US1932783A - Control device for alarm mechanism - Google Patents

Description

Oct. 31, 1933. c. P. HOWARD 1,932,783

CONTROL DEVICE FOR ALARM MECHANISM Filed Oct. 2, 1931 o MQQX? lrcdemv" Patented Oct. 31, 1933 CONTROL DEVICE FOR ALARM MECHANISM Clifton P. Howard, Worcester, Mass., assignor to Rockwood Sprinkler Company of Massachusetts, Worcester, Mass, a corporation of Massachusetts Application October 2, 1931. Serial No. 566,569

4 Claims. (01. 200-142) This invention relates to mechanism designed to sound an alarm on the occurrence of a rise in temperature of the surrounding atmosphere above a predetermined point. The invention is par- 5 ticularly directed to the temperature responsive device by which the alarm mechanism is controlled.

It is the object of my invention to provide an improved control device which will occupy very l slight head room and in which all movable and contact parts are efiectively covered and pro tected.

My invention further relates to arrangements and combinations of parts which will be herein- 15' after described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawing, in which Fig. 1 is a side elevation of my improved con 0 trol device;

Fig. 2 is a bottom View thereof, looking in the direction of the arrow 2 in Fig. 1;

Fig. 3 is a plan view, looking in the direction of the arrow 3 in Fig. 1;

Figs. 4 and 5 are sectional side elevations showing the parts in different relations;

Fig. 6 is a sectional perspective view of the locking member, and

Fig. 7 is a detail sectional view showing a slight modification.

Referring to the drawing, my improved control device is mounted in a casing 10, preferably of hard rubber or some other non-conducting material. The casing is provided with an extended flange or base 11 which may be secured against a supporting structure A by screws 12.

A pair of contact members 14 and 16 are secured in an inner recess of the casing in any V convenient manner as by screws 17. The mem- 40 bers 14 and 16 are provided with ofiset contact projections 20 and are also provided with binding screws 21 by which wires W may be secured thereto. Two binding screws 21 may be provided for each member 14 or 16, so that the devices may be conveniently connected in parallel between pairs of wires W if so desired.

A U-shaped contact plate 25 (Fig. 3) is secured at its middle portion to the long arm of a lever 30, pivoted at 31 in the casing 10 and having a notched end portion 32 extending out through a slot or opening 33 in'the casing. The slot 33 is formed in the side wall of a recess 35 in the outer face of the casing 10, and a small slot 37 (Fig. 5) is formed in the opposite side wall of the recess 35.

A spring 40 is seated in a pocket 41 in the casing 19 and engages the free end of the lever 30. When the lever is free to move, the spring 40 forces the contact plate 25 against the offset contact projections 29 of the members 14 and 16, thus completing the circuit between the wires W.

A locking meinber'M is interposed between the side Wall of the recess 35 and the notched end 32 of the lever 30, as clearly shown in Fig. 4. When the locking member M is thus positioned, the spring 40 is compressed and the contact plate 25 is separated from the contact projections 20, as also shown in Fig. 4.

The locking member M may be of any suitable heatresponsive construction, but is shown in the drawing as comprising two thrust elements 44 and 45, normally secured together by a low melt ing alloy or solder S by which the parts 44 and 45 are sweated together.

The part 44 is provided with an offset end portion 44 The part 45 is preferably formed of relatively thin sheet material and is provided with an inwardly offset and down-turned end portion 48 and with downwardly and outwardly flaring wing portions 49. The portions 48 and 49 assist in holding the solder S when the parts are being secured together. A substantial portion of solder is disposed between the end of the part 44 and the down-turned end 48 of the part 45, thus more firmly securing the parts.

The inner end of the part 45 engages a shoulder 50 on the part 44, so that the member M forms arigid strut so long as the solder S remains unmelted. On a rise in temperature above a pre determined point, however, the parts 44 and 45 are released and fly apart, as indicated in Fig. 5, thus releasing the lever 30 and allowing the spring 40 to close the circuit.

The wings 49 not only serve to retain the solder as previously described, but project downward and outward when the device is in use, as indicated in Figs. 1 and 4, and materially assist in directing an upward current of warm air against the solder, thus making the member M more quickly responsive to an excessive rise in temperature.

The details of construction of the locking member are not claimed herein but form the subjectmatter of a copending application of Robert H. Russell, Serial No. 499,520, filed December 2, 1930.

.For additional protection of the contact mechanism, I preferably provide an interior cover plate secured by screws 61 and affording protection for the contact elements during shipment or whenever the devices are removed from their supporting structure. It is unnecessary to remove the inner cover when installing the device, as the contact screws 21 are accessible at the sides or the cover plate.

In Fig. '1 I have indicated a slight modification by which my control device may be adapted to closed circuit operation. For this purpose, the ends of the contact projections are bent downward so as to be engaged by the plate 25 when the parts are in normal position but to be separated when the lever 30 is releamd.

It will be evident from inspection of the drawing that my improved control device is very compact and that it occupies very slight head room, thus making it particularly well adapted for use on ship-board or in other situations where head room is limited.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:---

l. A control device for an alarm system comprising a casing of non-conducting material an inner and an outer recess and having an opening in the partition between said recesses, contact elements secured in said inner recess, a lever movably mounted in said casing and having a portion projecting through said opening, a movable contact element mounted on the inner end or said lever, a spring tending to move said lever and change the relation or said contact elements, and a heat-releasable locking member interposed between a side wall of said outer recess mu the outer end 01' said lever and normally preuqiting movement of said lever by said spring.

2.A control device iman alarm system comprising a casing 01 non-conducting material hav-- ing an inner and an outer recess and having an opening in the partition between said recesses, contact elements secured in said inner recess, a lever movably mounted in said casing and having flvol tion projecting through said opening, a movable contact element mounted on the inner end of said lever, a spring seated in a pocket in said casing and tending to move said lever and change the relation of said contact elements, and a heat-releasable locking member comprising a pair of thrust elements normally secured together by a low melting solder, said member being interposed between a side wall of said outer recess and the outer end of said lever and normally preventing movement of said lever by said spring.

3. A control device for an alarm system comprising a casing having inner and outer recesses, fixed contact elements mounted in said inner recess, a lever pivoted in said inner recess and to which a movable contact element is secured, said lever having a portion extending into said outer recess, a spring engaging said lever and tending to move said lever to change the relation oi said contacts, and a heat-releasable locking thrust member positioned in the outer recess of said casing and abutting the outer end of said lever to normally hold said lever against movement by said spring.

4. A control device for an alarm system comprising a casing having inner and outer recesses, fixed and movable contact elements mounted in said inner recess, a lever pivoted in said casing and to which said movable contact element is secured, a spring tending to move said lever to change the relation of said contacts, and a heatreleasable locking thrust member positioned in said outer recess of said casing and interposed between one end of said lever and an opposite side wall of said casing, said trust member being formed of a plurality of parts secured together by low melting solder and normally resisting endwise pressure thereon, said member thereby holdmg said lever against movement by said spring until said thrust member parts are released by the melting of the solder so that the parts thereof may move relatively to shorten said member and to relieve the endwise pressure of said spring thereon.

CLIFTON P. HOWARD.

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