A horological instrument such as a watch includes an indexing mechanism or dial train drive for transmitting power from an oscillating balance wheel to an index wheel. The index wheel drives the gear train of a watch. The balance wheel oscillates a lever between two end positions and one or more pins mounted on the lever alternately engage the teeth of the index wheel stepping the index wheel in the desired direction. The index wheel is held in a rest position at the end of each step by indexing magnets which are arranged to exert a predetermined torque on the wheel and to hold the lever in its banking or end positions.
A counting mechanism for timepiece having a bidirectional step by step motor, in which the rotor of the said motor cooperates directly with a counting wheel in such a way as to drive it only in one direction, this counting wheel being submitted to the action of a magnet which determines, at each step, its position while cooperating successively with each tooth of its toothing.
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.
A timepiece has a counting mechanism for counting the oscillations of the oscillating regulating member. The counting mechanism includes a plastic block with a retaining pawl and a driving pawl embedded within it. The block has a notch whose two walls serve to limit the movement of a first portion of the driving pawl which is embedded by one extremity in the block and passes through the notch to an elbow formed in the driving pawl which cooperates with the oscillating member to drive a ratchet wheel by a second driving portion of the driving pawl. The retaining pawl has one extremity embedded in an elastic portion of the block and the other cooperates with the ratchet. The block has an eccentric member abutting the elastic portion to adjust the position of the retaining pawl.
A stepper drive for a step-type transformer has an upper geneva wheel rotatable about a wheel axis, a lower geneva wheel spaced below the upper wheel and also rotatable about the axis, and a driver rotatable about a driver axis adjacent the wheels and having an upper abutment engageable with the upper wheel and a lower abutment engageable with the lower wheel and offset by about 180.degree. relative to the driver axis from the upper abutment. A selector abutment is provided on the upper wheel offset from the axis thereof. A selector lever pivotal about a selector axis offset from the wheel axis is engageble with the selector abutment in end positions of the upper wheel. A blocking plate shiftable radially on the lever between an actuated position and an unactuated position is urged by a spring into the unactuated position. A blocking element on the plate is positioned in the path of the upper abutment of the driver in the actuated position and out of the path of the upper abutment of the driver in the unactuated position. The driver is rotated about its axis to displace the upper drive wheel between its end positions, and engage the selector abutment in the one end position of the upper wheel against the blocking element to shift it into the actuated position on such engagement.
