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COMPONENTS
A lot of aerial lifts are powered up and go down by gravity, with
APPLICATION the user having control over both directions for their personal
safety. The hydraulic valves used include electro-hydraulic
proportional directional flow controls, check and relief val-
STRADDLE ves, as well as selector valves, providing precision control to
ensure stable and efficient operation involving vertical and
rotational movements. Wandfluh cartridge valves and stan-
CARRIER dard flange mount directional valves offer flexible, reliable and
safe multifunction control of the hydraulics across small and
large aerial work platforms, scissor lifts, and self-propelled
boom lifts.
In a globalized world in which container ships with SPECIALTIES
several thousand containers call at the world's lar- • Special Lift & Lower all-in-one valves to reduce cavity
gest ports, the loading and unloading of ships is count and leak paths FUNCTION
supported by fully automated systems. The cont- • Zero leak poppet technology for ‘lock-in-place’ and fluid Generally used for temporary, flexible access purposes such
ainers are stacked by self-propelled lifting cranes, direction functions as maintenance and construction work or by firefighters for
emergency access, which differentiates them from perma-
known as straddle carriers, in a temporary storage • High repeatability flow control valves for smooth speed nent access equipment such as elevators. They are designed
facility in the port area. The hydraulics and elec- control of functions over entire range to lift limited weights separating them from most types of
tronics installed in the straddle carrier are often cranes. They are usually capable of being set up and opera-
ted by a single person.
in operation 24 hours a day, and a system failure The hydraulic systems are typically very compact, mounted in
would result in very high costs. the unit base and control the extension and retraction of the
lift cylinders in the bucket by the operator. Several functions
may be controlled such as steering left/right, propel forward
and reverse and bucket lift and lower as well as bucket tilt
and levelling.

CAN 3
power supply 24VDC
CAN 4
CAN 1
steering unit
8 x valves
A B
a b
P T solenoid outputs steering
controller digital vehicle APPLICATION
computer
8 x pressure p analog inputs in / outputs COMPONENTS
s
At the heart of the system is the SIL2-capable steering cont-
CAN 2
roller. The steering unit transmits the values to the controller AERIAL
via a redundant CANbus system, which compares and re-
RS232 gulates the positions using robust angle sensors. The pro-
8 x rotary encoder wheel angle
PASO portional amplifier electronics are then used to control the PLATFORM
proportional spool valves and regulate the steering angle of
the axle. All components are matched to each other, which
FUNCTION allows for simple commissioning and controlled operation. An aerial work platform (AWP), also known as an
Several straddle carriers are each controlled from a control
room. The dispatcher simply tells the vehicle the desired end SPECIALTIES aerial device, elevating work platform (EWP), aerial
position, everything else is managed independently by the ve- lift, cherry picker, bucket truck or mobile elevating
hicle. Due to its high payload, a straddle carrier has six to eight • Integrated manual vehicle steering and various driving work platform (MEWP) is a hydraulically powered
axles, which are individually hydraulically controlled, regulated modes
and monitored via proportional valves. For safety reasons, the • Various additional safety functions can be added mechanical device used to provide temporary ac-
entire hydraulic system, including the control electronics and cess for people or equipment to inaccessible areas,
axle control, is kept redundant, similar to aircraft construction. • Parameterization software for commissioning and usually at height. There are distinct types of me-
In addition to increased safety, this increases the availability maintenance
of the system. This virtually eliminates system failures and the chanized access platforms and the individual types
associated time delays in 24-hour port operations. • Completely balanced system. may also be known as a "cherry picker", "boom lift"
Hydraulics and electronics from a single source
or "scissor lift".

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