Vehicle speed or revolution rate indicating instrument - has indicator needle position motor and needle position slip contacts

摘要

The device is for displaying measurement parameters, esp. vehicle speed or engine revolution and has a circuit evaluating the measurement transducer signal and driving a display showing the results discontinuously. It is a robust durable simply contracted device which is very economical to produce. An electric motor driven by the evaluation circuit output positions the indicator needle according to the instantaneous value measured. The electric motor, which can rotate in either direction, drives the needle, which is attached to a disc, either directly or via gears. At least one measurement value, pref. zero, is adjustable absolutely. The motor drive may be controlled via the contact between the moving indicator needle and slip contacts on its path of motion and connected in the motor current circuit.