| 摘要 |
A pair of rakes, each provided with a plurality of tines projecting in a substantially horizontal direction. The rakes are mounted for movement in a substantially triangular path between an advanced position and a retracted position spaced from one another in the direction of elongation of the tines, and also between an upper and a lower level while they are in the advanced position. Movement of the rakes is controlled so as to assure that whenever one of the rakes is in the advanced position and at the upper level another rake will move to the advanced position and to the lower level before the first-mentioned rake moves away towards the retracted position.
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