Actuators are a fundamental part of so many areas of daily life that it is difficult to think of any domestic, commercial, or industrial process devoid of them. These devices allow an operator or an automated system to remotely switch on or off, move, or otherwise activate a secondary device. Actuators come in many sizes, shapes, output capabilities, and power sources, with some of the more common types being the small actuators used perform light-duty actuation. Perhaps the most widely encountered of these is the simple solenoid, although just about every type of actuator, including electromechanical, hydraulic, and pneumatic types, are well-represented in any small actuator line-up.
Wherever operator activation of devices is unsafe, inconvenient or not practical, one or other type of actuator is typically used. These devices are characterized by their ability to harness a source of input power and produce a remote working motion used to activate or move the device in question. Typical input power sources include electric motors and compressed gas in pneumatic actuators and oil in hydraulic variants. The output movement of most actuators is either linear or rotary with a wide variety of actuation lengths and power ratings. Some of the more commonly-encountered types are the small actuators used to perform light-load activation tasks.
It is almost impossible to accurately define a set of exact parameters to describe small actuators, as the smallest actuator of one type will dwarf the largest of another. Most actuator varieties do, however, feature very small models used to activate light loads. Certainly, the most common of these are the electromagnetic family, including solenoids and voice coil actuators which rely on the generation of a magnetic field around a coil to attract a moving plunger or armature. Most other electric or electromechanical actuators use motors to turn lead screw, ball screw, or spur gear mechanisms to supply their output movement. These include mini-track, tube, and compact rotary types.
Compressed gas and oil are also used as power sources for small actuators. In general, these actuators differ little from their heavy-duty siblings barring their physical size and output capabilities. Both linear piston types and rotary vane or scotch yoke types are used to activate machine processes, open valves, and actuate ventilation and air conditioning equipment. Although not as large as heavy-duty types, these small actuators are generally far larger than electromagnetic types and typically produce far more output torque than any other type of comparable size.