Abstract: An inductive measurement is carried out of the distance between a workpiece (3) and a working head (1), which bears an induction coil (8), through which an alternating current flows and which is part of a resonance circuit whose oscillation frequency is monitored for changes which occur as a consequence of changes in the distance between the workpiece (3) and working head (1). In this case, the working head (1) acts on the workpiece (3) with a material (2) having a dielectric constant greater than 1. The frequency of the alternating current is in the megahertz region or just therebelow. Last but not least, the induction coil is screened from external electric fields in order to avoid the influence of parasitic capacitances.

Abstract: The invention relates to a method and a device for measuring the distance between a sensor electrode and a workpiece. The sensor electrode forms, with the workpiece, a measuring capacitor through which an alternating current flows. A voltage present at the sensor electrode is tapped as a measuring voltage. In order to be able to remove the disturbing influence on the impedance of the measuring capacitor of a plasma forming between the sensor electrode and workpiece, the real part and the imaginary part from the measuring voltage are analyzed and used to determine the distance between the sensor electrode and the workpiece.

Abstract: The invention relates to a changing device for a lens holder of a connecting head for a laser machining tool. The lens holder includes a focusing optical system arranged therein. The changing device has at least one station including a holder for gripping and holding a lens holder and an actuator for engaging a fastener provided on the connecting head. The fastener fixes and/or releases the lens holder from the connecting head. Each station may further include structure for installing/removing a cutting nozzle, cleaning a cutting nozzle, and/or inspecting the optical system or cutting nozzle.

Abstract: A working head according to the invention for processing a workpiece by means of a laser beam includes a housing with an inlet opening and an outlet opening for the laser beam; a focusing optical system for focusing the laser beam at a point outside the housing at a spacing upstream of the outlet opening; and a measuring arrangement, surrounding the outlet opening, for measuring a spacing between it and the workpiece in the propagation direction of the laser beam, the laser beam traversing the focusing optical system and the outlet opening and measuring arrangement along beam axes which are at an angle to one another.

Abstract: A linear drive mechanism includes a cylindrical hollow housing within which a movable body is mounted for guided collinear movement by drive mechanism including a cable drum that is driven by a drive device having an output shaft, characterized by the provision of a slip clutch between the drive output shaft and the cable drum in order to avoid damage to the drive of the body in the event of a collision between the body and the workpiece in the direction of travel of the body. The drive mechanism may be used for the low-wear and play-free driving of, for example, the connecting head of a laser machining system for material processing.

Abstract: A method and apparatus for monitoring thermal processing of a workpiece using a sensor electrode which can be positioned relative to the workpiece and to which an alternating electric signal is applied in order to determine a measured capacitance (C.sub.meas) present between the sensor electrode and workpiece by evaluating a change in the alternating signal as a consequence of the measured capacitance (C.sub.meas). A measured capacitance frequency distribution is formed from a number of determined measured capacitances (C.sub.meas). The measured distribution is compared with a reference distribution. If a deviation is present between the two distributions, process parameters can be appropriately readjusted. It is preferable to use a laser beam for processing the workpiece.

Abstract: A sensor system is disclosed for the contactless measuring of the distance between a sensor body and an object. The sensor body contains an identification resistor, the resistance value of which can be interrogated by a control unit which is connected to the sensor body and which is located outside the sensor body. The interrogation makes it possible to determine whether the electrical connection between the control unit and the sensor body exists or is interrupted. If it is interrupted, this can be detected by the control unit in an unambiguous manner due to the missing connection to the identification resistor, and the control unit can generate an alarm signal in order to avoid faulty positioning of the sensor body relative to the object.

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 distance between a cutting torch and a work piece varies the oscillating frequency of the electrical control circuit. This frequency is converted by a discriminator into direct current signals, which are utilized to correct the deviations and hold the torch at a substantially constant distance from the work piece. As the torch moves away from the work piece, the bandwidth of the discriminator is widened, such as by damping or untuning a discriminator tuning circuit. A field-effect transistor is suitable for use as a damping resistor, and a capacitor-diode unit may be used to untune the tuning circuit. The control voltage is conveniently tapped from the output of an amplifier connected to the discriminator, and the control input may be provided to a variable resistor or capacitor. The control voltage for changing the frequency range is conveniently obtained from the analog signal component of the regulator output.