Les Fabriques D'assortiments Reunies

Les Fabriques D'assortments Reunies

Christian Faivre

Roger Buhler

An energizing circuit for an electric motor, driving a clockwork of a timepiece, includes a stator coil coacting with one or more magnet pairs on an associated rotor whose periodic alignment with the coil induces therein a train of monitoring pulses with a frequency proportional to the motor speed. The monitoring pulses are amplified and fed back to the coil, as driving pulses, through a coincidence gate which is opened or closed under the control of a speed-sensing network including a crystal-controlled oscillator whose output wave, stepped down in a frequency divider, is a series of timing pulses fed to a pulse counter which is reset by the monitoring pulses and whose count, therefore, varies inversely with the motor speed. Through a logic circuit and a pair of cascaded flip-flops, the transmission of driving pulses to the coil is inhibited when the count falls short of a lower limit -- indicative of excessive motor speed -- but is allowed to proceed when the count surpasses an upper limit representing an insufficiently low speed. In the range between these two limits, the counter blocks or unblocks the transmission of a driving pulse in dependence upon the relative phasing of the monitoring pulses from the motor and a sequence of reference pulses of fixed cadence, equal to a fraction of the timing-pulse frequency, derived from the frequency divider. The monitoring pulses and the reference pulses are supplied through an anticoincidence network, including a pair of binary memories, to a reversible pulse counter delivering a phasing signal to the logic circuit.

Digital system for stabilizing the speed of a clockwork motor

An escapement-type drive mechanism for watches and the like comprises an escapement wheel formed with a circumferential array of teeth spaced apart by respective radial slots and having displacement faces inclined to respective radii. An angularly oscillatable inverse anchor-shaped lever is engageable with the wheel for intermittently rotating it. The lever is formed with a pair of spaced-apart pallets (pins) mounted for lost motion on the lever and alternately engageable with the faces and receivable in the slots to step the wheel upon angular oscillation of the lever. Magnetic means on the lever yieldably biases each of the pallets in a respective direction of its lost motion relative to the lever.

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Morteau, France

Christian Faivre