US1720793A - Heat-operated alarm - Google Patents

Description

July 16, 1929. v F. A. KUNKLE I HEAT OPERATED ALARM Filed March 5, 1928 INVENTOR ATTORNEYS Patented July 16, 19 29.

UNITED STATES FRANCIS A. KUNKLE, or SLATINGTVON, PENNSYLVANIA.

HEAT-OPERATED A RM.

Application filed March 5,

The invention exemplified by this device is an improven'ient in temperature controlled circuit closers adapted for use in alarm systems. Where it is intended. that an alarm 5 shall be given for example by a bell, light or similar device, operated by electricity on the attainment of certain predetermined temperature; it is customary to cause the electric circuit to be closed by spring operated 10 means released when the critical temperature is reached. One of the objects of my invention is to provide a circuit closer in which the operation is dependent not upon springs but upon the action of gravity alone.

1 Another object of my invention is to pro- ,vi de a circuit closer of simple and rugged construction operating when the critical temperature is reached, by either of two agencies, thus insuring successful operation and reduc- 20 ing the risk of the device failing to operate.

A further. object ofmy invention is to pro-' vide fusible elements which may be readily replaced. and will also respond more certainly to a rise in temperature.

WVith the above and other objects in. View as will hereafterappear, I have illustrated in the accompanying drawing one form which my invention may take. 7 V

Fig. 1 shows a perspective view and. schematic wirin diagram of the circuit closer; V

Fig. 2 is a vertical section on the line22 ofFigl;

Fig. 3 is a fragmentary vertical section on the line 22 showing the contacting weight released and dropped; v

Fig. 4 is a horizontal section on of Fig. 3;

Fig. 5 is a vertical section on the line 55 of Fig. 2 and Fig. 6 is a similar bars in contact.

The device consist-s generally of a support ing member from which is suspended a series of contact members which may be brought into direct contact either bythe melting or burning or an intervening fusible elementor the circuit may be closed between these elements by theaction of an electrically conducting weight which is allowedto fallagainst the members when released from its position by the fusion or combustion of a second heat responsive element. In the embodiment shown in the drawing, a supporting plate 7 of generally circular shape is made of insulating material and adapted to be attached to the lower surface of a ceiling beam or the like. It is the 1.... 4,-4

View with the spring "siliency of themembers.

1928. Serial No. 259,244.

preferred that this base be made of fiber com- 2 position having the desired insulating qualities. A second plate 8 shown .by preference to be square in shape is riveted or otherwise attached to the lower surfaceof the base 7, as indicated at the points 9, 9, thus forming the supporting member. This plate islikewise of insulating material similar to the base 'i'. In the form shown, the fastenings 9 between the base and the plate appear at the corners of the latter.

Midway along the side edges of the plate 8 are rivets 10, 10 which pass through .the plate 8 but not through the base 7 (see Fig. 2). The center of the plate 8 carries a metal loop 11, the ends of which are spread divergently between the plate 8 and base 7 as ,shown in Fig. 2. This loop is of sufiicient size to receive a fusible or inflammable element as will be described later.

The opposite pairs of the four rivets 10 carry the ends 12, 12 of the V-shaped spring bars 13, 1 1, the median portion of each of which'is a flat horizontal extension 15. The ends 12, 12 of the spring'member 13 are bent inwardly above the plate 8 and fastened thereto by means of the rivets 10, 10. From this construction it is evident that the spring bars 13. 14; are disposed atright angles to each other with their median portions 15, 15 normally in contact under the action of the re- The portions 15. 15 can be separated out of contact with each other by'slightly bending the inner spring bar 13.

Electrical contact with. a circuit is provided for each spring bar 13,14 by attaching a conductor 16 under the head of one ofthe rivets 10 of each opposite pair. 'In thisway each spring bar is" connected to the opposite pole of a source of electricalenergy, for example a battery 17 and in series also with signal devices such as the bell 18 and lamp 19..

Alternate means are provided for closing the contact between the spring bars 13 and 14.

The median portions 15, 15 of the latter are separated by a channel shaped piece of celluloid 20. Any suitable material may be used in place of celluloid, it being'merelyimportant that the material be fusible or inflainmable at the critical temperature at which the circuit is desired to be closed. The piece of celluloid is foldedfrom a iiat sheet of material and is of sufficient size so that the ends thereof will extend considerably beyond the meeting surfaces of the sections 15, 15, with the side flanges separating the converging portions of the members 18, 14. In this way the material will respond to ignition which might otherwise be retarded by heat conduction away through- metal strips 13, 14. p

A weight 21 of conducting metal is suspended by means of an eyelet 22 from the loop 11 through a fusible link 23. It is preferred that the fusible link 23 be made of similar material to the member 20 and it is found that such links may readily be cut and shaped from sheet material in the same manner as are the members 20.

'In the operation of the device described above, the base 7 is attached to the structure in the locality where the alarm is to be provided and suitablecircuit connections 16, 17, 18 and 19 arranged either at that locality or in a remote position. The fusible elements 20 and 23 are shaped from appropriate material and assembled with the device. The element 20 is inserted between the portions 15, of the spring bars 13, 14 and thus maintains these members out of contact.

The weight 21 is suspended from the loop 11 by means of the fusible link The de- Vice remains in this position during normal temperatures and until a critical temperature is reached. In the latter event the link 23 will soften and the weight 21 fall into contact with the spring bars 13, 14 as shown in Fig. 3. Thus the electric circuit will be completed from one side of spring bar 13 to one side of spring bar 14 and the signal 18 or 19 brought into operation. The signal will be operated continuously until the weight 21 is separated from the spring bars 13, 14 by hand.

In the event that a critical temperature is reached without the link 23 responding in the manner above indicated, an alternative closing of the circuit is obtained by the melting or burning of the material of which member is composed.

The normal resiliency of the spring bars 4 13 and 14 will therefore bring their median portions 15, 15 into contact resulting in the closing of the electric circuit and the actuation of the alarm.

Again circumstances may exist in which the member 20'is melted or burned away, closing the alarm circuit before the link 23 re- I leases the weight and the latter then becomes an alternative of the member 20.

While the above device shows my preferred form of the invention, many changes may be made in minor details and numerous substitutions of material accomplished within the scope of the invention as set out in the following claims.

I claim:

1. In combination with an alarm circuit, a supporting member, a pair of converging contact strips held by said member, said strips intersecting at their median portions, suspending means on the supporting member above the intersection of said strips, a gravity-operated contact element and a heat rcsponsive element between the contact element and the suspending means.

2. In combination with an alarm circuit, a supporting member, a pair of converging contact strips held by said member, said strips intersecting at their median portions, suspending means on the supporting member above the intersection of said strips, a gravity-operated contact element, a heat responsive element between the contact element and the suspending means, and an inflammable element for holding said median portions of the contact strips out of contact.

3. In 'combintion with an alarm circuit, a supporting member, a pair of V-shaped contact strips held by said member, said strips intersecting at their median portions, suspending means on the supporting member above the intersection of said strips, a gravity operated contact element, a heat responsive link between the contact element and the suspending means, and circuit connections to each contact strip.

4. In combination with an alarm circuit, a supporting member, a pair of V-shaped resilient contact strips held by said member, said strips intersecting at their median portions, and a sheet of inflammable material separating said median portions.

5. In combination with an alarm circuit, a supporting member, a pair of V-shaped resilient contact strips held by said member, said strips intersecting at their median portions, and a sheet of inflammable material separating said median portions, and extendingly outwardly therefrom.

6. In combination with an alarm circuit, a supporting member, a pair of V-shaped resilient contact strips held by said member, said strips intersecting at their median portions, and a sheet of inflammable material bent in channel form to separate the converging portions of thestrips.

7. In combination with an alarm circuit, a supporting member, a pair of V-shaped resilient contact strips held by said member, said strips intersecting at their median portions, heat responsive means for bringing said strips into contact, a contact element and a second heat responsive means for actuating said element to close the circuit through said strips independently of the action of the first said heat responsive means.

In testimony whereof, I affix my s1 gnature.

"FRANCIS A. KUNKLE.

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