Product Manual

10
Figure 6
Figure 7
9.0 Pre-Operation Inspection
9.1 Limit Switch Inspection
1. Press UP button.
2. While the hook moves up, raise the limit switch
paddle where the chain enters the hoist.
3. Hook should immediately stop.
4. Check DOWN limit switch in similar manner.
9.2 Inspecting the Load Chain
Clean the chain with a solvent, and carefully
inspect the entire load chain. The chain should be
visually checked before each day’s use. Replace
damaged chain before using the chain hoist.
Replace the load chain if any of the following are
identified:
1. Seriously rusted or cracked.
2. Marks on the chain surface are deeper than
5% of the link’s diameter.
3. Links are twisted or deformed.
4. The links are stretched too long or seriously
worn on the surface, especially at the points
where links contact each other. To check the
links for stretch, proceed as follows:
5. Select an unworn, un-stretched length of chain
(at the slack end for example). Let the chain
hang vertically with a light load (about 20
pounds) on the chain to pull it taut.
6. Use a large caliper to measure the outside
length of a convenient number of links.
Measure the same number of links in a used
section of chain and calculate the percentage
increase in length of the worn chain.
7. If the length of the worn chain is more than 1-
1/2% longer than the unused chain, then the
chain should be replaced. If the chain is worn
less than 1-1/2%, check it at several more
places along its length. If any section is worn
more than 1-1/2%, the chain should be
replaced.
Never extend load chain by welding a second
piece to the original.
Do not operate the hoist with a
twisted, kinked or damaged load chain. Do not
splice the load chain.
Check that the chain does not twist along its length
from hoist to hook. If twist is present on units with
multiple falls, the hook must be passed back
through the chain loop to remove all twist in the
chain.
The load chain supplied with
your JET chain hoist is designed,
manufactured, and tested for proper fit and
durability. Over a period of time, the chain may
need to be replaced. For your own safety, use
factory replacement chain only. Use of other
than factory replacement chain may cause
serious injury and/or damage to the hoist.
9.3 Inspecting the Hooks
It is important to check top and bottom hooks for
proper opening and other signs of deformation or
damage. Replace a hook immediately if any of the
following problems are identified:
1. The safety latch no longer contacts the hook
opening.
2. The vertical angle at the neck of the hook
reaches 10° (see Figure 8).
3. Chemical corrosion or cracks on the hook.
4. Excessive wear on the inside surface.
5. The throat opening has enlarged wider than
the maximum permissible 10% increase, as
shown in Figure 9.