Suction braking apparatus

摘要

A suction braking apparatus for the braking and overlapping of sheets coming from a duplex crosscutter is provided which has a single suction chamber and can be quickly changed over to accommodate sheets of a different width. The suction chamber is provided with two groups of suction holes arranged in a row in the direction of travel of the sheets and has cover plates perforated in register therewith and each has a perforated control belt. Each group of suction holes has associated therewith a cover slide which is movable at a right angle to the direction of sheet travel with the two cover slides reciprocally covering a group of suction holes, starting from one of the two side edges and up to a junction extending in the direction of sheet travel.