A method and apparatus for preparing container board having a corrugated medium and at least one liner formed thereon for folding which comprises a tool for displacing in a non-destructive manner the corrugated medium and the liner in a portion of the board to form a curved indentation therein. The device includes a separate tool for forming a line of weakness in the liner along the curved indentation portion of the board. This arrangement increases the dimensional accuracy of the container board by substantially eliminating the occurrences of "false" score lines or rolling scores.
It is desired to provide a creasing device of which the distances between rollers of a plurality of creasing units are individually adjustable.A plurality of creasing units 40 each comprising a female creasing roll 41 and a male creasing roll 42 provided thereunder are provided so as to be positionable in a direction perpendicular to the feed direction of a corrugated sheet S0. As many roller arms 43 as the creasing units 40 are provided so as to be pivotable about a common first drive shaft 31. Each roller arm 43 rotatably supports one of the male creasing rolls 42. By pivoting each roller arm 43 with a pivoting means 45, the male creasing roll 42 is moved relative to the corresponding female creasing roll 41, thereby adjusting the distance between the rolls.
A drum for a creasing device, a resilient creasing ring and method are provided. The drum includes first and second drum parts that cooperate with one another to define a circumferential channel of the drum a base and two side wall for receiving a resilient creasing ring. At least one of the side walls includes recess for receiving a portion of the resilient creasing ring such that the resilient creasing ring cannot be removed radially from the channel. The creasing ring may be continuous or a split ring.
