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Publication numberUS2851680 A
Publication typeGrant
Publication dateSep 9, 1958
Filing dateSep 17, 1956
Priority dateSep 17, 1956
Publication numberUS 2851680 A, US 2851680A, US-A-2851680, US2851680 A, US2851680A
InventorsLa Cavera Frank J
Original AssigneeLa Cavera Frank J
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Burglar alarm
US 2851680 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

p 9, 1958 I F. J. LA CAVERA 2,851,680

- BURGLAR ALARM Filed Sept. 17, 1956 3 Sheets-Sheet 1 7 IN V EN TOR.

Filed Sept. 17, 1956 Sept 9, 1958 i Q F. J. .LA CAVERA I 2,851,680

BURGLAR ALARM I v I Q 35heets-Sheet 2' INVENTOR.


Sept. 9, 195a F. J. LA CAVERA I BURGLAR ALARM 3 Sheets-Sheet 3 Filed Sept. 17, 1956 INVENTOR.

BURGLAR ALARM Frank J. La Cavera, Cleveland, Ohio Application September 17, 1956,.Serial No. 610,053.

' Claims. (Cl. 340-283) This invention relates to a burglar alarm device, and particularly to a compact portable signal. operating mechanism which can readily be; installed at the site to be protected.

More particularly, the alarm is one which, when it is tripped, causes a succession of different alarm signals in delayed timed relation to. each. other.

For the purpose of illustration the alarm is shown. as one which fires successively a number of cartridges, closes a switch. for the turning. on. of the lights in an establishment to be guarded, and. causes operation of an audible signal, such as a siren or a buzzer, all in a preselected sequence. 7

The: deviceis. one in which-the-internal mechanism is operated by a suitable self-contained power unit, such as a battery driven motor, and in which means are. provided for indicating externally of-the device whether or not it has been. properly-set for operation, and. whetheror not ithas been released and has: operated.

Further, it is one; in which means. for indicating whether the cartridgesrhave been-fired or'not also provide a means for shielding the discharge ends of the nozzle of the gun elements in which the-cartridges are detonated so as to protect the operator from accidental discharge.

Anotherfeaturev of the device resides: in the locking mechanism of the door or cover of the cabinet in which the device is contained. being-so arranged that the unlatching. and opening of the cover renders thedevice inoperative thereby permitting the internal mechanism. to.

be handled without danger.

Another feature resides: in the testing means-by which the operation of each signal can be. tested easily and the readinessof the device for operation can be. checked.

Various objects and. advantages will become apparent from the. following description, wherein reference is made to the drawings, inwhich:

Fig. l is a perspective view of. a form. of the device embodying a preferred. form.- of. the invention;

Fig. 2 is, a front elevation. of. the device with the door or cover open so as to expose the working elements;

Figs. 3 and 4 are: vertical sectional views taken on the lines. 33 and 4-4, respectively, of Fig. 2, parts thereof being shownin elevation for clearness. in illustration; and

Fig, 5 is awiring diagram of the device illustrated in Figs. 1 through 4.

Referring to the. drawing, the device comprises a cabinet, indicated generally at 1, and having a top wall 2, end walls 3, a rear wall 4, and a bottom' wall 5. The

front of the cabinet is closed. by a suitable hinged cover 6.which, when swung to open position, renders the entire interior readily accessible.

nitcdstates Patent "ice ism comprises a self-winding reel 8 on which is. wound a suitable cord: 9. An attaching ball or element 10', adapted to be received detachably in a suitable; snap fastener, is attached to the free or outer end of: the cord 9, so as to hold the cord in extended position against the pull of. the spring of the reel. 8. The: tripping mechanism is one which can be set'readily bypulling. upwardly ona rod 11 which temporarily is held in' a raised position by a spring. seated detent 1-2soas to. permit free unreeling of the cord 9 against the force of the winding spring of the reel.

The tripping, mechanism is arranged so that after the I desired amount of line or cord 9 is reeled out and the element 10 is. secured. in: itsdetachablefastener, the: rod 11 canbe released by pulling the detent 12 to theleft. When released, the rod 11 moves downwardly and'sets the tripping mechanism, This mechanism. is such that if the cord 9 is pulled or released: so as to cause rotation of the reel in either direction a very few degrees, the tripping, mechanism will trip. and allow the rod'11 to descend to its fully lowered position.

As shown in the above. identified application, electric switch 13, shown in Fig. 5,. is arranged to be heldiclosed when the rod 11 is.- in its raisedposition and to be opened when= the, rod 11 is moved to: its; loweredposition;

Mountedwithin the; casing. 1 are cartridge firing devices or guns 14, two beingshownforpurposes'offillustration and. each having. a: barrel 15. The, guns are mounted on a suitable bracket 16 which, in turn, is secured to: a supporting; plate-17; connected to theback wall: 4 in fixed position relative'thereto;

Extending, forwardly from the front 'faceof plate 1 7 arezupright' supporting plates 18, 1-9 and"20,,respectively.

On the bracket 16 aresuitable internally threaded bosses 22 each of which hasaninternally threaded. cerrtralibore for engaging complementary. threads-23 on. the lower, end of its; associated barrel: 15? so that the barrel can be screwed thereinto and supported therebya in up.- right position for discharging upwardly.v

The barrels 15 are-adapted to receive cartridges, as indicated at 24, each cartridge beingin'serted in: the lower end of its associatedbarrelwhile the: barrel isunscrewed from its boss 22..

Each bosshasa reduced diameter counterbore and an annular shoulder 25 between. its. central bore. and counterbore. When the barrel is. installed. with a cartridge therein, the annular shoulder 25 engages. the: bottom of the cartridge and holds it in position for firing- Connecting with the lower end of each: ceunterbore' of each boss: 22' is a further reduced diameter bore in: which is reciprocably mounted a firing. pin: 26.. Beneath the bracket 16 are detonating hammers 27, respective to: the guns 14. Since the hammers 27 arealike in form and function one only will he described in detail.

Each hammer 27 is mounted on a'suitable springv sup port 28 by which, when the spring is. unstressed, it is supported in: a position. slightly below its associated firing pin 26. In the form illustrated, the spring support; 28 is connected to the bracket 16 by: a suitable bolt and nut 29. Each spring isarrangedrsothat, when. stressed down.- wardly, so as to movetitshammer 27 farther from the normal position of rest, and then released it will swing its hammer 27 upwardly beyond the normal posit-ion of rest'and deliver a sharp blow on the pin 26 sufiicient to cause the'pin to detonate the-cartridge 24.

In order to stress the springs so as to move the hammers downwardly from their position of rest and thenrelease the springs suddenly, cams 30 are provided, one for each hammer. The earns 30. are mounted in fixed position on a common shaft 31 for rotationtherewith; Since the guns are to fire in succession, the cams 30 are spaced apart angularly with respect to each other about the axis of the shaft 31.

The shaft 31 is rotatably driven by a gear 32 which, in turn, is driven by a gear 33. The gear 33 is rotatable with a gear 36 which is driven by gear 37. The gear 37 is driven through a shaft 38 by a battery operated electric motor 39. Due to this reduction gear train, the cams 30 may be operated by low output, battery powered motor.

In addition to the alarm signals provided by the guns described, there is provided within the cabinet 1 an audible signal, such as a buzzer 40, which is electrically operated and arranged to emit loud and readily discernible sound when the buzzer is energized.

In addition, a plug-in receptacle 42 is mounted within the cabinet with its outlet accessible from the outside through one of the end walls 3 so that an external two- Wire circuit can be plugged in to the receptacle when the door or cover of the device is closed. A suitable twowire cord or cable 44, adapted at its outer end to be plugged into an ordinary base plug source of 115 volt power enters the cabinet through the end wall 3. One wire in the cord 44 is connected directly to one terminal of the receptacle 42 and the other wire in the cord 44 is connected to the other terminal of the receptacle 42 through a pair of spaced contacts 45d and 45a of a face-plate switch 45 (Figs. 2 and the contacts 45d and 452 being arranged to be bridged by a contact segment 45c upon rotation of the face plate. The switch 45 together with a face-plate switch 46 are mounted on the shaft 31 for rotation therewith.

A suitable enclosed fuse is provided between the plugin end of the cord 44 and the receptacle 42.

The motor 39, in turn, is arranged for energization by batteries 47 which are detachably clamped in the cabinet by means of a yoke, indicated generally at 48, the lower ends of the arms of which are pivotally mounted as at 49 so that the yoke can be swung upwardly into embracing relation to the batteries.

Mounted in the top wall 2 of the cabinet are firing indicators 50 which are aligned with the gun barrels 15, respectively.

Each indicator 50 comprises a member which is movably mounted in the cabinet and which has a portion extending outside of the cabinet where it is easily visible. Each movable member, shown for illustrative purposes, comprises a rod 51 slidably mounted in the top wall for movement axially. At its upper end, outside of the easing, each rod is provided with a bolt which limits the retracted or lowermost position of the rod. At its lower end, within the casing, each rod is provided with a combined shield and lift 53. The rods fit in their mountings with a drag fit so that when in raised or extended position, they remain therein against the force of gravity but can be pressed down to retracted position by hand.

Each of the shields 53 is aligned with its associated gun barrel and is of suflicient area so that the force of the gases discharged by its gun, upon firing of a blank shell thereby, can blow the associated indicator to extended position, as shown by dotted lines Fig. 2, against the frictional drag.

The door 6 of the cabinet is provided with a latch having a latch element 54. A single pole double throw microswitch 55 is mounted in the casing for operation by the latch element 54 so that, as the latch element is moved into latching position, it moves the switch 55 to one of two closed positions. The switch is self-restoring and moves to a different closed position when released.

On the door or cover is a main key operated cut-out switch 56 and a co-rotatable test switch 57, by which a test circuit can be connected to certain of the signal circuits for testing them. The key receiving element of the switch 56 is indicated at 58.

The various switches and circuits will be apparent from the wiring diagram of Fig. 5, now to be described.

In the wiring diagram, the face-plate switches 45 and 46 are shown in starting position in which the device is ready for tripping by an intruder, and the door or cover 6 is assumed to be closed and latched so that a blade a of the switch 55 is in engagement with a contact 55b and disengaged from a contact 550.

The switch 45 may be a dual-face switch with opposite faces having identical contacts and thus operating as a single switch whereas theswitch 46 is a dual-face switch with faces 46a and 46b each of which has differently arranged contacts and segments.

Also in Fig. 5, the rod 11 is assumed to be lowered so that the switch 13 is open and the switch 64 is closed. The switch 56 is in its on position with a blade 56a disengaged from a contact 56e and engaged with a contact 56 The switch 57 is open with a blade 57a disengaged from a contact 57b.

The blade 55a of the switch 55 is connected by a line 60 to the positive side of the batteries 47. The contact 55b is connected by a line 61 to the blade 56a of the switch 56. The contact 550 is connected by a line 62 to a contact 460 of the switch 46. The contact 56a is connected by a line 63 to one terminal of the switch 64. The switch 64 is open until the reel 8 is set for operation, but it closes and remains closed when the rod 11 is lowered. A line 65 serves as a common connection to the negative terminal of the batteries 47.

Testing Testing is done by inserting a key into the tumbler 58 and turning so that the blade 57a engages the contact 57b and the blade 56a leaves the contact 56 and engages the contact 56e. This completes a circuit from the positive side of the batteries 47 through the line 60, the blade 55w, the contact 55b, the line 61, the blade 56a, the contact 56s, and a solenoid 66 interposed in a line 67 leading to the negative terminal of the batteries 47 through the line 65. The resultant energization of the solenoid 66 releases the pin 11 which lowers and closes the switch 64.

Closure of the switch 64 completes a circuit from the batteries 47 through the line 60, the blade 55a, the contact 55b, the line 61, the blade 56a, the contact 56s, the line 63, the switch 64, the buzzer 40 and the line 65 to the batteries 47. If the detent had not been released, the rod 11 would not be in its lower position and the switch 64 would not be closed so that the circuit to the buzzer 40 would not have been completed. Only with the reel 8 in properly set position is the sound of the buzzer 40 heard when the test switch 56 is in test position. Similarly, the buzzer 40 would not have operated had the door been opened causing the switch 55 to be in its other (broken line) closed position. A pilot light 82 connected in parallel with the buzzer 40 bylines 81 and 83 becomes lit when the buzzer 40 sounds.

At the same time that the blade 56a is turned to engage the contact 566, the blade 57a of the switch 57 turns to engage the contact 57b. This completes a circuit through the cable or cord 44 for the outside lamps which are plugged into the receptacle 42. This circuit includes conductors or lines 70, 71, 72, and 73 and is traced from one side of a source at 74 through the lines 73 and 72, the contact 57b, the blade 57a, the line 70, and the outside lamps (not shown) plugged into the receptacle 42 interposed in the conductor 71.

If the outside lightsbecome illuminated and the buzzer 40 sounds with the key in test position, the operator knows that the cabinet is locked, the plunger 11 is released, and all circuits are in proper operating condition.

Operation After testing, the tumbler 58 is returned to operate position breaking the circuit to the outside lamps at the 9 switch 57 and causing the blade 56a to engage the contact 57 The device is now ready for operation.

Upon closure of the reel switch by 13 tripping of the mechanism 7, the motor 39 is energized and drives the face-plates of the switches 45 and 46 clockwise. The motor circuit is through the line 60, the door switch 55, the'key switch 56, a line 75, the reel switch 13, a line 78, the contact 46h, the segment 46g, the contact 46 the line 77, the motor winding 39, and lines 76 and 65 to the negative side of the batteries 47.

Rotation of the motor 39 turns the shaft 31 and thereby operates the earns 30 so as to fire the guns 14 in succession, this timing and succession being determined by rotated position of the earns 30 on the shaft 31.

Within a very short time interval after the motor 39 starts, the segment 46g engages the contact 46g. This completes an auxiliary circuit for the motor 39 which is independent of the switch 13 and which extends from the positive side of the batteries 47 through the line 60, the switches 55 and 56, the line 75, a line 85, the contact 46d, the segment 46g, the contact 46], and the line 77 to the motor 39.

A short time later, a contact segment 46m has been driven clockwise until it bridges contacts 462 and 46k. The buzzer 40 now sounds and the pilot lamp 82 becomes lit. The circuit for the buzzer 40 is through the portion of the auxiliary motor circuit previously traced to the contact 46d and from there to the contact 46e, the segment 46m, the contact 46k, a line 80, and the buzzer 40 to the line 65. The lamp 82 is lit because it is connected in parallel with the buzzer by lines 81 and 83.

At about the same time that the buzzer 40 starts to sound, the outside lights become energized and lit by completion of the circuit from the contact 45d through the segment 45c to the contact 45e.

The motor 39 continues to operate so long as the segment 46g engages the contact 461. When the segment 46g leaves the contact 46f the motor 39 stops. The circuits previously traced to the buzzer 40, lamp 82, and the outside lamps remain completed so that a continuing alarm is maintained.

The device is shut off and the alarm terminated by opening the door 6 which causes the blade 55a of the switch 55 to leave the contact 55b. The blade now engages the contact 550 completing a circuit through the line 62, the contact 46c, the segment 461', and the contact 46 to the conductor 77. The motor 39 restarts and runs until the segment 461' leaves the segment 45 and then stops. The face-plates 45 and 46 are now in the starting position shown and the cams 30 are positioned for a subsequent sequential operation. The buzzer 40, lamp 82, and outside lamps are all deenergized at this time.

If desired, a normally open switch 84 may be arranged to be closed by opening of a window. Any number of similar normally open switches may be connected in parallel with the single switch 84 illustrated. The switch 84 is in parallel with the switch 13 and its closure initiates the same operation as closure of the switch 13.

The importance of the auxiliary circuit for the motor 39 through the contact 46d is apparent when the switch 84 is used. For example, assume that the switch 84 is closed by unauthorized opening of a door. The intruder might hear the motor 39 start and thereupon close the door. If it were not for the auxiliary motor circuit this would stop the device from further operation and its purpose would be defeated. The time interval between starting of the motor 39 and completion of the auxiliary switch is made so short that it is practically impossible to reclose a door or window equipped with a switch such as 84 to prevent continued operation of the alarm device.

Heretofore mention has not-been made of a switch 86 interposed in the line 75. The switch 86 is shown in its closed position and must be closed if the alarm de- 6 vice is to function. Ordinarily the switch 86 would be located outside of a building and would be closed after the building is'locked. This enables the person setting the device to leave the building by a door equipped with the switch 84 without causing unintentional operation of the device. Since the switch 86 is to be mounted in a remote location, it is not shown as a part of the device of Fig. 1 through 4. A jumper (not shown) can be connected across the switch 86 for testing purposes.

Summarising the setting and operation therefore, the following steps are taken in order:

(a) Lift rod 11 of the reel to free the reel. opens switches 13 and 64.

(1)) Close and latch door. tween blade 55a and contact 55b.

(c) Draw out cord 9 of reel and connect its end to a retainer by element 10.

(d) Release rod 11 to set tripping mechanism. This closes switch 64 but not switch 13.

(2) Turn key to engage blade 56a and contact 56s and to close switch 57, thus testing. Because of switch 64, the reel must be set before audible signal 40 can operate. Test shows whether door of case is closed and locked. Whether reel is set for tripping, whether outside lighting circuit is operating, and whether the alarm 40 and pilot lamp 82 are operating.

(f) Release the key switch, thus connecting the blade 56a with the contact 56].

(g) Burglar trips the reel mechanism by tensioning or releasing cord 9 or closing switch 84. The motor 39 is energized.

(h) Motor operates part-way through cycle, causing guns to fire, alarm 40 to operate, and lights to come on, then stops, the lights and alarm 40 remaining on.

(i) Unlatch door. This connects pole 55a with contact 550. The alarm 40 thereby is turned off. The lights remain on. Motor operates to move to starting position.

(i) The switch 45 is operated to turn off the outside lights. Motor is automatically stopped in starting position.

Having thus described my invention, I claim:

1. In a burglar alarm including a settable tripping mechanism, a cartridge firing mechanism, and means operatively connecting the mechanisms for causing explosion of a cartridge upon tripping of the tripping mechanism, a visual indicator, means normally supporting the indicator in a non-signalling position and for movement to a signalling position, and operative when the indicator is moved to signalling position to retain the indicator in said signalling position until restored to the non-signalling position by an operator, said indicator having a portion positioned to be moved by the explosive force of a cartridge detonated by said firing mechanism and operative when so moved to move the indicator to signalling position.

2. Structure according to claim 1 characterized in that said detonating mechanism includes a gun barrel, said indicator comprises a rod, means to support the rod for axial movement and frictionally hold in the position in which it is moved axially, a shield is carried by, and movable with, the rod and aligned with the discharge end of the barrel so as to be moved by an explosive discharge therefrom.

3. A portable burglar alarm comprising a portable cabinet, a plurality of alarm devices therein, a settable tripping mechanism therein and having a member extendind outwardly therefrom for operating the mechanism from a location remote from the cabinet, an electric motor, a battery connected thereto, the tripping mechanism, when tripped, closing a circuit to the battery and motor, said battery and motor being enclosed in said cabinet, control means in the cabinet and drivable by the motor for initiating operation of the alarm devices, a normally open electric switch arranged to be closed by the control means when the control means is driven by the This This makes contact bemotor, a plug-in receptacle carried by the cabinet and accessible from the outside of the cabinet for plugging in an external circuit, a plug-in cord connected to the receptacle for connecting an external source of power to the receptacle, and said switch being connected in a circuit with the cord in series with the receptacle.

4. A burglar alarm comprising a plurality of electrical- 1y operated alarm devices, control means therefor including motor driven electric switches connected to the motor for driving thereby, control circuits connecting the devices and switches for energizing the devices when the switches are driven into predetermined positions, respectively, by by-pass circuits for the devices respectively, a common manually movable test control element movable selectively to ditferent selected positions, switch means operable by the test control element to energize the devices, selectively, by the by-pass circuits and concurrently to render them inoperative by the said control means.

5. A burglar alarm comprising a plurality of alarm devices, a motor, a settable tripping mechanism adapted, when tripped, to initiate the operation of the motor, control means connected to the motor and driven thereby when the motor operates and operative, when driven by the motor to preselected positions, to initiate operation of the alarm devices successively, and power means for driving the motor, a portable cabinet containing said tripping mechanism, alarm devices, control means and power means, a door on the cabinet, latch means operable from the outside of the cabinet for latching the door, means operated by the latch means upon movement of the latch means to latching position to set up a circuit which is to be operable by tripping of the tripping mechanism, a normally open switch means and a normally closed switch means in series in said circuit, a device for setting the tripping mechanism and operative to open the normally closed switch means and then to close the normally open switch means when moved to set the tripping mechanism and said tripping mechanism being connected operatively to the normally closed switch means to cause closure of the normally closed switch means when the tripping mechanism is tripped.

References Cited in the file of this patent UNITED STATES PATENTS 542,664 Thomson July 16, 1895 914,173 Norpoth Mar. 2, 1909 1,326,803 Tapley Dec. 30, 1919 1,965,946 Pincus et al. July 10, 1934 2,170,521 Rodth Aug. 22, 1939 2,187,194 Chapman Jan. 16, 1940 FOREIGN PATENTS 10,591 Great Britain May 15, 1908

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US542664 *Oct 2, 1894Jul 16, 1895The electric Gas Lighting CompanyElectric annunciator
US914173 *Sep 28, 1908Mar 2, 1909Theodor NorpothElectric alarm.
US1326803 *May 12, 1919Dec 30, 1919 Auto-theft indicator
US1965946 *Jul 7, 1931Jul 10, 1934Gen Burglar Alarm Co IncAlarm device
US2170521 *Feb 6, 1936Aug 22, 1939Rodth Joseph RAlarm lock
US2187194 *Mar 13, 1937Jan 16, 1940Avada StormBurglar alarm
GB190810591A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2970560 *Oct 1, 1958Feb 7, 1961Perrin Jean L FAnti-burglar electro sound alarm system
US4319228 *May 28, 1980Mar 9, 1982Daniels Edward HPortable intrusion alarm
U.S. Classification340/514, 340/385.1, 340/691.5, 89/27.14, 340/815.69, 340/668, 116/6, 340/565, 116/23
International ClassificationG08B15/00
Cooperative ClassificationG08B15/00
European ClassificationG08B15/00