Patent ID: 7631730

Claim:
A powered controlled acceleration suspension work platform hoist system ( 10 ) for raising and lowering a work platform ( 100 ), having a sinistral end ( 110 ) and a dextral end ( 120 ), on a sinistral rope ( 400 ) and a dextral rope ( 500 ) at a predetermined acceleration, comprising: a sinistral hoist ( 200 ) having a sinistral motor ( 210 ), a sinistral traction mechanism ( 220 ) designed to cooperate with the sinistral rope ( 400 ), and a sinistral gearbox ( 230 ) for transferring power from the sinistral motor ( 210 ) to the sinistral traction mechanism ( 220 ), wherein the sinistral hoist ( 220 ) is releasably attached to the work platform ( 100 ) near the sinistral end ( 110 ); a dextral hoist ( 300 ) having a dextral motor ( 310 ), a dextral traction mechanism ( 320 ) designed to cooperate with the dextral rope ( 300 ), and a dextral gearbox ( 330 ) for transferring power from the dextral motor ( 310 ) to the dextral traction mechanism ( 320 ), wherein the dextral hoist ( 320 ) is releasably attached to the work platform ( 100 ) near the dextral end ( 120 ); a variable acceleration motor control system ( 600 ) releasably attached to the work platform ( 100 ) and in electrical communication with a constant frequency input power source and the sinistral motor ( 210 ) and the dextral motor ( 310 ) wherein the variable acceleration motor control system ( 600 ) controls the rate at which the sinistral motor ( 210 ) accelerates the sinistral traction mechanism ( 220 ) and the rate at which the dextral motor ( 310 ) accelerates the dextral traction mechanism ( 320 ) thereby controlling the acceleration of the work platform ( 100 ) as the work platform ( 100 ) is raised and lowered on the sinistral rope ( 400 ) and the dextral rope ( 500 ); and a platform control system ( 700 ) releasably attached to the work platform ( 100 ) and in electrical communication with the variable acceleration motor control system ( 600 ), the sinistral motor ( 210 ), and the dextral motor ( 300 ), having a user input device ( 710 ) designed to accept instructions to raise or lower the work platform ( 100 ).