Manitowoc 2250 Service Maintenance Manual

Reference Only
BOOM 2250 SERVICE/MAINTENANCE MANUAL
4-6
Published 07-19-16, Control # 249-01
PHYSICAL BOOM STOP
General
See Figure 4-4 for the following information.
The physical boom stop assembly serves the following
functions:
• Assists in stopping the boom smoothly at any angle
above 80
°.
• Assists in preventing the boom rigging from pulling the
boom back when traveling or setting loads with the
boom at any angle above 80
°.
• Assists in moving the boom forward when lowering the
boom from any angle above 80
°.
• Provides a physical stop at 90
°.
The strut cylinders between the boom stop tubes and the
boom butt have two positions:
• Working position (struts fully extended)—The physical
boom stop must be in this position for all crane
operations.
• Shipping position (struts fully retracted)—This position
provides maximum clearance for shipping the boom butt
with the physical boom stop installed.
Operation
See Figure 4-4 for the following description.
1. Air system pressure of 8,6 to 9,4 bar (125 to 137 psi) is
trapped in the boom stop cylinders by a check valve
connected to each cylinder’s inlet port as shown in View
A.
2. When the boom is raised to 80
°, the boom stop rod ends
contact the boom stop pins in the adapter frame as
shown in View B.
3. The cylinder rods then start to compress the air, which is
trapped in the boom stop cylinders by the check valves.
4. As the boom is raised higher, the pressure of the trapped
air increases to exert greater force against the boom.
5. If for any reason the boom is raised to 90
°, the boom
stop cylinders fully compress the air and bottom out to
provide a physical stop.
Maintenance
Weekly
Inspect the air cylinders and piping for air leaks.
Quarterly—Adding Oil to the Boom Stop
Cylinders
See Figure 4-4 for the following procedure.
1. Lower the boom stop to the shipping position (see
Lowering the Boom Stop to the Shipping Position
).
NOTE: It is necessary to exhaust the air from the boom
stop cylinders before performing step 3
.
2. Crack open the air line at each check valve to exhaust
air from the boom stop cylinders.
3. Disconnect the hose from each check valve and squirt a
few drops of light engine oil into the check valve.
4. Reconnect the hoses to the check valves.
Lowering the Boom Stop to the Shipping
Position
See Figure 4-4 for the following procedure.
1. Lower the boom onto blocking at ground level.
2. Keep the engine running to ensure that there is sufficient
air pressure to fully extend the strut cylinders.
3. Remove the quick-release pin from each strut support.
4. Rotate the supports to the shipping position as shown.
5. Reinstall the quick-release pins in the strut supports.
6. Stop the engine.
7. Disconnect the socket from the plug in the air supply
line, near the right side boom hinge pin as shown in View
C.
The socket will block the supply air. Air pressure in the
lines and cylinders will exhaust through the plug.
WARNING
Boom Hazard!
The physical boom stop does not automatically stop the
boom at the maximum operating angle. The automatic
boom stop must be installed and properly adjusted to stop
the boom (see Automatic Boom Stop on page 4-1
).
Otherwise, death or serious injury could occur.
Make sure the physical boom stop is installed for all crane
operations.
WARNING
Crushing Injury Hazard!
The strut cylinders will retract as the air pressure
exhausts, creating a hazardous situation in which death or
serious injury may occur.
Stand clear of the boom stop tubes while performing
step 7
.

Manitowoc 2250 Specifications

General

Brand	Manitowoc
Model	2250
Category	Construction Equipment
Language	English