Manitowoc 14000 Service Maintenance Manual

Reference Only
INTRODUCTION 14000 SERVICE MANUAL
1-52
Published 09-05-14, Control # 226-02
Gantry Cylinders Lower
NOTE: Gantry back hitch pins must be disengaged before
raising or lowering gantry. See Back Hitch Pin
Cylinders topic in this section. The mast will lower
with gantry.
Move gantry cylinders toggle down and hold to lower gantry
(retract cylinders). An input voltage is sent to node 1
controller. Node 3 controller sends a 24 volt output to enable
gantry cylinders lower solenoid HS-25 and shifts valve to
lower position. Solenoid valve shifts to block tank port and
open port to low-pressure side of drum 1 pump. Node 4
controller sends a variable 0 to 24 volt output to enable low-
pressure side of drum 1 pump EDC.
Hydraulic fluid from low-pressure side of drum 1 pump flows
to gantry cylinders lower solenoid HS-25 of upper accessory
valve and through free-flow check valve sections on side B of
load equalizing valve. From equalizing valve, fluid enters
counterbalance valves and rod end of gantry cylinders,
retracting cylinder rod to lower the gantry.
Free-flow check valve sections on side A of counterbalance
valves block fluid exhausting from piston end of gantry
cylinders. Fluid passes through flow restrain sections of
counterbalance valve that has a relief setting of 3,500 psi
(240 bar). Counterbalance valves operate with a 5:1 pilot
ratio of the relief valve pressure, permitting valve to open
when fluid pressure in rod end of the cylinders is
approximately 700 psi (48 bar). Exhaust fluid from side A of
counterbalance valves combines and free-flow check valve
section on side A of load equalizing valve blocks the flow.
Hydraulic fluid then passes through flow restrain section of
valve that is preset at 4,000 psi (275 bar).
Load equalizing valve operates with a 1.5:1 pilot ratio of the
relief valve pressure. This permits valve to open when the
hydraulic pressure on side B of load equalizing valves is
approximately 2680 psi (185 bar). Restraining section on
side A of load equalizing valve opens, controlling fluid out of
both cylinders and ensuring cylinder actuation is balanced.
Hydraulic fluid exits through gantry valve section and returns
to tank.
When gantry is fully lowered, release gantry cylinders switch.
An input signal node 1 controller. Node 4 controller sends a
zero volt output signal to drum 1 pump EDC to de-stroke the
pump. Node 3 controller sends an output signal to shift
gantry cylinder lower solenoid HS-25 to center position.

Manitowoc 14000 Specifications

General

Brand	Manitowoc
Model	14000
Category	Construction Equipment
Language	English