Safety switch for monitoring an access of an automation system comprising a stationary part and a movable part

#The present invention relates to a safety switch for monitoring an access of an automation system comprising a stationary part and a movable part.

#Conventional accesses which comprise the stationary part such as a machine frame, door framework, door frame, machine plate or holding bracket and the movable part such as doors, flaps or hoods, and which together ensure a safe access to the automation system have to be monitored by safety switches with respect to their state, open or closed.

#Such a monitoring is implemented, on the one hand, by electromechanical safety switches or, on the other hand, by contactless safety switches. There is the demand in this respect of a safe position monitoring of the movable part with respect to the stationary part of the access and, optionally, of detecting a holding closed of the two parts and to communicate it to a higher-ranking programmable logic controller PLC. The safety switches used for this purpose comprise a sensor part which is mounted in a fixed position to the stationary part of the access and a transmitter part which is mounted to the movable part of the access. When the access is closed, the transmitter part is located directly opposite the sensor part such that the sensor part can detect a signal of the transmitter part and can optionally communicate it as a release signal to the PLC so that the automation system can start.

#The invention will be explained in detail in the following with reference to embodiments and to the drawings. There are shown in the drawings:

#FIG. 1 a schematic representation of an access of an automation system; and

#FIG. 2 a large schematic view of a safety switch in accordance with the invention.

#An access Z to an automation system R is shown schematically in FIG. 1 which comprises a stationary part Z1 in the form of a wall or of a protective fence and a movable part Z2 in the form of a door. The access Z serves to prevent an access of a person to the automation system R during an operation or to bring the automation system R into a safe state with respect to the person. The stationary and movable parts Z1 and Z2 of the access Z each have a finitely wide frame in which a respective housing part 2 and 3 of a safety switch 1 in accordance with the invention is installed, wherein the safety switch 1 in accordance with the invention is provided to monitor a closed state or an open state of the access Z.

#In this respect, the safety switch 1 in accordance with the invention is able to detect whether the access Z is open, i.e. the movable part Z2 of the access Z is spaced apart from the stationary part Z1 of the access Z, or closed, i.e. the movable part Z2 of the access Z is arranged directly opposite the stationary part Z1 of the access Z.

#The safety switch 1 has first and second housing parts 2 and 3, wherein the first and second housing parts 2 and 3 are each provided with an elongate, preferably parallelepiped, shape. The first and second housing parts 2 and 3 are formed in a form-fitted manner with respect to one another.