— 19 —
Item
Inspection methods
Discard limit/criteria
Remedy
4. Hook
(1) Deformation
Check visually.
･
No deformation from original
shape (at time of purchase).
Replace.
Measure dimension
“e” between two
embossed marks at
time of purchase with
calipers.
･
No deformation from original
shape (at time of purchase).
Replace.
Measure with
calipers.
･
Dimensions “c” and “d” are within
their limits.
Replace.
(Reference values)
c mm
d mm
Normal
size
Discard
limit
Normal
size
Discard
limit
Bottom hook 17.0
16.2
12.1
11.5
Top hook 17.0
16.2
7.0
6.5
480
kg
Bottom hook
23.5 21.0 17.5 16.0
Top hook
(2) Flaws
Check visually.
･
No deep flaws.
Replace.
(3) Bend at shank of
bottom hook
Check visually.
･
Never use if bent.
Replace.
(4) Bottom hook
movement
Turn hook.
･
Hook should turn lightly.
Replace.
(5) Deformation of
bottom yoke
Check visually.
･
Should be free from deformation.
Replace.
(6) Hook latch
Check visually.
･
No deformation from original
shape (at time of purchase).
Replace.
(7) Rotation of idle
sheave
Turn idle sheave by
lifting the load chain
up and down, as
illustrated.
The idle sheave rotates smoothly.
Inspect and repair if
rotation is not
smooth.
Top hook
Bottom hook
