US2154972A - Burglar alarm - Google Patents

Description

April 18, 1939. J v. CANE GHEM BURGLAR ALARM Filed Dec. s, 1937 &WVENTOR Patented Apr. 18, 1939 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to burglar alarms andhas for an object to provide a simple cap exploding mechanism which may be easily applied to doors and windows, surreptitious opening of the door or window tripping the mechanism to explode the cap as a warning.

A further object is to provide a device of this character which will be formed of a few strong simple and durable parts, which will be inexpensive to manufacture, and which will not easily get out of order.

With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claim without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawing forming part of this specification,

Figure 1 is a front elevation of the burglar alarm device constructed in accordance with the invention applied to a window.

Figure 2 is a side elevation of the device shown in Figure 1.

Figure 3 is a perspective view of the hammer carrying and cap supporting bracket.

Figure 4 is a perspective view of the hammer.

Figure 5 is a front elevation of the device applied to a door.

Referring now to the drawing in which like characters of reference designate similar parts in the various views, designates a window sash and H the window frame. The burglar alarm device comprises a fiat substantially rectangular plate forming a bracket I2 which is adapted to be secured to the window frame near the sash by screws [3 or other connectors. The bracket is provided near the upper end with a hinge ear I4 and is provided intermediate the ends with a pair of hinge ears IS.

A boss I6 is formed on the bracket between the upper ear l4 and the lower cars 15 to receive a conventional explosive cap as for example the type known as No. copper primers. A hammer H is provided with a hinge ear !8 which is received between the hinge ears l5 and pivotally secured thereto by a pivot pin l9. The hammer is provided with a striker 20 which is adpated to impinge against and explode the cap 2| when the trigger is actuated. A leaf spring 22 is secured at one end to the bracket by a rivet 23 or other connector and the free end of the spring engages the hammer on the opposite side thereof from the striker. The spring constantly tends to urge the hammer against the cap.

An angular trigger 24 is pivotally mounted upon the upper end I 4 by a pivot pin 25. One leg of the trigger bears against the upper end of the hammer and rocks the hammer to cocked position when the opposite leg of the lever is raised by the trip 26.

The trip 26 comprises an angular rod which is removably secured in a keeper 2'! by a pin 28. The keeper is adapted to be secured to the window sash by screws 29 or other connectors. The short end of the trip extends underneath the pivotally disposed leg of the trigger 24, as shown in Figure 1, so that when the window is surreptitiously raised the trip will rock the trigger to cock the hammer and as the trigger passes off of the hammer the spring 22 will urge the hammer to strike the cap forcibly.

As shown in Figure 5 the identical parts above described are used, the only exception being that since the door 30 swings past the door frame 3| When being surreptitiously opened, the trip must be turned in the keeper to press its long leg underneath the hammer. There is no necessity for the trigger 24 when the device is used in connection with a door. Since the parts in Figure 2 are identical with the parts in Figure 1 they have been given the same reference characters.

From the above description it is thought that the construction and operation of the invention will be fully understood without further explanation.

What is claimed is:

A burglar alarm comprising a bracket plate provided at its upper end with a hinge ear and near its lower end with hinge ears, said ears extending from the face of the plate, an explosive cap receiving cylinder disposed on the face of the plate between the upper and lower ends, a hammer pivoted at its lower end to and between the hinge ears near the lower end of the plate and having an enlarged portion disposed at said cylinder forming a firing pin, a leaf spring secured at its lower end to the lower end of the bracket plate and having its upper end disposed in contact with the front side of the hammer, said spring constantly tending to urge the hammer in the direction of the cylinder, a trigger of angular formation pivoted to the upper hinge ear, one arm of the trigger being arranged in contact with the rear face of the upper end of the hammer, a block secured to a closure member, a trip bar slidably mounted in said block, the bar being L-shaped in formation, one leg of said bar being disposed in engagement with the other arm of said trigger, the engagement of the trigger with the trip bar moving the hammer outwardly against the tension of the spring and then release the hammer to permit the hammer being moved by the spring in a direction to explode the explosive cap.

JEROME V. CANEGHEM.

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