Motorized lifting system for semi-trailer

Abstract

A motorized lifting system for use on a semi-trailer. The lifting system may comprise a lifting unit capable of mounting to a jack on the semi-trailer, allowing the lifting unit to raise and lower the dolly legs of the jack. The lifting unit may comprise a motor and a series of sprockets and chains connecting the motor to a drive shaft that mounts to a rod of the jack, such that turning the rod raises or lowers the dolly legs.

What is claimed is: 
     
         1 . A lifting system comprising a lifting unit capable of mounting to a jack, the lifting unit comprising:
 a motor;   a worm drive gear assembly powered by the motor; and   a coupling capable of connecting the worm drive gear assembly to a shaft of the jack.   
     
     
         2 . The lifting system of  claim 1  where the coupling comprises:
 a first half of the coupling extending from the worm drive gear assembly, where the first half of the coupling has a plurality of lateral projections extending therefrom; 
 a second half of the coupling, where the second half of the coupling has a plurality of lateral projections extending therefrom and where the lateral projections of the second half of the coupling are capable of interlocking with the lateral projections of the first half of the coupling such that turning the first half of the coupling causes the second half of the coupling to turn; and 
 a clamp capable of clamping the second half of the coupling to the shaft, where the clamp comprises a first portion extending from the second half of the coupling, where the first portion is located on a first side of the shaft during use, and a second portion capable of being placed on a second side of the shaft during use such that the first portion and the second portion are capable of being joined together to clamp the shaft in place relative to the second half of the coupling. 
 
     
     
         3 . The lifting system of  claim 1  further comprising a housing, where the housing has a first compartment housing switch components and a second compartment housing the worm drive gear assembly. 
     
     
         4 . The lifting system of  claim 1  further comprising a plurality of bearings sealing the housing. 
     
     
         5 . The lifting system of  claim 1  further comprising a bracket capable of clamping to a dolly leg of the jack and to the lifting unit. 
     
     
         6 . A lifting system comprising a lifting unit capable of mounting to a jack, the lifting unit comprising:
 a motor;   a power drive shaft connected to the motor, with a power drive sprocket mounted thereon;   an idler shaft with a first idler sprocket and a second idler sprocket mounted thereon;   a drive shaft with a first drive sprocket, a second drive sprocket, and a third drive sprocket mounted thereon, where the drive shaft is capable of receiving a rod of the jack such that turning the drive shaft raises or lowers one or more dolly legs of the jack;   a first chain connecting the first idler sprocket to the first drive sprocket;   a second chain connecting the power drive sprocket to the second drive sprocket; and   a third chain connecting the second idler sprocket to the third drive sprocket.   
     
     
         7 . The lifting system of  claim 6  where the lifting unit further comprises:
 a front cover; and 
 a back cover capable of connecting to the back cover. 
 
     
     
         8 . The lifting system of  claim 6  where the lifting unit further comprises two sealed roller bearings, one on each end of the drive shaft. 
     
     
         9 . The lifting system of  claim 6  where the lifting unit further comprises a pressed in bronze oil impregnated bearing between the first idler sprocket and the second idler sprocket. 
     
     
         10 . The lifting system of  claim 6  where the lifting unit further comprises a pressed in bronze oil impregnated bearing between the first drive sprocket and the second drive sprocket. 
     
     
         11 . The lifting system of  claim 6  where the third drive sprocket is permanently attached to the drive shaft. 
     
     
         12 . The lifting system of  claim 6  where:
 the first idler sprocket has 11 teeth; 
 the second idler sprocket has 11 teeth; 
 the first drive sprocket has 19 teeth; 
 the second drive sprocket has 70 teeth; 
 the third drive sprocket has 70 teeth; and 
 the power drive sprocket has 12 teeth. 
 
     
     
         13 . The lifting system of  claim 6  further comprising one or more of the following:
 wiring cables; 
 a limit switch; 
 a hi-lo knob; 
 a solenoid box; 
 a connecting clamp; and 
 a bolt with a lock nut. 
 
     
     
         14 . The lifting system of  claim 6  further comprising a connecting clamp, where the connecting clamp comprises:
 a first end capable of clamping to one of the dolly legs of the jack; and 
 a second end capable of clamping to the motor. 
 
     
     
         15 . The lifting system of  claim 14  where the first end is U-shaped and the second end is round.