Abstract: An apparatus for corrugating material includes an upper shaft rotating about a first longitudinal axis and a lower shaft rotating about a second longitudinal axis. Either the upper shaft, the lower shaft, or both shafts are constructed of a flexible material. At least one upper corrugation roll is secured to the upper shaft, and at least one lower corrugation roll is secured to the lower shaft. The upper corrugation roll and the lower corrugation roll are interspersed relative to each other and spaced such that the material is fed between the upper and the lower corrugation roll to corrugate the material. Materials of varying rigidities may be passed between the upper and lower corrugation rolls such that lighter weight material is corrugated while heavier weight material deflects the flexible shaft(s) to reduce corrugation.

Abstract: An apparatus for straightening material includes a first guide surface and a second guide surface spaced from the first guide surface. As the material is passed along the first guide surface and along the second guide surface, the first guide surface induces a first curl in the material and the second guide surface induces a second curl in the material. The amount of the first curl may be in proportion to the rigidity of the material to be straightened, and the direction of the first curl may be opposite to that of the second curl.

Abstract: Lower, arced decurling guide (1) is pivoted on pin (3) and biased upward by spring (7). Upper stop (11) prevents the lower guide from moving closer to upper decurling roller (15). Paper (9) is guided between these upper and lower guides and the lower guide is moved outward in proportion to the rigidity of the paper being decurled. This automatic adjustment provides good decurling for all papers within a broad range of rigidity.