Clearwater Yarder Operator's Manual

Yarder Operation

Start Up Procedure

1. Check hydraulic oil level in reservoir. Oil should be at the "full" line on the sight gage. (Use Dexron II type hydraulic oil.)
   
   
2. Open completely all three gate valves in the charge pump suction lines between the tank and the pump (figure 5).
   
   
3. Check engine oil, water, and fuel levels. If necessary, fill according to the engine manufacturer's operator's manual.
   
   
4. Disengage clutch.
   
   
5. Turn engine ignition switch on and start engine. Allow engine to warm up briefly before engaging the clutch. (For more detailed starting instructions see engine manufacturer's maintenance and operator's manual.)
   
   
6. Immediately after engaging clutch, check all three charge pump pressure gages (figure 5) and the back pressure gage located in the hydraulic return line. The charge pump pressure should read greater than 100 psi at engine idle (figure 5) Note: If no pressure is indicated in anyone of the three systems, immediately disengage the clutch and repeat steps 1 and 2. Charge pump pressures less than 100 psi would indicate a charge pump malfunction.

Figure 5—Drag and circulation system.

The back pressure in the hydraulic return line should not exceed 30 psi. If the back pressure gage is indicating 30 psi or more, reduce the engine speed and allow the hydraulic oil to warm up to approximately 85° F before increasing engine speed or attempting to operate the yarder. The temperature gage is on the side of the hydraulic reservoir.

Operating the system without charge pump pressure will damage the main pump. Operating the yarder at a return pressure (back pressure) greater than 30 psi will damage the hydraulic motor shaft seals. High return pressure can be caused by operation of the system at a hydraulic oil temperature.

Raising and Lowering Mast

Do not attempt to raise or lower the mast without first insuring that the hydraulic cylinders attached to the mast are free of air and full of hydraulic oil. This is especially important if the system has not been raised for a long time, that is, 30 days, or if the hydraulic oil has been lost or removed from the system for any reason.

Figure 6—Mast raising/lowering mechanism

To fill the hydraulic cylinder:

1. Secure the mast in its current position.
   
   
2. Disconnect the hydraulic cylinders from the mast (figure 6).
   
   
3. Support the cylinders so subsequent extension/retraction will not damage equipment or personnel.
   
   
4. Hydraulically extend/retract the cylinder a minimum of six times to fill the cylinders with oil and purge any air. This should be done with the engine at full throttle. Each cylinder should be fully extended and pressurized to about 2,000 psi each time.
   
   
5. Reconnect the cylinders to the mast.

To raise the mast:

1. Yarder must be approximately level before attempting to raise the mast.
   
   
2. Inspect the mast raising/lowering hydraulic system and mechanisms (figure 6), including cylinder and attachment points for leakage, damage, or excessive wear. Make appropriate repairs before attempting to raise or lower the mast. Make sure that the four cylinder clevis pins are in place and properly secured with their retaining clips.

If hydraulic oil has been removed, drained, or if parts have been removed, follow the procedure to fill hydraulic cylinders before continuing.

3. Clear all personnel and obstacles out of the path of mast's rotation.
   
   
4. Make sure all cables are free and positioned so that they will not become tangled or caught while the mast is being raised.
   
   
5. Set engine throttle wide open.
   
   
6. Slowly move the handle of the mast directional valve (figure 4) to the "raise" position.

Check the mast lowering speed for proper operation each time the mast is raised. This is accomplished by stopping the mast after it is about 6 inches above the mast cradle and observing the time required to lower the mast back to the cradle. If the mast lowers much faster than it raises, check the system for leaks or damaged parts.

7. When the mast is fully up, move the lever to the "stop" position immediately to prevent undue stress in the raising mechanism.
   
   
8. Secure the mast in the upright position by securing the three bolts opposite the hinge pin (figure 7).
   
   
9. Secure all four guylines and make sure each anchor is adequate.

Figure 7—Secure mast.

Important. The minimum distance between each guyline's anchor and the mast shall be 50 feet, or the angle between a horizontal line from the anchor to the mast and the guyline shall be less than 35°. The rear guyline shall be in line and opposite to the skyline. The forward guyline should be located under and slightly off to the side of the skyline to allow passage of the carriage. The side guyline shall be on each side and rearward of the mast.

The completed guy line anchoring system should look like a chicken's foot when viewed from above.

10. Plumb the mast using the pointers provided on the mast (figure 8). This is accomplished by tightening the appropriate guyline.

To lower the mast:

1. Inspect mast hydraulic system as in Step 2 for raising the mast.
   
   
2. Release all guylines and check to see that all cables are free and positioned such that they will not become tangled or caught while the mast is being lowered.
   
   
3. Clear all personnel and obstacles out of the path of rotation of the mast.
   
   
4. Set engine throttle wide open and momentarily move the mast directional valve handle to the "raise" position until approximately 2,000 psi is read on the hydraulic system pressure gage, then move handle to the "stop" position.

Figure 8—Plumb mast.

This step is used to check the functioning of the hydraulic system; if the system cannot develop 2,000 psi, check for leaks or damage and make necessary repairs. Then follow the procedure for filling the hydraulic cylinders before continuing.

5. Remove the three bolts opposite the mast hinge pin (figure 7).
   
   
6. Move the mast directional valve lever to the "lower" position, and hold until the mast contacts the cradle. The mast can be stopped at any time by moving the lever to the "stop" position. However, this is not recommended because of shock loads.
   
   
7. Immediately after the mast is resting in the cradle, move the lever to stop position to prevent undue stress from building up in the mechanism.
   
   
8. Secure all lines to the yarder.

Adjusting Line Pull

Maximum line pull is determined by the maximum hydraulic pressure available. The maximum hydraulic pressure in the skyline, mainline, and haul back hydraulic circuits is determined by the pump high pressure relief valve setting. These high pressure relief valves must be adjusted so the bare drum line pull cannot exceed 7,500 pounds for the skyline and 3,500 pounds for the mainline and haulback winches.

Failure to adjust the high pressure relief valve will allow the winches to exceed line pull specifications and overload the cable, causing it to break prematurely.

To adjust the bare drum line pull for the respective system, a dynamometer or other suitable device that can accurately measure line tension must be used. The hydraulic oil must be at about 100° F and the engine running at full throttle: 2,800 rpm. The line pull is adjusted as follows:

1. Secure all four guylines to adequate anchors and remove all of the cable except about one-half of the first layer on the winch drum.
   
   
2. Secure the dynamometer to the end of the cable and to a suitable anchor.
   
   
3. Loosen the locking nut on the high pressure adjustment screw (figure 9). (The relief valve adjustment screw is on the side of the pump opposite the high pressure outlet connection.)
   
   
4. With the engine at full throttle, slowly move the manual controller to bring the line in.
   
   
5. Observe the dynamometer reading and adjust the relief valve until the desired line pull is obtained (7,500 pounds for the skyline winch and 3,500 pounds for the mainline and haul back winches).
   
   
6. Tighten the relief valve locking nut and repeat steps 4 and 5 several times to verify the value of line pull.
   
   
7. Note this system hydraulic pressure at maximum line pull and record this pressure. It can be used in the future to verify the setting of the relief valve.

Any time the relief valve is disassembled for maintenance or the valve adjustment has been altered for any reason, repeat the above adjustment procedures.

Figure 9—Pump and controls.

---

Top

Back | Next

Cover Page