Patent ID: 7392649

Claim:
A fiber opening device for an open-end spinning device comprising in combination: a cylindrical opening roller ( 2 ) having a circumferential fiber opening surface covered with projecting teeth ( 20 ) and operative to rotate about an axis (M) in a defined direction of rotation for separating a feed sliver ( 4 ) into individualized fibers for spinning into a yarn, a draw-in cylinder ( 7 ) rotatable adjacent the opening roller ( 2 ) about a parallel axis for delivering the feed sliver to the opening roller ( 2 ), and a feeding trough ( 8 ) operative in conjunction with the sliver draw-in cylinder ( 7 ) and the opening roller ( 2 ) for conveying the feed sliver ( 4 ), the feeding trough ( 8 ) comprising: a concavely shaped sliver gripping area ( 11 ) facing the sliver draw-in cylinder ( 7 ) for guiding the feed sliver therealong to the opening roller ( 2 ), a concavely shaped fiber support surface ( 13 ) facing the opening roller ( 2 ) for guiding therealong individualized fibers opened by the opening roller ( 2 ) toward a spinning location, and a transition area ( 14 ) between the support surface ( 13 ) and the gripping area ( 11 ), the feeding trough ( 8 ) being pivotable about a pivot axis ( 16 ) parallel to the axis (M) of rotation of the opening roller ( 2 ) for pivoting movement toward the draw-in cylinder ( 7 ) and the opening roller ( 2 ) into an operating position of the feeding trough ( 8 ) and for pivoting movement away from the draw-in cylinder ( 7 ) and the opening roller ( 2 ) in an angular direction of pivot rotation opposite the direction of rotation of the opening roller ( 2 ) into a non-operating position, the feeding trough ( 8 ) defining in its operating position a gap between the support surface ( 13 ) and the teeth ( 20 ) of the opening roller ( 2 ) and the feeding trough ( 8 ), the feeding trough ( 8 ) being configured and arranged such that, when in the operating position: the gap is maintained at a dimension A between 0.7 mm and 1.5 mm at a sliver combing-in point K along the circumference of the opening roller ( 2 ) and the gap constantly reduces to a dimension B less than or equal to 0.5 mm over a circumferential section W of the opening roller ( 2 ) extending from the combing-in point K in the direction of rotation of the opening roller ( 2 ) for at least 30° of the opening roller circumference, and the gap increases in the direction opposite to the rotation of the opening roller ( 2 ) away from the combing-in point K to a dimension C at the transition area ( 14 ) between the support surface ( 13 ) and the gripping area ( 11 ), the dimension C being sufficient substantially only that contact with the tips of the opening roller teeth ( 20 ) does not occur when pivoting the feeding trough ( 8 ) into its non-operating position.