Apparatus for forming urethane foam stock

Claim 1

Apparatus for forming polyurethane foam material having improved isotropicity and a substantially rectangular cross sectional configuration, comprising a four-sided molding tunnel having a transition section with fixedly mounted sidewall members outwardly and angularly positioned relative to the longitudinal axis of said tunnel for permitting substantially free and lateral expansion of said polyurethane foam within preselected limits functionally related to the foaming and gellation thereof, said transition section of said tunnel also having a top member upwardly and angularly positioned relative to said longitudinal axis of said tunnel for further permitting substantially free and vertical expansion of said polyurethane foam within preselected limits functionally related to the foaming and gellation thereof, said side and top members cooperating with the bottom members of said tunnel to provide said transition section thereof with a progressively outwardly flaring configuration with preselected internal cross sectional dimensions along said longitudinal axis functionally related to the characteristics of the polyurethane foam formulation along said axis of said tunnel, and conveyor means for transporting said polyurethane foam into and longitudinally through said transition section in functional cooperation with said foaming and gellation of said polyurethane foam and the internal dimensions and configuration of said transition section for achieving substantially uniform polyurethane foam cell configuration throughout said foam material.