Selectively tearable stock material for a dunnage conversion machine
View Patent ↗A stock material ( 16 ) for use with a dunnage conversion machine ( 14 ) includes at least one ply of sheet material having spaced along the length thereof a plurality of transverse rows ( 22 ) of weakened areas ( 24 ). The weakened areas ( 24 ), which can be formed by perforations, for example, have a reduced strength relative to adjacent portions of the sheet material. Each row ( 22 ) of weakened areas ( 24 ) has at least one parameter that varies along the row ( 22 ). The strength of the stock material at the row ( 22 ), in response to a force applied across the row ( 22 ), varies across the stock material ( 16 ).
1. A stock material for a dunnage conversion machine comprises at least one ply of sheet material having a plurality of transversely-extending, longitudinally spaced-apart rows of weakened areas, where the weakened areas have a reduced strength relative to adjacent portions of the sheet material, and each row of weakened areas has at least one parameter that varies along the row, whereby the strength of the stock material at the row, in response to a force applied across the row, varies across the stock material, wherein each ply has lateral edge portions that are substantially free of weakened areas, and at least one ply includes paper; wherein the weakened areas include one or more perforations and at least one edge of the stock material is free of perforations for approximately 0.6 cm to 3.8 cm (approximately ¼ inch to 1½ inches) along each row of weakened areas.
2. A stock material as set forth in claim 1 , wherein the at least one parameter that varies includes at least one of the manner in which each weakened area is weakened, the degree to which each weakened area is weakened, the spacing of the weakened areas within the row, the size of each weakened area within the row, the shape of each weakened area within the row or the orientation of each weakened area within the row.
3. A stock material as set forth in claim 1 , wherein the spacing of at least three perforations is uniform.
4. A stock material as set forth in claim 1 , wherein the perforations in at least two different rows have different parameters.
5. A stock material as set forth in claim 1 , wherein the stock material includes a material selected from a group consisting of kraft paper, plastic, printed paper, bleached paper, newsprint, recycled paper and combinations thereof.
6. A stock material as set forth in claim 1 , wherein the stock material includes multiple plies, and each ply has lateral edge portions that are substantially free of weakened areas.
7. A stock material as set forth in claim 6 , wherein each ply is perforated only in a central portion of the ply between the lateral edge portions.
8. A stock material as set forth in claim 1 , wherein the at least one ply includes a series of alternating folds that form a sequence of rectangular pages that are piled accordion-style one on top of another to form a stack of fan-folded stock material.
9. A stock material as set forth in claim 8 , wherein the fold lines coincide with the tear lines.
10. A stock material as set forth in claim 1 , wherein at least one row is substantially perpendicular to a longitudinal dimension of the stock material.