Page 9
(4) Check anchor end of chain at side of hoist frame for
damage to last link, also connecting link on roller chain hoists.
Replace damaged parts.
(5) Check connection of chain to lower block on 1/4, 3/8
and 1/2 ton hoists. Replace parts showing evidence of
damage, twisting or elongation.
(6) Check connection of chain to anchor on side of
suspension bracket on double reeved, 3/4 and 1 ton hoists.
Replace parts showing evidence of damage, twisting or
elongation.
(7) Lubricate load chain if required. See paragraph 4-4,
Section IV.
b. Inspect Lower Block.
(1) Check for bent or distorted hook. If hook is opened beyond
the dimension given in Figure 5-3, it must be replaced. Also
check to see that hook swivels, and is free to pivot on roller
chain models. Lubricate these points if necessary.
(2) On 3/4 and 1 ton hoists, check sprocket and bearings in
lower block for freedom of movement and signs of damage.
Lubricate if necessary. Replace damaged parts.
Figure 5-3. Upper Lower Hook Openings.
(Shown with latch removed for clarity.)
Hoist Rated Load
(tons)
Hook Throat Opening
Normal
Opening
Replace Hook if Opening
is Greater Than
Std.
S.R.
1/4
—
1-1/8"
1-9/32"
1/2
3/8
1-1/8"
1-9/32"
1
3/4
1-1/4"
1-7/16"
12394
c. Inspect Upper Suspension.
(1) On hook suspended models, check for bent or distorted
hook. If hook is opened beyond the dimension given in Figure
5-3, it must be replaced. Also check to see that hook swivels.
Lubricate if necessary.
(2) On push trolley suspended models, check condition of
trolley parts and lug bracket. Replace bracket or any trolley
parts which are damaged or cracked.
(3) Check hook latch. Replace damaged or bent latch or
broken spring.
d. Check Brake Operation.
(1) With air turned on and with rated load attached to lower
hook, operate hoist to raise load, applying pressure to pull
cord handle or throttle control lever. If load drifts down before
the motor starts to actuate, the brake is out of adjustment.
(2) To adjust brake, insert hex key through hole in brake
cover. Turn screw counterclockwise to tighten brake or clockwise
to loosen brake (see Figure 7-15).
5-3. ANNUAL INSPECTION. Hoist must be disconnected from
air service and removed from overhead suspension. Hoists
subjected to severe service or to adverse environments
should be examined weekly or as conditions warrant.
a. Hoist should be partially disassembled as necessary to
inspect hoist parts noted in paragraphs b. through h. below.
Refer to Section VII for disassembly and reassembly steps as
noted.
b. Inspect Brake. Remove brake housing cover and brake
shoes as outlined in paragraph 7-2.c. Check brake shoe linings
and brake wheel for wear and scoring. Replace badly worn or
scored parts. Check condition of brake cam and spring. Replace
any damaged parts.
c. Inspect Internal Load Gears. Remove gear plate and
intermediate gears as outlined in paragraph 7-2.f. Check
condition of gear teeth on internal gear, intermediate gears,
and motor shaft pinion. Replace worn or damaged parts.
d. Inspect Chain Sprocket and Bearings. Remove sprocket
and internal gear as a unit, paragraph 7-2.f. Check condition of
teeth or pockets on chain sprocket and inspect ball bearing
assemblies. Replace worn or damaged parts.
e. Inspect Throttle Valve Shifter. Remove valve shifter and
control shaft (paragraph 7-2.c.) and shifter pin (paragraph 7-
2.d.). Check condition of shifter, pin and shaft bearings. Replace
worn or damaged parts.
f. Inspect Throttle Valve Housing. Remove throttle housing
assembly (paragraph 7-2.d.) and disassemble it as outlined.
Check condition of throttle valve, valve bushing (in housing)
and “0” rings on valves. Replace worn or damaged parts.
g. Inspect Air Motor. Remove air motor assembly from hoist
(paragraph 7-2.e.). Check motor for condition of bearings,
possible rotor rubbing on body or end plates, blade freedom in
rotor slots, shaft and gear. If motor appears to be in good
condition, do not service other than lubricating well with light
oil.
h. Reassemble and Test Hoist. Reassemble hoist as outlined
in Section VII, paragraph 7-4. After reassembly, test hoist in
accordance with paragraph 7-5.
Hooks, upper or lower, damaged from chemicals,
deformation or cracks or having more than 15 percent
in excess of normal throat opening or more than 10
degrees twist from the plane of the unbent hook, or
opened, allowing the hook latch to bypass hook tip
must be replaced.
Any hook that is twisted or has excessive throat
opening indicates abuse or overloading of the hoist.
Other load bearing components of the hoist should be
inspected for damage. (See Section V, paragraph 5-3
below.)
WARNING
(3) Check hook latches. Replace damaged or bent latches
or broken springs.
