GB596216A - Improvements in or relating to escapement mechanism - Google Patents

Abstract

596,216. Escapement mechanism. CLIFFORD, C. F. April 18, 1939, No. 11682. [Class 80(iv)] [Also in Group XVIII] A magnetic escapement comprises complementary relatively oscillating and rotating members on one of which there is at least one polar formation and on the other of which there is provided a wavy magnetic path and in which either or both of the twc members is or are permanently magnetised whereby torque applied to the rotary mem ber impulses the relative oscillatory movement and produces escapement by causing the polar formation to follow the said wavy path while magnetically locked thereto. A pendulum a, Fig. 1, suspended on a knifeedge fulcrum b carries a hollow non- magnetic block c within which is fixed a magnetic conductor d of substantially sine wave form and having eight complete waves. An eight-pole star magnet e is rotatably mounted within the conductor d each alternate N. and S. poles of the magnet being adjacent corresponding points on each wave of the conductor d. The star magnet e is driven by suitable means but will only rotate when the pendulum a oscillates because of the magnetic lock between the poles of the magnet e and the conductor d. The star magnet e will rotate at a speed corresponding to the natural frequency of oscillation of the pendulum a since the poles of the magnet e follow the conductor d so stimulating oscillation of the pendulum a. In another embodiment, Fig. 2, the star magnet is replaced by a bar magnet h which co-operates with a stationary conductor f. In this case the-bar magnet h rotates and oscillates. In further embodiments, not shown, the pendulum carries two poles which co-operate with a rotating member having a magnetic conductor of wave form. In a further embodiment, Fig. 6, the device comprises a pair of permanent magnets n secured by opposite poles to a magnetically conductive base and to each free pole is attached a reed n<SP>1</SP>. The reeds n<SP>1</SP> which have flux induced in them by the magnets n cooperate with a wavy magnetic conductor o which thereby rotates at a speed controlled by the natural frequency of vibration of the reeds. In other embodiments, not shown, the polar formation rotates within an oscillating wavy magnetic conductor. The wavy conductor path may be formed as shown in Fig. 11.