A linear actuator develops force and motion from an energy source. As evident by its name, the force and motion from this energy source is created in a linear manner by the linear actuator. This is contrast to the force and device developed by an electric actuator. The electric actuator develops force and motion rotationally. There are several kinds of linear actuators and linear motion can be achieved by many devices. Below is a list of types of linear actuators. Basically, actuators produce converts various forms of energy into mechanical energy.

Hydraulic linear actuator: Hydraulic cylinders, better known as hydraulic actuators have a hollow cylinder with a piston inserted inside it. As its name suggests, the hydraulic linear actuator is built on hydraulic principle. The controlled precise linear displacement of the piston is achieved with the alternate pressurization and depressurization. This is turn creates a controlled and precise linear displacement in the entity that is connected to the piston. They normally use a hydraulic fluid and a cylinder to create motive force. An incompressible fluid is used to apply a force at one point, which is then transmitted to another point. Hydraulic linear actuators are a low maintenance device. Also, they work well for longer periods of times even in bad environmental conditions. Hydraulic actuators are quite an important part in hydraulic table lifts, used to move around heavy workpieces and hydraulic cab lifts, which are generally used in tow trucks and fire engines.

Electro Mechanical Actuators: Electro mechanical linear actuators are quite similar to mechanical actuators. The only major difference between an electro mechanical and a mechanical linear actuator is that the control knob is an electric motor. The rotary motion is then converted into linear displacement of the actuator.

In a linear actuator, a drive screw is rotated by a motor. This is done with the help of a synchronous timing belt drive or a direct drive or worm gear drive. This turning of the screw helps in pushing the drive nut along the screw. This drive nut in turn pushes the drive nut along the screw, and pushes the rod out. The rotation of the screw in the opposite direction will retract the rod.

The basic concept of linear actuator is to move an object in a straight line. Therefore, you would have to consider the purpose of the project before deciding on a linear actuator. The main aspects that you would have to keep in mind are the stroke length, the speed and the load rating of the actuator, before deciding on the type of actuator that you would be using.

There is a lot of information available about linear actuators all around. The Internet is the best place to get information about linear actuators. You can sign up on any forums or groups to find more information about the various types of linear actuators. Of course, while using linear actuators you will have to keep several things in mind, like safety concerns, environmental hazards and space constraints.