GB126240A - Improvements in Line-spacing Mechanism for Typewriting Machines - Google Patents

Abstract

126,240. Fairweather, W. C., (Underwood Typewriter Co.). Oct. 15, 1918. Line-spacing mechanism. -In mechanism in which two ratchet-wheels having different numbers of teeth are provided, a single pawl is arranged to be shifted into engagement with either ratchet-wheel, and individual detents, which may be controlled by the pawlshifting device, are provided for the ratchetwheels. As shown, a dog 5 can be shifted laterally by a hand-lever 14 to bring a tooth 13 on the dog into register with either of two ratchet-wheels 1. 2 secured to the platen-shaft 3, the wheel 2 having a greater number of teeth than the wheel 1. The dog is pressed downwards by a broad spring 5<a>, and a stop 36 is provided for arresting the dog. The dog is mounted on a pin 6 secured to a slide 7 which is operated by the usual linespacing lever and returning-spring 11. The handlever 14 is pivoted at 15 and provided with two depending pins 17 which straddle a rib 18 on the dog and engage a humped spring 19 for retaining the parts in the set position. During part of the travel of the dog, the tooth 13 is held out of engagement with the ratchet-wheels by a support 32 which can be adjusted to vary the line-spacing. The support is secured to a slide 28 which can be moved to the front or the rear by a hand-lever 29, and is held in the set position by a spring detent 33 engaging recesses 35. The support is of sufficient length to engage the tooth in either of the lateral positions of the dog, and is preferably reduced in width at the part that is over the ratchet-wheel 2 to compensate for the difference in pitch of the teeth on the ratchet-wheels. The hand-lever 29 is set with reference to indicating- numerals 38 on the hand-lever 14, the numerals being arranged in two columns which are visible, a column at a time, through, a slot 39 in the casing 40. The ratchet-wheels 1, 2 are provided with detents 20, 21, respectively, arranged so that the operative ratchet-wheel is engaged by its detent. the other detent being diesngaged. The detents consist of levers, which are pivoted on the pin 25 and are provided at the top with rollers engaging a cam-slot 26 in the hand-lever 14. The detents are engaged by springs 23 and are provided with rollers 22 for engaging the ratchetwheels.