US333443A - Assigxor to the au - Google Patents

Description

(ModeL) I G. .P. BULEN.

THERMOSTATIG OIRGUIT CLOSER. No. 333,443. Patented Dec. 29. 1885.

' Inventor:

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- 1 UNITED STATES l PATENT OFFICE.

GEORGE F. BULEN, or JERSEY oirr, NEW JERSEY, ASSIGNOR To 'THE an TOMATIC FIRE ALARM AND EXTINGUISHER NEW YORK, N. Y;

COMPANY, (LIMITED,) OF

TH EiiMO-STATIC Cl RCUlT-CLOSER.

SPECIFICATION fonning part of Letters Patent No. 333,443, dated December 29, 1885.

Application filed June 14, 1882. Serial No. 64,144. (Modeh) To all whom it may cofwern:

Be it known that I, GEORGE F. BULEN, a citizen of the United States, and a resident of Jersey City, in the con nty of Hudson and Stateof New Jersey, have invented a new and useful Improvement. in Thermostatic CircuitClosers, of which the following is a specification.

The. object of my invention is to provide a thermostat which will be readily afl'ect'ed by slight changes of temperature, and will by its expansion complete an electric circuit under the influence of any predetermined degree of heat, and to construct the. same in a manner adapted to secure uniformity of action and freedom from the injurious effects due to the continuallymecurring expansio-nand contractraction of the metals of which it is composed.

My invention consists in supporting a thermostatic strip in a novel manner upon a peculiar form of base-plate, and in providing convenient means for covering the same, securing electrical connections therewith, and for supporting a contact-point for completing a circuitby the action of the thermostatic strip.

1n the accompanying drawings, Figure 1 is a plan view of the exterior of a thermostat embodying my improvements. Fig, 2 is a cross-section of the same; and Fig. 3 is a plan showing the working parts of the apparatus, with the top or cover removed.

Referring to these figures, A represents a a metallic base for supporting the various parts of the instrument.

Two binding-screws, a and a, are mounted on opposite sides of the instrui-uent, for convenience in attaching electric conductors thereto. The binding-posta is in electrical connection with the metallic base A, while the post a is insulated therefrom by means of suitable washers, b b, of hard rubber, porce- The thermostatic coil consists of two flat pieces of metal, 0 and 0', (see Figs. 2 and 3,) having different coefiicient's of expansion sccurcly brazed together and formed into an involutc curve. The strip of metal 0. upon the inner side of the curve, is preferably of iron, while the outer strip, 0', is of brass or other material having a coefiicieut' of expansion about twice that of the inner strip, and is also double the thickness of the strip 0. The inner end of the compound strip, which is situated at the origin a of the spiral is supported from the base A, by means ofa screw, D, ex 5 tending through a metallic collar, (i, into anaperture, d. in one side of-which the end a is secured by brazing, soldering, or otherwise. The outer or free end of the curved strip is provided with a contact-point, 6', preferably faced with platinum to prevent corrosion. At; a point beyond the normal position of this coutact-point and directly in the line of the extended curve is supported a contact-stop, against which the point e impinges, as here- 6 in'after explained. when the thermostat is influenced by a snh'icient increase of temperature, This contact-stop consists of a platinum point, 0, supported upon an adjustable screw, E, which is mounted in. a post, E. The post E is insulated from the base A in the same manner as has already been described with reference to the bindingpost a, to which binding-post it is united by a suitable couducting-strip, e. The contact-points e and e are normally separated a short distance from each other, and this distance may be accurately adjusted by means of the movable screw E.

When for any reason the temperature in the building or room containing the thermostat increases or diminishes, the metals composing the section-strips c and c expand or contract accordingly, but in different ratios, and the ratio of expansion of the outer strip being greater than that of the inner, the point 6 will be advanced toward the contact-point a under the influence of an increase of temperature, and will be in like manner withdrawn when the temperature is decreased. It is evident, thcrefore,that the position of the contact-point 0 e may be so adjusted that the circuit will be completed between the points e and a under the influence of any predetermined degree of heat, and hence by including the two points in an electric circuit containing a signaling 5 apparatus an alarm may be automatically actuated thereby in a well-known manner. The terminal wires of such a circuit are shown at W? in Fig. 1, and the apparatus may be united directly therewit-hat the binding-screws a and a; or through the medium of short connecting-wires w w.

Over the top of the instrument and inclosing the thermostatic coil is fitted a cap or cover, H, of thin metal or other suitable material. This cover is preferably convex in shape, and has recesses formed in its edges, as shown, which fit over the lateral lugs supporting the bindingposts a and a'.' The cover is ofspun metal, and is preferably secured in position by being fitted tightly over the edge or rim of the base A, but it; may be secured by screws or other suitable means.

For the purpose of protecting the instrnment, when necessary, from moisture or dust, I provide an outer protector orshie-ld, G,which is supported from the base A by means of a screw, g, which screw is preferably provided with a shoulder, g, to prevent the shield G from coming into contact with the two binding screws (1 and a, and thereby short-circuiting the thermostat.

I claim as my inyentiou- 2- 1. In a thermostat, the combination, substantially ashereinbefore set forth, of athermo static strip, a metallic plate for supporting the same, a collar having an aperture in which said strip is brazed or soldered, a screw extending through said collar into said base and uniting said strip and-collar thereto, and an insulated contact-point applied to the remaining end of said strip.

2. The combination, substantially as hereinbefore set forth, of a, thermostatic strip, a.

metallic base for supporting the same, an insulated screw carried upon said base, an adjnstabie contact-screw extending through a longitudinal opening in said insulated screw into proximity to the end of said strip, and a;

convex spun-metal cover fitting over said strip and contact-point.

3. The combination, substantially as here: inbefore set forth, of a thermostatic strip, a

metallic base-plate, an insulated screw support-ed upon the same having a horizontal opening through the same, a contactpin or,

screw extending through said opening, means for connecting one end of the strip to said base, and a cover, H, for said strip.

4. The combination, substantially as hereinbefore set forth, of a thermostatic strip, the metallic base 21, having lateral iugs, the screws a and a, respectively supported upon said lags, one of which screws is insulated from said base, and a cover, H, for said strip, having recess-es formed in its edges for receiving said lugs.

In testimony whereof I have hereunto sub scribed my name this'9th day of June, A. D. 1882.

scones F. Bonn Witnesses:

CHARLES AaTBRRY, D. W. Eoceoosra

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