Electrically controlled pressurized fluid actuated X-Y shifting mechanism

An X-Y shifting mechanism (30) for controlling the shifting of mechanical change gear transmission of the type comprising a shift bar housing assembly (10) having three substantially parallel shift rails (12, 14, 16) axially movable in a first axial direction (Y--Y) in a shift bar housing, each of said rails having a shift fork (18, 20, 22) associated therewith and a block mechanism (24, 26, 28) engagable by the inner end of a manually operated shift lever movable in a second direction (X--X) substantially perpendicular to said first direction to be aligned with a selected one of said block mechanisms and in said first direction to move the selected one of said shift rails from a first axially nondisplaced position to a second position axially displaced in one direction along said first axis (Y--Y) or to a second position axially displaced in the opposite direction along said first axis;

• said X-Y shifting mechanism (30) characterized by:
• a shift mechanism housing (32), mountable to said shift bar housing at the opening thereof provided for said shift lever, a shift finger (38) extending from said X-Y shift mechanism housing (32) for extension through said opening and cooperation with said block mechanism;
• a first shaft (68) axially movable in said first axial direction (Y--Y) in said shift mechanism housing, said shift finger (38) fixed to first shaft (68) for axial movement therewith, said shift finger pivotably movable about the axis of (142) said first shaft;
• a second shaft (110) axially movable in said second axial direction (X--X) in said shift mechanism housing, said second shaft having means (132) axially movable therewith engaging said shift finger at a point (140) offset the axis (142) of said first shaft to a first position aligned with a first shift rail block mechanism, a second position aligned with a second shift rail block mechanism and a third position aligned with a third shift rail block mechanism;
• a first electrically controlled pressurized fluid actuated control (46) for selectively positioning said first shaft in any selected one of three different selectable axial positions along said first axial direction, said first control comprising a first piston and cylinder assembly defining three (86, 88, 94) selectively pressurized first chambers and three electrically controlled first valves (150, 152, 154) for selectively independently pressurizing and exhausting said first chambers.
• a second electrically controlled pressurized fluid actuated control (42) for selectively positioning said second shaft in any selected one of three different selectable axial positions along said second axial direction, said second control comprising a second piston and cylinder assembly defining three selectively pressurized and exhausted second chambers (116, 118, 122) and three electrically controlled second valves (156, 158, 160) for selectively independently pressurizing and exhausting said second chambers.