US480340A

US480340A - Burglar-alarm

Info

Publication number: US480340A
Authority: US
Publication date: 1892-08-09
Anticipated expiration: 1909-08-09

Description

(No Model.)

P. H. NEAL & J. R. DONNELLY.

BURGLAR ALARM.

No. 480,340. Patented Aug. 9, 1892.

N ITED QTATES PATENT OFFICE.

FRED H. NEAL AND JOHN R. DONNELLY, OF FAIRFIELD, MAINE.

BURGLA SPECIFICATION forming part of Letters Patent No. 480,340, dated August 9, 1892.

Application filed March '7, 1892. Serial No, 424,030. (No model.)

To all whom it may concern:

Be it known that we, FRED lil. NEAL and JOHN R.-DONNELLY, citizens of the United States, residing at Fairfield, in the county of Somerset and State of Maine, have invented certain new and useful Improvements in Burglar-Alarms; and we do hereby declare the following to be a full, clear, and exact description of theinventiomsuch as will enable others skilled in the art to which it appertains to make and use the same.

Our invention relates to a device to be ap'- plied to an electric alarm-circuit such as is connected with the doors or windows of build- 1n gs to ring an alarm when such doors or windows are opened. As those alarms have hitherto been constructed the dooror window on being opened completed the alarm-circuit which started the alarm-bell ringing, the bell continuing to ring until the door or window was closed. The continued ringing was very annoying when the alarm was accidentally set off.

The object of our invention is to limit the ringing of the alarm to a short-time while the door or window is being opened and closed and to prevent the continuous ringing above described.

The invention consists of an elliptical spring placed with its concave portion in the line of motion of the door or window and electrically connected with one pole of an alarm-circuit and an arm adjacent to said spring in connection with the other pole of said circuit, the parts being so located with reference to the door or window that as they pass by said spring it will be pushed into contact with said arm and so complete the circuit.

In the accompanying d awings we have represented a door provided with our device.

Figure lis a section on x 00 of Fig. 2. Fig. 2 is a front View of our attachment. Fig. 3 is a section on 'y y of Fig. 2.

A represents the upper end of a door, and B is the casing directly above said door.

The parts of our device are secured to a baseboard 0, which is attached to the casing directly above thetop of the door, as here shown, by means of screws 0 c. The elliptical spring E, on which the door acts, is bent up at the end to form a flange, by which it may be attached to the base-board. The main portion forms an arm which projects outward, the convex portion of the spring extending downward into the line of motion of the door, so that the latter as it opens will press the spring upward as it passes under. Directly above the spring E is an arm D, bent at the end in the same manner as the spring E and secured to the board by binding-screws f g, which pass through the arm D and the spring E. Both the arms D and the spring E are made of some good conducting material, such as brass or steel, by which an electrical current can be conducted. The bent portion of the spring E is connected electrically with one pole of an alarm-circuit and the arm D is connected with the opposite pole, the arm and the spring being insulated from each other by a layer of insulating material I. This we accomplish as follows: The binding-screw g is connected with the binding-post r in the usual way by means of a wire (1, held between the head of the screw and the metal washer Z. Between the washer and the arm D is an insulated washer '2 The inner end of the screw passes through a metal washer m, which is held between the board and the spring E. The opening through the arm D, around the screw g, is filled with insulating material, so that the screw is in electrical connection with the wire (I and with the spring E, but is insulated from the arm D. In like manner the binding-screwf is connected with the arm D and the binding-post O by means of the wire 6. The wire 0 is held between the head of the screw and the metal washerj, which is in contact with the arm D. The inner end of the screw is insulated from the spring E by a washer n of insulated material, which extends up into the opening in the spring E, through which the screw passes. The binding-post O is connected with one of the wires 1) of an alarm-circuit, and the hinding-post r is connected with the other wire a.

The operation of our device is evident from its construction. When the door swings under the elliptical spring E, the spring is for the moment pressed into contact with the arm D, whereby the alarm-circuit is completed and the bell caused to ring. The current passes through the arm a, supposing this to be the negative wire, thence over the wire (Z to the top of the screw g, down the screw g to the spring E, thence to the armD at the point where the two are held in contact by the door, thence through the screwf, wire t, binding-post O to the positive wire b, whence it passes through the alarm-circuit to the wired and c.

It is evident that the device may be secured on the casing at the side of the door instead of at the top, and it can also be placed on the casing of a window in the line of motion of the same.

We claim- The herein-described electric alarm, consisting of an elliptical spring and an arm held adjacent to each other, each having its end turned up at right angles to form a flange,