Motor-driven rotary tool with internal heating temperature detecting function

Abstract

An electric motor-driven rotary tool with an elevated temperature detection function, provided by a temperature sensor, connected to a power shut off device, for shutting off power to the tool, in order to prevent injury, such as low temperature burn, from occurring to an operator of the tool, due to heating of the electric motor, encased in a housing having a holding part for the motor-driven rotary tool, causing an increase of the temperature of the housing, especially the holding part of the tool thereon, to a temperature capable of causing such burn injury to the operator of the tool. The motor-driven rotary tool, includes the electric motor in the housing therefor, the electric motor being for driving workpieces, such as a screwdriver, attached to the motor, for performing operations such as screw tightening; a torque setting and automatic stopping device for detecting a load torque generated in the rotary tool after the specified operations are completed, and for stopping the driving of the rotary tool when the load torque reaches a preset torque value; a temperature sensor installed in the housing of the electric motor for measuring an increase in the temperature of the housing, especially the holding part; and a power shutdown device for detecting a heated state of the housing by the temperature sensor, and shutting off power to the motor when the temperature of the housing increases to at least 55° C. due to heat generated by the electric motor.