| 摘要 |
A printing mechanism includes a right-angle drive for imparting rotation to a rotary printing element having printing type thereon, rotation of the print element selecting a specific character to be imprinted on a printing medium. The right-angle drive permits the printing element to be moved transversely of the printing medium while receiving rotational mechanical signals for imparting the requisite rotation to the printing element. A shaft having a longitudinal keyway therein passes though a bevel gear of the right-angle drive, there being a key extending from the gear to the keyway to permit the sliding of the gear along the shaft while being controlled in rotation thereabout. A carriage carrying the rotary print element and the right-angle drive is driven in the transverse direction by a worm gear having a worm surface provided with inclined sides which mate with a pair of angled inclined rollers supported by the carriage for engagement with the worm gear. The inclined rollers, the keyway, and a spring forcing together gears of the right-angle drive inhibit any backlash to permit an accurate printing of a message. The foregoing mechanical configuration avoids undue complexity so as to permit rapid operation of the printing mechanism.
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