Abstract: A motorized gearbox having a drive shaft is provided. The motorized gearbox provides input power to rotate the drive shaft. The drive shaft is inserted into a jack housing. Rotation of the drive shaft raises or lowers the jack housing. The integrated drive shaft is capable of replacing a hand crank and an input shaft of a mechanically operated jack to convert the mechanically operated jack to a motorized jack.

Abstract: In an embodiment of the present invention a retention assembly for a jack includes a housing, a bushing, a shaft, a gear, a pin, and a spring. The housing includes a housing aperture, into which the bushing is positioned. The shaft, which includes a shaft aperture, extends through the bushing such that the portion of the shaft defining the shaft aperture is positioned within the housing. The gear, which includes a gear aperture, is positioned on the shaft such that the gear and shaft apertures align to accommodate the pin. The spring is positioned on the shaft and within the housing such that a first end of the spring applies a force to the bushing to retain the bushing in the housing aperture and a second end of the spring engages the pin to retain the pin within the shaft and gear apertures.

Abstract: A mechanical jack that is used with trailers that has a functional combination of several working gears as well as a drop leg feature is disclosed. The mechanical jack has a gearbox having gears that not only have the capacity to handle a relatively heavy load, but also have the ability to handle small and midsize loads while maintaining sufficient and commercially acceptable cranking speeds without excessive force required. The jack includes a crank or handle for use with the mechanical jack that assists in both effective raising and lowering of the jack, as well as efficient transition from one working gear to another. The jack may also utilize an electric motor as the source of input power to the jack.