Matsushita Electric Works, Ltd.

Hiromi Kakumoto

Kaoru Furukawa

Makoto Miyata

Yoji Iguchi

Shinji Ihara

Kouichi Iwanaga

An electric shaver with a trimmer is disclosed in which a single flexible seal is used to protect the motor and electric parts from water and other material entering through the perforated comb or the trimmer.

Electric shaver

A battery charger includes a transistor inverter. The transistor inverter includes an oscillation transformer and a switching transistor for controlling a current flowing through a primary coil of the oscillation transformer. This current charges the battery when the transistor is on. While the switching transistor is in an off state, charging current is supplied to the battery from a secondary coil of the oscillation transformer. The period of time where the switching transistor is in an on state is controlled depending on the amplitude of a supply voltage. Accordingly, the average value of a charging current to the rechargeable battery is automatically kept substantially constant despite variations in the amplitude of the alternating current voltage supply.

Battery charging circuit for maintaining a substantially constant

A diode is disposed in the vicinity of a rechargeable battery. A current is applied to the diode from a current generating circuit. The current generating circuit comprises a thermistor which is responsive to the ambient temperature, so that a current associated with the ambient temperature is applied from the current generating circuit to the diode. The diode gives rise to a forward voltage drop, which is changeable as a function of the battery temperature. Accordingly, the forward voltage drop across the diode is changeable as a function of the ambient temperature and the battery temperature. The forward voltage drop across the diode is amplified to be used as a reference voltage. On the other hand, the rechargeable battery is supplied with a charging current from a power supply through a thyristor. The gate electrode of the thyristor is connected to receive the reference voltage and the cathode of the thyristor is connected to the battery. Accordingly, the thyristor is turned off if and when the difference between the reference voltage and the battery voltage becomes smaller than the switching voltage of the thyristor.

Charging apparatus

Battery charging device having a function of indicating in sounds at least one of charging and discharging states of a storage battery, specifically adapted to be incorporated in battery operated electric implements. During charge operation, a charging circuit oscillatorily generates from a rectified direct current of commercial AC source current a high frequency charging voltage, of which oscillation becomes intermittent with varying intervals after a predetermined battery charge level is reached, whereby a charge complete detecting circuit causes a sound generating device to be operated to sound discriminatively initial and final charge complete indications responsive to the varying intervals. During discharge operation, a charge remind detecting circuit provides an output to the sound generating means only after a predetermined discharge level is reached, to cause the means device to be operated to sound a charge remind indication.

Growing community of inventors

Hikone, Japan

Hiromi Kakumoto