The forklift is an established and indispensible workhorse of the industrial and warehousing world. It is a classic example of how modern machinery has allowed us to accomplish our work much more easily than a hundred plus years prior, so that with a forklift, one shift performed today by a forklift driver, or a robot forklift, in the early 1900’s would have been a day’s labor of back-breaking work for several men. This industrial vehicle is classified as a truck (i.e. “lift truck”), since its main function is to carry goods within a restricted work zone. They run on electric batteries or combustion engines that use various petroleum fuels (gasoline, diesel, LPG) and now there are some diesel -electric hybrid models also available. To be precise, a forklift is a truck with two power-mechanized forks (a.k.a. “blades”, “tines” or “prongs”) that are designed to lift heavy loads (with capacities from around 3K-30K lbs.) that are usually on top of a pallet, and to transport these loads to various locations within a work area, such as a production line, a storage area or a shipping bay.
The Industrial Truck Association (ITA), an influential trade association, representing most of the industrial lift truck manufacturers in North America, has categorized forklifts into eight different classes/types with lift code numbers, (see referenced websites), based on their power source and other design features. This classification is used as a government sanctioned reference system1:
Class 1: Electric engine, counterbalanced2, stand up or sit down, used primarily indoors, either of the two types of tires (cushion or pneumatic), and one of the four sub-types has three wheels instead of four.
Class 2: Electric engine, these forklifts are able to operate in a narrow aisle environment associated with inventory retrieval from shelves, used primarily indoors.
Class 3: Electric engine lifts, counterbalanced, used primarily indoors, that are a “walkies”, which means they are forklifts that are pushed around by a person on foot, not by a driver.
Class 4: Internal-combustion engine forklifts, counterbalanced, with cushion tires (a solid rubber tire, not relying on compressed air), mostly used outdoors
Class 5: Internal-combustion engine forklifts with pneumatic tires (a rubber tire filled with air), counterbalanced, mostly used outdoors
Class 6: both electric and internal-combustion engines for tow tractors lifts, sit down, with towing capacities from 2K -60K lbs, 3 types: caster steer, two wheel steer, four wheel steer
Class 7: Rough-terrain forklifts - the largest scale of the lifts, used outdoors for such industries as heavy construction, mining and agriculture.
Class 8: Personnel carriers and burden carriers (used for stationary loads on a small flat bed) are usually internal combustion vehicles.
One type of forklift not officially recognized by ITA or government regulators is the class of forked Automated Guided Vehicles (AGVs), which are software-driven forklift robots. These types of forklifts are typically priced a lot higher than a comparable mid-level human-driven forklift, but considering the labor cost savings, it can usually more than pay for itself in a few years.
When it comes to forklifts, safety is very important, and is even regulated by the governments and delegated organizations, due to the number of accidents and injuries that were occurring with these type of trucks. What’s the problem? The primary problem is because of tipovers caused by going too fast, and/or making sharp turns, and many times there are accidents because the lift falls forward due to the imbalance between the front load and rear counterbalance weight. There are also accidents related to the generally obstructed driver’s view because of the front load. Driver training is always required for certification and this can help with safety, but there is also a real need for the technology to improve, which is starting to happen. Some companies have begun to manufacture lifts equipped with a computer and sensors to monitor the center of gravity and the overall balance and stability, sometimes with the power to override the driver's control of the forklift if dangerous instability is detected.
Of course a prospective buyer of a forklift first considers the budget, whether or not they can afford a new or used lift; or one that is top quality or mid-level quality. Some other important considerations for a buyer would be how much lifting capacity will be needed and how much height is needed on the lifting mechanism to reach the shelves. Truck lifting capabilities typically range from around 3K to 35K lbs, and the upper height range for a standard pallet lift is around 40 feet.
1 Industrial Truck Association , https://www.indtrk.org/, and http://www.labour.gov.on.ca/english/hs/guidelines/lifttrucks/gl_lift_app..., http://www.wikimheda.com/wiki/index.php/Lift_truck_classification
2 “Counterbalanced” means that the forklift has an ultra-heavy metallic mass in the rear of the vehicle to counterbalance the heavy load-mass being lifted by the forks in the front. This is the primary measure taken to prevent forklifts from tipping over.