GB1315689A - Timepiece mechanisms - Google Patents

Abstract

1315689 Clocks and watches FABRIQUE D'HORLOGERIE CHARLES TISSOT & FILS S A 23 Nov 1970 [22 Nov 1969] 55680/70 Heading G3T In a timepiece having an electromagnetically maintained balance 1, 2 driving a lever 5, one end 11 of which alternately advances toothed wheels 12, 13 and hence a wheel 14 which may be a seconds wheel, the wheel 12 is rotatably mounted on a rocking lever L and may thus be moved into a second position out of reach of the lever 5 to permit hand setting without interrupting the motion of the balance. The lever L is mounted on a stationary pivot 23 and comprises resilient arms 21, 22 of which the latter blocks the wheel 14 when the lever L is in the second position. The arm 21 abuts a pivot spindle 24 of a control lever L 1 and biases the wheels 12, 13 into meshing engagement. The control lever L 1 has an end l which is engaged by a setting stem 31, inward displacement of the stem bringing a stud 27 on the lever L 1 into contact with the arm 22 to move the wheel 12 into the second position. In this position, the wheels 12, 13 remain slightly meshed to facilitate re-engagement. Reverse rotation of the wheels is prevented by a freely pivoting pawl 15, and the lever 5 carries a magnetisable block 9 to hold the lever alternately against banking pins 10a, b which are fixed to a permanent magnet 10. The timepiece also comprisesa snap-on, frictionally mounted cannon pinion to permit setting while the wheel 14 is blocked. An alternative arrangement is envisaged in which the wheel 12 is mounted on an lever which is pivoted about the shaft 19 of the wheel 13 so that the wheel 12 moves about the latter in a planetary manner. The pawl 15 is then replaced by a conventional pawl and the wheel 12 is biased into engagement with the wheel 13 by a spiral spring. The stem 31 may be provided with an abutment to block the wheel 14 directly.