A forklift (also called a lift truck, a high/low, a stacker-truck, or a sideloader) is a powered industrial truck used to lift and transport materials. The modern forklift was developed in the 1920s by various companies including the transmission manufacturing company Clark and the hoist company Yale & Towne Manufacturing. The forklift has since become an indispensable piece of equipment in manufacturing and warehousing operations.
The middle 19th century through the early 20th century saw the developments that led to today's modern forklifts. The Pennsylvania Railroad
in 1906 introduced battery powered platform trucks for moving luggage at their Altoona, Pennsylvania train station. World War I
saw the development of different types of material handling equipment in the United Kingdom by Ransomes, Sims and Jeffries of Ipswich. This was in part due to the labor shortages caused by the war. In 1917 Clark
in the United States began developing and using powered tractor and powered lift tractors in their factories. In 1919 the Towmotor Company and Yale & Towne Manufacturing in 1920 entered the lift truck market in the United States.
Continuing development and expanded use of the forklift continued through the 1920s and 1930s. World War II, like World War I before, spurred the use of forklift trucks in the war effort. Following the war, more efficient methods for storing products in warehouses were being implemented. Warehouses needed more maneuverable forklift trucks that could reach greater heights. New forklift models were made that filled this need.
The following is a list of the more common lift truck types. It is arranged from the smallest type of lift to largest:
- Hand pallet truck
- Walkie low lift truck (powered pallet truck, usually electrically powered)
- Rider low lift truck
- Towing tractor
- Walkie stacker
- Rider stacker
- Reach truck (small forklift, designed for small aisles, usually electrically powered)
- Electric counterbalanced truck
- IC counterbalanced truck
- Telescopic handler
- Slip Sheet machine
- Walkie Order Picking truck
- Rider Order Picking truck (commonly called an "Order Picker"; like a small forklift, except the operator rides up to the load and transfers it article by article)
- Articulated Very Narrow Aisle Counterbalanced trucks (commonly called "Flexi Truck")
- Guided Very Narrow Aisle truck - 'Man Down' (a type of reach truck designed for aisles less than five feet wide) and 'Man Riser' Combination pickcle Picker/ Stacker truck
- Truck Mounted Forklift / Sod Loader
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 other 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.
- Guided Very Narrow Aisle Trucks
These are rail or wide guided and available with lift heights up to 40' non top-tied and 98' 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.
- U.S. Military 10K-AT "Adverse Terrain"
Counterbalanced forklift components
A typical counterbalanced forklift contains the following components:
- The 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.
- The Counterweight - is a heavy cast iron 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.
- The Cab - is the area that contains a seat for the operator along with the control pedals, steering wheel, levers, switches and 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.
- The 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 part of the frame assembly
- The Power Source - may consist of an internal combustion engine that can be powered by LP gas, CNG gas, gasoline or diesel fuel. Electric forklifts are powered by either a battery or fuel cells that provide power to electric motors. The motors 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 to assist in engaging a load.
- The 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 either hydraulically operated by one or more hydraulic cylinders or it may be chain operated with a hydraulic motor providing motive power. It may be mounted to the front axle or the frame of the forklift.
- The 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.
- The 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 consist of forks or tines that are the L-shaped members that engage the load. A variety of other types of material handling attachments are available. These include sideshifters, slipsheet attachments, carton clamps, multipurpose clamps, rotators, fork positioners, carpet poles, pole handlers, container handlers, roll clamps and many others.
Below is a list of common forklift attachments:
- Sideshifter - is a hydraulic attachment that allows the operator to move the tines (forks) and backrest laterally. This allows easier placement of a load without having to reposition the truck.
- Rotator - To aid the handling of skids that may have become excessively tilted and other specialty material handling needs some forklifts are fitted with an attachment that allows the tines to be rotated. This type of attachment may also be used for dumping containers for quick unloading.
- Fork Positioner - is a hydraulic attachment that moves the tines (forks) together or apart. This removes the need for the operator to get out of the cab to manually adjust the tines for different sized loads.
- Roll and Barrel Clamp Attachment - A mechanical or hydraulic attachment that is used for handling barrels, kegs, or paper rolls. This type of attachment also usually have a rotate function so that a vertically stored paper roll can be inserted into the horizontal intake of a printing press.
- Pole Attachments - In some locations, such as carpet warehouses, a long metal pole is used instead of forks to lift carpet rolls. Similar devices, though much larger, are used to pick up metal coils.
- Carton and Multipurpose Clamp Attachments - are hydraulic attachments that allow the operator to open and close around a load, squeezing it to pick it up. Products like cartons, boxes and bales can be moved with this type attachment. With these attachments in use, the forklift truck is sometimes referred to as a clamp truck.
- Slip Sheet Attachment (Push - Pull) - is a hydraulic attachment that reaches forward, clamps onto a slipsheet and draws the slipsheet onto wide and thin metal forks for transport. The attachment will push the slip sheet and load off the forks for placement.
- Drum Handler Attachment - is a mechanical attachment that slides onto the tines (forks). It usually has a spring loaded jaw that grips the top lip edge of a drum for transport. Another type grabs around the drum in a manner similar to the roll or barrel attachments.
- Man Basket - a lift platform that slides onto the tines (forks); meant for hoisting workers. The man basket has railings and brackets for attaching safety harnesses.
- Telescopic Forks - are hydraulic attachments that allow the operator to operate in warehouse design for "double-deep stacking", which means that two pallet shelves are placed behind each other without any aisle between them.
Forklift control and capabilities
Forklift trucks are available in many variations and load capacities. In a typical warehouse setting most forklifts used have load capacities between one to five tons. Larger machines, up to 50 tons lift capacity are used for lifting heavier loads, including loaded shipping containers
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
Forklifts are rated for loads at a specified maximum weight and a specified forward centre of gravity. This information is located on a nameplate provided by the manufacturer, and loads must not exceed these specifications(In Canada it is 24" Load Center). In many jurisdictions it is illegal to remove or tamper with the nameplate without the permission of the forklift manufacturer.
An important aspect of forklift operation is that many have rear-wheel steering. While this increases maneuverability in tight cornering situations, it differs from a driver’s traditional experience with other wheeled vehicles. While steering, as there is no caster action, it is unnecessary to apply steering force to maintain a constant rate of turn.
Another critical characteristic of the forklift is its instability. The forklift and load must be considered a unit with a continually varying centre of gravity with every movement of the load. A forklift must never negotiate a turn at speed with a raised load, where centrifugal and gravitational forces may combine to cause a disastrous tip-over accident. The forklift are designed with a load limit for the forks which is decreased with fork elevation and undercutting of the load (i.e. load does not butt against the fork "L"). A loading plate for loading reference is usually located on the forklift. A forklift should not be used as a personnel lift without the fitting of specific safety equipment, such as a "cherry picker" or "cage".
Lift truck associations and organizations
There are many national as well as continental associations related to the industrial truck industry. Some of the major organizations are listed as:
- Industrial Truck Association (ITA) (North America)
- Fédération Européenne de la Manutention - European Federation of Materials Handling (FEM)
- British Industrial Truck Association (BITA)
- Japan Industrial Vehicles Association (JIVA)
- Korean Construction Equipment Manufacturers Association (KOCEMA)
There are many significant contacts among these organizations and they have established joint statistical and engineering programs. One program is the World Industrial Trucks Statistics (WITS) which is published every month to the association memberships. The statistics are separated by area (continent), country and class of machine. While the statistics are generic, and do not count production from most of the smaller manufacturers, the information is significant for its depth. These contacts have brought to a common definition of a Class System which all the major manufacturers adhere to.
Forklift safety organizations
Forklift safety is subject to a variety of standards world wide. The most important standard is the ANSI B56—of which stewardship has now been passed from the American National Standards Institute
(ANSI) to the Industrial Truck Standards Development Foundation after multi-year negotiations. ITSDF is a non-profit organization whose only purpose is the promulgation and modernization of the B56 standard.
Other standards have been implemented in the United States by the Occupational Safety and Health Administration (OSHA) and in the United Kingdom by the Health and Safety Executive. In many countries forklift truck operators must be trained and certified to operate forklift trucks. Certification may be required for each individual class of lift that an operator would use.
Forklift Training in the United Kingdom
In the UK, Forklift Training
is monitored by a number of different organisations, which all Forklift Instructors must be registered with at least one of them. Although R.T.I.T.B. insist on 2 yearly refresher training, the amount of time determined between refresher courses is subject to H&S Executives, Insurance companies or company policies. H&S Executives do recommend re-training every 2 years.
United Kingdom Forklift Instructors must be registered to one of the following;
Road Transport Industry Training Board LTD (RTITB)
Independent Training Standards Scheme and Register (ITSSAR)
National Plant Operators Registration Scheme (NPORS)
Association of Industrial Truck Trainers (AITT)
There are various different training companies across the UK that can provide training on-site at your business premises, these can be independent instructors or part of a training company. There are also various training centre's across the United Kingdom that can provide individuals not already trained to use a Forklift Truck to help gain a licence.
In the United Kingdom training falls into four different categories;
REFRESHER - People who have gained a Forklift Training Certificate and need to be brought up to date with new laws and/or regulations.
CONVERSION - People who have been trained on a type of truck recently, and need to start using a different type.
SEMI-EXPERIENCED - People who are competent on a Forklift Truck, but have never been certificated.
NOVICE - Never been on a Forklift Truck before and never been certificated.
The courses can last for 1 day for a Refresher or a Conversion course, to 5 days for a Novice course. United Kingdom Forklift Instructors are allowed to train a maximum of Three People per day, this does not include classroom work.
Manufacturer's worldwide ranking
Below are the top ten maufacturers of the Powered Industrial Trucks market in terms of worldwide sales for 2006 - 2007.
- Toyota Industries (Japan) - BT, Cesab and Raymond Brands
- KION Group (Germany) - Linde and Still brands
- NACCO Industries, Inc. (USA) - Yale and Hyster brands
- Jungheinrich AG (Germany)
- Mitsubishi Caterpillar Forklifts, Inc. (Japan) - Mitsubishi Forklift Trucks and Cat Lift Trucks brands
- Crown Equipment Corporation (USA)
- Cargotec (Finland) - Kalmar brand
- Manitou (France)
- Komatsu Limited (Japan)
- Nissan Motor Company (Japan)
Forklift truck history
United Kingdom - Forklift Training Organisations