Patent ID: 6570272
Filing Date: 2003-05-27
Classification: H01H

Abstract:
A safety switching device for connecting and safely disconnecting an electrical load in response to an external switching signal, said switching device comprising:a relay having at least a first operating contact, a first auxiliary contact, and a first nominal switching capacity, said first operating contact and said first auxiliary contact each having a first and a second switch position, and said contacts being linked to one another such that the switch position of said first auxiliary contact is necessarily coupled to the switch position of said first operating contact, thereby allowing to reliably determine the switch position of said first operating contact from the switch position of said first auxiliary contact, a contactor having at least a second operating contact, a second auxiliary contact, and a second nominal switching capacity which is higher than said first nominal switching capacity, said second operating contact and said second auxiliary contact each having a third and a fourth switch position, and said second operating contact and second auxiliary contact being linked to one another such that the switch position of said second auxiliary contact is necessarily coupled to the switch position of said second operating contact, thereby allowing to reliably determine the switch position of said second operating contact from the switch position of said second auxiliary contact, at least a first input terminal, a second input terminal, and an output terminal, wherein said first and second operating contacts are arranged in series with one another between said first input terminal and said output terminal, and wherein said second input terminal is adapted to receive said switching signal, and a timer unit connected to said second input terminal, said timer unit being adapted to process said switching signal such that, when connecting the load, the switching signal acts on the first operating contact earlier than on the second operating contact, and, when disconnecting the load, the switching signal acts on the first operating contact later than on the second operating contact.