Electric motor control based on conductive contact of machine component with operator for injury prevention

摘要

A unit for controlling the operation of the electric motor is provided together with a control device, electrically connected to the body of the operator, to act on the control unit via a relay means in such a manner as to halt and reverse the rotation of the electric motor following conductive contact between the operator's body and the metal component. For receiving and supporting the feet of the operator, two conductive plates insulated from the ground are provided in such a position that the operator rests his feet via conductive shoes on them when working with the machine. The plates are connected to the control device, and the metal component is electrically connected to earth. The support plates are electrodes for the passage of low voltage electric current from one plate to the other via the body of the operator. The control device stops the motor following conductive contact between the operator's hands and the metal component.