US2642511A - Thermal-sensitive actuator for fire alarms - Google Patents

Description

June 16, 1953 H. A. RIKE 2,642,511

THERMAL-SENSITIVE ACTUATOR FOR FIRE ALARMS Filed March 21, 1949 Z INVENTOR.

c llfjQad- Ho WAED A. ZKE

A TTOFNEY Patented June 16, 1953 THERMAL-SENSITIVE ACTUATOR FOR FIRE ALARMS Howard A. Bike, Los Angeles, Calif.

Application March 21, 1949, Serial No; 82,632

2 Claims.

Thi invention relates to automatic alarm systems operating in electrical circuits, and it has particular reference to apparatus capable of roducing visible or audible signals when affected by relatively high temperatures, and the principal object of the invention resides in the provision of a sensitized element capable of being compactly housed and installed as an individual unit, as in a small room, or as a part of an alarm system in which a plurality of the units are connected to a central panel or control board.

One of the prime objects of the invention is that of providing a thermal-sensitive element which is compact in form and economically constructed, adaptable to installation at any desired location in such enclosures as hotel rooms, offices, residential buildings, stables, and the like, and being diminutive in size, is completely inconspicuous so that its presence will not mar or impair the appearance of the room.

A still further object of the invention resides in the provision of a device of the character described which is adapted to be installed in a conventional telephone circuit connected to a switchboard or signal panel whereby both visible and audible signals can be transmitted through said circuit, as in a room circuit in hotels, indicating the presence of a fire and its location.

Broadly, the invention contemplates the provision of a device in which is embodied thermalsensitive elements capable of first closing the circuit in which the apparatus is installed and then functioning to produce intermittent signals which are transmitted to the central panel to actuate a lamp or buzzer or produce intermittent sound audible to the operator.

While the foregoing objects are paramount, other and lesser objects will become manifest as the description proceeds, taken in connection with the appended drawings wherein:

Figure 1 illustrates the invention in lateral section, on lines ll of Figure 2, showing the lower circular plate and the bi-metal elements.

Figure 2 is a transverse sectional view, on lines 2--2 of Figure 1, showing the arrangement of the terminals and the bi-metal elements.

Figure 3 is an inverted plan view of the invention showing a plurality of vents grouped at one side.

Figure 4 is a fragmentary sectional view, taken on lines 4-4 of Figure 1, illustrating the laminated construction and showing the intermittent signaling elements in contact.

Figure 5 is another fragmentary sectional view,

on lines 5 5 of Figure 3, showing the ventilating bores communicating with the enclosed intera Figure 7 is a transverse sectional view, on lines 1-! of Figure 6, showing the modified structure and its enclosed terminal connections and the primary bi-metal element, and

Figure 8 diagrammatically illustrates a telephone circuit in which the invention is installed and connected through the circuit to the switchboard. v

Accordingly the invention comprises a circular body member l0 formed preferably of plastic material in a plurality of laminations consisting of a central section II having top and bottom rings [2 and I3 secured together by screws or bolts I4 arranged opposite each other, as apparent in Figures 1, 3 and 6. A terminal I5 is arranged through the central section II and extends through the upper ring [2, as shown in Figure 2, and terminating in the lower ring [3. Nuts [6 and I1 secure the member I5 to the upper ring I2.

Another terminal 18 is arranged through the upper ring I2 and has its inner end terminating in the central section II and has a conductor plate l9 connected at its lower end which extends along a cavity 20 conforming to the contour of the body H), as shown in Figure 1. The plate, however, extends only approximately half-Way the length of the cavity 20 on its outer end. A bi-metal strip 2|, also curved to conform to the cavity 20, extends along the latter from the opposite end and also has a contact point 22 thereon which is engageable with the outer end of the member I9, when the bi-metal strip 2| is cool, to close the circuit between the terminal [8 and a terminal 23 arranged opposite the terminal [5.

The terminal 23 extends from the cavity 20 through the central member I l and into a cavity 24 formed in the lower surface of the member II, as shown in Figure 2. The lower end of .the terminal 23 is adapted to be contacted by the contact point 25 on the free end of a bi-metal strip 26 extending diametrically across the body l0 and having its opposite end attached to the lower end of the terminal [5.

The terminals l5 and [8 are connected into a circuit, as shown in Figure 8, and the bi-metal strip 26 is normally cool and its contact 25 is out of engagement with the terminal 23 maintaining the circuit open. In the presence of heat of a predetermined value the strip 26 will function to close the circuit and heat the coil 21 arranged about the strip 2| causing this member to disengage itself from the end of the plate I!) breaking the circuit. As the strip 2| is cooled it will again close the circuit, repeating this operation intermittently to actuate the signal 28 on the switchboard 29 in Figure 8.

In the modified structure illustrated in Figures 6 and 7 the terminals I8 and 23 are shown connected directly by a conductor 30 arranged in a groove 3| formed in the face of the central section I, and covered by the top ring l2. Thus, when the strip 26 is influenced by heat sufficient to bring about its contact with the terminal 23 such action will close the circuit and produce a constant visible or audible signal or both if desirable.

The invention is shown connected into a conventional telephone circuit in Figure 8. It will become apparent that such connection in the circuit will not affect the normal use thereof while yet aiiording the necessary energy to produce the signal as well as providing a practical means for conducting effecting the alarm from a remote location of a unit in which the invention is embodied.

The transmitter and receiver circuit A is connected to the board 29 through lines 32 and 33, and the signal 28 is energized through these lines and is connected thereto by wires 34 and 35 to each side of the circuit. A wire 36 connects the terminal |8 to the line 33 by a wire 37 while the terminal I5 is connected to the line 32 by 'a wire 38 so that the closing of the circuit through the invention will actuate the signal 28. The unit may or may not be installed near the telephone in order to function properly.

The element 2| is ventilated through a group of spaced, explosion-proof bores 39 through the bottom ring I3 and the central section II. into the cavity 28 embracing the members l9 and 2|. The presence of inflammable gases, therefore, will not necessarily be hazardous, insofar as the member 2| is concerned.

Other modifications and certain changes in design and construction may be resorted to from time to time, by persons versed in the art, without departing from the spirit and intent of the invention or the scope of the appended claims.

What is claimed is:

1. In a device for closing an alarm circuit, an annular body having a pair of terminals arranged therethrough for connection into an electrical circuit, a conductor connected to one of said terminals and extending around a segment of said body and terminating opposite the other terminal, the said conductor comprising a thermally actuated coupling capable of intermittent disengagement to open said circuit, a bi-metal strip connected at one end to said last named terminal and extending diametrically across said body and having a normally disengaged contact on its free end engageable with said conductor to normally close said circuit.

2. In a device for thermally actuating an alarm circuit, an annular body having a passage therethrough, a pair of terminals in said body providing for connecting the same into an electrical circuit, a bi-metal thermal strip having one end connected to one of said terminals and extending across said passage, the free end of said strip having means thereon for engaging a conductor, the said conductor having a thermo-sensitive portion intermittently actuated to provide a connection between said strip and the other of said terminals.

' HOWARD A. RIKE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,653,685 Whittington Dec. 27, 1927 2,209,193 Derby July 23, 1940 2,267,484 Van Houten Dec. 23, 1941 2,439,502 Tate Apr. 13, 1948 2,450,450 Schmidinger Oct. 5, 1948 2,527,767 Schmidt Oct. 31, 1950

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