Continuous distance measurement in mine workings - uses cable with drum and interchangeable potentiometer for different measurement distances

The arrangement for continuous measurement of the variation in distance between measurement points is esp. for monitoring workings in coal mines. It contains a cable and drum with a toothed disc on the drum axle engaged by the clamp spring gear. A potentiometer driving a precision voltage-to-frequency converter is also driven from the same shaft. It is a compact system which can be adjusted to the required measurement length without great effort and under comparable measurement conditions. The cable drum (6), spring (13), cable drum shaft (10) end plates (4,31) and the spring shaft (12) have the same dimensions for all the distances to be measured. The potentiometer (20) and/or the associated gearwheels (32,33) which are externally mounted, can be changed for different measurement distances.