Method of controlling fiber-drawing apparatus

Abstract

A draw frame of a sliver-drafting apparatus has three cascaded roller pairs whose lower rollers are driven by respective motors at speeds determined by associated frequency dividers and/or multipliers in the output of a common oscillator of adjustable operating frequency. The slivers drafted by the roller pairs form, after doubling or plying, a fiber bundle traversing a thickness sensor whose output, integrated over predetermined time periods, is used by a microcomputer to ascertain optimum nip-line spacings and contact pressures reducing the thickness variations to a minimum. These parameters can be varied by horizontal slides supporting the roller pairs and spring-loaded blocks acting upon the shafts of the upper rollers; the positions of the slides and the pressures of the loading springs are adjustable by servomotors, under the control of the microcomputer, on the basis of a running-in program in which different combinations of values for the spacings and the pressures are successively set up and the combinations yielding the highest degree of uniformity are subsequently re-established.

Dependencies are inferred from the claim text.