Patent ID: 7059803

Claim:
A powered boatlift comprising: a plurality of support legs; a boat lifting structure moveably mounted to said plurality of support legs; a cable assembly having a connecting end and a lifting end connected in cooperation with said boat lifting structure for causing said boat lifting structure to be raised or lowered; an electric drive unit having a drive shaft capable of rotating in a first direction in response to a first input signal or rotating in a second direction in response to a second input signal; a drive coupling structure coupled to said drive shaft; a ball screw assembly having a first portion coupled to said coupling structure and a second portion coupled to said connecting end; wherein said first portion of said ball screw assembly includes an elongated ball screw having a driving end coupled to said coupling structure wherein said coupling structure rotatably supports said driving end; and said second portion of said ball screw assembly includes a ball nut associated with said elongated ball screw, said ball screw having a cable connection coupled to said connecting end of said cable assembly; and wherein said drive coupling structure includes: a drive train assembly having an input drive coupled to said drive shaft for receiving high-speed low-torque input from said electric drive unit; a torque conversion mechanism coupled to said input drive for converting said high-speed low-torque input to a low-speed high-torque output at an output drive; and an output coupling intermediate said output drive of said torque conversion mechanism and said driving end of said elongated ball screw.