US2488281A - Fire alarm switch - Google Patents

Description

Nov. l5, 1949 J. E. FoRMANx-:K

FIRE ALARM SWITCH Filed Jan. 50, 1947 m @y/WM5@ Patented Nov. 15, 1949 UNITED, STAT-'ES A'EENT GFFICE FIRE ALARMSWI-TCH Joseph E.For1nanek,.Britt, Iowa Application January 30, 1947, Serial No. 725,213

1 Claim. l

The present invention relates to a iire alarm switch and it consists in the combinations, constructions and arrangements of parts herein described and claimed.

The invention contemplates the provision of an apparatus including a multiple wafer thermostat adapted to move a lever in response to variations in temperature and a pair of adjustable connections adapted to come into contact with the lever one at a certain selected high temperature and the other at a like selected low temperature.

It is accordingly an object of the invention to provide, in a device of this character, a fire and temperature alarm having means for sounding an alarm at a certain high and at a certain low preselected temperture.

A further object of the invention is the provision of a single thermostat for accomplishing ie above-mentioned object.

A further object of the invention is the provision of a device of this character having a minimum number of parts and which will be inexpensive to manufacture yet will be reliable in operation and easily adjusted.

A further object of the invention is the provision of a simple means whereby the aforementioned high and low temperature contacts may be readily and minutely adjusted.

Other and further objects of the invention will become apparent from a reading of the following specification taken in conjunction with the appended drawings, in which:

Figure 1 is a plan View of an embodiment of the invention,

Figure 2 is an end elevational View of the device shown in Figure 1, and

Figure 3 is a side elevational view of the device shown in Figure l together with a schematic showing of the circuit employed,

Referring more particularly to the drawings, there is shown therein a frame having a bottom I ll, sides II and I2 and top end pieces I3 and I. A brace member I5 is mounted centrally between the sides II and I2 and is preferably formed of bakelite or other dielectric material. A second brace member I6 is likewise mounted adjacent to end I3 of the frame and carries centrally thereof a stud I'! to which is aixed a multiple wafer type thermostat IB which is adapted to bear against the lower end I9 of a bell crank lever which is pivotally mounted in the brace I5 as indicated at 20 and Whose upper end 2I projects substantially vertically above f' 2 the top of the frame. A conical spring 22 is centrally mounted upon the brace I5 and has its smaller end in contact with the lower end of the bell crank lever.

The end piece I3 is formed with an upwardly projecting ear 23 in which is threaded a screw having an operating handle 25 and the end piece I4 is provided with a like ear 26 in which is threaded a screw 2l having an operating handie Eil. The stud I'I is electrically connected with one end of a circuit as indicated at 29 and the frame is grounded with the other end of the circuit as indicated at 30.

In operation it will be apparent that the screws Se and 2l may be adjusted to make contact with the upper end 2l of the bell crank lever 2li for preselected high and low temperatures, respectively. Upon a rise in temperature the thermostat I8 will expand moving the lower end I9 of the bell crank lever 253 against the action of the spring 22 thereby causing eventually contact to be made between the screw 2l! and the upper end 2I of the bell crank lever 2Q. This will complete an electrical circuit including the screw 24', the entire bell crank lever 20, the thermostat I8, the stud I'I, the connector 29, the source of power 3|, an alarm bell 32, and the frame (through contact .36) and thence back to the screw 24. This will complete a circuit through the alarm 32, as above stated, and thus sound the same when a preselected high temperature has been reached.

It will be apparent then, that upon a preselected low temperature having been reached, the thermostat I8 will have contracted sufficiently for the spring 22 to urge the bell crank lever 20 into contact with the screw 2l whereupon the circuit above mentioned with the exception that the screw 2l is now included instead of the screw 24 will be completed and the alarm 32 sounded.

While but one form of the invention has been shown and described herein, it will be readily apparent to those skilled in the art that many minor modifications may be made therein without departing from the spirit of the invention or the scope of the appended claim.

What is claimed is:

A thermostatic device adapted to close an electric circuit comprising a metal frame having top, bottom, end pieces, projections having threaded openings and extending upwardly from said end pieces, adjusting screws threaded through said openings and serving as contacts, the frame being adapted to carry a current, an insulating member secured within the frame to the top and bottom pieces, a second insulating member disposed in the frame adjacent one end thereof, a wafer type thermostatic element anchored to the second insulating member, a Contact terminal engaging with the element and adapted to have a wire connected with it, a lever pivoted on the rst mentioned member and having a lower arm extending into engagement with the thermostatic element and an upper arm extending upwardly from the top of the frame to between the ends of said contact screws for engaging either of the same depending upon the contraction and expansion of the thermostatic element, and biasing means on the first mentioned insulating member engaging the lower arm of the lever urging the same into engagement with the thermostatic element.

JOSEPH E. FORMANEK.

REFERENCES CITED The following references are of record in the 111e of this patent:

UNITED STATES PATENTS Number Name Date 993,168 Huberman May 23, 1911 1,066,731 Jaynes July 8, 1913 1,225,437 Hammond May 8, 1917 1,474,001 Pavment Nov. 13, 1923 1,824,933 Schultz Sept. 29, 1931 1,891,994 Machacek Dec. 27, 1932 1,922,580 Gekler Aug. 15, 1933 1,922,898 Mockelmann Aug. 15, 1933 1,933,083 Ackerman Oct. 31, 1933

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