GB764450A - A battery operated electromagnetic wrist watch - Google Patents

Abstract

764,450. Watches. HAMILTON WATCH CO. Jan. 24, 1955 [Feb. 12, 1954], No. 2033/55. Class 139. In an electric watch the balance is maintained in oscillation by the inter - action between a coil carried by the balance and a magnetic field provided by two permanent magnets, the coil being periodically connected to a battery within the watch casing. The balance staff 57, Fig. 3, is supported between the balance cock 53 and a plate 45 in bearings 56, 58. The plate 45 supports straight and curved permanent magnets 48, 49, Fig. 4, the ends of which are bridged by a shunt 50 supported on non- magnetic bridges 50' to provide magnetic fields 51, 52, Fig. 12, through which passes a coil 65 carried by the balance 61. The balance 61 is provided with screws which counter-balance the weight of the coil 65 one end of which is connected to the balance and the other end of which to a nut 92, Fig. 3, which receives a screw 93 connected to a contact strip 68 supported by an insulated sleeve 69 on the roller 63. A bridge 77, Fig. 2, supported by the plate 45 and insulated therefrom is connected by a wire 79 to a battery 46 contained in a recess in the plate 45. A pin 73, Fig. 10, is adjustably supported at the end of the bridge 77 and carries a coil spring 72 the end 71 of which extends towards the balance staff. A spring contact arm 70 is connected to the end 71 of the spring 72. The roller 63 carries a jewel pin 83 which as the balance swings counter-clockwise meets the extension 71 of the spring 72 and pulls the end of the contact arm 70 into engagement with the contact strip 68 thereby energizing the coil 65 and impulsing the balance. The arm 70 does not meet the contact strip 68 as the balance swings clockwise. As the balance swings counterclockwise and clockwise a pin 84, Fig. 4, depending from a roller 62 alternately stepson one of two intermeshing gears 85, 86 by half a tooth pitch. The gear 85 has a pinion 23 which drives the train of gears to the hands 18, 19, 20, Fig. 3.