Dunnage conversion machine for producing a dunnage pad having slit-sheet material therein

Patent metadata

Field	Value
Publication number	US-12115753-B2
Application number	US-202117905986-A
Country	US
Kind code	B2
Filing date	Mar 9, 2021
Priority date	Mar 9, 2020
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

Abstract

A dunnage conversion machine includes (i) a pair of gripping rollers configured to rotate at a first rotational speed to advance a slit-sheet material in a downstream direction; (ii) a pair of expansion rollers configured to rotate at a second rotational speed, faster than the first rotational speed, creating a stretching force on the slit-sheet material and further advancing the slit-sheet material, causing expansion of the slit-sheet material to a fully expanded state; and (iii) a pair of relaxation rollers configured to rotate at a third rotational speed, slower than the second rotational speed, reducing the stretching force and further advancing the slit-sheet material, allowing the slit-sheet material to relax to a partially expanded state. The pair of relaxation rollers (iii) also are configured to capture the slit-sheet material in the partially expanded state between a top cover sheet and a bottom cover sheet to form a dunnage pad.

First claim

We claim:

1. A dunnage conversion machine for producing a dunnage pad from a slit-sheet material having a plurality of rows of slits extending across a width dimension of the sheet with adjacent rows laterally offset, the dunnage conversion machine comprising:
means for advancing the slit-sheet material in an unexpanded state from a supply in a downstream direction transverse the width dimension at a first rate;
means for expanding the slit-sheet material downstream of the advancing means, the expanding means creating tension in the slit-sheet material transverse the width dimension downstream of the advancing means to cause the slits to open to a fully-expanded state; and
means for reducing the tension in the slit-sheet material downstream of the expanding means to cause the slits to relax from the fully-expanded state to a partially-expanded state, and
for connecting the slit-sheet material in the partially-expanded state to at least one cover sheet to form a dunnage pad.

2. A dunnage conversion machine as set forth in claim 1 , further comprising means for separating a discrete length of the dunnage pad for use.

3. A dunnage conversion machine as set forth in claim 1 , wherein the advancing means includes a pair of opposed gripping rollers configured to grip the slit-sheet material therebetween in an unexpanded state and to rotate at a first rotational speed to advance the slit sheet material in a downstream direction.

4. A dunnage conversion machine as set forth in claim 3 , wherein the expanding means includes a pair of expansion rollers configured to engage the slit-sheet material and to rotate at a second rotational speed, the second rotational speed being faster than the first rotational speed to create a stretching force on the slit-sheet material in a region between the gripping rollers and the expansion rollers and to further advance the slit-sheet material in the downstream direction, wherein the stretching force causes expansion of the slit-sheet material to a fully expanded state.

5. A dunnage conversion machine as set forth in claim 4 , wherein the expanding means and the reducing means are provided by a pair of relaxation rollers downstream of the pair of expansion rollers, the pair of relaxation rollers being configured to engage the slit-sheet material and to rotate at a third rotational speed, the third rotational speed being slower than the second rotational speed to reduce the stretching force on the slit-sheet material in a region between the expansion rollers and the relaxation rollers and to further advance the slit-sheet material in the downstream direction, wherein the reduction of stretching force causes relaxation of the slit-sheet material to a partially expanded state, and wherein the pair of relaxation rollers are configured to capture the slit-sheet material in the partially expanded state against a cover sheet to form the dunnage pad.

6. A dunnage conversion machine for producing a dunnage pad from a slit-sheet material having a plurality of rows of slits extending across a width dimension of the sheet with adjacent rows laterally offset, the dunnage conversion machine comprising:
a pair of gripping rollers being configured to grip a slit-sheet material therebetween in an unexpanded state and to rotate at a first rotational speed to advance the slit-sheet material in a downstream direction transverse the width dimension;
a pair of expansion rollers downstream of the pair of gripping rollers, the pair of expansion rollers being configured to engage the slit-sheet material and to rotate at a second rotational speed, the second rotational speed being faster than the first rotational speed to create a stretching force on the slit-sheet material transverse the width dimension in a region between the gripping rollers and the expansion rollers and to further advance the slit-sheet material in the downstream direction, wherein the stretching force causes expansion of the slit-sheet material to a fully expanded state; and
a pair of relaxation rollers downstream of the pair of expansion rollers, the pair of relaxation rollers being configured to engage the slit-sheet material and to rotate at a third rotational speed, the third rotational speed being slower than the second rotational speed to reduce the stretching force on the slit-sheet material in a region between the expansion rollers and the relaxation rollers and to further advance the slit-sheet material in the downstream direction, wherein the reduction of stretching force causes relaxation of the slit-sheet material to a partially expanded state, and wherein the pair of relaxation rollers are configured to capture the slit-sheet material in the partially expanded state against a cover sheet to form the dunnage pad.

7. The dunnage conversion machine according to claim 6 , further comprising:
a housing that supports the pair of gripping rollers, the pair of expansion rollers, and the pair of relaxation rollers;
an opening at an upstream end of the housing configured to receive the slit-sheet material in the unexpanded state from a supply of slit-sheet material; and
a discharge outlet at a downstream end of the housing for delivering the formed dunnage pad.

8. The dunnage conversion machine according to claim 6 , wherein the pair of relaxation rollers are configured to receive a top cover sheet from a supply of top cover sheet material and a bottom cover sheet from a supply of bottom cover sheet material therebetween and on opposing sides of the partially-expanded slit-sheet material.

9. The dunnage conversion machine according to claim 8 , wherein the pair of relaxation rollers are configured to capture the slit-sheet material in the partially expanded state between the top cover sheet and the bottom cover sheet by fixing at least a portion of a periphery of the top cover sheet and at least a portion of a periphery of the bottom cover sheet to each other, with at least a portion of a periphery of the slit-sheet material in the partially expanded state being fixed therebetween.

10. The dunnage conversion machine according to claim 9 , wherein the at least a portion of the periphery of the top cover sheet and the at least a portion of the periphery of the bottom cover sheet each have a cohesive coating thereon and the relaxation rollers are configured to adhere the at least a portion of the periphery of the top cover sheet and the at least a portion of the periphery of the bottom cover sheet to each other by pressing the cohesive-coated portions together.

11. The dunnage conversion machine according to claim 6 , wherein the pair of relaxation rollers are configured to receive a separator sheet from a supply of separator sheet therebetween and between the slit-sheet material and at least one cover sheet.

12. The dunnage conversion machine according to claim 11 , wherein the separator sheet has a width that is less than each of a width of the cover sheet and a width of the slit-sheet material in the partially expanded state.

13. The dunnage conversion machine according to claim 6 , further comprising a cutting device mounted in the dunnage conversion machine downstream of the relaxation rollers, the cutting device being configured to cut the dunnage pad after a desired length has been formed.

14. A system for producing a dunnage pad from a slit-sheet material having a plurality of rows of slits extending across a width dimension of the sheet with adjacent rows laterally offset, the system comprising:
the dunnage conversion machine according to claim 6 ;
a controller configured to maintain the first rotational speed, the second rotational speed, and the third rotationa

Assignees

• Ranpak Corp

Inventors

• Cheich Robert C
• Wagner Dennis J
• Stinard Brian J

Classifications

• B31D2205/0064

  Stabilizing the shape of the final product, e.g. by mechanical interlocking · CPC title

• B31D2205/0058

  Cutting; Individualising the final products · CPC title

• B31D2205/0047

  Feeding, guiding or shaping the material · CPC title

• Y02W90/10

  Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics · CPC title

• B31D5/0065 Primary

  including slitting and expanding flat material · CPC title