Abstract: A multi-piece valve disk of a sliding and/or seat valve, a ring seal with an elastic sealing ring with an external sealing zone is placed in a ring groove of the valve disk onto a dimensionally stable backup ring, and where an elastic restoring region effectively positioned between the backup ring and the external sealing zone is arranged in the backup ring, the restoring region being embodied in one piece with the sealing ring of its material adjacent to the external sealing zone of the sealing ring.

Abstract: A multi-piece valve disk of a sliding and/or seat valve, a ring seal with an elastic sealing ring with an external sealing zone is placed in a ring groove of the valve disk onto a dimensionally stable backup ring, and where an elastic restoring region effectively positioned between the backup ring and the external sealing zone is arranged in the backup ring, the restoring region being embodied in one piece with the sealing ring of its material adjacent to the external sealing zone of the sealing ring.

Abstract: The power-operated tool, preferably a screw driving implement, includes a switching clutch which transfers the torque from the drive shaft to the output shaft. Upon reaching the given reactive maximum torque, the switching mechanism is activated to turn off the drive. The clutch components are still engaged, so that one torque is transferred to the screw after the unit is turned off. This allows for unsupervised motion upon the output shaft. One should be able to interrupt the torque transfer to the output shaft completely and to return the switching clutch to its original position with certainty and ease. The switching mechanism maintains the valve body of the on-off valve in the open position, with the clutch component of the separating clutch separated by at least one buffer.