1. Mainframe Assembly
2. Leg Assemblies
3. Steering Assembly
4. Track Assemblies
5. Powerpack Assembly
6. Cutter Assembly
7. Conveyor Assembly (Base Reclaimer)
8. Water Tank
9. Hydraulic Oil Tanks
10. Fuel Tank
11. Control Console
12. Elevation Sensors
13. Cross Slope Sensor (Optional)
14. Right or Left Leg Slope Control (Optional)
The mainframe is an all welded, heavy plate assembly with box type structural support beams. Decking is grid plate with grated inspection panels. The mainframe rides on three hydraulic cylinders which fit inside the legs and are used to adjust the elevation of the mainframe.
The leg assemblies each consist of a leg barrel, a leg yoke and an elevation cylinder. The leg yoke fits inside the leg barrel which is an integral part of the mainframe. The elevation cylinder fits inside the yoke and connects to the leg barrel and yoke. Each track assembly includes a pivot which connects the track to the leg yoke and allows the track to pivot up and down.
WHEN MOVING A PR-450 UP ONTO OR DOWN OFF A CURB OR OTHER OBSTRUCTION, USE CRIBBING TO FORM A RAMP FROM THE LOWER LEVEL TO THE UPPER LEVEL OR THE MACHINE LEGS MAY BE DAMAGED.
Steering is accomplished by the steering cylinder acting through the steering plate on the front yoke to rotate the yoke within the leg barrel. When the yoke rotates, the front track turns. Each rear leg is connected to the mainframe by an adjusting plate and rod that allow a small adjustment of the track position. The rear legs and tracks do not turn.
The steering assembly consists of a hydraulic cylinder which is pin-connected to the steering plate and mainframe. When the steering control lever is moved to "Left", hydraulic oil from the auxiliary pump enters the rod end of the steering cylinder, causing the cylinder to retract and turn the front track to the left. When the steering control lever is moved to "Right", the oil enters the head end of the steering cylinder to turn the track to the right.
The track assemblies consist of a frame, a hydraulic motor, a planetary gear reducer (TORQUE-HUB), a drive sprocket, five rollers, and an idler assembly which includes the idler roller, a yoke and a tensioner. A pivot pin fits through a cylinder in the track frame to attach the track assembly to the leg yoke and provide a pivot point for the track assembly. The front track assembly also has a hydraulic disc brake. Optional rubber track pads are available to provide extra traction on concrete surfaces.
NOTE: THE TORQUE-HUBS CAN BE DISENGAGED SO THAT THE MACHINE CAN BE TOWED SHORT DISTANCES WITHOUT DISCONNECTING HYDRAULIC LINES. SEE PAGE 4-31.
The hydraulic motor has a splined output shaft that fits into the gear reducer to drive the gear reducer and the sprocket bolted to the gear reducer. The sprocket teeth engage the track chain bushings to pull the machine forward over the portion of the track that is on the ground.
The track chain rides over the upper track frame and around the front roller (idler) to the ground. The lower rollers (track rollers) ride on the track and distribute the machine weight evenly over the track.
The tension in the track chain is controlled by the tensioner which consists of a spring, a cylinder and a piston. The pressure in the cylinder acts against the piston to compress the spring which pushes the yoke and idler forward against the track chain. The greater the pressure in the cylinder, the more the spring is compressed and the greater the force transmitted to the track chain. The pressure in the cylinder can be reduced by loosening the fitting on the cylinder. The pressure can be increased by using a high pressure grease gun connected to the fitting. The spring acts as a shock absorber to prevent damage to the track when a foreign object, such as a rock, passes between the track chain and a roller or sprocket.
The hydraulic disc brake mounted in the front track assembly is intended for use as a parking brake or emergency brake only, since the primary braking is provided by the track drive hydrostatic transmission. The brake will be engaged whenever:
- 1. The auxiliary hydraulic pressure falls below 180 psi.
- 2. The emergency and parking brake control is set at "Apply".
- 3. The key switch is set at "Off".
- 2. The emergency and parking brake control is set at "Apply".
The powerpack assembly consists of a diesel engine, a power take-off unit, a pump drive gearbox, three hydraulic pumps, and the associated cowling and structural supports.
The engine is protected against dust and other foreign material by two dry type induction air cleaners, each with a pre-cleaner and a main filter element. As the induction air passes through the pre-cleaner most of the dust is separated out of the air and falls into a collector cup at the bottom of the pre-cleaner. Any particles not removed by the pre-cleaner are trapped by the main filter element. A service indicator shows when the main element requires servicing.
NOTE: NEVER OPERATE THE ENGINE WITHOUT THE MAIN ELEMENT IN PLACE IN BOTH AIR CLEANERS.
Waste heat from the engine is used to help keep the water spray system from freezing up in cold weather by routing the exhaust gases below the water tank. The spray nozzles and water lines in the cutter area are heated by radiation and hot air from the engine.
The belt-driven pump drive gearbox turns three hydraulic pumps; the track pump which supplies the pressurized hydraulic oil to the three track motors, the conveyor pump (a dual pump) which drives the conveyor motors, and the auxiliary pump which supplies the hydraulic oil for machine steering, elevation, etc.
A power take-off, mounted on the rear (right side) of the engine, transmits power from the engine to a belt and sheave arrangement in order to turn the cutter. The power take-off is engaged or disengaged by air pressure controlled by the cutter on-off control on the console. When the control is moved to "On", air pressure flows to the power take-off, engaging a clutch mounted between the engine and the power take-off shaft. Power from the engine is then transmitted through the clutch to the power take-off shaft. When the cutter on-off control is moved to "Off", the air pressure in the clutch is vented to the atmosphere which allows the clutch release springs to disengage the clutch.
The cutter assembly consists of the cutter and the housing.
The cutter is a cylinder (drum or mandrel) with replaceable bits mounted on auger-type flighting welded to the cylinder. The bits break the material loose and the flighting causes the loose material to move into position for discharge out the rear of the moldboard. The cutter is belt driven from a power take-off at the rear (right side) of the transversely mounted engine. The belts turn a planetary gear reducer that is inside the cutter drum, and the gear reducer turns the cutter.
The cutter drum is filled 3/4 full with a 50% solution of water and ethylene glycol antifreeze.
The cutter housing mounts to the mainframe, supports the cutter, and encloses the cutter. Nozzles in the top of the housing spray water into the housing to control the dust created by the cutting operation. A moldboard at the rear of the housing prevents material loosened by the cutter from moving back under the machine. Two hydraulic cylinders connect the moldboard to the housing and provide the moldboard with 3 inches of vertical "float". The moldboard is kept in contact with the freshly cut surface by the weight of the moldboard. The cutting edge of the moldboard is replaceable.
An air operated hammer and a punch are supplied with each machine to facilitate changing the bits when they are worn or broken. A wrench that fits on the face of the cutter sheave is also supplied, so the cutter can be turned without the engine running. The bits should be replaced as a group so that all bits are at approximately the same length. A single bit longer than the surrounding bits may damage the bit holder when the bit hits the concrete.
A manually operated bit puller is also supplied with each machine so the bits can be changed without air pressure if necessary.
The conveyor assembly consists of two separate belt conveyors; a lower or collecting conveyor and an upper or loading conveyor. Material loosened from the roadway by the cutter is funneled onto the lower conveyor which carries the material back under the machine and empties it onto the upper conveyor. The upper conveyor then carries the material up and dumps it. The upper conveyor can be positioned anywhere within an arc of 80 degrees, 40 degrees each side of center.
Both conveyors are powered by a dual unit hydaulic pump mounted on the pump drive gearbox. Each section of the pump drives a hydraulic motor which is coupled to one of the head pulleys. The head pulleys are wing type to prevent material buildup on the belts.
Two hydraulic cylinders position the upper conveyor in response to control levers in the control console; one cylinder raises or lowers the conveyor and the other cylinder swings the conveyor. Both cylinders use hydraulic oil from the auxiliary hydraulic system.
An optional remote conveyor swing control may be mounted at the left rear of the machine mainframe to provide ground level control of the upper conveyor swing.
NEVER USE THE CONSOLE MOUNTED CONVEYOR SWING CONTROL AND THE REMOTE CONVEYOR SWING CONTROL AT THE SAME TIME. ERRATIC UPPER CONVEYOR RESPONSE MAY RESULT.
NEVER STAND BEHIND THE MACHINE WHILE OPERATING THE REMOTE CONVEYOR SWING CONTROL. IF THE CUTTER HITS SOME STEEL IN THE CONCRETE OR SOME OTHER OBSTRUCTION, THE MACHINE MAY LUNGE BACKWARD A SHORT DISTANCE. ALWAYS STAND TO THE SIDE OF THE MACHINE, BEING CAREFUL TO STAY CLEAR OF THE REAR TRACK.
Water Tank And Spray System
The purpose of the water system is to wash the dust created by the cutting operation out of the air within the cutter housing. By eliminating the dust, the water system prevents a possible health and traffic hazard, makes operation of the machine easier and safer because of better visibility, and reduces required machine servicing.
It is obvious that the water spray system should be used anytime the machine is cutting.
The 700 gallon water tank at the rear of the machine is warmed by exhaust gases from the engine to help prevent freezing of the water in cold weather operations. A sight gauge provides for easy checking of the water level.
Water from the tank flows through a strainer to the belt-driven water pump, from the pump through a filter, and then to the spray nozzles located in the top and right end of the cutter housing. A pressure gauge is mounted on each side of the filter to indicate the condition of the strainer and filter. If the pressure gauge on the filter inlet falls to 30 psi with the spray nozzles in operation, the screen in the strainer should be removed and cleaned (see page 5-32). When the pressure gauge on the outlet of the filter falls to 20 psi with the spray nozzles in operation, the filter element should be changed (see page 5-22).
Anytime the machine is parked outside for a length of time in freezing weather without the engine running, the water tank should be drained, the spray system water pump drained, the water dumped from the filter body, and the optional high pressure water pump (see page 2-35) drained.
Hydraulic Oil Tanks
There are two tanks that hold hydraulic oil, a 60 gallon main tank and a 9.5 gallon replenishing tank. Oil for the hydraulic pumps is drawn from the main tank. The replenishing tank stores additional oil for use if the main tank gets low. Oil can be transferred to the main tank from the replenishing tank by using the hand operated replenishing pump. The oil passes through a 10 micron filter before it enters the main tank.
The main hydraulic oil tank has a sight gauge so that the oil level can easily be checked. A breather filter filters any air drawn into the main tank as the tank "breathes" because of atmospheric and/ system temperature changes. A breather in the top of the replenishing tank will prevent dust and other large particles from entering the replenishing tank as it breathes.
The main tank also has a magnetic filter in the tank outlet. The filter removes metal particles that may be present in the pump suction oil.
The fuel tank located just in front of the control console holds 200 gallons of fuel. A sight gauge provides easy checking of the fuel level. A manual shutoff valve is located at the bottom of the tank in the engine supply line, and another in the fuel return line that discharges excess fuel from the engine back into the tank.
The control console consists of two hydraulic panels and an electrical panel. The hydraulic panels contain the engine throttle and travel control lever and the hydraulic valves that control the various hydraulic systems and components. The electrical panel contains the engine gauges, the hydraulic oil temperature gauge, light switches, and operation switches.
Each elevation sensor consists of a patented hydraulic valve, a feeler rod and a counterweight. The counterweight position is adjustable to ensure that the feeler rod will ride firmly against the reference rod or stringline. Any change of machine elevation in relation to the reference rod or stringline will cause the feeler rod to rotate the shaft in the hydraulic valve. The rotation of the valve shaft opens a valve port which allows the pressurized hydraulic oil to flow to the end of the hydraulic cylinder that will bring the machine back into to proper relation with the reference rod. As the machine moves back to its proper position, the feeler rod rotates in the opposite direction, closing the valve port and stopping the movement of the hydraulic cylinder.
When the sensor is in the null position (there is no hydraulic flow at C1 and C2 ports) the counterweight arm should be 90° to the valve body centerline and the feeler rod should be in line with the counterweight arm.
Cross Slope Sensor (Optional)
The optional cross slope sensor (pendulum assembly) is a pendulum-type hydraulic sensor that senses any change in machine cross slope from that entered in the system. If the cross slope sensor detects a change in the machine cross slope, the sensor directs hydraulic fluid to the appropriate end of the right rear elevation cylinder to bring the machine back to the correct cross slope. The damping adjustment on the cross slope sensor can be set to meet individual needs, but "3" is generally satisfactory. The hydraulic oil temperature should be in the normal operating range before attempting to set the damping adjustment. Cold hydraulic oil will naturally slow the response of the sensor.
THE PENDULUM ASSEMBLY IS A PRECISION INSTRUMENT THAT IS ACCURATELY CALIBRATED AT THE FACTORY. DO NOT ADJUST OR CHANGE THE POSITION OF THE POINTER, THE ADJUSTMENT GUIDE BLOCK, THE ADJUSTMENT SHAFT BEARINGS OR THE BELT THAT EXTENDS FROM THE ADJUSTMENT SHAFT TO THE SLOPE INDIAVSOR. IF NECESSARY ADJUST BELT TENSION BY MOVING THE INDIAVSOR SUPPORT BRACKET. DO NOT MOVE THE ADJUSTMENT SHAFT BEARINGS.
Right Or Left Leg Slope Control (Optional)
The optional right or left leg slope control consists of a panel of hydraulic valves mounted on the right side of the control console, and the necessary hydraulic plumbing. These hydraulic valves allow cross slope sensor control of either the right rear or left rear elevation cylinder. The rear elevation cylinder not being controlled by the cross slope sensor remains in a fixed position so that the rear corner of the mainframe at that cylinder remains at a fixed distance above the cut grade (locked to grade).
ALL FOUR SLOPE CONTROL SELECTOR VALVES MUST BE POINTED IN THE SAME DIRECTION, OTHERWISE ERRATIC MACHINE RESPONSE MAY OCCUR.
NOTE: WHEN CROSS SLOPE CONTROL IS TRANSFERRED TO THE LEFT REAR LEG, THE RIGHT REAR LEG IS LOCKED TO GRADE. TO PROVIDE AN ACCURATE AND TRUE CUT, THE GRADE THE RIGHT REAR LEG RIDES ON MUST BE ACCURATE AND TRUE.