UNA COSA QUE PIENSA COMO LÍMITE DE LA DUDA
2. Escepticismo cartesiano
The four outrigger stabilizer cylinders each have a hollow rod for internal porting (Figure 2-47). Each cylinder has a 165.1 mm (6.5 inch) diameter bore. A port block is welded to the rod of each cylinder and a pilot operated check valve is threaded into each port block.
The retracted length of the cylinder from the end of the barrel to the center of the rod’s port block rod bushing is 1416 mm (55.75 inches). The extended length of the cylinder from the end of the barrel to the center of the rod’s port block rod bushing is 2235.2 mm (88 inches). Its stroke is 819.2 mm (32.25 inches).
A wiper ring prevents foreign material from entering the cylinder. O-rings and other seals prevent internal and external leakage.
The cylinder weighs approximately 100 kg (220.4 pounds).
Maintenance
Disassembly
NOTE: Any maintenance requiring disassembly of the cylinders should include replacement of all seals and rings. A seal kit will supply the required items.
1. Remove the check valve from the port block.
2. Loosen the head’s setscrew. Using a chain wrench, unscrew the head from the barrel.
3. Remove the rod and attached parts from the barrel.
NOTE: Cover the barrel opening to avoid contamination.
4. Remove a hydrolock seal from the outside of the piston to gain access to the set screw.
NOTE: Arranging discarded seals and rings in the order of disassembly will aid in installation of new seals and rings. Pay attention to how each seal and ring is installed to avoid installing replacement seals and rings improperly.
5. Remove the piston’s set screw. Unscrew the piston from the rod.
6. Remove the other hydrolock seal from the outside of the piston.
7. Remove the o-ring and the two backup rings from the inside of the piston.
8. Remove the spacer from the rod.
9. Remove the head from the rod.
10. Remove the o-ring and the backup ring from the outside of the head and the two wear rings, buffer seal, rod seal and wiper ring from the inside of the head.
Inspection
1. Clean all parts with solvent and dry with compressed air.
Inspect all parts for serviceability.
2. Inspect the barrel carefully for scoring. If barrel is scored, it must be repaired or replaced.
3. Check piston for damage. If piston is damaged, determine if it can be repaired or must be replaced.
4. Inspect rod for straightness. Determine if it can be straightened or must be replaced. Verify internal passages and ports are clean and undamaged.
5. Stone out minor blemishes and polish with a fine crocus cloth.
6. Clean with solvent and dry with compressed air any parts that have been stoned and polished.
DANGER
Do not use air pressure to remove the rod. Use only a source of controlled hydraulic oil pressure if the rod is hard to remove.
CAUTION
Exercise extreme care when handling or setting down the rod. Damage to the rod surface may cause unnecessary maintenance and expense.
CAUTION
When removing seals and rings, avoid scratching the grooved and gland surfaces.
CAUTION
Before installing new seals and rings, clean all surfaces and carefully remove burrs and nicks. Parts displaying excessive wear or damage should be replaced.
FIGURE 2-47
1
2
3 4
5
6 9
10
12
13 14
15 16
17 18
19
7281 21, 22
7, 8
20 19
Item Description
1 Barrel
2 Rod
3 Head
4 Piston
5 Spacer
6 Check Valve
7 Setscrew
8 Insert
9 Plug
10 Plug
Item Description
12 Rod Seal
13 Buffer Seal
14 Wear Ring
15 O-ring
16 Backup Ring
17 Seal
18 O-ring
19 Backup Ring
20 Setscrew
21 Insert
2
Assembly
NOTE: Lubricate seals and rings with clean hydraulic oil.
NOTE: Make sure the gaps of the two wear rings are 180 degrees apart.
1. Install the replacement wear rings, buffer seal, rod seal and wiper ring in the inside of the head (Figure 2-48).
Make sure the buffer seal’s step is away from the wear rings. Make sure the deep Z rod seal rim groove is closer to the wear rings.
2. Install the replacement o-ring and the backup ring on the outside of the head.
3. Install the replacement o-ring and backup rings in the inside of the piston.
4. Install one replacement hydrolock seal on the outside of the piston (Figure 2-49). Leave the other hydrolock seal off for now so there is still access to the piston’s set screw hole.
5. Lubricate the rod with clean hydraulic oil.
6. Slide the head, larger OD end first, onto the rod.
7. Slide the spacer onto the rod.
8. Screw the piston onto the rod until it can go no farther.
Hold the piston in place with the set screw.
9. Install the other replacement hydrolock seal on the outside of the piston over the set screw. Make sure the
“vees” on the two hydrolock seals point at each other.
10. Lubricate all parts freely with clean hydraulic oil.
11. Remove the cover from the barrel. Insert the rod and attached parts into the barrel with a slight twisting motion.
12. Clean all oil from the threads of the head. Coat the threads with an anti-seize compound (Never-Seez paste lubricant or similar lubricant). Using a chain wrench, screw the head into place on the barrel so its larger OD end is flush with the end of the barrel.
13. Check the inside of the port block for any sharp edges or burrs and remove as necessary with emery cloth.
14. Install new o-rings onto the check valve.
15. Lubricate the check valve and o-rings with clean hydraulic oil.
NOTE: The check valve should turn by hand until compression of the o-rings begins.
16. Carefully install the check valve into the port block until fully seated.
17. Pressurize and cycle the cylinder with hydraulic oil pressure. Test the cylinder at 3620 kPa (5250 psi).
Check for proper operation and any leakage. Make repairs as needed.
CAUTION
When installing new seals and rings, avoid stretching seals or scratching the grooved or gland surfaces. Make sure parts are clean before and during assembly. Make sure seals and rings are installed in the proper order.
Wiper Ring
Exercise extreme care when handling the rod. Damage to the rod surface may cause unnecessary maintenance and expense. Also, take care to avoid damaging grooved or gland surfaces or rings or seals during rod insertion.
CAUTION
Do not damage the o-rings during installation of the check valve. If the check valve turns freely then gets hard to turn, then easy to turn, remove the check valve and check the o-rings. They have probably been damaged by a sharp edge of a port.
CAUTION
Do not use air pressure to cycle or pressurize the cylinder.