Abstract: A direct drive cut-off has a pair of cylinders, each having a helical knife blade. The path of the knife blade around the cylinder defines a synchronous length. A corrugated board is passed in a board path direction between the cylinders at a production rate. The knife blades move in proximity to each other in the board direction to cut the continuous board into sheets. The knife blades enter the board path and engage the continuous board at a beginning of engagement position of a knife blade entering edge and depart the board path at an end of engagement position of a knife blade exiting edge. The sheets are accelerated downstream of the cylinders. The cylinders are controlled by a control unit for accelerating and decelerating the rotational speed of the cylinders so that the knife blades engage the continuous board at the specific length cutting the board into sheets. The control unit is responsive to the production rate, and the sheet length.

Abstract: A single facer has corrugating rolls of which the cross-sectional tip and root curves are elliptical (as broadly defined) to form a medium compression zone 38 beyond which, on each side of the tip center line, the root extends to define a clearance gap greater than the thickness of the medium; the root curve may (FIGS. 2 and 3) continue as an ellipse which also defines the flute flank, or alternatively the flute flank may be defined by a straight line 76 (FIG. 4) with a transition curve 58 between the straight line and the root curve 52. According to a different aspect of this invention, flank clearance is provided by the use of differently shaped flutes on the two corrugating rolls; for example (FIG. 5) the second roll 71 which carries the medium after corrugating may have straight flanks 76, and the other roll may have concave flanks 78.

Abstract: The web director is adapted to convey a web of paperboard from a first elevation to a second elevation. A web support is provided having a discrete convex surface and a discrete concave surface arranged so that the web may transfer from one surface to the other. The surfaces have a radius of curvature which facilitates passage of the web of paperboard without breaking.

Abstract: A dual cutoff machine system is provided for cutting two continuously moving rigid webs into sheets by way of first and second cutting devices at different elevations. The cutting devices are along first and second web paths which diverge in a downstream direction.

Abstract: A double facer platen is constructed so as to utilize a liquid heating medium which flows through a chamber containing a labyrinth defining a flow passage whose cross-sectional area decreases in the direction of flow from an inlet toward an outlet. The platen is adapted for use with liquids which have a temperature in excess of 400.degree. F. and a pump pressure of about 50 psi. The platen is supported by a beam having a temperature control means for compensating for any temperature difference between the upper and lower plates of the platen.

Abstract: A double facer platen is constructed so as to utilize a liquid heating medium which flows through a chamber containing a labyrinth defining a flow passage whose cross-sectional area decreases in the direction of flow from an inlet toward an outlet. The platen is adapted for use with liquids which have a temperature in excess of 400.degree. F. and a pump pressure of about 50 psi.