GB661127A - Typewriter having a variable step-by-step spacing movement - Google Patents

Abstract

661,127. Typewriters. TORPEDO WERKE AKT.-GES. FAHRRADER U. SCHREIBMASCHINEN. April 11, 1949 [April 13, 1948], No. 9809/49. Class 100 (iv). In a feed arrangement for the paper carriage of typewriters, comprising an escapement lock having a fixed pawl and a loose pawl for adjusting a ratchet wheel to perform a spacing operation, a back-space pawl for the ratchet wheel, and an adjustable abutment for the loose pawl, for varying the length of the spring movements, the loose pawl and the back-space pawl are each pivotally mounted on a pin constituting one element of a pin-and-slot connection which permits movements of the pawl relatively to the ratchet wheel to ensure a substantially constant depth of engagement of the pawl with the ratchet wheel throughout the spacing movement. On the escapement lock place 1 are mounted the fixed pawl and the loose pawl 3, the latter being mounted on a pin 5 and guided thereon by a curved slot 22. On release from .the ratchet wheel 4, the pawl 3 swings anticlockwise and is also moved to the left by a spring 6, and thus towards the ratchet wheel so as to make firm engagement therewith when racked into operative position by the plate 1. The amount of movement of the pawl, and hence the spacing movement of the ratchet wheel when it swings the pawl back until its nose 20 bears against a fixed abutment 21, is controlled by the position of the adjustable abutment 7 which limits the leftward movement of the pawl. The abutment 7 is rocked for longer spacing by means of a link system, including a spring 10, actuated by a comb bar pivotally mounted below the key levers and having teeth cooperating with the type levers of characters requiring longer spacing and with the shift-key and shift-lock levers, the amount of swing of the abutment 7 varying according to the disposition of the comb teeth. In order to reduce the amount of swing of the pawl 3 to the left of the vertical plane through the axis of the ratchet wheel, the abutment 21 is arranged so that the operative face 23 of the pawl lies slightly to the right of the plane in the initial position. In order to avoid the jamming in the ratchet wheel of the finger of the back-space lever when long spacing is used, the back-space lever is also guided on its mounting pin by means of a slot and is spring-urged towards the ratchet wheel so that the latter can move the lever against the spring action as soon as the finger encounters the bottom of a tooth gap.