GB548669A - Improvements in or relating to driving mechanisms particularly for watches or clocks - Google Patents

Abstract

548,669. Driving mechanisms. JACCARD, P. R. April 17, 1941, No. 5011. Convention date April 1, 1940. [Class 139] [Also in Group XXVI] A driving mechanism, especially for watches or clocks, has an auxiliary spring 20, Fig. 4, or 26, Fig. 5, for transmitting a constant driving torque to the driven element, said auxiliary spring forming a driving connection between on the one hand, a rotatable supporting member 10 subjected to the action of the driving motor 2 and carrying a movementbraking disc 18 connected to an epicyclic gear for imparting rotation to the disc upon rotation of the supporting member 10, and on the other hand a wheel 19 connected to an escapement, and is characterised by the feature that the axle 4 of the supporting member 10 is rotatably mounted in the frame of the mechanism and carries said wheel 19 connected to the escapement, the supporting member 10 and said wheel 19 being rotatable relatively to each other. As shown in Fig. 1, the main spring 2 drives the supporting member 10 through gearing, and wheel 19 is connected by gearing to the escapement of a watch 8. A pinion 11 on member 10 rotates round a stationary gear 12 fixed to the frame, and through a gear train, not shown, rotates braking disc 18 rapidly as member 10 is rotated by the main spring. Post 10c on member 10 acts on auxiliary spring 20 carried by wheel 19 to urge the wheel in the direction shown in Fig. 4. Wheel 19 is controlled by the watch escapement through pinion 5 and so rotates intermittently, the part 21 in turn braking and releasing braking disc 18 as spring 20 bring them into contact and allows them to separate. In a modification, shown in Fig. 5, member 10 has a projection 22 to which are pivoted levers 23, 24, while a tension spring 26 joins pin 27 on wheel 19 and arm 28 pivoted on member 10. With member 10 stationary, and member 19 rotating under the influence of spring 26, pin 25 operates lever 24 to lift lever 23 from braking disc 18, which then rotates to allow member 10 to rotate again, thus allowing lever 23 to return to press again on disc 18. Teeth 30 on member 28 mesh with gear 31 rigid a button 32 on axle 4. Button 32 can be rotated to vary the tension of spring 26. In a further modification, (Fig. 6, not shown), the arm 28 is replaced by a lever rocked periodically by a cam in the gear-train between pinion 11 and disc 18. In yet another modification, (Fig. 7, not shown), the braking effect is produced by having gears mounted in both members 10, 19 so that relative movement tilts the axles causing the gears to rub against member 10. Instead of being connected to an escapement, the wheel 19 may be connected to a movement regulating device effecting a continuous movement, such as a centrifugal governor or a flywheel. Alternatively, the wheel 19 may itself constitute a flywheel. In such a case, there will be a continuous slipping between the two contacting surfaces.