SHEET FEEDING DEVICE IN A SHEET PROCESSING LINE

摘要

A sheet feeding device for a sheet processing line, including sheet transporting and feeding means (14, 16) for transporting and feeding a sheet into the processing line, and delivery means for delivering the lowermost sheet in a stack to said transporting and feeding means, comprising rotary members (20, 22, 24) aligned in the sheet feeding direction (f), located upstream from the transporting and feeding means, and arranged in a suction housing (26). The rotary members project from the top (27) of the suction housing (26) and are capable at all times of engaging the lowermost sheet (12a) in the stack (12). Drive means for rotating the rotary members include a speed generator (40) with an output connected to the main line motor, and, for each of said rotary members, a mechanical clutch system and a braking system that may be selectively activated and deactivated depending on the position of the lowermost sheet in the stack relative to the rotary members. The speed generator generates a speed curve that includes an acceleration period, a constant-speed drive period and a deceleration period.