SWING NBT30H-2 SERVICE MANUAL
6-8 03-20-2019 Control # 613-06
8. Bolt the brake end plate (18) to the brake housing (1)
with the capscrews (19). Alternately tighten the
capscrews one turn at a time until the cover is tight
against the brake housing.
NOTE: This keeps the pressure on the end plate
distributed evenly. Torque the capscrews to
recommended values, refer to Fasteners and
Torque Values, page 1-12.
SWING BEARING
Description
The swing bearing is an anti-friction roller bearing that mates
the turret to the frame. The bearing inner race is bolted to the
turret and the outer race is bolted to the frame. The outer
race contains four grease fittings for lubrication of the
bearing. The inner race incorporates gear teeth that mesh
with the pinion gear of the swing gearbox to provide rotation.
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.
Therefore, proper care of the bearing and periodic
maintenance of the turret-to-bearing attachment 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.
Torque the capscrews to recommended values, refer to
Fasteners and Torque Values, page 1-12.
NOTE: Zinc flake coated bearing bolt heads are stamped
with the suffix "ZF" as a visual identifier.
When a high strength bolt is removed, or un-torqued, the bolt
must be replaced with a new bolt of the same classification.
Before performing the following procedure refer to Torque
Wrenches, page 1-12 on the proper use of a torque wrench.
Swing Bearing Bolts
The inner race of the bearing is secured to the turret by 30,
one inch, Grade 8 bolts (Figure 6-6). The outer race of the
bearing is secured to the frame by 30, one inch, Grade 8
bolts (Figure 6-6).
WARNING
Crushing Hazard!
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.
To Next Page
Loading...
Need help?
General
