Speed reducing device

Claim 1

A speed reducing device, comprising: an input shaft; an output transmitting member journaled in axial alignment with said input shaft; an eccentric and a counterweight carried by the input shaft, the center of gravity of the counterweight lying on a line which extends from the input shaft diametrically opposite to a line from the input shaft to the center of gravity of the eccentric; a primary and a secondary gear mounted upon the eccentric for rotation together about said input shaft, said primary gear having a different number of teeth than said secondary gear, the primary and secondary gears being axially spaced along the input shaft to form a cavity and the counterweight being disposed within the cavity between said primary and secondary gears; a fixed gear spline in engagement with said primary gear, the primary gear having a smaller number of teeth than the fixed gear spline; said output transmitting member including a rotatable output gear spline in engagement with said secondary gear, the secondary gear having a smaller number of teeth than the output gear spline; a casing secured to said fixed gear spline; a bearing assembly mounted between said casing and said rotatable output gear spline in a direct straight line with the lines of force transferred by the gear teeth which are in mesh, said output gear spline being in direct engagement with said fixed gear spline through said casing and said bearing assembly, said casing and bearing assembly being located radially outwardly from said secondary gear to thereby achieve a short, compact, stiff torque path which extends from the fixed gear spline through the periphery of the primary and secondary gears to the output gear spline.