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Publication numberUS2617868 A
Publication typeGrant
Publication dateNov 11, 1952
Filing dateMar 2, 1951
Priority dateMar 2, 1951
Publication numberUS 2617868 A, US 2617868A, US-A-2617868, US2617868 A, US2617868A
InventorsBurnett Menkin
Original AssigneeBurnett Menkin
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electrical burglar alarm system
US 2617868 A
Abstract  available in
Images(2)
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Claims  available in
Description  (OCR text may contain errors)

B. MENKIN 2,617,868

ELECTRICAL BURGLAR ALARM SYSTEM Nov. 11, 1952 Filed March 2, 1951 2 SHEETSSHEET l INVENTOR. BURNETT MENKIN wry/M ATTORNEY.

Nov. 11, 1952 MENKlN ELECTRICAL BURGLAR ALARM SYSTEM 2 SHEETS--SHEET 2 Filed March 2, 1951 INVENTOR.

BURNETT MENKIN ATTORNEY.

n 3 3 R f ,l 9 6 2 ms u m m n D I G 7 7 H O G 6 8 m w m 6 v J 4 A 6 0 6 Patented Nov. 11, 1952 UNITED STATES PATENT OFFICE ELECTRICAL BUBGLAR ALARM SYSTEM Burnett Menkin, New York, N. Y.

Application March 2, 1951, Serial No. 213,649

Claims. 1

This invention relates to improvements in electrical burglar alarm systems, and it relates more particularly to a signal or alarm system responsive, when in operative or set condition, to the movement of doors, windows, or the like, having protective switches associated therewith.

The principal object of the present invention is to provide an electrical burglar alarm system of the type which may be finally set by the closing of a door, whereby the last person to leave a protected building may place the system in operative condition by the mere closing of the exit door as he leaves the building.

A further object of the present invention is to provide a burglar alarm system of the character aforesaid, having improved means for rendering the various alarm circuits operative by the final closing of the exit door.

A further object of the invention is to provide a burglar alarm system of the character aforesaid having a key operated look by means of which the system may be rendered inert during the normal occupancy and use of the protected building, having improved means whereby the system may be partially set preliminarily to the final closing of the door which will complete the setting thereof.

A further object of the invention is to provide a burglar alarm system of the character aforesaid, having improved means for insuring the retention of the relay armature in the position for maintaining the alarm circuit open during the preliminary setting of the system.

A further object of the invention is to provide improved means in a burglar alarm system of the character aforesaid for indicating faults in the various circuits.

The nature and characteristic features of the invention will be more readily understood from the following description, taken in connection with the accompanying drawings forming part hereof, in which:

Figure l is a diagrammatic view of a burglar alarm system embodying the features of the present invention, the same being shown with the parts in the inert condition, such as the same would be during the periods of normal use of the protected building, when it is necessary to use the various doors and other protected openings;

Fig. 2 is a View similar to Fig. 1, but illustrating the system in its operative or set condition;

Fig. 3 is a plan view illustrating a modified form of the invention, of a more simplified char acter, but lacking certain of the desirable features shown in Figs. 1 and 2.

Fig. 4 is a view partly in perspective illustrating certain of the door operated switches used in the system; and

Fig. 5 is a view illustrating a modified form of a key operated setting lock employed in the system.

It should, of course, be understood that the description and drawings herein are illustrative merely, and that various modifications and changes may be made in the arrangements shown without departing from the spirit of the invention.

Referring now more particularly to Figs. 1 and 2 of the drawings, certain of the parts are mounted on a panel, the outline of which is indicated by dotted lines at It]. The panel is provided with a series of binding posts, A, B, C, D, E, F, and G, for convenience in wiring.

H is the battery or other source of direct current. The terminals of the battery H are respectively connected to the binding posts D and E by lines H and I2.

Mounted on the panel is a relay J, one end of the coil [3 of which is connected by line l4 to binding post A, and the other end of the coil 13.

of which is connected by line IE to the binding post B. The winding of the coil 13 of the relay J is of high resistance, of the order of about 2000 ohms. The armature IQ of the relay J is connected by line IT to the binding post E to which one of the terminals of the battery H is connected.

For the proper operation of the system it is necessary that the armature l6, when in its released or free position will not be attracted to the pole of the relay coil even when the same is energized, but for the initial setting thereof said armature must be assisted to the magnetically held position, closer to the pole of the relay magnet, in a manner to be presently described. The armature iii of the relay J is adapted, when released, to engage a contact screw [8 mounted in a bracket !9. The bracket I9 is connected by line 20 to one of the terminals of a buzzer 21. The other terminal of the buzzer 2| is connected by line 22 to the binding post G.

The winding of the coils of the buzzer 2| is such that the buzzer will not ordinarily be actuated by the normal amount of current passing through the line, but the same will be actuated under certain conditions of faults in the line, whereby an increased amount of current will be permitted to flow.

A shunt line 23 extends from line 20 to line;

22 and is provided with a normally open switch 24 included therein.

The terminals of the buzzer 2! are connected to a resistance unit 25.

Mounted on the panel adjacent the relay J is a switch lock K, the bolt 30 of which is extended when the system is inert and retracted when the system is placed in the operative or set position.

The outer end of the bolt 30 of the lock K engages a spring arm 3| which carries a cylinder 32. The cylinder 32 serves to support a plunger 33, the outer end of which is adapted under tension of a spring 34 to contact the armature E of the relay J for the purpose of positioning the armature l5 close to the pole 35 of the relay magnet l3 when the bolt 30 of the switch lock K is extended so as thereafter to hold the armature while the relay coil remains energized.

The purpose of the above described device is to insure that the armature l6 of the relay J will be held within the range of the magnetic attraction of the pole 35 of the relay J for a sufiicient period, as the bolt 30 of the switch lock is being retracted, until the main circuit is established, by the switching arrangement to be presently described, to energize the coil l3 of the relay J.

Adjacent the spring arm 3| which is controlled by the switch lock is a spring arm 35 insulated from spring arm 31 and the contact 3'! at its free end which is adapted, when the bolt 36 of the switch lock K is retracted, to engage the contact 38 carried at the end of another spring arm 39 arranged adjacent thereto.

The spring arm 36 is connected by line it to the binding post D, which is connected to one of the terminals of battery H. The other spring arm 39 is connected by line 4! to binding post F.

One of the principal novel features of the present invention is the door operated switch M which is used as the means for effecting the final setting of the alarm system to operative condition. Said door operated switch M is shown in the lower part of each of wiring diagrams of Figs. 1 and 2, and isalso illustrated in further detail in Fig. 3 of the drawings, the same comprising a plate member 50 adapted to be secured to a fixed portion of the building, such as the header of the door frame. Said plate 50 serves as a support for a cylinder 5| in which a sleeve member 52 is slidablymounted. A spring 53 within the cylinder 5| impels the sleeve member 52 to its outermost position as shown in Fig. 1 of the drawings.

In the sleeve member 52 a plunger 54 is mounted which is connected by a rod 55 to a contact disc 56 at the inner end thereof.

The contact disc 56 is adapted, when the door is open, to contact a spring arm 51 on one side, and to be seated in a notch 58 in a spring arm 59 on the other side of the supporting cylinder 5!. The spring arm 59 also has an additional notch 60 in which the contact disc 56 is seated when the door is in its closed position.

The spring arm 51 is of such length that, when the door is in the closed position, the contact disc 56 will be separated therefrom, and no current will then pass through the spring arm 57. However, there is associated with the spring arm 57 another spring arm 6| which is adapted, when the door is closed, to be engaged by a contact screw 52 carried by a bracket 63 secured to a portion of the door.

The door 0 is also provided with another bracket member or arm 64 which is adapted, as the door is closed, to first engage the sleeve member 52, and thereafter to engage the plunger 54 '4 to push the contact disc 56 to its innermost position when the door is closed.

The bracket member or arm 54 is connected to the bracket 53 by line 67 which may comprise a strip of metal foil disposed adjacent the edge of a glass panel, when such is used as a part of the door 0.

The spring arm M which is adapted to be contacted by the screw 52 is connected by line 68 to the binding post A. The spring arm 59 which has the notches engaged by the contact disc 56 is connected by line 59, which may be one of the wires of the house circuit, to the binding post G.

A line is is connected at one end to the binding post B and at its other end to binding post C. Included in the lines 59 and 15 are the normally closed detector switches i! which may be used in connection with the panels, doors and windows in the protected building, so as to break the circuit when any of the said switches are opened by reason of the opening of a door or window or other opening with which said switch is associated.

A line 12 run from the binding post F to one terminal of the alarm bell R and the return line l3 runs from the other terminal of the alarm bell R to binding post G.

A resistance unit 14 is connected across the terminals of the alarm bell R.

A shunt line i9 having a normally closed switch 8! included therein runs from the line til which connects the spring arm 39 to the binding post F. Said shunt line 79 is connected to one of the terminals of the buzzer 80, the other terminal of which is connected by line 82 to binding post G. The coils of the buzzer 85 are also of low ohm winding, and this buzzer will be actuated whenever the alarm circuit is closed. A resistance unit 83, is connected across the terminals of the buzzer 80.

A line 8Q extends from binding post C to one of the terminals of a buzzer 65 the other terminal of which is connected by line 86 to binding post E. The coils of the buzzer 35 are however of a higher ohm winding than those of the buzzers 2i and 8E].

The winding of the coils of the buzzer 85 is such that the buzzer will not ordinarily be actuated by the normal amount of current passing through the line, but will be actuated under certain conditions of faults in the line whereby an increased amount of current will be permitted to flow.

A shunt line 87 extends from one of the terminals of the buzzer 85 and has included therein a normally open switch 88. The terminals of the buzzer 85 are also connected to a resistance unit 89.

The operation of the system and patricularly the novel portions thereof may now be explained.

When the system is out of use as, for example, in the day time, during the usual and ordinary use of the protected building, the lock K is actuated, causing the bolt 38 of the lock to extend and bear against the spring arm 3! permitting the spring arm 35 to move so that the contact 31 thereof will be separated from the contact 38 which is carried by the spring arm 39.

As the spring arm 35 is connected by line 36 to binding post D, and thence by line H to one of the terminals of the battery H, it will be apparent that when the lock is thus operated, the supply of current from the battery will be cut off by the separation of the contacts 37 and 38, and the entire system will thus be rendered inert.

It-will also be apparent that when the bolt 30 of the lock K is projecting outward, as above, the spring actuated plunger 33 carried by spring arm 3| will i-mpinge. against the armature [6 of the relay J thereby breaking the circuit which comes by line I! to armature i6 and thence to contact screw I 8, thereby preventing the current from passing through buzzer 2|, or its resistance unit 25, or the switch 24 when said switch is closed.

One end of the coil l3 of the relay J is connected by line H through binding post A, and line 68 to the spring arm 5! of the door switch M, and thence through contact disc 56 to spring arm 59, to house line 69 which is connected to binding post G.

The other end of the relay coil is connected through line [5 to binding post B and through house line 18 to binding post C, and thence through the lines by which buzzer 85 is connected to binding post E. However, when the door 0 is closed, the circuit will be established from binding post A through line 68 and spring arm 61' of the door switch M, said spring arm 6! being adapted to be engaged by the contact screw 62 carried by the door, thus connecting the door panel line 67 into the circuit when the door is closed, it being noted that as the door is closed, the bracket 64 will first push the sleeve 52 inwardly until the bracket 64 encounters the plug 55 pushing the same inwardly to cause the contact disc 55 to disengage from the notch 58 of the spring arm 59, and thereafter be seated in the notch 69 of said spring arm. The circuit may thus be initially established when the door is open, and thereafter maintained when the door is closed.

When it is desired to put the system into operation the door is first opened to the position indicated in Fig. 1 of the drawings, after which the lock K is operated to cause the bolt 39 there-- of to be retracted.

The retraction of the bolt 39 results in the makingof the main circuit through the contacts 3'! and 38 so that in setting the system, the operator will first cause the bolt 39 of the lock to be retracted and then as he passes on through the door the closing thereof will cause the detector circuit to be maintained and the line on the door panel, for the protection thereof, will be cut into said circuit.

However, the relay J will be energized prior to the making of the main circuit through the contacts 31 and 38, and will thus hold the armature IS in the position shown in Fig. 1 of the drawings, whereby the circuit through the line i! coming from binding post E to line l2 will be maintained open, and the alarm bell circuit thus rendered inert until the main circuit is broken either through one of the switches II, in either of the house line 59 or m, or by the opening of said circuit through the breaking of the line 93' which protects the door panel, or the cutting of any of the wires in said circuit.

Should the door 0 be improperly opened while the system is in the operative or set condition, the contact disc 56 will be retained in the notch 68 of the spring arm 59 until after the contact screw 52 has left the spring arm SI, and in this manner the detector circuit will be opened, and the coil E3 of the relay will thereby be de-energized, thus causing the alarm bell R to ring by reason of the armature l6 contacting the screw 19 and thus establishing the alarm circuit.

In Fig. 3 of the drawings there is shown a simplified, arrangement of the circuits which,

however, will not have all the advantageous features of the arrangement shown in Figs. 1 and 2 of the drawings. As there shown, the same utilizes a panel 318 similar to the panel [0 of the other form and binding posts A B C D E and F In this arrangement the battery H is connected, similarly as in the other arrangement, to the binding posts D and E The relay J has a coil 313 connected at one end by line 3M to binding post A The other end of the coil 3l3 is connected by line 3l5 to binding post B The binding post A is connected by line 368 which constitutes one of the detector or house lines to the door setting switch M which is of the same construction as the switch M in Fig. 1 of the drawings. The other end of switch M is connected by line 369 to binding post F The lines 368 and 369 are each provided with detector switches 31! at the doors, windows and other openings of the building to be protected.

The house line 310 is connected at one end to binding post B and at its other end to binding post C and also being provided with detector switches 37!.

Binding post E is connected by line 312 to one of the terminals of the alarm bell R the other terminal of the alarm bell is connected by line 373 to binding post F In this form of the invention, binding post 0 is connected by line 384 to one of the terminals of the buzzer 385, the other terminal of which is connected by line 386 to binding post E The terminals of the buzzer 3-85 are also connected by a shunt line 381, having a switch 388 included therein.

The relay J is also provided with an armature 3 i 6 which is connected by line 3|! to binding post D The armature 3| 6 is adapted, when freed from the attraction to the pole 335 of the relay coil 3|3, to contact with the terminal 3! of the line 329. The terminal 3l8 of line 320 may, if desired, be like the contact screw [8 shown in Fig. 1 of the drawings.

The line 320 is connected to one of the terminals of a buzzer 32!, the other terminal of which is connected by line 323 to binding post F A shunt 323 extends from line 320 to line 322, having a switch 324 included therein, adapted when the switch is closed to bypass the current around the buzzer 32L The line 379 extends from binding post E to one of the terminals of a buzzer 389, and switch 38l included in said line.

The buzzer 389 has a resistance unit 389 connected in shunt across the terminals thereof, the buzzer 32I has a resistance unit 325 connected in shunt across the terminals thereof and the buzzer 38!] has a resistance unit 383 connected in shunt across the terminals thereof.

There is also provided a setting lock K the bolt 33B of which is adapted when extended to hold the armature 316 of the relay out of engagement with the contact 3l8 thereof.

The operation of the arrangement shown in Fig. 3 of the drawings is substantially similar to that shown in Fig. l with the exception of the omission of the additional feature shown in Fig. 1 of the automatic opening of the circuit by the separation of the contacts 37 and 38, carried by the spring arms 36 and 39 respectively.

In Fig. 5 of the drawings there is shown a novel form of lock switch which is so constructed and arranged that the circuit will be maintained through the relay coil during the unlocking period. As there shown, the same comprises the provision of a spring member 9| so mounted to be actuated by the inner end of the key when the'same is inserted in the lock K or K as the case may be. Said spring member 9! is connected by line 92 to line so which is connected to spring member 36, and a portion of the lock housing is connected by line as to line M which is connected to spring arm 39.

I claim:

1. An electrical burglar alarm comprising a source of electrical energy, a primary circuit in which the same in included, a detector circuit having detector switches included therein, an alarm circuit having an alarm device included therein, a relay the coil of which is included in the detector circuit, an armature controlled by said relay adapted to close the alarm circuit when the relay coil is de-energized, a switch lock having a movable. member adapted to hold the armature of the relay in circuit breaking position, a switch associated with said movable lock member adapted to open the primary circuit when the movable lock member is in position to hold the armature of the relay in its position to break the alarm circuit, means associated with the movable lock member for holding the armature in said alarm circuit breaking position until the switch in the primary circuit is closed and the relay coil thereby energized, a signal device in the alarm circuit and a signal device in the detector circuit, each of said signal devices in the alarm and detector circuits having a resistance unit in a shunt circuit whereby said signal device will be actuated in the event of faults in said alarm and detector circuits causing a variance of the current flow through said signal devices.

2. An electrical burglar alarm comprising a source of electrical energy, a primary circuit in which the same is included, a detector circuit having detector switches included therein, an alarm circuit having an alarm device included therein, a relay the coil of which is included in the detector circuit, an armature controlled by said relay adapted to close the alarm circuit when the relay coil is de-energized, a switch lock having a movable member adapted to hold'the armature of the relay in circuit breaking position, a switch associated with said movable lock member adapted to open the primary circuit when the movable lock member is in position to hold the armature of the relay in its position to break the alarm circuit, means associated with the movable lock member for holding the armature in said alarm circuit breaking position until the switch in the primary circuit is closed and the relay coil thereby energized, and a door operated switch in the detector circuit adapted, when the door is closed, after the relay coil is energized, to complete the setting of the system, and thereafter to open the detector circuit in the event the door is opened.

3. An electrical burglar alarm comprising a source of electrical energy, a primary circuit in which the same is included, a detector circuit having detector switches included therein, an alarm circuit having an alarm device included therein, a relay the coil of which is included in the detector circuit, an armature controlled by said relay adapted to close the alarm circuit when the relay coil is de-energized, a

switch lock having a movable member adapted to hold the armature of the relay in circuit breaking position, a switch associated with said movable lock member adapted to open the primary circuit when the movable lock member is in position to hold the armature of the relay in its position to break the alarm circuit, means associated with the movable lock member for holding the armature in said alarm circuit breaking position until the switch in the primary circuit is closed and the relay coil thereby energized, and a door operated switch in the detector circuit adapted when the door is closed, after the relay coil is energized, to complete the setting of the system, and thereafter to open the detector circuit in the event the door is opened, said switch also being constructed and arranged to cut in a door protective circuit when the door is closed.

4. An electrical burglar alarm comprising a source of electrical energy, a primary circuit in which the same is included, a detector circuit having detector switches included therein, an alarm circuit having an alarm device included therein, a relay the coil of which is included in the detector circuit, an armature controlled by said relay adapted to close the alarm circuit when the relay coil is de-energized, a switch lock having a movable member adapted to hold the armature of the relay in circuit breaking position, a switch associated with said movable lock member adapted to open the primary circuit when the movable lock member is in position to hold the armature of the relay in its position to break the alarm circuit, means associated. with the movable lock member for holding the armature in said alarm circuit breaking position until the switch in the primary circuit is closed and the relay coil thereby energized, a signal device in the alarm circuit and a signal device in the etector circuit, each of said signal devices in the alarm and detector circuits having a resistance unit in a shunt circuit whereby said signal device will be actuated in the event of faults in said circuits causing a variance of the current flow through said signal devices, and a door operated switch in the detector circuit adapted when the door is closed, after the relay coil is energized, to complete the setting of the system, and thereafter to open the detector circuit in the event the door is opened.

5..An electrical burglar alarm comprising a source of electrical energy, a primary circuit in which the same is included, a detector circuit having detector switches included therein, an alarm circuit having an alarm device included therein, a relay the coil of which is included in the detector circuit, an armature controlled by said relay adapted to close the alarm circuit when the relay coil is ale-energized, a switch lock having a movable member adapted to hold the armature of the relay in circuit breaking position, a switch associated with said movable lock member adapted to open the primary circuit when the movable lock member is in position to hold the armature of the relay in its position to break the alarm circuit, means associated with the movable lock member for holding the armature in said alarm circuit breaking position until the switch in the primary circuit is closed and the relay coil thereby energized, a signal device in the primary circuit adapted to be actuated when the alarm device is actuated, a signal device in the alarm circuit and a signal device in the detector circuit, each of said signal devices in the alarm and de-t tector circuits having a resistance unit in a shunt circuit whereby said signal device will be actuated in the event of faults in said alarm and detector:

circuits causing a variance of the current flow through said signal devices, and a door operated switch in the detector circuit adapted when the door is closed, after the relay coil is energized, to complete the setting of the system, and thereafter to open the detector circuit in the event that the door is opened.

6. An electrical burglar alarm comprising a source of electrical energy, a primary circuit in which the same is included, a detector circuit having detector switches included therein, an alarm circuit having an alarm device included therein, a relay the coil of which is included in the detector circuit, an armature controlled by said relay adapted to close the alarm circuit when the relay coil is de-energized, a switch lock having a movable member adapted to hold the armature of the relay in circuit breaking position, a switch associated with said movable lock member adapted to open the primary circuit when the movable lock member is in position to hold the armature of the relay in its position to break the alarm circuit, means associated with the movable lock member for holding the armature in said alarm circuit breaking position until the switch in the primary circuit is closed and the relay coil thereby energized, a signal device in the primary circuit adapted to be actuated when the alarm device is actuated, a signal device in the alarm circuit and a signal device in the detector circuit, each of said signal devices in the alarm and detector circuits having a resistance unit in a shunt circuit whereby said signal device will be actuated in the event of faults in said alarm and detector circuits causing a variance of the current flow through said signal devices, and a door operated switch in the detector circuit adapted when the door is closed, after the relay coil is energized, to complete the setting of the system, and thereafter to open the detector circuit in the event the door is opened, said switch also being constructed and arranged to cut in a door protective circuit when the door is closed.

'7. An electrical burglar alarm comprising a source of electrical energy, a primary circuit in which the same is included, a detector circuit having detector switches included therein, an alarm circuit having an alarm device included therein, a relay the coil of which is included in the detector circuit, an armature controlled by said relay adapted to close the alarm circuit when the relay coil is de-energized, a switch lock having a movable member adapted to hold the armature of the relay in circuit breaking position, a

switch associated with said movable lock member adapted to open the primary circuit when the movable lock member is in position to hold the armature of the relay in its position to break the alarm circuit, means associated with the movable lock member for holding the armature in said alarm circuit breaking position for energizing the relay coil prior toand until the switch in the primary circuit is closed, said means comprising a shunt circuit around the switch in the primary circuit and means included in said shunt circuit to close the same upon insertion of a key in the switch lock.

8. An electrical burglar alarm comprising a source of electrical energy, a primary circuit in which the same is included, a detector circuit having detector switches included therein, an alarm circuit having an alarm device included therein, a relay the coil of which is included in the detector circuit, an armature controlled by said relay adapted to close the alarm circuit when the relay coil is de-energized, a switch lock having a movable member adapted to hold the armature of the relay in circuit breaking position, a switch associated with said movable lock member adapted to open the primary circuit when the movable lock member is in position to hold the armature of the relay in its position to break the alarm circuit, means associated with the movable lock member for holding the armature in said alarm circuit breaking position for energizing the relay coil prior to and until the switch in the primary circuit is closed, said means comprising a key controlled shunt circuit around the switch in the primary circuit.

9. In an electrical burglar alarm system including a detector circuit having detector switches therein, a door operated switch in said detector circuit adapted to complete the setting of the system, said switch comprising a pair of spring arms, a contact member adapted to contact both of said arms and thereby maintain the circuit when the door is open, said contact member being movable to a position to break the contact with one of said arms when the door is closed, an auxiliary contact arm electrically connected to said last mentioned arm adapted to be engaged when the door is closed by a contact member carried by the door, another member carried by the door adapted to actuate the movable contact member when the door is closed and to establish an electrical connection therewith, an electrical connection between the members carried by the door, and means for restraining the movement of the movable contact member when the door is opened until the contact member carried by the door is separated from the auxiliary contact arm.

10. In an electrical burglar alarm system including a detector circuit having detector switches therein, a door operated switch in said detector circuit adapted to complete the setting of the system, said switch comprising a pair of spring arms, a contact member adapted to contact both of said arms and thereby maintain the circuit when the door is open, said contact member being movable to a position to break the contact with one of said arms when the door is closed, an auxiliary contact arm electrically connected to said last mentioned arm adapted to be engaged when the door is closed by a contact member carried by the door, another member carried by the door adapted to actuate the movable contact member when the door is closed and to establish an electrical connection therewith, an electrical connection between the members carried by the door including a protective line positioned marginally on a panel of the door, and means for restraining the movement of the movable cont-act member when the door is opened until the contact member carried by the door is separated from the auxiliary contact arm.

BURNETT MENKIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,365,693 Hess Jan. 18, 1921 1,758,523 Kertz May 13, 1930 2,243,804 Howton May 2'7, 1941

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1365693 *Apr 8, 1918Jan 18, 1921Hess Simon BThermostatic burglar-alarm system
US1758523 *Feb 8, 1929May 13, 1930Nat Wiring & Protective Co IncBurglar-alarm system
US2243804 *Jun 7, 1938May 27, 1941Howton Radio Alarm CompanyAlarm system
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2721239 *Jun 2, 1954Oct 18, 1955Willy KufferBurglar alarm
US2838748 *Jun 4, 1954Jun 10, 1958Susan HorvathSecurity locks
US2922150 *Apr 19, 1957Jan 19, 1960Jezl AntonDoor alarm
US3042910 *Jun 16, 1960Jul 3, 1962Shull Frank TAlarm equipped cabinet for fire extinguisher
US3160720 *Jul 14, 1961Dec 8, 1964Electro Sound CorpAlarm system and switch means
US3815117 *Sep 25, 1972Jun 4, 1974Paymaster CorpAlarm apparatus for office equipment
US3866164 *May 22, 1973Feb 11, 1975Hinge Manufacturing CompanySecurity system and lock therefor
US5311168 *Sep 10, 1992May 10, 1994Pease Industries, Inc.Lock set with self-contained door alarm and annunciator system
Classifications
U.S. Classification340/545.1, 200/61.78, 340/545.4, 340/545.2, 200/61.82, 200/61.66, 200/61.58R
International ClassificationG08B13/08, G08B13/02
Cooperative ClassificationG08B13/08
European ClassificationG08B13/08