Device for displacement measurement, for example measuring of the return travel during mining operations in coal mining

摘要

A displacement measuring device, for example for measuring the return travel of a conveyor extending in a face by means of pressureless or hydraulic thrust piston mechanisms essentially consists of a cylinder housing, a piston which can slide therein and has a piston rod, and a measuring device which records the piston movement. In order to avoid sources of error, the thrust piston mechanism (1) is provided with a digital measuring device, the inner surface of the cylinder housing being formed over the entire length alternately from metal and plastic rings (7, 8), and there being provided arranged offset in the piston (3) two intrinsically safe proximity switches (M1,M2). <IMAGE>