GB1341136A - Keyboard printing machine - Google Patents

Abstract

1341136 Selective printing BURROUGHS CORP 18 Oct 1971 [30 Oct 1970] 48315/71 Heading B6F A printer comprises keys 189, Fig. 4, in banks for setting respective print wheels 265, Fig. 5, and a platen 325 for impacting against the print wheels. Depression of a key 189 brings a lower end of a key stem 181 thereof into stopping relation with an arm 251, Fig. 5, on a gear 247 coupled to the print wheel 265. The arm 251 is oscillated during a machine cycle by oscillation of a bail 279 permitting counterclockwise rotation of a gear 259 under bias of a spring 267 and later returning the gear clockwise. The platen 325 is driven for impression by toggle linkages 315, 317 and 319, 321. Interlocks; locking devices.-A spring biased bar 199 serves as a detenting interlock for each key bank, and may be locked to prevent cancellation of a key depression by a key stem 241 formed with a projection 243 capable of preventing movement of bar 199, and a notch 245 for engaging the machine cover to hold the key in depressed position. The key banks set up for character printing are normally cancelled after a printing operation by a flexible clearing member 217 which engages fingers 215 on the bars 199; however this can be prevented by depression of a repeat key (29, Fig. 1, not shown) whereby a bail 231, Fig. 4, is pivoted to block movement of the fingers 215. In the absence of a document to be printed on, depression of the motor bar (33, Figs. 1, 2, not shown) is blocked by a projection (389, Fig. 14, not shown) on a document detector lever (381). Paper shields; hammer constructions.-The platen 325, Fig. 10, is formed with a resilient surface 397 for impacting the print wheels 265, Fig. 5, and steel faces 344 for engaging the surfaces of print wheel support members 301, 303 to limit the depth of impression. Screws 343 are provided to adjust the platen 325. Aligning for impression.-During a machine cycle, the print wheels are aligned and locked in selected position in two stages. A cam 283, Fig. 5, rotating with bail 279, engages an aligning member (287, Figs. 6 to 8, not shown), firstly engaging a rod (291, Figs. 6, 8) with gear teeth on an idler gear 263, Fig. 5, and secondly engaging a plate (297, Fig. 7) between type characters on the print wheels 265.