Sheet prefeeder forming an overhead stock loop to the input of an incremental feeder for a cupping press

摘要

A prefeeder drive for a sheet of material positioned on the input side of a standard incremental type sheet feeder for a forming press and which has drive rolls that move a sheet of material through a lubrication bath and toward the press. The sheet is driven to form an upright or overhead loop prior to entry of the sheet into the main, incremental feeder. The drive comprises a pair of rolls which are driven in response to a feedback control system sensing the size of the overhead loop so that the loop size is maintained within a desired range to insure satisfactory feeding of the sheet material into the main feeder and thence into the press. The overhead or free standing loop substantially reduces the inertia of the material that the main feeder has to overcome when feeding an increment of sheet stock into the press, and thus makes the feeding of the material more reliable with less likelihood of misfeeds.