Method and apparatus for preselecting gear ratios in a power transmission

A transmission control system for a work vehicle of the type including an engine coupled to a transmission for driving the vehicle in forward and reverse directions, the transmission including a plurality of intermeshing gears and a plurality of clutches associated with the gears, the clutches being selectively engageable in predetermined combinations to obtain predetermined gear ratios between an input shaft and an output shaft of the transmission, the control system comprising:

• an operator-movable command mechanism, the command mechanism generating operator-induced forward gear ratio preselection signals and reverse gear preselection signals independent of each other;
• a memory circuit for storing preselected forward and reverse gear ratio values;
• a display circuit;
• and
• a control circuit coupled to the command mechanism, to the memory circuit and to the display circuit, the control circuit receiving the preselection signals and storing in the memory circuit values representing independent preselected forward and reverse gear ratios established via the preselection signals, the display circuit simultaneously displaying indicia representing the independent preselected forward gear ratio and indicia representing the independent preselected reverse gear ratio.

A transmission control system for a work vehicle of the type including an engine coupled to a transmission for driving the vehicle in forward and reverse directions, the transmission including a plurality of intermeshing gears and a plurality of clutches associated with the gears, the clutches being selectively engageable in predetermined combinations to obtain predetermined gear ratios between an input shaft and an output shaft of the transmission, the control system comprising:

• a command mechanism generating operator-induced command signals representative of desired gear ratios;
• a display circuit including operator-observable indicia, including first indicia representative of a driving direction selected by an operator, second indicia representative of a forward gear ratio selected by the operator via the command mechanism, and third indicia representative of a reverse gear ratio selected by the operator via the command mechanism;
• and
• a control circuit coupled to the command mechanism and to the display circuit, the control circuit generating control signals and applying the control signals to the display circuit for indicating via the indicia the driving direction and the forward and reverse gear ratios commanded by the operator.

A method for preselecting a transmission gear ratio in a work vehicle of the type including an engine coupled to a transmission for driving the vehicle in forward and reverse directions, the transmission including a plurality of intermeshing gears and a plurality of clutches associated with the gears, the clutches being selectively engageable in predetermined combinations to obtain predetermined gear ratios between an input shaft and an output shaft of the transmission, the method including the steps of:

• (a) storing in a memory circuit forward and reverse gear ratio values corresponding to preselected gear ratios for driving the vehicle in the forward and reverse directions, respectively;
• (b) executing an operator-induced forward gear preselection routine to reset the forward gear ratio value to an operator-selected gear ratio wherein the stored reverse gear ratio value is unaffected by said reset;
• and
• (c) storing in the memory circuit the reset forward gear ratio value.

A method for preselecting a transmission gear ratio in a work vehicle of the type including an engine coupled to a transmission for driving the vehicle in forward and reverse directions, the transmission including a plurality of intermeshing gears and a plurality of clutches associated with the gears, the clutches being selectively engageable in predetermined combinations to obtain predetermined gear ratios between an input shaft and an output shaft of the transmission, the method including the steps of:

• (a) storing in a memory circuit forward and reverse gear ratio values corresponding to preselected gear ratios for driving the vehicle in the forward and reverse directions, respectively;
• (b) executing an operator-induced reverse gear preselection routine wherein the reverse gear ratio value is reset to an operator-selected gear ratio wherein the stored forward gear ratio value is unaffected by said reset;
• and
• (c) storing in the memory circuit the reset reverse gear ratio value.