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Inspection and Maintenance
ARO recognizes the need for periodic inspection of hoist components as an important step in preventive
maintenance. The type of application for a hoist varies so greatly, it is impractical to recommend an exact time-table
for inspection of the hoist, Where hoist is subjected to continuous operation with capacity loads, it is recommended
the unit be inspected daily to weekly. If the application is less demanding, the unit should be inspected weekly to
monthly. In general, the frequency of inspection should be determined by the severity of the application.
The user of a hoist should be guided by any existing federal, state or local regulations governing the use, testing or
inspection of the hoist.
The following points and areas are recommended for inspection:
Load Chain and Anchors
1. Visually check for nicked, gouged, twisted, bent, corroded, rusted, worn or broken links. Check ends of chain
where chain is anchored to hoist frame and where chain is fastened to lower hook. Check anchors and pins.
2. Check chain elongation with a vernier caliper as shown in
INFERRED that a chain is safe prior to the occurrence of elongation of the chain. It is inferred ONLY, that when
said elongation is evident, the chain must be replaced. Other factors, such as those mentioned as a visual check,
may render chain unsafe long before replacement due to elongation is necessary.
Note: New chain should never be used on a worn pocketwheel. Replace chain and pocketwheel as a pair, chain
should also be replaced when replacing brake shoes.
Gears, Bearings and Sprocket
1. Check condition of teeth on gears and motor shaft pinion.
2. Check condition of sprocket teeth or pockets of pocketwheel.
3. Check condition of bearings.
4. Replace any worn or damaged parts.
Figure 4. MHP3411
VERNIER CALIPER
(16 mm)
.625 PITCH
4.755 NEW CHAIN
(120.7 mm)
IF VISUAL CHECK REVEALS NO DEFECTS, PROCEED AS FOLLOWS:
LAY USED CHAIN ON FLAT SURFACE AND MEASURE OVER EIGHT (8) ROLLS, WHILE
CHAIN IS PULLED TAUT, AS SHOWN. MEASUREMENT SHOULD BE TAKEN ON PORTION
OF CHAIN WHICH HAS MOST PASSED OVER THE SPROCKET.
IF MEASUREMENT TAKEN IS 4.810 INCHES OR MORE. CHAIN SHOULD BE REPLACED.
Figure 5. MHP3427
1/4
(6 mm)
IF VISUAL CHECK REVEALS NO DEFECTS, PROCEED AS FOLLOWS:
LAY USED CHAIN ON FLAT SURFACE AND MEASURE BETWEEN SEVEN (7) LINKS AS
SHOWN. MEASUREMENT SHOULD BE TAKEN ON PORTION OF CHAIN WHICH HAS
MOST PASSED OVER THE POCKET WHEEL.
IF MEASUREMENT TAKEN IS 5.355 OR MORE. CHAIN SHOULD BE REPLACED.
(136 mm)
Figure 4, p. 11
VERNIER CALIPER
(19 mm) .750 PITCH
5.250 NEW CHAIN
(133 mm)
and
Figure 5, p.
11. IT IS NOT
11
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