Patent ID: 7357746

Claim:
An eccentric gear box consisting of at least one gear engagement mechanism, at least two eccentric gear pairs with different ratios between number of teeth of its individual gears, at least one input shaft, at least one output shaft and multiple eccentrics; wherein each eccentric gear pair consists of one circular gear, with internal gear teeth, in mesh with another circular gear with external gear teeth; wherein number of external gear teeth is less than the number of internal gear teeth; wherein one of the gears of eccentric gear pair is a revolving gear ad the other gear is a fixed orientation gear; wherein multiple eccentrics are mounted on fixed orientation gear as to keep its orientation fixed while allowing its axis to revolve around the axis of revolving gear; revolving gear is free to revolve around its axis, which is common axis to all eccentric gear pairs; eccentrics associated with same eccentric gear pair have approximately equal eccentricity; individual eccentric revolves around its fixed axis and is free to revolve with respect to the associated fixed orientation gear; wherein one eccentric associated with each fixed orientation gear is mounted on input shaft; wherein revolving gears associated with individual eccentric gear pairs, are connected to output shaft; at least one gear engagement mechanism is employed to select an eccentric gear pair to be effectively engaged between input shaft and output shaft as to revolve input and output shafts with speed ratio that is obtained from selected eccentric gear pair.