GB191003215A - Improvements in Typewriting Machines. - Google Patents

Abstract

3215. Turner, S. W. Feb. 9. Letter-spacing mechanism.-Relates to escapement mechanism particularly for use in machines for writing Turkish and Arabic. (1) For reversible spacing, in conjunction with two adjustable racks on opposite sides of the escapement pinion c, Figs. 1 and 10, the guide-pulley d<3> for the spring- drum cord d<2> is attachable alternatively on the carriage or on the main frame. The two racks a, b are pivoted and pressed towards the pinion c by springs a<7>, b<5>, and are adjusted by means of thumblevers a<3>. Pivoted detents a<6> hold the thumb-levers in position to maintain the corresponding rack inoperative. The thumb-lever for the rack a is provided with a pin a<5> engaging a curved arm a' on the rack. The thumb-lever for the rack b engages a rib on the rack. (2) For differential spacing in two values, the escapement comprises fast and loose ratchet-wheels e, f, Figs. 1 and 5, connected by a spring e<4>, a co-operating fast dog e' rocked by a universal bar h' and normally engaging the loose wheel f, and an auxiliary pivoted dog e<2> rocked by a second, universal bar j and serving to limit the advance of the loose wheel f to determine the smaller space movement of the fast wheel e. Some keylevers actuate the bar h' only, for the larger space, and the others actuate first the bar and then the bar h<2>, for the smaller space. The relative movement of the wheels e,f is determined by stops, for example a screw g<1> in the shaft g and a slot f<2> in the boss of the wheel f. When the fast dog e<1> moves from the wheel f to the wheel e, the wheel f advances under the action of the spring e<4>, either to the full extent determined by the rear edge f of the slot f<2>, or to a less extent determined by the pivoted dog e<2>. When the dog e<1> returns to the wheel f, the wheel e advances a corresponding extent to bring the stop g<1> up to the front edge of the slot f<2>.