GB644000A - Improvements in or relating to escapement mechanism - Google Patents

Abstract

644,000. Escapements. CLIFFORD, C. F. Feb. 12, 1947, No. 4109. Addition to 596,216. [Class 139] The magnetic escapement of the parent Specification is modified by the provision of a wavy magnetic path which is not endless. As shown in Fig. 1 the poles b of a rotary escape wheel a co-operate magnetically with tongues in split-rings c\ c<SP>2</SP>, c<SP>3</SP>, c<SP>4</SP> carried by an oscillating member. In another embodiment (Fig. 3, not shown) the invention is applied to a lever escapement, the lever of which is provided with a short wavy magnetic path which cooperates with studs on the escape wheel. In another example the split rings c\ c<SP>2</SP>, c<SP>3</SP>, c' are provided with two diametrically opposite set of tongues as in the first example and are disposed between two polar escape wheels mounted on the same shaft. In another embodiment, Fig. 6, a drum 6b on the balance staff is provided with a wavy path 6c with which co-operate soft iron pins 6h on two rotating discs 6f of transparent plastic. The poles 6i of a permanent magnet provide the magnetic field for the path 6c and the pins 6h. At the top the balance spindle may have a small pin of magnetisable material which pin may be bent more or less into the magnetic field and thereby modify its reluctance and effect a control of the speed of oscillation of the path at varying amplitudes. The drum 6b may be provided with non-magnetic laminations 6p to act as a mechanical obstruction to the pins 6h so preventing momentary excess movement of the wheels 6f. In a further embodiment, Fig. 7, a pendulum 7a has at its upper end a U-shaped permanent magnet 7b. Secured to the poles of the magnet are wavy soft iron paths 7e, 7f which cooperate with soft iron pins 7i carried by the escape wheel 7g. A pin may be fixed between the poles of the magnet to provide a mechanical lock for the escape wheel (Fig. 7A, not shown). In another embodiment (not shown) a vibrating reed has an inertia weight in the form of a permanent magnet which carries a raised wavy soft iron path which co-operates with pins on the periphery of an " escape drum " which also carries additional pins which abut the path to provide a mechanical safety lock. In another example (Fig. 9, not shown) a balance wheel carries the wavy path which co-operates with pins on the escape wheel and a permanent magnet again provides the magnetic field. In a further example, Fig. 10, the wavy path is placed on the escape drum 10a and co-operates with the poles of an oscillating ring magnet 10d.