Loose fill dunnage elements of paperboard or the like

A tubular dunnage element or paperboard or the like has a tucked or heart-shaped radial cross section, and a slanted axial cross section. The element may be compressed by opposed inward forces along any line through the center of the element. The element is suited for use as a loose fill packing material. Serrated edges cause the elements in a bed to catch on one another, resisting the tendency of a packed article to migrate through the bed to a wall of a container under the influence of vibration occurring during shipment.

TECHNICAL FIELD 
The present invention relates to loose fill packing of articles for 
shipment, and more particularly relates to a loose fill dunnage or packing 
element formed of paperboard or the like. 
BACKGROUND ART 
Safe shipment of a wide variety of articles, many of them fragile, is 
critical to modem commerce. Many articles of manufacture must be packaged 
for shipment by common carrier, and therefore may be subject to rough 
handling. When such articles are fragile, they must be protected against 
the possibility that their container may be dropped, battered, or pierced. 
A common approach to protecting fragile articles is to place the article 
in a corrugated container surrounded by packing material. Many different 
types of packing have been used to protect items being shipped in cartons. 
One method has been to use a bed of loose fill such as foam "peanuts" or 
crumpled paper. When using this method it is important that a fragile 
article not be able to migrate through the fill as it vibrates during 
transport, and eventually find its way to an outer wall of the container 
where the article is less protected. Another method has been to provide a 
structural insert such as a molded foam jacket which fits the article and 
occupies all the remaining space in the carton. Although this method is 
effective in protecting the article, it is very expensive. A fill material 
such as crumpled paper requires considerable labor to arrange the article 
in the packing material. Furthermore, the use of synthetic foams has 
become less desirable because of environmental concerns when the material 
is not easily recyclable. 
Attempts have been made to construct loose fill dunnage elements from 
paperboard. One such element consists of strips wound into cylinders, 
which are not compressible along the axis of the cylinder. Another such 
element consists of a spiral wound strip, which is difficult to make with 
enough structural strength to adequately protect fragile articles. 
Examples of U.S. Patents showing packing elements include: U.S. Pat. Nos. 
3,051,345; 5,213,867; 5,3;08,677; and 5,312,665. 
SUMMARY OF THE INVENTION 
The invention seeks to provide a dunnage material that can cushion an 
article against force from any direction, does not allow the article to 
migrate through the fill material, and may be dispensed readily around the 
article during loading. The present invention also seeks to provide a 
loose fill dunnage material that is made from recyclable material and can 
be recycled. 
In accordance with the invention, these objects are accomplished by 
providing a dunnage element made of a flexible sheet material, for 
example, paperboard, formed into elements that are compressible to cushion 
a packed article. In a preferred form the elements catch on one another to 
prevent migration of the article through a bed of the dunnage elements. 
Generally described, a dunnage element according to the present invention 
comprises an elongate strip of flexible material defining an outer planar 
surface, an inner planar surface, an upper elongate edge of the surfaces, 
a lower elongate edge of said surfaces, a first end, a second end, and a 
central portion where each of the edges extends to a position spaced below 
a line connecting points at which the edge meets the ends, the ends being 
brought together and tucked, the outer surface adjacent to the first end 
being joined to the outer surface adjacent to the second end to form a 
closed figure having a tucked portion spaced axially from the central 
portion of the strip, the figure being resiliently compressible axially as 
well as radially. 
Thus, a dunnage element according to the invention comprises a tube formed 
of flexible material, the tube having a generally heart-shaped cross 
section, a generally heart-shaped upper edge, and a generally heart-shaped 
lower edge; the upper edge being oriented such that a plane roughly 
aligned with the upper edge is inclined with respect to a central axis of 
the tube; and the lower edge being oriented such that a plane roughly 
aligned with the lower edge is inclined with respect to the central axis 
of the tube with a lowest point on the upper edge being on the same side 
of the axis as a lowest point on the lower edge. 
The preferred material for making the strip is recycled paperboard, 
although other flexible sheet materials, such as plastic, could be used. 
The shape of the strip in a preferred embodiment is a sinusoidal curve, 
and the elongate edges preferably are serrated with V-shaped cuts into the 
strip. 
The present invention also provides, using such dunnage elements, a dunnage 
system for packing articles, and a method of packing articles. Among the 
advantages of the preferred dunnage element of the invention are its 
ability to cushion articles by resiliently compressing under force applied 
from essentially any direction, and its ability to catch or lock on other 
elements to prevent the article from migrating through the dunnage 
elements of the bed. 
Other objects, features and advantages of the invention will become 
apparent upon review of the following detailed description of preferred 
embodiments of the invention, when taken in conjunction with the drawings 
and the appended claims.

DETAILED DESCRIPTION 
Referring now in more detail to the drawings, in which like numerals refer 
to like parts throughout the several views, FIGS. 1, 4 and 5 show a 
dunnage element 10 according to a preferred embodiment of the present 
invention. The dunnage element 10 is formed from a flat blank 10' of 
flexible sheet material, shown in FIGS. 2 and 3. As will be explained in 
detail below, the dunnage element 10 has a heart-shaped tubular 
configuration with serrated edges. These features allow the dunnage 
element to function advantageously as loose fill packing material. 
Each blank 10' is formed by a strip 14 of flexible sheet material having an 
outer surface 16 and an inner surface 18. An elongate, preferably serrated 
upper edge 20 and an elongate, serrated lower edge 21 extend between a 
first end 24 and a second end 25. The upper edge meets the first end at 
point 20a, and meets the second end at point 20b. The lower edge meets the 
first end at point 21a, and meets the second end at point 21b. 
The optional serrations in the elongate edges 20 and 21 preferably are 
formed by V-shaped cuts 22 into the strip 14. The V-shaped cuts 22 are 
deep enough so that the dunnage elements 10, when forming a bed, catch on 
one another to resist migration of a packed article through the bed. 
Preferably the cuts 22 are at least about 1/8 to about 3/8 deep (3-10 mm), 
and have a maximum width of about 1/8 to about 3/8 inch (3-10 mm). The 
V-shaped cuts may meet each other to form tips 26 along the serrated edges 
20 and 21. Preferably, the tips 26 are rounded so that when a person 
reaches into a bed of the dunnage elements to retrieve an article, the 
tips 26 are not so sharp as to cause discomfort. At the center of the 
strip 14, a pair of rounded cut-outs 23 may be formed for assistance in 
handling and separating the blanks 10' from the sheet 10". 
The strip 14 preferably is shaped as a sine curve, with a sinusoidal 
minimum at a center portion 30 of the strip, a sinusoidal maximum 32 
spaced inwardly from the first end 24, and a sinusoidal maximum spaced 
inwardly from the second end 25. Preferably, the general shape of the 
upper and lower edges, represented, for example, by curves through the 
tips 26, are about the same distance from one another along the length of 
the edges, and are generally parallel in this sense. The upper edge 20 in 
the preferred embodiment extends, at the central portion 30 of the strip, 
below a line A connecting points 20a and 20b, and extends, at the maxima 
32 and 33, above the line A. Similarly, the lower edge 21 in the preferred 
embodiment extends, at the central portion 30 of the strip, below a line B 
connecting points 21a and 21b, and extends above the line B at the maxima 
32 and 33. 
The height H of the strip (measured arbitrarily as the maximum vertical 
distance between points on the upper and lower edges) can vary depending 
on the nature of the articles to be packed. For a wide range of 
applications, strip heights from about one inch to about 3 inches (2.5-7.5 
cm) will suffice. The thickness of the strip also can vary depending on 
the nature of the articles to be packed, larger loads requiring a heavier 
gauge. Preferably, the gauge of the paperboard is from about 12 pt. to 
about 40 pt. (0.3-1.0 mm). 
The blank 10' preferably is made of recycled paperboard material, and is 
itself recyclable. Other flexible sheet materials could be used, for 
example, plastic, light corrugated board, or virgin paperboard. A 
plurality of blanks 10' may be die cut together in a sheet 10" as shown in 
FIG. 3, in a well known manner. The adjacent blanks 10' in the sheet 10" 
are shaped so that the upper edge of one blank nests together with the 
lower edge of the adjacent blank. It will be seen that the V-shaped cuts 
22 of the blank 10' of FIG. 2 are made by a zigzag cut 34 between blanks 
10' as shown in FIG. 3. The cut 34 creates tips 26 separated by V-shaped 
cuts in both adjacent blanks 10'. The cuts 34 separating individual blanks 
10' are perforated to allow easy separation of the blanks. 
Those skilled in the art will understand that the cut 34 can have many 
different shapes and still provide a catching action in a bed of the 
dunnage elements. For example, as shown in FIG. 8, one edge of a blank 
210' could have spaced apart triangular projections 226, resulting in 
corresponding spaced apart V-shaped cut-outs 220 in the opposite edge. 
Also, the edges could be formed with rounded scallops deep enough to 
prevent migration depending on the nature of the article to be packed, or 
spaced apart U-shaped cut-outs in one edge with corresponding rounded 
projections from the opposite edge. 
To form the dunnage element 10 as shown in FIGS. 1 and 4 from the flat 
blank 10', the first and second ends 24 and 25 are brought together into a 
tucked portion 35, with the outer surface of the strip 14 adjacent to the 
end 24 joined to the outer surface of the strip 14 adjacent to the end 25. 
The dunnage element thus forms a segment of a tube having a generally 
heart-shaped cross section, best shown in FIG. 4. When an appropriate 
paperboard material is used, no weakening lines are needed to form the 
rounded wall of the tube, although vertical score lines could be provided 
in the case of a heavier or corrugated material. 
The ends 24 and 25 may be joined by an adhesive 37, or by another fastening 
mechanism. For example, a hot melt adhesive may be applied soon prior to 
bringing the ends together, and the ends held until the adhesive sets. 
Alternatively, a heat sensitive, thermosetting adhesive may be applied to 
the blank earlier, and the ends heated as they are brought together and 
held until the adhesive sets. Also, mechanical fastening means are 
possible, such as punch-through locking tabs of a type known in the art, 
or engagement of a separate slotted tab with aligned slits cut into the 
ends 24 and 25, or staples, clips or the like. 
A feature of the shape of the dunnage element 10 is the slanted or angled 
orientation of the edges 24 and 25 with respect to a vertical or central 
axis E of the heart-shaped tube. This configuration results in the 
preferred embodiment from the sinusoidal shape of the strip 14. Thus, it 
will be seen in FIG. 5 that a radial projection C of the upper edge point 
20a inward from the tucked ends passes above the central portion 30 of the 
strip, and a radial projection D of the lower edge point 21a inward from 
the tucked ends intersects the central portion 30. 
It also will be seen that a plane F roughly aligned with the upper and 
lower edges is inclined with respect to the central axis E of the tubular 
element 10 such that the lowest points on both edges are on the same side 
of the central axis. It should be understood that planes roughly aligned 
with the upper and lower edges need not be parallel. The configuration of 
the tubular member also is characterized in the preferred embodiment by a 
shortest diameter G, taken parallel to the tucked and joined ends 24 and 
25, that is smaller than a longest diameter J, taken across the tucked and 
joined ends 24 and 25, as shown in FIG. 4. In the embodiment shown, the 
shortest diameter G greater than the height H. The diameters may vary 
depending on the nature of the load to be applied. Packing larger, heavier 
articles generally requires smaller diameter dunnage elements 10. 
A particularly preferred dunnage element includes a strip made of 20-22 pt. 
paperboard (0.50-0.56 mm) that has a height H of about 1.25 inches (3.2 
cm), a shortest diameter G of about 1.1 inches (2.9 cm), a longest 
diameter of about 2 inches (5 cm), and V-cuts 22 of depth and width 
between tips both about 0.25 inch (6.4 mm). 
Those skilled in the art will understand that automatic folding and gluing 
machinery using known techniques may be constructed to create the dunnage 
element 10 from the sheet of blanks 10" in a mass production setting, but 
is not required to make the preferred dunnage elements embodying the 
present invention. Also, it should be noted that terms such as "vertical," 
"upper," "lower," and the like are utilized only to provide a relative 
frame of reference, and not to refer to any absolute direction within the 
earth's gravitational field. 
As shown diagrammatically in FIG. 6, an article 40 may be packed in a 
carton 42 within a bed 45 of dunnage elements 10. The purpose of the bed 
45 is to occupy the empty space in the carton, hold the article 40 near 
the center of the carton 42, and act as a shock absorber to cushion the 
article. If the nature of the article is such that only space occupation 
is needed, the dunnage elements may be made without the serrated edges. 
The serrated edges cause the elements 10 to catch on one another, 
resisting the tendency of the article to migrate through the bed to a wall 
of the carton under the influence of vibration that occurs during 
shipment. Deeper serrations may be required for heavier articles and 
shallower serrations may be acceptable for light loads. The dunnage 
elements 10 protect best against migration if the bed is under pressure. 
Preferably, the carton should be slightly overfilled with the dunnage 
elements, and pressure applied on the bed when the carton's closure flaps 
are folded down and secured. 
The cushioning function of the bed is made particularly effective by the 
combination of the tucked or heart-shaped radial cross section, and the 
slanted axial cross section of the tubular dunnage element 10. The element 
10 may be compressed by opposed inward forces along any line through the 
center of the element, and it will tend to resiliently spring back. In 
contrast, a right cylinder is compressible from the sides, but not along 
its central axis. The dunnage element according to the present invention 
is resiliently compressible along its central axis or any other axis. The 
tucked portion provides more springiness upon compression, and helps the 
element resist fully collapsing under pressure. This structural integrity 
plus cushioning action results in a bed of paperboard dunnage capable of 
protecting fragile articles during shipment. 
FIG. 7 shows an alterative embodiment of the invention. A dunnage element 
100 is formed from a blank 110' comprising a V-shaped strip 114 of 
paperboard. The strip has an upper edge 120 and a lower edge 121 
connecting a first end 124 to a second end 125, analogous to the first 
embodiment described above. The area near the "point" of the V-shaped 
strip forms a central portion 135. It will be understood that when the 
strip 114 is formed into a tucked tube with a heart-shaped radial cross 
section in the manner described above, a slanted axial cross section will 
result. Although the edges 120 and 121 are shown as being smooth, 
serrations may be added. The blanks of FIG. 2 and FIG. 7 are only examples 
of many blanks whose shape will provide a compressible dunnage element 
when formed to have cross sections generally as shown in FIGS. 4 and 5. 
Those skilled in the art will understand that variations and modifications 
to the preferred embodiments described above can be made without departing 
from the scope of the invention as defined in the appended claims.