Spring roller

In apparatus for transferring a sheet of material from a first roller to a second roller, both of said rollers having parallel longitudinal axes, said second roller being driven from a rotating drive shaft and said sheet unwinding from said first roller and winding onto said second roller, the improvement wherein said second roller is a spring roller for absorbing slack in said sheet, said spring roller comprising,

• a hollow, cylindrical roller body having a first end and a second end,
• a second shaft aligned with the longitudinal axis of said roller body and fixed to said first end of said roller body providing an axis around which said roller body can rotate,
• a sleeve fixed to said second end of said roller body, said sleeve having a first hole therethrough, said first hole extending along the longitudinal axis of said roller body, said drive shaft having a first end extending through said first hole in said sleeve into said roller body,
• a torsion spring having a first and a second end and being wound around the portion of said drive shaft extending into said roller body,
• means for connecting said first end of said spring to said first end of said drive shaft, and
• means for connecting said second end of said spring to said sleeve so that, during the transfer to said sheet from said first roller to said second roller, said spring is under tension and can absorb slack by allowing relative rotation between said spring roller and said drive shaft.