Secret of travel switch

Travel switch.
Travel switch is also called limit switch, position switch or end switch. Convert the mechanical displacement signal into electrical signal with the same function as the control button.
The contact action relies on the mechanical displacement of the moving parts of the production equipment to collide with the travel switch, so that the contact action can complete the circuit connection or disconnection control.
The following is the roller travel switch:
The travel switch is composed of roller, lever, return spring, contact, microswitch, rotating shaft, impactor and cam.
In the figure above, after opening the cover plate, there are two pairs of contacts, one is open and the other is closed: NO represents normally open contact, and NC represents normally closed contact.
working principle:
When the block iron installed on the moving machine presses on the roller of the travel switch, the lever of the travel switch rotates with the rotating shaft and cam to push the impact block into it, disconnect the normally closed contact, close the normally closed contact, and switch the circuit; When the stopper on the roller moves, the return spring will restore the travel switch to the original position.
The travel switch above is single wheel and can reset automatically. The pressing angle of the travel switch roller is 90 ° and 180 °, which can be selected as required.
Precautions for travel switch:
1. Regularly clean the oil stain and dust of the travel switch, and clean the contacts;
Frequently check whether the travel switch acts flexibly and reliably and whether the screws are loose;
The roller is easy to wear and should be replaced according to the situation to avoid poor contact and failure to reach the purpose of stroke control and limitation.
The micro switch.
Micro switch is also a kind of travel switch. It is a main electrical appliance that converts mechanical signals into electrical signals. It is small in size, sensitive in action and small in travel.
As shown in the figure below.
Com is the common terminal, NO is the normally open point, and NC is the normally closed point.
Workflow:
When the external force extends out of the external transmission rod, the spring plate deforms, stores energy, and produces displacement. When the predetermined critical point is reached, the circuit is connected or cut off.
After the external force is eliminated, when the reverse displacement of the spring plate passes through another critical point, the contact will automatically reset under the action of the spring plate.
Note: Due to the small travel of the microswitch, attention must be paid during installation to prevent the microswitch from being crushed due to insufficient position. Frequently check whether the action of microswitch is sensitive and reliable.