Note: Descriptions are shown in the official language in which they were submitted.
2165902
COMPOSITE HOLLOW MOULDED PANELS AND METHODS OF MANUFACTURE
Field of the Invention
This invention relates to composite hollow moulded panels and their elt~m~ontc, and the methods
of m~nllfa- tllring and combining said elements into said composite panels.
Brief Description of the Prior Art
Composite hollow panels are already known and in common use, such as the famili~r co~ hler
board comprised of a diaphragm of corrugated ~ap.lLoald glued between two flat sheets of
paperboard to form the strong but lightweight wall of a folding container, and a structural panel,
used in Australia. made up from a diaphragm comprised of a continuous layer made from a
multiplicity of moulded pulp egg trays (30 egg type) glued between two panels of plywood or
pulpboard. The recent development of a hollow panel comprised of two ribbed elernPntc is
described in U.S. Patent Number 4,702,870, and an earlier development of a hollow panel,
comprised of a single element formed by means of a multiplicity of moulding dies used in
combination is described in U.S. Patent Number 3,053,728 awarded to Emery in 1962.
The deeply ribbed hollow panel of U.S. Patent Number 3,053,728 was coln~lised of a plurality
of tubular preforms pressed together while still supported on the forming moulds and still
immersed in the slurry of cement asbestos moulding ll~al~lials. But the succescful development
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project was abandoned when the dangers of wolhing with asbestos became known.
The concept of a deeply ribbed composite hollow moulded pulp panel described in U.S. Patent
Number 4,702,870 provides for a ,..~ h;ng network of deep ribs p~ojee~ g from one face of
each of the two co-extensive moulded pulp elements of which it is colllplised, said e1PmPntC
being glued together internally of said hollow panel along the facing outer edges of said
m~ hing rib networks. The co,l~ c,.;ial success of this eol,cept awaits the discove~y and
development of a practical and economical method of m~nnfa~tllre.
Back~round of the ~nvention
In a radically dirfelellt concept to the earlier inventions described above, it is the object of this
invention to create a series of composite hollow moulded panels mo~ Pd from fibrous pulps
such as wood pulps which will allow the ~cccc~rul use of lower grade molllrling materials, such
as waste papers or paper mill slud_e, becd.lse of the greater ~ lh which can be achieved in
the design of said panels and their elemPntc. Instead of the deep thin ribs of the previous
inventions described above, the special advantages of this invention lie in the greater slle~ll
and improved gluing surfaces inherent in the design of at least one extt~ l elem~nt of said
panel, moulded with a plurality of wide ~hirk~Pd areas pr~je-;ling from one face of said at least
one element, to provide an increased total combined area of ,~i~ol~e,l~ l over the entire extent
of said element, and a plurality of wide and secure gluing faces to bind said external elemlont
together with the immP~ tely ~dj~renr elem~nt of said panel.
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It is well known in the industry that the wall thickness conveniently produced at high speed in
a moulded fibre product such as an egg tray is limited by the character of the raw materials
used. Thus the limit for the typical short fibres found in the sludge from paper mills, in which
the fibres are sometimes mixed with clay particles, may be a sheet or wall thi~n~ss in the order
of three millim~res or less, while a sheet of 10 or 15 millimetres in thickness or even more will
be available in products made from the longer fibres found in pulps made from other recycled
products such as old corrugated containers. When consolidated following the preform stage by
hot press drying between heated pressing dies, the final thickness may be reduced to one half
these thickn.ocses or even less. This invention supplies the means to produce thickened areas in
such elements beyond the limits of thi~kn~ss which can be produced in a simple sheet of a
particular pulp type when produced by high speed pulping methods.
The practical success of this invention is ensured by the use of known and widely used wet
vacuum moulding and hot press drying methods, supplemented by the use of a unique method
of producing thickened reinforcing areas at one face of a panel element. The use of a new
method of hot press drying a wet preform at considerably higher speeds, as described in U.S.
Patent Number 5,174,863, will add to the commercial practicality and area of application of this
invention.
Summary of the Invention
A novel method of producing a thickened reinforcing portion in limited areas of one or more
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elements of such a sheet or wall of a moulded panel is made co~ ially practical by the
employment of a series of releasable mounted and freely transferable and rotatable groups of
transfer or pressing dies such as described in said U.S. Patent 5,174,863, by means of which
a plurality of ribs or conical projections, or a series of such ribs or conical projections vertically
imposed, one upon the other, have first been formed in a wet pl~follll. Said ribs or conical
projections may be collapsed and densified in one or a series of wet pressing stages under
vacuum, using carefully designed wet pressing dies to define and control the shape and volume
to which the collapsed material is reduced at each of these interm~di~te wet pressing stages, in
order to control the thicknto5~ location, shape, and lateral tlimpn~ions of the thickened reinforced
area produced in the final hot press drying stage of the process, at the same time creating a
continuously planar surface of at least 80% ullirO~ density, or such greater uniformity of
density as may be required for a printing surface on the opposite side of the sheet or wall, where
a soft or depressed area may have existed in the wet preform as first moulded. The use of
multiple pressing stages to achieve a desired final moulded shape by the hot press drying process
after first using intermediate pressing stages, was exemplified in the m~nllfartnre of moulded
fibre shell cases on special moulding m~ in~ry design~l1 and supplied by Emery to the
Brunswick Corporation for the U.S. Air Force, as recounted but not described for military
secrecy reasons, in the article "A Small C~n~ n company has opened the door on a new
technology" by Suzanne Marr, published in the C~n~ n Con~--ltin~ F.nginPer, June, 1974. The
usual shape of ribs or conical elements projecting from a moulded fibre sheet or wall is shown
in the drawings of U.S. l)esign Patent DES229,608 issued to Reifer, December, 1973.
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The thickness, shape, area and spacing of the thickened portions of the moulded elements formed
in this manner will be determined by the requirements and structural design of the composite
panel of which it forms a part, at the same time regulating the span of the surrounding
unreinforced unthickened rem~ining area of the sheet or wall of the moulded element on which
they are formed. Such an element may also be designed and m~mlf~rtnred for use as an
uncombined single sheet or wall of a moulded product.
Brief Description of the Drawin~s
In drawings which illustrate example embodiments of panels and panel elements constructed in
accordance with this invention;
Figure 1 is a cross sectional view of a portion of a panel element shown in both a wet preform
state and final pressed and dried state;
Figure 2A is a cross sectional view of a portion of another panel element in a wet preform state;
Figure 2B is a cross sectional view of a portion of the panel element of Figure 2A shown both
in a wet preform state and final pressed and dried state;
Figure 3 is a cross sectional view through a portion of a composite panel;
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Figure 4 is a cross sectional view through a portion of another composite panel;
Figure 5A is a cross sectional view through a portion of a primary panel element in a wet
preform state, with three supplementary wet preforms superimposed thereon;
Figure 5B is a cross sectional view through a portion of the panel elements of Figure SA, shown
in an intermediate pressed state;
Figure SC is a cross sectional view of a portion of a panel element in its final state, formed from
the wet preforms shown in Figures SA and 5B;
Figure 6 is a cross sectional view through a portion of another composite panel, formed by
combining two of the final elements shown in Figure 5C.
Figure 7 is a cross sectional view through a portion of yet another composite panel formed by
combining one each of the finished elements shown in Figure 1 and Figure 5C;
Figure 8 is a cross sectional view through a portion of another panel element shown in the
traditional egg tray form, shown in both an initial wet preform state and a final state;
Figure 9 is a cross sectional view through a portion of a panel formed from two of the panel
elements 31 of Figure 2B and one of the panel element 40X of Figure 8;
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Figure 10 is a plan view of another panel suitable for use as an acoustic ceiling panel;
Figure llA is an edge view of the panel of Figure 10;
Figure llB is an enlarged edge view of a portion of the panel shown in Figure 11A;
Figure 12 is a plan view of a panel adapted to be folded into a container;
Figure 13 is a cross sectional view of a portion of the panel of Figure 12 along A - A;
Figure 14 is a cross sectional view of a portion of the panel of Figure 12 along B - B;
Figure 15 is a cross sectional view similar to that of Figure 14, folded at 90~;
Figure 16 is a diagram showing the general form of a pulp moulding m~rhinP with hot press
drying equipment which can be used to m~mlfa~ture the moulded panel element of Figure 2B.
Figure 17 is plan view of a portion of one side of a moulded element showing one of the variety
of arrangements of thickened areas available.
Figure 18 is a plan of a portion of one side of a moulded element showing another one of the
variety of arrangements of thickened areas available.
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Figure 19 is a plan view of a portion of one side of a moulded elem~t showing a third one of
the variety of arrangements of thick~Pd areas available.
Figure 20 is a plan view of the planar side of a single sheet with thi~on~d rc;hlfolced areas,
adapted to be folded into a container.
Figure 21 is a cross sectional view of sheet 401 along A - A.
Figure 22 is a cross sectional view of the sheet 401 along B - B.
Figure 23 is a cross sectional view of the sheet 401 along either A - A or B - B, folded at
900 .,
Detailed Description of ~lef~ ,d Embo-lim~ontc
- In the drawings, Figure 1 is a cross section through a portion of a wet moulded pl-fo
30, showing the outlines 10 and 11 of said preform 30, and the outlines 12 and 11 of a
final form 30X into which it can be cG~ ,;,sed, for example, into one half its original
thi~kn~ss~ by using a mating hot press forming die with a moulding face in the shape of
line 12, in any form of the well known hot press drying and finiching system.
- Figure 2A is a cross section through a portion of the wet pl~foll-l 30 of Figure 1, but
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with the surface along line 11 directed upwards, ready to present the smaller ribs or
conical projections to the final hot press die with a moulding face in the shape of line 13
of Figure 2B;
- Figure 2B is a cross section of the portion of the wet preform 30 shown in Figure 2A,
showing the final shape and reduced volume of the finichP~ element 31 into which said
wet preform 30 may be transformed, by transfer into a pair of hot press drying dies, the
first of said dies having a planar moulding face to produce the planar surface shown in
profile along line 15, and the second of said dies having a moulding face as shown in
profile along line 13, and in this example as shown, the volume of wet preform material
included in and under each of said ribs or conical projections is designed to be
compressed and densified to approximately one half the net vclume contained in said rib
or conical projection and the material immPdi~tely thereunder from which it was formed,
with the rem~ining unthickened portions of said wall of said fini.chP~ element 31 being
compressed to one half the wall thi~knpss and volume of the related portions of said wet
preform, thus assuring an approximately uniform density throughout the entirety of said
finichPd element 31.
- Figure 3 is a cross section through a portion of a composite hollow moulded panel 33,
comprised of one element 30X and one element 31 glued together between the prominent
surfaces of said ribs or conical projections along line 11 of said element 31, thus
providing one uninterrupted planar outer surface and one ribbed or indented opposite
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surface to said panel 33.
Figure 4 is a cross section through a portion of a composite hollow moulded panel 34,
comprised of two elements 31, glued together at the mating prominent surfaces of their
respective mating thickened areas along the lines 13 of each of said elements, thus
providing uninterrupted planar surfaces on the two outer faces of said panel 34, along
the lines 15 of said elements.
Figure SA is a cross section through a portion of a wet prefo~ 35 showing additional
wet preforms 36 superimposed upon the upwardly directed ribs or conical projections
along line 20 of said preform 35 in a l~min~ting process.
Figure 5B is a cross section showing the wet preforms 35 and 36 in their interm~ te
wet pressed forms 35X and 36X as in-lic~ted in profile along lines 17 and 18, said
interrnediate pressing operation having been made between a pair of intermP(li~te wet
pressing dies, with the first of said dies having a moulding surface to retain the shape of
one surface of said element 35X along line 19, and the second of said dies having
moulding surfaces conforming to lines 17 on partly colll~lcssed preforms 36X and
ret~ining the existing planar form of the rem~ining areas along line 20 of the preform
35X, thus tending to reduce the sideward spread of the upwardly directed projections
now partly densified as intlic~t~cl in profile along lines 18.
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- Figure SC is a cross section of a portion of element 37 in the final finished form and
reduced volume into which it can be compressed from the partially compressed wet
preforms 35X and 36X by transfer into a pair of hot press drying dies, the first of said
dies having an unill~ellu~Led planar surface to form the planar surface in-lic~ted in profile
along line 24, and the second of said dies having a moulding surface ap~lopliate for
forming the final shape of the other surface of said element 37, as in-licate~l in profile
along line 25, the net combined volumes of one of said elemPnt~ 36, one of the upwardly
directed projections along line 20 of said preform 35, and the material directly thereunder
being compressed along line 20 to approximately one half of said volume in the related
thickened area long line 25 of fini~h~cl element 37, and the rem~ining planar areas of said
preform 35 along line 20 being compressed to one half their thi~l~n~s~ and volume
between lines 25 and 24 of said finished element 37.
- Figure 6 is a cross section of a portion of a composite hollow moulded panel 38,
comprised of two of the fini~hecl elements 37 of Figure SC, glued together at the mating
prominent surfaces of their respective thickened areas along the lines 25 of each of said
elements 37, thus providing uninterrupted planar surfaces on each of the two outer faces
of said panel 38, as shown in profile along lines 24 of said elements 37.
- Figure 7 is a cross section of a composite hollow moulded panel 39, comprised of one
element 30 of Figure 1 and one element 37 of Figure SC, glued together at the ribs or
conical projections along line 11 of said element 30, and the mating prominent surfaces
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of the thickened areas along line 25 of element 37, thus providing one uninterrupted
planar surface on one outer face of said panel 39 along line 24 of said element 37.
- Figure 8 is a cross section of a portion of a wet preform 40 of the traditional egg tray
shape, having projections above side 21 and projections below side 23, showing the final
shape and reduced thicknPss as defined by lines 22 and 23 of the fini~h~d element 40X
into which said preform 40 may be compressed and densified by the well known hot
press drying process.
- Figure 9 is a cross section of a portion of a composite hollow moulded panel 41,
comprised of one element 40 of Figure 8 serving as a diaphragm7 and two elements 31
of Figure 23 serving as the outer elements of said panel 41, the flrst of said elements 31
being glued along the projecting thieken~d areas of line 13 to the projecting surfaces
along line 22 of said element 40, and the second of said elen e~ts 31 being glued along
the projecting thickened areas of line 13 to the projecting surfaces along line 23 of said
element 40, thus creating a panel with an unin~ellu~ted planar surface at each outer face.
- Figure 10 is a plan view of a composite hollow moulded panel 100, suitable for use as
an acoustic ceiling panel or a drawer bottom comprised of two moulded elements glued
together, with a reguiar pattern of indentions 49 on one face, as shown.
- Figure 11A is an edge view of said panel 100 showing the internal construction formed
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by the two moulded elements of which it is comprised, element 30X of Figure 1, and
~ element 31 of Figure 2, said indentations 49 of said element 30X being formed as the
reverse side of the conical projections, instead of the optional alternative ribs.
- Figure 11B is a cross section through a portion of the panel 100 taken at line AA,
showing said indentations 49 formed along line 12 of said element 30X, and the related
conical projections along side 11 of said element 30X glued to the prominent surfaces
along line 14 of the mating thickened areas of said element 31.
- Figure 12 is a plan view of a composite hollow moulded panel 101, similar to panel type
34 of Figure 4, with the two elements 31 moulded complete with the cutouts 52 and fold
lines 51 required to form a folding container when said two- elements 31 are glued
together at the matching elongated prominences formed by the thickened areas on the
inwardly directed faces of each of said elements 31. In use, a first end wall 56 is
hingedly connPcte(l at two parallel edges and fold lines 51 to the adjacent first edge of
a first side wall 55, and at the adjacent first edge of a second side wall 55, and a second
end wall 56 is hingedly connected at a first edge and a fold line 51 to a second edge of
said first side wall 55, and at a second edge and fold line 51 is hingedly connPct~d to a
flap 58, which may be stapled or glued to the free end of the second of said second side
wall 55 thereby to form the complete perimeter of said container, which is then closed
by first folding in the four top and bottom walls 57, which are hingedly connected to the
upper and lower edges of said end walls 56, at fold lines 50, and then folding in the four
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top and bottom walls 54, which in turn are hingedly connected at their edges to the upper
--~~ and lower edges of said side walls 55, at fold lines 53.
- Figure 13 is a cross section through a portion of a side wall 55 and of an end wall 56 of
said panel 101 of Figure 12, along AA, showing the thickened areas of the two elements
31 glued together at the glue lines 59, and details at the fold line 51.
- Figure 14 is a cross section through a portion of a side wall 55 and a top wall 54 of said
panel 101 of Figure 12, along BB, showing the glue line between two elongated
thickened areas of said elements 31, and details of the fold line 50.
- Figure 15 is a cross section through a portion of a side wall SS and a top wall 54 of said
panel 101 showing details at fold line 53 when said panel is folded there at an angle of
90~ between said side wall 55 and said top wall 54.
- Figure 16 is a diagram showing an example of a general arrangement of the locations for
the moulding, transfer and pressing dies, and of the rotors by means of which said dies
and the moulded items which they contain are transported in order to wet mould,
collapse, densify and press dry the preform 30 of Figure 2A into the fini.ch~l element 31
of Figure 2B. As shown in the diagram the wet forming dies 251 are transported on
rotor 201 through the wet moulding process, and the wet preforms are transferred to the
transfer dies 252, and from there transported on rotor 202 to be transferred to the flat
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faced pressing dies 253 releasably mounted on rotor 203. Said flat faced pressing dies,
still cont~ining the unchanged wet preforms, are then transferred by rotor 204 from said
rotor 203 to rotor 205, where said flat faced dies 253, still cont~ining the unchanged wet
preforms, are locked into mated pressing position with heated pressing dies 254 which
conform in shape to the outline 13 of the element 31 of Figure 2A. The heated pressing
dies 254 are then pressed against the wet preform 30 and towards the flat faced die 253,
thus collapsing the wet moulded material projecting from side 11 of said element 30 and
condensing the total material of said wet preform 30 into the final form of said fini~hPcl
element 31.
After the final product has rem~in~l between said pressing dies 253 and 254 for the required
drying time, the said flat faced pressing dies 253 are unlocked and transferred from the mating
position with said heated pressing dies 254 on rotor 206 and thence to rotor 203, from whence
said fini~h~(l products 31 are discharged from said flat faced pressing dies 253 and said empty
dies 253 are then rotated on said rotor 203 to transfer position with said transfer dies 252 on
rotor 202, to receive a new supply of said wet moulded preforms 30.
- Figure 17 is a plan view of a portion of one face of the moulded external element 31 of
the panel 100 of Figure 10, with a plurality of isolated but regularly shaped promin~nres
214, and intervening nnthirkrn~ areas 215 on the inwardly directed face thereof, in one
of the variety of arrangements available for use with said panel 100.
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- Figure 18 is a plan view of a portion of one face of a moulded external element 51 of
~ the panel 101 of Figure 12, with a plurality of closely spaced parallel and elongated
prominences 315 thereon, intel-upt~d by a narrow unthiekenPIl area at the fold line 353,
conn~cted together at larger intervals with transverse plo~ np~ es 314, and with
intervening unthickened spaces 316 on the inwardly directed face thereof, in one of the
variety of arrangements available for use with said panel 101
- Figure 19 is a plan view of a portion of a moulded sheet or element 431, which sheet
may be used as an alternative to the moulded element 31 of panel 101 of Figure 12, or
as the single moulded sheet 431 of the panel 401 of Figure 20. Said sheet or element
has on one face thereof a network of prominences 414 and intervening unthickened areas
416, said network being interrupted by a continuous elongated ~Inthiekened area at each
fold line such as shown at fold line 453, said network providing stability in both vertical
and horizontal directions in the side wall or end wall of a container.
- Figure 20 is a plan view of the continuously planar surface of one face of the moulded
sheet 431 of the folding container panel 401, said sheet 431 having a net work of
reinforcing prominences on its other face, similar to that shown in Figure 19. Said sheet
431 of said container panel 401 who has been moulded complete with the required
perimeter cutouts 452, and fold lines 450, 451 and 453 required to form a container. In
use, a first end wall 456 is hingedly conn.octed at two parallel edges and two fold lines
451 to the adjacent first edge of a first side wall 455 and the adjacent first edge of a
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second side wall 455, and a second end wall 456 is hingedly comle~ted at a first edge and
a fold line 451 to a second edge of said first side wall 455, and at a second edge and fold
line 451 is conn~oct~d to the adj~cerlt edge of a flap 438, which may be glued or stapled
to the free end of said second side wall 455, lhe.eb~ to form the complete folded
perimeter of said container, which is then closed by first folding in the four top and
bottom walls 457 which are hingedly conn~cted to the upper and lower edges of said end
walls 456 at fold lines 450, and then folding in the four top and bottom walls 454,
which are hingedly conn.qcted to said side walls 455 at their top and bottom edges and
at fold lines 453.
- Figure 21 is a cross section view along BB of portions of a side wall 455 and an end wall
456 of said sheet 431 of Figure 12, hinge~ly conl-Pc~ together at fold line 451.
- Figure 22 is a cross section view of portions of a side wall 455 and a top wall 454 of
Figure 20 along AA hingedly conn~cte~ together at fold line 453.
- Figure 23 is a cross section view of portions of a side wall 455 and a top wall 454 of
Figure 12 along BB hingedly conn.octetl together and folded at 90~ to each other at fold
line 450, and showing details of the completed fold at said fold line 450.
