Section 7 - Actuators

Abstract

This chapter focuses on actuators. Pneumatic cylinders are considered the most commonly found actuators. Pneumatic cylinders can be classified into various types, such as single-acting, double-acting, through-rod, tandem and duplex, cushioned, rotating, and miniature. A wide choice of mountings is available: foot mounting, pin end, neck and flange mounting, hinge brackets, spherical rod ends, and clevises. Pneumatic cylinders of these types are manufactured on similar lines to hydraulic cylinders, except for a difference in the materials of construction and the relative rod sizes due to the lower working pressures of compressed air. The choice of a cylinder appropriate for a particular operation is determined by the required force to be applied, the available air pressure, and the speed of operation. Most manufacturers of cylinders supply performance data as part of the specification, either in their literature or on a computer-readable disc. The installation of standard pneumatic cylinders follows a similar procedure to that of hydraulic cylinders and depends on the mounting style chosen. This can be decided while the layout is being arranged. With special cylinders such as rodless, the machine can be designed to take advantage of the special features of the cylinders and the manufacturer's instructions should be followed.