Single Action and Double Action Pilot Oil Lines
Illustration 1 | g00376612 |
(A) SINGLE ACTION position (B) STOP position (C) DOUBLE ACTION position (1) Cab floor (2) Pedal assembly (3) Lock pin (4) Spring pin (5) Pilot control valve |
Illustration 2 | g00465629 |
Pilot control valve (attachment) (5) Pilot control valve (attachment) (6) Port (port to tank) (7) Port (port from hydraulic activation control valve) (8) Port (port to top of main control valve) (9) Port (port to bottom of main control valve) |
Pilot oil from the hydraulic activation control valve enters pilot control valve (5) through port (7) . Port (6) on the pilot control valve returns the pilot oil to the hydraulic tank when the hydraulic control pedal is not activated. Oil is directed to the top of the main control valve through port (8) . Oil is directed to the bottom of the main control valve through port (9) .
Single Action Hydraulic Attachment
With a single action hydraulic attachment, the lock pin must be placed in the SINGLE ACTION position (A) . Supply oil is directed to the pilot control valve from the hydraulic activation control valve. The supply oil enters the pilot control valve through port (7) . Port (9) on the pilot valve is not used for single action hydraulic attachments. Port (8) sends pilot oil to the top of the main control valve. The pilot oil at the main control valve shifts the control valve stem downward.
Double Action Hydraulic Attachment
With a double action hydraulic attachment, the lock pin must be placed in the DOUBLE ACTION position (C) . Supply oil is directed to the pilot control valve from the hydraulic activation control valve. The supply oil enters the pilot control valve through port (7) . Port (8) sends pilot oil to the top of the main control valve. The pilot oil at the main control valve shifts the control valve stem downward. Port (9) sends pilot oil to the bottom of the main control valve. The pilot oil at the main control valve shifts the control valve stem upward.
One Pump and Two Pump Pilot Oil Lines
Illustration 3 | g00465696 |
(10) Port (pilot line for two pump flow) (11) Ball valve (selector valve for either two pump or one pump flow) (12) Pilot valve (13) Pilot oil manifold (14) Main control valve (15) Port (pilot oil to hydraulic tank) (16) Port (pilot oil supply) (17) Port (pilot oil line) (18) Port (pilot oil to boom control valve) (19) Port (pilot oil to tank) |
The pilot oil lines control the front pump oil flow to the attachment circuit. When the attachment requires a large pump flow, the two pump flow control can be activated. Illustration 3 shows an auxiliary system with optional two pump flow or one pump flow. Ball valve (11) is a selector valve. Two pump flow and one pump flow can be selected by ball valve (11) . Without ball valve (11) , the operator can operate in two pump flow with pilot valve (12) . Pilot valve (12) provides two pump flow to the boom cylinders. When an increase in hydraulic oil is needed for boom operation, pilot valve (12) allows pilot oil to control additional pump oil to the boom cylinders.
Illustration 4 | g00537847 |
(E) One pump flow (F) Two pump flow (11) Ball valve (selector valve for two pump flow or one pump flow) (20) Swing drive |
When the lever for ball valve (11) is in position F, two pump flow is selected. When the lever for ball valve (11) is in position E, one pump flow is selected.
Two Pump Flow Only
Systems that only have pilot valve (12) operate in two pump flow. These systems do not have ball valve (11) .
Illustration 5 | g00465721 |
(10) Port (pilot line for two pump flow) (12) Pilot valve (13) Pilot oil manifold (14) Main control valve (15) Port (pilot oil to hydraulic tank) (16) Port (pilot oil supply) (17) Port (pilot oil line) (18) Port (pilot oil to boom control valve) |
Pilot oil from port (16) of pilot oil manifold (13) is sent to port (17) of main control valve (14) . When the attachment control is not activated, the pilot oil goes through the attachment control valve and back to the drain. The drain line is through the main control valve. When the attachment control is activated, the control valve stem shifts. This blocks the flow of pilot oil around the stem. The pilot oil pressure increases.
Illustration 6 | g00465967 |
(10) Port (pilot line for two pump flow) (12) Pilot valve (22) Port (pilot oil supply) (23) Port (pilot oil from boom control lever) (24) Port (drain to pilot oil manifold) (25) Port (supply to bottom of main control valve) |
Illustration 7 | g00465726 |
(12) Pilot valve (21) Spool (22) Port (pilot oil supply) (23) Port (pilot oil from boom control lever) (24) Port (drain to pilot oil manifold) (25) Port (supply to bottom of main control valve) (26) Spring |
The pilot oil goes to port (22) of pilot valve (12) . The pilot oil is directed through pilot valve (12) to port (10) . The pilot oil pushes the control stem for the Boom II in the upward direction. The control stem for the Boom II is in the main control valve. The movement of the control stem upward restricts load sensing pressure to the rear pump. The movement of the control stem also restricts pump oil to the boom cylinders. Pilot oil is directed to the control valve for the Boom II when the boom control lever is operated. At the same time, pilot oil goes to port (23) of pilot valve (12) . The pilot oil shifts spool (21) . The spool redirects pilot oil from port (10) to port (15) . Port (15) sends the pilot oil to the hydraulic tank. The two pump pilot oil circuit provides more hydraulic oil to the boom cylinders. More hydraulic oil is needed at the boom cylinders during increased loads. As the load increases and more hydraulic oil is needed at the boom cylinders, the pilot oil shifts spool (21) . The pilot oil from the implement control lever forces the control stem for the Boom II downward. Additional pump oil is provided to the boom cylinders.
The attachment does not get front pump oil when the boom raise circuit is fully activated. The boom circuit has priority over the attachment circuit.
The attachment receives additional pump oil from the rear pump when the load increases to a set amount. A check valve determines when oil from the rear pump is provided to the attachment. The check valve is located in the lines from the main pump. Refer to System Operation, "Combined Function Hydraulic Operation (Front Lines Group)" for information on two pump flow for the attachment.
One Pump Flow Only
Standard machines are equipped with one pump flow. The function of one pump flow does not provide additional pump oil to the boom cylinder or the attachment. No rear pump oil is provided to the attachment during one pump flow. Refer to System Operation, "Pump Hydraulic System" for more information on standard one pump flow.