Abstract: A milling machine includes a main frame, a rotatable cutter drum coupled with the frame, and an engine mounted to the frame and operatively connected with the drum, and crawler assemblies connected with the frame and including a hydraulic motor. A pump is disposed on the frame for driving the crawler motor and is adjustable to vary a speed of the motor. A regulator adjusts cutter drum speed, a speed selector generates an input corresponding to a desired drum speed, and a sensor senses a drum speed. A control receives input from the selector and the sensor and operates the regulator such that drum speed corresponds to the desired speed. Further, the control also compares sensed drum speed with desired drum speed and adjusts the pump to reduce crawler motor speed when the sensed drum speed has a value lesser than a predetermined portion of the desired drum speed.

Abstract: A propulsion system is for a road milling machine with a rotatable cutter drum (3). The system includes four crawler assemblies (12) movably coupled with the mainframe so as to define front and rear, and left and right, pairs of crawler assemblies. Four steering actuators (14) are each coupled with a separate crawler assembly and each angularly displaces the crawler about a vertical axis (12a). A first pump (16A) is fluidly coupled with the left pair of crawlers and a second pump (16B) is fluidly coupled with the right pair of crawlers. A control (20) is configured to selectively operate the four actuators in a plurality of different steering modes, one steering mode being a circle steer mode, and to operate the two pumps such that one of the left and right pairs of crawlers are drivable by the first pump in one direction while the other pair of crawlers are drivable in an opposing direction.

Abstract: A propulsion system is for a road milling machine with a rotatable cutter drum (3). The system includes four crawler assemblies (12) movably coupled with the mainframe so as to define front and rear, and left and right, pairs of crawler assemblies. Four steering actuators (14) are each coupled with a separate crawler assembly and each angularly displaces the crawler about a vertical axis (12a). A first pump (16A) is fluidly coupled with the left pair of crawlers and a second pump (16B) is fluidly coupled with the right pair of crawlers. A control (20) is configured to selectively operate the four actuators in a plurality of different steering modes, one steering mode being a circle steer mode, and to operate the two pumps such that one of the left and right pairs of crawlers are drivable by the first pump in one direction while the other pair of crawlers are drivable in an opposing direction.

Abstract: A milling machine includes a main frame, a rotatable cutter drum coupled with the frame, and an engine mounted to the frame and operatively connected with the drum, and crawler assemblies connected with the frame and including a hydraulic motor. A pump is disposed on the frame for driving the crawler motor and is adjustable to vary a speed of the motor. A regulator adjusts cutter drum speed, a speed selector generates an input corresponding to a desired drum speed, and a sensor senses a drum speed. A control receives input from the selector and the sensor and operates the regulator such that drum speed corresponds to the desired speed. Further, the control also compares sensed drum speed with desired drum speed and adjusts the pump to reduce crawler motor speed when the sensed drum speed has a value lesser than a predetermined portion of the desired drum speed.