GB807672A - Improvements in and relating to selective positioning mechanisms - Google Patents

Abstract

807,672. Electromagnets. COLLINS, C. A. HENN-. July 6, 1955 [April 9, 1954], No. 10460/54. Class 35. [Also in Groups XXXVIII and XL (b)] In a selective positioning means in which the position of a controlled member is obtained by the algebraic sum of the movements of serially connected individual members, a first member movable by electromagnetic means to assume a position in response to a signal is permanently connected to form a rigid drive connection with a second member which transfers its movement to a third member and electromagnetic means carried by the second and third members is operated conjointly in response to a signal to displace the third member relative to the second member to assume a further desired position, the third member being connected to the controlled member either directly or through further members similar to the said second and third members. In the arrangement shown in Fig. 1, the armature 13 is located with its ends adjacent arcuate pole-pieces 11, 12 each extending over 90 degrees and a reversal of the current through the winding 14 rotates the armature 13 through 90 degrees. The armature 13 is directly coupled to a ring 16 carrying polepieces 17, 18 extending over 135 degrees. The armature 19 is connected to a type-wheel 24. The operation of the armature mechanically rotates the ring 16 and armature 19 through 90 degrees and a reversed current through winding 23 effects an additional rotation of 45 degrees. In a modified arrangement, Fig. 2, a sleeve magnet 27 is slidable in a fixed core 26 having shoulders 31, 32 of opposite polarities. The magnet 27 is coupled by a shaft 34 to a magnetic core 33 slidable on the shaft extension 39 of a sleeve magnet 37 co-operating with polepieces 35, 36 formed on the core 33. The shaft 39 is connected to the member to be positioned and the movement effected by the sleeve magnet 27 is arranged to be twice that of the magnet 37 so that the shaft 39 can take up four positions corresponding to 0, 1, 2 or 3 units of movement. A modification to obviate the risk of the magnet sticking to the polepieces and in which the shouldered polepieces of the core are extended to overlap the end portions p1, p2 of the sleeve magnet is indicated in Fig. 3 (not shown). Specification 745,496 is referred to.