Methods and apparatus for making grids from fibers

Method and apparatus to form grids of open cells from fibers, especially wood fibers and fibers from waste paper and mixed waste materials. The invention utilizes a screen carrying a plurality of elastomeric pads of predetermined sizes arranged thereon in predetermined spaced relation to each other. The fiber is deposited between the pads but not above the pads. The deposited fibers and the pads are compressed normal to the screen, which causes the fiber in the spaces between the pads to be consolidated both normal and parallel to the screen, resulting in a open grid having cells of the shape of the pads. Numerous variations are provided including several continuous production embodiments. The invention uses state of the art technology for virtually all aspects.

FIELD OF THE INVENTION 
This invention relates to the production of open cell grids which can be 
used in and on various other structures as components thereof. The 
invention utilizes many conventional and some proprietary techniques for 
the manufacture of structural components from fiber. 
BACKGROUND OF THE INVENTION 
The present invention pertains to the production of open cell grids in a 
highly advantageous and inexpensive manner, and pertains to the use of 
fiber to produce such grids The fibers can be cellulose or other sorts, 
such as various plastics, fiberglass, and the like. An important advantage 
of the invention is to utilize wood and non-wood fiber which is otherwise 
not utilized. 
Trees raised in the United States of America for commercial purposes are of 
two general types, hard and soft. Softwoods are fully utilized for the 
manufacture of paper, newsprint, and other paper products. The large, good 
quality, hardwood trees are well utilized to produce lumber. 
However, there are also hardwood trees which are relatively small, somewhat 
deformed, or not well suited for the production of lumber for various 
other reasons. Further, the smaller limbs of trees are not utilizable for 
lumber The present invention, so far as it utilizes wood fiber, is an 
advantageous way of utilizing this forest fiber resource which is 
otherwise wasted, or, at best, under utilized. 
The invention can be accommodated to use with plastic fibers, such as 
polyethylene and polypropylene, as well as fiberglass, and more "exotic" 
man-made fibers, such as aramid. These additional fibers, depending upon 
the end use, will add strength, water resistance, and other desirable 
characteristics to the final open cell grids produced in accordance with 
the invention. 
The invention has another important advantage in that it can utilize, in 
addition to low-grade trees, limbs and the like, as discussed above, waste 
fibers of all sorts. There is a tremendous problem in the world today of 
having to deal with disposition of waste material. Land fills are becoming 
filled, and the burden on the prime natural resources is increasing. By 
recycling waste materials, the pressure on the landfills, the air 
pollution, and the like are reduced, and at the same time trees are saved, 
thus well husbanding our forest resources. 
The invention can work with waste paper of all sorts, including computer 
paper, magazines, newsprint, boxes, and the like, and it can even work 
with mixed fibers including both such cellulosic and non-cellulosic 
(man-made) fibers. This in and of itself is an important advantage, 
because waste paper from offices and residential communities contain many 
contaminants such as clay, ink, plastics, staples, and the like. This 
mixed waste paper, etc. can be used without prepatory processing such as 
deinking, bleaching, or the like, and with minimal prepatory processing, 
such as screening to remove some of the larger contaminants, to form a 
structural product in accordance with the invention. This so particularly 
if the grid is to be incorporated into the interior of another structural 
item, e.g. a door. This is very important with respect to recycling in 
that such mixed waste paper and waste materials, an unwanted and 
under-utilized fiber resource, can be used. Thus, the invention has the 
important advantage of the ability to recycle and incorporate all sorts of 
wood fiber, nonwood fiber, and nonwood waste without the added expense of 
separation of these materials to produce new lightweight but strong 
structural products and components of such products. 
This invention utilizes some of the technology of U.S. Pat. No. 4,702,870 
by the present inventor together with another. That patent is owned in 
common with the present invention. 
The present invention produces grids of a monolithic one-piece character. 
The grids are formed in accordance with the invention either in final form 
or in near final form and therefore do not require any additional assembly 
and/or attendant handling The common prior art method of making somewhat 
similar structural honeycomb material begins from flat sheets or strips of 
paper or paper-like material which are glued at spaced points, pressed, 
and then expanded to produce a grid of diamond-like open cells. The 
present invention is substantially different from and is thought to be a 
substantial improvement over that prior art, in that no gluing at spaced 
points and no expanding processes are required. The present invention also 
provides a step forward in the art in that very complex structures (See 
FIG. 2E for example) can be produced. It is impossible to produce such 
complex structures with prior art methods because only uniformity of the 
cells throughout such prior art structures is possible. 
The present invention also is to be distinguished from various kinds of 
other fiberboard and paper making devices and methods. An important 
characteristic of the invention is the use of a mold element which deforms 
during the molding process in order to compress the fibrous material in 
directions perpendicular to the direction of pressing, as well as parallel 
to the direction of pressing. This is not found in many other such 
techniques, including the manufacture of egg cartons, corrugated 
cardboard, and the like. 
Several forms of the invention produce material continuously This is a 
substantial improvement over all of the prior art that is of a batch 
nature. 
SUMMARY AND ADVANTAGES OF THE INVENTION 
Producing articles from fibrous material is a well developed art. The 
present invention has the advantage that it can utilize, depending upon 
the characteristics of the end product required and the particular fibers 
being used, all of this technology. That is, the fibers can be carried in 
air, water, or other fluids, the curing can be done with heat, pressure, 
adhesives, and the like, and drying can be accomplished utilizing many 
different machines and approaches to drying or otherwise finishing the 
formed product. This ability to use a great deal of the state of the art 
is an important advantage of the invention, i.e., proven technology and 
machinery can be used to produce better products in accordance with the 
invention. 
Further, the invention lends itself to implementation as either a batch 
process or a continuous process, again depending upon the particular 
parameters of the particular application and the particular end product to 
be produced. 
The invention, in its simplest form, depends upon technology similar to 
that of prior U.S. Pat. No. 4,702,870. It includes a mold made up of a 
base carrier, screen or filter, having a plurality of elastomeric pads 
attached to the base. These pads are of a predetermined shape and size, 
and are in a predetermined relation to each other on the carrier. The 
manner of selecting the size, shape and spacing of these pads on the 
screen determines the nature of the finished product, as will appear from 
the detailed specification below. The carrier fluid moves through the 
mold, depositing the fibers between the pads only. No fiber is deposited 
on top of the pads. These elastomeric (preferably silicone rubber) pads 
are a key part of the entire process, not only to establish the initial 
shape of the grid, but also to determine its consolidation After the 
fibers are deposited, the grid is consolidated by the application of 
pressure to the tops of the pads. As this pressure is applied, the pads 
compress in the direction of the applying force, but they also expand at 
right angles thereto, thus reducing the spaces between the pads where the 
fiber is located. Thus, the deposited fiber is consolidated both 
vertically and horizontally into an open cell grid. 
After the grid is thus formed, it can be removed and/or cured and somehow 
finished and then used in just that form. Another option within the 
invention is to consolidate the grid a second time with a different set of 
similar pads being inserted into the grid from the opposite side as 
compared to the insertion of the first set of pads. This produces a 
finished product which is stronger, but with grid bars which are shorter 
and smaller than the bars which result from a single consolidation step. 
There is no particular preferred embodiment as to single or double 
consolidation. That is, sometimes it may be desirable to produce a grid in 
a single pass because it is cheaper, it can be done faster, and for one 
particular embodiment, the bars are taller, i.e., the grid is thicker, and 
the reduced strength of the finished product is unimportant. In another 
environment, the double pressing from opposite sides may be desirable and 
the shorter, denser, and stronger grid produced under that particular set 
of conditions is deemed worth the extra effort and expense of the second 
pressing step. 
However, more in general, given the flexibility of the invention as to 
fiber selection (i.e., some fibers are inherently stronger and/or bind 
more tightly than others); pad size, material and spacing; operating 
pressures, and the like, the same options available to double 
consolidation are also available in a single consolidation. However, 
double consolidation results in improved dimensional accuracy, i.e., the 
dimensions of a double consolidated grid, in general, will be closer to 
the ideal or "blueprint" dimensions than will those of a single 
consolidated grid. 
The present invention allows the manufacture of a wide range of products 
displaying a diverse set of properties, e.g. a product having some 
resilience and/or cushioning properties may be attained, due to the wide 
variety of materials used and pressures available for manufacturing, the 
choice of single versus double consolidation, grid sizes, and the like. 
Yet another option of the invention is to press the grid off of the mold 
after it is formed. This produces a grid having grid bars which are 
considerably shorter and thicker. This particular set of characteristics 
and performance parameters may be desirable in any particular environment. 
This is yet another aspect of the versatility of the invention. 
Another advantage of the double pressing form of the invention is that the 
second mold, that is, the elastomeric pads on the second carrier or 
screen, can be designed with closer tolerances so that the final 
consolidated shape of the bars in the grid are closer to exactly what is 
required by the particular user environment. 
Yet another advantage of this second pressing of this two pressing 
variation is that stray fibers which may extend from the grid after the 
first press, are then pushed in and consolidated into the bars, leaving 
the grid quite smooth at both ends In a first press, there are inevitably 
at least a few stray fibers which give a somewhat unsightly appearance. 
This may be unimportant, depending on where the invention is used, i.e., 
the particular demands of the particular environment and end use. For 
example, if the grid is to become the core of a door, stray fibers may not 
matter. 
In the variation of the invention wherein the consolidated grid is pressed 
off of the mold, the apparatus used could include state of the art 
papermaking presses. These machines lend themselves to both continuous and 
batch processes. The result of this variation is a relatively thin, but 
highly consolidated, open cell grid which has an appearance similar to 
that of a flat sheet having holes punched in it. However, the performance 
properties of the product of this form of the invention are completely 
different from a simple sheet with punched holes. These differences are at 
least partially due to the orientation/arrangement of the individual 
fibers; more specifically, in a simple sheet the fibers are generally 
randomly arranged whereas in the invention's product the majority of the 
fibers are aligned following the grid pattern chosen. This generally 
uniform alignment of the fibers in the grids produced in accordance with 
the invention provides relatively greater strength than is possible with a 
random alignment of fibers. 
The major differences between the present invention and that of prior U.S. 
Pat. No. 4,702,870 include that the present invention produces an open 
cell grid and the prior patent is limited to the use of wood fiber. That 
prior patent produces three dimensional structural members made of wood 
fiber having a flat wall with flanges on one side of it. The versatility 
of the open grid of the invention is much greater than that of the product 
of that prior patent. However, the developed technology with which that 
prior invention is implemented is usable, in large measure, in the present 
invention, and that, by itself, is an important advantage of the present 
invention, i.e., use of proven and developed machinery and methods. 
The open grid structures produce in accordance with the invention are quite 
different from and can be used in different applications than the 
structures produced in accordance with the '870 patent. For example, when 
bonding two liners or boards to either side of a core, it is important to 
have balanced construction. With the open grid of the invention, bonding 
two similar liners to either side of the open grid would produce a 
balanced construction. With the '870 product, when the two liners are 
bonded to the two sides of the product produced thereby, the properties on 
the flat side will be considerably different from those on the rib side. 
Further, the open grids produced in accordance with the invention can be 
wrapped around a smaller radius than can the products produced by the '870 
patent. In addition, only the invention could be used if it were desired 
to have the ability to see through the structure produced. The solid wall 
produced by the '870 patent would not have this ability. Yet another 
difference is that if a light weight structure yet a thin strong structure 
using a minimal glue spread were desired, then an open flat grid produced 
in accordance with the present invention would be preferable over the 
product produced by the '870 patent. Another feature is that, when using 
double consolidation from opposite sides of the two structures, with the 
open grid of the invention, the grid bars will be more uniform and there 
will be more complete densification. With the '870 patent, using double 
pressing on the ribs, the same degree of uniformity and densification 
could not be achieved. Finally, the finished product of the invention 
could be used in different environments than could that produced by the 
'870 patent, because the products produced in accordance with the 
invention in general will be stronger, all other things being equal or 
comparable. 
The open cell grids produced by the invention have many applications. They 
can be used to produce furniture, boards of different sorts for walls in 
aircraft and the like, as insulators, and as cushioning members of various 
sorts. Further, it is possible to stack several grids produced by the 
invention, offsetting the bars and cells from one to the next, and joining 
them with thin sheets therebetween. This resultant composite structure 
will be extremely strong as well as lightweight and will have good 
insulating qualities. The cells are thus sealed by the thin sheets to each 
side, and the sheets improve the resistance to bending and twisting of the 
composite structure. That is, an open cell grid of the invention is more 
susceptible to twisting and bending by itself than it is when bonded to 
relatively thin sheets on one or both sides of the grid. 
Another important advantage of the invention is that it utilizes fiber 
derived from the currently under-utilized scrap wood produced by 
commercial lumbering and wood cutting. In addition, the invention can be 
used either with such cellulose fiber alone, with a non-cellulose fiber 
alone, and with combinations of cellulose fiber with some non-cellulose 
fiber. For example, the addition of varying amounts of polyethylene, 
polypropylene, and other plastic materials can impart improved performance 
characteristics to the final product in regard to resisting water, 
improved strength, resistance to shattering, and the like. This 
application of the invention method and apparatus to all sorts of fibers 
is an important advantage of the invention. 
As is clear, production of various products using the open cell grids of 
the invention in place of solid material as the core material, such as in 
some furniture and structural members for example, achieves important 
advantages of reduced weight. Cost may also be reduced, that depends on 
many factors. These advantages are achieved while maintaining sufficient 
strength for the particular product. Advantages for open cell cores also 
include less material consumed, reduced shipping costs, and facilitates 
handling and assembly by the manufacturer, the carriers, and finally, the 
ultimate purchasers. For some applications, the strength-to-weight ratio 
is of extreme importance over maximum strength obtained from a solid core. 
This reduction of weight, with minimal loss of strength through the use of 
open cell structures, has long been known in the aviation area for making 
partitions, structural components, and the like on board aircraft. 
In order to perform the invention method in a continuous manner, it is an 
important advantage that state of the art machinery and techniques can be 
used. That is, various standard machines to lay down the fiber, and to 
form the grid, and later to dry and cure it, are all utilizable, in both 
continuous and batch variations, in order to implement the invention 
Again, this is an important advantage in that proven state of the art 
technology with little modification can be incorporated into the 
invention. 
The invention is extremely versatile in all its facets. It can be used to 
make open cell grids in many different sizes, in discrete or continuous 
pieces, in all sorts of thicknesses, that is, thicknesses of the grid 
overall (which corresponds to the heights of the grid bars) as well as the 
thickness of the bars themselves making up the grid, and of all sorts of 
materials and combinations of materials. The end products are useful for 
many reasons, including containers, panels for home and vehicle 
construction, insulating panels, and all sorts of other applications. 
There is thus provided a method and apparatus in accordance with the 
invention which is well suited to its areas of application, which achieves 
important advantages, and which is thus highly suited to its areas of 
application.

DESCRIPTION OF THE PRIOR ART 
Referring to FIGS. 1A and 1B, there is shown a prior art method of 
producing open cell grids which are superficially similar to those 
produced by the invention. The grid 10 of FIG. 1B is commonly called a 
"honeycomb." These honeycombs are fabricated from flat sheets or strips 12 
or paper or paper-like materials which are combined by means of spaced 
spots of glue 14. The assemblage shown in FIG. 1A is pressed, and then the 
adhesive is allowed time to cure The assemblage is trimmed and then 
expanded into the structure shown in FIG. 1B. 
The present invention provides advantages over this particular prior art, 
namely, the avoidance of glue and the other multiple fabrication steps, 
and the greater flexibility of production of many different sorts of open 
cell grids. The invention differs from this prior art in that properties 
in the length and width directions could be engineered. The prior art 
"honeycomb" material is made of strips 12 of paper like material combined 
by means of spaced spots of glue 14. The strength properties parallel to 
the length of the papers is higher than the properties perpendicular to 
the length (the width direction) as shown in FIG. 1B. In this invention, 
because of the way in which the fibers form between the pads, they will 
predominantly lay along the lengths of the grid bars. Thus, for a square 
pattern the properties will be uniform in the length and width directions. 
A hexagonal pattern will have uniform properties in three directions as 
shown by the arrows in FIGS. 2A and 2C as examples. Complex patterns will 
have their main properties along the directions of the grid bars in the 
pattern. An advantage of this invention is that because the fibers from, 
randomly yet predominantly along the lengths of the grid bars, then the 
grid arrangement or pattern could be engineered for specific length, 
width, or off axis property requirements. 
The invention should also be distinguished from the prior art of corrugated 
fiberboard. Corrugated fiberboard is made from flat fiberboard material. A 
single sheet is corrugated and is made into the middle core, or corrugated 
medium. This requires a separate operation. Adhesive is applied to the 
nodes of either one or both sides of the corrugated middle core, and then 
bonded to one or two flat sheets, respectively. The shape of the core is 
maintained by the bonds. The present invention has important advantages 
over this technology, in that the fibers are formed directly into the 
finished shape in one step. Again, no gluing or adhesive steps are 
required to maintain the shape or for any other reason, except, in certain 
embodiments, to bond the fibers together into the invention's monolithic 
grid. Further, panels produced with grids according to the invention are 
stronger and have different characteristics than do corrugated board. 
The invention should also be distinguished from certain pulp molded 
articles, such as egg cartons, pots for flowers and the like, baskets, 
cushioning ends for fluorescent light tubes, and the like. These products 
are made on rigid molds. The mold is often semi-porous and is covered with 
screening material. A vacuum is pulled at the back of the mold causing 
flow through the screen and the mold so that the fibers form a uniform mat 
over the screen. The mat on this rigid mold is consolidated with a mating 
reverse shaped solid mold pressed against the mat on the forming mold. 
This consolidates the mat between the two mating molds. The direction of 
the consolidation force is perpendicular to the mat. In the present 
invention the consolidation force is both parallel and perpendicular to 
the bars of the grid. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the group of FIGS. 2A-2E, various forms of the grids which 
may be produced in accordance with the teachings of the invention are 
shown. 
In FIG. 2A the grid 16A is of a hexagon open cell structure. In FIG. 2B, 
this grid 16B is made up of rectangles arranged in an overlapping or brick 
wall type of array. In FIG. 2C, the grid 16C is made up of square cells 
arranged squarely with respect to each other. In FIG. 2D, the grid 16D has 
square cells, but they are off set in rows by 1/2 of a cell. FIG. 2E shows 
mixed cell shapes 
In all of these FIGS. 2A-2E, the dotted lines indicate that the grid can 
have an indeterminate length and/or width. 
FIG. 2E shows yet another important facet of the versatility of the 
invention. The invention has the ability to put the fiber, and thus the 
strength, in different parts of the same structural component. Referring 
to FIG. 2E, a grid 16E is shown as being made up of cells of many 
different sizes and with the various size cells in different 
configurations and relationships to each other. Grid 16E includes small 
square cells, large square cells, very large square cells cut in half into 
triangular cells, and small and large rectangular cells. Again, the dotted 
line showing indicates that the shapes and lengths and widths are 
indeterminate in accordance with other teachings of the invention as set 
forth herein. It can be appreciated especially well from FIG. 2E that the 
variations of grids producible in accordance with the invention, are 
substantially without any limit, only the designer's imagination and need 
driven demands define the bounds 
As is clear from these figures, any sort arrangement could be used. The 
cells could have triangular shapes, pentagon shapes, and all sorts of 
geometric and non-geometric other shapes. The variations are literally 
without limit. 
An important advantage of the invention is that it may be used for 
fabrication of various kinds of structural products and nonstructural 
products, structural components of such products, such as core stock for 
doors or lightweight office furniture, such products as used in various 
places in housing construction and in commercial construction, and in any 
other place where lightweight, high strength panels are required 
Nonstructural products and components of such products include cushioning 
sheets and insulation products and similar products as used in various 
places where lightweight, low density structural panels are required. 
FIG. 3 shows a composite such panel. Three of the grids 16A of FIG. 2A are 
shown by way of example. Any of the other grids could be used, and 
combinations and multiple layers of such grids could be used as well. 
Inter-sheets 38 of any suitable material are used to bond the three grids 
16A together. It should be noted that the middle grid 16A has been rotated 
90.degree. with respect to the two outer layers Rotating the middle 
grid(s) at various angles can be used to balance or otherwise engineer the 
properties in the length and width directions of the panel or to enhance 
specific properties along a specific direction(s). 
Other advantages of a multi-grid construction such as that shown in FIG. 3 
is that the insulation quality is tremendously enhanced, one or more of 
the grids can be used to still further enhance both sound and thermal 
insulation by filling the cells thereof with suitable material. Also, fire 
retardant materials can be used to fill the cells to achieve that 
important advantage in the composite structure, and other advantages can 
also be achieved. This optional filling of the cells is shown in FIG. 3. 
It is also possible to so fill the cells of all of the grids, where the 
panel is closed, as in a door, for example. Also, the grids could be 
bonded directly to each other, but the sheets 38 are preferred because 
they add great strength to the composite structure, much more than they 
have by themselves, when bonded to grids produced in accordance with the 
invention. 
FIGS. 4-10 show the basic principles of operation of the invention. Prior 
to the description thereof, an understanding of certain terms will be 
helpful. 
The grids produced by the invention are shown in FIG. 2. Referring to those 
figures, one can first think of the grid as having a plane. The cells have 
axes and they are perpendicular to the plane of the grid. The bars define 
the cells, and together constitute the grid. The thickness of the grid bar 
is measured in the plane of the grid. The height of a grid bar is measured 
perpendicular to the plane of the grid, i,e., parallel to the axes of the 
cells. The heights of the grid bars define the thickness of the grid 
overall. 
The invention utilizes much of the same apparatus as prior U.S. Pat. No. 
4,702,870. Compare FIG. 1 of that prior patent with FIGS. 4-7 of the 
present invention. Thus, the invention, in its simplest form, comprises a 
carrier 18 which carries a plurality of elastomeric pads 20. Carrier 18 
can be a screen formed of a suitable metal or synthetic material. 
Referring now to FIG. 4, fibers 22 are carried in a suitable carrier fluid 
and are flowed through the carrier, screen or support 18 and around the 
pads 20. This deposition of the fibers is shown in FIG. 4, the arrows 
indicating the passing of the carrier fluid, air, water, or other fluids, 
through the deposited fibers and the carrier or screen 18. FIG. 5 shows 
the end of the fiber deposition step. The amount and type of fibers used 
and provided in the carrier fluid is such that the fibers fill up only the 
spaces between the pads, and do not deposit on top of the pads, as is 
illustrated in FIG. 5. This is one of the main differences from the prior 
invention of U.S. Pat. No. 4,702,870, as can be seen by comparing FIG. 5 
herein with FIG. 3 of that prior patent. 
Referring to FIG. 5 again however, it should be borne in mind that the 
invention is not limited to filling the spaces between the pads completely 
Certain applications of use of the invention may dictate that the spaces 
between the pads will be filled only partially, for example, half-full or 
one-third full or the like. Such an option is easily within the ability of 
those skilled in the art. This variation, that is partial filling of the 
spaces between the pads, allows one set of pads on a screen to be used to 
produce grids of different sizes and performance characteristics. 
FIG. 6 illustrates consolidation of the fibers 22 deposited between the 
pads 22. To this end, pressing means 24 are provided. The pads 20 are 
compressed by a force applied normal to the plane of the grid to be 
produced, and normal to the screen 18. This is indicated by the force 
arrows in FIG. 6. 
The present invention, while it uses some of the same apparatus and 
techniques of prior U.S. Pat. No. 4,702,870, also uses different 
techniques. An important difference is the pressure applied and the kind 
of rubber used in the pads 20. Looking at FIG. 10 of the '870 patent, for 
example, it can be seen that when consolidation occurs, the sides of the 
pads take a substantially curved shape. Looking at the corresponding FIG. 
6 of the present application, it can be seen that the sides of the pads 
take a substantially straight configuration, as is required to produce the 
bars of the grids which are produced in accordance with the present 
invention. This difference comes from two sources. First, in general, 
higher pressures are used in the present invention. In the prior patented 
invention, the working pressure was usually well below 100 psi, and the 
range recited was 25 to 100 psi. In the present invention, the working 
pressure is usually above 100 psi, and the working range is 100 to 500 
psi. However, this range is not a limitation. The invention has been used 
to produce grids at pressures as low as 3 psi. Further, it is thought that 
higher pressures, even significantly higher pressures, than 500 psi can be 
used. It is thought that pressures as high as 1,000 psi could be 
successfully used in accordance with the teachings of the invention. 
Further, it is anticipated that, when brought to commercial application, 
the present invention may use softer grades of rubber for the pads 20 than 
were used in the 4,702,870 patent. This will enhance the straight sides on 
the pads to make the grid bars straighter in the present invention. But, 
substantially straight sides often are desirable in the present invention, 
and thus the increase in pressure and the change of rubber composition are 
utilized to accomplish that goal in the present invention. 
It should be noted that the pads 20 compress under the pressure and deform 
outwardly parallel to the screen while still maintaining a substantially 
straight configuration, as shown in the drawings. Thus, the grid bars are 
consolidated in both the vertical and horizontal directions. The vertical 
direction corresponds to the height of the bars of the grid produced, and 
the horizontal consolidation corresponds to the thickness of those bars. 
FIG. 7 shows the pressing means 24 removed, the pads returned to their 
relaxed state, and the resultant consolidated grid shown in place on the 
mold between the pads 20. 
The force arrows and pressing means 24 shown in FIG. 6 could represent 
platens, rollers, or other means to apply pressure to consolidate the 
grid, all of which is within the scope of well developed technology and 
known to those skilled in these arts. 
FIG. 8 shows the grid 16 removed from the mold. Bars 28 make up the grid 
16, and they define the open cells therebetween. 
The grid 16 produced, pressed from one side only, is usable just as shown 
in FIG. 8. However, in certain applications, and with certain fibers or 
mixtures of fibers, it may be desirable to produce a grid which is 
stronger, and wherein the bars are shorter, but denser and stronger, than 
those shown in FIG. 8. Such a grid 16-2 having bars 32 is shown in FIG. 
9C. The manner of its production is shown in FIGS. 9A and 9B. 
To do the second consolidation or pressing, see FIG. 9, the grid 16 
produced at the end of the processes of FIGS. 4-7 is inserted into a 
second mold made up of support 18A and pads 20A, such that the sides of 
the grid bars formed opposite from support 18 are now next to support 18A 
with the bars between elastomeric pads 20A. The pads 20A can be 
dimensioned to more accurately control the dimensions of the grid 16-2 
produced by the second pressing. Likewise, the spacing of the pads 20 can 
be different from that shown in FIGS. 4-7. That is, if it is necessary to 
go to the effort of a second pressing, there is additional versatility 
afforded by the methods of the invention in order to control the 
configuration of the final grid 16-2 and its bars 32, see FIG. 9C and 
compare it to FIG. 8. 
As can be seen from a comparison of FIGS. 8 and 9C in the panel produced 
after consolidation or a pressing from both sides, the ribs are shorter 
and the bars 32 are also considerably denser and stronger than are the 
bars 28 produced after only a single consolidation or press in accordance 
with that embodiment of the invention. FIG. 9C also indicates that the 
double pressed grid carries a different reference numeral, numeral 16-2, 
to indicate consolidation or pressing from both sides and to differentiate 
it from grid 16 pressed from only one side. This designation 16-2 will be 
used again in other Figures and in the discussion herein. 
This trade-off of the second step, together with its cost and effort, is 
also weighed against the differences in the two products. That is, the 
FIG. 8 single consolidation bars may be desirable where the added strength 
is not needed and the added larger dimensions are more important On the 
other hand, the smaller, denser, stronger bars of FIG. 9C may be worth the 
extra effort of the second consolidation in other end use situations. 
The grid 16 is inserted from the opposite direction into the mold made up 
of the parts 18a and 20a. Then pressure means 24 are applied, in the 
manner shown in FIG. 6. The consolidation process, utilizing FIG. 9B, is 
thus similar to that shown in regard to FIG. 6 and described above, except 
for the differences described. 
In both cases, that is, the grid 16 produced at the end of the single 
pressing operation, or the grid 16-2 produced at the end of the double 
pressing operation, the grid is then dried, any adhesive used is cured, 
and other finishing processes well within the normal technology of this 
art is applied to complete the grid 16 or 16-2 and make it a finished 
product. Where non-cellulose fibers are used, some of the fibers may be 
actually melted in order to cure the mat into the grid 16 or 16-2. 
It is desirable to reverse the grid 16 with respect to the trapezoidal 
spaces between the pads 20A when using the second press procedure of FIG. 
9. There are many reasons for this One reason is that any discontinuity or 
difference in pressure that might have occurred in the first press is 
compensated for by the second press when the grid is inserted in the 
reverse direction. This reversal also tends to reduce the size of the 
fillets at the top and bottom of the grid bars, i.e., a straighter, 
flatter, grid bar is produced by the second pressing. Also, any stray 
fibers, which may be an annoyance in the grid 16 produced by a single 
press, are consolidated into the grid bars in the second press, thus 
producing a neater, cleaner looking grid as a result of the second press 
of FIG. 9. 
Yet another option is illustrated in FIGS. 10A and 10B. In this case, the 
grid is changed in character after it is formed but before it is cured or 
otherwise finished This grid 34 can be either the grid 16 formed after the 
single pressing, or the grid 16-2 formed after the double pressing The 
grid is taken off of the mold, and put by itself in the pressing means 24. 
At least a single pressing would be required so that the grid would have 
sufficient strength to be taken off of the mold and moved to a work 
station such as shown in FIG. 10A. The resultant grid 34 is shown by 
itself in FIG. 10B. Again, final steps such as drying and curing would be 
needed to produce a finished product. 
The basic principles of the operation of the invention shown in and 
described with respect to FIGS. 4-10 are applicable to both a batch or a 
continuous type of process. The remaining FIGS. 11, 12 and 13 illustrate 
further variations and constitute additional teaching in regard to 
embodiments of the invention wherein the grids, both single and double 
consolidation grids, are produced in a continuous manner. 
FIG. 11 shows two different forming methods for deposition or forming of 
the grid. FIG. 12 shows several different variations of the pressing and 
forming of the grid. FIG. 13 shows several variations of drying and curing 
or finishing of the grid. 
It is within the teaching of the invention, and in fact it is a facet of 
its versatility, that either of the two forming processes of FIG. 11 could 
be used with FIGS. 12A, 12B, or 12C. If pressing from both sides is 
desirable, then either of FIGS. 12A or 12B would be followed by FIGS. 12D, 
12E, or 12F. Drying of the grid of FIGS. 12A-12E can be done with any one 
of the processes of FIG. 13. The exact combination which would be used is 
dependent on the fibers, the end result desired, the sizes, and other 
parameters surrounding any particular use situation. 
FIG. 11 shows two continuous forming methods that can be used in accordance 
with the invention. FIG. 11A is a simplified drawing of a forming section 
known in the art as a Fourdrinier forming section. FIG. 11B is a 
simplified drawing of a cylinder forming machine. Either can be used in 
accordance with the teachings of the invention. The elements 40 shown in 
FIG. 11 are vacuum boxes or the like which assist in forming the grid 16 
on the moving belt, in a more or less conventional manner for this kind of 
apparatus. 
In FIGS. 12A, 12B and 12C, a cylinder forming machine is shown in 
combination with three different types of pressing arrangements. The 
Fourdrinier forming section of FIG. 11A could just as well be used. 
Likewise, other means known in the art could be used. 
FIG. 12A shows the special screen on the cylinder former only. A press 34 
is positioned at the top of the cylinder to press the fiber mat and the 
elastomeric pads 20. Thereafter, the fiber grid has sufficient strength to 
be lifted from the screen and transferred to roll presses 36. The rolls 36 
are the counterpart of the pressing means 24 of the earlier figures. The 
result of this process of FIG. 12A would be analogous to the grid 34 of 
FIG. 10B, i.e., a short, squat grid with relatively thick bars. 
In FIG. 12B, the special screen extends off of the forming cylinder around 
other rollers, and then returns to the underside of the cylinder The large 
diameter press 36 could be similar to a state of the art extended nip 
press built by Beloit Corporation of Beloit, Wisconsin, or a similar such 
wide nip press, or similar wedge press. 
The schematic showing 36 in FIG. 12B could be either a roller or, more 
accurately for that Figure, a kind of pressing device called a shoe nip. A 
more accurate schematic representation of a roller nip pressing device is 
shown in FIG. 12D. The two are interchangeable, but, in many cases, the 
shoe nip of FIG. 12B is preferred. 
In FIG. 12C, the special screen, together with the grid, are carried 
together into one of the drying schemes. That is, the special screen 
carrying the pads is long enough to extend right through forming, pressing 
and curing. The curing is done after FIGS. 12A and 12B in any of the forms 
of FIG. 13. 
FIGS. 12D, 12E, and 12F show three of the many possible means to produce 
the double consolidated or pressed grid 16-2 of FIGS. 9B and 9C described 
above A second set of pads, as described above, are inserted into the 
cells of the once consolidated (but not yet cured and finished) grid 16 
from the side opposite that from which the first set of pads were 
inserted, and then a second consolidation or pressing applied to the first 
grid 16 to produce the second grid 16-2. 
In FIG. 12D, the grid structure 16 produced from any of the prior FIG. 12 
versions, is fed into a press 36 having the pads attached to the drum as 
shown in the drawing These pads are slightly different from the first set 
of pads (see the discussion of this point about the two sets of pads 
above). A press felt 42 is used to assist in gently pushing the already 
formed cells in the grid 16 onto the pads on the drum 36. As discussed 
above, this drum can be either a shoe nip as shown in FIG. 12B or a roller 
drum as shown in FIG. 12D. It is thought, at present, that a shoe nip 
might be better, but that is, of course, dependent upon the parameters of 
the particular embodiment in use. Further, felt 42 can also be used to 
absorb water or other fluid that might still be present in the not yet 
dried grid 16. Dryer felts such as item 42 are well known in this art, 
they are tensioned to apply a very slight holding, and in the case of FIG. 
12D, application pressure; a pressure in the range of 0.5 to 2 psi holding 
pressure is very typical. 
It should be noted that the pads in these FIGS. 12D, 12E, and 12F are 
inserted from the side opposite that in which they were inserted in FIGS. 
12A, 12B or 12C which form a single pressed grid 16. 
FIG. 12E shows a variation wherein the second set of pads are provided on a 
continuous or closed loop screen 44. The method of operation and product 
is otherwise identical to that of FIG. 12D, including the felt 42, as 
described above. 
As indicated in regard to FIGS. 12A-12E, the grid produced, be it 16 or 
16-2, is then fed on to FIG. 13 for drying and finishing. FIG. 12F shows a 
composite second press and drying arrangement which comprises a continuous 
pressure dryer 46. A dryer felt 43 is also used, together with a 
continuous screen carrying the pads for the second press The arrangement 
of FIG. 12F applies continuous pressure and, if desired, heat, so that the 
end product of FIG. 12F is finished grid, i.e., none of the variations of 
FIG. 13 are required in conjunction with FIG. 12F. 
FIG. 13 shows various kinds of drying or curing arrangements which can be 
used in conjunction with the invention. Other such conventional means can 
also be used. 
FIG. 13A shows a high velocity hot air impingement type of drier wherein 
hot air is blown from the top and/or the bottom to dry the fiber grid. 
Note that there is no pressure applied normal to the grid in this form. 
FIG. 13B shows a typical arrangement of a drum dryer as used in the paper 
industry. In this case, there is a small amount of pressure applied to the 
grid normal to the grid. This may be desirable in certain situations, and 
may be of no interest, that is, of no consequence, depending upon the 
particular grid produced. 
Finally, FIG. 13C shows a continuous type press. Continuous presses are 
used in the industry to make hardboard and particle board products. 
Continuous presses can apply a large pressure normal to the grid going 
through the drying process. In all three of these cases of FIG. 13, the 
grid alone or the grid together with the screen can be used to go through 
the drying/curing or the like means to finish the grid. 
While the invention has been described in some detail above, it is to be 
understood that this detailed description is by way of example only, and 
the protection granted is to be limited only within the spirit of the 
invention and the scope of the following claims.