US207139A - Improvement in thermostats for fire-alarms - Google Patents

Description

UNITED STATES PATENTYOFFIGE.

GEORGE S. SHUTE, OF BOSTON, MASSACHUSETTS.

I'MPAROVEMENT IN T-I-iERMOST-ATS FOR FIRE-ALARMS.

Specification forming part of Letters Patent No. 207,139, dated August 20, 187 application lileu' July 30, 1877.

To all whom it may concern:

Be it known that I, GEORGE S. SHUTE, of Boston, in the county of Sufl'olk and State of Massachusetts, have invented an Improvement in Thermostatic Fire-Alarms, of which the following is a specification This invention relates to a fire-alarm operated by heat and the invention consists in the combination, within a case provided with two apartments, one of which is more exposed to the influence of the atmosphere than the other, of two parallel bars or springs, each composed of two metals of varying degrees of expansibility, whereby, when the temperature of the room in which the case is situated is raised suddenly above a certain degree, as in case of fire, the bar or spring in the most exposed apartment will be deflected more than the other, and cause a finger or circuit-closer supported and carried by one of the springs or bars to come in contact with the other spring or bar, thereby closing an electric circuit and setting in operation an alarm, either in the same building or at a distance.

If both springs or bars are acted upon gradually, they will move together, and the circuit will not be closed until at or abovea certain temperature, at which the springs'may be adjusted to close as their ends move in the arc of a circle.

Figure l is a plan view of the case with the lid open; Fig. 2, a side view of the case at the side of the most exposed apartment Fig. 3, a longitudinal section on the line a: m, Fig. 1; Figs. 4 and 5, end views of the case; and Fl 0 a 6, a side view of one of the springs or bars disconnected or broken off, and laid on the inner side of the cover of the opened case of Fig. l.

The case a, made of metal or other suitable material, is provided with a cover, b,and with a partition, 0, by which to divide the case into two apartments, (1 c;

"The apartment d is supplied with air, chiefly through the preferably-grated opening f and the'small opening y, made for the reception of the circuit-closing. finger h, attached to the spring a, which is supported in a block of wood or rubber, j, in the most exposed apartment 0, which has its side opened or exposed for the passage of air and heat, as at It, and its ends opened, as at l and m. The spring a in apartent d is connected with a block, 10, of wood or'rubber. This springer bar a will be so held that by means of a screw, 1', arranged to press against one side thereof, the outer end, 2, of thespringorbarmaybe causedto assume aposition nearer to or farther from the downwardlybent end 3 of the finger h, as seen in dotted lines, Fig. 4.

In practice, the end 3 of the finger will rest at about one-eightlipf an inch from the end of the spring a but this distance may be more or less, as it is desired to close the circuit slower or faster, owing to a sudden increase of tem-.

perature, as by fire.

Each spring has attached to its side a strip of a difl'erent metal, as at 4, so that the two metals composing each spring have different degrees of cxpansibilit'y under the action of heat.

If the room in which the case is located is quickly heated to a dangerous degree, the atmosphere,eutering the most exposed apartment 0 quickly and the least exposed apartment d slowly, causes the spring 6 to be deflected faster and to a greater extent than the spring a, and consequently the end 3 of the finger h, carried bythe spring or bar 1', will be brought against the end of spring a, and will complete the electric circuit, the wires 5 6, connected with the springs or bars, being. properly joined on circuit, so as to sound an y usual alarm near or at any desired distance or location.

This invention forms a very simple and cheap alarm, which may be placed in any building or room, and be connected with an alarm or signal to be sounded, and which mayalso designate the room or the house, &c., if councctcd on circuit with headquarters of firebrigade.

In practice, the springs n "i are tested before being placed in the case, so as to select for each case two springs of like degrees of expansibility.

1 claim- A box or case having two apartments, one:

2 I sense springs or bars of difi'erent degrees of expan- In testimony whereef 3 ave signed my name sibility, one inclosed in each of, the apartto this specification in the presence of two subinents, in combination with a circuit-closing scribing witnesses. finger, connected directly with, and supported v and, carried. by, one of the springs or bars, GEORGE S. SHUTE. whereby,- when the more exposed bar is moved by heat monerapidly than the other, the finger Witnesses:

will connect the two bars to close an electric CHARLES Gums, circuit to give an alarm, substantially as set HENRY T. FITIS. forth.

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