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Publication numberUS3579222 A
Publication typeGrant
Publication dateMay 18, 1971
Filing dateJan 25, 1968
Priority dateJan 25, 1968
Publication numberUS 3579222 A, US 3579222A, US-A-3579222, US3579222 A, US3579222A
InventorsFreeman Wilbern Marvin
Original AssigneeFreeman Wilbern Marvin
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Portable burglar alarm
US 3579222 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent [72] Inventor Wilbem Marvin Freeman 907 N.E. 111th St., Miami, Fla. 3316i [21 I Appl. No. 700,534 [22] Filed Jan. 2S, 1968 [45] Patented May 18, 1971 x [54] PORTABLE BURGLAR ALARM 6 Claims, 3 Drawing Figs. [52] US. Cl 340/283, ZOO/61.62, 200/6193, 340/280 [5 l Int. Cl G08b 13/08, G08b l3/00 [50] Field of Search 340/283, 280, 274. 276, 282 [56] References Cited UNITED STATES PATENTS 683,319 9/l90l McClure 340/283 723,478 3/ 1903 Mills 340/283 2,866,181 l2/l958 Gordon 340/283 2,911,637 11/1959 Wortmann 340/283 3,432,843 3/1969 Spring ABSTRACT: The burglar alarm is compact, self-contained and has no significant protrusions, but for a push rod which is pushed in flush with the case when the alarm is supported on its base or when the base is pushed against an object of value. The push rod engages a leaf spring-type switch maintaining it open; removal of force from the push rod allows the switch to extend the push rod and close actuating an alarm, for instance a buzzer and a light recessed in the top of the case. This will happen when the burglar alarm is tipped over or the object of value is moved from engagement with the push rod.

The foregoing abstract is not intended to be a comprehensive discussion of all of the principles, possible modes or applications of the invention disclosed in this document and should not be used to interpret the scope of the claims which appear at the end of this specification.

PORTABLE BURGLAR ALARM BACKGROUND OF THE INVENTION Portable burglar alarms which may be used by persons who travel to protect their valuables in hotel rooms, offices and the like are known from the prior art. However, most of such devices require the use of pulleys and strings, rod and levers, handles, extending bails or other protruding external actuating, sensing and/or carrying elements which make such devices bulky, difficult to set up quickly with a satisfactory degree of assurance that they will work, may fail to provide an alarm unless disturbed in a particularly restrictive manner and, if of the type adapted to give an alarm when tipped over, are so constructed as to be susceptible of tipping over in such a manner that the alarm given is so hidden and muffled as to be ineffective.

One prior art portable burglar alarm has an actuating switch on a side thereof and a light on the opposite side thereof. In order for the device to operate, it must be tipped over in such a sense that the switch lands downwardly, in which case the light points upwardly. However, it is easy to see that the device may easily fail to fall on the switch or fail to fall with sufficient force to turn the switch on. Such device must be heavy and bulky enough to be able to actuate the switch upon overturning, thus limiting its portability and causing it to be unsatisfactorily obtrusive for many uses.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a portable, self-contained burglar alarm having no significant protrusions, but for a push rod, which is pushed in flush with the case when the alarm is supported on its base or when the base is pushed against an object of value. The push rod engages a leaf springtype switch maintaining it open"; removal of force from the push rod allows the switch to extend the push rod and close actuating an alarm, for instance a buzzer and a light recessed in the top of the case. This will happen when the burglar alarm is tipped over or the object of value is moved from engagement with the push rod. Thus the alarm of the invention need not tip over in a particular sense, may be used against objects such as valuables or window frames as well as next to doors which open either in or out, can be easily carried in a purse or suitcase by the traveler, and requires neither time nor talent to set up quickly and properly.

The principles of the invention will be further hereinafter discussed with reference to the drawing wherein a preferred embodiment is shown. The specifics illustrated in the drawing are intended to exemplify, rather than limit, aspects of the invention as defined in the claims.

IN THE DRAWING FIG. 1 is a perspective view of the portable burglar alarm;

FIG. 2 is a bottom plan view of the portable burglar alarm; and

FIG. 3 is a fragmentary sectional view taken substantially along the line 3-3 of FIG. 2 and further illustrating the remainder of the typical electrical circuit in schematic form.

A portable burglar alarm according to the preferred embodiment of the invention includes a case 12 which is taller than thick so as to give the device, when in the orientation of FIG. 1, a relatively high center of gravity. As shown, the case 12 is generally rectangular, typically being about 4.5 inches high, 2.5 inches wide and 1.25 inches thick. The case 12 may be made of sheet metal, plastic material or the like and have one or more removable panels (for instance on the back, not shown) for assembly and for battery replacement. Also according to the preferred embodiment, the case 12 has an outwardly concave top 14, coated or otherwise provided with a shiny reflective surface 16-centrally provided with a socket which receives a heavy duty electric light bulbl8, for instance of the type used in rugged children's toys. The depth of the recess of the top 14 is such that the edges 16 are at least slightly higher than the top of the bulb 18 in order to protect the bulb.

At least two different ones of the case sides 20 are shown including sound ports 22 in order to increase audibility of the buzzer, bell, siren or other audible alarm 24 within the case. Certain audible alarms may use the case itself as a sounding board and require no sound ports. The structure of the particular audible alarm forms no part of the present invention.

A switch 26 on the case is in circuit with the visual alarm 18 and audible alarm 24, in order to allow the device to be turned off when not in use, to avoid accidental actuation, for instance, while the alarm is traveling in a suitcase or purse. Preferably, the switch 26 is of the on-off slide-type, is recessed into the case, for instance so as to be in the down position when on" or mounted to be slid horizontally between on" and off positions. Accordingly, the switch 26 is unobtrusive, does not protrude significantly and is not likely to be accidentally turned on" or off." The switch 26 also allows momentary testing of the alarm by the user to insure that the battery or batteries 28 are in working order, and that the alarm actuation assembly 30 is working properly.

As shown in FIGS. 2 and 3, the alarm actuation assembly includes a trigger" or leaf spring-type switch 32 mounted on the interior of the case I2, an opening 34 through the base of the case adjacent the switch 32 and a push rod 36 mounted in the opening. As shown, the switch 32 includes a stationary contact 38, and a spring leaf 40 bearing a movable contact 42, the spring leaf 40 normally biases the movable contact 42 into engagement with the fixed contact 38 to close the switch. The push rod 36 is upset at both ends 44, 46 so as to be longitudinally slidably retained in the opening 34. The inner end 44 of the push rod 36 engages the spring leaf 40 and the outer end 46 protrudes outwardly of the case. The restoring force of the spring leaf 40 is sufficient to extend the push rod 36 enough so that the contacts 42 and 38 engage. However, when the device 10 is set on its base, or the push rod is otherwise forced in, its end 46 enters the enlarged recess 48 surrounding the opening 34 and is flush with the exterior of the base. In this orientation, the inner end 46 of the push rod 36 forces the spring leaf up disrupting the circuit at 42, 38.

Accordingly, when a person wishes to use the portable burglar alarm 10, he may push in the push rod 36 with a finger, and slide the switch 26 to an on" condition. The person may then let up on the push rod 36 momentarily once or a couple of times to see if the audible and visual signals are given as desired. If the device is found to be in proper working order, the user then places it on its base, for instance next to a door, or on a side with its push rod forced in by engagement with an object of value, a window sash or the like. If used in the latter manner, FIG. 2 would be an elevation view thereof. When the device is tipped over by opening of the door, or when the object of value or window sash is disturbed, the push rod 36 becomes free to be pushed out by the spring leaf 40, is pushed out by the spring lcaf 40, initiating giving of an alarm signal by the light 18 and buzzer 24. No matter on which side the device It) falls, the light 18 and buzzer sound will not be hidden or muffled due to the placement thereof.

For use with doors which open outwardly, the device 10 may be inclined slightly toward the door. In view of its relatively high center of gravity,it will tip over as the door is opened.

Although provision of both audible and visual alarm signals upon actuation is preferred, elimination of either from the device would remain within the purview of the invention.

The device It) is so compact that it will be unobtrusive when used lying down on a side, for instance in a desk drawer with the push rod depressed against the edge of a stack of important papers, on a shelf with the push rod depressed against the back of a jewel case, a vase or the front of a rare book.

It should now be apparent that the portable burglar alarm as described hereinabove possesses each of the attributes set forth in the specification under the heading Summary of the Invention hereinbefore. Because the portable burglar alarm of the invention can be modified to some extent without departing from the principles of the invention as they have been outlined and explained in this specification, the present invention should be understood as encompassing all such modifications as are within the spirit and scope of the following claims.


l. A portable burglar alarm having a generally rectangular case including a flat base wall and at least one flat sidewall, the case being characterized by being substantially free of protrusions except for having a switch actuator protruding from said switch; said switch 'actuator being axially movable in said opening between a retracted condition wherein said actuator maintains said switch in an open condition and an extended condition wherein said switch is in a closed condition; resilient means on said switch engaging said switch actuator and tending to extend said :switch actuator sufficiently to close said switch, whereby said switch will remain open only so long as a an outside force on said switch actuator maintains said switch actuator in said retracted condition against the tendency of said resilient means to extend said switch actuator; said case being substantially taller than thick; and the weight of said portable burglar alarm, when resting upon said base wall, being sufficient to'overcome the tendency of said resilient means to extend said switch actuator so long as said portable burglar alarm rests :on said base, and the weight of said portable burglar alarm when resting on said flat sidewall with the switch actuator depressed against an object which may be laterally moved away from the case by a burglar, being sufficient to overcome the tendency of the said resilient means to extend said switch actuator so long as the object is not displaced; said case having means defining a top wall opposite said base wall, said top wall being upwardly concave; means defining a light reflective surface on the exterior of said top wall; means defining an electric light socket on said case exposed through said top wall centrally of said light reflective surface and connected is said circuit; and electric light bulb mounted in said socket to provide one of said at least one alarm-giving device.

2. The portable burglar alarm of claim 1 whereinsaid coni cave top wall is recessed so deeply centrally of said reflector -least one alarm-giving device includes an audible sound that the upper extent of said electric light bulb lies below the upper extent of said case peripherally of said top wall.

3. The portable burglar alarm of claim 1 wherein said switch comprises a trigger switch having a spring leaf-mounted movable contact, said spring leaf providing said resilient means; and

said switch actuator comprising a push rod having an inner end thereof engaging said spring leaf.

4; The portable burglar alarm of claim 1 wherein said at generating device. a

5. The portable burglar alarm of .claim 1 wherein said source of electric power is wholly contained within said case.

6. The portable burglar alarm of claim'l further including a slide-type on-off switch recessed in a sidewall of said case and interposed in said circuit.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US683319 *Nov 14, 1900Sep 24, 1901William G McclureBurglar-alarm.
US723478 *Apr 15, 1902Mar 24, 1903George W MillsBurglar-alarm.
US2866181 *Mar 28, 1956Dec 23, 1958Gordon Richard ABurglar alarm having both visual and audible alarm means
US2911637 *May 14, 1958Nov 3, 1959Carl Von Der Crone & CoElectric flashlights or torches
US3432843 *Jan 20, 1966Mar 11, 1969Jensen Ind IncSignal means
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3893096 *Dec 19, 1973Jul 1, 1975Cantalupi LewisHandbag alarm system
US3978321 *Aug 22, 1974Aug 31, 1976Doggett Robert EPortable hand-carried automobile counting device
US3983551 *Jul 15, 1974Sep 28, 1976Theodore S. HoffmanAlarm system for coin-operated telephone
US4520351 *Mar 8, 1982May 28, 1985Sidney AltmanPassive personal alarm device
US4797657 *May 27, 1987Jan 10, 1989Instant Security Systems, Inc.Portable self-contained intrusion detector for passenger aircraft
US5266920 *Apr 9, 1992Nov 30, 1993Eli LangnerMagnet for use on a refrigerator or the like
US5510774 *May 27, 1993Apr 23, 1996Phillips; Kurt R.Energy efficient independent alarm system
US6933846Apr 18, 2001Aug 23, 2005Visonic Ltd.Displacement sensing system
US9188487Nov 15, 2012Nov 17, 2015Tyco Fire & Security GmbhMotion detection systems and methodologies
US20040124981 *Apr 18, 2001Jul 1, 2004Mark MoldavskyDisplacement sensing system
US20050280532 *Jul 27, 2005Dec 22, 2005Mark MoldavskyDisplacement sensing system
US20070109136 *May 3, 2006May 17, 2007Kenichi HirookaPortable alarm device
U.S. Classification340/541, 200/61.62, 340/570, 200/61.93, 340/568.1
International ClassificationG08B13/08, G08B13/02
Cooperative ClassificationG08B13/08
European ClassificationG08B13/08