National Crane 600H, Руководство по обслуживанию

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NATIONAL CRANE
08-19-2022 Control # 092-13
6-7
600H SERVICE MANUAL SWING
6
6. Now rotate the crane in the opposite direction until the
rotation stop system centers the control lever.
7. Make another mark on the crane frame aligned with the
center of the lift cylinder.
8. If the rotation stop system is properly adjusted, the
distance should be the same from the first mark made to
the second mark, as it is from the first mark to the third
mark.
9. If not, loosen the nut on either side of the spacer on the
flag rod actuator rod and adjust the position of the
spacer. Tighten the two nuts and repeat steps 3 through
7 above until proper adjustment is achieved.
MAINTENANCE
General
The swing bearing is the most critical maintenance point of
the crane. It is here, at the centerline of rotation, that
stresses of loads are concentrated. In addition, the bearing
provides the only attachment between the turret and frame.
Theref ore, prop er ca re of th e be aring an d pe riodic
maintenance of the turret-to-bearing attach bolts IS A MUST
to ensure safe and efficient operation.
TORQUING SWING BEARING BOLTS
General
Maintaining proper torque value for bolts is extremely
important for structural strength, performance, and reliability
of the crane. Variations in torque can cause distortion,
binding, or complete separation of the turret from the frame.
Proper identification of bolt grade is important. When marked
as a high strength bolt (grade 8), the serviceman must be
aware of bolt classifications and that he is installing a high
strength heat-treated tempered component and the bolt
must be installed according to specifications. Special
attention should be given to the existence of lubricant and
plating that will cause variation from dry torque values. When
a high strength bolt is removed, or un-torqued, the bolt must
be replaced with a new bolt of the same classification.
Torque the capscrews to recommended values, refer to
Fasteners and Torque Values , page 1-7.
NOTE: Zinc flake coated bearing bolt heads are stamped
with the suffix “ZF” as a visual identifier.
KNOW YOUR TORQUE WRENCH! Flexible beam type
wrenches, even though they might have a pre-set feature,
must be pulled at right angle and the force must be applied at
the center of the handle. Force value readings must be made
while the tool is in motion. Rigid handle type, with torque
limiting devices that can be pre-set to required values,
eliminate dial readings and provide more reliable, less
variable readings.
NOTE: If multipliers and/or special tools are used to reach
hard to get at areas, ensure torque readings are
accurate.
Torque wrenches are precision instruments and must be
handled with care. To ensure accuracy, calibrations must be
made on a scheduled basis. Whenever there is a possibility
that a torque wrench may have been either overstressed or
damaged, it should immediately be removed from service
until re-calibrated. When using a torque wrench, any erratic
or jerking motion can result in the application of excessive or
improper torque. ALWAYS use a slow, even movement and
STOP when the predetermined value has been reached.
If it is reported by the crane operator or suspected that the
crane has been overloaded beyond the capacities specified
above the bold line on the cranes’ capacity chart, then all
swing bearing bolts must be inspected for looseness and
re-torqued to specifications.
Torque the swing bearing bolts according to the procedures
outlined in this section.
When using step wrenches, calculated wrench settings are
valid only when the following conditions are met.
1. Torque wrenches must be those specified and forces
must be applied at the handle grip. The use of handle
extensions will change applied torque to the bolt.
2. All handles must be parallel to the step wrench during
final tightening. Multiplier reaction bars may be
misaligned no more than 30 degrees without causing
serious error in torque.
3. Multiplier bar handles must be propped or supported
within the outer 1/4 of the handle length, or serious
under or over tightening will occur.
Swing Bearing Bolts
The inner race of the bearing is secured to the turret by 26, 1-
8 UNCX2.25, Grade 8 bolts (Figure 6-9). The outer race of
DANGER
It is mandatory that swing bearing and T-box attaching
bolts be inspected and re-torqued after the first 300 hours
of crane operation and every 500 hours thereafter. The
bolts may loosen and cause the crane to separate from
the carrier which will result in damage to the crane and
possible injury or death to personnel.
CAUTION
Repeated re-torquing may cause bolts to stretch. If bolts
keep working loose, they must be replaced with new bolts
of the proper grade and size.
!
REFERENCE ONLY