Versalift VST-9000I-E100 User manual

Service and Installation
Manual
Time Manufacturing Co. 7601 Imperial Drive P.O. Box 20368 Waco, Texas 76702 Phone: [phone] Fax: [phone]
Aerial Device
ATTENTION:
THIS MANUAL CONTAINS CONFIDENTIAL INFORMATION
AND IS THE SOLE PROPERTY OF TIME MANUFACTURING CO.
CONTENTSARENOTTOBEDISCLOSED,COPIED,ORREPRODUCED
INANY MANNERWITHOUT THE EXPRESSED, WRITTENPERMISSION
OF TIME MANUFACTURING CO.
DO NOT ATTEMPT TO OPERATE THIS VERSALIFT UNTIL
YOU HAVE READ AND UNDERSTOOD ALL INFORMATION IN BOTH
OPERATOR’S AND SERVICE MANUALS, PROVIDED WITH EACH
VERSALIFT.
MANUAL PART NUMBER
39092-00
SERIAL NUMBER
Time Manufacturing Co. reserves the right to improve the design or change specifications at any time without notice.
11/14
PLEASE NOTE THE ANSI A92.2-2009 STANDARD AND THE MANUAL OF RESPONSIBILITIES CONTAINS
RECENTLY UPDATED INFORMATION. DEALERS, OWNERS, USERS, OPERATORS, LESSORS AND LESSEES MUST
ADHERE TO THESE UPDATED STANDARDS.
VST-9000I-E100
NG150001

MANUFACTURING COMPANY
OWNER’SWARRANTY
The Versalift Aerial Platform Lift is engineered and designed to perform as stated on
published specifications. Only quality material and workmanship are used in the
manufacture of this product. With proper installation, regular maintenance, and periodic
repair service, the equipment will provide excellent service.
Those parts of the Versalift that are manufactured by Time Manufacturing Company
are warranted for one full year from date of purchase. Structural components will carry
a lifetime warranty for defects in material and workmanship which existed at the time of
initial delivery, wear components are not covered by this statement. This warranty is
issued only to the original purchaser and promises that Time Manufacturing Company
manufactured products are free from defects in material and factory workmanship
when properly installed, serviced, and operated under normal conditions, according to
the manufacturer’s instructions.
Manufacturer’s obligation under this warranty is limited to correcting without charge at
its factory any part or parts thereof which shall be returned to its factory or one of its
Authorized Service Stations, transportation charges prepaid, within one year after being
put into service by the original user, and which upon examination shall disclose to the
Manufacturer’s satisfaction to have been originally defective. Correction of such defects
by repair to, or supplying of replacements for defective parts, shall constitute fulfillment
of all obligations to original user.
This warranty shall not apply to any of the Manufacturer’s products which must be
replaced because of normal wear, which have been subject to misuses, negligence or
accident, or which shall have been repaired or altered outside of the Manufacturer’s
factory (unless authorized by the Manufacturer in writing), products which have not
been maintained and operated in accordance with Time Manufacturing Company’s
operators, maintenance manuals and bulletins, products which are repaired without
using original Time Manufacturing Company parts. This limited warranty does not
cover transportation fees and/or consumables used for the repair.
Manufacturer shall not be liable for loss, damage, or expense directly or indirectly from
the use of its product or from any cause.
The above warranty supersedes and is in lieu of all other warranties, expressed or
implied, and of all other liabilities or obligations on part of Manufacturer. No person,
agent, or dealer is authorized to give any warranties on behalf of the Manufacturer or to
assume for the Manufacturer any other liability in connection with any of its products
unless made in writing and signed by an officer of the Manufacturer.

i
VERSALIFT VST-9000-I-E
TABLE OF CONTENTS
TABLE OF CONTENTS
Section 100- Introduction
Nomenclature.........................................................................................................................100-3
Section 101- Safety
Section 102- Theory of Operation
Mechanical System ................................................................................................................102-2
Hydraulic System....................................................................................................................102-2
Electrical System....................................................................................................................102-4
Options...................................................................................................................................102-5
Section 103- Service Procedures
Maintenance and Inspection...................................................................................................103-2
Prior to Placing Unit Into Service............................................................................................103-2
30 Days after “In Service” Date (one-time service) ................................................................103-5
Three Months or 250 Hours Service.......................................................................................103-5
Six Months or 500 Hours Service...........................................................................................103-7
Every year or 1500 Hours Service..........................................................................................103-8
Two Years or 3000 Hours Service..........................................................................................103-9
Torque Chart.........................................................................................................................103-11
Critical Fasteners and Welds................................................................................................103-12
Decal Placement ..................................................................................................................103-14
Checklist and Record ...........................................................................................................103-17
Adjustments..........................................................................................................................103-19
Cartridge Holding Valves......................................................................................................103-19
Leveling System Pressure....................................................................................................103-20
Rotation Motor Counterbalance Valves................................................................................103-21
Boom Actuation Speeds.......................................................................................................103-21
Hydraulic Oil Recommendations..........................................................................................103-22
Care of Fiberglass Booms....................................................................................................103-24
Trouble Shooting ..................................................................................................................103-24
Hydraulic Cylinder Repair.....................................................................................................103-26
Section 104- Installation
Introduction.............................................................................................................................104-2
Shipping and Handling ...........................................................................................................104-2
Fasteners................................................................................................................................104-3
Welding Specifications ...........................................................................................................104-3
Vehicle and Mounting Specifications......................................................................................104-3
Bolt Marking and Torque Chart...............................................................................................104-4
Installation and Pre-Delivery...................................................................................................104-5
Mounting Instructions .............................................................................................................104-5
Pre-Delivery Testing and Inspection.......................................................................................104-7
Section 105- Hydraulic Schematics
Hydraulic Schematic (JIC) .....................................................................................................105-2
Wiring Diagram Insulated ......................................................................................................105-3
Section 106- Parts and Assemblies
Parts Ordering and Product Support Information...................................................................106-3
As Built Options and Parts Index

BC-1280-2 Lower Boom Rest 107.....................................................................................
BC-1341-6 10 Ft Elevator Auto Latch Installation 108.......................................................
CA-1280-23 Capacity Option 1000 lb Jib & Winch w/ Lift Elevator 109...............................
CC-1280-11 Airline Installation Truguard on Lift Elevator 110.............................................
DE-1280-28 Decal Kit 4-Axis Upr Ctrls Truguard Single Tool w/Jib & Winch
on Single Lift Elevator 111.............
DE-1280-29 Decal Placement w/Jib & Winch on Single Arm Lift Elevator 112...................
DE-1341-5 Decal Placement for Single Arm Lift Elevator 113...........................................
DE-1400-15 Decal Kit 1 Set Out & Down 2 Spool w/Interlock 114......................................
E-1341-5 10 Ft Single Arm Lift Elevator Assembly 115..................................................
EP-1340-4 Emergency Power Insulated 12 VDC 116.......................................................
ET-1280-1 Electrical Test Bands 117................................................................................
FB-1500-6 Platforms 118..................................................................................................
HK-1280-49 Hydraulic Jib Truguard Hose Kit 119...............................................................
HK-1280-69 Lower Boom Hose Kit w/ Jib Winch on Single Lift Elevator 120......................
HK-1280-71 Inner Boom Hose Kit w/ Jib Winch on Single Lift Elevator 121.......................
HK-1280-72 Upper Control Hose Kit Truguard on Single Lift Elevator 122.........................
HK-1280-77 Single Arm Lift Elevator Hose Kit 10 Ft Elevator w/ Jib & Winch 123.............
HYD-1280-12 Tank Line Relief Installation 124.....................................................................
HYD-1280-14 Lower Control Console 125.............................................................................
HYD-1280-2 Cylinders 126...................................................................................................
HYD-1340-14 Chassis Hydraulics for Elevator 127................................................................
IB-1280-32 Inner Boom Assembly w/ Test Band Lift Elevator 128....................................
JW-1270-15 Jib & Winch 129...............................................................................................
KN-1280-1 Knuckle Assembly 130....................................................................................
LB-1280-4 Lower Boom Assembly 131.............................................................................
LT-1260-4 Lift Throttle Insulated 132................................................................................
MH-1280-19 Upper Boom Tip Rest 133...............................................................................
MH-1280-5 Upper Boom Rest Install - Turret Mounted 134...............................................
MH-1280-7 Upper Boom Rest Installation 135...................................................................
MH-1400-23 Out and Down Outrigger Mounting Hardware 136..........................................
MH-1400-23 Out and Down Outrigger Mounting Hardware 137..........................................
OB-1280-4 Outer Boom 138..............................................................................................
OR-1400-60 Out and Down Outrigger Assembly Track Vehicle 139...................................
OR-1400-60 Out and Down Outrigger Assembly Track Vehicle 140...................................
PS-1280-2 Platform Support Assembly For Jib And Winch 141........................................
PS-922 Platform Support 142.......................................................................................
RO-1280-3 Continuous Rotation 20 Pass Single Lift Elevator 143....................................
RP-1200-4 Rope Assembly 144........................................................................................
SC-1280-50 4-Axis RH Truguard Ipper Controls w/ Hydraulic Jib & Winch
Single Tool on Single Lift Elevator 145.............
SD-1200-13 Slope Indicator Installation 146.......................................................................
SS-60 Master Switch & Start/Stop 12V 147...............................................................
TT-1280-4 Turret Assembly Lift Elevator 148...................................................................
VK-1400-27 2 Sets Out & Down (4 Spool w/ Switch) 149...................................................
VK-1400-30 Dual Out and Down Interlock Kit 150..............................................................
VK-1400-32 12V Outrigger/Lower Boom Interlock 151.......................................................
Options Option List OptionList......................................................................................

TABLE OF CONTENTS

100-1
VERSALIFT VST-9000-I-E
INTRODUCTION
SECTION 100
INTRODUCTION

100-2
VERSALIFT VST-9000-I-E
INTRODUCTION
DANGER: THIS IS NOT MAINTENANCE
FREE EQUIPMENT.
NOTICE: THIS MANUAL IS A PERMANENT
PART OF THE VERSALIFTAERIAL DEVICE AND
MUST REMAIN WITH THE UNIT ALWAYS.
Time Manufacturing Company reserves the right
to improve the design or specifications at any time
without any obligation to incorporate new features
into products previously sold.
To better understand this manual, it is important that
theassociated personnel bethoroughly familiar with
the aerial lift. The following illustration identifies the
majorcomponents ofthe aerial lift. These terms are
used throughout the manual.
NOTE:As the aerial device users, you must read,
understand, and follow the instructions in this
manual and other manuals supplied with this
aerial lift unit.
This manual is furnished with your Versalift aerial
lift to provide practical and essential information
required maintaining the performance and life of
the Versalift. The scope of this manual includes
maintenance inspection, service and installation
information. Personnel responsible for maintaining,
inspectingandservicingtheaeriallift must be familiar
with this manual and the operator’s manual. A
working knowledge of all the information included
in both manuals is required.
In addition to, dealers, owners, operators, renters,
lessors and lessees are required to comply with the
requirements of the applicable section or sections
found in ANSI A92.2.
NOTE: For additional safety information
and required responsibilities refer to the
accompanying EMI Safety Manual and Manual
of Responsibilities.
Detailed information for the efficient operation of
the Versalift aerial device can be found in the
accompanying Operator’s Manual.
DANGER: THIS EQUIPMENT SHOULD
BE OPERATED AND SERVICED ONLY BY
COMPETENT PERSONNEL FAMILIAR WITH
GOODSAFETYPRACTICES. THISINSTRUCTION
IS WRITTEN FOR SUCH PERSONNEL AND
IS NOT INTENDED AS A SUBSTITUTE FOR
ADEQUATE TRAINING AND EXPERIENCE
IN SAFE PROCEDURES FOR THIS TYPE OF
EQUIPMENT.
DANGER: READ AND UNDERSTAND
THIS MANUAL BEFORE ATTEMPTING TO
SERVICE THIS AERIAL DEVICE.
INTRODUCTION
THIS MANUAL CONTAINS CONFIDENTIAL
INFORMATION AND IS SOLE PROPERTYOF
TIME MANUFACTURING,AND IS NOT TO BE
DISCLOSED, COPIED, OR REPRODUCED
WITHOUT EXPRESSED PERMISSION OF
TIME MANUFACTURING.

100-3
VERSALIFT VST-9000-I-E
INTRODUCTION
Figure 1.1 Model VST-9000-I-E Nomenclature

101-1
VERSALIFT SAFETY
SAFETY
SECTION 101
SAFETY

SAFETY
VERSALIFT SAFETY 101-2
Throughoutthis manual there are dangerandcaution
notes to warn of safety hazards while installing,
maintaining,orservicingtheVersalift. Anypersonnel
performing these procedures should be aware of
these concerns and responsibilities.
One hazard associated with installing or servicing
this machine is lifting heavy objects. This is true
whether the lifting is being done manually or
mechanically. The weight, length, and other
characteristics of the booms, pedestal, turret, and
outriggers make it imperative that care be taken to
balanceandsupportthem adequately when they are
lifted. Care must be taken to balance these items
and to keep personnel clear when lifting.
Never clean, oil, or adjust a machine while it is in
motion. Special care must be used while the guards
orprotective covers areremoved. The moving parts
of the lift will cause crushing injuries if precautions
arenot taken. Theguards and protectivecoversmust
bereplacedassoon as the service workiscomplete.
Hydraulic oil is flammable so contact between
hydraulicoiland sources of high heatoropen flames
must be avoided. Contact with hot hydraulic oil may
cause serious burns which require immediate
medical attention.
Failure to relieve pressure before disconnecting of
the hydraulic hoses or fittings may result in a high
pressure hydraulic oil spray. This spray or mist can
puncture and become embedded beneath the skin
or contaminate the eyes. Relieve pressure by
activatingthecontrolvalve while the hydraulicpower
source is off or disengaged. Loosen connections
slowly to make certain pressure is relieved.
Astabilitytest,percurrentANSIA92.2 requirements,
must be performed on the unit after it is mounted.
This must be done before anyone operates the lift
from the platform.
After servicing any portion of the hydraulic system,
extend and retract all of the hydraulic cylinders
several times to force any trapped air from the
system. Neveroperate the liftfrom theplatformuntil
this has been accomplished.
Warning and instructional decals are installed at
numerouslocations ontheaeriallifttowarnpersonnel
ofthepotentialhazardsduring the use and operation
of the Versalift aerial lift. If any decals are defaced,
illegible, or lost they must be replaced immediately.
No manual can address every conceivable hazard
whileinstalling,maintaining,orservicingan aerial lift.
SAFETY
The prevention of accidents is dependent on good
judgement and common sense on the part of the
service personnel.

102-1
VERSALIFT VST-9000-I-E
THEORY OF OPERATION
SECTION 102
THEORY OF OPERATION

102-2
VERSALIFT VST-9000-I-E
THEORY OF OPERATION
THEORY OF OPERATION
MECHANICAL SYSTEM
Several mechanical systems are utilized in the
operation of the Versalift aerial lift. They are
described in detail below.
OUT AND DOWN OUTRIGGERS - The outriggers
consist of an outrigger frame attached to the
subframe with two rectangular inner and outer
tubes. A leveling jack leg with a pivot foot pad is
attached to one end of the outrigger inner tube.
The jacks are used to level and stabilize the lift
during operation. Adouble acting hydraulic cylinder
is housed within the outriggers and jack legs frames
which is attached to the larger tube near the top
and to the smaller tube near the bottom.
As the outrigger hydraulic cylinder is extended the
inner tube telescopes out and away from the center
of the aerial lift chassis. As the jack leg hydraulic
cylinder is extended, it lowers the leg inner tube
to contact the ground. Sufficient extension is
provided to allow the outrigger legs to contact the
ground and elevate the chassis slightly. The out
and down outriggers greatly increase the vehicles
resistance to overturning since the tipping point is
moved further away from the center of gravity.
ROTATION - The turret, lower boom, upper boom,
and platform of the aerial lift, supported by a shear-
ball bearing, rotate about a vertical centerline of the
pedestal. This bearing consists of two concentric
rings. The inner ring is attached to the turret and
has a groove around the outer diameter. The outer
ring is attached to the pedestal and has a groove
around the inner diameter. Spherical rollers or balls
are trapped between the two rings in the grooves.
The balls allow rotation of the inner ring and the
attachment components relative to the stationary
outer ring. This motion is controlled by a gear
train that is driven by a hydraulic motor. Gear
teeth on the outside diameter of the outer bearing
ring engage a worm supported on the turret. As
the worm rotates, the turret rotates relative to the
outer bearing ring. The hydraulic motor actuates
the worm. Smooth and controlled rotational
movements of the turret, lower boom, upper boom,
and platform are provided.
LOWER BOOM - The lower boom pivots about a
horizontal centerline on the turret. A double-acting
hydraulic cylinder attached to the turret and lower
boom actuates the lower boom. With the cylinder
fully retracted, the lower boom is horizontal. As
the cylinder extends; the lower boom raises a
compensation link maintains the upper boom at a
constant angle, relative to the ground as the lower
boom raises or lowers, and allows smooth and
direct platform movements as the lower boom is
being raised.
UPPER BOOM - The upper boom pivots about a
horizontalcenterline at the knuckle.The telescoping
upper boom articulates, from 25° below horizontal
to 75° above horizontal.
ELEVATOR ARM - The lift elevator arm is actuated
by a double acting cylinder. With the cylinder
retracted, the arm is horizontal. As the cylinder
extends, the arm rotates to its raised position.
Relief valves on the cylinders prevent excessive
forces on the arm when stowed. Compensating
links keep the lift rotation bearing level throughout
the full range of elevator motion.
HYDRAULIC SYSTEM
The hydraulic schematics will aid in understanding
the hydraulic system. Refer to “Hydraulic
Schematics” section. Descriptions of the major
components in the hydraulic system are given
below.
PUMP - The PTO driven pump delivers about 10
gpm(37.85lpm). Whentrouble-shootingahydraulic
circuit it is helpful to remember that a pump does
not produce pressure. It only produces fluid flow;
resistance to fluid flow produces pressure.
OIL RESERVOIR - The bulkhead hydraulic oil
reservoir holds 50 gallons (227 l). Oil is drawn out
from and returned to the bottom of the reservoir.
This prevents entrainment of air in the hydraulic oil
and allows the return filter to be changed without
draining the reservoir. The reservoir also includes
a baffle to minimize the entrainment of air in the oil.
FILTRATION - The return line filter is located on the
top of the oil reservoir and the suction strainer is
located in the reservoir, attached to the bottom of
tank. The return line filter has a 10 micron rating.
The suction screen has a 100 mesh (149-micron)
rating,and can beremoved and cleaned. Oil leaves
the tank, passing through the suction strainer on
the way to the hydraulic pump. All of the oil passes
through the return line filter on its way to the tank.
GROUND CONTROLS - The ground controls
consist of a selector valve, four-way control valves,
and optional controls for a ground-level tool circuit.
The selector valve consists of a two-position spool
valve that directs hydraulic oil flow either to the lift
or to the other ground controls.

102-3
VERSALIFT VST-9000-I-E
THEORY OF OPERATION
The outrigger controls consist of two, four-way
control valves connected in series. A relief valve
is integral to these control valves. Hydraulic oil is
directed to either end of a double-acting hydraulic
cylinder, which extends or retracts the outriggers.
A lock valve or double pilot operated check valve
is mounted on each outrigger cylinder, blocking
undesired flow out of each end. When the four-way
control valve is actuated, pressure is applied to one
end of the cylinder and to a pilot piston that opens
the check valve allowing flow out of the other end.
Flow now extends or retracts the outrigger cylinder
as desired. A thermal relief valve is incorporated
into the lock valve that allows excessive pressure
created by thermal expansion to bypass the check
valve.
The optional tool circuit control includes a two-
position selector valve. Ground-level hydraulic
tools can be operated when the ground controls are
engaged and the tool selector is actuated.
When the ground controls are selected, oil will
circulate through the control valves and back to
the reservoir because they are open center valves.
Open-Center valves help warm-up the hydraulic oil
in cold weather.
ROTARY JOINT -Arotary joint is mounted between
the turret and pedestal, To provide hydraulic flow
to the lift and allows continuous rotation of the lift.
The rotary joint consists of a cylindrical case, which
houses a spool. The case is bolted to the pedestal
and the spool is fastened to the turret.
Oil from the pump enters port 2 of the spool, flows
up a drilled passage in the spool, and into a groove
which encircles the surface of the spool. Oil flows
along the groove until it comes to the outlet port 2
in the case, wherever it is at that particular time.
Because the case outlet moves along the groove
as the lift rotates, oil flows uninterrupted out of the
case port. Return oil flows through port 1 and 3 of
thecase,alongthegrooveincontactwithrespective
port and then out each respective port of the spool
on its way back to the oil reservoir. Since all of the
relative motion takes place between the spool and
the case, continuous rotation is possible.
LOWER CONTROLS - The lower controls are
located on the console at the deck. The platform
override control is the first section of the control
valve. When this control is selected oil is diverted
either to the upper controls or allowed to flow to
the second, third, fourth, fifth, sixth and seventh
sections which control the lower boom, upper
boom, rotation, winch, platform leveling, lower
arm elevator and upper arm elevator functions
respectively. Oil is available to these sections only
when the lower controls are selected.
UPPER CONTROLS - The single stick upper
control consists of a seven-section control valve,
selector valve, and a tool/accessory valve. Asingle
selector valve diverts oil from the control valve to
the reservoir. This valve is used as the emergency
stop valve.
The seven-section control valve is used to operate
unit functions. The first spool of this valve is used
for platform leveling. The second spool is used for
platform rotation. The third spool is used for the
lower boom function. A simple lever starts these
three functions. The fifth, sixth and seventh spools
operate the boom functions through a specially
developed single stick package.
The fourth spool diverts the flow of oil, to the fifth,
sixth, and seventh boom function spools, or to the
toolcircuit. Withthesafetytriggerreleased,oilflows
to the tool/accessory valve. With the safety trigger
activated, oil flows to the boom functions spools.
The tool/accessory valve operates jib extend, jib
tilt, winch, and tools. When the tool power lever is
“ON” oil flows to the tool, otherwise the oil returns
to tank.
BOOM AND ARM CYLINDERS AND HOLDING
VALVES - When the valve controlling the oil flow to
the cylinders is actuated, the oil leaves the control
valve assembly and flows to the holding valve.
Where it enters three passages. A piston, spring-
loaded against its seat blocks one passage. The
incoming oil is on the same side as the spring. This
causesthepistontobepressedeventighter against
the seat, effectively blocking the passage. The oil
then flows through the other passage, which has
a spring-loaded check valve in it. The oil pushes
the check valve off its seat, flows out of the holding
valve, and into the hydraulic cylinder.
The hydraulic cylinders are double acting, meaning
both ends of the cylinder can be pressurized. In
orderfortheincomingoiltomovethecylinderpiston,
oil on the other side of the cylinder piston must be
able to escape from the hydraulic cylinder. The oil
cannot escape because the other holding valve is
blocking it. The passages in this holding valve are
identical to the ones described above, however,
the oil is trying to flow through the passages in the
opposite direction. The oil meets the piston and
the check valve again, both identical to those in the
holding valve. However, the oil is on the backside

102-4
VERSALIFT VST-9000-I-E
THEORY OF OPERATION
TRUCK IGNITION SWITCH - The current used
when operating the start/stop control comes from
the truck ignition system. The key must be in the
ignition and turned to the “Run” position before
current is available to operate the electrical system.
TOGGLE SWITCH - The single-pole, two-position
toggle switch is mounted on the truck dash board.
RED DASH LIGHT - The red 12 volt dash light
indicates when the master control system is
activated.
OPERATION THEORY OF THE MASTER
CONTROL
The master control provides a toggle switch on the
truck dash to energize and de-energize the start/
stop system.
With the master control toggle switch activated and
the ignition switch in the “Run” position, current
flows from the ignition switch through a 20 amp
fuse to terminal 2 on the toggle switch. Through
the toggle switch current flows from terminal 2 to
terminal 3; from there current flows to terminal 7
on the terminal block, located in the ELECTRICAL
BOX ASSEMBLY. In addition, current flows from
terminal 3 on the toggle switch to the dash light.
The dash light will illuminate as current flows
through it to a ground.
With the master control toggle switch deactivated,
there is no electrical current flow to the dash light or
terminal 7, on the terminal block. The truck ignition
system will function normally.
START/STOP CONTROL COMPONENTS
Dash Push-button Control - This is a spring-
loaded, push-button control that can be used by
ground personnel to start or stop the truck engine
when the master control system is activated.
Start Relay - The 12 volt, single-pole, start relay
is mounted in the electrical box and is normally
in the open position. When activated, the start
relay connects the truck battery to the truck starter
solenoid.
Stop Relay - The single-pole stop relay is mounted
in the truck engine compartment and is normally in
theclosedposition. Whenthestop relayisactivated
the ignition circuit and the start relay control circuit
are broken and the engine stops.
of them now. It is on the same side of the check
valve as it’s spring.
The combination of the oil and the spring holds
the check valve firmly on its seat, blocking this
passage. The oil also pushes against the backside
of the piston, the side opposite the spring. The oil
tries to push the piston off its seat by compressing
the spring. Normally, the load-induced pressure
of the trapped oil is not sufficient to overpower the
spring and push the piston off its seat. Thus, the
oil remains trapped. This is what produces the
holding action, which prevents the booms from
creeping down or free falling should hydraulic lines
be damaged.
To release this trapped oil, hydraulic oil pressure
must be applied to the pilot piston to push it off
its seat. This pilot pressure is obtained from the
third passage for incoming oil. The combination
of the pilot pressure and the trapped oil pressure
overpowers the spring, pushes the piston off its
seat, and allows a controlled flow of oil out of the
cylinder returning to the control valve and back into
the reservoir.
As mentioned before, normal load induced
pressures are not adequate to overpower the spring
that acts on the piston. However, excessively
high pressures such as those generated from the
thermal expansion of the oil will open the piston
sufficiently to relieve this pressure.
The retract pressure of the upper and lower boom
cylinder is limited to 1000 psi, by an integral relief
valve, to minimize forces if the booms are over-
stowed.
HYDRAULIC PLATFORM LEVELING - The
hydraulic platform leveling system consists of a
master/slave cylinder combination with connecting
hoses. As the outer/inner boom is raised or
lowered hydraulic oil is forced from the master
cylinder through the hydraulic lines to actuate the
slave cylinder. Counterbalance valves on the slave
cylinder prevent platform movement in the event of
hydraulic leveling hose failure. Leveling controls
are included at the upper and lower controls for
leveling adjustment.
ELECTRICAL SYSTEM
The electrical schematics will aid in understanding
the electrical system. Refer to the specific option
schematics. Descriptions of the major components
in the electrical system are given below.

102-5
VERSALIFT VST-9000-I-E
THEORY OF OPERATION
Ignition Relay - The 12 volt, double-pole, double-
throw, latching ignition relay is mounted in the
electrical box. One set of points is in the start circuit
and the other set of points is in the ignition circuit.
Pressure Switch and Air Cylinder - The pressure
switchis mounted onthe turret wing andconnected,
by an air line, to an air cylinder mounted on the
platform control panel. When the air cylinder is
operated,airpressureis produced and the electrical
contacts in the pressure switch close. The truck
engine is started or stopped depending on the
position of the ignition relay contacts.
Toggle Switch (Lower Controls) - A single-pole,
three position, momentary toggle switch is mounted
on the lower control cover. The truck engine is
started or stopped depending on the position of the
toggle switch.
OPERATION THEORY OF START/STOP
CIRCUITS
Start/Stop Circuit -When the master controltoggle
switch is activated and the ignition switch is in the
“on” position, current flows to terminal 7 on the
terminal block. Current from terminal 7 flows to the
ignition relay. The ignition relay supplies current to
the start or stop relay depending upon the latching
position. The latching position is toggled between
the start and stop position each time one of the
start/stop switches is operated.
In order for the start system to operate, the ignition
relay must be latched in the start position and one
of the start/stop switches must be held in the start
position. With the start relay energized, current
from the battery flows to the starter solenoid.
To activate the stop system, the ignition relay must
be latched in its stop position and one of the start/
stop switches must be held in the stop position.
With the stop relay energized, the ignition circuit
and the start relay control circuit are broken and the
engine stops.
MANUAL ENGINE THROTTLE CONTROL
The throttle control electrical schematics will aid in
understanding the electrical system. The manual
throttle control components and their function are
described in detail below.
Truck Ignition Switch - All current used for
operating the throttle control system comes from
the truck ignition switch.
Throttle-control Relay - This relay is a 12-volt,
double pole, double-throw, latching relay mounted
in the electrical box.
Pressure Switch And Air Cylinder - The pressure
switch is mounted on the turret wing and the air
cylinder is mounted on the platform control panel.
A small air line connects the two components
together. When the air cylinder is operated, air
in the line is compressed. When adequate air
pressure is produced, the electrical contacts in the
pressure switch close and the electrical solenoid on
the engine is activated or deactivated, depending
on the position of the latching relay.
ThrottleActuator -Thethrottleactuatorismounted
in the engine compartment. It is activated by an
electrical signal from the throttle control latching
relay. Gas and diesel engine models use an
electrical solenoid actuator.
Toggle Switch (Lower Controls) - The toggle
switchis atwo-position, maintained switch mounted
on the lower control cover. The throttle control relay
is energized when the toggle switch is operated.
OPTIONS
EMERGENCY POWER
The emergency power option wiring schematic
will aid in understanding the emergency power
system. Refer to the specific option schematics.
The electrical components and their functions are
described in detail below.
Motor - The motor is a 12 volt DC motor that can
operate an auxiliary hydraulic pump in the event
that the main pump cannot be used. Power to
operate the motor is obtained from the truck battery.
Solenoid - The power solenoid is mounted on the
motor and is used to complete the circuit between
the truck battery and the motor. The control coil of
the solenoid does not have an internal ground for
completionofthecontrol circuit. Ground connection
is controlled by a control in the platform.
Pressure Switch And Air Cylinder - The air
cylinder and pressure switch are identical to the
ones used for the start/stop system. Refer to the
start/stop system theory for a description of how
they work. Operation of these two components
completes the solenoid control circuit.
Toggle Switch (LowerControls)- Thesingle-pole,

102-6
VERSALIFT VST-9000-I-E
THEORY OF OPERATION
Therearetwocircuitsthatcanenergizethesolenoid.
One circuit is through the lower boom-limit switch
and the other circuit is through the outrigger limit-
switches and toggle switch.
With the boom stored and the outriggers retracted,
theboomlimit switch is open and both outrigger limit
switches are open. Therefore, both circuits to the
solenoid are open and the solenoid is de-energized,
hydraulic flow is directed to the outrigger controls.
Note that under these conditions, the toggle switch
has no effect on the solenoid which prevents
operating the lift without extending the outriggers.
When the outriggers are extended to ground, the
outrigger limit switches close, completing the circuit
to the toggle switch.
If the toggle switch is open, the solenoid remains
de-energized. Closing the toggle switch energizes
the solenoid, thereby directing hydraulic flow to the
lift controls.
Raising the lower boom off the boom rest closes the
boom limit switch. This completes a second circuit
to the solenoid.
If the toggle switch is now opened or if one outrigger
raises off the ground, the solenoid valve remains
energized through the boom limit switch and
hydraulic flow remains directed to the lift controls.
If the optional override switch is installed, the
solenoid can be de-energized by opening the
switch. This directs hydraulic flow to the outrigger
controls regardless of the other system conditions.
two-position, maintained, toggle switch is mounted
on the turret control valve cover. The emergency
power solenoid is energized or de-energized
depending on the position of the toggle switch.
OPERATION
Control Circuit - Power for the control circuit
comes from the “on” terminal of the ignition switch.
This means that the key must be in the ignition and
turned on before the system will operate. Current
flow is from the “on” terminal of the ignition switch,
through the solenoid coil, and through pressure
switch to ground.
OUTRIGGER/BOOM INTERLOCK
The outrigger/boom interlock option is a safety
feature designed to prevent the lift from being
operated until the outriggers are properly extended.
The interlock also prevents the outriggers from
being retracted before the lift is properly stored.
Refer to the “Outrigger/Boom Interlock Installation”
in “Parts & Assemblies” Section. for installation
drawing. The outrigger/boom interlock components
and their functions are described below.
Outrigger Limit Switch - One switch is mounted
at each outrigger upper cylinder pin. When the
outrigger contacts the ground, the upper pin moves
upward actuating the switch.
Toggle Switch - This switch is located near the
outriggercontrolvalves. It is used to select between
lift controls and outrigger controls, provided the
interlock requirements are met.
Boom Limit Switch - This switch is mounted at
the boom rest to indicate the position of the lower
boom. The switch is open when the boom is stored.
Solenoid Valve - This valve directs the hydraulic
flow from the pump to either the lift controls or the
outrigger controls. When the solenoid is energized,
hydraulic flow is directed to the lift controls.
Override Switch (Not Included) - If required, this
switch may be installed as shown in the schematic.
It allows the interlock to be temporarily defeated.
Continuous actuation is required to accomplish this.
OPERATION THEORY OF OUTRIGGER/BOOM
INTERLOCK
The outrigger/boom interlock system operates by
energizing or de-energizing the solenoid valve.

103-1
VERSALIFT VST-9000-I-E
SERVICE PROCEDURES
SECTION 103
SERVICE PROCEDURES