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14
WARNING
Do not operate a hoist having unusual
vibrations, sounds, or with anything
wrong or apparently wrong. Danger may
be present that the hoist operator
cannot see. Determine and correct the
cause of unusual conditions and make
certain hoist can be operated safely.
5-2. INSPECTION OF LOWER BLOCK.
a) Check lubrication of all parts. Also lubricate
the shank of the hook that passes through
the crosshead. If the thrust bearing is
removed, apply MPG grease (Section IV,
Para. 4-7).
b) Check each sheave to insure rope groove
is smooth and free from burrs, or other
surface defects.
c) Check each sheave for freedom of rotation;
replace bearings if defective.
d) Make certain that the spring pin holding the
hook nut to the hook is securely in position.
e) If hook is equipped with a hook latch or
rotational lock, check to determine that they
are in good operating condition.
f) Check throat opening of the hook. (Refer to
Figure 5-2.) It is recommended that upon
receipt of the hoist, a measurement be
made and recorded of the hook throat
opening. OSHA regulations require that the
hook be replaced if the throat opening
exceeds 15 percent of the original opening,
or if the hook is twisted more than 10
degrees from the unbent plane. We
suggest that a gage block properly
identified to the hoist, similar to the one
shown in Figure 5-2, be made for each
hook for use in these measurements.
FIGURE 5-2 Gage Block.
g) Hooks showing signs of cracks must be
replaced. Hooks should be inspected at
least once per year using dye penetrants,
magnetic particle, or other suitable non-
destructive test methods.
h) Check wear of the hook, especially at the
saddle and replace if worn more than 10%
of original dimensions.
5-3. INSPECTION OF UPPER BLOCK.
a) Check upper block sheaves (when hoist is
so equipped) for wear, damage and
freedom of rotation.
If sheaves do not rotate freely, disassemble
block and inspect bearings. Replace worn
or damaged bearings, washers, pins, or
sheaves.
b) Make certain that all sheaves, bearing and
hanger pins are free of foreign material.
Bearings without grease fittings are
lubricated for the life of the bearing and
require no further lubrication.
c) Make certain that the rope retention bolts
are not bent, loose or otherwise distorted;
bolts must have close clearance to sheave
flange to keep rope in sheave grooves.
5-4. INSPECTION OF ELECTRICAL CONTROLS.
Arrangement of electrical control equipment varies
with the type of control, physical space and the
optional control features ordered with the hoist.
Note the location in the electrical enclosure of the
control circuit fuse, transformer, limit stop switches
and the hoist contactors. Trolley contactors and
optional hoist and trolley fuses are also located in
this enclosure.
Use wiring diagrams furnished with hoist to
determine electrical components on your hoist; then
determine component location and identity on your
hoist.
WARNING
Be certain that main power switch is
locked in open position (OFF) before
opening hinged control enclosure cover
mounted to the counterweight.
a) Open hinged control panel enclosure cover
mounted to the counterweight and inspect
wiring and terminals. Terminals should be