Brief History

Rotation Circuit Page 6 Chapter 7 DDRH Rotary Head (early style)

Early CM 760 and CM 780 units were manufactured with the latest version of the DDRH rotary head. This style head is fitted with a top mounted air swivel arrangement. The rotary motor drive system is a direct drive 64 in.³ (1048 cc) radial piston motor. The rotary head uses the breakout sleeve system for pipe thread breakout. The air swivel is fitted with chevron packing. A hand-operated grease gun is required to keep the packing loaded. The grease fitting in the packing housing does not have a built in check valve so excessive grease pressure cannot be applied.

Note: Do not use standard grease fittings in place of the point indicated with the red arrow. Remove the spring and ball from the fitting so excessive grease pressure cannot be applied to the packing.

Spindle adapter

The spindle adapter is the replaceable part found in the end of the rotary head hollow shaft. It has 3 1/2 API male thread to engage the spindle and the female thread will either be 2 or 2½ Z thread.

Replacing the Spindle Adapter

The spindle adapter is a wear part that will require replacement. This can be accomplished with the rotary head at the bottom of the drill guide and the guide vertical. Allow some space below the lowered head for removal of the parts. Blocking should be installed under the rotary head mounting plate for additional safety.

Removal and replacement of the spindle adapter requires the removal of the front housing and rod lock sleeve. This will expose the adapter, which is threaded into the end of the rotary head spindle.

1. Vent the air pressure from the hydraulic tank by removing the pressure gauge temporarily. Apply a vacuum to the vent port on the hydraulic tank if available. Remove all of the hydraulic lines from the lower section of the rotary head. Plug, cap and tag all open hoses and connections. Remove the rod lock housing by removing the 12mm socket head screws from the bottom. There are two threaded holes that can be used for drawing the front housing loose. The rod lock sleeve may come out with the lower housing so be careful, as these parts are heavy. With the lower housing and rod lock sleeve removed, the flats on the spindle adapter are now accessible.

2. The rotary head spindle must be locked before the adapter can be removed. Use capscrews from the rod lock housing to install the locking plate (52129111). The locking plate slips over flats machined into the spindle. The spindle may need to be rotated to align the threaded holes in the bearing housing with the locking plate.

3. Attach the appropriately sized “J” wrench to the breakout cylinder to loosen the adapter. The breakout cylinder must be extended to loosen the adapter. The locking plate may need to be indexed

Rotation Circuit Page 8 Chapter 7 relative to the spindle adapter to allow for maximum torque to be applied to the “J” wrench.

Note: It may be necessary to increase the extend pressure for the breakout cylinder to loosen the adapter.

4. After the old adapter has been removed, thoroughly clean the API threads in the end of the spindle as well as on the new adapter.

5. When installing the new adapter, use LOCTITE primer #T747 and coat the threads with LOCTITE #680 (cpn #51948727) thread lock.

Install the adapter into the spindle and torque to 4500 lb-ft. (6100 Nm.) If the breakout cylinder is used for the retorque of the spindle adapter, it will be necessary to increase the pressure to the retract side of the cylinder to 2500 PSI. (175 Bar) to develop an adequate amount of torque.

Note: the breakout cylinder will deliver maximum torque when it is almost fully retracted.

6. Allow ample curing time for the LOCTITE #680. If the primer is used, the bond will be partially cured in 5 minutes and fully cured in 4 to 6 hours. If the primer is not used the partial cure time is extended to 30 minutes.

7. After the replacement of the spindle adapter is complete, reassemble the rod lock and front housing to the rotary head. Use care during the installation process to prevent damage to the rod lock seals. Reconnect all hydraulic lines.

Replacing the Chevron Air Packing

To replace the chevron air packing the following steps should be followed:

1. Remove the six (6) socket head 3/8” cap screws that secure the gooseneck to the air swivel.

2. Remove the ten (10) socket head M16 cap screws the secure the base of the air swivel housing to the rotary head.

3. The chevron packing can then be removed from the swivel housing.

4. Inspect the washpipe for wear and/or looseness on the threads at the end of the spindle.

5. The thread on the end of the spindle is a left-hand thread. If retightening is required, apply LOCTITE as described on page 14 or page 27 of this section of the manual. A special tool cpn 52291176 is required for this operation.

6. When the LOCTITE is applied, be sure to allow ample curing time to prevent loosening prematurely.

7. Install the new chevron packing as shown on the drawing on page 28 of this section.

8. Reinstall the swivel housing and gooseneck after grease has been applied to the new chevron packing.

9. Grease both grease fittings on the swivel before restarting the unit.

Replacing the spindle and/or spindle bearings

The drawing on page 11 can be used to identify various parts of the rotary head.

1. Remove the rod lock assembly and swivel housing as described previously in this section.

2. Unthread the washpipe from the end of the spindle. This will require the special tool cpn 52291176. NOTE: The threads in the washpipe are left-handed. Remove the seal plate directly under the washpipe.

3. Remove the twelve (12) M16 socket head capscrews that retain the hydraulic motor assembly to the bearing housing. Set the motor assembly aside being careful to keep the assembly clean.

Rotation Circuit Page 10 Chapter 7 4. Remove the twelve (12) M16 socket head capscrews that secure the top bearing plate. NOTE: The bearing plate is designed to provide the proper preload on the spindle bearings when tightened down.

5. At the bottom of the bearing housing, remove the eight- (8) M12 capscrews that retain the lower seal plate. Remove the seal plate from the housing.

6. Remove the spindle from the bearing housing. The top bearing cup is a slip fit into the housing.

7. If the bearings (cups and cones) are to be reused, carefully remove the cones from the spindle. These will have to be pressed onto the new spindle.

8. If the bearings are being replaced, the cone for the lower bearing will have to be pressed into place.

9. To reassemble the head, reverse the disassembly procedure. The washpipe and spindle adapter must be installed with LOCTITE.

Use LOCTITE primer #T747 and coat the threads with LOCTITE

#680 (cpn #51948727).

The torque specifications for the fasteners used in the rotary head are as follows:

M12 (grade 10.9) (lubricated threads)---55 lb-ft or 100 Nm.

M16 (grade 10.9) (lubricated threads)---138 lb-ft or 250 Nm.

Air System

Compressed air for operation of the down hole hammer as well as the dust collector and thread greasing system is provided by an HR2 compressor in the CM 760 and an HR2.5 in the CM 780. The CM 760 supplies 636 CFM at a maximum pressure of 350 PSI (24 Bar).

The CM 780 supplies 855 CFM at a maximum pressure of 350 PSI (24 Bar).

The compressor on each of these units is fitted with a normally closed inlet valve. A solenoid valve is used to “load” the compressor. This valve is energized only when the drill/tram mode switch is placed in the drill mode. This means that the compressor will remain at low pressure, 100-120 PSI (6.8-8.3 Bar) during warm up and during tramming.

Unloader Components

The inlet unloader includes the airflow regulation valve, the anti-rumble valve, pressure regulation and the blowdown valve within the unloader housing. The inlet valve is also equipped with a high-low pressure feature.

Startup

The unloader allows the engine to start with the compressor unloaded. This provides for easier starting, especially in cold weather. For the first minute of running, the compressor cannot be loaded. This gives the engine time to achieve stable operation and establish full oil flow through the engine and compressor. Allow several minute of idle run time before operating any system on the machine. This allows the engine to warm up before putting it under load. The engine can only be started with the drill/tram switch in the neutral or center position. The compressor is unloaded at this time.

During the warm up time period, the compressor receiver tank will slowly build up to 100 PSI (6.8 Bar) to 120 PSI (8.2 Bar). This normally takes about one minute. Once the receiver tank pressure has reached this level, the compressor can be loaded. If the pressure buildup takes too long, switching the drill/tram selector to

Air System Page 2 Chapter 8 Running Loaded

When the drill/tram selector switch is placed in the drill position, the receiver tank will build up to the maximum pressure setting of the inlet unloader. There is a low-high pressure switch on the left-hand joystick that allows the operator to select either setting. The low pressure setting is 200 PSI (13.7 Bar) and the high-pressure setting is 370 PSI (25.5 Bar). The compressor pressure will build up to the pressure setting that is selected. If the switch in the cab is set for high pressure, it can be switched at any time to the low setting.

Receiver tank pressure will then begin to drop to the low-pressure setting. This reduction of pressure may take a minute or more. It may in some cases, be desirable to collar the hole at the low setting to prevent excessive blowout of the top of the hole.

Shutting down

When the unit is to be shut down, it should be allowed to run for several minutes with the compressor in the low-pressure mode before stopping the engine. In an emergency the unit can be stopped with the compressor in any operating mode. In any shutdown situation, the compressor will blow down through the inlet valve. The noise during blow down is much less noticeable than with older unloader systems so be sure that the pressure has dropped to 0 PSI before disconnecting any lines on the air system. To be absolutely safe, open the manual blowdown on the top of the receiver tank.

Adjustment of the unloader

The illustration above shows the adjustments required to the unloader.

High Pressure Adjustment:

The high-pressure adjustment screw set the pressure at which the unit will unload on the hi-pressure setting. Run the unit loaded and when warm, turn the screw indicated clockwise to raise the pressure.

Set the warm unloaded pressure to 380 to 390 PSI (26-27 Bar). This setting will allow the unit to start unloading at 350 PSI (24 Bar). Lock the screw in position with the nut. New units often need readjustment after the first hours of running,

Air System Page 4 Chapter 8 Low Pressure Adjustment:

After the high pressure is set, the low-pressure screw will set the low pressure setting. Place the hi/low switch in the cab to the low-pressure position. Turn the screw clockwise to raise the low low-pressure setting. The minimum pressure available is 200 PSI (13 Bar). Lock the screw in position with the nut.

NOTE: Always set the high pressure prior to setting the low pressure.

Unload Stability Adjustment:

The Unload Stability Adjustment Screw adjusts the leak rate into the unloader to compensate for different tolerances of the unloader internal parts. This adjustment can solve several annoying problems, such as too much discharge pressure oscillation at idle/unload. A small amount of oscillation is acceptable, for example: cycling between 370 and 390 PSI (25-27 Bar) over a period of about 30 seconds. A good starting point for adjusting this screw is 1.25”

(31mm.) between the screw head and the top of the nut. This is the maximum leakage rate position and screwing it out any further will not have any additional effect. Turn the screw in to reduce unloaded cycling. Another potential problem is if the start/unload pressure is less than 100 PSI (6.8 Bar) (unload/run switch is set to the unload position). If this pressure is to low, the unloader will not respond quickly when the unload/switch is switched to run. Screw the stability screw in to raise the start/unload pressure to 100 PSI (6.8 Bar) to obtain proper response. Use this adjustment screw carefully. If the screw is turned in to far, then pressure will build up in the receiver tank during normal unloading when the switch is set to run. This can cause pressure in the receiver tank to climb high enough to pop the safety relief valve. Always check to see that the unloaded pressure is stable during normal unloading after adjusting this screw. Lock the screw in position with the nut after adjustment.

The above picture shows the major components of the unloader valve. Refer to previous 2 pages for adjustment procedures.

Air System Page 6 Chapter 8 Inlet valve removed from compressor

Operation of inlet valve:

As stated previously in this chapter, the inlet valve is a normally closed valve. The inlet valve consists of two main components. First is the check valve that is spring loaded to the closed position.

Whenever the unit is “making air”, the inlet valve is pulled open by the airflow. It the airflow stops (for example the engine runs out of fuel), the check valve will close and prevent oil from entering the air cleaner. Second, the inlet valve sleeve that opens and closes to regulate or shut off inlet airflow to the compressor. Control air pressure from the regulation system opens the sleeve valve (see the diagram on the page 12). In this diagram the green represents the pressure signal from the receiver tank, the blue represents control pressure and the light green is connected to atmosphere (airend inlet). When the control pressure is less than 50 PSI (3.4 Bar), the inlet valve is closed (unloaded). From 50 PSI (3.4 Bar) to 120 PSI (8.2 Bar), the inlet sleeve regulates to full open. Above 120 (8.2 Bar),

Start/Run Solenoid

High/low Solenoid

the inlet valve is fully open. Control pressure opens the inlet valve in this system, whereas in most systems, the inlet valve is closed by control pressure. When it is closed there is no control pressure to lift the inlet valve and the compressor does not “make air”. When the engine is running the compressor will slowly build pressure up to about 100 PSI (7 Bar) even when the start/run solenoid is off and the inlet sleeve valve is closed. This brings the system pressure up so the unit is ready to run. When the start/run solenoid is energized, receiver pressure is directed to the air chamber under the regulator spool (bottom of the three ports on the side of the unloader housing).

The bottom of this spool has clearance to allow receiver pressure to leak by and become control pressure (the middle of the three ports on the unloader housing). This control pressure opens the inlet valve.

When the inlet pressure reaches 200 PSI (13.7 Bar) (high/low valve in the low pressure position), there is enough force on the bottom of the regulator spool to lift it up against the spring to open the vent to the inlet (top of the three ports on the unloader housing). This vents the control pressure back to zero, causing the inlet sleeve valve to fall and close the inlet. When the high/low valve is in the high-pressure position, the top red spool is pushed down so that it compresses the spring. In this case, the lower red spool valve will not lift and vent the control pressure until the compressor discharge pressure reaches 350 PSI (24 Bar). In either case, high discharge pressure or low discharge pressure, the control pressure opens the inlet valve from 50 PSI (3.4 Bar) to 120 PSI (8.2 Bar). The high/low solenoid is a normally off (not energized). This means that pressure on top of the red spool is vented to inlet and cannot build up to compress the spring. When the high/low solenoid is energized (closed), pressure can build up to compress the spring. The unloader assembly also includes an anti-rumble valve. The diagram on page 14 depicts a cross section of this part of the assembly. Whenever the control pressure (middle port) drops below 50 PSI (3.4 Bar) (inlet valve closed), this valve opens and lets a small amount of air enter the airend to keep the rotors from “rumbling”. Air will also vent into the inlet (past the stability screw) to keep the separator tank pressure from building up and popping the safety valve. When the engine is shut down, this valve opens up automatically to blow down the separator tank. This “blowdown” air goes into the airend inlet pipe and comes out of the air filter.

Air System Page 8 Chapter 8 It is important to note that receiver pressure that is directed to the air manifold on the unloader housing is mostly dry air. However, a small amount of wet air (oil mist) is directed through a .030 orifice to lubricate the internal components of the inlet valve.

The drawing above shows the inlet valve open and the compressor delivering air to the receiver tank. The upper red spool is held down by receiver pressure.

Air System Page 10 Chapter 8 When the unit is to be shut down, the high/low switch in the cab should be placed in the low position and the unit allowed to run for several minutes prior to stopping the engine. When the engine is stopped, the inlet valve is closed and air pressure in the compressor unit closes the red check ball. This prevents air and oil from backing up into the inlet filter and into the control circuits. Pressure from the air receiver tank bleeds through the anti-rumble/blow down valve at this time. Always be sure that the pressure in the receiver tank is completely evacuated before opening any line on the unit.

Air System Page 12 Chapter 8 The HR2 & HR2.5 use synthetic fluid in its operating cycle. The unit is shipped with Ingersoll-Rand XHP505 fluid from the factory. Do not use any other fluid that may not be compatible with the recommended fluid.

PRINCIPAL OF OPERATION:

Up to this point we have discussed the control principals of the HR2 &

HR2.5 system. Air is allowed to enter the primary or low-pressure stage of the compressor through the open inlet sleeve valve. The air enters because the rotating compressor rotors create a vacuum at the inlet end of the unit. The primary stage handles a large volume of incoming air. The incoming air is trapped by the rotors and carried forward between the rotors and the compressor housing to the outlet of the primary unit. At this point the air from the primary rotors is

HR2.5 system. Air is allowed to enter the primary or low-pressure stage of the compressor through the open inlet sleeve valve. The air enters because the rotating compressor rotors create a vacuum at the inlet end of the unit. The primary stage handles a large volume of incoming air. The incoming air is trapped by the rotors and carried forward between the rotors and the compressor housing to the outlet of the primary unit. At this point the air from the primary rotors is