Patent GB-216261-A (GB)
Title: Improvements in case shifting mechanism for typewriting machines
IPC: B41J25/24
Filed: 1923-03-19
Abstract: 216,261. Marks, E. C. R., (Corona Typewriter Co., Inc.). March 19, 1923. Case, carriage, and platen shiftmechanisms; shiftkey actions; typelever machines.-In typewriter casechanging mechanism in which the platen and type are mounted on supports one of which is movable, anti-friction rolling elements are arranged between both faces of the movable support and stationary raceways, those on one face being arranged centrally to the support and spaced apart in the direction of its movement, and those on the other face being spaced apart transversely to this direction. Retainers are provided to maintain the rolling elements in the same relative positions. In the application to a small folding typewriter with front-strike typelever action, the type segment 21. Figs. 4 and 8. is carried by a flat. vertical, sheet-metal plate 8 movable edgewise between a single fixed rear plate 5 and two separate plates 14 on arms 15 of fixed brackets 16. Two balls 10 spaced apart vertically on a line at the centre of the plate 8 are arranged in raceways formed by bevelled vertical slots 7, 9 in the plates 5, 8, and two balls 18, Fig. 8, spaced apart horizontally on a line passing midway between the balls 10 are arranged with limited lateral play in raceways formed by depressions between slots 12 in plates 5, 14. The arms 15 are resilient and flex towards, and may be adjusted by bolts 20 towards, the plate 8 to compensate for wear and inequalities. The plate 8 is thus guided for vertical movement, and forwards and sidewise movements of the plate are prevented by stops 23 on the bracket 16. The balls 10, 18 are maintained in the same relative position by retainers 24, Figs. 8 and 15, each comprising a sheet metal ring surrounding the ball with diametrically opposite projections carrying lugs 26, one lug pivotally engaging a horizontal slot 27 in the plate 8 and the other a horizontal slot 28 in plates 14 or plate 5. The end positions of the segment are determined by stops 55, 58 each comprising a screw with lock-nut carried by .a projection on the plate 8. The segment is normally held in its upper position by a spring 38 connecting arms 37 of two symmetrically arranged, three-armed, transverse levers 32 pivoted at 31 to the plate 5 and at 35 to the plate 8. Each pivot 31 comprises a slotted extension of the plate 5 detachably engaging a recess with rounded projection 42 in the lever 32 near the arm 37. The pivots 35 comprise a slotted extension of the plate 8 detachably engaged by hook-shaped ends 36 of the levers 32. In the case of multiple-shift mechanism, an intermediate segment-stop 61 comprises a screw and lock-nut carried by a spring-pressed, horizontal metal bail 62 carried by pivoted side arms. A pair of shift-key levers is provided at each side of the machine and guided in combs 44 on the brackets 16. One lever 46 of each pair operates on one of the levers 32 to lower the segment to the intermediate stop 61, whilst the other lever 48 of each pair operates on one lever 32 to lower the segment against the stop 58 and withdraws the stop 61, the bail 62 being rocked to inoperative position by the engagement of a projection 69 on the lever 48 with a lug 68 carried by the bail 62. The projection 69 is of bendable sheet metal to allow adjustment of the normal position of the stop 61. The bail 62 is resilient and the part 59 of the plate 5 carrying the stop 58 is normally just clear of the bail 62, but immediately beneath it. The shift-key levers are fulcrumed at a point between the levers 32 and the keys by means of hooks 50, Fig. 6, on the leversengaging slots in brackets 51, and are raised by springs in front of these pivots. Means for locking the segment in its shifted positions may be provided.