Recommended Periodic Checks; Door Stop Spring; Shifting Shaft; Backing Pin - Farr HD8625 Technical Manual

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ainTenance
F.

RECOMMENDED PERIODIC CHECKS

1.

Door Stop Spring

The spring inside the actuator cylinder must be of sufficient strength to enable the door latch mechanism to snap closed properly.
Door stop spring fatigue will result in sluggish latch operation. Replace the latch spring inside the cylinder when this occurs.
2.

Shifting Shaft

The shifting yoke is secured to the shifting shaft by one hex jam nut and one locknut on the bottom of the yoke. Check these nuts
after each job. Do this by removing the clutch inspection plate and ensuring a snug fit prior to lubrication.
3.

Backing Pin

Perform a visual inspection of the backing pin after each job. Replace the pin if stress cracks or excessive wear is found, or if the
pin appears bent.
4.

Torque Gauge Assembly

Periodic calibration of the torque gauge is recommended to assure accurate torque readings. When having the torque gauge ser-
viced and calibrated, it is critical to note the arm length of the tong, as indicated on page 1.3.
G.

OVERHAUL PROCEDURES - DISASSEMBLY

Once the tong has been removed from the backup it may be overhauled using the disassembly instructions specified in the following
procedure. Access to the gear train is possible by removal of the top plate of the tong.
ALL MAINTENANCE AND OVERHAUL SHOULD BE PERFORMED FROM THE TOP. THE BOTTOM
PLATE OF THE TONG IS TYPICALLY WELDED TO THE SIDE BODY AND CANNOT BE REMOVED.
REPLACEMENT FASTENERS (BOLTS, NUTS, CAP SCREWS, MACHINE SCREWS, ETC.) USED
DURING MAINTENANCE OR OVERHAUL MUST BE GRADE 8 OR EQUIVALENT.
FASTENERS USED FOR MAINTENANCE OR OVERHAUL OF LOAD-BEARING COMPONENTS
(CHAIN SLINGS, RIGID SLINGS, LEGS) MUST BE TIGHTENED TO THE PROPER TORQUE
SEPARATION OF TONG FROM BACKUP
1. Suspend tong assembly with crane. Construct a support structure that will support the weight of the backup. Lower the tong on to the
constructed support.
2. Support the rigid sling with a crane. Remove the rigid sling assembly by disconnecting the leveling devices from the hanger brackets,
and use the crane to lift the sling away from the tong. Store in a protected area.
3. Remove the two rigid sling hanger brackets.
4. Disconnect the three hydraulic connections from the motor. Undo the restraints securing the inlet and outlet lines connections to their
supports, and lift the hydraulic valve section away from the tong. Remove the inlet and outlet support pieces.
5. Remove top brake band assembly (leave adjustment lug weldments in place for now).
6. Remove the tong door stop cylinder.
7. Remove door assembly by removing the door roller shaft. Support door assembly as the roller shaft is removed. Remove the nut from
the top of the roller shaft, and use a soft alloy material (e.g. brass rod, etc.) to lightly tap the shaft down through the support roller
assembly until it comes free at the bottom. Use caution that the threads on the ends of the support roller shafts are not damaged. Do
not lose the door shoulder bushings.
8. Remove the hitch pin securing the torque gauge holder to the torque gauge mount weldment, and remove the mount.
9. Remove the four hex socket head cap screws securing the motor and the torque gauge mount weldment. Remove the torque gauge
mount weldment, then lift the motor up and away from the motor mount. Inspect the motor gear, located at the bottom of the motor
shaft, for gear clashing or tooth damage. Also, ensure that the motor gear is securely attached to the motor shaft.
10. Remove the cotter pin and clevis pin connecting the shifter handle to the shifter shaft (it is not necessary to disconnect the handle
from the pivot lug weldment).
11. Unbolt the pivot lug weldment from the top plate, and remove the pivot lug and handle assembly.
12. Remove the four hex socket head cap screws securing the motor mount to the top plate. Use care not to dislodge and lose the two
positioning dowels.
13. Remove the snap ring securing the drive gear to the top of the clutch shaft. Carefully remove the drive gear from the clutch shaft.
hD8625 8- " 35K T
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