Farr 80-0420-16, Technical Manual

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KT5500 5-
1
/
2
” T
ong
& CLInCHER® B
aCKup
S
ECTIon
C
onTEnTS
3.9
T
ECHnICaL
M
anuaL
M
aInTEnanCE
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/
backup assembly onto the constructed support until all weight is removed from front leg suspension springs.
2. Disconnect all hydraulic lines from the backup.
3. Remove the nylock nut and bolt sets from the bottom of the front legs, and slide the lower spring caps and front leg coil springs
off each leg. Note that the top spring caps will remain within the backup body assembly.
4. Disconnect the two rear backup support springs connecting the backup to the rear leg (not applicable for low-profile compres-
sion-style backup).
5. Remove the load cell assembly.
6. Lift tong and legs up and away from the backup, and set tong onto a flat work surface that will support the weight of the tong,
and allow access to the bottom plate- ensure that the legs do not have any weight on them.
REMOVAL OF LEG ASSEMBLIES.
7. Remove the rear leg assembly by removing two 1-1/4” x 8” hex bolt and nut sets and two 7/8” x 9” hex bolt and nut sets.
8. Remove the front leg assemblies by removing the 1/2” x 3-3/4” bolts and nut set on each leg, and slide leg tubes out of leg
mount weldments.
REMOVAL OF TOP PLATE
9. Remove the rigid sling assembly by disconnecting the leveling devices from the hanger brackets.
10. Remove the two rigid sling hanger brackets.
11. Disconnect the three hydraulic connections from the motor. Undo the restraints securing the inlet and outlet lines from their
supports, and lift the hydraulic valve section away from the tong. Remove the inlet and outlet support pieces.
12. Remove top brake band assembly (leave adjustment lug weldments in place for now).
13. Remove the tong door stop cylinder.
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 prop-
erly, and to hold the door in the open position when opened. Door stop spring fatigue will result in sluggish latch operation.
Replace the latch spring inside the cylinder when this occurs.
2. 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
either pin is bent.
3. Shifting Shaft
The shifting yoke is secured to the shifting shaft by a locknut on the bottom of the yoke. Check locking nuts after each job. Do
this by removing the clutch inspection plate and ensuring a snug fit prior to lubrication.
4. Torque Gauge Assembly
Periodic calibration of the torque gauge is recommended to assure accurate torque readings. When having the torque gauge
serviced and calibrated, it is critical to note the arm length of the tong, as indicated in the “Specifications” section. Farr recom-
mends that the torque gauge assembly be calibrated yearly. Periodically check to ensure the load cell is filled with oil (see
Section 6).
G. OVERHAUL PROCEDURES
The tong may be overhauled following the disassembly instructions in the following procedure. Access to the gear train is possible
by removing 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.