Milling machine

A self-propelled work machine, comprising:

• a machine frame supportable by a plurality of ground engaging units;
• a support device connected between said machine frame and at least one of said ground engaging units, said support device including a lifting column having a lifting column axis and being adapted to controllably raise and lower said associated connected ground engaging unit about said axis relative to said machine frame;
• a first actuator connected to said support device and adapted to move said one ground engaging unit between projecting and retracted positions relative to said machine frame;
• and
• a second actuator connected to said lifting column and adapted to cause at least a portion of said lifting column to rotate about said lifting column axis relative to said machine frame, said second actuator being positioned at a location linearly spaced apart from said first actuator along said lifting column axis.

A method of controlling a pair of actuators connected to a controller, at least one of said actuators being a rotary actuator, to selectively position one of a plurality of ground engaging units connected to a respective lifting column having a lifting column axis and supporting a frame of a self-propelled work machine, comprising the steps of:

• raising said one ground engaging unit with said lifting column until said one ground engaging unit is free from engagement with the ground;
• actuating a first one of said actuator pair to move said one ground engaging unit from one to the other of said projecting and retracted positions relative to said machine frame;
• actuating a second one of said actuator pair to rotate said one ground engaging unit about said lifting column axis in a manner coordinated with the actuation of said first actuator to maintain the same rotational direction of said ground engaging unit in each of said projecting and retracted positions;
• and
• lowering said one ground engaging unit with said lifting column until said one ground engaging unit is again in frame supporting engagement with the ground.

A self-propelled work machine, comprising:

• a machine frame supportable by a plurality of ground engaging units;
• support means for supporting said machine frame, said support means being connected to said machine frame and including a generally vertically oriented lifting column having a lifting column axis and being connected to at least one of said ground engaging units;
• first actuatable means for moving said one ground engaging unit between projecting and retracted positions relative to said machine frame;
• second actuatable means for rotating said one ground engaging unit to maintain the same rotational direction of said ground engaging unit in each of said projecting and retracted positions, said second actuatable means being positioned at a location spaced apart from said first actuatable means along an axis of said lifting column;
• and
• controller means for coordinating the actuation of said first and second actuatable means.