General Disassembly
The following instructions provide necessary information to disassemble, inspect, repair, and assemble the hoist. Hoist assembly parts drawings are provided in “PARTS” section.
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 be performed on a bench.
In the process of disassembling the hoist, observe the following:
1.Never disassemble hoist any further than is necessary to accomplish 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 apply heat to a part to free it for removal unless 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.
Use of heat or excessive force should not be required.
4.Keep work area as clean as practical, to prevent dirt and other foreign matter from getting into bearings or other moving parts.
5.When grasping a part in a vise, always use
6.Do not remove any part which is press fit in or on a subassembly unless removal of that part is necessary for repairs or replacement.
Hoist Disassembly
Brake Disc Replacement
1.Unscrew
2.Lift hand chain guides (35) off stay bolts on side plate 1 (1). Remove hand chain (46) from handwheel (31).
3.Remove cotter pin (34), unscrew pinion nut (33) and remove washer (32).
4.Remove handwheel (31) by holding load chain (46) and rotating handwheel (31) counterclockwise until it can be lifted off pinion shaft (13).
5.Remove brake cover (30) and brake disc A (27).
6.Remove ratchet gear (29) and brake disc B (28).
Overload Clutch Disassembly
1.Refer to previous instructions for removal of wheel cover
2.Use a small punch to bend tab on washer (81) out of slot in nut (82).
3.Firmly grip outside of overload clutch assembly then use clutch adjusting socket part number 71112064 to remove nut
(82)from supporter (78).
4.Separate remaining parts of overload clutch assembly.
Cleaning, Inspection and Repair
Use the following procedures to clean, inspect and repair components of the hoist.
Cleaning
Clean all hoist component parts in an acid free solvent (except for brake discs). Use of a stiff bristle brush will facilitate removal of accumulated dirt and sediments on gears and frames. Dry each part using low pressure, filtered compressed air.
Inspection
All disassembled parts should be inspected to determine their fitness for continued use. Pay particular attention to the following:
1.Inspect all gears for worn, cracked, or broken teeth.
2.Inspect shafts for ridges caused by wear. If ridges caused by wear are apparent on shafts, replace shaft.
3.Inspect all threaded items and replace those having damaged threads.
4.Measure thickness of brake discs. If brake discs do not have uniform thickness or are less than 5/64 in. (2 mm) thick replace brake discs.
Repair
Actual repairs are limited to removal of small burrs and other minor surface imperfections from gears and shafts. Use a fine stone or emery cloth for this work.
1.Worn or damaged parts must be replaced. Refer to applicable parts listing for specific replacement parts information.
2.Inspect all remaining parts for evidence of damage. Replace or repair any part which is in questionable condition. The cost of the part is often minor in comparison with the cost of redoing the job.
3.Smooth out all minor nicks, burrs or galled spots on shafts, bores, pins and bushings.
4.Examine all gear teeth carefully, remove nicks and burrs.
5.Polish edges of all shaft shoulders to remove small nicks which may have been caused during handling.
6.Remove all nicks and burrs caused by lockwashers.
Hoist Assembly
•The brake will not operate properly if there is too much oil on brake discs (27 and 28). Excessive oil or grease on brake components could cause load to slip.
1.Dip replacement brake discs (27 and 28) in ISO VG32 hydraulic oil or SAE 10 oil for two seconds. Wipe off excess oil.
2.Place brake disc B (28) over hub (26). Brake disc B (28) has a smaller outside diameter than brake disc A (27).
3.Install ratchet gear (29) on hub (26) so recessed face fits over brake disc B. Teeth of ratchet gear (29) must engage pawl (24). Ratchet gear (29) should not rotate counterclockwise and should “click” when rotated clockwise.
4.Place brake disc A (27) on ratchet gear (29).
5.Place brake cover (30) over stay bolts on side plate 1 assembly (1).
6.With brake surface of handwheel (31) towards brake disc A (27), place handwheel (31) on pinion shaft (13). Rotate handwheel (31) clockwise until clicking occurs. Hold load chain (47) if necessary.
7.Place washer (32) over pinion (13). Install pinion nut (33) and cotter pin (34) using “Brake Adjustment.”
MHD56012 - Edition 8 | 11 |