Device for pressing a stack of sheets against a roller drive of a papersheet separator

A device for pressing a stack of sheets against a roller drive of a paper sheet separator including a pressure plate pivotally journalled at one of its ends about a bearing shaft which defines a pivot axis, a single leaf spring arranged to apply a pressure force against said pressure plate at a location which establishes a lever arm extending from said pivot axis to said location, said pressure plate serving as a carrier of a stack of sheets, said carrier being capable of applying a pressure force to said stack, means for varying the pressure force of said carrier including a carriage means, said leaf spring being secured on said carriage means, said carriage means and said leaf springs being movable along a straight line path toward and away from said one end in a direction perpendicular to said pivot axis, said carriage means being movable along said straight line path to vary the length of said lever arm and the location on said pressure plate at which the pressure force is applied by said leaf spring, a carrier plate underlying said carrier, said carriage means being guided on said carrier plate, said carrier and said carrier plate being journalled on said bearing shaft, said bearing shaft having a section which has a round portion and a flat portion on its cross-sectional periphery and said carrier plate having a resilient member, said section of said bearing shaft and said resilient member providing a cooperating means operating to permit relatively easy motion of said carrier plate along said shaft when said shaft is turned so that said resilient member engages said flat portion and to inhibit such motion when said shaft is turned so that said resilient member engages said round portion.