PR-750B PAVEMENT PROFILER
The PR-750B Roto-Mill is a pavement mining machine mounted on three crawler tracks that provide a maximum travel speed of 2 miles (3.2 km) per hour or a maximum operating speed of 75 feet (23 m) per minute. The rotating mandrel cutter uses tungsten carbide bits (teeth) to remove pavement to a maximum width of 10-feet-0-inches (3 m) and a maximum depth of 10 inches (25.4 cm). Material loosened by the cutter is channeled onto a lower conveyor that moves the material back under the machine and onto an upper conveyor that moves the material up to a maximum discharge height of 14 feet (4.3 m). Dust created by the cutting operation is suppressed by a pressurized water fog spray directed into the cutter housing and lower conveyor enclosure.
A AVSpare 3412 diesel engine supplies all the power for the PR-750B. The engine acts through a gearbox to drive three tandem hydraulic pumps that supply oil for four separate machine functions. The track drive pump supplies the pressurized hydraulic oil to turn the three track drive motors. The control (auxiliary) pump mounts to the rear of the track drive pump and supplies the oil for machine functions such as steering and elevation control. The other pump drives the three conveyor motors, one motor on the lower conveyor and two motors on the upper conveyor.
NOTE: THE ENGINE CANNOT BE STARTED UNLESS THE TRACK DRIVE PUMP IS IN NEUTRAL.
The track drive pump or control pump may be replaced separately. The conveyor pump, however, must be replaced as a unit - anytime one section is replaced, the other section must also be replaced.
The diesel engine also drives the dust suppression water system pump, an air compressor and a 54-inch (137 cm) fan that provides the flow of cooling air through the hydraulic oil cooler and the engine radiator. Compressed air is used for the air operated cutter clutch and for air operated hand tools.
The cutter has replaceable snap-in cutter bits (teeth) that are mounted in holders welded to the cutter flighting. Easy access to any one or all bits and holders is provided by a hydraulically actuated full-width door and by an auxiliary cutter drive hydraulic system. The auxiliary cutter drive hydraulic system will turn the cutter slowly when the cutter is not in contact with the ground. An air operated hammer supplied with each machine is used to drive the bits out of the holders.
NOTE: THE CUTTER CLUTCH CANNOT BE ENGAGED UNLESS THE CUTTER DOOR IS CLOSED.
Machine steering is performed by a hydraulic system manually controlled by the operator. The hydraulic system that adjusts the elevation of the mainframe and attached cutter can be controlled manually or automatically. Automatic elevation control requires the use of two elevation sensors, one on each side of the machine, or one elevation sensor on either side of the machine and the cross slope sensor.
The cutter assembly is pin-connected to the mainframe so that the cutter can be easily removed when the machine must be transported to a new site. The machine can be shipped as a 10-foot-5-inch (3.2 m) load with the cutter elevation sensors and grade reference assemblies removed. The cutter shipping weight is 18,000 pounds (8182 kg); the shipping weight of the rest of the machine is 63,000 pounds (28 636 kg). With the cutter removed, the shipping height of the machine is 11-foot-5-inches (3.5 m). The shipping length is 56 feet (17 m).