Hand tool operated by an electric motor

Abstract

Abstract A hand tool operated by an electric motor is proposed in which the risk of injury to the operator and damage to the tool by the tool continuing to run is eliminated by means of a fast braking device. The tool comprises a circuit for the motor, which includes a power supply from the alternating-current mains with a current which never changes its sign (34 to 37) and a short-circuit braking circuit (31 to 33, 38 to 52). It also contains a manual brake which operates as an electromechanical brake solenoid (10, 15, 16). The combined supply short-circuit braking circuit eliminates a failure of the short-circuit brake during switch-off at the instant of the zero transmission of the magnetic flux. Both braking devices are preferably controlled by a common switch (29). <IMAGE>

Inventors

• 👤 Hans Gerber
• 👤 Ulrich Heiniger
• 👤 Fritz Ing.-grad. Schädlich

Bibliographic Details