Cash register power supply system
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to cash register power supply systems, and more particularly, to battery powered cash register power supply systems having a work system isolated from the charge system. 
     2. Description of the Prior Art 
     Previous cash register power supply systems have had the problem of having a work system not isolated from the house alternating current. Thus, if a power surge or drop occurred, for example during an electrical storm, it would be transmitted to the cash register, often adversely affecting the cash register memory. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide a cash register power supply system which will protect the cash register memory from power surges or drops in the house alternating current. 
     It is a further object of this invention to provide a cash register power supply system that is of simple and economical construction. 
     The above objects and others are obtained by providing a cash register power supply system having separate battery charging and work systems, with an electromagnetic relay and a timer providing means for switching batteries from the battery charging system to the work system and vice versa. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a schematic view of the cash register power supply system. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Shown in FIG. 1 are batteries 2 and 4, battery charger 6, electrical connections 8a-f, 10a-f, 11, 16, 21a-c, and 22a-c; electrical contacts 7a-c, 9a-c, 15a-c, and 19a-c; electrical switches 12a-c and 18a-c, relay 13 such as an electromagnetic relay; activator 14 for relay 13 such as a 24-hour alternating current timer; and cash register 20 with bottom section 17. 
     As shown in FIG. 1, battery charger 6, electrically connected to an alternating current power supply such as the house current through electrical connection 16, is electrically connected to battery 2 through electrical connections 8d-f and 21a-c, switches 12a-c, and contacts 7a-c. This forms a battery charging system. 
     Battery 4 is electrically connected to cash register 20 by electrical connections 22a-c and 10d-f, switches 18a-c, and contacts 19a-c. This forms a work system for powering the cash register 20. 
     Upon operation of activator 14, relay 13 causes switches 12a-c and 18a-c to move. Switches 12a-c break contact with contacts 7a-c and make contact with contacts 15a-c. Switches 18a-c break contact with contacts 19a-c and make contact with contacts 9a-c. Thus, battery 2 becomes part of the work system, and battery 4 becomes part of the battery charging system. When activator 14 cycles again, the switches 12a-c and 18a-c move back to their original positions, and battery 2 becomes part of the battery charging system once more, and battery 4 becomes part of the work system once more. 
     The contacts 7a-c, 9a-c, 15a-c, and 19a-c are set for late break--early make, allowing no interruptions in the power supply to the cash register 20. At no time is battery charger 6 connected to the work system, making it impossible for power surges in the alternating current supply to reach the cash register and adversely affect the cash register memory. Power surges in the alternating current supply are directed through the charger 6 into the battery being charged. In the preferred embodiment, the cash register power supply system is enclosed within bottom section 17 of the cash register 20.