US1719672A - Automatic fire alarm - Google Patents

Description

. July 2, 1929. F. F. RANDOLPH AUTOMATIC FIRE ALARM Filed April 6, 1927 gmnmto'o F'Z'PandoZ uh:

Patented July A 2 1929.

' 1,719,672. 'JUNITTEDYSTATES. PATENT. OFFICE.

FIt EID r. RANDOLPH, or FISKDALE, MASSACHUSETTS.

AUTOMATIC FIRE ALARM.

Application filed April 6,

This invention relates to alarm mechanism and provides for the automatic giving of warning in the event of fire or the abnormal rise of temperature from any cause.

The invention contemplates an electric circuit and a signaling device therein, such as an electric bell, which, when the circuit is closed, operates to give warning of impending danger from fire.

The invention consists of a thermally controlled electric switch, included in the alarm circuit to automatically close it when a predetermined rise in temperature has been reached.

Vi/hile the drawings illustrate a preferred embodiment of the invention, it is to be understood that in adapting the means to meet specific needs and requirements, the design may be varied and such other changes in the minor details of construction may be resorted to within the scope of the invention as claimed without departing from the spirit thereof.

For a full understanding of the invention and the merits thereof, reference is to be had to the following description and the drawings hereto attached, in which,-

Figure 1 is a diagrammatic view, illustrative of the invention.

Figure 2 is an elevational View of the circuit closing switch.

Figure 3 is a horizontal sectional view on the line 3- -3 of Figure 2.

Figure 4: is a perspective view of the fuse.

Corresponding and like parts are referred to in the following description and designated in the several views of the drawings by like reference characters.

Referring to Figure 1 the letter A designates the alarm circuit, B a plurality of alarm devices, such as electric bells included in the circuit, and C switches or circuit closing clevices, which are automatic in operation for completing the circuit under abnormal conditions and effecting the sounding of an alarm. It is to be understood that the switch or circuit closing device is located at the place to be safeguarded, and the alarm devices may be arranged at any determinate point for attracting attention when the alarm circuit is closed. Obviously, the alarm devices may be of the visual or audible type as required.

The circuit closing device C includes a box 1 for receiving and supporting the coacting parts. This box is adapted to be located at any determinate point, and is fixed to a Wall 1927. Serial No. 181,504.

or other suitable support. A fixed contact 2 is attached to a wall of the box, such as the back thereof, and comprises spaced jaws 3 adapted to receive the element 4 of the movable contact. The jaws 3 are resilient and frictionally engage the element 4, thereby assuring a closing of the circuit when the movable contact 41 is released. A bracket 5 attached to the back of the box 1 is formed with spaced ears 6, between which an arm 7 is pivoted, and which carries the movable contact 4. An arm 8 projects from the arm 7, and extends through a vertically disposed slot 9 formed in a wall of the box. The projecting end of the arm 8 is provided with a weight 10. Brackets 11 are attached to the outer side of the box 1 adjacent to and upon opposite sides of the slot 9, and their horizontal portions receive clamp screws 12 which serve to secure the fuse to the brackets.

The fuse consists of end clips 13 and a connecting wire 14 of fusible metal of a nature to melt at a relatively low temperature. When the fuse is in position the clips 13 rest upon the horizontal portions of the brackets 11, and are secured thereto by means of the clamp screws 12. The fusible element or wire 14 extends across the space formed between the brackets 11 and engages under the arm 8, and supports the same, as indicated most clearly in Figure 2. When the arm 8 is thus supported the movable contact element 4 is held away from the fixed contact 2, but in the event of the element 14: fusing by an abnormal rise in' the temperature the weighted end of the arm 8, being no longer supported, gravitates, with the result that the contact 4 engages the contact 2 and closes the alarm circuit and gives warning of impending danger.

Lead wires 15 from thealarm circuit, are con nected to plates 16 applied to the back of the boxl and these plates in turn are electrically connected to the parts 2 and 5 by means of bolts, or other suitable fastening means, thereby establishing an electric connection between the lead wires and the contact elements. The alarm circuit may contain. any number of alarm devices and circuit closers according to the capacity and extent of the system.

Having thus described the invention, I claimf An electric alarm circuit closer comprising a box provided in a side wall with a vertical slot, at fixed contact within the box including resilient jaws, an arm pivoted within the box adapted to besecured to the brackets and normally support the Weighted armaind hold the pivoted arm elevated With the contact carried 1 thereby away from the fixed contact.

In testimony whereof I aflix my signature.

FRED F. RANDOLPH. [14.8.]

Images