REED 00 C50SS, Manual, Page: 47 / 84

REED
00 MODEL:
C50SS
TRAILER CONCRETE PUMP
MAINT
PAGE 17
CIRCUIT OPERATIONAL SEQUENCE
In the operational sequence of the MAIN PUMP CIRCUIT and with the engine running and
throttle adjusted to maximum, the main pump is idling. When the PUMP switch is placed
ON and volume control open, the hydraulic drive cylinders begin to cycle.
The cylinder to receive the flow from the hydraulic pump, the one being pressurized, is the
one moving forward or the one with the rod fully retracted and ready to extend. In this
example,
CYL “A” . Cylinder “A” extends and at full extension, the sensor of CYL “B” is
activated, sending a signal to the black box, which then sends a signal to the PCP valve.
This valve causes the position of the swashplate to be changed and CYL “B” is being
pressurized and extends. The signal from the sensor, is also used to shift the S-TUBE to
CYL “B” . (This is explained in the Shift Circuit Description). This alternating cycling takes
place continuously until the PUMP switch is turned OFF .
It can be noted in the schematic and diagram above, that the main pressure and flow is
only directed to one side of the hydraulic drive cylinder. In this instance, it is directed to the
barrel end of the cylinder. To establish the closed loop, the rod side of the cylinders are
connected together. The purpose of this arrangement, is to transfer the hydraulic oil from
one to the other, during the extension/retraction stroke. In example: As
CYL “A” is being
extended, the oil on the rod side of the cylinder is forced out and is directed to the rod side
of
CYL “B” , causing the rod to retract. The fluid that is in the barrel end of CYL “B” is
forced back to the pump.
REVISION: