Sheet material cutting apparatus including a vacuum holddown system having a roller mechanism for handling air-impermeable sheets

Claim 1

A sheet material cutting apparatus comprising a table having a surface for supporting a layup of sheets of material to be cut, a main carriage connected with said table for movement longitudinally of said supporting surface, a cutter connected with said main carriage for movement therewith longitudinally of said supporting surface and operable to cut said layup of sheet material supported by said supporting surface at a cutting zone which moves with said cutter relative to said layup, two rotatable rollers carried by said main carriage for movement therewith longitudinally of said supporting surface, said two rollers extending transversely of said supporting surface and being located on opposite sides of said cutting zone, two cover sheets of air-impervious sheet material each associated with a respective one of said rollers, said two cover sheets including portions wound respectively onto said two rollers in opposite directions and other portions extending in opposite directions from said cutting zone into overlying relationship with said layup with the portion of said layup located below the gap between said two rollers being uncovered by said cover sheets, means for producing a sub-atmospheric pressure adjacent the undersurfaces of said two cover sheets so that atmospheric pressure pushes them toward said supporting surface to compress said layup between said cover sheets and said supporting surface, and means for biasing each of said rollers about its axis of rotation in the direction to wind its associated sheet thereon so that as said main carriage moves longitudinally of said supporting surface one of said sheets is wound onto its roller by the action of its biasing means and the other of said two sheets is unwound from its roller against the action of its biasing means.