A driving arrangement for translating a partial angular rotary movement into a full cycle of movement

摘要

950,249. Converting oscillating into rotary motion; ratchet gearing. NATIONAL CASH REGISTER CO. July 17, 1962, No. 27356/62. Heading F2Q. Oscillatory movement of a handle 3 of a cash register or adding machine is converted into unidirectional rotation of a shaft 30 by means of pawls 16, 17 carried by plates 12, 13 fast with the handle 3 and alternately engaging recesses 19, 21 in ratchet wheels 20, 22 to drive the latter alternately in opposite directions, which wheels 20, 22 are respectively geared through an idler 25 and directly to the shaft 30. The handle 3 and a plate 9 fast therewith are biased by a spring 11 into one extreme position determined by a surface 34 on the plate 9 engaging a stop 33. In this position a spring 27 urges the pawl 16 into a recess 19 in the ratchet wheel 20 so that on anticlockwise, Fig. 1, rotation of the handle 9 against the action of the spring 11 the wheel 20 is rotated anticlockwise and drives through the idler 25 the shaft 30 anticlockwise. The anticlockwise rotation of the handle 3 and wheel 20 is limited to 90 degrees by a surface 35 of the plate 9 engaging the stop 33. In this position the spring 27 urges the pawl 17 into a recess 21 on the ratchet wheel 22 which is rotated clockwise when the handle 3 is released and returned to its original position by the spring 11. The clockwise rotation of the wheel 22 drives the shaft 30 in an anticlockwise direction. The sizes of the gears between the wheels 20, 22 and the shaft 30 are chosen so that for each 90 degree rotation of the wheel 20 or 22 the shaft 30 is rotated through 180 degrees. Diametrically opposite recesses 19, 21 in the wheels 20, 22 ensure that when one pawl is in engagement with one of its associated recesses the other pawl is only adjacent one of its associated recesses when the handle 3 is in one of its extreme positions. In Fig. 3 (not shown) a centrifugal governor driven from the shaft 30 prevents overspeeding of the latter. The Specification also states that a dashpot may prevent overspeeding of the shaft 30.