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Hoist atop an elevator. A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium.
A trapdoor or hatch is a sliding or hinged door that is flush with the surface of a floor, ceiling, or roof. [1] It is traditionally small in size. [ 2 ] It was invented to facilitate the hoisting of grain up through mills, however, its list of uses has grown over time. [ 3 ]
To lift a load, a separate line runs up and over the mast with a hook on its free end, as with a crane. [ 1 ] [ 2 ] Derricks are especially useful for high-rise rigging, jobs that cover a long period of time, or jobs when the impact to street or pedestrian traffic is a concern. [ 3 ]
An inflatable jack, lifting bag, or pneumatic lifting bag is an air bag that is inflated by compressed air (without a hydraulic component) in order to lift objects. The bag can be deflated to be reused later. The objects can be of a smaller load such as an automobile [10] or it can be a larger object such as an airplane. [11]
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This mechanism is used in devices such as lift tables and scissor lifts.Modern low-profile computer keyboards make an extensive use of it as well, installing each key on a scissor support to ensure their smooth vertical movement, allowing the use of a cheap and reliable rubber dome contact set, instead of expensive and complex array of mechanical switches.
The slab lifter uses two safety devices. Safety chains and a support bracket allow safe lifting of large slabs. This lifting appliance also has a safety locking device that is engaged when the gripping pads are activated by the weight of the stone. This prevents any jerking movement from releasing the stone.
A race car's body is designed to optimize downforce, but if that body is spun so air is flowing in reverse, lift is generated instead of countered. [2] The roof flaps' job is to disrupt that airflow and prevent lift. [5] The decision to implement a safety device to keep cars on the ground came after two crashes in 1993.