Abstract: In a method for measuring a reference position of a tool relative to a workpiece, the tool is fastened to a first holder of a machine tool. The workpiece is to be manufactured using the tool and is fastened to a second holder of the machine tool. The tool provides a distinguishing mark on the workpiece in a predetermined reference position of the first holder relative to the second holder. Subsequently, the distinguishing mark is detected by a sensor. Therefore, the reference position of the tool relative to the workpiece is determined from a position of the first holder relative to the second holder. The tool and the sensor are fastened in fixed, permanent positions relative to one another and relative to the first holder. The accuracy of measurement of the position of the tool depends exclusively on the accuracy of positioning of the first holder relative to the second holder.

Abstract: A connector for light waveguides comprising a housing and at least one clamping member provided in the housing. The clamping member comprises a base having a V-shaped guide groove extending in the longitudinal direction of the housing. The guide groove receives a light waveguide plug. A pressure element is provided opposite the guide groove. The pressure element consists of a clamping bridge and pressure members acting thereon. The height of the pressure members is smaller than the distance between the engaging surface of the clamping bridge and the wall of the housing extending opposite the engaging surface. Screw caps are provided to be screwed laterally on the housing and to act on the pressure members via a pressure piece. The pressure members consist of individual balls which have the same diameter and which are provided in at least one row, one behind the other, in the direction of the longitudinal axis of the housing.

Abstract: A connector, for coupling pairs of (monomode) optical fibers, comprising a central connection portion, with a V-groove, and two holders. A cylindrical envelope of an optical fiber is arranged in each holder to be resilient in the longitudinal direction. A pin 4 is secured parallel to each envelope. The envelope is retained in the V-groove by a hold-down spring. When the envelope and the pin are inserted into the central connection portion, the envelope is clamped by a clamping spring which is actuated by the pin after the envelope has reached its ultimate position, e.g. against an abutment pin.

Abstract: The invention relates to a method of and a device for providing an outer surface of an envelope which is concentric to a light-conductive core, around a monomode optical fiber. According to the invention, the eccentricity of the fiber and the envelope may be for example, 0.1 .mu.m for a core diameter of 3 .mu.m. This accuracy is acieved by splitting a light beam, emerging from the end of a fiber which is clamped in an envelope, into two subbeams by means of rotating optical means, each of the beams producing a circular image. By a suitable choice and adjustment of the optical means, the two light beams will form oppositely moving images when the fiber end is displaced with respect to the axis of rotation and observation. When the images are concentric, the fiber end is situated on the axis of rotation. Machining of the envelope by the use of a tool which rotates around the axis of rotation results in an envelope which is concentric to the light-conductive core of the fiber.