What Exactly Is A Limit Switch And How Does It Work?
The limit switch is an electromechanical device that serves as a sensor to detect and control the mechanical movement beyond the limit displacement. It is used to detect or sense the absence or presence, speed, travel limit, positioning, or the endpoint of an object in industrial environments.
A limit switch is equipped with a lever, knob, and plunger to make the detection. As soon as an object comes in contact with the limit switch, the sensor mechanically dislocates the actuator and makes or breaks an electrical connection.
What Are The Various Limit Switch Types?
In terms of limit switch types, there are four main categories. Let us dive deeper into each limit switch type:
Whisker – They are commonly used as a locating switch on an assembly line or conveyor. If an item is out of place and moves the whisker, the plunger is activated and the micro switch sends an alarm to the operator.
Roller – The roller switch is a handy Device – it has a wheel and lever function and is triggered when something moves past it.
Lever – They are used for heavy-duty E.O.T. cranes, wagon shunting devices, etc., to prevent over traveling or over traversing on power and control circuits up to 500 volts A.C. When the lever returns to zero, the contacts on the Limit Switch are reset automatically.
Plunger – They operate with little physical force. It comprises a spring and a set of contacts that convert mechanical energy applied to an actuator into an electrical output. They are extremely shock and vibration resistant and are designed to permit both vertical and angular actuation. These are typically used in drivetrains and conveyor systems, industrial equipment, marine applications, military & specialized commercial vehicles as well as transmissions.
Where Can Limit Switches Be Installed?
Door limit switches are used to prevent automatic garage door openers from crashing into the lifting mechanisms when a motor lifts the door. As the door closes, the door limit switch deactivates the engine to prevent it from being slammed into the ground.
Microwave doors use them to verify that the door is closed before any operation is allowed. A refrigerator door also uses a limit switch to turn on and off the light inside.
Limit switches with button actuators are used in dump trucks to detect when pallets are fully lowered. The switch closes when the button is pressed, signaling to the driver (via a light or alarm) that it is safe to drive.
Limit switches are also employed in assembly lines to detect when a predetermined number of additional components have been added to the product and trigger the actuator to move the equipment away, which shifts the product to the next station.
They also find their presence in construction machinery and equipment such as lift trucks, conveyor belts, cranes, hoists, to detect misalignment, eventually preventing mishaps.
Final Words
That’s all there is to the general meaning, applications, and limit switch types. I hope that helped.
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