Scissor lifts are tools that are used to raise and lower objects.
Scissor lifts use linked, folded supports that, when extended, form
diamond shapes. Compared with other types of lifts, scissor lifts are
able to hold large, heavy loads and handle wider work areas. They are
among the most common types of hydraulic lifts.
Scissor lifts are used in a wide variety of applications, from lift tables that adjust their height to provide an ergonomic work surface to aerial lifts that transport workers and goods to otherwise unreachable heights. Scissor lifts have many uses in construction and maintenance jobs. Scissor lifts may be gas or electric powered. Rough-terrain scissor lifts, for example, are diesel powered and good for outdoor use, but cannot be used inside. For inside uses such as in factories and warehouses, electric scissor lifts are better choices because they produce no emissions and very little noise. Scissor lifts are used extensively in construction and building maintenance applications. They are also used in specialized contexts; in theatres and television studios, scissor lifts are used to rig lighting and set equipment. This work would be very difficult with ladders because of the limited movement they allow workers while hanging equipment.
Most scissor lifts are powered by compressed hydraulic fluid. Some scissor lifts are powered mechanically; such designs often feature geared lifting mechanisms like racks and pinions. Hydraulic lift systems, though, offer much higher load bearing capacity and can be more reliable than mechanical lift systems. A hydraulic lift system involves a complex of metal support systems, control panels and, most importantly, hydraulic cylinders. A hydraulic cylinder is made up of a reinforced, hollow enclosure, a collection of hydraulic fluid, pumps, reservoirs, pistons and a collection of seals and flanges. When compressed hydraulic fluid is forced into a cylinder, it forces the movement of a piston. The piston is connected to a rod, which is itself connected to a load bearing surface. In the context of scissor lifts, that rod is connected to a metal support, which, when subject to a forceful exertion, pushes on other metal supports and forces the uppermost load bearing surface of the lift to become elevated. Scissor lifts take their name from the way in which their supports open; they open and close in a way that resembles a pair of scissors. The force generated by the compressed fluid is enough to reliably lift and sustain the weight of the load bearing surface. This reliability and strength are the qualities that make scissor lifts attractive.
Scissor Lift - Autoquip Corporation