WALKIE LIFT TRUCKS
Key concepts
o
Class 3 walkie trucks
perform loading, unloading, order picking, stacking, staging, and internal
transportation duties.
Walkie equipment
is divided into low-lift and high-lift stacker versions.
Ergonomic and safety features are key ingredients in
every vehicle.
o
Class 3 walkies are
battery-powered alternatives to hand trucks and manual pallet jacks. These
motorized hand trucks are found in virtually every manufacturing and
distribution operation performing loading, unloading, order picking, stacking,
staging, and internal transportation duties. They account for 24% of all
industrial vehicles sold.
The motorized vehicles allow the operator to deliver
or store the load much faster than using manual equipment. At the same time,
operator fatigue is reduced and the possibility of injury associated with
manually moving heavy materials is virtually eliminated.
On the down side, the vehicles typically have lower
travel and lift speeds, which may limit their productivity in demanding
operations or those covering greater distances. Capacity is limited to about
8000 lb (4000 lb for higher lifts); however, specially designed and constructed
versions can go much higher. Gradeability is also a
concern for some equipment.
There are a wide range of designs and functions
available. Most types are low lift, but equipment reaching 16 ft or so are
available. Most vehicles are walkies, but numerous
rider versions are on the market.
General features
Motorized hand trucks are operated by an end control
handle mounted at the end of a tiller steer arm. The steer handle (or head)
regulates lift and lower functions, speed, direction, steering, braking, and
several safety features. Some rider versions have a center control handle
located on the riding platform between the battery and forks.
Nearly all Class 3 vehicles use transistor-type
controls. These devices provide smooth acceleration, infinite travel speeds,
easy maneuverability, and high energy efficiency.
Drive tires are constructed from polyurethane or
rubber, with the latter offering better traction.
Load wheels under the forks (and load) are small
diameter and usually made from hard polyurethane, which provides better wear
than rubber.
Walkies operate
with 12 or 24-V batteries, with the latter used on riders and more demanding
applications. The advent of the maintenance-free or sealed-cell battery has
been a major boost to truck performance. The batteries easily serve an 8-hr
shift.
Matching the technology of the vehicle with operator
capabilities and needs maximizes safety and performance. Consequently,
ergonomic and safety features are an important part of every vehicle.
The trucks include contoured handles that make it
easier for the operator to steer and control the trucks over longer periods of
time. The control handle is designed for minimal wrist exertion. Riders have
safety bars and padding. The vehicles have a low profile to improve visibility,
and shorter head length to increase maneuverability. Improved braking systems
and autoreverse features protect the operator.
Ultimately, however, an educated, attentive, and
conscientious operator is the best safety feature the vehicle can have.
A variety of options can be added to the basic truck
package. Possibilities include battery discharge indicators, built-in battery
chargers, battery roller conveyors, side shifters, cold storage or corrosion
protection, hour meters, audible alarms, lift interrupts, and stability
casters. Various fork widths and lengths are available. Stacker trucks can
employ a variety of handling attachments.
Types
Generally speaking, Class 3 equipment is divided into
low-lift and high-lift stacker versions. Low-lift models handle floor level
pallets or skids. High-lift equipment has stacking capability and is offered in
straddle, reach, and counterbalanced versions.
Low lift
Low-lift walkies often
called pallet trucks, are the dominant player in the
Class 3 category with nearly half of the unit sales. Forks are inserted between
the top and bottom boards of pallets to raise the load a few inches off the
ground for transport. These products are not used for stacking.
Walkie trucks
lift the pallet 6 in. off the floor to allow free travel over dock boards,
ramps, and obstacles. Transistorized controller allows infinitely variable drive
speeds.
The truck features a speed control device (thumb or
twist handle) to match the pace of a walking worker. They are capable of moving
about 4 mph when empty, and about half that loaded. Maximum capacity is 8000
lb.
Low-lift riders generate about 30% of the market and
use the same lifting mechanism and perform the same handling tasks as the walkie. Obviously, this type is used when longer travel
distances or quicker handling is required.
Walkie/rider
pallet trucks travel about 8 mph when empty, which is two or three times faster
than walking but slower than a traditional lift truck.
The operator stands on a rear platform, or in a
compartment between the batteries and forks. Most riders can also be operated
in a walkie mode.
Tow tractors
(tuggers)
are available in walkie or rider versions and pull up
to three carts of picked material in train fashion. A coupler engages the
towing arm of the cart to move the train.
Tuggers are an
effective approach for moving high volumes of material along varied paths in
the plant. They are capable of moving a 12,000-lb rolling load about 5 mph.
High lift
High-lift walkies take
2000­4000 lb up to about 16 ft using a
multistage mast. This walkie is the best choice when
the frequency of use does not justify the higher expense associated with a
Class 1 electric rider lift truck or Class 2 narrow aisle vehicle.
Straddle stackers are used in narrow aisle
applications. Outriggers straddle the load, which reduces the length of the
truck and eliminates the need to counterbalance the load weight. Some stackers
do not have outriggers.
Reach trucks require a slightly larger aisle than
straddle types, but offer greater flexibility in load sizes handled. A scissor
mechanism (pantograph) extends the forks beyond the outriggers to access and
load, eliminate the straddles, and place material one pallet deep.
Straddle stackers are typically used in narrow-aisle
storeroom and warehouse areas to handle uniform load sizes up to 4000 lb.
Reach trucks offer the maneuverability and
economy of a walkie with the stacking capability of a
counterbalance rider or narrow aisle vehicle.
Counterbalanced trucks are similar to Class 1 riders
in that they use the frame design and counterweighting
to offset the force of the load held in front of the mast. These vehicles stack
two high, and service all types of storage racks except double deep, which
require a double-deep reach truck.
Counterbalanced walkie
stackers are available in 12 and 24-V versions, lift at 30 fpm, and lower at 49
fpm with a 4000-lb load.
Selection considerations
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Application (light, medium, or heavy duty)
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Operation (continuous or intermittent)
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Purchase price
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Operating costs
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Maintenance and repair
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Aisle characteristics
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Travel distances
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Load size
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Product mix
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Product configuration
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Storage or stacking requirements