HP750 Processor Head Caterpillar

Saw Unit

Usage:

Show/hide table




Illustration 1	g00751354

The cutting unit consists of a saw motor, a saw bar, a saw chain, hydraulic valves and a saw bar cylinder. The saw motor is mounted to the frame. The saw motor drives the chain via a sprocket on the output shaft. The saw bar is operated by a hydraulic cylinder.

A chain catcher is mounted on the extension of the shaft of the saw motor. In order to obtain an optimal cutting speed, the saw feed is controlled by hydraulic oil pressure.

The saw chain is lubricated by a pump that is mounted on the built-in oil tank on the frame.

The head is equipped with a Saw-98B saw.

Saw Chains and Bars

Show/hide table

It is possible for the frame of the harvester head to fall when parked in the vertical position. To avoid personal injury or death and equipment damage, fasten the safety chain to the frame and the felling link. Secure the chain in an appropriate manner.

Show/hide table

Never use dull or worn saw chains. Never use worn or damaged saw bars.
Personal injury or death can result.

Always follow the manufacturers recommendations and requirements regarding the proper use and maintenance of saw chains and saw bars.

Maintenance of the Saw Chains

Show/hide table

Accidental machine starting can cause injury or death to personnel working on the machine.
To avoid accidental machine starting, turn the battery disconnect switch to the OFF position and remove the key. If the machine is not equipped with a battery disconnect switch, disconnect the battery cables from the battery and tape the battery clamps.

Place a do not operate tag at the battery disconnect switch location to inform personnel that the machine is being worked on.

Show/hide table

Never use dull or worn saw chains. Never use worn or damaged saw bars.
Personal injury or death can result.

Always follow the manufacturers recommendations and requirements regarding the proper use and maintenance of saw chains and saw bars.

Keep the chain sharp. This will create less wear on the chain and the bar.
Before you install a new chain coat the chain with oil.
Watch for saw dust. Saw dust indicates that the saw chain is dull or worn.
Always keep the proper tension on the chain.

Maintenance of the Saw Bar

The life of the saw bar increases if the saw bar is adjusted correctly. Therefore, consider the items below:

Check that the chain groove and the oil hole of the bar are not blocked when the chain is replaced.
Check the saw bar for excess wear when the chain is replaced. If the bar is worn, turn the bar or replace the bar.
Grind the guides on the saw bar to an even height, if necessary.
In order to avoid cracking, remove burrs on the outside of the guides.
Do not use the saw for long periods of time. This makes the saw bar hot. This will increase the risk of cracks in the saw bar. Do not use the saw continuously for more than five seconds.
Change the nose sprocket, if necessary. The play should not exceed 0.2 mm (.008 inch).
Check the rivets of the nose sprocket.

Adjust the Home Position of the Saw

The home position of the saw can be set by adjusting the pivot head at the end of the cylinder rod. Loosen the locknut and adjust the pivot head by turning the rod. When the saw bar is in the home position, the bar is clear of the tree. The saw chain will not hit the plates in the housing. Tighten the nut after adjustment.

Adjust the Speed and Pressure of the Saw Bar

In order to obtain a quick clean cut, the feed of the saw bar must be adjusted properly.

The speed is determined by a restrictor in the inlet on the "PLD" valve. The valve is positioned under the right hand manifold block. The force of the feed of the saw bar is set by adjusting the pressure on the "PLD" valve, which is a relief valve.

Set the pressure of the saw bar as high as possible and then cross cut a large tree with a sharp chain. The speed of the saw motor should not decrease. If the pressure of the saw bar is set too high, the force of the saw bar against the tree will stall the saw motor. If the pressure of the saw bar is set too low, the cross-cutting will be slow.

Replace the Magnetic Sensor for the Saw

The sensor is locked in place by a spring that is held by a small metal tab.

Loosen the screw that holds the tab, and remove the tab. Remove the sensor.

Remove the spring from the cable of the sensor. Install the spring on the cable of the new sensor. Install the new sensor.

Chain Lubrication

The lubrication pump for the chain is mounted on the frame near the saw motor.

The tank is integrated in the frame. Fill the tank through the hole on the right side of the main frame. The hole is located just below the lower pin for the felling link cylinder. Place the head in the down tilt position.

Note: Fill the tank with oil. Do not get dirt in the tank.

A filter is mounted inside the lubrication pump. Remove four screws (18) that hold the pump. Remove the filter. Clean the filter after every 250 working hours.

The harvester head is equipped with an adjustable pump EASY GREASY. The pump is electrically operated. The pump flow can be adjusted between 0 to 0.7 cubic centimeters per second.

The flow is adjusted with a control unit in the cab.

The pump will also continue to deliver oil for two seconds after the saw becomes inactive. This will get the oil to the bar, when the bar is not under pressure.

If a separate control unit is used for the EASY GREASY, use the following factory settings.

Time range 0 to 1.2
The unit of time is seconds.
The mode selection is "B".

Troubleshooting EASY GREASY

The pump can be tested while the engine is OFF and the control system is ON.

Press the saw button. Check the flow from the pump.

EASY GREASY has only four moving parts: the magnetic anchor, the piston and the discs of the two check valves.

If the pump is not functioning properly check the following conditions:

broken wires
dirt in the filter
dirt in the check valves of the pump

Symptom Procedure

Oil is leaking out of the saw even though the saw is not activated. Clean the two nonreturn valves in the pump.

Note: Do not damage the O-rings.

Insufficient Flow

Clean the filter.

Check the viscosity of the oil.

No Flow

Determine whether the cause is electric or mechanical.

Check for current to the pump when the saw is active. Also check the solenoid.

If the cause is not electric, disassemble the pump and clean the pump thoroughly.

Saw - 98B

The Saw - 98B consists of a saw motor unit, a bearing unit, and a bar holder unit.

Show/hide table




Illustration 2	g00751768
Saw Motor Unit (1) Mounted flange (2) Cover (3) Bar holder (4) Shaft (5) Drive (6) Shims (7) Washer (8) Chain catcher (9) Shaft (10) Thrust plate (11) Excenter (S) (11B) Excenter (M) (12) Eccentric pin (15) Screw (16) Screw (17) Screw (18) Screw (23) Washer (24) Washer (26) Pin (27) Pin (28) Pin (29) Pin (33) O-ring (37) Bearing (39) Saw motor

The saw motor unit consists of a fixed mounted hydraulic motor (39). A chain drive sprocket and a chain catcher (8) are mounted on the motor shaft. The motor unit is fixed to the saw unit by two allen head screws (15) .

The bearing is a special type of ball bearing (37). One groove of bearing (37) is mounted in flange (1). This is the outer ring of the bearing. The inner ring of the bearing is mounted in the groove of bar holder (3) .

The bar holder unit consists mainly of bar holder (3) with shaft (9), thrust plate (10) and two excenters (11) and (12). One of the excenters is for clamping the bar and one is for the tension of the chain.

Function of the Bar Holder and Tensioning Device

Show/hide table




Illustration 3	g00751772
Saw Bar Holder (9) Shaft (10) Thrust plate (11) Excenter (S) (12) Eccentric pin (26) Pin (28) Pin

The saw bar is kept in place via friction that is created when eccentric locking pin (12) clamps the bar between bar holder (3) and thrust plate (10) .

The locking shaft is mounted in a hole through shaft (9 ). The shaft has one flat surface.

The shaft is fixed to the bar holder by two cylindrical pins.

Tensioning excenter (11), thrust plate (10), and the saw bar are located above the locking shaft.

The bar is being held in place by friction, and by one pin (28) in the thrust plate. The pin fits into the corresponding hole in the saw bar.

The pin should be mounted in the outer hole on the side that cuts the tree.

When the locking shaft is in this position, the flat surface is facing the thrust plate. The maximum play between the thrust plate and the saw bar holder is obtained. In this position, the distance between the tips of pin (28) and the bar holder is sufficient to be able to pull out the saw bar. This position is called the bar changing position.

Show/hide table




Illustration 4	g00751781
View from the Saw Bar Nose (3) Bar holder (9) Shaft (10) Thrust plate (11) Excenter (S) (12) Eccentric pin (26) Pin (28) Pin (29) Pin

Use the tensioning excenter (S) or the tensioning excenter (M) in order to set the tensioning distance of the bar.

Turn the clamping shaft clockwise. This will increase the pressure against the thrust plate and the saw bar. The friction will fix the bar in position.

In order to obtain an adequate pressing force, the excenter has been designed so that the excenter total tensioning distance is 1.4 mm (.055 inch). Label (S) is the standard tensioning excenter. This is the nominal tensioning distance for the excenter. The distance is between 4.8 mm to 6.2 mm (.19 inch to .24 inch). The thickness of the bars that are available may vary between 5 mm (.2 inch) and 6.4 mm (.25 inch).

In order to be able to see the difference, the hexagon part is marked with the letter (S). This is for a tensioning between 4.8 mm (.19 inch) and 6.2 mm (.25 inch). The hexagon part is marked with the letter (M) for tensioning between 5.5 mm (.22 inch) and 6.9 mm (.27 inch). The setting that should be used depends on the thickness of the bars.

Tensioning Device

Show/hide table




Illustration 5	g00751795

The saw bar is mechanically connected to the thrust plate with pin (28). The saw bar moves inward with the plate. The saw bar moves outward with the plate.

The thrust plate is held by shaft (9). The shaft also holds the tensioning excenter. The tensioning excenter presses against the outer edge of the thrust plate. This is designed so that the tensioning excenter is self-locking. The excenter can not be forced inward by external forces.

Show/hide table




Illustration 6	g00751809
Position One

The hole for the locking shaft is not centered between the two holes of shaft (9) .

By mounting shaft (9) in different ways, the center of the piece will be located at different distances from the shaft of the saw motor.

The mounting direction is shown in Illustration 6.

The shaft can be mounted in different ways. The bar, the chain drive sprocket, and the chain affect the mounting of shaft (9) .

The first position is the distance from the center of the saw motor shaft to shaft (9). This distance is 86 mm (3.4 inch). The second position is the distance from the center of the saw motor shaft to shaft (9). This distance is 96 mm (3.8 inch).

The tensioning of the chain is achieved by turning the tensioning excenter clockwise until the desired tension of the chain is achieved.

Tensioning of the Chain or Replacing of the Chain and Bar

Show/hide table

Never use dull or worn saw chains. Never use worn or damaged saw bars.
Personal injury or death can result.

Always follow the manufacturers recommendations and requirements regarding the proper use and maintenance of saw chains and saw bars.

Use the tool (part number 522260) that was delivered with the saw unit. The tool is a 16 mm (.6 inch) spanner socket.

Tensioning the Chain

Lessen the clamping force of the thrust plate by turning the locking shaft counterclockwise. Turn the shaft until the bar loosens.

Adjust the tension of the chain by turning the tensioning excenter. Use the socket.

Clamp the saw bar in position by turning the locking shaft clockwise.
Note: Do not adjust the tension of the chain too much. The tensioning excenter is self-locking. The bar can not be forced inward. Do not overtighten the chain. This will cause the bar and/or the chain to quickly wear out.

Changing the Chain and Bar

Loosen the clamping force of the bar. Then turn the tensioning excenter so that the flat surface of the excenter faces the tip of the saw bar.

Remove the chain.

Press the thrust plate against the locking shaft and lift the saw bar somewhat so that the bar goes free of the two pins in the thrust plate. Pull out the saw bar.

In order to install a new bar, the two pins in the thrust plate must fit into the holes on the saw bar.

Turn the locking shaft until the bar is slightly clamped.

Install the chain. Adjust the tension of the chain.

Service Saw Motor Unit

Replace the Chain Catcher

Show/hide table




Illustration 7	g00751830
Saw Motor (5) Drive (6) Shims (7) Washer (8) Chain catcher (15) Screw (18) Screw (23) Washer (24) Washer (27) Pin (39) Saw motor

Remove screw (18) on the end of the motor shaft. Remove chain catcher (8) .

Install a new chain catcher (8) and install screw (18). Do not forget to install the Nordloc washer.

Replace the Chain Drive Sprocket

Remove the chain.

Remove the chain catcher.

Pull off the sprocket.

Install a new sprocket. Check the necessity of shims (6) when the chain drive sprocket is assembled.

When closed drive sprockets are used, it is necessary that the center of the sprocket is lined up with the groove of the saw bar. Use a ruler to check that the center of the sprocket is lined up with the groove of the saw bar. If this is not the case, install shims on the upper side of the sprocket.

Reinstall the chain catcher.

Grease the Saw Motor

Remove the plug. Install a grease nipple (R1/8 BSP). Fill the saw motor with grease until grease comes out of the saw motor unit beside the motor shaft. Use the same grease that is used on the carrier.

Replace the Saw Motor

Remove the bar and the chain.

Disconnect all the hydraulic hoses and plug all the hydraulic hoses from the motor.

Remove the complete motor unit by loosening screws (15). Remove all the parts from the shaft of the motor and the fittings. Install all the parts and the fitting to the new motor.

Fill the housing of the motor with oil.

Install the motor unit, and check for the necessity of shims for the sprocket.

Service the Saw Bar Holder Unit

Removing and Installing the Locking Shaft

Show/hide table




Illustration 8	g00751840
Bar Holder Unit (3) Bar holder (9) Shaft (10) Thrust plate (11) Excenter (S) (12) Eccentric pin (26) Pin (28) Pin (29) Pin

Locking pin (12) is held in place in shaft (9) by pin (29). Use a 6 mm (.24 inch) punch in order to remove the pin that holds the locking shaft before you remove the locking shaft. Always lubricate the center surface of the locking pin before you install the pin. Before you install the pin in the locking shaft, see Illustration 8.