Published 08-25-09, Control # 077-04 6-1
RT9130E SERVICE MANUAL SWING SYSTEM
SECTION 6
SWING SYSTEM
DESCRIPTION
The purpose of the swing system is to allow the crane
superstructure to rotate atop the carrier frame. The
superstructure swing system provides full 360 degree
rotation in both directions and is equipped with free swing
capabilities. The term free swing means that, with the
SWING BRAKE switch in the OFF position, the
superstructure will swing freely after the SWING control lever
is released until it coasts to a stop or the glide swing brake
pedal is depressed.
Swing is activated using the control lever in the cab. When
the swing lever is actuated, hydraulic pressure is routed to
the swing motors to drive the swing gearboxes in the
appropriate direction. As the gearboxes rotate, their pinion
gears mesh with the teeth on the swing bearing and rotate
the superstructure. Swing speed can be controlled by the
control lever and a HIGH/LOW swing speed switch on the
front console. The maximum rotation speed is 2.5 rpm in
HIGH speed and 1.25 rpm in LOW speed. Braking is
accomplished by depressing a glide swing brake pedal
which is a proportionate control valve that provides a
controlled braking of the swing motion.
The swing system consists of a hydraulic remote controller,
swing speed switch, series/parallel selector valve, a
directional control valve, the swing drives, the swing brake
assemblies, the brake pedal and power brake valve, and a
swing brake release solenoid valve.
The crane is equipped with a pin type swing lock as standard
and a standard 360 degree positive swing lock. The 360
degree positive swing lock meshes with the swing gear teeth
at any point of rotation. The pin type swing lock will only lock
the turntable in a straight ahead position over the front or
rear of machine. Both swing locks are operated from the cab.
THEORY OF OPERATION
Swing Drive
The hydraulic power for the swing drive is supplied by the
engine driven hydraulic Pump No. 1. Oil flows from the pump
to the hydraulic Port 5 swivel. Flow from the swivel is routed
to the front steering flow divider valve in the swing directional
control valve. Bypass flow from the flow divider valve is used
to supply the swing directional control valve.
When the hydraulic remote control is positioned to select
right or left swing, the flow through the control valve is
directed to the series/parallel valve, and then routed to the
swing motors. If the SWING BRAKE selector switch is in the
OFF position, the superstructure will rotate in the desired
direction. Shifting the control to neutral and depressing the
brake pedal will stop the swing.
Swing Brake
The hydraulic power for the swing brake is supplied by the
pressure reducing/sequence valve in the swing brake and
armrest lockout manifold. With the SWING BRAKE selector
switch positioned to ON, the swing brake release valve
blocks the regulated flow to the brake release ports and
spring pressure in the swing brakes applies the brakes.
When the SWING BRAKE selector switch is positioned to
OFF, the regulated flow is directed from the pressure
reducing/sequence valve to the brake release ports,
overcoming the brake spring pressures and releasing the
swing brakes. Regulated flow from the pressure reducing/
sequence valve is also provided to the power brake valve
where it is available for the activation of the swing brake
when the pedal is depressed.
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