New or improved letter spacing mechanism for typewriting machines

摘要

221,402. Tugwood, R. J., (Daimler- Motoren-Ges.). Dec. 22, 1923. Letter-spacing mechanism.- In letter-spacing mechanism for typewriters of the kind in which the movement takes place during the operation of the type-lever through two ratchet wheels co-operating with a common pawl, the abutting faces of the teeth of the two wheels slope in opposite directions and the tip of the pawl is correspondingly sloped so that the pawl slides noiselessly along the ratchet teeth from one tooth to another. One wheel i. Fig. 1, is fixed to a shaft c carrying a pinion d gearing with the spring driven rack e, and the other wheel h is rotatably mounted on the shaft c and is connected to the wheel i by a spring m, the relative rotation of the ratchets h, i being limited by co-operating abutments h1, i1. The pawl n is pivoted to a spring-pressed lever o carrying an adjustment screw s and operated by an escapement bridge through a rod q, the part being urged towards the ratchet teeth by a spring-pressed pin n2, and its stroke being limited by a stop. The teeth of the wheels h, i and the pawl n are shaped as shown in Figs. 3 and 6. During the movement of a type-lever towards the platen, the pawl n moves to the right from the position shown in Fig. 3, slides over the inclined face of the tooth x of the wheel i, and finally leaves the tooth x and engages a tooth y of the wheel h, the wheel i moving forward to the position shown in Fig. 6. During the return movement of the type-lever, the pawl n slides to the left over the inclined face of the tooth y and into engagement with the tooth x1 of the wheel i, the wheels h, i moving forward into their original relative position, and both having advanced through the distance between the two adjacent teeth x, x1.