The term “linear actuator” has come to mean different things in different industries and applications. In a general sense, every linear actuator is a device which converts some type of rotary force and applies it to achieve an in-line or linear movement. This force could be coming from a hand crank or electric motor transferred through some type of screw for example. A good overview of general linear actuator principles can be found on Wikipedia at http://en.wikipedia.org/wiki/Linear_actuator .
Generally there are two types of linear actuators. The first type of “actuator”, often called a “rod-style actuator”, typically is round and has a screw in the middle of the moving element. This element or rod extends out the end of the cylinder and retracts back into the cylinder in a linear fashion. Along with being called actuators, often these are called by such other names as roller screw actuators, pneumatic or hydraulic cylinders, jack screws, etc. These types of actuators are typically only used in single axis applications.
The second type of “actuator” is built around either a square or rectangular structure of some sort, that encloses the drive or force transfer mechanism (screw, belt, etc.). This drive mechanism is attached to a carriage which is supported by some type of bearing system that guides the linear motion. PBC Linear specifically manufactures this type of electro-mechanical linear actuator with a range of drive options that can be powered either by a hand crank or motor. These types of systems can easily be configured for multiple X-Y-Z applications.
A third type worth mentioning has emerged on the market in recent years. It is the linear motor actuator, which rather than using a traditional rotary motor, incorporates a magnetic linear motor directly into the linear guidance system.
To see a multiple axis linear actuator system in action, watch the video at http://www.pbclinear.com/Videos/Linear-Actuator-Technology-from-PBC-Linear
