Dhollandia DH-R Quick start guide

Order ref: xxx Doc: TECH_US technical guide DHR_US EN_2021 Rev: 0Date: SEPTEMBER 23, 2021
DH-R*
TECHNICAL GUIDE
Read the manual in its entirety before operating the liftgate
Keep this manual in the vehicle cab, as reference for the driver and liftgate operator
Manufacturer:
DHOLLANDIA US, L.L.C.
E-mail : [email protected]
270 Southridge Parkway
Bessemer City North Carolina, 28016
website : www.dhollandia.com

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DHOLLANDIA
TABLE OF CONTENTS
1UNDERSTANDING SAFETY AND WARNING SIGNS...................................................................................................................... 2
2INTRODUCTION AND DISCLAIMERS ............................................................................................................................................. 3
3SAFETY PRECAUTIONS FOR OPERATION ................................................................................................................................... 4
4LIFTGATE TERMINOLOGY .............................................................................................................................................................. 4
4.1 Liftgate ...................................................................................................................................................................................... 5
4.2 Power pack ............................................................................................................................................................................... 7
5ELECTRICAL BASICS AND CONTROLS ....................................................................................................................................... 10
5.1 E2051 connection block .......................................................................................................................................................... 10
5.2 Main control (OAE015.PR –E0832.B).................................................................................................................................... 11
5.3 Extra control (OAE001 –E0783.H.S)...................................................................................................................................... 12
5.4 New series cabin switch (OAE510.15 –E0393.S.15) ............................................................................................................. 13
5.5 Cabin switch (OAE503.1 –E0667.12)..................................................................................................................................... 14
6SCHEMATICS ................................................................................................................................................................................. 15
6.1 General schematic symbols and legend.................................................................................................................................. 15
6.2 Power down schematics.......................................................................................................................................................... 16
6.3 Gravity down schematics ........................................................................................................................................................ 19
7TROUBLESHOOTING..................................................................................................................................................................... 22
7.1 Checking batteries................................................................................................................................................................... 22
7.2 Checking oil............................................................................................................................................................................. 23
7.3 Motor fails to run...................................................................................................................................................................... 24
7.4 Liftgate will not lift.................................................................................................................................................................... 26
7.5 Liftgate will not lift the rated capacity....................................................................................................................................... 27
7.6 Liftgate will not lower............................................................................................................................................................... 28
7.7 Liftgate drifts down .................................................................................................................................................................. 29
7.8 General platform issues .......................................................................................................................................................... 30
8CONTACT INFORMATION ............................................................................................................................................................. 32
9APPENDIX....................................................................................................................................................................................... 33
9.1 Meaning of the safety and warning signs................................................................................................................................ 33
9.2 Prescribed torque values for bolts and nuts ............................................................................................................................ 35
9.3 Electric and hydraulic requirements ........................................................................................................................................ 36
9.4 Connections to the main external control box type 1............................................................................................................... 38
9.6 End note.................................................................................................................................................................................. 42
9.7 Basic wiring diagrams ............................................................................................................................................................. 42
9.8 Checklist for preventative maintenance and repair ................................................................................................................. 42

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DHOLLANDIA
1UNDERSTANDING SAFETY AND WARNING SIGNS
•Many safety signs and symbols used in this manual are based on international standards, others refer to specific situations or actions.
•Consult appendix 9.1 on page 33 for an overview of signs and symbols used in DHOLLANDIA manuals, and their meaning. Make
sure you understand these signs and symbols prior to starting the installation.
•Please take special notice of the following signs used in the manual. They indicate the likelihood and severity of a potential injury if
a person fails to follow the instructions presented on the safety sign.
DANGER: indicates an imminently hazardous situation which, if not avoided, will result in death or
serious injury. [white letters on red background]
WARNING: indicates a potentially hazardous situation which, if not avoided, could result in death or
serious injury. [black letters on orange background]
CAUTION: indicates a potentially hazardous situation which, if not avoided, could result in minor or
moderate injury. [black letters on yellow background]
NOTICE: is used to address practices not related to physical injury. [white letters on blue background]
SAFETY INSTRUCTIONS: indicate general instructions relative to safe work practices, reminders of
proper safety procedures, or the location of safety equipment. [white letters on green background]
SAFETY ALERT SYMBOL: is used to alert the user to potential hazards. All safety messages that
accompany this sign shall be obeyed to avoid possible harm. [free-standing, or on back-ground
colours red, orange, yellow or black]
WARNING
•Failure to understand and to follow the instructions in this manual can put the operator and any bystanders at great risk of serious
bodily injury and death.
•Prior to operating the liftgate, make sure you understand the safety and warning signs used, and read them in conjunction with
the instructions in this manual.
•If in doubt, DO NOT operate the liftgate. Contact your national DHOLLANDIA distributor. See page 30 for contact info.
NOTICE
SAFETY
INSTRUCTIONS

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DHOLLANDIA
2INTRODUCTION AND DISCLAIMERS
•This manual provides you with the information necessary for the troubleshooting of the DH-R* series Fold-Away lifts.
•It contains general instructions applicable to the most common types of trucks and trailers. Possibly, specific issues particular to your
case are not adequately covered by this manual. If in doubt, contact your national DHOLLANDIA distributor for further assistance
prior to continuing.
•DHOLLANDIA liftgates are regularly adapted to new vehicle and chassis developments and specialized customer requirements.
Therefore, DHOLLANDIA reserves the right to alter product specifications without prior notice. Such modifications might not have
been included at the time this manual was printed.
NOTICE
•Please confirm you have reviewed the most up-to-date version of this manual prior to operation of the associated DHOLLANDIA
liftgate. See below for instructions to download the latest version of the manual.
•It is the sole responsibility of the installer(s) to follow best workshop practices for safety and craftsmanship and to use good
common sense.
The latest version of all manuals can also be downloaded from the DHOLLANDIA website:
www.dhollandia.com → Country & language selection → Downloads → … select required manual
•Take notice of the following important disclaimers:
DISCLAIMERS
•DHOLLANDIA disclaims liability for any personal injury, death, or property damage that results from operating a liftgate that has
been modified from the original design, without written approval from the manufacturer.
•DHOLLANDIA disclaims liability for any personal injury, death, or property damage that results from improper use of the liftgate
or negligence to apply the precautions and instructions of the operation manual.
•DHOLLANDIA disclaims liability for any personal injury, death, or property damage that results from incorrect of negligent
installation.
•There are no warranties, express or implied, including the warranty of merchantability or a warranty of fitness for a particular
purpose extending beyond that set forth in this manual.
WARNING
•Improper installation can cause damage to the liftgate, can reduce its durability and reliability, and can put the operator and
bystanders at great risk of serious bodily injury and death in many ways.
•It is therefore essential that the liftgates are installed with proper care, in compliance with the installation instructions of this manual
and the fitting and body building instructions of the vehicle manufacturer.
•In case of doubt, ALWAYS contact your national DHOLLANDIA distributor for further advice, prior to continuing.

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3SAFETY PRECAUTIONS FOR OPERATION
•It is essential that the installers understand and apply the safety instructions and precautions contained in the
OPERATION MANUAL issued with the liftgate.
•Therefore, make sure you consult the OPERATION MANUAL prior to installing or operating the liftgate.
4LIFTGATE TERMINOLOGY
•DHOLLANDIA liftgates are developed and manufactured using state-of-the-art technology, high quality materials and components
and highly skilled workmanship.
•The DH-R… series comprises of a range of fold-away liftgates, designed for a wide variety of trucks, trailers and semi-trailers, and
is available with lift capacities ranging from 2,200 to 5,500 lbs.
•In its travel position, the foldable platform of the liftgate is safely stowed underneath the vehicle body. To deploy the liftgate, the
platform and lifting mechanism are lowered to the ground by means of the electric controls. Then the platform main section and flip-
over point are unfolded manually.
•Main details and terminology: see below:
WARNING
•Improper use of the liftgate will put the operator and other parties at great risk of serious bodily injury and death.
•To reduce the risk of serious bodily injury to the operator and any bystanders, the use of the liftgate is restricted to skilled operators,
who have been properly trained, and who know and understand the full content of the operation manual.
•To reduce the risk of serious bodily injury or death, the operator must comply with all safety instructions and warning labels in the
operation manual before and while operating the liftgate.
•Please confirm you have reviewed the most up-to-date version of this manual prior to installation and operation of the associated
liftgate.

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4.1 LIFTGATE
LIFTGATE TERMINOLOGY
See figure on next page for parts corresponding to numbers in this table
#
Description
1
Lift frame: mounted in a fixed position under the vehicle chassis. It bears the platform and its load via connection to the lift arms
and hydraulic cylinders.
2
Mounting plates: used to mount the lift frame to the vehicle chassis.
3
Foldable platform: carries the load during loading / unloading, lifting / lowering. Consists of a platform main section and a flip-
over point.
3a
Platform main section: inboard section of the foldable platform. Manufactured from steel or lightweight aluminium, with a
permanent non-slip working surface.
3b
Flip-over point: foldable, outboard section of the platform. Manufactured from lightweight aluminium.
4
Lift arms L+R: actuated by the hydraulic lift cylinders, used to LIFT / LOWER the platform and its load.
5
Lift cylinders L+R: 1 or 2 hydraulic cylinders used to LIFT / LOWER the lift arms, the platform and its load.
6
Parallel arms L+R: 2 parallel arms, supporting the platform while it travels up and down.
7
Hydraulic pump unit: contains the electric motor driving the hydraulic pump, the oil tank, and the control valves.
8
Toggle-switch control: easy-to-use controls to LIFT / LOWER the platform, mostly mounted in fixed position at the side of the
vehicle body, or on the rear post of the body.
9
Bumper bar: under run protection device, certified conformance to CE legislation.
10
Center point of maximum load: point up to which the maximum rated capacity of the liftgate is valid. Beyond that point, the
maximum safe working load diminishes according to the applicable load charts.
11
Platform opener: arm with roller(s) mounted on the lift frame, assisting the deployment of the platform from its travel position
to the work position, then back to its travel position.
12
Extension plate: heavy duty steel extension mounted to the rear sill of the vehicle floor, with a permanent non-slip surface.
13
Side steps L + R: steps mounted to the side of the extension floor to help the driver climb into the vehicle from the side. The
side steps incorporate rubber dock bumpers [13a]; support channels [13b] and diagonal braces [13c].
13a
Dock bumpers: rubber buffers mounted on the rear face of the side steps, to reduce impact damage when the vehicle is backing
into a loading dock.
13b
Support channels: steel channels welded to the underside of the vehicle body (to the rear sill and support cross members
underneath the vehicle floor).
13c
Diagonal braces: steel profiles linking the side steps and dock bumpers with the support channels welded to the underside of
the vehicle body. The construction with support channels and diagonal braces aims to distribute the forces of a dock impact
over the rear sill and support cross members of the vehicle body and avoid damage as much as possible.

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DHOLLANDIA
1
2
3
4
5
6
7
8
9
2
3a
3b
10
11
12
13
13a
13b
13c
9

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DHOLLANDIA
4.2 POWER PACK
POWER PACK TERMINOLOGY
See figure on next page for parts corresponding to numbers in this table
#
Description
1
Connection block: main junction for connecting the controls of the liftgate.
2
Motor relay: solenoid responsible for starting the electric motor.
3
Electric motor: 12V motor running directly off battery power that drives the hydraulic pump.
4
Thermal contact: protects the motor from overheating, acts as a ground for the motor relay.
5
Logic block: manifold resposible for directing hydraulic flow to operate various liftgate functions.
6
Flow restrictor: restricts hydraulic flow as fluid returns to the reservoir.
7
Pressure gauge port: port to connect a pressure gauge to measure system hydraulic pressure.
8
Pressure check valve: responsible for keeping the hydraulic pressure in the system at a safe level.
9
Reservoir: contains hydraulic fluid for the liftgate.
10
Switching plunger: valve that separates high pressure from low pressure inside the logic block.
11
Hydraulic pump: coupled to the electric motor. Pumps fluid from the reservoir into the logic block.
(This component is located inside the reservoir).
12
S4 Switching valve: logic block for power down functionality (NOT PRESENT ON GRAVITY DOWN LIFTGATES).
13
Power down valve: responsible for switching the direction of hydraulic fluid to enable power down functionality.

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9
1
2
4
3
7
8
10
5
11

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NOTICE
•Items 12 and 13 are NOT present on gravity down models, only power down.
•Items marked with red squares are responsible for LIFT, items with blue diamonds are responsible for LOWER.
5
13
12
6

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DHOLLANDIA
5ELECTRICAL BASICS AND CONTROLS
•This chapter will explain the electrical basics of DHOLLANDIA DH-R* series liftgates.
5.1 E2051 CONNECTION BLOCK
•The orange connection block acts as a junction between the controls and the components of the liftgate.
•In the image above, “MC” and “EC” stand for Main Control and Extra Control, respectively. This is where the source leads for your
controls can be connected to power the various liftgate functions.
•As seen above for column “O”, there are 4 blade connections available on each “row”. These blades are all connected together in
parallel. This principle is true for all rows, “+” through “R” (left to right on the connection block).
•Similarly, the two horizontal (pink) rows at the top of the connection block all act as GROUND and tie into the “-“ negative stud on
the electric motor.
•The table below shows the typical functionality of this block for DHOLLANDIA DH-R* series liftgates:
Row
Function
R
Activates the motor relay, which in turn powers the electric motor.
H
Activates the S4 switching valve (NOT PRESENT ON GRAVITY DOWN LIFTGATES).
D
Energizes the safety valves located on the lift cylinder(s).
+
Main 12V source from vehicle batteries to power controls and components
-
Ground

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5.2 MAIN CONTROL (OAE015.PR –E0832.B)
•The primary control for the DH-R* series liftgates is shown wired in default configuration below:
NOTE:
BN and WH leads are switched for gravity down units.

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5.3 EXTRA CONTROL (OAE001 –E0783.H.S)
•The most popular secondary control for the DH-R* series liftgates is shown wired in the configuration below:

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5.4 NEW SERIES CABIN SWITCH (OAE510.15 –E0393.S.15)
•The newer generation cabin switch control for the DH-R* series liftgates is shown wired in the configuration below:

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DHOLLANDIA
5.5 CABIN SWITCH (OAE503.1 –E0667.12)
•The older generation cabin switch control for the DH-R* series liftgates is shown wired in the configuration below:

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DHOLLANDIA
6SCHEMATICS
•This chapter will outline both power down and gravity down schematics for DHOLLANDIA DH-R* series liftgates.
•For the sake of simplicity, only the primary control (OAE015.PR / E0832.B) will be shown.
•To troubleshoot other configurations, please refer to the previous chapters, or see contact information on page LINK.
6.1 GENERAL SCHEMATIC SYMBOLS AND LEGEND
•This short chapter outlines important schematic symbols and parts helpful in the viewing and understanding of the schematics to
follow. Each item is given along with name and description, below:
Item
Name
Description
Hydraulic Action
Shows the components and rows on the connection
block that are used for each function, LIFT and
LOWER.
Reservoir
Pump
Motor
Motor Relay
Shows the main hydraulic / electrical power system
used by the liftgate as one, condensed unit.
Pressure Gauge Port
Port available to measure working pressure of the
hydraulic system.
Pressure Relief Valve
Allows hydraulic fluid to return to the reservoir if the
maximum load capacity of the gate is exceeded.
No Return Check Valve
Braking Valve
The check valve allows hydraulic fluid to flow freely to
the cylinders, and the braking valve restricts the flow
from the cylinders back to the reservoir.
Single Acting Valve
Valve allowing hydraulic fluid to pass freely one way
(into the cylinders) and blocks the fluid coming back
until the valve is energized.
Switching Valve
Valve directing the flow of hydraulic fluid inside the
logic block.
E2051 Connection Block
A schematic, simplified, view of the E2051 connection
block.
Lift Cylinder
Schematic view of a lift cylinder.
Switch Contact
Switched used to make a momentary electrical
connection.

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6.2 POWER DOWN SCHEMATICS
•This schematic shows a power down unit at rest:

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•This schematic shows a power down unit with the LIFT function activated:

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•This schematic shows a power down unit with the LOWER function activated:

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6.3 GRAVITY DOWN SCHEMATICS
•This schematic shows a gravity down unit at rest: