| 摘要 |
1293538 Ink-ribbon mechanisms E V BYERS 16 Dec 1969 [20 Dec 1968] 60540/68 Heading B6F Automatic ribbon reversing.-The drive from a carriage movement rotating a shaft 10 is transmitted alternatively to ribbon spool ratchet wheels 17, 18 by pawl carrying bars 25, 26 in accordance with the position of a lug 44 engaging alternative lands 48 of a disc 47. This effects coupling of the bars 35, 36 alternately to the ratchet wheels 17, 18. The bars 25, 26 each have two pawls 27 or 29 which are biased towards the ratchet wheels 18, 17. Alternatively one bar is disconnected from its ratchet by the bifurcated ends of bars 35, 36. These operate, one to disconnect the ratchet and pawls and the other to connect them when tension in the ribbon does not allow a multilobe cam 19 to oscillate the pawl arms, but instead rotate the lug 43 and move the bars 35, 36. |
