Apparatus for stiffening flexible sheets during travel

975,049. Delivering sheets. S. D. WARREN CO. Oct. 4, 1963 [Nov. 5, 1962], No. 39225/63. Heading B6H. Apparatus for temporarily stiffening sheets travelling along a set path comprises a support structure forming part of the path, the structure including a number of laterally spaced support surfaces extending along the path, and means for applying differential air pressure across the sheets when travelling over the structure, the means being such that the pressure on the side of the sheet facing the structure is less than that on the other side whereby parts of the sheet are drawn downwardly between adjacent support surfaces to corrugate the sheet and thus to stiffen it. Sheets are delivered from a cutting machine by a high-speed conveyer 13 and deposited in overlapping fashion on a low-speed conveyer 14. Each conveyer comprises a plurality of spaced endless tapes. The middle three tapes of conveyer 13 are parallel and the outer tapes converge towards the forward end of the conveyer. A suction box 26, arranged beneath the conveyer 13, includes a number of laterally spaced supports 27 for the tapes. Between the supports are positioned a number of baffles 28. The latter extend beyond the box as at 29 into recesses between collars 21 and 22 supporting the tapes. Slots 30 are provided between the baffles and supports by means of which suction is applied to the undersides of the sheets passing thereover. Thus the sheets are corrugated transversely to stiffen the same. A suction hose 31 is connected to one end of the box beneath the level of a horizontal baffle-plate 34. A series of graduated size holes is provided in the plate 34 to distribute the air flow through the slots 30. A second high-speed conveyer 11 and suction box 33 may be provided between the cutting machine and high-speed conveyer 13.