In
addition to a control to raise and lower the forks (also known as
blades or tines), the operator can tilt the mast to compensate for a
load's tendency to angle the blades toward the ground and risk slipping
off the forks. Tilt also provides a limited ability to operate on
non-level ground. Skilled forklift operators annually compete in
obstacle and timed challenges at regional forklift rodeos.
Forklift Design Type
The following is a list, in no particular order, of the more common lift truck types:
Hand pallet truck - no on-board power system of any kind; the operator's muscle power is used to jack-up and move loads.
Walkie low lift truck - powered pallet truck, usually electrically powered
Rider low lift truck - usually electrically powered
Towing tractor
may be internal combustion engine or electrically powered
Walkie stacker - usually electrically powered
Rider stacker - usually electrically powered
Reach truck - variant
on a Rider Stacker forklift, designed for small aisles, usually
Electrically Powered, named because the forks can extend to reach the
load. There are two variants, moving carriage, which are common in North
America, and moving mast which are common in the rest of the world, and
generally regarded as safer
Electric counterbalanced truck - comes in Stand on End Control, Stand on Center Control, and Sit Down Center Control, which is the most numerous
Internal Combustion Engine Powered Counterbalanced Forklift - comes
in Stand on End Control, Stand on Center Control, and Sit Down Center
Control, which is the most numerous. Engines may be diesel, kerosene,
gasoline, natural gas, butane, or propane fueled, and may be either two
stroke spark ignition, four stroke spark ignition (common), two stroke
compression ignition, and four stroke compression ignition (common).
North American Engines come with advanced emission control systems.
Forklifts built in countries such as Iran or Russia will typically have
no emission control systems.
Electric forklifts - powered by lead-acid batteries or sometimes lithium-ion batteries,
several types of forklifts are electric: cushion tire forklifts,
scissor lifts, order pickers, stackers, reach trucks and pallet jacks.
Electric forklifts are primarily used indoors on flat, even surfaces.
Electric forklift batteries last 6 consecutive hours or throughout an
8-hour shift with 2-3 breaks. Batteries prevent the emission of harmful
fumes and are recommended for facilities in food-processing and
healthcare sectors.
Fuel cell forklifts - produce
no local emissions, can work for a full 8-hour shift on a single tank
of hydrogen, can be refueled in 3 minutes and have a lifetime of 8–10
years. Fuel-cell-powered forklifts are often used in refrigerated
warehouses as their performance is not degraded by lower temperatures.
Sideloader - comes
in Stand on End Control, and Sit Down End Control, which is the most
numerous. It may be electrically powered, or have an internal combustion
engine. Engines may be diesel, kerosene, gasoline, natural gas, butane,
or propane fueled, and may be either two stroke spark ignition, four
stroke spark ignition (common), two stroke compression ignition, and
four stroke compression ignition (common). North American Engines come
with advanced emission control systems. Forklifts built in countries
such as Iran or Russia will typically have no emission control systems.
Some sideloaders have hybrid drivetrains.
Telescopic handler - comes
in Stand on Center Control, and Sit Down Center Control, which is the
most numerous. Usually has an Internal Combustion Engine. Engines are
almost always diesel, but sometimes operate on kerosene, and sometimes
use propane injection as a power boost. Some old units are two stroke
compression ignition, most are four stroke compression ignition
(common). North American Engines come with advanced emission control
systems. Forklifts built in countries like Iran or Russia will typically
have no emission control systems. Some Telescopic handlers have Hybrid
drivetrains.
Walkie order picking truck - usually Electrically Powered
Rider order picking truck - commonly
called an "Order Picker"; like a small Reach Truck, except the operator
rides in a cage welded to the fork carriage, while wearing a specially
designed safety harness to prevent falls. A special toothed grab holds
the pallet to the forks. The operator hand transfers the load onto the
pallet one article at a time. This is an efficient way of picking less
than pallet load shipments, and is popular for use in large distribution
centers.
Articulated very narrow aisle counterbalanced trucks - sometimes
called "Flexi or Bendi Trucks" after two of the largest manufacturers.
Comes in stand on center control, and sit down center control, which is
the most numerous. May have an internal combustion engine or an electric
motor. Electric motors are most common. Engines may be diesel,
kerosene, gasoline, natural gas, butane, or propane fueled, and may be
either two stroke spark ignition, four stroke spark ignition (common),
two stroke compression ignition, and four stroke compression ignition
(common). North American Engines come with advanced emission control
systems. Forklifts built in countries such as Iran or Russia will
typically have no emission control systems. Some units have hybrid
drivetrains. Unlike
Standard Counterbalance and Reach Forklifts, These forklifts are
steered via the front swivel articulation of the forklift and are
therefore much different to manoeuvre than regular forklifts and
additionally have no pantograph feature for retrieving stock in narrow
aisles.
Guided very narrow aisle truck - A
counterbalance type Sit Down Rider Electric Forklift fitted with a
specialized mast assembly. The mast is capable of rotating 90 degrees,
and the forks can then advance like on a reach mechanism, to pick full
pallets. Because the forklift does not have to turn, the aisles can be
exceptionally narrow, and if wire guidance is
fitted in the floor of the building the machine can almost work on its
own. Masts on this type of machine tend to be very high. The higher the
racking that can be installed, the higher the density the storage can
reach. This sort of storage system is popular in cities where land
prices are really high, as by building the racking up to three times
higher than normal and using these machines, it is possible to stock an
incredible amount of material in what appears to be a small space.
Guided very narrow aisle order picking truck - counterbalance
type Order Picking Truck similar to the guided very narrow aisle truck,
except that the operator and the controls which operate the machine are
in a cage welded to the mast. The operator wears a restraint system to
protect him against falls. Otherwise the description is the same as
guided very narrow aisle truck.
Truck-mounted forklift / sod loader - comes
in sit down center control. Usually has an internal combustion engine.
Engines are almost always diesel, but sometimes operate on kerosene, and
sometimes use propane injection as a power boost. Some old units are
two-stroke compression ignition, most are four-stroke compression
ignition (common). North American engines come with advanced emission
control systems. Forklifts built in countries such as Iran or Russia
will typically have no emission control systems.
Forklift Cost
The
cost of a new forklift can vary between $15,000 to in excess of
$150,000, depending on the model and, in particular, the capacity of the
forklift. The most common forklifts are typically gas powered and have a
capacity of between 2 and 2.5 tonnes. The cost of these varies from
around $18,500 for some of the lesser well known Chinese-manufactured
forklifts to around $20,000 for the German forklifts from
well-established manufacturers. It is important to take fuel and
maintenance costs into account when calculating the total cost of
ownership
Specialty trucks
At the other end of the spectrum from the counterbalanced forklift trucks are more 'high end' specialty trucks:
Articulated counterbalance trucks - These
are, unlike most lift trucks, front wheel steer, and are a hybrid VNA
(very narrow aisle) truck designed to be both able to offload trailers
and place the load in narrow aisle racking. Increasingly these trucks
are able to compete in terms of pallet storage density, lift heights and
pallet throughput with guided very narrow aisle trucks, while also
being capable of loading trucks, which VNA units are incapable of doing.
Guided very narrow aisle trucks - These
are rail- or wire-guided and available with lift heights up to 40 feet
non-top-tied and 98 feet top-tied. Two forms are available: 'man-down'
and 'man-riser', where the operator elevates with the load for increased
visibility or for multilevel 'break bulk' order picking. This type of
truck, unlike articulated narrow aisle trucks, requires a high standard
of floor flatness.
Omnidirectional trucks - Omnidirectional technology (such as Mecanum wheels)
can allow a forklift truck to move forward, diagonally and laterally,
or in any direction on a surface. Omnidirectional wheel system is able
to rotate the truck 360 degrees in its own footprint or strafe sideways
without turning the truck cabin. One example is the Airtrax Sidewinder.
This forklift truck has also made an appearance in the TV series called
'Mythbusters'.
UL 558 safety rated trucks - In North America, some internal combustion powered industrial vehicles carry Underwriters Laboratories ratings
that are part of UL 558. Industrial trucks that are considered "safety"
carry the designations GS (Gasoline Safety) for gasoline powered, DS
(Diesel Safety) for diesel powered, LPS (Liquid Propane Safety) for
liquified propane or GS/LPS for a dual fuel gasoline/liquified propane
powered truck.[18]
UL 558 is
a two-stage Safety Standard. The basic standard, which is G, D, LP, and
G/LP is what Underwriter's Laboratories considers the bare minimum
required for a lift truck. This is a voluntary standard, and there is no
requirement in North America at least by any Government Agency for
manufacturers to meet this standard.
The
slightly more stringent GS, DS, LPS, and GP/LPS, or Safety standard
does provide some minimal protection, however it is extremely minimal.
In the past Underwriter's Laboratory offered specialty EX and DX safety
certifications. If you require higher levels of protection
you must contact your local Underwriter's Laboratory Office and check
ask them what the correct safety standard is for your workplace.
UL 583 safety rated trucks - UL 583 is the Electric equivalent of UL 558. As with UL 558 it is a two-stage standard.
Explosion proof trucks "EX RATED" - These
are for operation in potentially explosive atmospheres found in
chemical, petrochemical, pharmaceutical, food and drink, logistics or
other industries handling flammable material. Commonly referred to as Pyroban trucks
in Europe, they must meet the requirements of the ATEX 94/9/EC
Directive if used in Zone 1, 2, 21 or 22 areas and be maintained
accordingly.
U.S. Military 10K-AT "Adverse Terrain"
Automated forklift trucks - In order to decrease work wages, reduce operational cost and improve productivity, automated forklifts have also been developed.
Automated
forklifts are also called forked automated guided vehicles and are
already available from a growing number of suppliers.
Counterbalanced forklift components
Truck frame -
is the base of the machine to which the mast, axles, wheels,
counterweight, overhead guard and power source are attached. The frame
may have fuel and hydraulic fluid tanks constructed as part of the frame assembly.
Counterweight -
is a mass attached to the rear of the forklift truck frame. The purpose
of the counterweight is to counterbalance the load being lifted. In an
electric forklift the large lead-acid battery itself may serve as part
of the counterweight.
Cab/Operating Seat - is the area that contains a seat for the operator along with the control pedals, steering wheel, levers, switchesand
a dashboard containing operator readouts. The cab area may be open air
or enclosed but it is covered by the cage-like overhead guard assembly.
When enclosed, the cab may also be equipped with a cab heater for cold
climate countries along with a fan or air conditioning for hot weather.
Overhead guard - is a metal roof supported
by posts at each corner of the cab that helps protect the operator from
any falling objects. On some forklifts, the overhead guard is an
integrated part of the frame assembly.
Power source - may consist of an internal combustion engine that can be powered by LP gas, CNG, gasoline or diesel fuel. Electric forklifts are powered by either a battery or fuel cells that provides power to the electric motors. The electric motors used on a forklift may be either DC or AC types.
Tilt cylinders -
are hydraulic cylinders that are mounted to the truck frame and the
mast. The tilt cylinders pivot the mast backward or forward to assist in
engaging a load.
Mast -
is the vertical assembly that does the work of raising and lowering the
load. It is made up of interlocking rails that also provide lateral
stability. The interlocking rails may either have rollers or bushings as
guides. The mast is driven hydraulically,
and operated by one or more hydraulic cylinders directly or using
chains from the cylinder/s. It may be mounted to the front axle or the
frame of the forklift. A 'container mast' variation allows the forks to
raise a few meters without increasing the total height of the forklift.
This is useful when double-loading pallets into a container or under a
mezzanine floor.
Carriage -
is the component to which the forks or other attachments mount. It is
mounted into and moves up and down the mast rails by means of chains or
by being directly attached to the hydraulic cylinder. Like the mast, the
carriage may have either rollers or bushings to guide it in the
interlocking mast rails.
Load back rest -
is a rack-like extension that is either bolted or welded to the
carriage in order to prevent the load from shifting backward when the
carriage is lifted to full height.
Attachments -
may consists of a mechanism which is attached to the carriage, either
permanently or temporarily, to help in proper engagement of the load. A
variety of material handling attachments are available. Some attachments
include sideshifters, slipsheet attachments, carton clamps,
multipurpose clamps, rotators, fork positioners, carpet poles, pole
handlers, container handlers and roll clamps.
Tires - either solid for indoor use, or pneumatic for outside use.