| 摘要 |
A first carriage, which is arranged to vertically reciprocate within a first housing, is provided with two air clutches and a continuously moving chain. The chain is arranged to move over co-planar spaced sprockets so as to present one direction of chain motion to the left side of the carriage and a second direction of chain motion to the right side of the carriage. The carriage is also provided with two chain engaging sprockets each controlled by a respective one of two air clutches. The chain engaging sprockets on the carriage normally idle with chain motion. However, actuation of one of the controlling air clutches halts the spinning of its associated sprocket and forces the sprocket and clutch to act as a unit to thereby move the carriage upwardly or downwardly along the length of the chain in a direction dependent upon which portion of the continuously moving chain was so engaged. Means are provided to automatically reverse the stroke, to vary the length of the stroke and to vary the speed of the stroke. A second carriage, which is arranged to vertically reciprocate in a second housing adjacent to the first housing, is provided with a chain engagement means. A suitably arranged second chain interconnects the first and second carriages. Reciprocation of the first carriage causes reciprocation of the second carriage. The chain engagement means permits securement of the second carriage to any selected portion of the second chain. This adjustable connection permits an operator to select a variety of stroke patterns for the second carriage.
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