| 摘要 |
A hydraulic transmission is disclosed through which the fountain and ductor roll assemblies of an offset printing press are variably driven from a reciprocable drive mechanism having a constant stroke. The transmission allows for infinite variation in the angular motion of the respective rolls, and includes a pair of hydraulic cylinders which are connected in a closed hydraulic circuit, so that one piston of the cylinders is displaced by the drive mechanism, whereas the other piston is displaced by means which alternately yield to the counterstroke of the aforesaid other piston during the displacement of the one piston. By adjusting the volumetric capacity of the circuit, within a selected maximum pressure, the counterstroke of the aforesaid other piston is varied until it produces the angular motion desired for the rolls.
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