Position switch
Position switch (also limit switch , limit switch or limit switch ) are sensors which detect when a moving object (such. As a workpiece or a machine part) a particular position has been reached. The generated signal can be forwarded electrically, hydraulically, pneumatically or mechanically. With sequential control systems in mechanical engineering that consist of several work steps, position switches recognize the end of a movement and thus initiate the next step in the process. Position switches are standardized according to EN 50041. They are also used as safety switches (e.g. door closed) to prevent damage to people and machines.
Examples for the use of position switches:
- The limit switch of the roller door of an underground car park recognizes when the roller door is fully raised, i.e. when it has reached its ' end position '. This signal causes that a) the electric drive is switched off and b) the traffic light in front of the gate changes from red to green.
- A workpiece is a blind hole - bore obtained, but a certain depth must not exceed. For this purpose, a position switch of the drilling machine is set so that when the specified depth is reached, the machine's feed is switched off and the return stroke is initiated.
- A limit switch in aviation is a limit switch that z. B. influences the mechanical process of running the chassis.
Common designs for limit switches are, for example, roller lever switches or non-contact devices such as light barriers and proximity switches or initiators .
literature
- F. Ebel, S. Nestel: Textbook proximity switches. Festo Didactic GmbH & Co. KG, Esslingen 2003, ISBN 3-8127-3045-6
