1.21.1. Auger/Conveyor Hydraulic System

TM 5-3895-373-20 1.21.1. Auger/Conveyor Hydraulic System. The auger/ conveyor drive system consists of electrical controls on both the left and right screed control panels, control switches on the operator switch panel, auger/conveyor control valve, speed control valve, left and right auxiliary hydraulic pumps, and feed limit switches. The left and right auger/conveyor control circuits are identical. The following description applies to both sides. Electrical power for the auger/conveyor drive system is from CB6 to the screed control panel. The feeder control switch on the screed control panel passes the current to the auger/ conveyor switch on the operator switch panel. The three position switch on the operator switch panel allows for manual control, automatic control, and an off position. When the feeder control switch on the screed control panel is turned on, and the auger/conveyor reverse control switch is in normal, power is sent to the auger/conveyor switch on the operator switch panel. With MAN selected on the auger/ conveyor switch, the auger/conveyor control valve forward solenoid is actuated and positions the auger/ conveyor control valve. When the auger/conveyor switch on the operator switch panel is placed up, "AUTO" position, power is sent to the feed limit switch mounted on the end gate of the screed. When an insufficient amount of paving material is in the auger chamber the limit switch will be closed. This allows power to pass through the limit switch and energize the auger/conveyor control valve forward solenoid. The solenoid is energized and the valve shifts to the forward position. When the paving material reaches a sufficient level in the auger chamber, the paving material actuates the feed limit switch. The current path to the auger/conveyor control valve forward solenoid is broken. The auger/conveyor control valve forward solenoid is deenergized and the valve returns to the center, off, position. For reverse operation of the auger/conveyor system, the feeder control switch on the screed control panel must be in the center OFF position. This removes power from the auger/conveyor control valve forward solenoid. When the auger/conveyor reverse control switch is placed in the up, REVERSE position, power is sent to the auger/conveyor control valve reverse solenoid. The solenoid energizes and repositions the valve to the reverse position. Hydraulic oil for the auger/conveyor drive system is supplied by the auxiliary hydraulic pumps. The left and right auxiliary hydraulic pumps each consist of two pumps, a 0.7 and a 0.58 cu in. (11,5 and 9,5 cc) output, mounted on a common shaft. The 0.7 cu in. (11,5 cc) pump on each side supplies hydraulic oil to the respective sides auger/conveyor drive system. The 0.58 cu in. (9,5 cc) pump on the left auxiliary hydraulic pump provides oil to a 50/50 flow divider. The flow divider splits the output of the pump and delivers half of the flow to each side of the auger/conveyor drive system. The hydraulic oil from the hydraulic pumps is sent to a speed control valve and a test manifold. The test manifold allows the measuring of pressure on the outlet of the hydraulic pumps. The speed control valve is an adjustable relief valve. The valve regulates the speed of auger/conveyor drive motor by regulating the pressure of the hydraulic oil sent to the motor. Excess hydraulic oil from the speed control valve is relieved to the return manifold. The output of the speed control valve is sent to the auger/ conveyor control valve. The control valve is protected by a 2750 psi (18 961 kPa) relief valve internal to the control valve. The control valve is equipped with two solenoids to position it for forward and reverse. When neither solenoid is energized, the control valve is in the center, off, position. The input and return ports are cross connected allowing hydraulic oil entering the valve to go immediately out the return port to the return manifold. When the forward solenoid is energized, the control valve is positioned to the forward position. This position sends the incoming hydraulic oil to the forward port on the auger/ conveyor drive motor, causing the motor to rotate in the forward direction. When the reverse solenoid is energized, the valve is repositioned to the reverse position. The control valve sends the incoming hydraulic oil to the reverse port on the hydraulic motor, causing the motor to turn in the reverse direction. The output shaft on the auger/conveyor drive motor is attached to a drive sprocket wheel and chain. The chain drive system allows the hydraulic motor to provide the mechanical power for both the conveyor and auger systems. 1-42