9
JLC680-2 Rev AA
April 2019
Figure 4 — Chain Replacement Diagram
CHAIN REPLACEMENT WITH NO CHAIN IN HOIST
Refer to Figure 4.
1. DISCONNECT HOIST FROM POWER SUPPLY and move hoist
to a work table. Remove the electrical cover, electrical panel
and the electric brake assembly.
2. Detach the chain stripper from the bottom of the hoist.
3. Insert the new chain between the load sheave and the chain
guide. Feed the chain into the hoist by manually turning the
brake hub adaptor. Allow about 15" of chain below the hoist
on the slack end. Be sure the welds of the upstanding links are
out away from the load sheave and that proper orientation is
observed for attachment of the slack end. Also be sure the load
hook assembly (if already attached to the chain) is toward the
center of the hoist or to your right looking from the motor end.
4. Reinstall the chain stripper (with the chain support on double-
chained hoists, See Figure 4) observing proper chain alignment
and avoiding any twist in the chain.
5. Follow steps 11 through 14 in previous section, CHAIN
REPLACEMENT WITH CHAIN IN HOIST, to complete the chain
replacement procedure.
NOTE: Inspect chain guides and load sheave for wear, replace as
needed.
5-5 LIMIT SWITCH ADJUSTMENT
IMPORTANT:
Before placing hoist in operation, check the limit
switch adjustment. Limit switches are provided to protect the hoist
against damage resulting from overtravel or to allow setting the hook
travel within the factory-set limits of travel. The standard limit switch
is designed for lifts of 50 ft or less on single-chained hoists and 25 ft
or less on the 2 ton, double-chained models. The long lift limit switch
allows for the maximum amount of lift, which is 143 ft on the 1 ton
and under models, and 71 ft on the 2 ton models.
The upper and lower limit switch adjusting nuts are color-coded
gold and silver respectively. Each limit nut has 10 slots for fine
adjustment, and the increment of adjustment is such that one slot is
equivalent to approximately one link of chain travel with the standard
limit switch. Movement of the limit switch nuts toward or away from
each other decreases or increases the hook travel respectively.
ADJUSTING UPPER LIMIT (GOLD NUT)
Refer to Figure 3.
1. Suspend the hoist. For single chain models raise the load
block until there is a minimum clearance of 2" from the hoist
housing and the top of the block. Double chain models require
a minimum clearance of 1" from the chain support to the top of
the load block.
2. DISCONNECT HOIST FROM POWER SUPPLY and remove the
electrical cover.
3. With a screwdriver, pry the spring guide plate out of the slots in
the limit switch nuts.
4. Turn the slotted gold nut toward its limit switch until the switch
“clicks” then turn two slots farther. Release the spring guide
plate and be sure it slips back into the slots in both limit
switch nuts. Do not disturb the silver slotted nut if it has
been set previously.
ADJUSTING LOWER LIMIT (SILVER NUT)
Refer to Figure 3.
1. Suspend the hoist. Carefully lower the load block to a point
where the slack-end loop of the chain hangs down 6" or more
from the hoist housing (or the limit desired in any particular
application allowing the minimum 6"). There should be a
minimum clearance of 1-1⁄2" between the chain stop and
bottom of hoist.
2. DISCONNECT HOIST FROM POWER SUPPLY and remove the
electrical cover.
3. With a screwdriver, pry the spring guide plate out of the slots in
the limit switch nuts.
4. Turn the slotted silver nut toward its limit switch until the switch
“clicks,” then turn two slots farther. Release the spring guide
plate and be sure it slips back in the slots in both limit
switch nuts. Do not disturb the gold slotted nut if it has
been set previously.
CHECK BOTH UPPER AND LOWER LIMITS
1. Connect the hoist to the power supply. Be sure the green
ground wire is properly grounded (See Installation 3-b, page 5).
2. Check load hook direction (See Installation 3-c, page 5).
3. Carefully raise load block to upper limit and observe if it stops
automatically at desired level. Do not allow load block to run
into hoist housing — this will damage the hoist. Maintain a
minimum clearance of 2" from the hoist housing and the top
of the load block on single-chained models and 1" from the
chain support to the top of the load block on double-chained
models.
4. Carefully lower load block to lower limit and observe if it stops
automatically at the desired level. Do not allow slack-end loop
of chain to become taut against hoist housing. This will damage
the hoist. There should be a minimum clearance of 11⁄2"
between the chain stop and the bottom of the hoist.
5. If upper and lower limits operate satisfactorily, hoist is ready for
use. If they are not as desired, repeat adjustment.
If the wires running to the limit switches are ever disconnected
for any purpose, be sure to replace wires in accordance with the
correct wiring diagram (See Figures 9A, 9B, 9C & 9D).
5-6 BRAKE
Properly adjusted, this brake will release promptly when energized.
It is capable of both smoothly stopping and securely holding the
rated capacity of the hoist. If the hoist develops either undesirable
over-travel after the pushbutton is released (this condition is most
noticeable in the lowering direction) or hesitates to lift the load
promptly when the pushbutton is depressed (this condition is most
noticeable in the hoisting direction), the brake should be adjusted.
BRAKE ADJUSTMENT
Refer to Figure 5.
1. DISCONNECT HOIST FROM POWER SUPPLY and remove the
electrical cover.
2. With reference to Figure 5, the gap between the brake
armature “A” and the field “B” should be checked. The
correct gap is 0.015". Adjustment should not be necessary
until gap reaches 0.040".
3. Adjust the gap using a 9/16" wrench on the 3 locknuts “F”.
Check with a feeler gauge to be sure the gap is the same on
both ends of the solenoid.
4. Adjustment is now complete and the brake properly set.
Replace the electrical cover, reconnect the power supply,
and check hoist brake action.
Содержание Coffing JLC Series
Страница 35: ...33 JLC680 2 Rev AA April 2019 FIGURE 23 TRANSMISSION...
Страница 37: ...35 JLC680 2 Rev AA April 2019 FIGURE 24 CHAINING PARTS...
Страница 39: ...37 JLC680 2 Rev AA April 2019 NOTES...
