Abstract: An electric switch wherein a fixed contact is engaged by a tiltable and reciprocable second contact under the action of an elastic washer or a coil spring. The second contact can be tilted by a projection, which extends from the housing, in cooperation with a flat abutment in the housing. When the projection is tilted, it causes the second contact to pivot relative to the abutment and to become disengaged from the fixed contact. The projection can be tilted by a bar or a tube which must be displaced by a person or object tending to penetrate into a danger zone, such as the nip of two cylinders in a printing machine or a machine tool. A third contact can be provided to be engaged by the second contact when the latter is disengaged from the fixed contact.