Manitowoc 2250 Service And Maintenance Manual

Reference Only
INTRODUCTION 2250 SERVICE/MAINTENANCE MANUAL
1-38
Published 11-06-15, Control # 040-13
When Drum 1, 2 or 3 load drum brake solenoid (AS-7, AS-9
or AS-11) is disabled, pilot pressure is exhausted from brake
relay. Brake relay valve closes, exhausting sealing air from
quick release valves diaphragms, to exhaust air from brake
cylinders. Brake cylinder springs apply brakes.
Working (Service) Brakes
The working brake part of cylinder chamber is controlled with
selected drum working brake pedal. Working brake relay
shifts to allow manifold air flow to working brake cylinder
chamber, compressing spring and applying brake band
against drum.
Pressure applied by brake is in proportion to brake pedal
movement. Full brake application is obtained when brake
pedal is applied and latched. When brake pedal is released,
working brake is released at the same rate as pedal
movement until completely released.
Load Drum Clutch Release System
Front or rear load drum clutches are air controlled and are
spring-applied/air-released. The PC controls the clutches
with air pressure switches, selected load drum control
handle movement, depending on mode and circuit
requirements. The PC monitors air pressure switches when
operator switches from one load drum to another. The clutch
and brake air lines are connected through shuttle valve to
pressure switch. The PC waits until pressure switch closes
before stroking the pump and releasing the selected drum
brake.
When circuit to selected load drum clutch solenoid AS-8, AS-
10, or AS-12 is open, manifold pressure is blocked and air is
exhausted from drum clutch cylinder. Clutch spring-applies
to connect drum shaft to motor.
When selected load drum control handle is moved an input
signal is sent to the PC. The PC sends an output signal to
clutch solenoid AS-8, AS-10, or AS-12. The PC selects
PEDAL
M
M
M
F-12
BRAKE
SOLENOID
BRAKE
RELAY
REGULATOR
WORKING
BRAKE
RELAY
WORKING
BRAKE
NOT USED
CLUTCH
CYLINDER
BRAKE
CYLINDERS
QUICK
RELEASE
VALVE
AS7 (DRUM 1)
AS9 (DRUM 2)
AS11 (DRUM 3)
QUICK
RELEASE
VALVE
LOAD DRUM
CLUTCH
VALVE
AS8 (DRUM 1)
AS10 (DRUM 2)
AS12 (DRUM 3)
LOAD
DRUM
DRUM
FLANGE
FIGURE 1-20
8D
PRESSURE SWITCH
(CURRENT PRODUCTION)
89V (DRUM 1)
89U (DRUM 2)
89R1 (DRUM 3)

Manitowoc 2250 Specifications

General

Brand	Manitowoc
Model	2250
Category	Construction Equipment
Language	English