Clamshell cranes are hoisting machines (machines with cyclic action) designed for handling bulk materials. The name of these cranes comes from the load gripping device – clamshell grab. In addition to the clamshell (two-jaw) grab for bulk materials, there are grabs designed for long-size and single loads. In the case of high-productivity bulk materials handling, double-rope clamshells are most suitable, which require a specialized clamshell crane with two hoisting mechanisms. The article discusses a reducer for a crane hoisting mechanism with an embedded planetary gear train (PGT), allowing the two ropes to move together, at the same speed, as well as independently of each other, or together at different speeds. The different modes of operation of the mechanism are considered. An analysis of the possible kinematic schemes of the PGT is made. The necessary kinematic calculations are made to select the most suitable variant of the PGT.
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