Forklift Information
A fork lift or lift truck is an industrial
vehicle used to lift and transport materials, often by means of steel
forks mounted on the front. Forklifts are commonly used to move
loads on pallets by inserting the forks underneath. A fork lift can also
be know as a pallet truck, skid steer, hazwoper, or material handling
equipment. The forklift
originated in the 1920s by
various companies including Clark
and
Yale & Towne Manufacturing (Today known as Yale Materials Handling
Corporation). It has since become one of the most popular pieces of equipment
in warehousing and manufacturing operations.
Design Types
There are many different types of
industrial lift trucks in production today. The major ones are the
Hyster, Yale, Toshiba, Mitsubishi, CAT, and Clarke. There
are many significant differences between the manufactures but the basic
concept for a lift truck is generally constant a short bodied
maneuverable vehicle with a powerful engine and lifting forks mounted on
the front. The major types of forklifts are categorized with a common
definition of the Class System, which all the major manufacturers adhere
to. Following is the list of the more common truck types, from the
smallest to the biggest:
* Hand pallet truck
* Walkie low lift truck
* Rider low lift truck
* Towing tractor
* Walkie stacker
* Rider stacker
* Reach truck
* Electric counterbalanced truck
* IC counterbalanced truck
* Telescopic handler
* Slip Sheet machine
* Walkie Order Picking truck
* Rider Order Picking truck
* Very narrow aisle truck
Forklift Characteristics
A typical forklift may be generally described as follows:
* The truck proper, which is a motive machine with wheels and/or tracks powered through a drive train
* An LPG, gasoline or diesel fueled internal combustion engine, or an electric motor(s) either Direct Current or Alternating Current powered by either a battery or fuel cells.
* The mast, which is the vertical assembly that does the work of raising, lowering, and tilting the load; the mast is either hydraulically operated consisting of one or cylinder(s) and interlocking rails for lifting and lowering operations and for lateral stability, or it may be chain operated with a hydraulic motor providing motive power.
* The carriage, which comprises flat metal plate(s) and is moved along the mast either by means of chains, or by being directly attached to the hydraulic cylinder.
* One or more Forks, which are the L-shaped members that engage the load. The back vertical portion of the fork attaches to the carriage most often by means of a hook or latch (Class I to IV forks), some forks use a shaft mount. The front horizontal portion (which is usually tapered for ease of insertion) is inserted into or under the load, usually on a pallet or skid. Alternatively, a variety of other equipment is available, including slipsheet clamps, carton clamps, carpet rams, pole handlers, container handlers, roll clamps and others.
* A load back rest is fitted when the load is higher than the top of the carriage, and is a rack-like extension either bolted or welded to the carriage to prevent the load from shifting backward
* Rider operated machines have a driver's overhead guard, which is a metal roof, supported by posts, that helps protect the operator from any falling objects.
* The cab, which may contain a seat for the operator, along with the control pedals, steering wheel, levers, and switches and steering wheel for controlling the machine and a dashboard containing operator readouts. The cab may be open, or closed, but is bounded by the cage-like overhead guard assembly.
* Counterbalance machines have a counterweight, which is a heavy iron mass attached to the rear of the machine, necessary to compensate for the load. In an electric forklift, the large lead-acid battery itself may serve as part of the counterweight.
Control and Capability
Lift trucks are available in many variations with differing load capacities. A typical warehouse setting has forklifts using a load capacity of between one and five tons. The largest industrial forklifts today operate in the over 50 tons capacity.
The basic controls for a forklift include a lever to raise and lower the forks (also called tines or blades), a lever to tilt the forks (which aids in balancing loads) and a side-shift feature where the operator can shift a load horizontally by moving the forks left or right. Other features found on some lift trucks include the ability to rotate the forks, often used for dumping loads of liquid into another container. Many modern forklifts allow the operator to control the fork together or separately using hydraulics, giving more control on unbalanced loads.
Barrel or
Roll Clamp attachments are available to handle barrels, kegs, or paper rolls.
These give the lift truck operator the ability to Clamp pads that grab the load.
These
attachments also have a rotate function that makes it possible for vertically stored
paper rolls can be inserted into a horizontal intake printing press.
In carpet warehouses a long metal pole is often used on the front of a lift
truck to lift large carpet rolls. Similar poles are also used to
pick up metal rolls weighing up to 40 tons.
Forklift Safety
Forklift safety is subject to differing standards around the world. The most
common and universal standard is the ANSI B56 – which is currently
controlled by the Industrial Truck Standards Development Foundation. ITSDF is a non-profit organization whose purpose is the
promulgation and modernization of the B56 standard. The B56 standard is online
at the ITSDF website.
General
Forklifts are rated by load volume set at a specified maximum weight and a forward center of gravity. This information can be found on a nameplate attached by the manufacturer, and loads should not exceed these specification restrictions. In many states it is illegal to remove the nameplate without the manufacturer's permission.
Most forklifts have rear-wheel steering. While this increases tight cornering ability, it differs from the high speed responsiveness that most drivers are used to. The main difference is that maintaining the vehicle's course at speed requires control and skill by the operator. To replicate this effect imagine driving your car in reverse.
Another characteristic of the forklift is its balance; the forklift and load are considered a unit, with a varying center of gravity that changes with every movement and differing sized load. A forklift negotiates a turn at speed with a raised load will, in most cases, tip over causing an accident. The forks are designed with a load limit, which is decreased with elevation and distance of the load from the body of the truck (know as 'undercutting').
Today's Market
Six companies now dominate the forklift market in terms of worldwide sales. They are:
1. Toyota Industries Corporation
2. Linde Group
3. Jungheinrich
4. NACCO Industries
5. Mitsubishi Heavy Industries
6. Komatsu
Manufacturers
Over the course of history over 300 brands of forklift have been constructed. The Industrial Truck Association will be shortly publishing a private collection of forklift information that was gathered over the period of 30 years by the employee of a member company, which includes the names of these manufacturers, with some historical information. The database lists County of origin, known plants/sales offices, and types of machine manufactured. The terms of the donation were that the information be freely available through the ITA website.
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