This article takes an in depth look at forklift trucks regarding their use and types.
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A forklift truck is an electrical or gas powered industrial piece of equipment with a metal fork platform attached to its front that can be used to lift heavy loads by inserting the fork platform under cargo, pallets, or machines for moving them or placing them in storage. The truck frame of a forklift truck forms the base for its lifting and includes wheels, counterweights, a carriage, and a mast.
The two types of engines for forklift trucks are electrical or gas with gas being Liquefied Petroleum Gas (LPG), compressed natural gas (CNG), diesel, or natural gas. Electric forklift trucks get their power from rechargeable lead acid batteries or fuel cells.
Forklift trucks are used in warehouses, manufacturing and industrial operations, shipping docks, and truck loading and unloading. Since they come in a wide variety of sizes and power sources, they are found at small businesses and large complex industrial manufacturing operations. Their applications and uses are endless.
Forklift trucks are designed to safely and efficiently lift heavy loads that are beyond human capabilities. They are an indispensable tool that helps to increase the productivity of a work site and process while keeping workers protected. The description of a forklift truck is based on its classification, which includes its workload, capacity, size, terrain, and any special features or capabilities it may have.
Heavy loads come in as many types as there are pieces of equipment to lift them. Forklift trucks used to make those lifts have to have the components necessary to easily and safely lift a heavy load as well as be able to place it. Each forklift truck is chosen to fit the needs of the industry it serves and meet the needs of that industry’s workload.
Articulated forklift trucks, also known as swing mast forklift trucks, are able to load and unload materials in narrow aisles. The fork platform of an articulating forklift truck can be turned right or left without having to move the truck. This allows the truck to face in a straight line as the forks are turned or twisted to access the load. They are ideal for small spaces, small trucks, and cold storage units.
Counterbalance forklifts are one of the most common forms of forklifts and come in three and four wheel models. The forks of a counterbalance forklift truck stick out from the front of the truck with legs or arms for stabilization. The name of a counterbalance forklift truck comes from the counterweight at the rear of the truck behind the motor. It is positioned such that it compensates for heavy loads.
The turning radius of a counterbalanced forklift truck is very wide, which limits its operational area. Their classification requires that they be operated on level ground. A unique feature of counterbalance forklifts is their ability to drive right up to a load instead of reaching for it. This ensures a safe lift and a tight connection between the load and the forklift.
Side loader forklift trucks lift loads from the side and are a narrow aisle form of forklift truck. While the truck for a side loader forklift truck runs in a straight line, its forks hang off to the side. This design makes them ideal for narrow aisles where other forklift trucks cannot maneuver. Side loader forklift truck forks are mounted perpendicular to the body and the direction of the truck’s movement and can rotate 90o with a load.
There are two possible operating positions for a side loader forklift truck, which are a man up or man down. In the man up model, the operator is close to the load. With the man down version, the operator manipulates the forklift truck while standing on the ground. This particular design is one of the many features of side load forklift trucks, which makes them a very flexible and adaptable piece of equipment.
Reach forklift trucks are a form of narrow aisle forklift used in warehouses and have two outer legs to distribute the load with a set of wheels in the back located below the operator. They have a long horizontal platform behind the mast that allows the forklift to pick up bulky and heavy items in high places.
The popularity of reach forklift trucks is due to their ability to provide portability and stability that larger and more powerful units cannot provide. They use their elevated platform to access tight spaces where there is limited headroom.
A turret truck forklift is a counterbalanced narrow aisle forklift and has an articulating base that rotates the forks 180o. They are ideal for order picking in high rack warehouses and have navigation systems that help them avoid obstacles. Turret trucks can fully rotate their forks while their truck remains immobile. The main mast and front mast of a turret truck forklift extends much higher than a typical forklift, while its steering and safety features are the same as a counterbalanced forklift truck.
A rough terrain forklift truck is designed to be driven over uneven, rocky, and pot hold surfaces while carrying heavy loads. They are large, heavy, and have tires designed to withstand the demands of a rough rugged surface. Three of the types of rough terrain forklift trucks are telehandler or telescopic, rotating telehandler, and straight mast.
Telehandler or Telescopic – A telehandler forklift truck has a telescoping boom that allows it to pick and place loads at various distances and heights. They are capable of lifting full loads from 18 feet up to over 50 feet with a load capacity of 5500 lbs. too close to 12,000 lbs. Telehandlers have all wheel steering to easily position a load close to the work site. The boom’s movements are controlled by a joystick for movement and placement of loads.
Rotating or Roto Telehandler – Rotating telehandlers are set on a base that allows them to rotate a full 360o, which means that the boom and operator rotate while the base remains immovable. As with the standard telehandler forklift truck, rotating telehandlers have a telescopic boom that is able to reach higher and move heavy loads. The motor and engine for a rotary telehandler are located in the lower section with the wheels and chassis.
Straight Mast – As with telehandler forklift trucks, straight mast forklifts are designed for loading and unloading of exceptionally heavy items. They are easily maneuverable and accessible due to their heavy duty pneumatic tires, which are larger than other rough terrain forklift trucks. Straight mast forklift trucks come in three and four wheel versions and are powered by propane or diesel fuel.
The traditional view of a forklift is a driver seated in a cab with a steering wheel and levers to manipulate the boom and forks. Although this is the common view, it does not apply to all forklift maneuvering methods. The type of forklift where the operator sits or stands in the forklift is referred to as a sit down forklift where the driver does not have to move to make a lift or place a load.
Another version of a forklift truck is referred to as a stand up forklift truck where the operator frequently leaves the truck to load and unload items, stack inventory, or scan barcodes. There is a wide assortment of stand up forklifts, which include order pickers, pallet jacks, stand up trucks, double deep trucks, saddled trucks, and walkie stackers.
Order picker trucks function like a forklift and are controlled from a carriage on the truck where the operator is able to maneuver and position it. They have fixed forks or a working platform that is used to load products during the picking process. The forks on an order picker truck are set in a fixed static position and raised and lower with the operator. They make it possible to carry a pallet for loading or picking up items. The platform can raise the operator to pick items from warehouse racks and can reach heights of near 40 feet or higher.
A stand up forklift truck makes it easy for the operator to hop on and off. They are a three wheel type of forklift that can turn easily in tight spaces. Stand up trucks have a counterbalance that is similar to a full sized counterbalanced forklift but in a smaller size. They are normally battery powered and operate very quietly. The design of stand up forklifts makes it possible for them to operate in close quarters and narrow aisles. Their movement is powered by a pedal on the floor for the operator platform while a handle controls the direction or steering.
Double deep forklift trucks are designed to work with double deep pallet racking. The forks on a double deep forklift truck can be extended to reach into double deep racking and have an outrigger to counterbalance the weight of loads. They can reach further and handle heavier loads than single reach forklifts.
A walkie forklift is a walk-behind forklift that has a mast for lifting pallets. It has a similar function as a counterbalanced forklift and operates well in narrow aisles and tight spaces. They are commonly used to move and position pallets much like a pallet jack and are a perfect alternative for larger forklifts and small warehouse operations.
Power for a walkie forklift can be manual or powered. For the manual version, the forklift has a peddle or handle that is pumped to raise the forklift’s forks. When the load needs to be lowered, a button is pushed to release the pressure. The powered version has buttons for raising and lowering the load as well as moving the forklift.
Forklift trucks are heavy duty industrial vehicles that are used for moving, positioning, loading, and unloading materials and products. They have distinctive components made of resilient and strong metals that are capable of withstanding stressful and demanding working conditions. Since their introduction in 1867, in the middle of the first industrial revolution, forklift trucks have become an essential safety device used for industrial and manufacturing operations.
Each of the elements of a forklift truck is carefully chosen to meet the standards of the Occupational Safety and Health Administration (OSHA), which has classifications and regulations regarding the weight capacity and performance of forklift trucks. Each part, from the motor to the lifting forks, is selected to fit specific working and lifting requirements.
The frame of a forklift truck forms the foundation upon which the elements of the forklift rests and is the basic part of all forklifts. The mast, wheels, and counterweight are attached to the frame as well as the engine, motor, and lifting components.
The counterweight is attached to the rear of the forklift and is designed to counterbalance the lifted load. In battery operated forklift trucks, the weight of the battery may be sufficient to serve as the counterweight. When a load is lifted, the load is kept as near as possible to the front wheels to keep the load centered. The counterweight keeps the forklift from tipping forward.
This particular aspect of forklift truck operations is for which OSHA has established classifications to protect workers and ensure forklifts are only lifting loads that meet their abilities.
The power source for forklifts can be electricity or gas with electric forklift trucks running on huge industrial size batteries and gas forklift trucks using internal combustion engines. The main types of gas fuels are diesel, liquid petroleum gas (LPG), compressed natural gas (CNG), and gasoline.
The electric motors for forklift trucks can be direct or alternating current powered by batteries or fuel cells. They need to be charged for eight hours to be able to operate at maximum efficiency. Although electric forklifts have an initial higher expense, they rarely need upkeep or maintenance and can run for over five years. They have superior maneuverability compared to gas operated forklifts and have a noiseless startup.
Gas powered forklift trucks are more widely used than electric forklift trucks. They are less expensive and have greater versatility. Their high speed acceleration and operation assists in warehouse efficiency and effectiveness. They do need regular maintenance and have to be checked several times a year for gas usage, oil, worn parts, and potential mechanical failures, which is unnecessary for electrical forklift trucks.
The carriage is the part of the forklift onto which the forks are mounted. It is connected to the mast such that it moves the forks up and down. The motion of the carriage is created by a chain drive or hydraulic cylinder with rollers or bushings to guide it. Carriages are classified by their lifting capacity and height, which is the distance between the top edge of the carriage and the lower edge of the fork bar. The five classifications for carriages are:
Class 1 – Carriage height of 13 inches with a lifting capacity of fewer than 1.1 tons.
Class 2 – Carriage height of 16 inches and lifting capacity between 1.1 and 2.75 tons.
Class 3 – Carriage height 20 inches and lifting Capacity: Between 2.75 and 5.5 tons
Class 4 – Carriage height of 25 inches and lifting capacity: between 5.5 and 8.8 tons
Class 5 – Carriage height of 28.7 inches and lifting capacity between 8.8 and 12 tons.
Carriage classifications are a shorthand way for determining the type of forklift truck for a job and provide a clear understanding of its forks and capabilities.
The mast of a forklift truck, also known as its upright, is the vertical assembly that raises and lowers loads. It includes interlocking rails that provide lateral stability with rollers or bushings as guides. The mast has an elevating mechanism that involves the use of a hydraulic cylinder and chain drives with multiple sections that work together to lift loads. There are four types of forklift masts that are categorized by their number of stages.
Included in the description of forklift truck masts is the term free lift, which refers to the height an operator can raise the forklift’s forks without having to change the mast height.
Single Stage: A single stage mast or simplex mast has one channel and has a limited lifting distance. They have a stationary outer rail and a sliding inner rail with a chain drive for lifting. Single stage forklift trucks do not have free lift.
Two Stage: A two stage mast or duplex mast has a hydraulic cylinder in the middle of the mast to push loads up, which allows loads to rise as the mast remains stationary. When the carriage reaches the top of the inner rails, the side rails complete the lifting of the load. The inner section raises the carriage and forks while the outer section remains motionless.
Three Stage: The three stage or triplex mast is the most common type of forklift truck mast. The mechanism has two sliding rails, a stationary rail, and a large hydraulic cylinder at the center of the mast that does most of the lifting. Secondary hydraulic cylinders lift the middle section and chain system, which pulls the inner section and carriage at full extension. Three stage masts provide for free lift.
Four Stage: Of the four types of masts, the four stage or quad mast has the highest reach. It has four sets of moving rails and chains with restricted visibility through the mast due to the complexity of the mechanism. The productivity of a four stage mast is dependent on powerful secondary hydraulic cylinders, rails, and chain drives, which give it free lift and the ability to reach the highest of the four mast types. The intricacy of the four stage mast requires special training and certifications to be able to operate it.
The selection of a forklift truck is contingent on the overhead clearance of the facility where it will be used since that is the physical restriction in regard to the type of mast a forklift will have. A forklift truck’s carriage and forks should be able to reach the highest shelves in a facility with a six inch gap. The height of the mast is determined by the distance from the floor of a facility to the top of the mast, which is referred to as its fully extended height. The lowered height is the distance from the floor to the top of the fully lowered mast.
The lift cylinder of a forklift truck provides the power for the vertical movement of the mast that raises and lowers the carriage and forks. Lift cylinders are hydraulically powered and push in one direction. A control valve directs hydraulic fluid flow to the cylinder when completing a lift.
When the control valve is moved to the lower position, the weight on the mast forces the fluid to flow back to the storage tank. The back flow is carefully regulated by the control valve to ensure a smooth and even lowering motion.
The tilt cylinder is a double acting cylinder that can push or pull a load. Most forklift trucks have two tilt cylinders connected to the stationary rails of the mast. The placement of the tilt cylinders provides for uniform movement control and prevents the mast from shifting from side to side.
The forks or tines make contact with the load and are attached to the carriage. They make the connection with the bottom of the load and come in varying shapes, lengths, and sizes. Forklift forks are long extensions, much like arms, capable of supporting the load. The types of forks for a forklift truck match carriage classifications for carriage height and capacity.
The dimensions and conditions of the forks guarantee the safe operation of a forklift and prevent possible damage. They need to be inspected regularly for cracks, straightness, and angle. Hooks should be checked for cracks, exterior damage, and wear.
There are a wide variety of forklift tires and tire layouts. Four wheel forklift trucks are capable of lifting huge loads and function successfully in many varied applications.
Three wheeled forklifts are ideal for narrow aisles and where space is limited. They turn efficiently and easily. The two common types of tires are:
Cushion Tires: Cushion tires are made of solid rubber and are less expensive to make and easy to maintain. They are designed for indoor forklift use on smooth even surfaces. Cushion tires are easier to maneuver in cramped small spaces due to their smaller turning radius and are capable of lifting up to 8 tons.
Pneumatic Tires: Pneumatic tires are like car and truck tires and can be used on uneven surfaces and rough and rugged terrain. They come in a solid form made of solid durable rubber, which makes them puncture resistant. Air pneumatic tires are air filled.
Forklift trucks are grouped according to their size, weight limit, operational terrain, and power supply. The Occupational Safety and Health Administration (OSHA) has developed seven classifications or categories for forklift trucks based on those factors. Each classification requires operators to be certified for the class they operate.
Class 1 forklifts are electrically powered by industrial batteries and electric motors. They can have pneumatic or cushion tires with three or four wheel designs. The lifting capacity for class 1 forklift trucks is between 1.5 tons to 4 tons.
Class 2 forklifts also run on electric motors and are made for narrow spaces. They have a lifting capacity of 1.5 tons to 2.5 tons.
Class 3 forklifts are designed to lift loads a small distance off the surface and are stand up forklifts where the operator stands next to the truck and uses hand controls. They are used for loading and unloading trucks and have a capacity of 4 tons.
Class 4 forklifts have cushion tires for warehouse use and where there are smooth and dry surfaces. They are gas powered forklifts with propane or diesel motors. Class 4 forklifts have a sit down design with a lifting capacity of 1.5 tons to 7.75 tons.
Class 5 forklifts have pneumatic tires and can lift very heavy loads between 1.5 tons to over 25 tons. They are powered by natural gas, liquid propane, or gasoline and can be used indoors or outdoors. Class 5 forklift trucks are the most common type of forklift in use and are sit down types.
Class 6 tractors are known as tuggers or tow tractors and are used for towing. They do not have forks and are a tractor type heavy duty vehicle that can be found at airports. Class 6 tractors can be electrically or internal combustion powered with a towing capacity of 1.5 tons to 3 tons.
Class 7 forklifts have large tractor type tires and are designed for heavy, rugged, and rough terrain use. They have diesel fueled engines and require special training for licensing and certification. Class 7 forklift trucks have a capacity of 3 tons to 6 tons or more. Many models of class 7 forklifts are equipped with telescoping booms to enhance their reach.
Forklift trucks are a ubiquitous piece of heavy duty equipment found in a wide range of industries. They are a rugged and durable method for moving goods, products, supplies, parts, and components from one location to another without damaging facilities or harming staff. Introduced in the middle of the first industrial revolution, forklifts have become necessary in the rapidly growing industrial world.
Regardless of their many values, it is important to select the right forklift to fit an application since ones that are too small can be damaged by over capacity lifting and ones that are too large can be wasted on light loads. There are three important factors to consider when choosing a forklift truck.
The type of load is the first consideration in the selection process since it will be the main factor in regard to how safely the forklift will be able to handle the workload. Multistage masts, articulated movement, and heavy duty forks may not be necessary for a narrow aisle warehouse. Side loader forklifts or turret forklifts may be more suited for such conditions and have the right capacity.
Versatility is one of the reasons that forklift trucks have been used by industry for close to 200 years. There is a forklift to fit any lifting and loading conditions. Free lift multistage masts allow the flexibility for reaching extreme shelf heights in narrow aisles. Triplex swinging mast forklift trucks offer a great deal of freedom of movement and adjustment.
In many cases, the cost is the first factor that buyers use as the determining factor for the purchase of equipment. Although this is a necessary consideration, it cannot be the sole deciding factor. A key component of forklift use is safety since it is the means for lifting heavy loads without the need for manual labor. The two factors that need to be considered in the purchase of a forklift are the initial cost compared to the increased benefits over time. Amortized over years of use, a highly versatile and highly functional forklift truck will pay for itself in efficiency, improved product movement, and labor savings.
Forklift trucks are one of the most dynamic and useful tools for any operation. They smoothly, effortlessly, and safely minimize time on task and remove repetitive actions. Today’s forklifts make it possible to reach the highest shelf in a storage facility without endangering equipment or personnel.
Forklifts are compact machines that can work indoors or outdoors, in cramped and narrow spaces, and on rough and rugged terrain. They can lift the heaviest of loads and safely place them with precision and ease. The capacities of forklifts range from a little over a ton to more than 12 tons, making it possible to select the perfect forklift for the conditions and loads.
Proper and regular maintenance is an essential part of the care for any type of heavy duty machinery. In the case of a forklift, maintenance and upkeep are easily completed and ensure a forklift’s years of usefulness.
During the first industrial revolution, unsafe conditions were the main cause of worker deaths since there was little protection from the dangers of equipment and lifting was handled manually. The inception of the forklift was a major step in the efforts to protect workers and save their lives. This foundational principle is still the hallmark for the use of forklifts. In some companies, attempting to lift a heavy load without a forklift can lead to a reprimand or disciplinary action.
Every company has a set of standards for forklift operations and requires all forklift operators to be certified. Although there are standards established by OSHA, manufacturers have developed their own requirements that exceed those from OSHA and specifically fit their manufacturing processes.
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