GB773379A - Improvements in or relating to escapement regulators - Google Patents

Abstract

773,379. Watch bearings. JUNGHANS, H., and JUNGHANS AKT.-GES., GEB. Nov. 3, 1954 [Nov. 3, 1953], No. 31843/54. Class 12 (1). [Also in Group XVIII] In a time-piece, the pressure of the balance staff in the bearings is relieved by permanent magnetic means. The balance staff 12, Fig. 1, has thin end pivots 12a and extends between bearing plates 10, 11. A permanent magnet disc 17 is secured to the staff 12 and co-operates with a fixed permanent magnet ring 19 to relieve partly or completely the axial load on the bearing. The thickened shank 12b of the staff 12 extends into bores 10a, 11a in the plates 10, 11 whereby excess transverse movement of the staff 12 due to shock is prevented. Excessive axial movement of the staff 12 is prevented by stops 20 on either side of the balance 16. The cooperating magnets may be of the same or opposite polarity and their relative positions are chosen accordingly. The magnets may be of a metallic, partly metallic or non-metallic substance. A damping disc 34, Fig. 2, of a substance having a low electrical resistance may be located adjacent the magnet 31 on the balance staff. The balance staff may have conical bearing ends. If desired the balance itself may be in the form of a permanent magnet. In another embodiment, Fig. 4, the balance staff 53 is hollow and is mounted on a steel wire damped between plates 50, 51. A cylindrical magnet 57 or member of magnetic material fixed to the staff cooperates with a coaxial fixed magnet. In an example (not shown) a ring of ferromagnetic material is fixed to the balance staff and cooperates with a horseshoe magnet. In the example shown in Fig. 8, the balance staff 100 is supported by the attraction between a cylindrical permanent magnet 101 secured to the top of the staff and a ring permanent magnet 102 fixed to a plate 103 which has a bearing 103a for the thin upper pivot of the staff 100. The thin lower pivot 100b of the staff 100 projects into a guide bore 104a in the plate 104 to prevent wandering of the bottom end of the staff. The staff 100 may, as shown, carry a stabilizing weight 107. Wandering of the bottom end of the staff may be prevented by having a pointed magnet at the lower end of the staff and' a stationary coaxial magnet on the adjacent frame plate. In another example, Figs. 12 and 13, the hollow balance staff 153 is mounted by bearings 154 on a wire 151 stretched between the limbs 144a, 144b of a U-shaped frame 144 made of a metal or a synthetic resin. The escape wheel 142 is in a plane at right-angles to the balance 158 and the escape lever is therefore cranked. A cylindrical permanent magnet 162 is cemented to a sleeve 161 fixed to the staff 153 and co-operates with a permanent magnet 163 cemented in a bearing casing 152 riveted to the limb 144b of the frame 144. The permanent magnets may bo partially or completely enclosed in a housing and a pivoted regulating lever one arm of which may be more or less introduced into the air gap between the magnets may be provided, Figs. 14 and 15 (not shown). The regulating lever is made of a substance of low electrical resistance.