Abstract: A safety access to a room in particular a class room with a safety lock, an entry from outside and an exit to the room, comprising a first door in the exit and a locking door which renders the locking chamber lockable.

Abstract: A device for controlling the accuracy of the orbit along which a work spindle of an NC machine is moved during the manufacture of high-precision circular bores, inner and outer surfaces as well as radii essentially consists of a control unit (1), a clamping element (3) as well as an intermediate piece (2). The clamping element is connected to the work spindle of the machine tool and the control unit is placed on the work table of the machine tool, at the location at which the workpiece is held during the machining. The intermediate piece (2) is formed by a transducer (24) or comprises a transducer. If deviations from the nominal radius occur, the transducer transmits a signal to an amplifier, said signal being amplified and subsequently displayed and/or recorded. A shaft encoder (61) allows the precise determination and, if so required, registration of the respective measuring position. A special routing of the measuring cable and an internal transmission by means of a slip ring (66) and sensors (67), e.g.

Abstract: Switching equipment for numerically controlled machine tools is provided with at least one controllable switch for initiating a measuring process and a switch control which closes the switch when a supply voltage appears on a connecting wire, for example on a power supply connecting wire of an electric pump for cooling water. Therefore it is possible to measure automatically without any additional program-steps of the central processing unit.