US187445A - Improvement in burglar-alarms - Google Patents

Description

UNITED S'IA'Ins WILLIAM D. WRIGHT, OF BALTIMORE, MARYLAND.

IMFRVEMENTIN BURGLAR-ALARMS.

Speciication forming part of Letters Patent N o. 187,445, dated February 13, 1877; application tiled December 21, 1876.

To all whom it may concern: Y

Be it known that I, WILLIAM D. WRIGHT, of Baltimore, in the county of Baltimore and State of Maryland, have invented certain new and useful Improvements in Burglar-Alarms; and I do hereby declare that the following is a full, clear, and exact description thereof', which will enable others skilled in the art to which it appertains to make and use the same, reference bein g had to the accompanyin g' drawings, which form a part of this specication, and in which Figure l is a perspective view, showing the alarm set. Fig. 2 is a longitudinal vertical section, and Figs. 3 and 4 represent modified constructions of the discharging mechanism.

l Similar letters of reference indicate corresponding parts in all thefigures.

This invention relates to that class of burglar-alarms which are arranged to be suspended from adoor or window, in such a man-A ner that the opening of the door or window causes it to fall tothe ground, thus exploding a cartridge, which has been previously adjusted in the alarm and it consists in the construct-ion and arrangement of parts hereinafter more fully shown and described.

In the drawings, A is the bodyof my im proved burglar-alarm. This consists of a block of metal or other suitable material, having, lengthwise, a recess denoted by b. Between the two arms a a, formed by this re! cess, is pivoted a hammer, B, having, if desirable, at its outer lower end, a sharp tooth or projection, c, by which the cartridge is more readily exploded. G is the trigger, which is pivoted between arms a a, behind hammer B. The lower part of thc hammer B projects, when the hammer is raised, below the arms a a, thus enablingthe trigger to be easily placed against it, in vthe position shown in Fig. l, thus keeping the hammer raised-or, in other words, setting the alarm. The hammer at its lower end has a recess, t', in which the trigger is placed, thus preventing -the accidental discharge of the alarm.

If desirable, a small spring may be-used for placing the trigger in position,-automatically, when the hammer is raised, on the princi-ple of an ordinary gun-lock; but this is not necessai-y.

The trigger is operated bya bolt, D, which A slides between arms a a, beyond which it pro- 2 ofthe drawings. It consists of" a flat piece lof metal, having at its upper and lower sides ianges e e, fitting upon arms a a, and enabling` it to slide freely. It has a longitudinal slot,V i', by which it slides upon a pin, d, which retains it in position between arms a a. The

upper side of boltD has a projection,f, which.

engages with theV upper end of the trigger, which, when the alarm is set, projects above arms a a.

The construction of bolt D may, if desirable, be modilied, as shown in Figs. 3 and 4. As it is but `necessary that the upper end of trigger C should be touched by the bolt in order to explode the alarm, the bolt may consist simply of a pin sliding in a perforation in the end of body A, which is then made solid, as shown, Fig. 3. The pin D2, in order to prevent its falling out, is slightly clinched on both ends, as shown at cl2 d2.

In Fig. 4, the bolt D3 is shownas having but one flange, namely, the upper one, the lower one being unnecessary, as the bolt slides in a recess in body A, just large enough to accommodate it. Both of these forms are cheaper than the first, and may, therefore. he used in preference to it, answering, as they do, every practical purpose.

A spring, Gr, is secured to the under side of body A, and operates the hammer B in such a manner as 4to bring it down with considerable force, when, bythe action of bolt D upon trigger C, the alarm is discharged. The body A has, directly under the head or end of hammer B, a perforation, g, in which a cartridge may be placed, which is thus exploded when the hammer, impelled by spring G, is brought down upon it. j

As before stated, the material of which my improved burglar-alarm is manufactured, is'

preferably metal; but it should be so constructed, in order to insure certainty of action, that the end having the bolt D should be Barnum QrFIGE.

much heavier than the opposite end. This is in order that, when the apparatus falls to the ground, it may fall with the bolt D down, thus forcing the bolt against the trigger, and opA eratin g the alarm.

The operation of my improved burglaralarm will be easily understood from the foregoing description, and by reference to the drawings hereto annexed. It is suspended by a string or chain, h, which passes through a perforation, h', in its light end, from a rod, H, which is inserted between the door and jamb in such a manner that, when the door is opened, it must fall to the ground. When this happens the bolt D, by being forced against the trigger, operates this and sounds the alarm, acartridge having been previously placed in the perforation g.

Instead of suspendingit in the manner just described, it may be suspended in any other suitable manner so that the opening of the door will cause it to fall; or, it may be laid sidewise upon the floor in such a manner that, when the dooris opened, it shall press against l bolt D, thus operating the alarm.

sliding between arms a d, beyond which it l projects, substantially as and for the purpose herein shown and specified.

In testimony that I claim the foregoing as my own I have hereto affixed my signature in presence of two witnesses.

WILLIAM D. WRIGHT.

Witnesses:

U. A. SNOW, WM. BAGGER.

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