Multiple-speed transmission of countershaft construction which can be shifted under load

Claim 1

A multiple speed transmission, comprising: (A) a first and a second shift unit, each said shift unit comprising, respectively: (1) a rotatable shaft, the rotatable shaft of said first shift unit being parallel to the rotatable shaft of said second shift unit; (2) a first gear fixed for rotation with said shaft; (3) a second gear on said shaft and rotatable with respect thereto; (4) a third gear on said shaft and rotatable with respect thereto; said third gear having a different pitch diameter than said second gear, said second and third gears being located on opposite sides of said first gear, the diameter of said first gear being greater than the diameter of at least one of said second and third gears; (5) clutch means for selectively coupling one of said second and said third gears to rotate together with said first gear, said clutch means including first and second disk clutches arranged on either side of said first gear, said first disk clutch being adapted to selectively couple said first gear to said second gear, said second disk clutch being adapted to selectively couple said first gear to said third gear; (6) a fourth gear fixed for rotation with said shaft, said fourth gear being further away, as measured along the axis of said shaft, from said first gear than at least one of said second and third gears; (B) said gears of both said shift units being, at least indirectly, in engagement such that said first gear of each said unit is in engagement with and defines a set of gears with said second gear of the other said unit, and said third gear of each said unit is in engagement with and defines a set of gears with said fourth gear of the other said unit, whereby four engaging sets of gears are formed; and (C) a reverse transmission connected to said first shift unit for reversing the direction of rotation of said shaft of said first shift unit, said reversing transmission comprising a third shift unit, said third shift unit including: (1) a second shaft; a fifth gear fixed to said second shaft for rotation therewith; said fifth gear engaging said first gear of said first shift unit for rotation therewith; (2) a sixth gear and a seventh gear located on and being rotatable with respect to said second shaft; (3) second clutch means for selectively coupling one of said sixth and seventh gears to rotate with said fifth gear; (4) first means for rotating said sixth gear, and thereby for rotating said fifth gear, in one direction when said second clutch means has coupled said fifth and said sixth gears; and (5) second means for rotating said seventh gear, and thereby for rotating said fifth gear, in a second, opposite direction when said second clutch means has coupled said fifth and said seventh gear.