Patent ID: 9624076
Date: 2017-04-18
CPC Classifications: B66D

Claim:
1. A system comprising: a plurality of lifting devices, each lifting device comprising a drum to draw in or let out a line, the drum comprising a groove formed in an outer surface thereof to accommodate the line, a width of the groove being smaller than a diameter of the line and a depth of the groove being deeper than a radius of the line allowing sides of the groove to reach around and grip sides of the line; a motor and transmission located in the drum and coupled to the drum to apply a torque thereto; a guide extending into the groove immediately over the line in order to push the line into the groove; a grouping module to group the plurality of lifting devices for synchronized operation in lifting a shared load; and a synchronization module to monitor operating parameters of the plurality of lifting devices in the group and, based on the operating parameters, adjust the operating parameters of at least one lifting device in the group to maintain synchronization between the motorized lifting devices.