Compact cylinders are precision pneumatic actuators built to maximize productivity within a limited amount of space. Like all air cylinders, these mechanisms utilize pressure differentials in order to convert compressed air energy into mechanical energy. This energy is put to work in a number of industrial and commercial applications.
Automotive, building, construction, food processing and packaging, metal working, mining, construction, textile and forestry industries all utilize compact cylinders as actuators for valves, lift gates, hoists, machines, jacks, motors, doors and equipment components. Because these mechanisms use only compressed air to open, close, push, pull and lift variable loads, they provide an economic and environmentally friendly solution to many mechanical operations.
Compact cylinders provide even further benefits as they are often as much as 60% smaller than comparable traditional alternatives and are therefore easily integrated into pre-existing workspaces or areas where space is at a premium. The significantly smaller size corresponds to the stroke of the cylinder.
Stroke is a measure of the difference in length between fully extended and fully retracted piston positions. Smaller strokes also result in increased speed and efficiency as the pistons travel a shorter distance. As this is such an influential measure, compact actuators are sometimes referred to as “short stroke cylinders.”
While many compact cylinder models use traditional single acting and double acting cylinder designs, the majority are rodless cylinders. While traditional compacts are just miniaturized, rodless designs reduce size without decreasing capabilities by simply eliminating the need for room to fully extend the piston rod beyond the length of the shaft.
Rack and pinion or cable cylinders are among the most common types of compact actuators. Both types have circular or rectangular cylinder with an air valve, for inlet and exhaust, located at one or both ends. In a rack and pinion system, this shaft houses two pistons. A toothed rack and pinion are located between these pistons.
When air is introduced into either end of the closed cylinder, the corresponding piston pushes the rack in the opposite direction. The pinion rolls along the rack creating rotation. This movement is transferred from the pinion to a connected shaft that protrudes from the shaft and connects to the tooling or load. Four piston rack and pinion cylinders are available and function in the same manner but are cube shaped.
Alternatively, cable cylinders operate with a pulley system. A cable is connected to the central piston and extends out one end of the shaft where it winds around two or more pulleys before circling around through the other endcap. A carriage, to which the intended load is attached, is located in a fixed position on the exterior portion of the cable.
Compressed air forced into the cylinder moves the piston which in turn rotates the cable. As capabilities differ significantly, it is important to carefully compare compact cylinder capabilities to the requirements of a specific application.