GB1221440A - Charging apparatus for an electrical appliance - Google Patents

Abstract

1,221,440. Battery-charging apparatus; control of motors. SPERRY RAND CORP. 31 Dec., 1968 [2 Jan., 1968; 4 Nov., 1968], No. 61841/68. Headings H2H and H2J. Apparatus for charging the battery of a portable appliance includes a control which may be selectively operated to vary the rate of charge. A motor in the appliance may be supplied either from the battery or from a rectified A.C. source. In the embodiment shown in Fig. 3, an electric shaver includes a motor MR, batteries B, a switch KS, and plug terminals ST 1 , ST 2 , ST 3 for connection to socket terminals CT 1 , CT 2 , CT 3 in a charger which comprises a mains transformer TR and a rectifier RE. To charge the batteries B fully over an extended period, the switch KS is left in the open position shown, and the transformer TR is connected to mains. Charging now takes place over conductors 30, 40 by way of resistor R<SP>1</SP> which limits the charging current to a level which allows charging to continue indefinitely. If it is required to charge the batteries quickly, e.g. for a single shave, a switch KSC on the charger is closed so that a lamp L and a resistor R 2 are now in parallel with the resistor R 1 and the overall resistance in the charging circuit is substantially reduced. The shaver may be used in isolation by closing contacts KS 2 , KS 3 so that the motor MR is energized from the batteries B, or alternatively the shaver may be operated directly from the mains using a cable connection between terminals ST 1 , ST 3 on the shaver and terminals CT 1 , CT 3 on the charger. The switch KS is moved to the position wherein contacts KS 1 and KS 3 are closed so that no connection is made to the batteries. In an alternative embodiment, Fig. 4 (not shown), the rate of charging is adjusted by changing the impedance of the circuit on the A.C. side of the rectifier.