Crown RC 5500 series - Fork Inspection

339
M7.8-04.2-001
05 Rev. 11/08
LIFTING MECHANISM
Fork Inspection
Fork Inspection
WARNING
The following causes of fork failure may mean loss of
equipment, damaged materials, bodily injury or loss of
life. Make an inspection and measurement of the forks
at each planned maintenance interval to check for
wear, overload, fatigue, bends, etc. Refer to “Lubrica-
tion and Adjustment” chapter.
WARNING
• Use the proper fork for how it was designed to be
used.
• Avoid using fork extensions.
• Do not modify forks.
• Only qualified personnel should make repairs.
• Visually inspect forks each work day.
Abrasion
Abrasion gradually reduces the thickness of the fork.
Be sure the fork thickness is within specifications. Do
not allow forks to rub the floor during normal operation.
If forks rub floor, check lift chain adjustment. Fork wear
at the heel must not exceed 10 percent of the original
thickness. At this point forks are adequate for approxi-
mately 80 percent of rated capacity. Refer to Chart 2.
Use fork wear calipers, part no. 107330, or a measur-
ing instrument such as a vernier or good 160 mm
(6.0 in) scale. For allowable fork wear thickness, refer
to Chart 1.
If using the fork wear calipers, refer to the following:
Refer to Figure 16854-01. The fork wear calipers have
two measuring points or jaws. The inside jaws (2) mea-
sure 10% less than the outside jaws (1).
Refer to Figure 16855-01. To set the outside jaws,
measure the thickness of the middle of the shank (this
point receives almost no wear). Set the calipers to the
“feel” of the shank by lightly tapping on them with a
metal object.
NOTE
Care should be taken when using the calipers to hold
them square across the shank or an incorrect reading
will result.
Allowable Wear Thickness Chart 1
Standard Fork
Thickness
Allowable 10% Wear
Fork Thickness
mm in mm in
31.5 1.25 28.5 1.12
38.0 1.50 35.0 1.38
44.5 1.75 39.5 1.56
51.0 2.00 46.0 1.81
57.0 2.25 51.0 2.00
63.5 2.50 57.0 2.25
Figure 16854-01
1 Outside Jaws 100% (Fork Shank)
2 Inside Jaws 90% (Fork Blade)
Crown 1988 PF7393-1 Rev. 11/08