Understanding Pneumatic and Hydraulic Lifts

Examples of the types of lifts available, including boom, scissor, and vertical mast lifts.

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Pneumatic and hydraulic lifts are two types of lifts that are widely used throughout industry due to their high load capacities, large extension ranges, and environmental versatility. While several classifications of lifts are available, in the majority of residential, commercial, and industrial applications, the lifting action is typically performed by a pneumatic or hydraulic mechanism. However, mechanical lifts are also available for applications unsuited for pneumatic or hydraulic lifts, such as those requiring limited-range—but precise—movement and quiet operation.

Beyond classification by the lifting mechanism, some of the other design options for lifts include an electric, gas, diesel, or propane power system, portable or stationary, articulating or telescopic, trailer- or truck-mounted, and light or heavy-duty. Based on these various design characteristics, a diverse selection of these lifting devices is available for a wide range of residential, commercial, and industrial applications, including accessibility, maintenance and repair, material handling, personnel moving, transportation, and unloading and loading.

While several varieties of lifts are available, this article focuses on pneumatic and hydraulic lifts, exploring the various designs and types available and explaining their respective functions and mechanisms. Additionally, this article outlines the selection considerations and common applications for each type of lift.

The Hydraulic Lift: What is (and isn’t) a Lift?

Before going into the details of and differences between the specific classifications of pneumatic and hydraulic lifts, first an understanding of what lifts are—specifically what can and cannot be considered a lift—must be established.

There are several different types of lifting equipment and devices available with similar mechanisms, functions, and names, including lifts. The term “lifts” is an umbrella term referring to equipment used primarily to raise and lower objects, such as goods, cargo, people, and machinery, for residential, commercial, and industrial applications. Besides lifts, other lifting equipment and devices also include hoists, winches, cranes, elevators, actuators, positioners, manipulators, lifters, and jacks. As described below, each is capable of lifting an object, but their exact mechanism, function, or industrial application may differ from that of lifts, resulting in their classification as a separate category of lifting equipment.

An electric hydraulic work positioner

Image credit: Unidex Inc.

Direction and Application of Lifting Force

Regardless of the type of lift, the force which lifts the object is applied from below, pushing the object upward from the ground. This origin and direction of force distinguish them from other lifting devices, such as hoists, winches, cranes, or elevators, where the lifting force typically originates above the object being lifted, pulling the object upward from the ground. In either case, the application of force allows for vertical—and in some cases, horizontal—displacement of the object, with the difference being whether the force results in a pushing or pulling motion.

Electric cable hoist lifts steel pipes.

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Scale and Magnitude of Displacement

Lifts generally operate on the macro-level scale, meaning they are used for lifting applications involving larger objects and displacing objects over more significant distances than other devices, such as actuators and positioners. While these latter devices can produce pushing forces, some of their applications are on the micro-level scale, involving smaller objects and producing relatively small displacement (often measured in microns). Additionally, lifts may incorporate actuating components into the lifting mechanism design to help produce the lifting force, but actuators, in and of themselves, are not lifts. Manipulators—while capable of operating on the macro-level scale—also typically do not move objects over large distances either, only changing the orientation of the object at its original location or moving the object within a small, contained area.

A precision ball screw actuator.

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Characteristics of the Lifting Components

Lifters—although nearly identical in name—are in a category of lifting equipment separate from lifts. In order to lift an object, lifts employ a base component (such as a platform or arms), on which the object rests, and a mechanism, which produces an upward pushing force on the object. Together, these lift components enable the vertical displacement of the object. Lifters can also cause the vertical displacement of an object. However, lifters, such as those utilizing vacuum pressure or lifting magnets, typically must be physically attached to the object for the mechanism to lift it via a pulling motion or, in the case of handheld lifters, require the user provide the force which lifts the object themselves rather than employing a lifting mechanism.

An electromagnetic lifter.

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Industrial Delineation of Lifting Equipment

Jacks, such as bottle jacks and drum jacks, can employ similar lifting mechanisms and are used in similar applications to that of lifts. However, despite these similarities, industrial standards typically classify jacks in a category of lifting equipment and devices separate from that of lifts. Therefore, the following article will not cover jacks.

A hydraulic car jack.

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Pneumatic vs. Hydraulic Lifting Mechanisms

Now that a basic understanding of what lifts are and are not has been established, greater description and detail can be given to some of the more specific classifications—i.e., pneumatic and hydraulic lifts.

Lifts employ a variety of actuating components and mechanisms to produce the upward pushing force necessary to lift an object. The three principal actuator types integrated into lift designs are pneumatic, hydraulic, and mechanical, with the first two serving as the most common mechanisms employed.

Pneumatic Lifts

Pneumatic lifts employ a lifting mechanism which incorporates a hollow cylinder and piston. An external motor or pump moves the piston within the cylinder, increasing the internal air pressure and causing the cylinder to move along the axis of the piston. The cylinder’s motion along the axis creates a linear force which is then used to extend the lift components, raising or lowering the object.

The advantage of employing pneumatic lifts is their collective versatility. Many pneumatic lift models do not require electricity and can be used in a variety of applications, including extreme temperatures and explosion-prone areas. Additionally, pneumatic mechanisms are inexpensive compared to electric and hydraulic ones, are accurate to within in +/-0.1 in., and can generate lifting forces on the order of tens of thousands of pounds force (lbf). 

Despite these advantages, pneumatic lifts are limited both by their actuator size and compressor requirements. Throughout the lifting application, operating pressure must be maintained which make pneumatic lifts less-efficient than other types of lifts. This constant pressure requires the constant flow of compressed air, which also increases the overall operating costs. Additionally, pneumatic actuators are typically sized for a specific application, which limits the versatility of a particular lift to the specifications and requirements of the original application.

Hydraulic Lifts

Hydraulic lifts employ a lifting mechanism similar to that of pneumatic lifts except instead of compressing air, the hydraulic mechanism compresses a liquid (i.e., hydraulic oil) to increase the internal pressure within the cylinder. Like in pneumatic lifts, the increase in internal pressure causes the linear motion of the actuating cylinder which, in turn, raises or lowers the platform and, consequently, the object.

Hydraulic lifting mechanisms are capable of producing up to and greater than 25x the force produced by comparable pneumatic lifting mechanisms. Additionally, they can hold both force and torque constant without the need for a continuous fluid flow as with pneumatic mechanisms.

However, unlike pneumatic and electric lifting mechanisms, hydraulic mechanisms have greater environmental impact risks as the components contain hydraulic fluid, which can be detrimental to the environment in the event of a leak. Additionally, hydraulic lifting mechanisms involve several components and parts, leading to a larger space requirement.

Alternative Lifting Mechanism Solutions

For applications unsuitable for pneumatic and hydraulic lifts, mechanical lifts provide an alternative lifting solution. These lifts utilize several different mechanical components depending on the model, including hand cranks, ball screws, lead screws (or power screws), and rack and pinion drives, and can be either hand-operated or powered by an electrical motor. In any of type of mechanical lift, the lifting mechanism functions by translating the radial motion of the components into linear motion which is then exhibited as the extension of the lifts components and raising or lowering of the intended object.   

Electric-powered mechanical lifts offer the greatest control, precision, and accuracy, as well as allow for the lift capabilities to be scalable and repeatable.  Compared to pneumatic and hydraulic mechanisms, electric lifting mechanisms produce less noise and present fewer environmental risks due to their lack of fluids. However, electrical lifting mechanisms are typically more expensive and their lifting capabilities—e.g., load capacity, speed, etc.—are limited by the chosen motor, device lifespan, and suitable applications. 

Table 1 – Advantages and Disadvantages of Lifting Mechanisms

Lifting Mechanism

Advantages

Disadvantages

Pneumatic

  • High accuracy
  • Generates large lifting forces
  • Overall operating environment versatility
  • No environment risks (from leaks)
  • Lowest initial cost
  • Requires constant flow/operation
  • High operating costs
  • Limited individual versatility (by actuator size)

 

Hydraulic

  • Produces greater force than pneumatic
  • Constant force and torque
  • Does not require constant flow/operation
  • Risk of environmental leaks
  • Larger area footprint

 

Mechanical

  • Greatest control, precision, accuracy
  • Scalable operations
  • Quietest operation
  • No environment risks (from leaks)
  • More expensive
  • Lifting capability limited by motor
  • Motor fatigue from use
  • Not suitable for hazardous or flammable applications

Lift Design Characteristics

As outlined above, all lifts are capable of producing an upward pushing force which, when applied to an object, vertically displaces—i.e., raises or “lifts”—it.  Beyond these shared qualifications, several options for lift design characteristics are available to suit a wide range of applications, including, as mentioned previously, the type of lifting mechanism employed. Besides this characteristic, the other main design options which an industry professional or procurement agent may consider include:

  • Type of power source
  • Mobility
  • Maneuverability

Lift Power Source

The power source of a lift typically takes the form of an engine (except for in electric-powered models) and provides the necessary power which runs the lifting mechanism (pneumatic, hydraulic, or mechanical), and, if applicable, the drive system. There are five main types of power sources employed by lifts:

  • Electric
  • Diesel
  • Gas
  • Dual fuel
  • Hybrid

Electric-Powered Lifts

Electric-powered lifts are available in both stationary and mobilized models, and, depending on the model, utilize AC or DC power. Employing a combustion engine-free design powered either by plug-in units or batteries, electric-powered lifts are the only type of lift offering quiet, emission-free operation, which makes them suitable for indoor use. As lift batteries are rechargeable, the long-term fuel costs for battery-powered lifts are typically less than fuel-powered lifts. Additionally, the lift design allows for more compact construction compared to other powered designs, enabling for easier navigation, maneuverability, and storage in enclosed or limited-space applications.  

While electric-powered lifts offer some advantages in regards to environmental impact, long-term cost, and mobility concerns, they are limited with respect to platform size, vertical and horizontal extension, and load capacity. Battery-powered lifts also require the integration of a battery charging station, and battery replacements every 2–5 years—depending on use, condition, and maintenance—with prices ranging from $200–$500. While long-term costs of these lifts are typically cheaper than fuel-powered lifts, initial and maintenance costs are relatively high.

Diesel-Powered Lifts

Unlike electric-powered lifts, diesel-powered lifts are not emission-free. However, newer diesel engine technology, such as Tier II, III, and IV engines, offers high-performance value, longer operation periods, and lower levels of exhaust emission compared to older diesel-engine models, with some models capable of producing fewer emissions than even dual fuel or gasoline-powered lifts. Typically, these lifts also have larger platform areas, greater vertical and horizontal extension ranges, higher load capacities, and better traction than electric-powered lifts. These advantages make diesel-powered lifts suitable for use outdoors and for rugged-terrain applications, such as construction and industrial job sites.        

While newer models produce fewer exhaust emissions, in general, diesel-powered lifts produce more emissions and noise than electric-powered lifts and other engine-powered lifts, such as gas or LP lifts. These limitations make them generally unsuitable for most indoor applications.

Additional limitations surrounding diesel-powered lifts include initial and overall costs. While the cost of the diesel fuel necessary to run a diesel-powered engine is relatively inexpensive—ranging around USD 3–4—the diesel engine itself typically incurs greater investment and maintenance costs than other power sources for lifts. Some diesel-powered models are available at $5,000 premiums compared to gas-powered models, with an estimate in the thousands of dollars regarding the additional cost of oil changes, component replacements, and maintenance and repair over the engine’s lifespan.

Gas-Powered Lifts

Gas-powered lifts, like diesel-powered lifts, employ an internal combustion (IC) engine which produces emissions throughout operation regardless of fuel type—although some fuel types may produce fewer emissions than others during the combustion process. While, compared to electric-powered lifts, these lifts are less environmentally-friendly, they are also capable of employing larger platforms, lifting larger loads, and extending to greater heights and lengths. Several types of gases are used in gas-powered lifts, including gasoline, natural gas, and propane. Depending on the requirements and specifications of the lifting applications, each gas type offers its own advantages and limitations.

Gasoline: Due to the limited availability of refueling stations and the development and the rising popularity of liquid propane (LP) and dual-fuel-powered lifts, gasoline-powered lifts are rarely used. However, if refueling stations are readily available and easily accessible, gasoline-powered lifts can be comparable to other engine-powered lifts. Additionally, the gas-powered design offers greater rearview visibility compared to LP-powered designs and more power, faster travel, and greater platform lift/lower speeds compared to diesel-powered designs.

Natural gas: Similar to gasoline-powered lifts, lifts which employ compressed natural gas (CNG) require ready and easy access to refueling stations to be a cost-effective lifting solution. However, the high cost of the infrastructure necessary for CNG refueling stations—including land, equipment, maintenance, and installation—and the difficulty of obtaining the necessary permits and the gas supply typically make CNG power sources unsuitable for the budgets of most lifting applications. 

Given an adequate and accessible CNG refueling infrastructure, compared to other fuels, CNG offers a more environmentally-friendly alternative. Combustion processes which utilize CNG typically produce fewer emissions and, in the event of a gas leak, CNG dissipates into the atmosphere as non-toxic compounds—i.e., water vapor and carbon dioxide. CNG-powered lift designs also do not require the removal of the CNG tank during the refueling process, which allows for less downtime and operator involvement.

Propane: Lifts which employ liquid petroleum gas, also known as liquid propane (LP), offer the lowest initial cost, as LP tanks can be purchased and stored in advance. Replacement of empty tanks is also relatively quick, allowing for less downtime between lifting applications. LP-powered lifts are suitable for both indoor and outdoor applications.

Dual-Fuel-Powered Lifts

As indicated by the name, dual fuel-powered lifts employ two different types of fuels—gas and diesel. The advantage of employing these types of lifts is their high fuel efficiency compared to other fuel-powered lifts. Additionally, newer dual-fuel-powered models are capable of producing greater horsepower than diesel-only models. However, the cost of the fuel used for dual-fuel lifts (typically liquid propane) is highly variable with costs ranging between USD 2–5 per gallon.

Hybrid-Powered Lifts

Hybrid-powered lifts employ a combination of the technology from two different types of power sources (typically electric and diesel). Depending on the type of hybrid model—i.e., parallel or series—either or both power sources can power the lift, or the combustion engine acts as a charging generator for the lift’s batteries which power the majority of the lift’s functions, respectively. While series models are less expensive and employ a more compact design than parallel models, parallel models can produce greater power and offer greater flexibility and security due to the power redundancy.

In general, hybrid lift models are capable of operating under extended use and heavy-duty cycles and suitable for both indoor and outdoor applications. The ability to switch to electric-only power, allows for greater operating environment versatility, especially for indoor applications where exhaust emissions must be limited and for outdoor applications where refueling stations are not easily accessible. These advantages come at a cost, however, as hybrid-powered lifts are typically more expensive than comparable diesel or gas-powered models.

Table 2 – Advantages and Disadvantages of Lift Power Sources

Power Source

Advantages

Disadvantages

Electric

  • No exhaust emissions
  • Quieter operation
  • Compact design
  • Suitable for limited and enclosed spaces
  • Long-term fuel costs lower than fuel power sources
  • Limited platform area, extension range, and load capacity
  • Integration of battery charging station
  • Battery replacement every few years
  • High cost of batteries and chargers
  • Not suitable for wet environments

Diesel

  • Newer models produce fewer emissions
  • Greater platform area, extension range, and load capacity than electric
  • Suitable for outdoor and rugged-terrain
  • Diesel costs are lower than other fuels
  • Has exhaust emissions
  • More noise than electric
  • High initial investment and maintenance costs

Gas

-

-

Gasoline

  • Greater rearview visibility than LP
  • More power and faster speeds than diesel
  • Has exhaust emissions
  • Limited refueling station availability

Natural Gas

  • Fewer emissions than other fuels
  • Less environmental impact (w/ leaks)
  • Less downtime and operator involvement during refueling
  • Has exhaust emissions
  • Limited refueling station availability
  • High cost of refueling infrastructure

Propane

  • Lowest initial cost
  • Easy fuel tank replacement
  • Suitable for indoor and outdoor use
  • Has exhaust emissions
  • Tanks obscure rearview visibility

Dual-Fuel

  • High fuel efficiencies
  • Greater HP than diesel
  • Has exhaust emissions
  • Variable cost of fuel

Hybrid

  • Suitable for indoor and outdoor use
  • Operating environment versatility
  • Suitable for extended use and heavy-duty applications
  • Higher costs than diesel and gas models

Lift Mobility

Depending on the type employed and the specifications of the lifting application, lifts are available in stationary or mobile models.

Stationary models may be fixed into position, such as in the case of dock lifts or accessibility lifts, or portable but operate within the confines of a singular location throughout the lifting application. In the latter case, the lifts are not self-propelling and require an auxiliary vehicle to tow or haul them into place, such as trailer-mounted or truck-mounted lifts. The advantages of stationary lifts are their lack of fuel costs and their more compact design (both owing to the fact that they do not contain their own transport motor). Some models also integrate hydraulic outriggers which assist in setup and leveling.  

Mobile lifts are self-propelled which allows operators to adjust their positioning when necessary. They are available with several types of drive systems, including:

  • 2-wheel drive
  • 4-wheel drive
  • Track drive

2-wheel Drive: Lifts with 2-wheel drive are more compact and typically used in indoor applications. However, equipped with rugged-terrain wheels, they can also be used outdoors. These lifts are limited in their maximum load capacities, extension range, and maneuverability, but they make up for these disadvantages with faster charging or refueling times and extended operating times.

4-wheel Drive: 4-wheel drive lifts are the standard for most industrial and construction job sites as they offer larger platform areas, larger load capacities, and greater extension ranges. Other design characteristics of 4-wheel drive lifts include greater traction control, leveling capabilities, and faster lifting speeds.

Track Drive: Track drive lifts employ a combination of the technology from stationary and mobile lifts—i.e., their hydraulic leveling and self-propelling capabilities, respectively. Available with rubber-free or rugged-terrain wheels and 4-wheel drive, these lifts are suitable for both indoor and outdoor applications.

A four-wheel drive forklift.

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Lift Maneuverability

There are several design options available for lifts that can improve their maneuverability during lifting applications, especially for limited access or confined spaces. Articulating and telescopic boom designs are two of the most commonly employed.

Constructed of multiple hinged and jointed sections, articulating boom arms can bend and reach around and over obstructions and obstacles to lift the platform or object into the proper position. Additionally, articulating lifts typically incorporate a turntable component, allowing for the full rotation of the lift arm. Together, these two design elements allow these types of lifts to offer a wide range of working heights and a high degree of flexibility.

Elevated aerial platforms on articulating boom lifts.

Image Credit: SteveWoods/Shutterstock.com

As indicated by the name, telescopic boom arms extend much like telescopes, with multiple sections that extend and retract out of and into each other. Unlike articulating arms, telescopic arms extend straight out which limits their ability to lift a platform or object if the pathway is obstructed or otherwise restricted. Additionally, lifts which incorporate telescopic arms typically have smaller platforms than articulating arm lifts. However, most telescoping models are still available with full rotation capabilities, as well as offer greater extension rangers than other lift types.

Telescopic boom lift with extended arm and elevated aerial platform.

Image Credit: Lloyd Paulson/Shutterstock.com

Other Lift Design Characteristics

Besides the design characteristics mentioned above, there are several other options an industry professional or procurement agent may consider when designing and choosing a lift for their particular lifting application. Some of the other design options available include tilt capabilities to improve maneuverability and flexibility, railings for operator safety, hydraulic outriggers for additional stability, and non-marking or rough-terrain tires for indoor and outdoor use, respectively.

Types of Lifts

Employing the design characteristics indicated above, there are several different variants of lifts available. Some of the more common types employed for residential, commercial, and industrial applications include:

  • Boom lifts
  • Vertical mast lifts
  • Scissor lifts
  • Forklifts
  • Vertical platform lifts

Boom Lifts

Boom lifts are aerial lifts used to raise and move personnel to the proper elevation and position within a job site. Constructed of one or more extendable boom arm components with an attached aerial platform and actuating components (which provide the necessary driving force for the articulation or extension of the components), these lifts offer some of the greatest vertical and horizontal displacement capabilities with maximum extensions ranging between 20–100+ ft. The main types of boom lifts available include articulating (also known as knuckle) and telescopic boom lifts with options for stationary or self-propelling capabilities. Some of examples of the boom lifts available include trailer-mounted or truck-mounted boom lifts and cherry pickers (also referred to as bucket trucks).

Some of the typical applications for boom lifts include industrial and construction job sites, as well as agriculture, landscaping, utility, and maintenance and installation work.

Vertical Mast Lifts

Unlike boom lifts, vertical mast lifts (also referred to as vertical lifts or personnel lifts) are aerial lifts which are generally only capable of vertical displacement and do not allow for much in the way of horizontal extension. Although, depending on the model, these lifts can have self-propelling capabilities which allow operators to adjust the position of the lift on the ground, and, consequently, the relative position of the platform. The typical construction design features an aerial platform attached to a single vertical, telescopic arm (i.e., mast) and actuating components, but some models may also incorporate an articulated arm component.

Vertical mast lifts offer a more lightweight design than other types of lifts which allows for greater maneuverability but also limits the maximum size of the work platform and load capacity. These lifts are suitable for indoor and limited-space applications which only require vertical extension, such as warehousing, inventory management, and maintenance and installation.

Illustration of a vertical mast lift with an articulating arm component.

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Scissor Lifts

Like vertical mast lifts, scissor lifts are only capable of vertical displacement. These lifts employ a pantograph mechanism which elongates when an inward force is applied to the sides of the mechanism and shortens when an outward force is applied. As the mechanism elongates and shortens, it applies an upward force to the attached aerial platform, causing the platform to rise and fall, respectively. Depending on the model, hydraulic, pneumatic, or mechanical actuating components are employed to provide the driving force for the elongation and shortening of the pantograph mechanism. Other design options available for scissor lifts include safety controls and railings, self-propelling capabilities, and articulating, tilting, or rotating platforms.

Scissor lifts typically offer high load capacities and employ a much larger platform than other types of lifts, which allows for multiple or heavy objects and personnel to be moved and positioned in a job site at once. However, as these lifts are limited to vertical displacement, they must be positioned directly below the desired usage point at the job site which may be difficult in rugged-terrain or limited-space areas. Suitable for heavy-load and heavy-duty lifting operations, typical scissor lift applications include construction, maintenance, repair, and installation. While scissor lifts can be motor-driven, they are also available in permanent and semi-permanent installations.

Illustration of a scissor lift.

Image Credit: Andrio/Shutterstock.com

Forklifts

Forklifts, also referred to as called forklift trucks and pallet lifts (due to their common employment in pallet handling applications), are suitable for lifting objects from the floor to the proper height and position for work, storage, transportation, or loading and unloading. In addition to the fork and carriage (i.e., the frame to which the forks attach) components, the typical forklift design employs lifting mechanisms similar to that of the previously mentioned types of lifts, such as forklift booms or vertical masts. Depending on the model, mechanical, pneumatic, or hydraulic actuating components power the forklift’s lifting capabilities, which can be limited to vertical displacement or include both vertical displacement and horizontal extension. Additional design characteristics available for forklifts include manual or motorized drive, counterbalancing, and the integration of other forklift accessories.

As defined by the Industrial Truck Association (ITA), there are eight classifications of industrial lift trucks (which includes forklifts), ranging from Class I to Class VIII. Each class is representative of a specific type of lift truck and its characteristics. For example, a three-wheeled, electric-powered forklift is classified as a Class I, while a gas-driven forklift truck with pneumatic tires and a seated operator cab is classified as a Class V. Some of the other types of forklifts available include truck-mounted forklifts and rugged-terrain forklifts.

Table 3, below, provides a short description of the different classes of lift trucks available.

Table 3 – Industrial Lift Truck Classifications

Note: Classification breakdown courtesy of OSHA.gov

Class

Short Description

Characteristics

I

Electric Motor, Rider Trucks

  • Electric motor
  • 3 or 4 wheels: cushion or pneumatic tires
  • Rider design: sit down or stand up styles

II

Electric Motor, Narrow Aisle Trucks

  • Electric motor
  • Suitable for narrow aisles and very narrow aisles
  • Extended reach or swing mast capabilities

III

Electric Motor, Hand or Rider Trucks

  • Electric motor
  • Walk behind or stand up rider design
  • Can have counterbalancing, depending on model
  • Includes pallet jacks, tow tractors, and low/high lift platforms

IV

IC Engine, Solid/Cushion Tire Trucks

  • Internal combustion engine
  • Solid (cushion) tires
  • Rider design: sit down style
  • Typically counterbalanced

V

IC Engine, Pneumatic Tire Trucks

  • Internal combustion engine
  • Pneumatic tires
  • Rider design: sit down style
  • Typically counterbalanced

VI

Electric or IC Engine Tow Tractors

  • Also called tuggers
  • Electric motor or internal combustion engine
  • Rider design: sit down or stand up styles

VII

Rough Terrain Forklift Trucks

  • Typically internal combustion engine
  • Pneumatic tires
  • Suitable for rugged-terrain/outdoor use
  • Three basic styles: vertical mast, variable reach (boom), and truck/trailer-mounted

VIII

Electric/IC Engine Personnel and Burden Carriers

  • Electric motor or internal combustion engine
  • Suitable for carrying and transporting personnel and small loads
Illustration of a forklift carrying a load of boxes.

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Vertical Platform Lifts

Vertical platform lifts employ a base or platform component affixed to one or more vertical masts (or posts). As the mechanical, pneumatic, or hydraulic actuating components are engaged and disengaged, the platform raises and lowers. Some examples of these types of lifts include dock lifts, truck tailgate lifts, stage lifts, and accessibility lifts.

Dock lifts, truck lift gates, stage lifts, and accessibility lifts offer similar functions for different applications. Each of these lifts is capable of providing vertical displacement to—i.e., raising or lowering—objects, people, or equipment to bring them to the proper height for loading or unloading. Typically, these lifts are permanently or semi-permanently installed into place, either included as an amenity or fixture of the building (in the case of dock lifts, stage lifts, and accessibility lifts) or attached as a component of the vehicle or truck (in the case of lift gates).

The applications for vertical platform lifts generally have smaller vertical lift requirements than the applications for other types of lifts as vertical platform lifts are only employed to bring something either level to the ground or level to a slightly elevated surface, such as the truck bed or loading dock.

An empty loading dock lift.

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Additional Lift Types

Lifts are employed in a variety of industrial, commercial, and residential applications. Consequently, there are several variants of lifts available, each suitable for the requirements and specifications of a particular application. Beyond the types already mentioned above, other types available include mezzanine lifts, two-post and four-post automobile lifts, and scissor lift tables.

Lift Selection Considerations

While there are a wide variety of lifts available, the suitability of each type (and its design) for raising and lowering an object, person, or equipment is dependent on the specifications and requirements of the application. Those factors largely determine the optimal design of the lift.

Some of the factors that industry professionals should keep in mind when specifying or choosing a lift include:

  • Application
  • Platform size
  • Rated load capacity
  • Stroke
  • Lift movement
  • Personnel certification
  • Lifecycle costs

Application: The intended application and its environmental conditions influence the optimal type and design of the lift and its components. For example, in uneven ground or rugged-terrain environments, hydraulic outriggers or rugged-terrain wheels may need to be incorporated into the lift design to assure stability. Tables 1 and 2 also list some of the application and environmental concerns surrounding each lift design characteristic. Some examples from these tables:

  • Mechanical lifts may not be suitable for highly flammable applications due to the risk of fire or explosion
  • Electric-powered lifts may not be suitable for outdoor or wet environments due to the risk of electrical component damage
  • Motor-driven lifts may not be suitable for indoor applications due to the exhaust emissions

Platform Size: The size of the object or equipment and the personnel or workspace requirements determine the dimensions—i.e., length and width—of the lift’s platform component.

Rated Load Capacity: The total weight requirements of the objects, equipment, and personnel determine the necessary load capacity of the lift. In lifts, the rated load capacity, or lift capacity, is the maximum load (i.e., weight), as determined by the manufacturer, that is safely supportable by the particular lift. Rated load capacities are determined based on a specific load center, meaning that the weight is safely supportable by a lift given that the load is positioned and distributed on the lift platform as specified by the manufacturer.

Stroke: The lifting and working height requirements of a lifting application—i.e., how high an object or person must be lifted—determine the necessary stroke length of the lift. In lifts, the stroke length is the distance traveled by the actuating components from fully-closed to fully-open which correlates to the distance traveled by the lift platform from fully-lowered to fully-raised, respectively. Therefore, the stroke length determines the maximum height a lift can raise an object or person.

Movement: The movement, mobility, and maneuverability requirements of a lifting application determine some of the design characteristics of the lift. For example, the purchasing and procurement agent needs to consider whether the lifting application requires only vertical movement or both vertical and horizontal movement. If the lift will be used for both vertical and horizontal extension, design consideration needs to be given to the farthest possible horizontal position of the load relative to the lift’s base as the load’s positioning affects the lift’s load capacity and stability. Additionally, if the application requires self-propelling and self-positioning capabilities, then the integration of a drive system may be necessary, and if the application requires lifting equipment or personnel around and over obstructions and obstacles, then the lift may need articulating boom arms.

Personnel Certification: If certain lifts, including aerial lifts and scissor lifts, are used in a workplace environment, then, as per OSHA requirements, the employees operating them are required to receive the proper lift operator training and certification. The training details the proper method of using, moving, operating, maintaining, and repairing the lift in order to prevent workplace accidents or operator injury.

Lifecycle Costs: The cost of a lift includes not only the initial price of the equipment, but the installation (if applicable), maintenance, repair, and operator training costs over the lift’s lifespan as well. While it is necessary to choose a lift which fulfills the requirements of the lifting application, it is also important to keep in mind the overall costs of the chosen lift to better determine the long-term value of the investment. Companies which do not have the budget necessary for the large initial purchasing investment or require year-round lift use have the option to forgo purchasing a lift and instead may lease or rent one as needed.  

Applications of Lifts

Scissor and articulating lifts for industrial applications.

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Lifts have a variety of uses in residential, commercial, and industrial applications. There are several types and variants of lifts available, with the characteristics of each making it suitable for the requirements and specifications of a particular application. Lifts, especially aerial lifts, are commonly employed throughout industry, especially in construction, manufacturing, and material handling. Some lifts, such as scissor lifts, forklifts, and dock lifts find application in both industrial and commercial environments, while other lifts, such as accessibility lifts, are used in more residential applications.

Table 4, below, indicates some of the common industries and applications of the types of lifts previously mentioned.

Table 4 – Industries and Applications of Lifts by Type

Type of Lift

Common Industries and Applications

Boom Lifts

  • Industrial and construction job sites
  • Agriculture
  • Landscaping
  • Utilities management
  • Maintenance, repair, and installation work

Vertical Mast Lifts

  • Indoor and limited-space material handling
  • Warehousing
  • Inventory management
  • Maintenance, repair, and installation work

Scissor Lifts

  • Industrial and commercial material handling
  • Heavy-load and heavy-duty lifting
  • Industrial and construction job sites
  • Maintenance, repair, and installation work

Forklifts

  • Industrial and commercial material handling
  • Warehousing
  • Inventory management
  • Manufacturing
  • Industrial and construction job sites

Vertical Platform Lifts

-

Dock Lifts

  • Industrial and commercial material handling
  • Loading and unloading

Truck Tailgate Lifts

  • Industrial and commercial material handling
  • Loading and unloading

Stage Lifts

  • Commercial material handling
  • Entertainment and event facilities
  • Stages
  • Orchestra pits

Accessibility Lifts

  • Commercial and residential applications
  • Hospitals and nursing homes
  • Emergency and accessible vehicles
  • Entertainment and event facilities
  • Workplace facilities

Mezzanine Lifts

  • Industrial and commercial material handling
  • Warehousing
  • Inventory management
  • Storage

Two-post/Four-post Lifts

  • Automotive repair

Scissor Lift Tables

  • Work object and equipment positioning

Summary

This guide provides a basic understanding of pneumatic and hydraulic lifts, the designs and types available, their applications, and considerations for use.

For more information on related products, consult Thomas guides and white papers or visit the Thomas Supplier Discovery Platform, where you will find information on over 500,000 commercial and industrial suppliers.

Sources

  1. https://homesteady.com/list-5814525-types-scissor-lifts.html
  2. https://sciencetrends.com/the-formula-for-work-physics-equation-with-examples/
  3. https://www.liftandaccess.com/article/hello-hybrid-powered-aerial-lifts
  4. https://safetyresourcesblog.files.wordpress.com/2014/11/aerial-and-scissors-lift-training-program.pdf
  5. https://www.osha.gov/SLTC/etools/pit/forklift/types/classes.html
  6. https://www.unidex-inc.com/blog/hydraulic-lifts-a-guide/

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