantially as set forth.

5. An electric-current cut-out consisting of a receptacle, terminals closing the ends of the receptacle, a fusible connection between the terminals, and a granular iller of a resistance material confined by the terminals Within said receptacle and adapted to fuse said connection, substantially as described.

6. An electric-current cut-out consisting of anon-conducting casing,two separable bodies, an easily-fusible cement uniting the separable bodies, and a filler of granular resistance material within the casing for fusing the cement to separate said bodies, substantially as set forth.

7. An electric-current cut-out consisting of a non-conducting casing, terminals closing the ends of the casing, a two-part separable connection between the terminals, one of said parts being insulated from its terminal, an easily-fusible cement uniting the parts of the separable connection, and a filler of a resistance material of aggregated parts within the casing, said iiller connecting the terminals and being insulated from one of the said parts of the separable connection, substantially as specified.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

THOMAS E. SCANTLIN.

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