National Crane 600H, Руководство по обслуживанию

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NATIONAL CRANE
08-19-2022 Control # 092-13
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600H SERVICE MANUAL INTRODUCTION
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Wire rope shall be taken out of service when any of the
following conditions exist:
• Six randomly distributed broken wires in one rope lay or
three broken wires in one strand in one lay. The rope is
unsafe for further use if there are either three broken
wires in one strand (Breaks 2, 3, 4) or a total of six
broken wires in all strands in any one lay.
• In rotation resistant ropes: two randomly distributed
broken wires in six rope diameters or four randomly
distributed broken wires in 30 rope diameters
• Wear of one-third the original diameter of outside
individual wires. Worn rope, usually indicated by flat
spots on the outer wires is unsafe for further use when
less than two-thirds the thickness of the outer wire
remains.
• Necking down of the rope indicates core failure.
• Kinking, crushing, bird caging, or any other damage
resulting in distortion of the rope structure.
• Evidence of heat damage.
• Reductions from nominal diameter of more than 5%.
• One outer wire broken at its point of contact with the core
of the rope which has worked its way out of, and
protrudes or loops out from the rope structure.
Care of Wire Rope
Handle wire rope with care to prevent damage to the
individual wires which affect the overall strength and
performance of the rope. Do not allow the formation of kinks,
because this displaces the strands of wire from their original
position and relation to each other causing severe bending
and unequal tensions in the strands. This distortion and wire
displacement cannot be corrected even under high tension
and a permanent weak point remains in the rope. Displaced
or raised wires indicate a previous kink, but does not show
the damaged condition of the inner rope wires.
Never pull wire rope over a non-rotating support such as a
spindle bar, a pin, or an inoperative sheave. This practice
causes severe abrasion to the outer strand wires. A properly
operating sheave or snatch block is essential to safety and
long service life of the rope.
Do not use worn sheaves or sheaves with flat grooves
because they do not provide sufficient support to prevent the
distortion and flattening of the rope. Sheaves with nicked or
broken flanges can cut or otherwise damage the rope.
An even distribution of rope coils over the hoist drum is
essential to smooth operation. This prevents the rope from
cutting down through or crushing other coils on the drum
resulting in damage to and difficulty in unwinding the rope.
Boom Extension and Retraction Cables
Periodic Inspection
It is recommended that a weekly inspection of all boom
extension and retraction cables be performed using the
following guidelines. The inspection shall cover all visible
areas of the extension and retraction cables of an assembled
boom. Note that extending and/or retracting the boom may
be required to access visual inspection holes.
The inspection shall cover the entire length of the extension
and retraction cables of a disassembled boom prior to
reassembly.This inspection should be used to monitor
progressive degradation and to discover severe damages
necessitating wire rope replacement or equipment repair.
Inspection criteria are as follows:
• reduction of rope diameter below nominal diameter.
• severely corroded or broken wires at end connections.
• severely corroded, cracked, bent, worn, or improperly
applied end connections.
• deterioration in areas such as:
- sections in contact with saddles, equalizer sheaves,
or other sheaves where rope travel is limited.
- sections of wire rope at or near terminal ends where
corroded or broken wires may protrude.
- sections of wire rope in contact with stationary
surfaces where abrasion or chafing may take place
as a result of equipment vibration.
• damaged or wobbly boom extension and retraction
sheaves which can cause rapid deterioration of wire
rope.
• unusual cable sag/stretch. Be sure cables used in sets
all have an equal tension applied. Repeated need for
adjustment of an individual cable is evidence of cable
stretch and indicates the need for a more thorough
inspection to determine and correct the cause.
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