Trim chute and method

A method of facilitating movement in a generally downwardly extending trim chute passageway of trim strip severed by a slitter from the margin of a travelling web, comprising:

• guiding the trim strip away from the slitter along a downward path in said passageway;
• along said path supplying low velocity air in downward direction and biasing the air generally toward and to flow along spaced wall surfaces defining said passageway and spaced from the respective opposite faces of the trim strip moving downward along said path;
• controlling the air in the form of cushioning and lubricating air layers along and between said faces of the trim strip and said wall surfaces and thereby effecting floatation of the strip and facilitating movement of the strip along said path and away from the slitter;
• and biasing the air in said layers generally toward and then to flow along said wall surfaces and thereby enhancing coanda effect in the downwardly moving air layers.

A trim chute assembly for receiving trim strip severed by a slitter from the margin of a travelling web, comprising:

• chute means defining a generally downwardly extending passageway for guiding the trim strip along a path downwardly away from the slitter;
• said chute means having opposed spaced passageway-defining wall surfaces between which the trim strip is adapted to pass freely downwardly in the passageway;
• means for supplying low velocity air downwardly and biasing the air generally toward and then to flow downwardly along said wall surfaces with enhanced coanda effect and providing cushioning, lubricating air layers which move substantially parallel to the direction of travel of the trim strip and at a controlled velocity about the same as the speed of travel of the travelling web so that as the air layers move downwardly along said path between said chute means wall surfaces and both of said opposite faces of the trim strip flotation of the strip downwardly in the passageway free from contact with said surfaces is effected and movement of the strip away from the slitter along said path is facilitated;
• said air supplying means comprising manifolds extending across and parallel to the path of movement of said trim strip and behind said wall surfaces;
• said manifolds having air delivery port means therealong directed generally downwardly;
• plate means coacting with said manifolds and defining distribution and air modulating chambers into which said port means discharge air from the manifolds;
• and orifice slots defined by said plates at said wall surfaces, and the air for said air layers issuing from said orifice slots.