Personnel and Dual Rated Hoists:
Most personnel only hoists are of a mobile variety, which are different from semi-temporary construction hoist systems. Such equipment as scissor lifts, articulated boom lifts, and others are mobile man-lifts that can be operated around the site and lift personnel safely.
Most construction hoist systems that are large enough for personnel also double as a material hoist system. Thus they are qualified as Dual Rated hoists for both material and personnel transport up and down the job site.
Buck Hoists/Construction Elevators:
The most common names for Dual Rated hoists are buck hoists and construction elevators. Both names describe the same type of system, where a cage or enclosed platform—commonly referred to as a car—is lifted up and down a mast system using hydraulic energy, a gasoline engine, or electric power.
The mechanism responsible for the lifting motion of the hoist is a rack and pinion system. The pinion is a rotational gear that is typically powered by electric energy. It rotates along a rack which is a linear gear track. The result is the rotational motion translated into linear motion vertically along the rack. For decent, the use of mechanical brakes—either hydraulic or disc—is utilized to prevent freefall of the elevator car. On each construction hoist system, there is an emergency fail-safe brake that works on the principle of centrifugal action in case of a complete emergency. In the case of a power-outage there is a manual brake that can be used to gently bring the hoist down to the nearest unloading point. Each car has a system of double gates to ensure safety of personnel while transitioning from the car to the job site. There is also a foldable transition ramp between the car and working level to ensure safe transitions as well.
The overall structure of the construction hoist is supported through a heavy ballast at the base of the mast, with tiebacks connecting the mast to the erected structure at designed intervals. This requires that the structure be designed in a manner to sustain the lateral and vertical loads of the construction hoist before installation of the hoist system.
Most construction hoists are modular systems with prefabricated components that can arrive on site and have set installation instructions. For some unique projects that require custom lift capabilities, custom construction hoists can be manufactured and installed for an additional cost to the contractor.
Construction hoists come most often in one or two car options. When a two car option is utilized, one car is typically for personnel transport, while the other is for material only. With today’s advancement in technology, both cars can be automatically controlled much like an interior modern elevator. That is, the personnel and material cars can be called automatically with a push of a button, so that manpower is not required for an operator of the lift.
Most construction hoist companies provide a ‘turnkey’ service including: installation, supervision, operational training, and de-mobilization.
Construction elevators eliminate the need for a strenuous climb for everyday workers while providing necessary lifting power for materials around site. The result is higher moral of the workers on site and improved efficiency of construction. The hoists also provide a safer alternative to the daily climb of a worker, resulting in a safer working environment.
There are many manufacturers of construction hoists in the industry including: Champion, Böcker, Alimak Hek, Beta Max, Peco, Pega, USA Hoist, and Patent. Companies that provide installation and operational services include Safway, Metro Elevator, and GEDA USA.