Contactless system for measuring centricity and diameter

#The present application is a U.S. National Stage of International Application No. PCT/EP03/02117, filed Mar. 1, 2003, designating the United States and claiming priority of German Application No. 102 15 432.5 filed Apr. 8, 2002 and German Application No. 102 19 848.9 filed May 3, 2002.

#The invention relates to a contactless system for measuring centricity and diameter, said system comprising i) an optical measuring device for determining the external diameter and position of a harness in an optical measuring plane, arranged perpendicular and transverse to the central axis Z of a measuring device, wherein the harness comprises a conductor and a jacket for insulating said conductor and is pulled in the direction of the central axis Z through the measuring device; ii) an inductive measuring coil arrangement for determining the position of the conductor in an inductive measuring plane, which is also arranged perpendicular and transverse to the central axis Z of the measuring device; and iii) means which correlate the position of the harness determined with the optical measuring device and the position of the conductor determined with the inductive measuring coil arrangement and which calculate from this correlation the centricity of the conductor inside the jacket. The invention also relates to a corresponding method.

#The harness in particular is a cable. When producing such harnesses and in particular cables, the jacket or coating is normally affixed to the conductor by means of extrusion, wherein the jacket can consist of one layer or can be composed of several layers that concentrically surround the conductor.

#The invention is explained in further detail in the following with the aid of the enclosed drawings, which show preferred embodiments that illustrate the invention diagrammatically and not true to scale, wherein the drawings show in:

#FIG. 1 A system overview of the device according to the invention;

#FIG. 2 The structural principle for a measuring device in the form of a measurement yoke according to a first embodiment of the invention;

#With the device according to the invention, e.g. as shown in FIG. 1, a cable 3 is guided through a measuring device 2 in the form of a measurement yoke. As can be seen in FIG. 3, this cable 3 has a centered conductor 4 that is surrounded by a jacket 5 of an insulating material. A cable 3 of this type is normally produced by extruding it. The device according to the invention or the measurement yoke 2 can be integrated into the currently running production line for this cable 3 and can be positioned downstream of the extrusion nozzle, either in front of the normally used cooling bath or even behind it. A current 9 is induced in this cable 3 with the aid of an oscillator 6, e.g. a 160 kHz oscillator, and an amplifier 7 (e.g. 60 watt), as well as an inductor 8.

#The measurement yoke 2, shown in further detail in FIG. 2, comprises a housing 10 and has an approximately disk-shaped or plate-shaped design. The center of this housing contains a central opening 12 through which the cable 3 can be pulled, wherein the cable is inserted through a slot 11 into this opening 12. The central axis Z extends perpendicular to the housing 10 and thus also perpendicular to the paper plane in FIG. 2, wherein the housing 10 is located approximately in the paper plane. The central opening 12 has an essentially circular design.

#The housing 10 extends by several centimeters in the direction of the central axis Z. The housing 10 contains the optical measuring device and the inductive measuring coil arrangement.