GB1214130A - Improvements in apparatus for producing motion of a workpiece - Google Patents

Abstract

1,214,130. Rear-view mirrors. H. J. COSH. 23 June, 1969 [25 June, 1968; 5 Sept., 1968; 16 Dec., 1968], No. 31537/69. Heading B7J. [Also in Divisions F4 and H1] As shown, Fig. 1, the angular position of a mirror may be adjusted in a series of discrete steps by means of an actuating mechanism comprising four electromagnets 21 mounted on a common yoke 27 which engages a half ball 31 on a fixed shaft 13, the cores of the electromagnets projecting through apertures in an aluminium plate 23 and being provided with polepieces. 24. A primary armature 33 having surface layers 36 of a material having a high coefficient of friction, e.g. rubber, is mounted on an extension 30 of shaft 13 so that it can move axially and pivotally but not laterally, and is biased by a spring 37 into contact with the back 34 of the mirror which is supported in spaced relation to plate 23. A secondary armature 43 having a surface layer of a friction material, e.g. an abrasive material, is located between the polepieces 24 with its edges laterally spaced therefrom and is supported by flat springs (49). The plate 23 and secondary armature 43 are provided with recesses 47, 48 respectively, located symmetrically between each pair of electromagnets and containing ball bearings 46. The edges of the armature which are adjacent to the polepieces may be coated with a non-magnetic material to prevent sticking. In operation a pair of adjacent coils are energized attracting the secondary armature 43 laterally into contact with their polepieces 24. This movement causes the secondary armature to ride up on the ball bearings 46, Fig. 5 (not shown). All four coils are then strongly energized and the main armature is attracted towards the polepieces of the magnets into contact with the secondary armature 43 to which it applies a pressure which causes lateral forces to be generated between the plate 23 and the secondary armature 43 due to the action of the ball bearings on the inclined faces of the recesses. Since the primary armature 33 cannot move laterally and is in frictional engagement with the secondary armature 43, the lateral forces cause a lateral movement of plate 23 so that the magnet assembly and the mirror are tilted relative to their initial position, Fig. 6 (not shown). The coils are then deenergized to release the primary armature 33 into contact with the back of the mirror to maintain this in its new position. By applying a number of such steps in sequence using appropriately selected pairs of coils the angle of the mirror can be adjusted in any direction to the required extent. In a modification, Fig. 7 (not shown), a wing mirror of a vehicle is supported on a ball joint and is provided with a plurality of interleaved clutch plates which are pressed into engagement by a spring when the electromagnets are unenergized but are released for relative lateral movement when the armature (83) is attracted by the electromagnets. A device for the lateral movement of a workpiece in one dimension, Fig. 8 (not shown), comprises a pair of electromagnets (100) between the polepieces (126) of which is located a bowed spring member (117) having armature members (120) at its ends which are adjacent to the polepieces (126). The workpiece (116) is supported above the electromagnets by a pair of leaf springs (125) and is retained by a plate member 102. When one of the magnets is lightly energized the adjacent armature of the spring member is attracted into contact with its polepiece. Both magnets are then energized to attract the workpiece which presses on the spring member which spreads out, but since one end is in contact with one of the polepieces the spring member moves laterally carrying the workpiece with it. The magnets are then deenergized and the workpiece is released. The spring member is re-centred by a coil spring arrangement. Further magnets may be provided to permit lateral movement in two dimensions. The device may also be used to provide remote control of vehicle headlamps. Control may be effected manually or by electronic switching equipment.