Safety device for mechanically driven screw presses

摘要

In order to ensure, in a mechanically driven screw press which is provided with a braking device, that the brake is engaged independently of the speed with which the pusher rod runs back when the latter does not reach its initial position, a light barrier is fixedly arranged on the frame of the screw press and is mounted upstream of one broad face of the pusher rod, a pulse generator which extends approximately for the full length of the pusher rod is fixedly arranged on the latter, is guided between the light source and the photocell of the light barrier and has apertures, which are arranged in a row one behind the other, for the beams of light from the light source, and the light barrier is connected to a monitoring unit which processes the pulses emitted by the photocell and actuates the brake.