Abstract: Integrated in the mixing head of a polyurethane apparatus for producing a mixture stream of chemically reactive plastic components, is a cutting arrangement by which natural fibers or fiber strands of soft-elastic and tough consistency can be drawn from a continuous strand and, after cutting into fiber pieces of given length, can be introduced into the mixture stream. The cutting arrangement includes an inner guide tube which receives a fiber strand, drawn from a continuous fiber strand by two feed rollers, and fed via the guide tube and an outer support tube to rotating knife elements. By subjecting the guide tube to a vacuum and applying a compressed gas stream to the end of the outer support tube, the soft-elastic fiber strand is held straight in a manner which is optimal for the cutting process. The cut fiber pieces are introduced together with the gas stream into the mixture stream of chemically reactive plastic components.

Abstract: Integrated in the mixing head of a polyurethane apparatus for producing a mixture stream of chemically reactive plastic components, is a cutting arrangement by which natural fibers or fiber strands of soft-elastic and tough consistency can be drawn from a continuous strand and, after cutting into fiber pieces of given length, can be introduced into the mixture stream. The cutting arrangement includes an inner guide tube which receives a fiber strand, drawn from a continuous fiber strand by two feed rollers, and fed via the guide tube and an outer support tube to rotating knife elements. By subjecting the guide tube to a vacuum and applying a compressed gas stream to the end of the outer support tube, the soft-elastic fiber strand is held straight in a manner which is optimal for the cutting process. The cut fiber pieces are introduced together with the gas stream into the mixture stream of chemically reactive plastic components.

Abstract: Integrated in the mixing head of a polyurethane apparatus for producing a mixture stream of chemically reactive plastic components, is a cutting arrangement by which natural fibers or fiber strands of soft-elastic and tough consistency can be drawn from a continuous strand and, after cutting into fiber pieces of given length, can be introduced into the mixture stream. The cutting arrangement includes an inner guide tube which receives a fiber strand, drawn from a continuous fiber strand by two feed rollers, and fed via the guide tube and an outer support tube to rotating knife elements. By subjecting the guide tube to a vacuum and applying a compressed gas stream to the end of the outer support tube, the soft-elastic fiber strand is held straight in a manner which is optimal for the cutting process. The cut fiber pieces are introduced together with the gas stream into the mixture stream of chemically reactive plastic components.