KNIGHT D-SERIES SERVO HOIST OPERATION MANUAL
SECTION 4
MAINTENANCE
21
4.4.2 Periodic Inspection (Documented)
This is a thorough examination of the hoist and its chains conducted by a qualified person,
making records of external conditions to provide a basis for the hoist’s continuing evaluation.
This Inspection should be carried out at the following intervals:
A. Light Service
or
Service Class 0/1
–
Yearly
(equipment remains in place).
B. Moderate Service
or
Service Class 2
–
Every Six Months
(equipment remains in place unless external conditions indicate that disassembly
should be done to permit detailed inspection).
C. Heavy Service
or
Service Class 3
–
Every Three Months
(equipment remains in place unless external conditions indicate the disassembly
should be done to permit detailed inspection).
D. Very Heavy Service
or
Service Class 4
–
Every Six Weeks
(equipment remains in place unless external conditions indicate that disassembly
should be done to permit detailed inspection).
4.4.2.1 Recommendations for Periodic Inspections
Perform the inspection detailed under section 4.4.1.1 “What to Look for
During a Frequent Inspection” of this manual.
Next, the chains should be cleaned for inspection, using any cleaning method that will not
cause damage. Adequate lighting should be provided for the person inspecting the
chain. The chain should be examined link by link for cracks, gouges, nicks, distortion,
corrosion, deposits of foreign material, and for interlink wear. To inspect for wear at the
interlink contact points, slacken the chain and rotate adjacent links to expose the inner
ends of the link. If wear is observed or if elongation is suspected, measure the chain.
Knight recommends using the Knight Load Chain Gauge (KSAA1003) for quick GO / NO
GO checks of chain length.
A. Chain Link Thickness
If chain is worn to less than the minimum allowable thickness (T),
remove the chain from service. (Refer to Figure 4-2)
Figure 4-2
Minimum Allowable Chain Link Thickness at Any Point
Nominal Chain Size
Minimum Thickness “T”
Inches
mm
Inches
mm
.157
4.0
.137
3.48
.196
5.0
.171
4.35
Table 4-2
T
