US2191926A - Burglar alarm - Google Patents

Description

Feb. 27, J. E. v

BURGLAR ALARM Filed May 26, 1938 2 Sheets-Sheet 1 Jami 91725 Feb. 27, 1940. J. LEMIRE 2,191,926

BURGLAR ALARM Filed May 26, 1938 2 Sheets-Sheet 2 Z1 22 f we /0/'.'

J L/Zmqvi 5725? Patented Feb. 27, 1940 PATENT OFFICE BURGLAR ALARM Joseph Lemire, Drummondville, Quebec, Canada, assignor of fifty per cent to Norbert Boisvert, Drummondville, Quebec, Canada.

Application May 26, 1938, Serial No. 210,219

2 Claims.

The present invention pertains to a novel burglar alarm operable by switches so mounted with respect to a structure as to be altered when forcible entry is attempted. These switches are preferably mounted on doors or windows or parts adjacent thereto and are so constructed as to vibrate instantaneously with the first vibration, thereby affecting a circuit governing an alarm.

The alarm mechanism in the present instance is in the nature of a gong prepared to operate but normally locked against operation. There is also included a solenoid having a plunger adapted to fall by gravity to release the lock, preferably through the action of a tripping device.

a circuit including the above mentioned switch, so that its plunger is held inoperative insofar as the tripping mechanism is concerned. When the circuit is opened by interference with anyone of the aforementioned switches, the plunger drops on de-energization of the solenoid and thereby releases the alarm lock through the tripping mechanism.

The invention also mechanism for setting the alarm against operation during the day when the aforementioned switches are repeatedly opened and closed. This mechanism supports the plunger by positive means and prevents it from falling against the tripping mechanism. The device is operated through another solenoid which is energized when the entrance door is unlocked by means of its key. Further, this mechanism is so constructed as to break the circuit of the second solehold as soon as the plunger of the first solenoid is supported, so that a minimum of current is consumed in the second solenid.

Also included in the invention is a positive manual means for locking the tripping mechanism against operation when desired.

The invention is fullydisclosed by way of example in the following description and in the accompanying drawings, in which Figure l is a section of the alarm mechanism,

' showing also a diagram of the wiring;

Figure 2 is a detail section of the device;

Figure 3 is another detail showing adifferent adjustment of the trip mechanism; Figure 4 is a perspective view of the automatic switch for the second solenoid;

Figure 5 is a longitudinal section of the lock switch;

Figure 6 is a detail section in a plane perpen dicular to that of Figure 3;

Figure 7 is a detail section in the same plane as When set for the night, the solenoid is energized through includes an automatic,

Figure 1, showing a dilferent position of certain parts, and

Figure 8 is a section of the door lock.

Reference to these views will now be made by use of like characters that are employed to designate corresponding parts throughout.

In Figure l is shown a transformer I having one side grounded at 2 and a conductor 3 extending from the other side. This conductor passes through several vibratory switches carried 0' and is finally grounded at 15 for a purpose that n will presently be described.

A branch 66 is extended from the conductor 3 to a contact device operated by the bolt of a door as shown more clearly in Figures 5 and 8. This will now be described.

The door carrying the device is indicated at I! in Figure 8 and swings in a frame l8. The door carries a lock I9 with cylinders 20 operable from either side. The bolt 2| operable from the cylinders passes through the usual metal plate 22 30 at the edge of th frame and into a cavity 23.

A cylinder 24 is mounted in the frame and has a plunger 25 acted upon by a spring 26 so that the plunger is normally projected to the cavity 23 where it is engageable by the bolt 2|. The 35 inner end of the plunger 25 is extended-in the form of a pair of conducting plates 21, 28, the former having an insulated outer end 29, and the latter having an insulated inner end 30, the conducting portions overlapping each other at the center, for a purpose presently to be described. These plates are adapted. to enter between and engage a pair of spring contacts 3| fastened to the casing 24. The latter are connected respectively to conductors 32 and 33. It may now be seen that contact is established between members 3! only when engaged by the overlapping parts of plates 21, 28.

A suitably positioned housing 34 (Fig. 1) contains a magnetic coil 35, one end of which is connected through a conductor 36 to the conductor 32. The other end of the coil is connected at 31 to a copper plate 38 within the housing 34, and is grounded from the plate through a member 39 and a conductor 40.

The object of push button switch l3 with its movable member I3 is to ascertain if current is flowing from the transformer through the several vibratory switches. When the test is made by pushing the member l3, the buzzer l4 will sound, thereby indicating that the circuit is in order. At the same time, a circuit is maintained through coil 35, holding its plunger 4! in an elevated position. If a forcible entry is attempted, one of the vibratory switches is opened, breaking the coil circuit and causing the plunger 4| to drop and set an alarm in operation, as will now be described.

The alarm consists of a gong 42 mounted outside of the casing 34. The gong is spring wound andspring actuated by well known means not here illustrated and is associated with a hammer 43 prepared to strike the gong when the device is wound up. Action of the hammer is inhibited when the hammer is engaged by a curved lever 44 entering the casing at 45 and having a portion 46 extending upwardly within the casing. This portion carries a slotted collar 41 (Fig. 3) in which is received the bent end of a wire 48. The center of the wire is coiled to form an eye 49 to receive one end of the bent arm 50. The other extremity iii of the arm is secured to a U-shaped pivotal member 52 (Fig. 6) mounted on a pin 53 extending from the housing 34.

Through a wall of the housing 34 is passed a shaft 54 carrying at its outer end an operating arm 55 (Fig, 2) and at its inner end a curved cam member 56. When this member is turned in the upward position as in Figure 1, it raises members 48 and (being in engagement with the latter) and moves the arm 46 to the left. The parts are so constructed and weighted that they will maintain this position even when the member 56 is returned to the position shown in Figure 1. In the adjustment of the arm 46 as shown in Figure l, the hammer 13 cannot operate on the gong 42. It should be added also that Figure 1 illustrated the stay position, that is, when the device is not to be operated.

Referring now to the service or night adjustment determined by turning the member 56 to the position shown in Figure 3, it will be evident that the plunger M will drop whenever the circuit is interrupted at any of the contacts 4, 5, 6, I and 8, although the parts 4-5 and 48 remain in the position shown in Figure 1. In this position the free extremity 43 of member 48 is immediately below the plunger 4!, to be engaged thereby and to be moved to the position shown in Figure 3 when thus engaged. In this position the arm 455 releases the hammer 63 for active operation. The arm 45 is pulled by spring 5'! fixed at 58 to the casing The gong will continue to sound until its spring has been fully unwound, even though the broken contact be restored, since the return of the plunger ll does not return the arm 41 to hammer-locking position, which can be done only by manually turning the cam through its operating lever 55.

An inverted U-shaped wire 55 is mounted for vertical movement in the casing 34 as shown in Figures 1 and '7. One side of this member passes through a bracket El on the housing. The ends of a coil spring '52 engage this bracket as a collar 83 on the wire, tending to move the wire upward. The wire has a notch M normally engaging the bracket to hold the spring under tension.

As the member 51 drops under the action of the plunger 4| as above described, the edge of member 52 pushes the member 60 sufiiciently in a lateral direction to disengage the notch 64 from the bracket 6!, whereupon the member 60 moves upward. The resiliency of the member 60 at its bend suifices to permit this displacement. The bend being external of the housing, strikes the push button 65 of the switch 66 (Fig. 1). This switch is adapted to operate some other alarm and to light the lamps in the building.

The daytime adjustment is made when the look I!) is opened by turning thekey in either cylinder 20. The bolt 2| is drawn into the lock, whereupon the plunger 25 is projected to the position shown in Figure 5. In this movement, the contacts 3i momentarily pass current when the overlapping parts of the conducting portions of the plates 21, 28 pass between them in order to prevent plunger 4l' from dropping. At this moment, current flows from conductor 32 (which is always electrically connected to conductor IE) to conductor 33. It will be understood that the casing 24 is grounded. Current flows from conductor 33 to another coil 10 in casing 34 and from the coil through a conductor H to a contact 12. The latter is adapted to engage a U-shaped member i3 (Fig. 4) to which is attached a spring member 14 terminating in a lug 15 secured to the casing from the attaching screw 16 for the largest extending conductor 11 to the grounded plate 33. Thus, the completion of the circuit through coil H3 depends on engagement of members 12 and 73.

The closed circuit causes the plunger 18 of coil to rise and strike a lever 19. To the latter is secured a vertical arm 80 having its upper end set beneath the plunger 4! as shown in Figure 1. This bent end prevents the plunger from striking the member 48' and operating the alarm.

As soon as the cm-rent through conductor l6 and 33 is interrupted, the weight of plunger 41 on the bent upper end of arm 86 will depress the. arm to the extent permitted by the retraction of plunger 18 in the deenergiz ed coil 10. The weight of plunger 4| transmitted through arm 80 separates contact 13 from contact 72, since contact 13 is carried by arm 89 as shown in Figure 4. This action breaks the circuit through coil 10 after it has performed its purpose and thus effects an economy in current consumption.

In opening the circuit of coil 35 at the switches 5, ii, 1 and 8 by the normal opening and closing of the doors and windows during the day, the alarm does not operate by reason of the member 80 holding plunger 4! from falling on member 68'. Cam E6 is used only when it is desired to stop the apparatus from operating or to prevent the bell from ringing,

The plunger 25 is in two parts at collars 8| so that the mechanism with casing 24 is not disturbed if a burglar tempers with the lock.

Although a specific embodiment of the invention has been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope of the invention, as indicated by the appended claims.

What I claim is:

1. In an alarm, an audible signal, means tending to operatev said signal, a lock restraining said means, a solenoid having a plunger adapted to trip said lock, a circuit through said solenoid and normally maintaining said plunger in an ineffective position, and a control switch in saidcircuit and adapted to release said plunger for operation, another solenoid having a plunger, a device operable by saidplunger to hold the first plunger in inoperative position with respect to said lock.

2. In an alarm, an audible signal, means tending to operate said signal, a lock restraining said means, a solenoid having a plunger adapted to trip said look, a circuit through said solenoid and normally maintaining said plunger in an ineffective position, and a control switch in said circuit and adapted to release said plunger for operation, another solenoid having a plunger, adevice operable by said plunger to hold the first plunger in inoperative position with respect to said lock, and means operable by said device for opening the circuit of the second named solenoid.

JOSEPH LEM'IRE.

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