MODEL V1433XL, V1433 MODEL V1833XL, V1833 - MinnPar

-----------------------------------------~Drive DirectionalControl ValveCreep SpeedSolenoid ValveUr---,/Flow Divider/CombinerFIG. 4Creep SpeedNeedle ValveDRIVE FUNCTION (cont'd)Pump flow circulates through the main valve assembly and back to tank if no functions areactivated when the pump is running. Once the directional control valve shifts, fluid is directed to oneof the load control valves in its free-flow direction, and then to the normally open positraction valve.Fluid flows through the positraction valve cartridge, then to both drive motors which each have an 8.0cubic inch per revolution displacement and are located on the steer axle.The deceleration valve is utilized to cushion the braking action of the drive circuit. This isaccomplished by letting fluid by-pass between the two drive motors. Since the deceleration valve is a2-way normally open spool valve, it allows fluid to flow through it at all times. When the drive controlhandle is actuated, energizing the drive circuit, the deceleration valve becomes energized and closes,blocking the flow of fluid through it. When the drive handle is released (circuit de-energized), thedeceleration valve opens, and lets the drive pressure by-pass to the opposite drive motor, allowing thetwo drive motors to continue to roll momentarily without creating a hydrostatic lock in the circuit. A0.040 dia. orifice, located under the deceleration valve, is used to control the amount of by-pass thatoccurs which affects the deceleration of the machine.The 2633 has a creep speed which is either automatically activated at platform heights aboveseven feet by a limit switch, or is operator selectable at heights below seven feet. Creep speed is a situationin the drive circuit whereas when the creep speed solenoid valve is energized, some of the drive flow isdiverted back to the tank. The speed at which the machine travels when in creep, is controlled by the creepspeed needle valve (See FIG. 4). The creep speed is factory set to obtain a travel speed of 80-1 00 sec/88 feet, on firm, level ground; (Ref.. 75/.6 mph), (see note #2 on schematic at end of hydraulic section).MANUAL 92370-002November 1997