US2374139A

US2374139A - Burglar alarm

Info

Publication number: US2374139A
Application number: US401030A
Authority: US
Inventors: Oliver L Schriner
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-07-03
Filing date: 1941-07-03
Publication date: 1945-04-17
Anticipated expiration: 1962-04-17

Description

April l' 1945., o. L. scHRlNER 2,374,139

BURGLAR ALARM I Filed July s, 1941 WITNESSES: INVENTOR. v

Patented Apr. 17, 1945 .-muriel). sourires PATENT orificev BURGLAR ALARM p oliver L. sommer, Attica', Y.; Appiicatn .my 3, 1941, serial No. 1p1-,oso

(c1. zoo-52) '-.Thisinvention relates to a burglar alarm and has forl an'object to providev essentially a circuit closer formed' of nested metal pipes insulated from .each other and adapted to closea circuit toi electrically voper-ated alarm devices when an attempt is made to saw through the pipes,- the pipes beingadapted to form a closure for openings to be protected 'as well as to forman inclosure for localities 'to be protected.

A lfurther object is to provideaburglar alarm of this character which will be operated by direct current in the event of failure of the normal alternating current due to tampering orsome other causes. Y

A further` object is to provide apparatus 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 a part of this specification:

Figure 1 is a fragmentary front elevation with parts in section, showing a burglar alarm circuit closer constructed in accordance with the invention and' showing the electrical connections thereof with alarm devices.

Figure 2 is a detail longitudinal sectional view points. The outer pipe has its ends extended through and welded to a hollow metal frame inu cluding upper and lower bars I3 and I4, and end bars I5, one of which is shown. The bars of the frame constitute a ground as well as a mounting to dispose the bars I0 to form a closure for an opening to be protected, or to form an inclosure for a, locality to be protected.

- upper vend of the outer pipe H.

The inner pipes I2 are supported in spaced relation to the outer pipes by lower, upper', and in some cases intermediate insulators i6, II and I8 respectively. The lower insulator is supported Within the lower end ofthe outer pipe by a metal cap I9 which is screwed on to said end of the pipe and then welded't'o the bottom metal bar I4. The upper endof this insulator is reduced as shown at 2U and extends into the lower end of the inner pipe I2.

The upper insulator Il surrounds the upper end 0f the inner pipe I 2 and extends into the It is secured in place by a flange 2I which overlaps the upper end of the outer pipe I I. The intermediate insulator I8, when used, is of annular form and surrounds the inner pipe as well as contacts with the inner. surface of the outer pipe. The intermediate insulator is held in place by screws 22 which are threadedly engaged in the inner pipe above .and below the insulator and have their heads engaging with the top and the bottom of the insulator, see Figure 2. The pipes I0 and II form terminals of a circuit closer when a surreptitious attempt is made to saw through the pipes, the hack saw Aforming rbridging contact between the terminals during the sawing operation.

The bars III are wired for both direct and alternating current and for this purpose a circuit wire 23 is trained through the frame formed by the hollow bars I3 and is bared of insulation at spaced points and welded, or otherwise electrically connected, to the projecting upper ends of the inner pipes I2, as shown in Figure 3. The wire is connected to a signal wire 24 which is connected to one terminal of an alarm device such as an electric bell 25. The `other terminal of the alarm device is connected by a signal wire 26 and armature 35 to one terminal of the secondary coil 2'I of a step down transformer, the primary coil 28 of which is connected to supply wires 29 from an alternating source of current.

When the outer pipe Iis sawed through and the hack saw touches the inner pipe the alarm circuit will be closed, and may be tra-ced from the secondary coil 2l of the transformer through the alarm device 25, to the signal wire 24, thence to the conductor wire 23 through the inner pipe I2 to the outer pipe II and to the hollow bar I4 which is grounded as shown at 3l.

Should the alternating source of supply fail, it is desirable that storage battery current be used to operate the burglar alarm when a surreptitious attempt is made to cut through the bars I0.

For this purpose a storage ibattery 32 is connected by conductor wire 33 to one terminal 34 of a switch of which this spring retracted armature 35 forms a part. The other terminal 34a of the switch is connected by a Wire 36 to one terminal of the electric bell 25a. It will be pointed out that when the alternating source of supply is in operation the step down transformer functions as a relay which coacts with the armature 35 to hold the direct current line, which is traced, open at the

terminals

34 and 34a but when the alternating source of supply fails the transformer becomes dead and the controlling spring of `the armature 35 closes the direct current line at the terminals 34 and 34a. l

To complete the directed alarm circuit a signal wire 31 is connected to the other terminal of the alarm device 25a and is connected to a circuit wire 38 which is trained through the frame formed by the hollow bars I4, I and I3 and isconnected at intervals to conductor wires 39 which pass through the bottom insulators I8 andare trained axially upward in the inner pipes I2.

kThe upper end of each wire 39 is secured in place by an insulator 40 which snugly ts within the inner pipe I2. When the alternating source of current fails the direct current circuit is closed by the circuit closure formed by the inner pipe and the axial wire 38 after both pipes have been sawed through. The direct current circuit may b e traced from the batteries 32 to the wire 33, armature 35, wire 36, alarm'device 25a, wire 31, wire 38, axial wire 39, and grounded outer pipe I I.

From the above description it is thought that 'having upper end lower sides in which the bars are mounted, the ends of the outer pipes extending through and welded to said sides of the frame to electrically connect the outer pipes thereto, the lower ends of the inner pipes terminating short of the corresponding ends of the outer pipes and lthe upper ends of the inner pipes extending above the corresponding ends of the outer pipes, lower and upper insulators spacing the inner pipes from the outer pipes, metal caps supporting the lower insulators within the outer pipes, the caps being screw threaded on the lower ends of the outer pipes and welded to the lower side of the frame, the upper ends of the lower. insulators being, reduced and extending into the lower ends of the inner pipes,v the upper insulators extending-into the upper ends of the outer pipes in surrounding relation to the upper ends of the inner pipes, an insulated conductor housedk within the frame and electrically connected to the extended upper ends of the inner pipes, a second insulated conductor housed within the frame, and conductors located axially within the inner pipes and extending through said lower insulators, said conductors having their lower ends connected electrically to said second conductor and having their upper ends insulated from the inner pipes.

OLIVER L. SCHRINER.