|
|||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||
"Pallet truck" redirects here. For the smaller pallet-moving tool sometimes called a pallet truck, see pallet jack.
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.1 The forklift has since become an indispensable piece of equipment in manufacturing and warehousing operations.
HistoryThe 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.2 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.3 Design typesThe following is a list of the more common lift truck types. It is arranged from the smallest type of lift to largest:
Specialty trucksAt the other end of the spectrum from the counterbalanced forklift trucks are more 'high end' specialty 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.
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.
Counterbalanced forklift componentsA typical counterbalanced forklift contains the following components:4
AttachmentsBelow is a list of common forklift attachments:5
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. 7 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. General operations
A forklift transporting a pallet of potted plants in Durham, North Carolina.
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 organizationsThere are many national as well as continental associations related to the industrial truck industry. Some of the major organizations are listed as:
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 organizationsStandardsForklift 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.14 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.15 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 KingdomIn the UK, Forklift Training is carried out 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 the H&S Executive, Insurance companies or company policies. The H&S Executive does recommend re-training/testing every 3 years. United Kingdom Forklift Instructors must be registered to one of the following; There are various different training companies across the UK that can provide training on-site and off-site, 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 certificate of competance. In the United Kingdom training falls into four different categories; Manufacturer's worldwide rankingBelow are the top ten maufacturers of the Powered Industrial Trucks market in terms of worldwide sales for 2006 - 2007.16
References
See alsoExternal linksWikimedia Commons has media related to:
Safety Information
Forklift truck history
[1] Contributor/Historian United Kingdom - Forklift Training Organisations
|
| All Right Reserved © 2007, Designed by Stylish Blog. |