Note: Descriptions are shown in the official language in which they were submitted.
Z168979
WO 95/07225 PCTIUS94/10209
1
1 METHOD AND APPARATUS FOR PRODUCING INDIVIDUAL
2 ROLLS OF PACKING MATERIAL
3 BACKGROUND OF THE INVENTION
4 Field Of The Invention
The present invention relates in general to the methods and apparatus to
manually or
6 automatically expand a slit paper type of packaging material and to
apparatus for forming the
7 expanded slit paper into spiral cylinders of cushioning materials to be used
in packaging.
8 Brief Description of the Drawing_s
9 The objects and advantages of the instant invention will be apparent when
the specifica-
tion is read in conjunction with, the drawings, wherein:
11 FIGURE 1 is an end view of a representation of the spiral cylinder of the
instant inven-
12 tion;
13 FIGURE 2 is a partial end view of the expanded paper forming the spiral
cylinder;
14 FIGURE 3 is a side elevation of an alternate apparatus for spiraling
expanded sheet
material into cylinders for use as void fill material;
16 FIGURE 4 is a top view to the expansion machine of the instant invention;
17 FIGURE 5 is a side view of the expansion machine of FIGURE 4;
18 FIGURE 6 is a side view of the dual paper positioning in conjunction with
the expansion
19 machine of FIGURE 4;
FIGURE 7 is a schematic side view of a feed roll housed within a container;
21 FIGURE 8 is front elevational view of the container of Figure 7;
22 FIGURE 9 is a side view of another embodiment of a delivery system, showing
a feed roll,
23 restraining rolls, and a tear bar;
24 FIGURE 10 is a side view of a further embodiment of a delivery system, and
FIGURE 11 is a fragmentary illustration of tensioning mechanism for a
restraining roll;
26 FIGURE 12 is a side view of an additional embodiment of a delivery system;
27 FIGURE 13 is a schematic illustration of a two roll delivery system;
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WO 95/07225 PCT/US94/10209
2
1 FIGURE 14 A-F are schematic illustrations of an alternate embodiments of a
two roll
2 delivery system;
3 FIGURE 15 is a fragmented illustration of a two roll delivery system using
guide wheels;
4 FIGURE 16 is a fragmented illustration of an alternate two roll delivery
system using fila-
ment wrap;
6 FIGURE 17 is an alternate emobodiment of Figure 16;
7 FIGURE 18 is a schematic illustration of a slitting system;
8 FIGURE 19 is a top view of the knives of Figure 18.
9 Detail Descripiton of the Invention
The instant disclosure relates to the method and equipment for the expansion
of an expan-
11 dable material, preferably slit, recycled paper, as a packing material and
to the use of the ex-
12 panded material as a void fill in packaging.
13 The paper, once expanded creates semi-rigid peaks or lands. These peaks are
similar to a
14 spring in that once force is applied and removed, they return to their
original positioning, provid-
ing the elastic limit is not exceeded. The elastic force created by the
resistance of the paper fibers
16 slows the acceleration of the force. The work performed by movement of the
semi-rigid peaks as
17 a force is applied by an article, is the elastic potential energy of the
expanded material. The yield
18 point is the point beyond stress when a large increase in strain occurs
with almost no increase in
19 stress.
The use of expanded paper in widths of 1/2 inch increments from 1/2 inch to 6
inches and
21 unrolled, unexpanded paper lengths varying from 3 to 24 inches was tested
as a void fill. The
22 material was found to retract to some degree if not bound at the ends or
wrapped around an ar-
23 ticle, making optimum expansion difficult to achieve. The slit pattern can
be varied with op-
timum results being obtained with patterns which form hexagonal cells. With
the identical paper,
24
load bearing capacity is dramatically increased with the hexagonal pattern, as
compared with a
26 diamond cell yielding slit pattern. By winding the paper in the form of a
cylinder, the tension on
27 the expanded paper can be maintained without the use of adhesives or the
like, since the cells
28
'216$9?9
WO 95/07225 PCTIUS94J10209
3
1 "interlock", thus preventing unwinding of the completed cylinders. The sheet
material decreases
2 in width during the expansion step and the dimensions of the cylinder are in
terms of final dimen-
3 sion of the finished cylinder. Cylinders less than 1 inch in length having a
tendency to unravel,
4 due to insufficient interlocking of cells, with the problem increasing with
decreasing length.
Cylinders under 1 inch in diameter offer insufficient cushioning effect for
general applications.
6 In terms of the correlation between unexpanded flat sheet material and
finished cylinders, one
7 square foot of sheet material will produce about two and three quarter
finished cylinders, as one
8 2x2 cylinder equals .376 square feet of sheet material. Obviously, the
tighter the cylinder is
9 wound, the greater the amount of sheet material required to form a cylinder.
Thus, the
aforenoted correlation between sheet material square feet and cylinder
diameter and length, is a
11 measure of how tightly the cylinder is wound. Although the tighter the
cylinder, the firmer the
12 cushion effect which is achieved, winding the cylinder too tightly will
have the effect of remov-
13 ing air from the cylinders and lessening their cushioning qualities. Hence,
winding forces on the
14 slit paper material and the quantity of slit paper material used to produce
a cylinder are critical.
Thus, the cylinders can be customized to meet specific system requirements.
16 Expanded paper cylinders were attached to hand-made cardboard cores and
wound around
17 the cores. Cylinders ranging in size from about 1X1 inch to 6X6 inches were
tested. All sizes
18 worked, with the 2X2 size being most effective. The solid core presented a
rigid surface and
19 lacked cushioning for side impact.
Coreless cylinders were formed using hand powered winders. The coreless
cylinders were
21 better at absorbing impact at the sides and edges of the cylinders, than
the rigid core centered
22 cylinders. However, the number of square feet of sheet material required to
produce a cubic foot
23 of coreless cylinders was higher than optimally desired, from a cost
standpoint. On the other
24 hand, the coreless cylinders provided highly effective cushioning
characteristics.
Using a small hand winder, cylinders were produced with a hollow core and
characterized
26 by a 40 square feet of unexpanded sheet material to 1 cubic foot of
cylinder. The hollow core
27 cylinders provided excellent impact and vibration protection. The hollow
center spiral wound ex-
28
WO 95/07225 PCT/US94/10209
216857~
4
1 panded paper provided a greater degree of soft cushioning than was provided
by the tightly 2 wound coreless cylinders of expanded paper. The cylinder of
expanded paper with a hollow core
3 center provided an excellent compromise between excessive use of raw
material in the tightly 4 wound cores and lack of side impact protection and
added expense associated with the production
of expanded paper cylinders with a rigid core.
6 To form the cylinder of the instant disclosure the slit paper is expanded
and rolled into a
7 cylindrical spiral, having a predetermined diameter and length based on end
use. As disclosed, as
8 the paper is expanded, it forms raised cells which, when rolled, interlock
with cells in adjacent
9 layers as the paper spirals outward. The interlocking of the cells
eliminates the need to secure the
cylinders, thereby making them immediately ready for use. The spiral cylinder
40 of Figure 1 is a
11 conceptual illustration of an end view, showing the concept of the
interlocking cells raised from
12 the land, however for clarity, rectangles are used to depict the cells
formed by the row spacing 44
13 and the slit spacing 42. Detailed description and illustration of the
expanded and unexpanded
14 paper are disclosed in PCT/US/93/02369 published 30 September 1993.
In Figure 2, a portion of the spiral cylinder 10 is illustrated which more
accurately depicts
16 the formation of the cells. The actual cells cannot be seen in the side
view of Figure 2, however
17 the material forming the cells is depicted. The row spacing 38a and 38b and
the slit spacing 36
18 are warped, thereby forming the peaks and valleys which interlock with one
another.
19 The self-locked cylinder provides maximum protection of an article by
absorbing the
energy created by the impact. The absorbency is achieved by placing the layers
in a position to
21 force interaction between the cells. The positioning of the paper in a
spiral prevents the paper
22 from turning back on itself or twisting, which lessens the cushioning
effect from the cell interac-
23 tion. The spiral configuration is not only the most economical and easy to
produce, it is struc-
turally the most effective. The force applied to the cylindrical elastic body
compresses in toward
24
the center, with each interior layer creating an elastic force to return to
its original position. The
26 interaction of the cells additionally distributes the impact force through
the entire cylinder,
27 thereby providing increased protection of edge or corners of the object
being shipped. This is un-
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1 like the commonly used styrofoam peanuts which act independently. With the
styrofoam peanuts,
2 if the corner of an item receives the main force of impact, the peanuts
separate, thereby allowing
3 the item to slide within the box. The interlocking of the cells of the
cylinders not only interlocks
4 each individual cylinder but locks the cylinders to one another, preventing
slippage of the item
5 within the box. '
6 The spiral cylinder 10 can be varied in size dependent upon the intended
use. The
7 preferable size is approximately 2 inches in length and 1 1/2 - 2 inches in
diameter. The hollow
8 core cylinders provide good packaging protection from all angles of impact
and utilize the square
9 footage within the core most efficiently. Desired results are obtained with
paper weight of 70
pound per 3000 square feet of recycled Kraft, 100% post consumer recycled
paper and 3.2 inches
11 by 16 inches (52 square inches of unexpanded slit paper) produces one
hollow core cylinder. One
12 hundred twenty cylinders, representing 40 square feet of unexpanded paper,
filled one cubic foot
13 volume as opposed to 210 tightly wound coreless cylinders being required to
fill the same volume.
14 Cylinders with a rigid cardboard core required 110 cylinders to fill one
cubic foot. One cubic
foot of unexpanded 70 lb. slit paper produces 37.2 cubic feet for void filling
purposes when utiliz-
16 ing the hollow core method.
17 Figure 3 is a side elevation of an apparatus for spiraling expanded sheet
material into
18 cylinders for use as void fill material. In the embodiment of Figure 3,
expanded sheet material
19 800 is fed between the upper moving belt 802 and the lower moving belt 804.
The upper moving
belt 802 is driven and carried by the upper belt drive roll 806 in the counter
clockwise direction,
21 as indicated by directional arrow 801. The lower belt drive roll 808
carries and powers the lower
22 moving belt 804 in the clock wise direction, as indicated by directional
arrow 803. The upper belt
23 803 is tensioned between the drive roll 806 and the cooperative roll 805.
The tension plate 810 is
24 biased against the belt 802 by the tension springs 814. Similarly, the
lower belt 804 is tensioned
between the drive roll 808 and the cooperative roll 809. The tension plate 812
is biased against the
26 belt 804 by the tension springs 816.
27
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WO 95/07225 PCT/US94/10209
~r~~~~=~~
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1 The lower belt 804 rotates opposite the upper belt, thereby driving the
forming cylinder
2 820 in the direction indicated by directional arrows 819. The upper belt 802
is rotated at seven
3 times the speed of the lower belt 804, thereby causing the leading edge 824
of the expanded sheet
4 800 to drag and curl under. As the sheet progresses in the direction of
arrow 819, the curling ef-
fect is continued forming partly formed cylinder 820. The curling or spiraling
effect continues
6 until a fully formed cylinder 822 is produced and delivered to a receiving
region, not shown.
7 Figures 4 and 5 illustrate the expansion machine 700 which rapidly produces
optimum ex-
8 pansion of the slit paper 750. The paper is fed from a storage roll, not
shown, to the upper and
9 lower drive rollers 706 and 708, where it is placed between the rollers 706
and 708. The paper
storage roll can be placed at any point along a 1000 arch from the drive
rollers 706 and 708, using
11 the point directly perpendicular from the drive rollers 706 and 708 as the
00 point. Both the upper
12 drive roller 706 and the lower drive roller 708 are covered with a friction
material, such as shrink
13 tubular material made of a heat shrinkable polymer, as for example
polyvinyl chloride. Alterna-
14 tively, a rubber spray or painted coating can be used. Additionally vinyl
tape covered rollers and
rubber rollers can be used. Abrasive coatings tended to produce some
scratching of the paper and
16 formation of dust due to the action of the abrasive material on the paper.
17 There is no theoretical upper limit to the amount of friction caused by the
roller fiction
18 covering, except that damage to the paper must be avoided. Therefore, the
use of a coarse
19 material is to be avoided.
The tension between the drive rollers and the expansion rollers must be
sufficient to open,
21 or expand the slit paper, but not sufficient to tear the paper. Typically,
with a 30 pound paper,
22 2.5 oz. of force per linear inch, can be applied and with 70 pound paper, 5
oz. of force can be ap-
23 plied. The expansion should be sufficient to not only expand the paper, but
also to crack some of
24 the fibers, thereby decreasing the tendency of the paper to return to its
unexpanded form. With
the aforenoted 70 pound paper, it required a .011 hp motor to deliver paper at
a rate of 300 inches
26 per minute, expanded one linear inch.
27
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WO 95/07225 2168979 PCT/US94/10209
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1 Utilizing a 20 by 36 inch sheet of the aforenoted unexpanded 70 pound paper,
with one
2 end secured in a rigid fixture across its entire width, the paper was
suspended vertically and a
3 force was applied to expand the paper. A force of about 50 ounces, that is,
2.5 oz. per inch, in-
4 itiated the expansion of the paper and 3 oz. per linear inch opened all of
the paper cells. 5 oz. per
linear inch opened all cells fully and yielded cell wall fiber tearing which
aids cell walls to
6 remain open after the expanded paper is released in the open position. A
force of 7.5 oz. expanded
7 the paper and tore it after 10 seconds of continued stress. 10 oz. per
linear inch opened the cells
8 and immediately tore the paper. The use of about 5 oz. was thus shown to
provide the optimum
9 results.
The lower drive roller 708 is driven by the motor 726 through the rotation of
the motor
11 gear 716 and drive gear 714. The rotation created by the motor 726 is
transmitted along motor
12 shaft 724 to the motor gear 716 where it drives the drive belt 718, which
in turn rotates the drive
13 gear 714. The motor gear 720, also connected to the motor shaft 724, drives
the expansion belt
14 722, which in turn rotates the expansion gear 710. Due to the spacing of
the motor gear 716 and
the motor gear 720 along the motor shaft 724, an expansion shaft 712 is
generally provided be-
16 tween the expansion gear 710 and the upper expansion roller 702 and lower
expansion roller 704.
17 The drive gear 714 is provided with 20 teeth as compared to the expansion
gear 710 which has 14
18 teeth. The difference in the number of teeth changes the rotation speed of
the upper expansion
19 roller 702 and lower expansion roller 704 as compared to the upper drive
roller 706 and lower
drive roller 708, allowing the motor shaft 724 to rotate at a single speed.
The differential can be
21 obtained by a number of methods known in the prior art and the foregoing is
not intended to
22 limit the scope of the invention. The speed differential between the upper
and lower expansion
23 rollers 702 and 704 and the upper and lower drive rollers 706 and 708 is
critical as it provides the
24 expansion of the slit paper 750. The slit paper 750 is being removed from
the expansion machine
700 faster than it is entering, thereby forcing the slit paper 750 to expand.
The speed differential
26 between the expansion rollers 702 and 704 and the drive rollers 706 and 708
must be calculated to
27 provide the required amount of expansion based on the weight of paper and
end use. In the gear
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2168>79
8
1 assembly as illustrated in Figures 4 and 5, the expansion gear 710 and drive
gear 714 can be
2 changed to provide a increase or decrease in the speed differential. Other
methods of changing the
3 speed differential can be obtained and are known in the prior art. 4 The
spacing of the expansion rollers a distance of about 6 inches from the drive
rollers
produced some binding in the middle of the paper, apparently due to the
contraction of the paper
6 which coincides with the expansion of the paper in thickness and length. A
space between the ex-
7 pansion and drive rollers of about 11.25 inches worked well for 19.5 inch
rolled paper. With 3
8 inch wide papcr, a minimum of 4 inches of separation between the roller
sets. The distance be-
9 tween the drive rollers and the expansion rollers varies proportionally with
the width of the unex-
panded paper.
11 The expansion device can be used to produce expanded product for use
directly as a wrap-
12 ping material. The automated roll dispenser provides for immediate use of
the expanded paper
13 minimizing space requirements while yielding maximum packaging usage by
allowing the user to
14 pull tightly during the wrapping process by stopping or braking when
needed. At the end of wrap-
ping, prior to tearing, the foot pedal is released and the automated expander
brakes for final pull-
16 ing and tearing. This leaves the process of maximum stretch intact for
greatest packaging protec-
17 tion. An electronic unit can be employed to deliver measured quantities of
expanded paper.
18 Breaking at the end of the delivery provides for the user to tear the
desired length of paper from
19 the roll of paper. Alternatively, a cutting blade can be used to severe the
delivered quantity of
paper from the remainder of the roll.
21 The upper expansion roller 702 and the lower expansion roller 704 are
covered with a
22 material which provides the affect of fingers. The covering must grip the
unopened slit paper
23 750, without ripping the paper, and pull it open through use of the
differential speed between the
24 expansion rollers 702 and 704 and the driver rollers 706 and 708. The use
of soft rubber covered
rollers works to produce even expansion over the width of the paper. However,
deformation of
26 the paper can be experienced, in the form of crushed cells. That is, at the
point of contact with
27 the pair of expansion rollers, the expanded cells can be crushed by the
rollers. The use of open
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WO 95/07225 PCT/US94/10209
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1 cell and light foam can work to provide the required expansion. However, low
density, open cell
2 foam have a life span which is shorter than optimally desired. When soft
bristled brushes of the
3 type employed in photocopy machine, were used, some difficulty was
experienced in starting the
4 expansion process. Harder bristled brushes cause some trouble in releasing
the paper. Optimum
results were obtained with medium stiff bristles cut to approximately 1/8 inch
in length. Bristles
6 can be made of metal wire, such as carbon steel, stainless steel, brass,
bronze and a variety of
7 bristle dimensions are commercially available.
8 The preferred material is a nylon hook fiber of the type found in hook and
loop fasteners
9 of the type sold under the trademark VELCRO. The use of a set of rollers
faced with hook ended
fibers provided the required expansion without distortion of the expanded
paper or deterioration
11 of the rollers. Unlike, relatively firm foam covered rollers, the hook
fibers did not crush the ex-
12 panded cells as they passed between the expansion rollers. It should be
understood that the role of
13 the expansion rollers is critical in that they must be able to grip and
pull the paper so as to impart
14 a speed of travel to the paper which is greater than the speed of the paper
when it passes through
the drive rollers. This requirement is in conflict with the need to permit the
expanded paper to
16 pass between the rollers without the expanded cells being crushed.
17 An alternate embodiment to the expansion device of Figures 4 and 5 is
illustrated in Figure
18 6. The multi roll expander 600 operates on the same basis as the expansion
device 700. The ex-
19 pander 600 is provided with a paper support unit 630 which is provided with
at least one retaining
area 638 to receive the paper roll 634. The retaining area 638, as illustrated
herein, is a notched
21 portion which receives a bar 636 which is placed through the core of the
paper roll 634. The ex-
22 pander 600, as illustrated, holds two rolls of paper 632 and 634 in
retaining areas 638 and 640,
23 however additional rolls can be added. The paper 642 from roll 632 is fed
into the bottom roller
24 set 620 and the paper 644 from roll 634 is fed into the top roller set 610.
The top roller set 610
and bottom roller set 620 are each designed as described in Figures 4 and 5.
26
27
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WO 95/07225 2168979 PCT/US94/10209
1 One embodiment of a manual expander system 1110 is shown in Figure 7,
wherein the roll
2 1120 is retained within a container 1118. The sheet material 1112 is
expanded by drawing the
3 sheet material 1112 directly from the supply roll 1120 at a rate which is
greater than the rota-
4 tional speed of the supply roll 1120. The control of the rate of supply of
sheet material 1112 from
5 the supply roll 1120 can be achieved by limiting the rotational speed of the
supply roll 1120
6 directly, as for example, through the use of a friction bearing on the axle
1114. This is not,
7 however, the optimum method, as the friction bearing, or other method used
to provide tension,
8 must be frequently altered to coincide with decrease in the supply roll 1120
sizing or addition of a
9 new supply roll 1120.
10 The supply roll 1120 and the associated elements can conveniently be
supported by a frame
11 1116, which can be in the form of a pair of X members. The ends of the legs
of the frame 1116
12 can be in contact with the side walls, or positioned in the corners, of the
container 1118. The con-
13 tainer 1118 is provided with a cut line 1115. The cut line 1115 is
preferably provided with a ser-
14 rated, metal portion to easily tear the paper at the desired length. The
container 1118 can be a cor-
rugated cardboard box or lightweight wood. Each of the embodiments of Figures
9, 12 and 13 can
16 be employed within the container 1118.
17 Preferably, the manual expander system 1110 is provided with rollers to
expand the sheet
18 material 1112. In the embodiment of Figure 9, expansion is achieved by
passing the sheet material
19 between a guide roller 1124 and a secondary roller 1126. A pawl (not shown)
engages the teeth of
the wheel 1134, preventing counter-clockwise rotation. Any other convenient
rotation direction
21 limiting mechanism can be used. The guide roller 1124 is prevented from
freely turning by means
22 of a friction bearing, such as illustrated in Figure 11. The sheet material
1112 is held firmly
23 against the guide roller 1124 by the secondary roller 1126, as shown in
Figure 10. By holding the 24 sheet material 1112 against the guide roller
1124, the secondary roller 1126 controls, or restricts,
the speed of movement of the sheet material 1112 through the drag of the guide
roller 1124.
26 Where thc speed of rotation of the supply roll 1120 is controlled, such as
in Figure 7, the guide
27 roller 1124 can be free rolling.
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WO 95/07225 2168979 PCT/US94/10209
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i As the sheet material 1112 is pulled manually from the supply roll 1120 it
is expanded as it
2 passes between the guide roller 1124 and secondary roller 1126. When the
desired length of
3 material has been withdrawn it is torn from the remainder of the sheet
material 1112. The tearing
4 action is greatly facilitated by drawing the expanded sheet against a tear
bar 1132. The tear bar
1132 can be a threaded rod or other rough surfaced member, such as the jagged
member 1115, il-
6 lustrated in Figure 8. The expanded sheet material has an irregular surface
which engages the sur-
7 face of the tear bar 1132, and provides for the controlled tearing of the
sheet material.
8 The manual expander system 1110 can be mounted on a table or floor, or
suspended from
9 an overhead support, for downward dispensing of expanded paper, as
illustrated in Figure 9. The
supply roll 1120, or rolls, can be offset from the final direction travel of
the paper within a 3000
11 arc, with the axle 1114 of the supply roll 1120 parallel to the axis of the
guide roller 1124 and
12 secondary roller 1126. The sheet material 1112 can be provided by multiple
rolls, or a multi-ply
13 roll, with the limitation being the strength of the operator to draw paper
against the required ten-
14 sion resistance.
In the embodiment of Figure 10, the manual expander system is configured as
for a floor
16 or table set up. The sheet material 1112 leaves the supply roll 1120 and is
fed between the secon-
17 dary roller 1126 and the guide roller 1124. The sheet material 1112 passes
along to the retaining
18 bar 1140 where it is dispensed, expanded, until a sufficient length is
achieved. The spring loaded
19 retaining bar 1140 prevents the paper 1112 from pulling toward the guide
and secondary rollers
1124 and 1126 due any clockwise motion of the supply roll 1120.
21 Preferably, the guide roller 1124 is friction tensioned by means of the
mechanism of Figure
22 11. A friction plate 1152 is mounted adjacent the guide roller 1124 and
attached to the wall 1156.
23 The guide roller 1124 is mounted on a shaft 1150 which is passed through
the friction plate 1152
24 and the wall 1156 of the carrier for the manual expander system 1110. At
least the end of the
shaft 1150 is threaded to receive a wing nut 1158. The shaft 1150 passes
through the wall 1156
26 and receives a spring 1154, which is secured onto the shaft 1150 with the
wing nut 1158. The
27 spring 1154 must have a diameter less than that of the wing nut 1158 to
maintain the spring 1154
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12
1 in place. The wing nut 1158, when tightened, applies a selected amount of
pressure to the spring
2 1154, thereby pulling the roller 1124 against the friction pad 1152. The
pressure can be easily
3 regulated to maintain the desire amount of turning resistance. The force
applied to the paper
4 must be within a relatively controlled range. The use of too much force will
tear the paper rather
than produce controlled expansion, and too little pressure will unwind the
paper without expan-
6 sion. The preferable expansion force is in the range from about 3 oz. to
about 7.5 oz. and
7 preferably about 5 oz. per linear inch of paper width.
8 Tensioning can also be provided by pressing together a pair of rollers
through which the
9 paper travel, thereby tying the rate of movement of the paper to the
rotational speed of the guide
rolls, and restricting the rotational rate of the rolls. Tensioning can also
be regulated by varying
11 the positions of a pair of guide rolls relative to the travel of the paper.
As the position of at least
12 one guide roll is moved such that the paper contacts an increasing degree
of the perimeter of the
13 guide rolls, the tension is increased. The paper acts to force apart the
two guide rolls 1124, and
14 1126 of Figure 9. In the embodiment of Figure 10, the guide rolls displace
the direction of travel
of the paper to a greater extent than in the position illustrated in Figure 9,
thereby providing an
16 higher degree of tension on the paper. Additionally, surface tension can be
applied by a band
17 with a weight or spring. The friction device can be a friction clutch,
pneumatic, magnetic or
18 hydraulic tension mechanism. The magnetic tensioning mechanism is sold as a
magnetic particle
19 tensioning brake. The exact form of the tensioning mechanism is not
critical, and any commer-
cially available mechanism can be used.
21 The portion of expanded paper between the supply roll 1120 and the cut end
tends to
22 retract once it has been released from the tension of being pulled. The
retraction of the leading
23 edge of the paper can be restricted by a roller 1160 as shown in Figure 12,
or the aforenoted 24 spring loaded retaining bar 1140, of Figure 10. The
springs enable the paper to force the gripping
fingers aside during expansion but pull the gripping fingers into tighter
engagement with the
26 paper if the paper is pulled in the reverse direction. The retraction
prevention mechanism has its
27 paper contacting surface covered with a surface for gripping the expanded
paper. The covering
28
CA 02168979 2005-05-24
WO 95107225 PCT/US94/10209
13
I must grip the unopened slit paper when moving in the retract direction,
without ripping the paper,
2 when the user is pulling it off of the feed roller. The material used to
grip the paper can be
3 angled to provide the unidirectional travel of the paper, as compared to
being on a spring loaded
4 mechanism which can give way during the paper expansion step. The gripping
mechanism can be
a plurality of monofilament polymer strands mounted in an inclined position
relative to the travel
6 line of the paper. The incline permits the paper to slid past the gripping
mechanism in one direc-
7 tion, but results in the engagement of the strands and the cells during
travel in the reverse direc-
8 tion.
9 The sheet materiat 1112 must not be deformed, through the crushing of cells,
while the ex-
panded paper is passing through the retraction prevention rnechanism. At the
point of contact
11 with the pair of retraction prevention rollers, either the spring loaded
bar or the single retraction
12 prevention roller, the expanded cells can be crushed by the retraction
mechanism. The use of open
13 cell and light foam can work to provide the required expansion.
14 As noted heretofore, the preferred material is a nylon hook fiber which
does not crush the
expanded cells as they passed under the retraction mechanism 1140. The barb of
the hook is
16 oriented in the lcading position such that the barbs engage the slits in
sheet material during the
17 retraction of said paper, but permit the sheet material to slid past during
the unwind/expansion
18 step. In the modification of Figure 15, the bar 1140 is spring biased
toward the sheet such that
19 unwinding movement causes the bar to move away from the paper. Conversely,
a tendency of the
paper to rcwind or retract, pulls the bar toward the paper. Thus, the hooks
dig into the slits
21 during rewinding, but freely permit the paper to move in the unwind
direction.
22 Figure 12 illustrates a mechanism in which the retraction prevention is
provided by a guide
23 ro111160 and bracing roll 1162 positioned on either side of the paper 1112.
The guide roll 1160 is ;
24 provided with the same type of hook filaments, bristles, or the like, as
provided for bar 1140 to
prevent crushing the paper. Reverse travel is prevented thirough the use of
any convenient means
20 for limiting the guide roll 1160 to a single direction rotation.
Conveniently, a ratchet mechanism
27
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WO 95/07225 PCT/US94/10209
2168979
14
1 such as wheel 1134, illustrated in Figure 9 can be used. The bracing roll
1162 maintains the paper
2 1112 against the guide roll 1160 and can be either free rolling or provided
with reverse travel
3 means.
4 In another embodiment, the amount of paper which is delivered for expansion
can be in-
creased by using multiple layers of paper. The only change in the system is
the use of a plurality
6 of feed rolls to supply slit paper to the system. Alternatively, the sheet
material 1112 can be in the
7 form of multi-layers of the slit expanded sheet material on a single roll.
Thus, the requirement
8 for the simultaneous feeding of multilayers can be achieved through the use
of a multi-ply, single
9 roll or a plurality of feed rolls. Each method has its advantages. The multi-
roll allows the choice
of using single ply rather than multi-ply. The use of multiple rolls does,
however, take more space
11 than the multi-ply, single roll system. As shown in Figure 13, a first roll
1170 can be positioned
12 above a second roll 1172. Paper is feed simultaneously between two guides
rolls, 1124 and 1126
13 which serve as a tensioning mechanism, as previously described. The output
1178 is two layers of
14 expanded sheet material.
When the (illing material is wrapped around an article, it is in the form of a
plurality of
16 layers of interlocked expanded sheets due to the land areas of adjacent
sheets of the layers of
17 sheets nesting and interlocking with each other. Contraction of the
expanded sheets is thus
18 prevented or at least restricted.
19 The length of the slit and the ratio of the land intervals between slit
affects the dimensions
of the polygons which are formed during the expansion step. The higher the
ratio of slit length to
21 interval length the greater is the maximum angle which can be formed
between the plane of the
22 sheet and the planes of the land areas. The greater the uniformity of the
shape and size of the
23 formed polygonal shaped open areas and the angle to which the land areas
incline relative to the
24 flat sheet, the greater is the degree to which interlocking of land areas
can be achieved. Interlock-
ing of land areas, that is, the nesting of layers of sheets, reduces the
effective thickness of the
26 sheets. However, the net effect is still a dramatic increase in effective
sheet thickness. For ex-
27 ample, .008 inch thick paper having a slit pattern of a 1/2" slit, 3/16"
slit spacing, and 1/8" row
28
21.68979
WO 95/07225 PCTIUS94/10209
1 spacing, produces a 1/4" by 3/16" land which can expand to under about one
quarter of an inch
2 thickness and will have a net effective thickness for tWo layers, when
nested, of about .375 inches.
3 It is noted that the land width is double the width of the legs. The net
effect is a useful thickness
4 expansion of roughly at least 20 times the unexpanded thickness of the
paper.
5 The nesting of adjacent layers can occur to an excessive extent, as for
example, where ab-
6 solute uniformity of expansion exists in adjacent layers, and the adjacent
layers merge or com-
7 mingle with each other to a second layer adds to the combined thickness of
two sheets only to the
8 extent of the unexpanded thickness of the second sheet rather than the
expanded thickness of the
9 second sheet. Stated another way, where merging takes place rather than
limited nesting, the
10 cumulative effect of the addition of successive layers of sheets is based
on a thickness increase
11 relative to the unexpanded thickness of each successive sheet. The desired
net effect is a nesting
12 where the land of one layer drops into the cell of the adjacent layer only
to the extent necessary
13 to provide interlocking, that is, preclude relative motion of the layers.
The overall object is to
14 prevent slippage between adjacent layers, while maximizing the cumulative
thickness of the
15 layered material. Thus, on the one hand, the adjacent layers should
interlock while on the other
16 hand the adjacent layers should not interlock in order to maximize the
thickness of the expanded,
17 multilayered product.
18 The balance between interlocking and maximizing thickness can be achieved
by offsetting
19 the adjacent layers or offsetting the slit pattern and reversing the
direction of offset on layer rela-
tive to the adjacent layer. The offsetting of the slit pattern can be relative
to a multi-ply, single
21 roll, in which adjacent plies are offset, as well as to a multi-ply
configuration formed from two
22 rolls of single ply material, as described above.
23 The parallel rows of individual slits preferably form an angle with the
longitudinal axis
24 (the opposing edges of the sheet) in the range from about 89.5 to 87
degrees. This produces the
aforementioned offset. By alternating the adjacent rows the net offset between
the parallel rows
26 of slits of adjacent layers forms an angle in the range from about 10 to
about 60. That is, the line
27 of slits of adjacent plies cross each other at an angle in the range from
about 10 to about 60. As
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WO 95/07225 PCT/US94/10209
~~6075
16
1 shown in Figure 13, two feed rolls 1170 and 1172 can be provided. By having
one roll unwind
2 counterclockwise and the other clockwise, the aforenoted crossing of the
lines of slits of adjacent
3 rolls occurs, producing the desired blend between interlocking and
maximizing of expanded thick-
4 ness.
The use of guide rolls to regulate the tensioning of the delivery system, is
shown in Figures
6 14A through 14F. In Figure 14A, no tension is provided on the sheet 1180,
passing between the
7 guide rolls 1182 and 1184. The rotation of the two guide rolls relative to
each other, as shown in
8 Figure 14B, produces moderate tension which is increased with the rotation
of the relative roll
il-
9 positions as shown in Figures 14C and 14D. As the path of the paper becomes
more tortuous, as
lustrated in Figure 14E and F, the tension increases.
11 The expansion drive rollers can be adjusted to alter the space between the
rollers. In this
12 manner, a required balance can be attained between compression of the paper
sheet between the
13 rollers and minimization of the crushing of the cells of the expanded
paper. Once the process has
14 been started and the paper is expanded, the Velcro hooks can grab and pull
the expanded cells
with little need to apply a compression force. Prior to the expansion, that
is, during the start up,
16 the pressure on the paper must be maximized since the inclined surfaces of
the expanded paper
17 are not yet available. A variety of mechanism are available to adjust for
the change in the thick-
18 ness of the paper and the creation of inclined surfaces.
19 In the embodiment of Figure 15, the dual expansion rollers 1502 and 1504
are illustrated.
The dual expansion rollers 1502 and 1504 are provided with a pair of rigid
gripping wheels 1506,
21 1510 and 1508, 1512, respectively. The rigid wheels 1506, 1510, 1508 and
1512 are somewhat
22 greater in diamcter than the expansion rollers 1502 and 1504 and serve to
grip the paper and draw
23 it through. In the case of paper which expands to a thickness of one
quarter of an inch, the dif-
24 ference betwecn the diameter of rollers 1502 and 1504 and the wheels 1506,
1510 and 1508, 1512
must be greater than one quarter inch in order to avoid crushing the expanded
paper. The use of
26 small rigid wheels 1506, 1510 and 1508, 1512 to carry the paper limits the
amount of expanded
27 material which is contacted and therefore crushed. The wheels 1506, 1510,
1508 and 1512 can be
28
WO 95/07225 2168979 PCTIUS94/10209
17
i formed of rubber or any of the materials disclsoed for use with the expander
rolls. The width of
2 the wheels 1506, 1510 and 1508, 1512 is as small as feasible to limit the
amount of expanded paper
3 which is crushed. The wheels 1506, 1510 and 1508, 1512 leave an elongated
path or region of
4 crushed cells along the length of the paper. Preferably, the wheels are
about one half inch wide.
Wider wheels provide greater gripping power but crush a greater amount of
expanded cells. The
6 amount of material crushed is equal to the width of the wheels times the
number of wheels. The
7 number of wheels is not narrowly critical but, the use of too few wheels
will produce uneven
8 drawing of the sheet material. At least two wheels are required, but three
wheels evenly spaced
9 along the draw rollers produced more consistent and even drawing of the
paper. Since the wheels
must be in opposed pairs, too narrow a width produces a risk that the opposed
wheels will be out
11 of alignment and fail to provide a gripping force. The minimum width of the
wheels is controlled
12 by the ability to keep the wheels in proper gripping alignment. The maximum
width of the wheels
13 is limited by need to minimized crushing of the expanded material. In the
instance of a 20 inch
14 wide paper, the use of four half inch wheels, crushes 10 percent of the
paper. The combined
width of the rollers multiplied by the number of rollers, must be less than
20% of the width of the
16 expanded paper, and preferably should be less than 10% of the expanded
width. Most preferably,
17 the combined width is no more than 5% of the expanded paper width.
18 In the embodiment of Figures 16 and 17, the Velcro type hook filament
material 1606,
19 1608 and 1610, 1612, respectively, is spirally wound around the draw
rollers 1602 and 1604, il-
lustrating two of the possible patterns. Once expanded the hook filaments 1606
and 1608 have a
21 great drawing power and is not necessary to have the entire roll covered.
In fact, using less than
22 full coverage can be advantageous. Where the hook filament material 1606 an
1608 is spirally
23 wound around cach draw roll, contact with the expanded material is
continuous, but the expanded
24 sheet material is compressed between opposed hook matcrial intermittently
and only over a limited
region. In this manner the paper is compressed during the start up of the
expansion cycle, and
26 once expanded the paper is drawn primarily on one surface unopposed by
material. Thus, crush-
27 ing of expanded paper is minimized.
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WO 95/07225 PCT/US94/10209
18
1 In the embodiment of Figure 16, the spiral of the hook filament material
1606 on the first
2 roller 1602 is opposite from the spiral direction of the filament material
1608 on the second roller
3 1604. In this manner the hook filament material of the first draw roller
1602 is always opposed
4 by the corresponding material of the second draw roller 1604. Preferably, as
shown in Figure 17,
the filament material spirals 1610 and 1612 are in the same direction. In this
manner, the two
6 spirals 1610 and 1612 are only in opposition, or contact, periodically. In
this manner, the paper is
7 compressed betwcen opposing spirals, as required to start the expansion
process. Once expanded
8 contact between the spirals 1610 and 1612 and the expanded paper is
predominantly one side unop-
9 posed, thereby minimizing the problem of crushing of the expanded cells,
while providing periodic
high compression needed for the startup of the expansion cycle.
11 If preferred, the draw rollers can be provided with a solenoid or a pair of
solenoids, one at
12 each end. The solenoid is provided with a timer which raises the top roller
slightly once the expan-
13 sion is achieved, so that maximum start up compression is available to
initiate the expansion, but
14 minimal compression occurs after the expansion has been achieved so as to
avoid crushing of the
expanded cells. This is possible, because of the interaction between the hooks
and the inclines of
16 the expanded material. The hooks grab the paper and it is not necessary to
force the paper against
17 the hooks by means of an opposing roller. Light contact between the hooks
and the expanded
18 material is stif[icicnt to draw the sheet of expanded paper and maintain
the expansion operation.
19 Once the rotation of the rollers has ceased, the solenoid releases the top
roller to come in contact
with the bottom roller.
21 The rotarv die cutting of the expanded paper is preferably performed using
a hardened
22 steel die with tolerances of .001 of an inch. The anvil is a round,
extremely hard cylinder. It has
23 been found that the ctitting of the plurality of slits results in a
vibration of the rotary die cutter
24 and a shortening of the life of the equipment, in particular, the die. The
vibration problem can,
however, be eliminated by offsetting the knives about 1.5o from the axis of
the die. It appears
26 that the vibration is due to the fact that the rows of knives are spaced
1/8 inch apart. Even
27 though the cutting action is on a sheet of paper only .007 or .008 inch
thick, the net effect is a
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WO 95/07225 2168979 PCTIUS94/10209
19
1 chopping action and a resultant vibration. The skewing of the knives results
in a continuous cut-
2 ting action, siiice there is a simultaneous entry of a plurality of knives
into the paper and
3 withdrawing from the paper. The range is limited at one extreme by the
necessity for the slits to
4 be close to being perpendicular to the edges of the web, so that during the
expansion step, the ex-
pansion proceeds in a controlled manner. That is, the paper expanded without
skewing in one
6 direction. At the other extreme, the skewing of the knives must be
sufficient to provide a con-
7 tinuous cutting and prevent die vibration. Accordingly, the skewing of the
knives, as illustrated
8 in Figure 19, mttst be at least about 0.5 but less than 5 degrees.
Optimally, the range is within 1.0
9 degrees and 1.75 degrees. When the paper is fed from two rolls to an
expander, by reversing the
angular offset of the rolls, the line of the cells formed from the slits, are
offset by an angle which
11 is double the offset produced by the skewing of the knives, rather than
being parallel. This serves
12 to optimize the nesting effect and maximize the cushioning effect.
13 The extenciihle sheet material can be a single layer of flexible paper
material or multiple
14 layers wound on the same roll. Preferably, the multiplies plies are formed
in-situ by using mul-
tiple rolls of single layer sheet material which are combined in the guide
roll path. The advantage
16 of using, for example, two rolls of single layer sheet material is that
where a small amount of
17 material is required to wrap an object, a single roll can be used in the
system. In applications
18 where large amounts of void flll are required, two rolls can be unwound
simultaneously, to
19 produce a two-ply void till material.
Where a Plurality of plies of sheet material are used, either through the
preferred use of
21 two rolls or by using a multi-ply roll, the parallel rows of individual
slits preferably form an
22 angle with the longittidincal axis (the opposing edges of the sheet) in the
range from about 89.5 to
23 87 degrees. Consequently, the parallel rows of slits of adjacent layers
form an angle in the range
24 from about 10 to about 60 with each other. That is, the line of slits of
adjacent plies cross each
other at an angle in the range from about 1 to about 60.
26 Thus, the skewing of the knives not only improves the cutting operation but
also optimizes
27 the cushioning affect.
28
CA 02168979 2005-05-24
WO 95/07225 PCT/US94110209
1 The rotary die cutting equipment includes a paper supply roll 8100 and web
tension guide,
2 indicated generally as 8102, as shown in Figure 18. The web guide controls
tracking of paper
3 from side to side, thereby facilitating high speed die cutting. 'rhe roller
8101 serves to decurl the
4 rolled paper, prior to die cutting. The paper 8104 is fed between between
nip rollers 8106, to the
5 die cutting station indicated generally as 8108. The rotary die 8110,
containing the knives 8111,
6 shown in Figurc 19, interacts with the hard anvil 8112 to produced the
desired slit pattern. The
7 rotary die is driven by a conventional power source, not shown, and can be
belt driven or driven
8 through gear teeth. The slit paper is then wound on a rewind roller 8114.
Nip rollers can be used
9 between the rotary die cutting and the rewind roller 8114.
10 The web tension must be less than 4.5 oz. per inch of width. For paper webs
less than 20
11 inches in width, the problem of maintaining the rewind tension within the
necessary limits is par-
12 ticularly severe. This problem is discussed in United States Patent
5,538,778 of the
13 present applicants. The regulation of the rewind tension can be achieved
through the
14 use of a variahlc tcnsicsn sensor and control 8120. The variable tension
sensor and control senses
15 the amount of paper which has been rewound on the rewind roller 8114.
Preferably, the speed of
16 the paper web throu,h the rotary die 8110 is essentially constant. As the
amount of paper on the
17 rewind rollcr 9114 increa'ec along with the diameter of the rewound web,
the linear speed of the
18 web increases. To maintain a constant tension, the rotational speed of the
rewind roller 8114 must
19 be decreased.
20 A highly sensitive plasma magnetic clutch or a hydraulic clutch can be used
to maintain
21 the rewind tension within the required limits, relative to the width of the
paper web. When the
22 rewind tension exceecls the proper limit, the cells open, and the paper is
wound in the form of
23 open cells. If the rcxvind tension is too low, the paper web is traveling
at an uneconomically slow
24 rate. Further, at low tension the roll is not tight. A tightly wound roll
provides the optimum
amount of material relative to the diameter of the roll. An open cell roll
represents one extreme,
26 while a tightly wound roll represents the other extreme. A loosely wound
unexpanded roll is
27 preferable to a tightly wound expanded roll. In order to amortize the cost
of the equipment over a
28
WO 95/07225 ~=+ ~ ~ '~ ~ ~ ~ PCTIUS94/10209
~
21
1 reasonable period of time, the paper through put must be maintained at the
maximum possible
2 speed. When the tension is unnecessarily low, the rewind mechanism becomes
the bottle neck in
3 the manufacturing operation.
4 The use of a rewind turret mechanism such as disclosed in British patent
777,576 Published
June 26, 1957, U.S. Patent No. 1,739,381 and 2,149,832, provides for a
continuous operation, in that
6 the system need not be stopped when the rewind roll has the desired footage
of material,
7 preferably about 30 pounds of paper per roll.
8 It is to be understood that the filling material sheets of the present
invention may be
9 formed of any desirable and suitable dimensions depending upon the hollow
spaces to be filled in
packaging materials. While the description of the filling material sheet
member of the present in-
11 vention describes one example with respect to size and thickness, this is
not intended to limit the
12 scope of the invention. Where the slit pattern and paper characteristics
have interacted to form a
13 hexagonal cell, the slit paper has sufficient resistance to expansion, to
permit the sheet material in
14 roll form, to be rewound without expansion. This is not the case for slit
pattern/material charac-
teristic combinations which fail to produce the hexagonal pattern. Where the
legs of the cells are
16 insufficiently rigid to form the hexagonal shape, the cells are also
excessively easy to open. In
17 such cases, the sheets have to have the slit patterns cut on a flat press,
for the sheets to be shipped
18 unexpanded, since the conventional rewind rolling action would expand the
slit sheets.
19 Since other modifications and changes varied to fit particular operating
requirements and
environments will be apparent to those skilled in the art, the invention is
not considered limited to
21 the example chosen for the purposes of disclosure, and covers all changes
and modifications which
22 do not constitute departures from the true spirit and scope of this
invention.
23
24
26
27
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