Abstract: A nozzle for a device for machining materials, can be rigidly connected at its end opposite the nozzle tip to a connector head of the device. The connection of the nozzle with the connector head is made by a connecting element (7; 17) made of a brittle material and comprising a break-off region (11; 20). If a collision between the nozzle tip and a workpiece to be machined takes place accidentally, then the connecting element breaks in the break-off region in order to prevent further, even greater damage to the connector head, nozzle or workpiece. The break-off region is crossed by an electrical conductor (14; 27) which breaks in the event of a collision, so that in this way an alarm signal for stopping the device can be generated.

Abstract: The invention relates to a tool head for machining a workpiece by means of a laser beam (10), which passes through an optical focusing system (2) which is disposed within the tool head and which is carried by a lens mounting (3) and which can be positioned only by displacing the lens mounting (3) relative to the tool head in the direction of the laser beam. The lens mounting (3) is displaced using automatic setting means (8, 9; 23).

Abstract: In a measuring device which serves to measure a geometrical variable with the use of a sensor which is fed an alternating measuring current of constant amplitude by a regulated, phase-dependent current source. An alternating supply voltage and an alternating measuring voltage tapped by the sensor via a feedback path of the current source is superimposed in a superimposition stage, which belongs to the current source and downstream of which a reference element for determining the alternating measuring current is connected, to form a total voltage present at the reference element. In order to match a characteristic representing the relationship between the alternating measuring voltage and the geometrical variable to a prescribed characteristic curve, at least one of the alternating voltages fed to the superimposition stage is varied. The variation can concern both the amplitude and the phase.