Quad Fall Hoist (6 and 25 ton)
A
B
C
D
E
F
G
H
J
K
L Lower Hook Block
(Dwg. MHP2830)
Refer to Dwg. MHP2830 on page 9,
L.
Lower Hook Block.
To feed load chain through bottom hook assembly:
1. Install the ‘C’ link in the last link of the load chain extending from the hoist (B).
Connect the new load chain to the ‘C’ link. The end link must be a standing link
(perpendicular to the axle of hoist sprockets).
2. Run the hoist to feed the chain through the hoist body and down to (D) on the
hook block.
3. The axis of the sprocket wheel (120) in hook block assembly must be
perpendicular to the rotation axle of hoist sprockets (30) and (50) of the hoist.
4. Insert the last link of the load chain in the opening to bottom block (D). The first
link must be inserted parallel to the axis. The sprocket of bottom hook assembly
and the following standing links must have the welds turned to the outside
position with the sprocket. Refer to Dwg. MHP0472 on page 7.
5. After exiting the bottom hook assembly at (E), feed the last link of the load chain
into hoist opening (F) and around sprocket (50).
6. After exiting the hoist at (G), run load chain down to (H) on the hook block. Feed
load chain through opening.
7. After exiting the bottom hook assembly at (H), position the last link of the load
chain in the slot (K) in the chain guide housing (58) and attach it with capscrew
(41) and lockwasher (44).
WARNING
• The chain must not be twisted.
8. On the free end of the load chain, install buffer (4) with capscrew (5) and nut
(7) (this buffer activates the bottom switch limit). As a minimum attach the
buffer to the 9th link from the load chain end.
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Disassembly
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General Disassembly Instructions
Refer to the Product Parts Information Manual for drawings and item numbers
referenced in the “MAINTENANCE” section, unless otherwise noted.
The following instructions provide the necessary information to disassemble, inspect,
repair, and assemble the hoist. Parts drawings are provided in the Product Parts
Information Manual.
If a hoist is being completely disassembled for any reason, follow the order of the
topics as they are presented.
It is recommended that all maintenance work on the hoist be performed in a clean
dust free work area.
In the process of disassembling the hoist, observe the following:
1. Never disassemble the hoist any further than is necessary to accomplish the
needed repair. A good part can be damaged during the course of disassembly.
2. Never use excessive force when removing parts. Tapping gently around the
perimeter of a cover or housing with a soft hammer, for example, is sufficient to
break the seal.
3. Do not heat a part with a flame to free it for removal, unless the part being heated
is already worn or damaged beyond repair and no additional damage will occur
to other parts.
In general, the hoist is designed to permit easy disassembly and assembly. The
use of heat or excessive force should not be required.
4. Keep the work area as clean as practical, to prevent dirt and other foreign matter
from getting into bearings or other moving parts.
5. All seals, gaskets and ‘O‘ rings should be discarded once they have been removed.
New seals, gaskets and ‘O‘ rings should be used when assembling the hoist.
6. When grasping a part in a vise, always use leather-covered or copper-covered vise
jaws to protect the surface of the part and help prevent distortion. This is
particularly true of threaded members, machined surfaces and housings.
7. Do not remove any part which is a press fit in or on a subassembly unless the
removal of that part is necessary for repairs or replacement.
8. When removing ball bearings from shafts, it is best to use a bearing puller. When
removing bearings from housings, drive out the bearing with a sleeve slightly
smaller than the outside diameter of the bearing. The end of the sleeve or pipe
which contacts the bearing must be square. Protect bearings from dirt by keeping
them wrapped in clean cloths.
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Hoist Disassembly
NOTICE
• It is recommended to remove load chain and chain bucket for a complete
hoist disassembly.
1. Shut off, bleed down air supply then disconnect and tag air lines.
2. Remove hoist from its mounting and place in clean work area on a sturdy work
bench.
3. Position several blocks of wood on the work bench and stand the hoist in a vertical
position with the motor end up.
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Motor and Disc Brake Removal
Refer to Dwgs. MHP2999, MHP2652, MHP3037 and MHP3038.
Use the following procedure to remove the motor.
1. Remove four capscrews (74) and lockwashers (75) that secure air motor assembly
to the hoist body (36) and remove motor assembly.
2. Remove and discard gasket (7).
3. Store motor in a clean and dry area until further disassembly is necessary.
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Motor Disassembly
3.5 HP
Refer to Dwg. MHP2652.
1. Remove motor and disc brake assembly as described in
‘Motor and Disc Brake Removal’ on page 9.
2. Remove capscrews (34) and cover plate (92).
3. If hoist is equipped with rope control and/or emergency stop refer to Dwgs.
MHP2662 and/or MHP3037 for removal.
NOTICE
• It is not necessary to remove check valve (77) unless replacing ball (47) and
‘O‘ rings (53).
• It is not necessary to remove pendant adapter plate (605) or (613) or rope
control block (313) or (405) unless valves (86) and (87) require
replacement.
4. Remove and discard gasket (91).
5. Remove check valve (77), ‘O‘ rings (53) and ball (47).
6. Remove capscrews (90) and remove motor cover (83) from motor housing (76).
7. Remove and discard ‘O‘ rings (70).
8. Remove exhaust washers (81) from motor cover (83).
9. Remove valve assemblies (86) and (87) and springs (84).
10. Remove ‘O‘ rings located on valves (86) and (87) if necessary, (to remove 'O' rings,
it is necessary to cut them).
NOTICE
• Two bearings (78) mounting in the motor housing are bonded with Loctite®
603 or equivalent. Remove idle gear (79) and drive gear (80) only if
necessary, use a bearing punch (Ingersoll Rand pn: 96441232) or a standard
drift punch and a hammer. Refer to Dwg. MHP2644 on page 15.
11. Remove drive gear (80) and idle gear (79) from housing (76)
12. Remove bearings (78) from drive gear (80) and idle gear (79) only if replacement
is necessary (use a suitable bearing extractor).
13. It is necessary to remove plug (1) and washer (151) from housing (76) this will
release the brake housing (61).
6 HP
Refer to Dwg. MHP2999.
1. Remove motor and disc brake assembly as described in
‘Motor and Disc Brake Removal’ on page 9.
2. Remove capscrews (34) and cover plate (92).
3. If hoist is equipped with rope control and/or emergency stop refer to Dwgs.
MHP2662 and/or MHP3038 for removal.
Form MHD56279 Edition 4
9
