Abstract: Disclosed is an improved safety guard for use with sheet feeding mechanisms which is disposed between the feeding mechanism and the exposed feed roll nip of a mechanism for the processing of the sheet material. The safety guard includes a non-rigid, non-elastic member which prevents an attendant from inadvertently placing his appendages in the exposed nip of feed rolls while not interfering with the passage of the sheet material from the feed mechanism to the feed rolls of the processor. The safety guard adjusts automatically and instantaneously as the width of the sheet material changes to shield the variation in exposure.

Abstract: An improved corrugator roll for use in an apparatus for making corrugated paperboard wherein the flute tip and a portion flank of the roll base metal are selectively hardened to a predetermined depth by an electro magnetic process. The valleys of the flutes and the remainder of the flank are maintained at the same hardness as the base material.

Abstract: An improved web guide structure of the self-adjusting type for a corrugated web single-facer machine including a plurality of laterally spaced guides for continuously and yieldably urging a corrugated medium web against a lower corrugator roller, a support rigidly mounted to the single-facer for pivotally supporting the guides, and a gravity-actuated and adjustable biasing means for urging the guides against the corrugated web at preselected pressures. The guides preferably include a trailing guide portion that remains in engagement with an adhesive applicator roll when the roll is moved out of engagement with the corrugated web to maintain alignment of the guides with the roll. Springs may also be used in conjunction with the support to apply greater or lesser pressure to all of the guides simultaneously.