Drafting system unit and drafting system for a spinning machine

A drafting system for a spinning machine, having a first roller pair, which comprises a first top roller and a first bottom roller, and a second roller pair, which is formed by a second top roller and a second bottom roller, the first and second roller pair being spaced apart from one another in a fiber band transport direction (R) and being provided for drafting a fiber band transported from the first to the second roller pair, the respective axes of rotation of the first and second roller pair extending transversely to the fiber band transport direction (R),

• characterized in that
• an apron cage to which negative pressure can be applied is arranged between the first roller pair and the second roller pair for guiding an air-permeable apron in circulation jointly around the apron cage and an apron top roller, the apron top roller being formed by the first top roller of the first roller pair arranged upstream in the fiber band transport direction, or by a third top roller that is assigned to the apron cage and arranged on the same side as the first and second top roller in relation to the fiber band being transported, and the apron cage having at least one through-opening, to which negative pressure can be applied, for applying suction air to the fiber band running between the first roller pair and the second roller pair, through the air-permeable apron.

A method of using a fiber band compression device for compressing, within a drafting system, a drafted fiber band passing through an output top roller of a drafting system, the fiber band compression device having an apron cage, to which negative pressure can be applied, for guiding an air-permeable apron in circulation around an apron top roller and the apron cage, which has at least one through-opening to which negative pressure can be applied,

• characterized in that
• the fiber band compression device is arranged between a first roller pair and a second roller pair of the drafting system such that the apron cage guides the air-permeable apron jointly around the apron top roller and the apron cage, the apron top roller being formed by the first top roller of the first roller pair arranged upstream in the fiber transport direction, or by a third top roller that is assigned to the apron cage and arranged on the same side as the top rollers of the first and second roller pair in relation to the fiber band being transported, and the through-opening is arranged to apply suction air to the fiber band running between the spaced-apart roller pairs, through the air-permeable apron.