US1938119A - Temperature actuated circuit closing device - Google Patents

Description

Dec. 5, 1933. H, sPlRo 1,938,119

TEMPERATURE ACTUATED CIRCUIT CLOSING DEVICE Filed Nov. 30, 1932 Patented Dec. 5, 1933 TEMPERATURE ACTUATED CIRCUIT CLOSING DEVICE Harry Spiro, San Francisco, Calif.

Application November 30, 1932 Serial No. 645,018

3 Claims. (Cl. 200-442) This invention relates to a temperature actuated circuit closing mechanism intended for use in conjunction with automatic fire alarm soundingor signalling devices, and the like, and particularly to a modified or improved form of the mechanism shown in my former Patent Number 1,868,925, entitled ,Temperature actuated circuit closing device issued July 26th, 1932.

The temperature actuated circuit'closing device disclosed in Patent Number 1,868,925, briefly stated, comprises a two strand cable of any desired length in which the strands are insulated with relation to each other. Insulation is removed from the cable. at spaced intervals to expose the strands and tubular sleeves are inserted in the cables at the points where the insulation has been removed. Each sleeve supports a circuit closing device which is normally held out of contact with the exposed portions of the strands by-means of a fusible metal, hence if the metal is subjected to a sufilciently high temperature produced by a fire or the like, the metal will melt or fuse, the circuit closing device is released and as such will engage the exposed portions of the wires and automatically close a circuit which will cause the sounding of an alarm, etc.

The device disclosed in the patent just re-- ferred to is simple,,cheap to manufacture, it is easy to install and fuctions to perfection, but it lacks one function which is desirable in certain installations, to-Wit, that of opening the circuit or of automatically restoring itself for further operation afterv a fire has been extinguished.

The desirability of a self-restoring device will be better understood when .it is considered that cables provided with circuit closing devices of the character describedare often strung'between the joists and between the wall spaces of buildings, and other places which are not readily accessible, hence if the devices are not self-restoring it is necessary, after a fire has been extinguished, to pull out one or more of the cables to reset or re place one or more of the circuit closing devices as one or more may have func- The object of the present invention is to generally improve and simplify the construction and operation of circuit closing devices of the character described, and in particular to provide a circuit closing device which, is self-restoring when a fire has been extinguished.

An improved form of the circuitclosing mechanism is shown by way of illustration in the accompanying drawing, in -which- Fig. 1 is a perspective view of a cable showing a plurality of circuit closing devices attached thereto.

Fig. 2 is a perspective view of the circuit closing device.

Fig. 3 is an enlarged crosssection taken on line III- III of Fig. 5.

Fig. lis a plan view of the circuit closing deas vice shown in Fig. 2.

Fig. 5 is a longitudinal section taken on line V-V of Fig. 3, showing the circuit closing device attached to a cable.

Fig. 6 is a section similar to Fig. 5 showing a modified form of the circuit closing device.

Fig. 7-is a cross section taken on line. VII-VII of Fig. 6.

Fig. 8 is a longitudinal section showing another modified form of the circuit closing. device.'76

Fig. 9 is a cross section showing the device of Fig. 8 applied to a cable.

Fig. 10 is a diagrammatic view showingthe cable connected with a source of current supply, said view also showing one of the circuit clos-. ing devices on the cable. I

The circuit closing device forming the subject matter of e the present application is of the thermostatic type, and more specifically stated consists of two strips of metal, or other material having varying coefiicient of expansion. The two strips of metal, or other material, when secured with relation to each other and having different coefiicient of expansion will flex or bend' in one direction or the other when subj ected to temperature variations, and this principle is relied upon in the structure herein disclosed.

In Figs. 2 to 5, inclusive, a circuit closing device is shown which is constructed of two sheets of metal soldered, riveted, or otherwise secured with relation to each other. The plates or strips forming the metal have a shape substantially such .as shown in- Fig. 2, one section 100 of metal being indicated at 2 and the other at 3. The upper central portion is out along the lines indicated at 4, 5'and 6 to form a flexible tongue 1 3 and 5, which is adapted to move into engage- 11 0 I to sumcient temperature.

ends as indicated at 14, see Fig. 5.

ment with the strands 9 and 10 of the cable generally indicated at A.

Thiscable may be'madeof any suitable length and a number of circuit closing devices will be applied thereto, as indicated at B see Fig. 1. A two strand cable is employed, the strands being indicated'at 9 and l0.- These strands are separated and are embedded in insulating material,

such as shown at 11, at suitable intervals; for

- instance, approximately every foot'or so. The

insulating material is removed from the cable, as indicated at 12, that is, just suhicient insulating material is removed to expose theupper surfaces of the wire strands 9 and 10. The

circuit closing'device is then applied and secured in position so as to cover the portion of the cable from which the insulation has been removed, and in this position the free end of the tongue 6 carrying the circuit closing memberS will engage with the strands when subjected The deviceshovvn in Fig. 2 may be referred to as "a bi-metallic sleeve 1 as it is sleeve-likein shape when appli d, and it furthermore is con structed or" two superposed sheets of metal or the like, such as indicated at-2 and S. 'In actual operation the superposed sheets of metal 2 and S are pressed into a substantially channel-shape, as shown in Fig. 2, and a thermostat tongue is then out, After the insulation has been removed from the cable at suitably'spaced intervals, the channel-shaped sleeves are applied and bent around the cable as shown inFig. 3, and the sleeves may befurther secured by crimping the ner of securing thesleeves, together with the -tions of the thermostat arms or tongues carried thereby, is 'exceedinglysimple and one after another can be rapidly applied either byhand or machine operation; -'It is, however, essential that they be properly positioned with relationto the exposed portions of the strands 9 and 10 so that the contact'bar or memberfil carried by the free end of the tongue will engage the exposed porstrands when a circuit is to be closed.

Thecircuit closing device maybe employed for any suitable purpose, but it is particularly intended for sounding an alarm or giving a signal in case of a fire. Cables of this character are strung throughout a building, a warehouse, or whatever, the case may be. be connected with a battery 15, or any other suitable source of current supply, and 'in the circuit will be placed a bell 16 or any other alarm sounding or signalling device. If ,a fire is started, the temperature in the immediate vicinity will rapidly increase and tongue or arm 6 will bend inwardly so as to, bring the congradually return to normal position. they are self-restoring after a fire has been extact member 8 in engagement with the exposed portions'of the strands. The moment a contact is made a circuit is closed through the battery and the alarm, mechanism 16 and an alarm will thus be sounded, and if the fire is successfully extinguished, the temperature will gradu ally drop or return to normal and the tongue or tongues on the circuit closing devices will Hence,

tinguished and the circuit through the alarm mechanism is thusautcmatically broken. This is an obvious, advantage when-"comparison is made with my former patent referredto, as it does not require re-setting' of the. circuit closing} devices as previously described,

This man- I All cables will In Figs. 2 to 5, a circuit closing device has been disclosed which is constructed entirely of a bi-metallic sleeve. This, however, is not essen tial as the sleeve itself maybe made of any ordinary metal, or other suitable material. The

movable tongue or arm, however, must be made of'bi-metallic' material as it is the bi-metallic 'material which insures movement of the arm.

In Figs. 6 and 7 a. sleeve 13 is disclosed. This may be made of any ordinary metal or other suitable material, but the tongue or arm indicated at 19, is constructed of a bi-metallic strip. The free" end is adapted to move with relation'lto the exposed strands to close a circuit therethrough but the other end is riveted,

soldered, welded, or otherwise secured to the sleeve as, indicated at 20.

In Figs. 8 and 9, a sleeve is employed which is made in two sections, such as indicated at 21 and 22. The upper section 22 is made ofa bimetallic materialandthe movable arm or tongue 23 is formed integral therewith in a manner;

similar to thatillustrated in Fig. 2. The lower half of the sleeve indicated atj21 may be'constructed of any ordinary material similar to the sleeve shown at 18 in Fig. 6. The sleeve 22 is first applied to the cable and then the sleeve 21, and as this is' be'nt over the sides of the sleeve section 22 and the ends of both sleeves, are crimped to the cable'in amanner' similar' to" that shown at '14 in Fig. 5, the two sections will" be rapidly secured. a

Plainly speaking, the sleeve maybe made" throughout of a bi-me'tallic material, as shown" in Figs. '2 to 5; it ma be made partiallyof oi-metallic material and partiallyof other material as shown in Figs; Band" 9', or it may be" iii constructed-entirely of other material as shown" in this marmer it will be heated just as rapidly as the sleeve and part'of the heat "will also'b'e derived by conduction' from the sleeve. It will thus be sensitive and willact rapidly when the temperature increases. The contact'm'ember 8' should preferably be sharp so as'to cut'into the surface of the exposed strands9 and 10-,ther'eby' insuring a good contact; that is; acable provided with circuit closing devices of this char acter may be installed for monthsor years be-.

fore a fire may .occur and during' that period the exposedjsurfaces of the strands may become more or less oxidized or coated, henceif the contact member is sharp such-coating will be cut through and a goodcontact insured.

While certain features of, thepresent inven-. tion are more or less specifically describedfl wish it understood that various changes may be"- resorted to within the scope ,ofQtheappended;

claims. Similarly, that'the materials and finish of the several parts employed maybe such as the manufacturermay decide, or'varying condi tions or uses may demand: I

Having thus described my invention, what r claim and desiretose'cure by Letters Patent is; "1. An electric. current carryingflexible cable comprising a" pair of conductors eneiossmin sulating material and insulated with relation to each other, a portion or said insulating material being removed to expose the conductors, an

elongated sleeve enclosing the exposed portions of the conductors, said sleeve being constructed of two layers of material having different coeflicient of expansion, a thermostatic arm forming a portion of the sleeve and formed integral therewith, one end of the arm being free to move inwardly toward the exposed portions of the conductors when subjected to a predetermined temperature, and a contact member on the free end of the thermostatic arm and engageable with the conductors when the thermostatic arm is actuated.

2. An electric current carrying flexible cable comprising a pair of conductors enclosed in insulating material and insulated with relation to each other, a portion of said insulating material being removed to expose the conductors, an

elongated sleeve enclosing the exposed portions of the conductors, said sleeve being constructed of two layers of material having different coeflicient of expansion, a thermostatic arm forming a portion of the sleeve and formed integral therewith, one end of the arm being free to move inwardly toward the exposed portions 01 the conductors when subjected to a predetermined temperature, and a contact member on the free end of, the thermostatic arm and engageable with the conductors when the thermostatic arm is actuated, said contact member and forming a closure therefor, means securing one end of the arm to the sleeve, said means leaving the other end of the arm free, and a contact member on the free end of the arm and engageable with the exposed portions of the conductors to close an electric circuit through the conductors when the arm is subjected to a predetermined temperature.

HARRY SPIRO.

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