Change gear planetary transmission

An improved change speed planetary transmission of the type comprising a housing (18), a first shaft (12) and a second shaft (14) independently rotatable about a common axis (16) in the housing and planetary gearing (102) drivingly connecting said first shaft to said second shaft, said planetary gearing comprising a sun gear (104) axially and rotationally fixed with said first shaft, a plurality of planet gears (110) constantly meshed with said sun gear and rotatable on planet gear shafts (114) carried by a planet carrier (116) axially and rotationally fixed with said second shaft, and a ring gear (120) constantly meshed with said planet gears, said ring gear selectively rotationally fixed by a first positive clutch connection to a member (18) independently rotatable relative to said first and second shafts to provide a first drive ratio between said first and second shaft and selectively rotationally fixed by a second positive clutch connection (122, 128, 126) to said sun gear and said first shaft to provide a direct drive ratio between said first and second shaft, said ring gear axially moveable in said housing relative to said sun gear and said planet carrier to a first position whereat said ring gear is fixed by said first positive clutch connection for rotation with said member and to a second position whereat said ring gear is fixed by said second positive clutch connection for rotation with said sun gear and first shaft and means (136) engageable by a shifting member (146) fixed for axial movement with said ring gear for selectively axially moving said ring gear to said first and second axial positions thereof, the improvements characterized by:

• said second positive clutch connection including a positive clutch member (126) rotationally and axially fixed to said first shaft and carrying external clutch teeth (128) thereon for positive engagement with internal clutch teeth (122) rotationally fixed to said ring gear, said external clutch teeth (128) carried by said clutch member define a pitch radius (R.sub.R) relative to the axis of rotation of said input shaft equal to the pitch radius defined by the internal clutch teeth of said ring gear for direct engagement therewith when said ring gear is in the second axial position thereof, and further comprising synchronizing means (152 and 156) for synchronizing the rotational speed of said ring gear to the rotational speed of said member and said input shaft, respectively, prior to permitting said ring gear to be moved to said first and second, respectively, axial positions thereof, the synchronizing means (156, 158) for synchronizing said ring gear and sun gear prior to movement of said ring gear to the second axial position thereof comprising a conical surface (158) fixed for rotation with said second shaft.