US1348338A - Circuit-closing thermostat - Google Patents

Description

J. N. VANDEGRIFT. CIRCUIT CLOISING THERMOSTAT.

APPLICATION FILED FEB. 17, 1919.

1,348,338, Patented Aug. 3, 1920.

fig 4. 4g 15 w mo v UNITED STATES PATENT. OFFICE.

CIRCUIT-CLOSING THERMOSTAT.

Specification of Letters Patent.

Patented Aug. 3, 1920.

Application filed February 17, 1919. Serial m. 277,434..

To all whom it may concern:

Be it known that I, JAMES resident of Red Bank, county of Monmouth, and State of New Jersey, have invented certain new and useful Improvements in Circuit-Closing Thermostats, of which the following is a specification.

This invention relates generally to circuit closing thermostats, with more particular reference to that type of device in which the melting of a readily fusible alloy results in the deposit of the latter in such place and manner as to electrically connect the two wires of a normally open circuit. The device of my invention may doubtless serve many useful purposes, but I have especially in mind a thermal circuit closing device for employment in connection with automatic fire-alarm systems.

The principal objects of the present invention are, first, the provision of a device which may be applied after installation of the wiring system at any desired point, merely requiring removal of minor portions of the insulation and without cutting the wires or the necessity of providing terminals or terminal binding posts; second, the provision of a device which is exceedingly small in size and which may therefore be easily concealed and not impair the general sightliness of the decorations of a room or chamber; third, the provision of a device which is practically dust-proofit being well known that the accumulation of dust to a certain degree prevents the establishment of electrlcal connection and this without losing sight of the idea of simplicity of construction and application, and,'fourth, the utmost simplicit of construction compatible with dependa ility of operation and, therefore, inexpensiveness.

My invention will be more readily understood by reference to the accompanying drawings, forming a part of this specification, in which- I Figure 1 is a side elevation of a practical and convenient embodiment of the invention;

Fig. 2 is a top plan view thereof;

Fig. 3 is a vertical section, taken substantially on the line 3-3 of Fig. 2;

Fig. 4 is a transverse vertical section, taken substantially on the line of Fig. 1.

N. VANDE-' omr'r, a citizen of the United States, and a Fig. is a detail view of the two parts of the casing in unassembled condition;

F1 6 1s a view similar to Fig. 2 with the fusib e plug or disk and the outer retaining shell or cap removed.

Fig. 7 is a' view similar to Fig. 1 of a modified form of the device;

F g. 8 is a plan view of the same, and

Fig. 9 1s a transverse vertical section taken substantially on the line 9--9 of Fig. 7

Referring now tothe drawings in detail, a and b designate the insulated wires of an ordinary electric circuit, which may be one of any number of similar circuits, from the same or different sources of electric energy, leading through various parts, sections or rooms of a building, and having the usual connections in a common annunciator or separate annunciators, suitably located, to simultaneously sound an alarm and indicate the location of trouble in the usual and well-known manner under conditions as hereinafter explained. It is to be understood that the circuit is normally open.

The circuit closing thermostat of my invention comprises a preferably circular and slightly tapering sheet-metal shell 11 having oppositely-disposed pairs of notches 12 and 13 in the lower edge or rim thereof adapted to receive and snugly contain the insulated wires aand b. I have shown a cup-shaped shell or bottom cap 14 adapted to be telescoped on the lower end of the shell 11 and close the same, the upper edge or rim of the shell 14 being provided with notches 12 and 13' which correspond with the notches 12 and 13 in the shell 11, whereby when the two parts 11 and 14 are assembled, as shown in the drawin s, a thimble-shaped casing is provided whic is apertured for the passage therethrough of the wires a and 6. Prior to the assembly of these parts on the wires,

the insulation is cut from the latter for a distance slightly less than the diameter of the shell 11 at its lower end, whereby the edges of the notches in the parts 11 and 14, when assembled. will engage the insulation and not come in contact with the bare wires.

A disk, plug or cap 15, the same being formed from a more'or less readily fusible alloy, is adapted to fit snugly within the upper and larger end of the shell 11. Alloys compounded for the purpose of fusion at comparatively low abnormal temperatures a e 1 911 kn n in this art to necessitate detailed description here. Sufiice to say, for the purposes of this description, that upon the raising of the temperature in the immediate vicinity of the device above what ma be termed the maximum normal, this disk 15 will be melted and the molten fluid drop or flow to the bottom of the chamber within the assembled parts 11 and 14, thus establishing an electrical connection between the exposed wires therein and closing the circ.uitwith result as herein-before set forth.

I have shown the cup-shaped bottom cap or shell 14 provided with upwardly-projecting and preferably integral arms 16 16 which extend above the upper rim of the shell 11, whereby the extremities of said arms may be bent over to engage the disk 15 and retain the same in place. It will be apparent that these arms 16 16 serve the two-fold purpose of retaining the disk 15 in place in the shell 11 and the sealing-cap 14 in place on the lower end ofsaid shell.

In Figs. 7, 8 and 9, I have shown the shell 11 provided with lugs 17 17 projecting laterally from the lower edge or rim thereof,- and the sealing cup orshell 14' rovided with corresponding lugs 18 18 on the upper edge or rim thereof, the two parts being adapted to be secured together by small bolts 19 19 passing through the superposed lugs whereby the same are clamped together by means of the nuts 20 20. In this construction, I do not provide the cap of shell 14' with the upwardly-projecting arms, but form the shell 11' with lugs or ears 21 21 on the upper edge or rim thereof, adapted to be bent over the disk 15' of fusible material to retain the same in place.

In use, after the wiring has been installed, and the locations for the thermostats having been selected, the insulation is cut from the wires in the usual manner at these points, care being taken to expose the wires only throughout the desired distances, whereupon the shell 11 (or 11') is first properly positioned, the disk 15 (or 15') having been mounted therein, then the cap 14 (or 14') is assembledtherewith in the manner hereinbefore described, and either the ends of the arms 16 16 or the lugs or cars 21 21-as the case may be-bent downwardly to engage said disk, whereupon the installationfor this articular station-is complete.

W ile I have referred to the wires a and 6 as providing a normally open circuit, it

is well known that automatic fire-alarm systems. as a rule, include an ordinary closed supervising circuit between battery terminals of which one of these wires forms a part, the other wire connecting the firealarm gongs and annunciators, remaining a part of the circuit which is normally open until said wire is connected with the firstmentioned wire by the fused alloy of the thermostat.

Many modifications of minor details of my improved circuit closing thermostat will doubtless readily suggest themselves to those skilled in the art to which it appertains, and I therefore do not desire to limit my invention to the specific construction herein shown and described.

I claim:

1. In a device of the character described, the combination of a cup-shaped receptacle through which the insulated wires of an electric cir'cuit'are adapted to be passed with a minor portion'of the insulation on each wire within said receptacle removed, and a body of readily fusible metallic material mounted and retained above the de-insulated portions of said wires.

2. In a device of the character described, the combination of two separable members assembled to form a cup-shaped apertured shell through the lower part of which the insulated wires of an electric circuit are adapted to be passed with a minor portion of the insulation on each wire within said shell removed, and abody of readily fusible metallic material mounted and retained in said shell above the de-insulated portions of said wires. n

3. In a device of the character described, the combination of two separable and interfitting members assembled in telescopic arrangement to form a cup-shaped apertured shell through the lower part of which the insulated wires of an electric circuit are adapted to be passed with a minor portion of the insulation on each wire within said shell removed, and a body of readily fusible metallic materialmounted and retained in said shell above the de-insulated portions of said wires.

4. In a device of the character described, the combination of two separable members assembled to form a cup-shaped apertured shell through the lower part of which the insulated wires of an electric circuit are adapted to be passed with a minor portion of the insulation on each wire within said shell removed, and a body of readily fusible metallic material in said shell above the de-insulated portions of said wires, one of said members being provided with means for removably retaining said body in place.

5. In a device of the character described, the combination of two separable members assembled to form a cup-shaped apertured shell through the lower part of which the insulated wires of an electric circuit are adapted to be passed with a minor portion ofthe insulation on each wire within said shell removed, a body of readily fusible metallic material mounted and retained in said shell above the de-insulated portions of said wires, and means for detachably secursaid members together in assembled con- 1 ion.

6. In a device of the character described, the combination of two separable members assembled, to form a cup-shaped apertured.

shell through the lower part of which the insulated wires of an electric circuit are adapted to be passed with a minor portion of the insulation on each wire within said shell removed, a body of readily fusible metallic material in said shell above the de-insulated portions of said wires, and means which at the same time secures said members together in assembled condition and retains said body in place.

7. In a device of the character described, the combination of an annular shell, a cupshaped shell having telescopic connection therewith to close one end thereof, the edges of said elements being provided with registering notches adapted to form wire-containing apertures when said elements are assembled, a disk of readily fusible metallic material fitting within the open end of said annular shell, and means on said cup-shaped shell for retaining said disk in place.

8. In a device of the character described, the combination of an annular shell, a cupshaped shell having telescopic connection therewith to close one end thereof, the edges of saidelements being provided with registering notches adapted to form wire-containing apertures when said elements are assembled, and a disk of readily fusible metallic material fitting within the open end of said annular shell, said cup-shaped shell being provided with arms projecting above the upper edge of said annular shell and adapted to be bent over said edge to retain said disk in place and said shells in assembled condition.

9. In a device of the character described, the combination, with contiguously arranged insulated wires of an electric circuit, of a cup-shaped receptacle through which said wires pass and within which a minor portion of the insulation has been removed from each wire, and a body of readily fusible metallic material mounted and retained above the de-insulated portions of said wires.

10. In a device of the character described, the combination, with the contiguouslyarranged insulated wires of an electric circuit,

of two members assembled to form a cupshaped apertured shell through the lower part of which said wires pass and within which a minor portion of the insulation has been removed from each wire, and a body of readily fusible metallic material mounted in said shell above the de-insulated portions of said wires.

In testimony of the foregoing, I have hereunto set my hand in the presence of two witnesses.

' JAMES N. VANDEGRIFT. Witnesses:

ELEANOR C. KELLY, FRED H. BOWERSOCK.

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