GB1286015A - A watch movement comprising a device for undirectionally blocking a ratchet wheel - Google Patents

Abstract

1286015 Watches A SCHILD SA 14 Sept 1970 [15 Sept 1969] 43871/70 Heading G3T A click device for providing limited recoil of a ratchet wheel 1 when the latter is rotated in the direction of arrow 18 to wind a watch mainspring comprises a member 6 having an arm 11 terminating in a circular head 13 by means of which the member 6 is pivotally mounted within a recess 5 provided in barrel bar 3. The member 6 has an asymmetric tooth 15, which engages toothing 16 of the ratchet wheel 1 to prevent reverse rotation of the latter, and a resilient arm 9 terminating in a head 8. On winding the mainspring, the member 6 is rotated in a clockwise direction until head 8 is brought into contact with toothing 16, whereupon continued rotation of the wheel 1 is permitted by the resilience of the arm 9. As the winding torque is relaxed, the member 6 returns to its blocking position, permitting a recoil of the ratchet wheel 1 equivalent to at least two teeth of the latter. The engagement of the ratchet tooth 15 in the toothing 16 is limited by a projection 12 on the member 6 and a co-operating portion 14 of the recess 5, thus preventing jamming. This limitation may alternatively be provided by an arcuate surface (28), Fig.7 (not shown) on the click member engaging the tops of three teeth 16. The head 8 has an aperture 17 by means of which the member 6 may be rotated manually to free the ratchet wheel 1. In a further embodiment, the resilient arm (49) Fig.8 (not:shown) of the click member lies below the teeth 16.