Gebruder Loepfe Ag

Loepfe Brothers Limited

Karl Lapp

Hansruedi Stutz

During the measurement of the length of filamentary materials, for instance a yarn, which is wound into a cross-wound package which is driven by a grooved drum, appreciable errors arise because there is not taken into account slippage. Therefore, with the present method during the winding operation the slip, which is governed by the relationship of the circumferential velocities of the grooved drum and the cross-wound package, is continuously measured in successive time intervals, and there is undertaken a correction of the yarn length determined without taking into account the slip. Thus, sensors continuously measure the rotational speeds of the cross-wound package and the grooved drum, and an angle measuring device determines the diameter of the cross-wound package, these measuring results then being inputted to an evaluation circuit. In the evaluation circuit there is computed the slip and such is incorporated into the length measurement.

Method for determining the length of filamentary materials, such as

A device for measuring the instantaneous value of the diameter or other transverse dimension of a traveling yarn comprises a linear array of photoelectric sensors and an electronic measuring device for digitally processing the electric signals furnished by the sensors in parallel form. A ground signal is taken with no yarn present and stored in the measuring device, and a measuring signal is taken with yarn present. The measuring device comprises logic circuitry for subtracting the stored ground signal from the measuring signal such as to eliminate the ground signal and to furnish a pure yarn signal representative of the yarn diameter.

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Zurich, Switzerland

Karl Lapp