US2704814A - Circuit makers and breakers for signal or alarm circuits - Google Patents

Description

J. 5. WHITE 2,704,814 CIRCUIT MAKERS AND BREAKERS FOR SIGNAL OR ALARMCIRCUITS March 22, 1955 Filed July 23, 1951 I But" in;

Enventor Jesse 5 ruse WhiLE M fl fi attorney United States Patent CIRCUIT MAKERS AND BREAKERS FOR SIGNAL 0R ALARM CIRCUITS Jesse Spruce White, Miami Springs, Fla. Application July 23, 1951, Serial No. 238,113

2 Claims. (Cl. 307-132) This invention relates to circuit makers and breakers particularly of a type for signal or alarm circuits.

A primary object of my invention is to provide combined switch mechanism which is responsive to complete a circuit responsive to conditions prevailing at the location of the mechanism and to interrupt the circuit intermittently at said location whereby the curent is controlled so as to flow in intermittent impulses when the prevailing conditions are such as to effect the closing of the circuit for transmitting such impulses.

Another object of my invention is to provide a control switch which is adapted for operation by thermal conditions or under the influence of physical conditions rendering the mechanism operative to transmit such impulses due to excessive temperatures for operating fire alarm or signal systems or whereby the mechanism may be used in connection with burglar alarm systems.

Another object of my invention is to provide such a combined signal switch mechanism which is inexpensive to construct and simple and eflicient in its operation.

Further objects and details of my invention will appear in the following description supplemented by the accompanying drawings forming a part of this specification.

Referring to the drawings:

Fig. 1 is a side elevation view of a combined signal switch mechanism in accordance with my invention.

Fig. 2 is a vertical sectional view thereof.

Fig. 3 is a fragmentary plan view thereof.

Fig. 4 is a vertical sectional view thereof taken substantially on the line 4-4 of Fig. 3.

Referring to the drawings, in general the switch mechanism in accordance with my invention includes a rectangular casing of insulating material provided with transverse bores 11 for receiving bolts to hold front and back cover plates (not shown) thereon when desired. This casing houses a control switch A with an upwardly extending operating rod 12 and an intermittent circuit interrupter B.

As diagrammatically shown in Fig. 2 my switch mechanism is particularly adapted for use in conjunction with a movable object C such as an object which may rest thereon when the mechanism is mounted in a floor, or in conjunction with a door, window or the like so that the operating rod 12 is depressed to maintain the circuit controlled by the mechanism open.

In Figures 3 and 4 my switch mechanism is shown in use with a fusible split ring D which maintains the control switch A open wherein it is applicable in a fire alarm system. Thus it will be seen that the mechanism is adaptable for various uses though primarily intended for burglar or fire alarm systems.

In a preferred construction the casing 10 is formed with mounting bases 13 and 13 for the respective control switch A and circuit interrupter B. Casing 10 has a bore hole 14 in its mounting base 13 through which operating rod 12 extends and a well 15 concentric therewith provides a housing for a compression spring 16 which engages a disk-like collar 17 to urge the rod to its upper circuit closing position as shown in Fig. 1. Collar 17 is housed in a concentric opening 18 surrounding rod 12 in the upper portion of casing 10 when the rod is depressed to circuit opening position as shown in Figs. 2, 3 and 4 and this opening is provided with a groove 19 adjacent to the upper surface of casing 10 into which the fusible split ring D may be inserted for retaining the rod in its open circuit position when the mechanism Patented Mar, 22, 1955 isk used in conjunction with a fire alarm system or the The lower end of rod 12 carries a flexible metallic disk 20, a set screw 21 and lock washer 22 holding the same in place so that it will be carried to reciprocate between the circuit opening and closing positions of rod 12. This disk 20 provides the movable contact element of the control switch A which is reciprocable to engage and disengage from a pair of fixed contacts 23 comprising set screws which also function as binding posts for conductor leads. When the operating rod 12 is in circuit closed position spring 16 urges it upward so that flexible disk 20 is brought into a tight engagement with the end surfaces of contacts 23, the flexibility thereof insuring good current conducting engagements with both of them even though conductor leads of slightly different diameters or thicknesses may be employed.

While the circuit interrupter B may be of any desired type my preferred construction comprises a bimetallic thermal element 32 which is normally bowed downwardly and secured in place on mounting bases 13' of casing 10 by set screws 24 which also provide binding posts for lead conductors. A contact post 25 is positioned in a midpoint between the ends of bimetallic strip 32 and has a silver plate 26 on its upper end which electrically engages the bimetallic thermal element under normal temperature conditions. Contact post 25 has a collar 27 illustrated as hexagonal in shape at its base which engages the lower wall of casing 10. A threaded extension 28 extends from collar 27 through a similarly threaded opening through the casing 10 for receiving it and a nut 29 thereon secures the contact post 28 in place. It is also provided with a reduced threaded extension 30 carrying a nut 31 which provides a lead conductor binding It will be seen that set screws 23 and 24 and nut 31 provide binding posts by means of which the control switch A and circuit interrupter B may be connected as desired in a signal or alarm circuit of any well known type and they are adapted for operation in either direct or alternating circuits. While no signal system or alarm circuit is illustrated conductor leads 33 and 34 for the control of such systems by my control mechanism are illustrated as desirably connected with one of the binding post set screws 23 and under the binding post nut 31 to contact post 25. The control switch A and circuit interrupter B are connected in series in such circuit by a conductor 35 extending from the other set screw binding post 23 to one of the set screw binding posts 24.

In such a circuit it is clear that when control switch A is closed under changed conditions-removal of object C, or fusing of ring D or the like-current passing through the control switch A and interrupter B will heat interrupter strip 32 and cause it to bend to disengage its contact with post 25, thus intermittently interrupting the current flow in the signal or alarm circuit as long as the circuit is under the influence thereof.

It will be noted that the collar 17 normally resting on the bottom of opening 18 closes the well 15 in which the spring 16 is disposed, thus isolating the spring with respect to the outside of the casing 10 to prevent the accumulation of foreign matter in the well. This is of importance when the mechanism is installed in the floor where dust and dirt settles by gravity and in the act of sweeping foreign matter may be moved over the casing 10, some of it falling into the opening 18. The normal engagement of the collar 17 upon the bottom of opening 18 also limits the extent of movement of the rod 12 inwardly of the casing 10, so that the spring 16 cannot be compressed to the extent where the convolutions of the spring touch one another and which might otherwise cause the spring to become permanently set in a fully compressed condition, especially if subjected to consid erable heat. The collar 17 also serves to somewhat insulate the spring from gas of high temperature, such as would result from a fire, in the zone of the signal switch mechanism. The arrangement is such that a fused ring D may be replaced by a new one without gaining access to the main compartment of the casing 10.

I claim:

1. A signal switch mechanism including a rectangular casing of insulating material, mounting bases extending inwardly from walls thereof, said casing having an opening therethrough between the ends of one of said mountings and a concentric well in the outer portion thereof terminating at the outer wall with a further enlarged concentric recess having a groove in its circular wall adjacent to the surface of the casing wall, a fusible split ring having its peripheral edges engaged in said groove, a reciprocable rod extending through said opening having a collar thereon adapted to be seated in said enlarged concentric recess and to be retained in its seated position by the fusible split ring engaging the groove in the recess above the collar, a compression spring in said concentric well for moving the rod outward upon the fusing or removal of the split ring from the groove, a flexible metallic diaphragm carried by the inner end of said movable rod, and set screws in said mounting base adjacent to the ends thereof at opposite sides of said reciprocable rod providing lead terminal binding posts and the heads thereof serving as contact members adapted to be engaged by the flexible disk on said reciprocable rod when the rod is forced outwardly by said compression spring.

2. A signal switch mechanism including a rectangular casing of insulating material, mounting bases extending inwardly from walls thereof, said casing having an opening therethrough between the ends of one of said mountings and a concentric well in the outer portion thereof terminating at the outer wall with a further enlarged concentric recess having a groove in its circular wall adjacent to the surface of the casing wall, a fusible split ring having its peripheral edges engaged in said groove, a

reciprocable rod extending through said opening having a collar thereon adapted to be seated in said enlarged concentric recess and to be retained in its seated position by the fusible split ring engaging the groove in the recess above the collar, a compression spring in said concentric well for moving the rod outward upon the fusing or removal of the split ring from the groove, a flexible metallic diaphragm carried by the inner end of said movable rod, set screws in said mounting base adjacent to the ends thereof at opposite sides of said reciprocable rod providing lead terminal binding posts and the heads thereof serving as contact members adapted to be engaged by the flexible disk on said reciprocable rod when the rod is forced outwardly by said compression spring, a bimetallic strip secured at its ends to a remaining pair of said mounting bases projecting from a wall of the casing by means of set screws which also function as conductor terminal binding posts, a contact post threadedly caried by the wall of the casing between said mounting bases and extending inwardly and outwardly of the casing, a silver surface or plate on the inner end of said post against which said bimetallic strip lies in electrical contact engagement when said control switch circuit closing diaphragm is out of engagement with said contact members thereof, and a lead terminal binding post on the outer end of said contact post.

References Cited in the file of this patent UNITED STATES PATENTS 527,375 Rowand Oct. 9, 1894 606,076 Ovenden June 21, 1898 1,095,382 Clorius et a1. May 5, 1914 1,159,602 Scheuer Nov. 9, 1915 1,182,283 Lutz May 9, 1916 1,494,335 Boston May 20, 1924 1,785,366 Shoenberg Dec. 16, 1930 2,029,097 Garner Jan. 28, 1936 2,276,428 Soreng Mar. 17, 1942 2,439,502 Tate Apr. 13, 1948

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