초록 ▼

A power option is provided for a manually-operated material lift that employs a telescoping mast system which is extended or retracted by a winch. In one embodiment a reversible electric motor is connected to the winch via two-way reduction gearing that remains in the drive train during manual opera

A power option is provided for a manually-operated material lift that employs a telescoping mast system which is extended or retracted by a winch. In one embodiment a reversible electric motor is connected to the winch via two-way reduction gearing that remains in the drive train during manual operation and requires no clutches or disconnect means. In a second embodiment a crankshaft that operates the winch is provided with slide couplings that either engage the manual operating handles or release the handles and engage the motorized drive. The power option is initiated by selecting the position of a reversing switch that controls the motor, and closing an on/off switch which energizes the motor for rotation in the selected direction. When the on/off switch is open, the lift may be manually operated in the conventional manner.

대표청구항 ▼

[ Having thus described the invention, what is claimed as new and desired to be secured by letters patent is as follows:] [1.] In a material lift having a telescoping mast assembly including a stationary support section and at least one lifting section carried by the support section and movable betw

[ Having thus described the invention, what is claimed as new and desired to be secured by letters patent is as follows:] [1.] In a material lift having a telescoping mast assembly including a stationary support section and at least one lifting section carried by the support section and movable between a lower, retracted position and an upper, extended position, and where a winch is mounted on the support section for raising and lowering the lifting section, the winch having a crankshaft which can be turned to operate the winch and raise and lower the lifting section, the improvement comprising:a reversible electric motor unit mounted on said support section and having a drive shaft,drive means coupling said drive shaft with a driven member on said crankshaft,a handle on said crankshaft,a selectively operable coupling rotatable with said crankshaft and movable between a first position engaging said handle for joining the handle to the crankshaft for manual operation of the winch, and a second position engaging said driven member for joining the driven member to the crankshaft for motorized operation of the winch, anda control circuit connected to said motor and having on/off switch means for selecting motorized operation or manual operation of the winch, and reversing switch means for selecting upward or downward movement of the lifting section during motorized operation, whereby to provide the option of motorized drive for the lift.