There are three main types of aerial work platforms: boom lifts, scissorlifts, and mechanical lifts. They can be operated with hydraulics, pneumatics, or mechanically via screws or a rack-and-pinion system. They are either unpowered units, requiring an external force to move them, self-propelled with controls at the platform, or mounted to a vehicle for movement.
Before aerial work platforms, all jobs requiring work at great heights had to be done on scaffolding.
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[edit] History
The aerial work platform invention is widely credited to John L. Grove, who was an American inventor and industrialist.[1] After selling his previous business, Grove Manufacturing, in 1967 he and his wife headed out on a road trip. During a stop at the Hoover Dam, Grove witnessed two workers electrocuted while working on scaffolding. Through this “tragic event” John Grove saw a large untapped market for a product that could put workers in the air more safely to perform construction and maintenance tasks.[2]
When Grove returned home from his trip, he formed a partnership with two friends, bought a small metal fabrication business, and began designing concepts for the aerial work platform. The company was named JLG Industries Inc., and with the aid of 20 employees it released its first aerial work platform in 1970.
Aerial work platforms eventually began being designed with a variety of additional features. Many are now equipped with electrical outlets, compressed air connectors, and various other adaptations for tools.
JLG introduced its line of Workstation in the Sky models, which were designed with features for specific trades.
"Tradesmen are using AWPs to lift more than people. They need to put tools and materials up in the air, so why not give them an AWP with some tools they need—a rack for securing glass or handling duct, or a platform that has electrical outlets, a welder, or even a masonry saw—built right in?"[3]
[edit] Features/How it Works
[edit] Boom Lifts
There are two basic types of boom lifts: straight boom lifts and articulated boom lifts. These units are often hydraulically powered.
[edit] Straight
Straight boom lifts are generally used for jobs that require a high reach without obstructions. The machine’s turntable can rotate 360 degrees with an extendable boom that can be raised vertically to below horizontal. The operator can maneuver and steer the vehicle while the boom is fully extended. It is available in gas, propane, or diesel-powered models with two or four-wheel drive.
[edit] Articulated
Articulated boom lifts are used for jobs that require reaching up and over obstacles to gain access to a job not easily approached by a straight telescopic boom. This lift is nearly identical to the straight boom lift in every aspect, except in the boom’s ability to articulate. Articulation points on the boom allow it to bend in any number of different directions enabling it to maneuver around various obstacles on a job site.
Boom lifts can be equipped with outriggers to stabilize a unit while the boom is fully extended.
[edit] Scissorlifts
Scissorlifts are designed for working on directly overhead projects as they only lift on a vertical plane. It consists of a series of linked, folding supports that crisscross in an “x” pattern. In order to raise the unit, pressure must be applied to the outside of the lowest set of supports, which elongates the crossing pattern, elevating the platform vertically. If the machine is hydraulically or pneumatically powered lowering of the platform can be achieved by simply opening a valve to release the pressure.
Scissorlift types can vary from electrical models designed for indoor use to rough terrain models for more rigorous construction needs. Rough terrain models are equipped with stronger, more reliable tires and are powered by gas or diesel motors.
[edit] Mechanical Lifts
Mechanical lifts are generally smaller models that use rack-and-pinion systems or screw threads to elevate the platform. They are limited in the amount of weight they can carry and the heights they can extend to. They are mainly used for indoor tasks like changing light bulbs.
[edit] Common Manufacturers
[edit] Additional Photos
