Abstract: Apparatus for scanning the relative position of a preselector counter mechanism which includes a plurality of digital discs having radial cams rotated in accordance with the setting of a preselected numerical value on the counter, with each of the radial cams being provided with a scanning arm adapted to initiate a switching operation upon reaching a preselected stage of the counter mechanism, is provided with a plurality of counter wheels each adapted to be set to a pre-selected value with an analogue metering value cam in the shape of an Archimedean spiral being affixed to each of the counter wheels. Each of the counter wheels and the metering value cams is arranged to represent a decade of a decimal system numerical value. Indexing pinions gear each of the counter wheels and the metering value cams with those representing a next adjacent decade.

Abstract: In a setting device for presettable counters, a number of indicating rollers are arranged with symbols on their circumferential peripheral surfaces. Connected to each indicating roller is a ratchet wheel and an adjusting wheel. A switching device for each roller permits it to be moved in a step-by-step manner and otherwise to be locked in position. The switching device includes a switching pawl for engaging the ratchet wheel and moving the roller, a fixing lever for locking the adjusting wheel and roller in position, a control pawl and a key for displacing the control pawl. The control pawl is spring-biased against the actuating movement of the key. The control pawl displaces the switching pawl and the fixing lever in response to its displacement by the key.