How To Inspect The Hook - Hitachi L Series Service Manual

6-7. How to inspect the hook

1. Inspection of cracks and wear and usage limit of the hook opening
When checking the upper and lower hooks, if the following situations are confirmed, please do not use in that
state and ensure to replace the hook.
(1 ) The opening of the hook has increased.
(2 ) There is a crack.
(3 ) The wear of the parts that come into contact with steel or the hanging bracket etc. exceeds the limiting
value.
2. Opening dimensions of the hook and limiting wear amount
Measure the opening size (dimension between punch marks) and wear amount of the hook. Ensure to replace
when the following conditions are not satisfied.
(1 ) Opening dimensions of the hook
Measure the dimension A between the punch marks and compare it with the value measured before using
the product to ensure there is no deformation.
* Measure the dimension A between punch marks as follows.
2 ) Thickness dimension of the hook
Measure the thickness dimension H of the hook and compare it with the value measured before using
the product to ensure it is 95% or more of the original value.
* The A and H dimensions in the table below are standard values at the time of production.
H
3. Slack of hook installation bolts, nuts, split pins etc. and the presence of dropping offs
The bolts, nuts and split pins should not have slack or any dropping offs ; they must be affixed securely.
4. Deformation or metal fittings preventing detachment
The metal fittings are not deformed or have not dropped off. The bolts, nuts, springs do not have slack or
dropping off, and they are securely affixed.
unit: mm
A 50
Upper hook 24
Lower hook 21
A
H
- 23 -
Punch mark