GB272285A - Improvements in line-spacing mechanism for typewriting machines - Google Patents

Abstract

272,285. Fairweather, W. C., (Underwood Typewriter Co.). March 9, 1926. Line-spacing mechanism. - The line-spacing pawl is pressed into contact with a ratchet-wheel on the platen by a spring co-operating with an abutment arranged to increase the pressure at the beginning of the stroke, overthrow of the platen being thereby prevented; the ratchet-wheel may co-operate with a detent releasable by a cam so arranged that if the detent is in released position it is automatically restored when the line-spacing mechanism is operated, In the mechanism shown in the Figure, a slide 13 operated by a lever 10 and carrying the pawl 15 is provided with a spring 27 which presses on the pawl and rides under an abutment 29 so arranged that a tooth 17 on the pawl is pressed firmly into engagement with the ratchet-wheel 18 at the beginning of the stroke. At the end of the stroke the spring is disengaged from the abutment and an incline 32 arrests and jams the pawl by contact with an incline 31 thereon. The slide is connected to a returning-spring 25 and has a screw 23 engaging a guide-slot 24 in the end plate 21. Spacing is regulated by means of an adjustable shelf 34 on which the pawl normally rests. The shelf is formed on an arm 33 pivoted on the platen shaft 20 and adjustable by a knob 35, a yielding detent 37 retaining the arm in adjusted position. A roller-detent 39 engaging the ratchet-wheel is carried by a spring arm 40 and is releasable by a cam 42 on a finger-lever 41. If the line-spacing mechanism is operated when the finger-lever is in the released position, the slide 13 engages the finger-lever and the detent is automatically restored,