Mechanical transmission and control method therefor

A combined range and splitter type compound change gear transmission comprising a main transmission section connected in series with an auxiliary transmission section, said auxiliary transmission section comprising a housing, an auxiliary section input shaft extending into said housing and driven by said main transmission section and an output shaft extending from said housing, said main transmission section comprising a plurality of main transmission section positive clutches for selectively drivingly engaging selected main section gearing to said auxiliary section input shaft, said auxiliary transmission section comprising:

• a splitter gear, a splitter/range gear and a range gear all generally coaxial with and rotatable relative to said auxiliary section input shaft and said output shaft;
• an auxiliary section countershaft assembly comprising an auxiliary section countershaft rotationally supported in said housing, a first auxiliary countershaft gear rotatably fixed to said auxiliary countershaft and constantly meshed with said splitter gear, a second auxiliary countershaft gear rotationally fixed to said auxiliary countershaft and constantly meshed with said splitter/range gear and a third auxiliary countershaft gear rotationally fixed to said auxiliary countershaft and constantly meshed with said range gear;
• a splitter clutch assembly fixed for rotation with said auxiliary section input shaft and having a first position for coupling said splitter gear to said auxiliary section input shaft and a second position for coupling said splitter/range gear to said auxiliary section input shaft;
• a two-position synchronized range clutch assembly fixed for rotation with said output shaft and having a first position for coupling said splitter/range gear to said output shaft and a second position for coupling said range gear to said output shaft;
• and,
• control means independently positioning each of aid splitter clutch assembly and range clutch assembly in a selected one of the two positions thereof, said transmission characterized by;
• said control means allowing positioning and maintaining of said splitter clutch in a third position thereof for drivingly disconnecting said splitter gear and said splitter/range gear from said auxiliary section input shaft and further including means for sensing disengagement of all of said main section gearing from said auxiliary section input shaft and for automatically positioning said splitter clutch in the third position thereof in response thereto.

A method for controlling change gear transmissions of the type comprising:

• an input component comprising an input shaft, an input gear rotationally fixed to said input shaft, at least one countershaft carrying a plurality of countershaft gears thereon, one of said countershaft gears constantly meshed with said input gear and a plurality of mainshaft gears constantly meshed with other of said countershaft gears;
• a connecting component comprising a mainshaft and a plurality of first and second positive mainshaft clutch members rotationally fixed to said mainshaft, said connecting component independently rotatable of said input component;
• and
• an output component comprising an output shaft, said output component independently rotatable of said connecting component,
• said input gear and mainshaft gears selectively clutchable one at a time to said mainshaft by first clutch means including said first clutch members,
• said output shaft selectively drivingly engaged and disengaged to said mainshaft by second clutch means including said second clutch member;
• and
• manually operated control means for selectively positioning said first clutch means in the engaged and disengaged positions thereof;
• said method characterized by:
• sensing positioning of all of said first clutch means in the disengaged positions thereof,
• providing a signal indicative of all of said first clutch means in the disengaged positions thereof,
• responding to said signal by automatically causing said second clutch means to assume the disengaged position thereof to drivingly disengage said output shaft from said mainshaft.