Patent ID: 6640154
Filing Date: 2003-10-28
Classification: D01H

Abstract:
A device for determining and optimizing a pre-draft value on a draw unit for slivers, the draw unit having a feed roll pair, a center roll pair and a delivery roll pair, a pre-draft zone between the feed roll pair and the center roll pair, and a main draft zone between the center roll pair and the delivery roll pair, the device comprising:a center roll drive motor for driving a lower roll of the center roll pair; a sensor for measuring values of a variable indicative of draft forces at the center roll drive motor; and means for controlling the drive motor in accordance with a function defining a relationship between the measured value and the pre-draft value, the function indicating an optimum region having at least one of an increase end point and an increase end region, the optimum region providing a parameter that is usable for optimizing the pre-draft value for the draw unit, wherein a speed of the center roll drive motor is controlled to adjust a ratio of circumferential speeds of the center roll pair to the feed roll pair in order to change the pre-draft value.