Abstract: A gear drive with variable gear ratio employs a set of idler gear shafts eccentrically mounted on rotating disks surrounding input and output drive shafts. Simple rotation of the disks engages and disengages, in sequence, different idler gear assemblies as mounted on the disks, with and from both the input and output drive shafts providing a simple changing of gear ratio and eliminating unnecessary turning of idler shafts not used for the direct transmission of power.

Abstract: A gear reducer kit has one shaft mounted in a rotatable quill which rotates along an axis offset from the shaft axis. The quill may be fixed with respect to the gear reducer at one of several discrete index position, each associated with a different input pinion gear corresponding to the distance between the shaft and an idler gear. A flange rim guides the rotation of the quill mode with respect to the housing. The idler gear is opposed to the mounting base of the gear reducer with respect to the shaft to permit spacing plates to be added to adjust the mounting spacing.