Note: The two pump flow system can be used with an attachment.
The one-way hydraulic flow system is for attachments that require one-way pressurized hydraulic flow. A hydraulic hammer is a good example. The following components are the main components of the one-way hydraulic flow system:
- Pilot oil lines
- Hydraulic control group
- Front lines
- Attachment relief valve
The operation of the main control valve is identical to the standard control lines.
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| Illustration 1 | g00376612 |
(A) SINGLE ACTION position (B) STOP position (C) STORAGE position (1) Cab floor (2) Pedal assembly (3) Lock pin (4) Spring pin (5) Pilot control valve | |
The hydraulic control group is bolted to cab floorplate (1) on the left side of the travel pedal. The hydraulic control group consists of pedal assembly (2) and pilot control valve (5) . The pilot control valve is identical to the travel pilot control valve.
To use the one pump flow system, pin (3) must be in SINGLE ACTION position (A) . With the pin in this position, the pedal can only be depressed forward. With pin (3) in the SINGLE ACTION position, backward movement of the pedal is stopped.
If the one pump flow system is not needed, pin (3) should be placed in STOP position (B) . With pin (3) in the stop position, the operator can use the pedal as a foot rest.
When hydraulic activation control valve (6) is activated, pilot oil is sent to port (16) of pilot control valve (5) . The pilot oil at port (16) goes into passage (18) .
When pedal (8) is rotated forward, the pedal pushes on rod (9) and on seat (10) against the force of springs (11) and (12) . Stem (14) opens passage (15) to passage (18) .
As passage (15) is opened, the pilot oil in passage (18) goes through the following passages: passage (15), the passage in stem (14) and out port (17) . The pilot oil goes to main control valve (7) at the top of the attachment control valve. The pilot oil pressure moves the stem. The stem then sends pump oil to the attachment through line (21) . Oil returns from the attachment through line (20) .
The oil pressure is controlled by the relief valve. The relief valve is located on the boom for the single action circuit. The pressure setting is 17000 ± 500 kPa (2465 ± 70 psi) .
Note: The relief valve pressure setting must be reset to the proper specification for the attachment that is being used.
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| Illustration 2 | g00377153 |
Pilot lines (5) Pilot control valve (6) Hydraulic activation control valve (7) Main control valve | |
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| Illustration 3 | g00377134 |
Pilot control valve (8) Pedal (9) Rod (10) Seat (11) Spring (12) Spring (13) Return port (14) Stem (15) Passage (16) Pilot oil supply port (17) Port (18) Passage | |
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| Illustration 4 | g00377154 |
Front lines (7) Main control valve (20) Return line from attachment (21) Supply line to attachment | |