BigPatents India

A fiber bundle concentrating apparatus 11 is located downstream of a pair of final feed rollers 13 of a draft machine 12 and includes a feed part, which includes bottom nip rollers 20a, and suction pipes 29 located upstream of the nip points of the feed part along the moving direction of fiber bundles F. Each suction pipe 29 has a guiding surface 29b, which includes suction holes 29a. Perforated belts 18 are each wound about one of guide members 19, the corresponding bottom nip roller 20a, and the corresponding suction pipe 29 in a state where the perforated belt 18 slides against guiding surfaces 19a, 2 9b. Each suction pipe 2 9 includes a curved surface 2 9c, which extends along the circumferential surfaces of the bottom nip rollers 20a. Each bottom nip roller 20a includes grooves 33 the depths d of which are greater than or equal to 0.04 mm. The grooves 33 extend in a direction intersecting the circumferential direction of the bottom nip roller 20a corresponding to the width about which the corresponding perforated belt 18 is wound.