Abstract:
A vending machine is disclosed which is protected from theft or pilferage through an alarm device contained within the vending machine. The alarm device is mounted within the vending machine and sounds an alarm when the vending machine is moved or tilted more than a certain amount for a predetermined period of time. The alarm device is inexpensive, compact and easy to install requiring little modification to existing vending machines.

Description:
FIELD OF THE INVENTION 
     This invention relates to burglar alarms for vending machines. 
     BACKGROUND OF THE INVENTION 
     One of the problems facing owners of vending machines is destruction of their coin operated machines by thieves, both professional and amateur. When one tries to break into a machine, the destruction of the machine is the only way to reach the coin compartment. This wanton destruction of expensive vending machines calls for a specialized burglar alarm. 
     This invention is especially appropriate for use with newspaper vending racks. Most newspaper vending racks are formed of two parts. The top part includes a locked coin compartment which contains a coin receiving mechanism. Beneath the coin compartment is a newspaper compartment with a hinged door which is unlatched when the appropriate amount of money is deposited in the coin receiving mechanism. The vending racks are often anchored to their position by chains wrapped around sign posts or mail boxes. However, thieves often cut the chain anchoring the rack to its location. 
     No burglar alarms presently address the specific problems of vending machines. Vending machines are usually tampered with by amateurs who attempt to break into the rack and fail, but in the process damage the vending machine. More experienced thieves may have the equipment to seize an entire vending machine and remove it to a remote location before breaking into the coin compartment. 
     An alarm system designed to deal with both modes of theft must take into consideration the customers who buy goods from the rack. Slamming the door must not set off the alarm. Getting money out of the coin return should not set the alarm off and some shaking of the rack should not set off the alarm. 
     Therefore, it is an object of the present invention to provide an alarm device appropriate for use in vending machines. 
     It is another object of the invention to provide an alarm system especially designed for newspaper vending machines which is easily installed in conventional newspaper vending racks. 
     It is another object of the present invention to sound an alarm upon the occurrence of certain movements of a vending machine at the machine&#39;s location to help scare any thief and to alert the authorities to criminal activity. 
     SUMMARY OF THE INVENTION 
     The present invention provides a vending machine that is protected from theft or pilferage through an alarm device contained within the vending machine The vending machine has a housing which has a vending compartment for receiving and storing articles sold inside the vending compartment. The vending machine also has an enclosed locking coin compartment carried by the housing. The coin compartment has a coin receiving mechanism. The alarm device is contained in the coin compartment. When the vending machine is moved or tilted a predetermined amount for a predetermined period of time, an audible alarm within the alarm device sounds for so long as the box remains tilted. The alarm device is inexpensive, easy to install and difficult to disengage. More specifically, the alarm unit may comprise a tilt responsive switch having switch contacts which are activated in response to a predetermined amount of tilting from a level orientation, a delay circuit cooperating with the alarm so as to effect a sounding of the alarm a predetermined amount of time after tilting occurs. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings in which: 
     FIG. 1 shows a newspaper rack vending machine as it is normally positioned. 
     FIG. 2 shows a cutaway rear view of the coin box with top and back sides removed and the alarm unit shown in different positions inside the coin box. 
     FIG. 3 shows a cross section of the alarm unit box. 
     FIG. 4 shows a schematic drawing of the circuitry of the alarm unit. 
     Like characters refer to like elements throughout. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While the invention will be described in connection with a preferred embodiment, it will be understood that Applicant does not intend to limit the invention to that embodiment. On the contrary, Applicant intends to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. 
     Referring to FIG. 1, a vending machine, in this case a newspaper rack, is shown. The vending machine has a housing 10 formed by two parallel side walls 11, a rear wall 12 and a front wall 13. In the upper portion of the housing is provided a vending compartment 20 which receives and stores the articles vended by the machine. The vending compartment 20 has a hinged door 21 to provide access to the vended articles. The hinged door 21 has a latch 22 for maintaining the door in a normally latched condition. The housing carries an enclosed lockable coin compartment 23. The coin compartment 23 has a coin slot 24 connected to a coin receiving mechanism mounted inside. A latch mechanism 25 is also mounted within the coin compartment and is operable for unlatching the latch 22 of the hinged door 21 upon receipt of coins by the coin receiving mechanism. 
     Referring now to FIG. 2, the coin compartment 23 is shown. A coin receiving mechanism 45 is mounted interiorly of the coin compartment 23. An alarm unit 50 in the form of a compact self-contained unit, is also mounted inside the coin compartment 23. Three positions for the mounting of the alarm unit 50 are shown. Others are also possible The only requirement for the mounting of the alarm unit 50 is that it is mounted level within the coin compartment. Thus for example, if the surface upon which the vending machine is positioned is not level, the alarm device will be nonetheless mounted in a level orientation. Device 55 is a mounting strip to assist in mounting the alarm unit and leveling it. The dimensions of the alarm unit 50 are small so as to fit inside the coin compartment of a conventional newspaper box without requiring modifications. Since the alarm unit 50 is within the locked coin compartment 23 and the coin compartment is difficult to break into, it will be quite difficult to disengage the alarm. 
     In FIG. 3, a cross section of the alarm unit 50 is shown. The alarm unit 50 contains an audible alarm 60, such as a horn, which sounds when the vending machine is tilted or moved for more than a predetermined period of time. The alarm device is powered by two batteries 70 (typically, the batteries are nine volt). Since many vending machines may be in remote areas, the alarm should be quite loud. 
     As specifically illustrated in FIG. 3, the alarm unit contains a control board 80 and, the circuitry of the alarm unit is located on the board 80. An on/off switch 100 is located on the outside of the alarm unit 50 and turns power on and off. A second switch 110 will indicate whether the battery charge is low and is preferably a push button switch which lights a lamp, such as a light emitting diode (LED), to indicate that both batteries are operational. 
     Referring to FIG. 4, in operation when the switch 100 is closed the alarm device is energized by batteries 70. When the vending machine is tilted more than a predetermined amount a tilt switch S 2  closes. A variety of devices can be suitably employed as the tilt switch. In the preferred embodiment, a disk-like normally-open mercury switch is employed which is responsive to titling in any direction from a horizontal or level orientation. Preferably, the switch should be actuated (e.g. closed) in response to tilting in excess of 30 degrees, and most desirably the switch should be responsive to a tilting of 20 degrees or more. When tilt switch S 2  is closed, voltage is then supplied, to capacitor C1, here 5 volts. Capacitor C1 then begins to charge acting as a time delay for a period of time which may for example be 3 seconds. 
     As capacitor C1 charges, the voltage at switching diodes D1 and D2 increases until it reaches a certain voltage, e.g. 0.6 volts. When switching diodes D1 and D2 reaches this desired voltage, they break down and send forward biasing current to the silicon controlled rectifier SCR, which turns on the circuit, and then to transistor TR1. Transistor TR1 then activates the integrated circuit IC1. In the embodiment of FIG. 4, IC1 is a 555 timer, used to achieve accurate time delays. Pin 1 on integrated circuit 1C1 is connected to ground. Pin 2 is the trigger and receives signals from transistor TR1; pin 5 is the control voltage pin; pin 6 is the threshold pin; pin 7 is the discharge pin and pin 8 is connected to the power supply. When integrated circuit IC1 is triggered, the signal from pin 3 activates a second transistor TR2. Transistor TR2 then energizes the horn driver HD. The horn driver sounds the audible alarm and the SCR1 energizes the light emitting device LED1. 
     When the tilt switch S2 is open (i.e. vending machine is at less than the preselected angle) the current flow to capacitor C1 and transistor TR1 stops. Capacitor C1 continues to keep transistor TR1 energized while capacitor C1 discharges. Switching diodes D1 and D2 allow the capacitor C1 discharge current to flow until the voltage drops below a certain level (for example, 3 volts). At that point, switching diode D1 no longer conducts and current to transistor TR1 stops. 
     The integrated circuit IC1 operates in this time delay mode as follows. External capacitor C 2  is initially held discharged by a transistor inside integrated circuit IC1. Upon the triggering of pin 2, the flip-flop is set which both releases the short circuit across the capacitor and drives the output on pin 3 high. The voltage across capacitor C 2  then increases exponentially for a period of t=1.1R 4  C 3  at the end of which time the voltage across capacitor C 2  equals two thirds of power supply voltage The comparator then resets the flip-flop which in turn discharges the capacitor and drives the output to its low state. When current to transistor TR1 stops transistor TR1 no longer triggers pin 2 of integrated circuit IC1. A comparator inside integrated circuit IC1 resets the flip-flop, which in turn discharges the capacitor C 2 . This discharge operates to delay the changing of the output pin 3 to a low state. 
     When the output pin 3 of integrated circuit IC1 turns off, the horn driver HD is de-energized, thereby silencing the horn. Light emitting diode LED1 remains lit indicating that an alarm condition did occur. 
     In order to test the battery voltage, one pushes push button 110 which sends current to light emitting diode LED 2 which then energizes. Resistors R7 and R4 and zener diode ZD1, drops the voltage to light emitting diode LED2 so that light emitting diode LED2 will not light up if the voltage is less than a certain amount (here, 12 volts) at the source, batteries 70. This indicates low voltage and the battery should be replaced.