Coffing Hoists EC Series, Operating, Maintenance & Parts Manual

15

P/N EC680-7 April 2017

Order # 5041558-0 & 5041679-0

SECTION V MAINTENANCE AND REPEAT

5-1. GENERAL

This section provides instruction for the most common routine 

maintenance and adjustments. Major repairs are not within the 

scope of this manual and should be referred to qualified service 

facilities.

Safety Notice

Always remove load and disconnect hoist from power supply 

before removing end covers or making repairs.

5-2. LIMIT SWITCH ADJUSMENT

Limit switches are provided to protect the hoist against damage 

resulting from overtravel. For easy identification the upper (No. 2, 

Figure 5-1) and lower (No. 3, Figure 5-1) limit switch adjusting nuts 

are colored brass and zinc respectively. Each limit switch nut has ten 

slots for adjustment, and the increment of adjustment is such that one 

slot is equivalent to one link of chain travel. Care should be exercised 

when adjusting either limit of travel. When a geared type limit switch is 

furnished (long lift hoists) each adjustment is equal to 3 links of chain, or 

30 links per revolution.

FIGURE 5-1. LIMIT SWITCH ADJUSTMENT

a.  Adjusting Upper Limit (Brass Nut).

1. -Carefully raise the load block to a point where its top is 2” 

or more from the hoist housing

2. Disconnect Power from the hoist and remove the short end 

cover.

3. With a screwdriver, pry the spring guide plate (No. 1, Figure 5-1) 

out of the slots in the colored limit switch nut (Nos. 2 and 3).

4. Turn the slotted brass nut (No. 2) toward its limit switch until 

the switch clicks.

5. Release the spring guide plate and be sure it snaps back 

into the slots in both nuts. Do not disturb the other slotted 

nut if it has been previously set.

6. Replace the short end cover and reconnect power to the hoist.

7. Carefully raise the load block to its upper limit and observe 

to see if it stops automatically at the desired point. Do 

not allow the load block to run into the hoist housing. The 

stopping point should be at least 2” below the hoist housing.

b.  Adjusting Lower Limit (Zinc Nut)

1. Carefully lower the load block to a point where are least 12 

links of slack chain hang down from the hoist housing.

2. Disconnect power from the hoist and remove the short end cover.

3. Adjust the zinc limit switch nut in the same manner 

described above for the brass nut.

4. Replace the short end cover and reconnect power to the hoist.

5. Carefully lower the load block to its lower limit and observe 

if it stops automatically at the desired level. Do not run chain 

out of hoist or allow the slack end loop to become taut 

against the hoist housing. At least 12 links of slack chain 

should hang from the hoist.

Notice

If upper and lower limits are not operating satisfactorily, 

repeat adjustment.

5-3. MOTOR BRAKE ADJUSTMENT

When properly adjusted, the multiple disc motor brake should 

release promptly, operate without noticeable chatter, and stop the 

load with no more than one inch of drift. If the hoist hesitates to lift 

the load promptly when the pushbutton is depressed, the brake 

should be adjusted per the following procedure.

a.  Remove any load and disconnect power from hoist.

b.  Remove the short end cover.

c.  Referring to Figure 4-2, check the gap between armature (A) 

and frame (B). the correct gap is .015”

d.  Adjust the gap by turning the three lock nuts (F) and check with 

a feeler gauge to be sure the gap is the same on both ends of 

the solenoid.

FIGURE 5-2. MOTOR BRAKE ADJUSTMENT

Be sure the bottom of the armature does not touch the 

splined adapter (H). As wear occurs, the original clearance 

will be reduced. When this clearance is gone, THE BRAKE 

DISCS MUST BE REPLACED.

e.  Replace short end cover and reconnect power. If the brake 

still chatters or is hesitant to release, refer to Section VI, 

Troubleshooting.

5-4. TOP SUSPENSION REMOVAL  

AND REPLACEMENT

A number of different top suspension assemblies are available to 

accommodate different methods of hanging the hoist. If it should be 

necessary to change top suspensions, proceed as follows:

a.  Disconnect power from hoist and move the hoist to a safe working 

area. If necessary, remove trolley and/or rotate suspension lug 

to gain access to the socket head cap screws bolting the top 

suspension yoke to the frame of the hoist.

b.  Remove socket head screws (7/16” hex) and lift out the 

suspension assembly.