USRE8075E - Improvement in electric and thermostatic fire-alarms - Google Patents

Description

G. s. SHUTEQ Electric and Thermostatic Pire-Alarm.

Reissued Feb. 5,1878.

IIIX/EIHEIY.

" UNITED STATES PAT N O FICE.-

GEORGE s.' snUtrE, ornos'ron, MASSACHUSETTS.

IMPROVEMENT m ELEc-rmc AND TH ERMOSTATI'C FIRE-ALARMS- Specification forming pains: Letters Patent N0.'150,090, dated April 21, 1514; Reissue Nit 8,076, time 7 L February 5, 1878; application file'd December 27, 1877.

- in afire-alarminstrument, of insulated springs,

each constructed of metals of difi'erent degrees of expansibility, arranged in electric circuit with an alarm, with connecting'devices between thesprings, whereby one spring moved more than the other by heat operates such devices to make a metallic connection between itself and the other spring, to throw v into action an electric alarm, the springs under gradual or ordinary changes of temperaturemovin g together and not closing the circuit also, in a fire-alarm instrument, the combination, with thermal bars, of a case divided into two apartments, onefor each bar, one apartment being more exposed than the other to the atmosphere, whereby the bar in the more exposed apartment at sudden or great changes of heat will be moved more than the other-bar in the least exposed apartment, and will thereby operate devices to form a metallic connection between the two bars,and set in action an electric alarm in circuit with. the

are.

Figure 1 represents, in plan, the moving parts of my invention; and Fig. 2 is a section, showing the arrangement of the casein which the devices are held.

Let A and A represent thermal bars,'made in the well-known manner, by uniting two strips .of metal side by side, the metals having difl'erentconstants of expansion. These bars are attached at their outer ends to thecase by means of any suitable device, as B, for instance, Fig. 1. The inner ends of these bars A and A are provided with pins a a, which pass through slots made in the crossarm C, Fig; 1, hung on a pivot, D, which pivot 'has attached to it an arm, R, represented by dotted lines, which has at one of its ends a segment-gear, E, .and at its other end a balance, F. The segmentgear E acts upon a pinion, I, which is attached to the wheel K, having spurs c c, &c.

The metals in the thermal bars A and A are so arranged that in case of expansion or 0011 traction by heat the bars act in' concert togive motion to the cross-arm G, and through it the arm It, segment E,- and wheel K.

- The thermal bars L and L are arranged and supplied with an arm, C, a segment-gear, E, balance F, pinion I, like those described above, and with a wheel, M, having spursb b, 8w

The bars L and L are made lighter than the bars A and A, so that they will be moresensitive to a sudden change of temperature.

I attach to one of the wheelsK or M apointing-hand, S, which, moving over a graduated arc, will indicate the sensible temperature.

The projecting spurs b b and c o are placed at equal spaces around the wheels KM, and so placed with relation the one to the other that at ordinary temperature of "the atmosphere the spur of one wheel, b',.for instance,- will be between two spurs, c c, of the wheel K, touching neither, so that if both wheels revolve equally the spurs of one will not touch the spurs of the other; but in case one wheel revolves. faster than the other, then the spurs of one wheel will come in contact with the spurs of the other, and thus start the electric alarm. v I

. The case a: is arranged as shown in Fig. 2, with an inclosed apartment, T, in which the thermal bars A A are placed; but the other apartment, V, is open to the air at :0, so that in case of fire the rods L L will be first exposed I to heat, and, by expanding more rapidly than the rods or bars A A, cause the spurs of the wheel K to overtake the spurs of the wheel M, andthus make the connection necessary to give the electric alarm through circuit-wires and yet move with firmness when acted upon.

by the least variation of temperature.

The'thermal bars act in the capacity of stead ying-springs' as well as thermostats..

The main/thermal bars AL are assisted in I operating the connecting devices by means of the auxiliary bars A L.

I claim '1. In a fire-alarm instrument,insulatedthermal bars constructed of metals of diflercnt degrees of expansibility, and connecting devices, whereby a circuit may be completed between them, one of such bars being placed in a case and more exposed bar, to throw into. action an.

electric'alm'm, the bars under gradual or ordinary changes of temperature moving together substantially alike without closing the circuit.

2. In a fire-alarm instrument, the combination, with thermal bars, of a case divided to form two apartments, one for. each bar, one apartment being more exposed to the atmosphere than the other, whereby the bar inthe more exposed apartment at sudden or great changes of heat or temperature will be moved more than the other bar in the least exposed apartment, and will thereby operate devices to form ametallic connection between the two bars in the difl'erent apartments, and set in action an'electricalarm in circuit with the bars, substantially as described. t.

3. A thermostatic firelarm case divided into two apartments, one of which is more open to the action of the atmosphere than the other, whereby one apartmentin a given time may receive a greater amount of heat than the other, to operate thermal bars in such apartments one more rapidly thanthe other.

.4. 'l he' combination of the thermal bar A, the cross-head C, and the thermal bar A, all arranged to operate together, substantially as described, and for the purpose set forth.

5. The combination of the thermostat A A, the circuit-closer b b c c, and the thermostat L L, one series of thethermostats beingplaced in an inclosed and the other in an exposed space, all operating together, substantially as described, and-for the purpose set forth.

GEORGE s. sHUTE Witnesses:

GEo. W.- GREGORY. W. PRATT.

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