Improvements in or relating to escapement or driving mechanism having relatively rotatable and oscillatable magnetically coupled parts

摘要

759,581. Magnet couplings. HORSTMANN CLIFFORD MAGNETICS, Ltd., and CLIFFORD, C. F. July 16, 1951 [July 15, 1950], No. 17748/50. Class 35. [Also in Group XVIII] The isochronism of a magnetic escapement or driving mechanism of the type described in Specification 596,216, [Group XVIII], is improved by providing between the rotary and oscillatory parts a magnetic coupling of varying reluctance. In the first example, Fig. 1a, the escape wheel 11 which is controlled by the oscillator 14, 15 is made thinner at the centre of the wavy track than at the apices. In another example, Fig. 1b (not shown), the wavy track of the escape wheel is made narrower at the centre than at the apices. The thickness of the escape wheel at the wavy path and/or the width of such path may vary gradually. In another example, Fig. 2, compensation for magnetic forces which adversely affect isochronism is provided by a U-shaped magnetic member 29, 30 which may be adjustable and is located adjacent the pole pieces 25 of the oscillator 24 carried by a resilient spring blade 26. The member 29, 30 may be replaced by two pins 30a, Fig. 4. Specifications 570,143 and 644,000, [both in Group XVIII], also are referred to.