The main application of limit switch is to change the displacements of the machine into electric signal, thus change the operation condition of the electric actuators
. Hence, the movement of equipment will be controlled and the machine program will be under control as well. There are still some limit switch facts to be introduced and the operation principle to be told.
In the first place, one of limit switch facts is about its classification. There are three types of limit switch: direct-acting kind, roller kind and micro-action kind. The working principle of direct-acting limit switch is the same as that of button switch. However, the switching speed of the contacts depends on the speed of machinery. As a result, this type of limit switch is not available under the circumstance that the speed is lower than 0.4 m/min. This is the limit switch fact about direction-acting kind. The next one is roller limit switch. When the block on the controlled machine hits the lance of the roller, the lance turns to the right side, driving the cam to rotate and pushing the putter. At this time, the contacts of micro switch start to work rapidly. When the moving mechanical components returns, each part of the operation section resets under the pushing of returning spring. That’s how the roller limit switch works. Another limit switch fact about roller kind is its classification. Roller limit switches can be divided to two type, one is single-wheel roller with automatic reset function and the other is dual-wheel roller with non-automatic reset function. The later type of roller limit switch has two stable positions which have “memory” effect. In certain occasion, the lines can be simplified. The micro-action limit switch is not commonly used as the former two types. The most popular series is LXW-11 series production.
The next limit switch fact I’d like to share is about its material. Different from the pneumatic actuators
, the material of contacts is aurum which is resistant to corrosion. Meanwhile, its relatively soft surface is quite suitable. What’s more, alloys are commonly used as material of limit switch such as Au-Ag alloy. At the same time, plastic materials are widely used. PBT, PPS and PBTP are the materials of most limit switches.
Lastly, the limit switch facts that I am going to share are about their terminology. The first one is ranting which means the volume of its features and its performance such as rated current and rated voltage. The second one is existent point of contacts which means that the open or close of mechanical contacts is used to realize the function of limit switch. The last one is contact form which means various approaches where electrical energy gets into or out of the circuit according to their specific features.
Featured Products: rotary pneumatic actuator | bettis pneumatic actuator