Linear Actuator Types
Linear actuators create straight line motions and are, therefore, useful in machines that require linear motion. They are used in industrial machinery, peripherals of computers such as printers and drives of disks, in dampers and valves; in solar electronic consumer items, medical and health equipment, food preparation equipment, commercial satellites, and in agricultural, garden and lawn utilities. Gas or Liquid cylinders innately generate linear motion; while some equipment such as the ejection system used in DVD players must use linear motion.
There exist a wide variety of linear actuators which manufacturers typically offer to consumers. They include:
Ball Screw Actuators: These linear actuators merge a ball-screw and a DC motor gearbox into one unit. The actuator is usually complete, ready for installation and serve in various applications, from agricultural, medical, to industrial.
Worm Drive Actuators: Are actuators fitted acme screw for typical use in lifting chairs, dental and medical equipment, and fitness and mobility products. Consumers can choose them with or without power supply and self-control systems that are UL approved.
Acme Screw Actuators: Are a combination of acme screws and DC motor gearbox into one ready-to-install system. When individuals expect rugged and reliable performance, these linear actuators are preferred. They also serve in ventilation, solar tracking, gardens and lawns, ATV, and medical appliances.
VSJ Series: These linear actuators are more practical and applied in floor cleaning equipment, treadmills, practical industrial machines, and equipment for home healthcare. They consist of acme screws fitted in either DC or AC versions.
VI Series: These actuators proffer great versatility which makes them effective in operations that relate to lawns and gardens, medical equipment and in agricultural and ATV appliances. They exist in either acme or ball screw ranges and can be in DC or AC versions according to the task to perform.
Small Compact VMD series: These are greatly compact linear actuators. They are used in food preparation devices, automotive and office applications, and generally in light load tasks.
Apart from classifying linear actuators according to market availability, they can also be classified according to mechanisms of operation. In such classification, there are:
Mechanical Actuators: These can either be mechanical with digital micrometer readout or traveling screw in roller screw actuator. Mechanical actuators are used to convert rotary motion to linear motion through either of the following mechanisms:
Screw: The screw shaft follows in line with the rotating nut of the actuator. This is the principle of operation of screw jack, lead-screw and roller screw linear actuators.
Cam: They operate like wedges but with little travel.
Wheel and Axle: Linear actuators working according to this principle include the winch, chain drive, rigid chain, belt drive, winch, pinion and rack, hoist and rigid belt.
Liquid under Pressure Actuators (Hydraulic Actuators): Pressure is applied to a piston and conveyed through a liquid to a load piston, and then the external load is moved. Examples are equipment controlled by hydraulic pumps and the hydraulic car jack.
Compressed gas actuators: Are similar in principle to hydraulic actuators, except, uses gas instead of liquid.
Piezoelectric actuators: these actuators use voltage to make materials to expand and move external objects.
Electro-mechanical actuators: Instead of a handle or control knob of the mechanical actuator, an electric motor is used.
Small Compact Actuators: To reduce the bulk of linear actuators, specially designed motors in which an actuator and a motor are fitted into the smallest shape possible are used. Drive and screw are central in the motor or the motor is made very small.
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