US3192517A - Burglar alarm - Google Patents

Description

United States Patent O 3,192,517 .BURGLAR ALARM Isadore Werlin, Medford, Mass., assignoto Bay State Security Corp., Arlington, Mass. Filed May 11, 1962, Ser. No. 193,976 1 claim. (Cl. 340-276) This invention relates to burglar alarms and more particularly comprises a new and improved alarm which may be Secured to any closure without special fittings or mounting panels and detect either movement of the closure or relative movement of the alarm and closure.

The value of alarms to detect unauthorized access into closed places is too obvious to require amplification. Clearly the better an alarm is able to detect unauthorized access, the more desirable is the alarm. `While burglar alarms are available in all shapes, sizes and prices to protect stores, dwellings, safes, automobiles, etc., ol am unaware of any alarms that are available for the protection of substantially all closed spaces, which donot require special fittings etc., to be supported in place. The lack of such alarms is particularly acute'in railroad `yards and sidings where loaded freight cars are regularly stored. The protection of freight cars presents a peculiar problem as all of the alarms of which I am aware necessitate the breaking of the seals applied to the doors of loaded cars by the carrier to be mounted on the doors. Security companies and freight owners are most reluctant to break the seals to open the doors so as to attach the alarms because the breaking of the seals shifts responsibility for the freight car contents. Thus, freight cars are a typical example of the type of closed chamber for which my alarm is particularly suited.

One important object of this invention is to provide a burglar alarm which' may be attached to virtually any surface without the necessity of defacing or otherwise altering the surface to which the alarm is to be Secured.

Another important object of this invention is to provide an alarm which is sensitive to both movement of the surface upon which it is mounted and relative movement between itself and the surface.

Yet another important object of this invention is to provide an alarm having a signaling system which may not be disabled without actuating an alarm signal.

To accom'plish these and other objects this invention includes among its many features a housing containing a magnetic coupling device adapted to retain the housing on any magnetic surface. A number of switching devices are mounted in the housing including vihration and orentation sensing switches which are adapted to energize an alarm. Additional switches are contained in the housing which are loaded merely by the contact of the housing with the surface on which it is mounted, and these switches activate an alarm circuit in the housing when the housing is removed from the surface.

3,19Z,5l7 Patented June 29, 1965 12 mounted on wall 14 by rivets, screws or other fasteners as suggested at 16. The case 10 may be of virtually any shape but should include one wall 18 that may lie flat against the surface 20 on which it is mounted. face may of course be a door, window or any other member which when closed restricts access to the region to be protected by the alarm. i

The wall 18 is provided with a pair of openings 22 through which the legs 24 of horseshoe magnet 26 extend. The pole faces 28 of the legs 24 lie in the plane of the outer surface 30 of the wall 18 so that they make contact with the surface 20 upon which the case is to be mounted with the wall 18 lying flat on that surface. While the magnet 26 shown is of the permanent type and of a horseshoe configuration, it is to be understood that the magnet may take other shapes and may be an clectromagnet energized through wires in cable 32 to be described below in connection with the various sensing devices disposed These and other objects and features of my invention along with its incident advantages will be better understood and appreciated from the following detailed description of two embodiments thei-cof, selected for purposes of illustration and shown in the accompanying drawing, in which:

FIG. 1 is a side view partly in section of an alarm constructed in accordance with this invention; v FlG. 2 is a cross sectional View, partly diagrammatic and similar to -FIG, 1 showing another embodiment of this invention; and

FIG. 3 is a schematic diagram of an alarm circuit which includes the switching devices contained in the alarm shown in FIG. l.

The embodiment of this invention shown in FIG. 1 includes a case 10 having a convenient carrying handle in the case 10. The magnet 26 possesses sutiicient strength to retain the case 10 With its normal contents in any orientation on a surface 20 without additional support.

A pair of additional openings 34 are provided in the Wall 18 of the case and are sized to receive at least the blades of microswitches 36 secured to the wall 18 or other walls of the case by any convenient means. While the microswitches 36 may be of any variety, preferably eachhas a blade 38 disposed in the plane of the face 30 of the wall 18 and biased by a spring to extend out of the wall 18 and beyond the plane of surface 30. That is, under the influence of the biasing means contained as part of the switches which are normally open, each blade 38 does not engage its fixed contact 42, and the circuits containing the switches are consequently opened. However, when the case 10 is mounted on a wall such as surface 20 and held in place by the magnet 26 the blades 38 of the switches 36 are depressed against the influence of the springs and make contact withthe fixed contacts 42. Thus, it will be appreciated that by the selection of appropriate circuits the switches-36 may be employed to detect any relative movementbetween the case 10 and the surface upon which the case is mounted. Some additional sensitivity may be acquired by orienting the switches 36 perpendicular to one another so that the blade of one switch is normal to the blade of the other. As illustrated in FIG. 1, the blade 38 of the upper switch 36 is oriented generally vertically while the blade of the other switch is disposed horizontally in the case. As a result, if the case 10 is pivoted even slightly about a horizontal axis such as defined by the lower oorner 44 of the case, this moveopens in response to a sharp blow or impact upon the case 10. In FIG. 1 the switch 50 is mounted on the upper wall 56 of the case but it will be readiiy apprev ciated that the switch requires no special orientation.

The other switch 60 shown in FIG. 1 is motion detector having -a fixed ring contact 62 and a pendulumlike stem 64 carrying a cone-shaped contact 66. The cone-shaped contact is adjustable on the stem 64 by means of the set screw 68 so that it may be raised or lowered on the stem to vary the sensitivity of the switch 60. When the case 10 is oriented properly on the supporting surface 20 the stem 64 pivotally supported on the arm 70 will position the cone-sh-aped contact 66 within the ring contact 62 without the two contacts engaging one an- That sur- 66 to engage the ring contact 62 and consequently close the circuit which includes the motion detector 60.

'As suggested above and shown in the drawing a cable 32 enters the case through the lower wall 72 an'd carries a number of conductors which serve to connect the various switches within the case 10 to a control panel remote from the alarm. In FIG. 3 a typical installation is shown. The case 10 isrepresented by the broken' V lines 10' in FIG. 3 while the control panel 80' is represen-ted by a second box also described by broken lines. It will be noted in FIG. 3 that the microswitches 36 and the vibratorswitch 50 are connected in series and complete a circuit across terminal-s 1.1 and L2 through .conductors 82, 84, 86 and hattery 88. Conductor 82 also includes another normally closed switch 90 forming part of a relay that is .described below. The two e microswitches 36 and the vibrator switch 50 may be connected within the ease 10 through a simple circuit omit- `ted for purposes ofclarity in FIG. 1.

The normallyopen motion detector switch 60 is shown in FIG. 3 to be connected in series by means of leads 92 and 94 with the battery 88 and a relay coil 96 which controls the position of the normally closed relay switch 90 in conductor 82. Thus, when the normally opened motion detector switch closes, it energizes coil 96 through the battery and conductors 92 and 94 to open switch 90 in the circuit of the other switches 36 and 50.

-From the foregoing description it will be recognized that when the alarm case 10 is mounted on the surface of a closure such as a door or window, removal of the case 10 from the closure will open switches 36 to de-energize the circuit across terminals Ll and L2. A sharp vibra v tion of a preadjusted amplitude will also cause that circuit to open by opening at least momentarily vibrator switch 50. Any motion of the case 10 either on or from the support 20 will cause the `normally open -motion detector switch 60 to close which will energize relay 96 to open relay switch 90 and subsequently de-energize the circuit across terminals Ll and L2. Moreover, any at- --tempt to tamper with the circuits by cutting the eable 32 which carries conductors 82, 84, 92 and 94 will also open the circuit between terminals Ll .and L2. However,

when the alarm is to be intentionally removed from its supporting surface for any reason or the circuits are to be serviced, the normally open switch 104 in the control panel 80' may be closed by a special keyor other impliment to close the circuit across terminals Ll and L2 and the goods contained within the chamber protected by' the alarm. It should also be recognized that several burglar alarms similar to that shown in FIG. 1 may be connected to and operate through the single control panel 80. For example, if two freight cars were tobe proand motion detector switch 60 the case 10" contains a battery 100 and transmitter 102. The battery and transmitter may be connected to the microswitches, vibrator and motion detector by a circuit identical to that shown in FIG. 3 with the battery 100 connected as battery 88 in that circuit and the transmitter 102 connected across terminals Ll and L2. In this manner the transmitter 102 may transmit a signal to a local or remote authority continuou-sly. to indicate, that the alarm is in a safe condition, and ouly'when the switches 36, 50 and 60 are moved from their normal position will the transmitter cease to transmit a safe signal. When the transmitter is contained 'within the alarm case, certain advantages exist in arrangingthe circuits so that the transmit-ter only renders a signal when some disturbance is detected and under safe or normal conditions is inactive.

When 'the -transmitter, operates in this manner, it is impossible for anyone seeking unauthorized access to dupli- 'cate the transmitter signal by some other device and then remove the alarm, thereby gaining undetected access to theregion protected by the alarm. The transmitter 102 may also be tone modulated for the purpose of unit tional types of sensing switches may be employed such as heat detecting switches typically made of bimetallic elements, and light detecting switches' including photoelec tric cells, which respond to the presence of an abnormal heat or light .condition. It will also be appreciated from the foregoing description that the alarm case may be mounted on any surface made of magnetic material and even in the absence of such a surface a metal plate may be attached to the inside or opposite side of the wall,

panel, door, window, etc., upon which the alarm is to be mounted to cooperate with the magnet 26 to provide a base for securing the case 10 in position. Furthermore,

.the alarm case need not be provided with openings for the pole faces of the magnet.` Rather, when the magnet is of sufiicient strength a non-magnetic cover may form the side of the housing through which the magnet acts and not interfere with operation of the magnet as a coupling. Moreover, the handle 12 may where convenient provide a fixture through which a chain orother fastener may be i passed to physically lock the alarm in place.

tected by alarms, the microswitches and vibrator switches i V `of the several alarms could be connected in series so that the opening of any one of them would de-energize 'the circuit across the terminals Ll and L2. The motiondetector switches on the other hand cont-ained in the several alarm cases would be connected in parallel across lines 92 and 94 so that the closing of any one of said Having described my invention in detail those skilled in the art will appreciate that numerous -modifications may be made of it without departing from' its spirit. Therefore, I do not intend to limit the breadth of this invention to the specific embodiments illustrated and described.

Rather, it is my intention that the scope of this invention What is claimed is:

An alarming comprising V a housing having a flat wall adapted to lie in face to face relationshp against a flat surface of a wall defining a closure for a region to be protected,

na magnetic coupling device mounted in the housing and having a pair of poleaces in the plane of the outer surface of the flat wall for securing the housing against the wall of the closure,

means defining a pair of openings through the flat wall of the housing,

a pair of microswitches mounted within the housing and each switch biased to open condition, each of the switches having pivotally movable blades within one opening and with the blades oriented substantially 5 5 perpendicular to one another, said blades being biased for rendering an alarm in response to a change in to move outwardly of the housing and adapted to be the condition of said crcuit.

held within the plane of the fiat wall of the housing t References Cited by the Examie' and close the microswitches when said flat wall lies in face to face contact with the fiat surface, 5 ED STATES PATE E a normally closed vibrator switch confined to the hous- 13205742 8/33 Chapman et al ing and opened in response to sudden motion of the x h i g, a normally open switch mounted within the housing 10 ustfsson and closed by tiltin of the housing 1 cep er i 2,943,308 6/ 60 Westphal 340--276 a normally close crcut ncludng the lIlICI'OSWltChCS 2,97L186 2 61 Rpepi 34o 276 and the vbrator switch and broken by the wg 3951 934 8 62 Lesher 340 224 said d h ed d 3,o56,951 i 10/62 Tooni 340-276 x an a ition norma y cose switc connect in sai 15 circut, FOREIGN PATENTS means including a relay energized by the closing of the 483332 5/52 Canada' normally open switch in the housing for opening 744311 2/56 Great f i additional c Great B'tam.

and signaling means electrically connected to the circuit 20 NEIL C. READ, Pr'mary Exmrer.

Images