Molding deformable materials with use of vibrating wall surfaces

An apparatus for shaping, and/or directing the flow of deformable materials, wherein the apparatus includes a novel vibrating wall assembly having at least one surface which defines a specific geometric shape over which the deformable material will pass. The novel vibrating wall assembly of this present invention includes the following components: (a) a plurality of pulsating, polygonally-shaped surface elements which are movable between a resting position and an energized position; (b) an energizing device for moving at least one of the plurality of pulsating surface elements from its resting position to its energized position, to form an energized surface element; (c) a biasing device for moving the energized surface element from its energized position back to its resting position; and (d) a linking device for interconnecting the plurality of pulsating surface elements, wherein the linking device allows for the limited pulsating movement of the plurality of pulsating surface elements.

FIELD OF THE INVENTION 
The present invention relates to a method and apparatus for controlling 
and/or altering the physical characteristics of a deformable material. 
Particularly, the invention pertains to a method and apparatus for 
shaping, and/or directing the flow of, a deformable material, by the 
implementation of a vibrating wall surface, to control and/or modify the 
molded product's physical properties. This invention also pertains to a 
molded product resulting from being subjected to the vibration process as 
disclosed herein. 
BACKGROUND OF THE INVENTION 
The processing of deformable materials generally involves the 
transformation of a starting material (i.e., in a solid state or a liquid 
state), which is in a random form (e.g., powder, beads, granules, pellets, 
etc.), into a final or intermediate product having a specific shape, 
dimensions and properties. Processes useful in the transformation of 
deformable materials from their initial random form to the form of the 
final or intermediate product are well known to those skilled in the 
materials processing industry. For instance, if the deformable material is 
a plastic, examples of such plastic transformation processes include, but 
are not limited to: extrusion, transfer molding, calendaring, laminating, 
thermoforming, injection molding, compression molding, blow molding and 
the like. As used herein, such transformation processes and/or operations 
are collectively referred to as "molding" processes. Similarly, the 
resulting final or intermediate product is referred to as "molded", 
regardless of the specific transformation process employed in its 
manufacture. The materials processing industry is abundant with teachings 
in this field of technology. 
Most of the conventional molding processes include at least the following 
steps: (a) transporting an unmolded, deformable material to a molding 
device, (b) heating the unmolded, deformable material until it can be 
deformed to take the geometric configuration of the mold or die, (e) 
shaping the heated material to the geometric configuration of the mold or 
die to form a molded product, and (d) cooling the molded product. These 
steps can be done either in sequence or simultaneously or a combination of 
both. 
In order to produce molded products having a specific geometric 
configuration, it is generally necessary to employ a mold or die. The 
primary objective of a mold or die is to shape the deformable material 
introduced therein. Sometimes, molds and dies have a secondary objective, 
this being to cool the deformed material therein until it is able to 
maintain its shape when the molded product is withdrawn therefrom. 
The physical properties of a molded product depend, in part, upon the 
specific molding process conditions and steps employed. It has been 
observed that different molding processes will often result with the final 
or intermediate products having different physical properties. For 
example, the amount of shear stress in a molded product determines, in 
part, the degree of molecular orientation and crystallization within the 
molded product. This, in turn, has an affect on the molded product's 
physical properties. 
Since there is a need to be able to produce molded products which have 
physical properties within particular ranges, if a means can be devised 
for controlling at least some of these physical properties (e.g., by 
controlling the degree of shear stress) both the process and the product 
resulting therefrom will be greatly welcomed in the molding industry. 
One method of controlling the amount of shear stress in a molded product 
(and thereby controlling some of the product's physical properties), is 
commonly referred to as "flow technology". The concept of "flow 
technology", as it relates to plastic molding processes, is concerned with 
the behavior of a deformable plastic material before, or while, it is 
being introduced into a mold and/or being passed through a die. 
It has been discovered that the properties of a final or intermediate 
molded product depend largely upon how the deformable material flows prior 
to, and/or while, being subjected to a molding process. For example, two 
products, having identical dimensions and made from the same basic 
starting material, but which are molded under different conditions (e.g., 
different hydrostatic pressures and/or shear stresses) and subjected to 
different flow patterns, will probably have different physical properties. 
This phenomena is due, in part, to the fact that, as a deformable material 
flows prior to, or while, entering a mold or passing through a die, it is 
subjected to a shear stress which is commonly referred to herein as "flow 
shear stress". 
Flow shear stress induces molecular orientation in the plastic material 
(i.e., it results in the macromolecules aligning themselves in the 
direction of flow). The flow shear stress varies from a maximum level at 
the outside surface of the flowing deformable material to a minimum level 
at the center where the material is last to cool. 
From the above it can be seen that the manner in which the deformable 
material flows into a mold or through a die, or prior to being subjected 
to a specific molding process, is of extreme importance in determining the 
physical properties of the final molded product due, in part, to the 
degree of flow shear stress which will be imparted thereto. 
If a means can be devised for controlling the degree of molecular 
orientation resulting from flow shear stress, it would be greatly welcomed 
in the molding industry since it will enable the manufacturer to have a 
greater degree of control over the product's final properties. 
As is well known in the molding industry, during the compensating phase of 
a typical injection-molding process, the flow of a deformable material 
into the mold is generally unstable due to the flow occurring in "rivers" 
which spread out in a delta-like manner. The first material to freeze off 
shrinks early in the cycle. By the time the material freezes in these 
"rivers", the bulk of the material is frozen up and the shrinkage has 
already occurred. Therefore, the rivers shrink relative to the bulk of the 
molded article. 
Since the rivers are highly oriented, shrinkage can be very high. This, in 
turn, can result in high degrees of stress inside the molded part which 
can, for example, be a source of warpage. Accordingly, if a means can be 
devised which reduces the degree of shrinkage from the "rivers" and, thus, 
reduces the degree of warpage in the final product, it would also be 
greatly welcomed in the molding industry. 
It has also been discovered that the micro structures and the morphology of 
a molded product (e.g., molecular orientation, degree of crystallinity, 
etc.) are greatly influenced by the thermo-mechanical history experienced 
by a deformable material during its molding process steps. And, as can be 
expected, the ultimate properties of the molded product are closely 
related to the deformable material's morphology and micro structure. 
Specifically, according to U.S. Pat. No. 4,469,649, which is incorporated 
herein by reference, the control of a material's transformation process, 
from its random form to its final molded form, can be made at least 
partially dependent upon the rheological properties of the plastic 
material as it is subjected to specific molding techniques. 
If a means can be devised to control the micro structures and the 
morphology of a molded deformable product, it would be greatly welcomed in 
molding industry. 
As can be seen from the above, while molded products (e.g., plastics) play 
a significant role in our daily lives, and are expected to play an even 
more important role in our future, there are many problems in the 
manufacturing of such products which still remain unsolved. 
SUMMARY OF THE INVENTION 
Accordingly, it is one object of the present invention to provide a means 
for improving the physical properties of a molded product which has been 
subjected to a specific molding process by controlling the amount of shear 
stress within the final or intermediate product. 
Another object of this present invention is to provide a new flow 
technology concerned with the behavior of deformable materials during the 
transformation process from their initial form to their final molded form. 
It is yet another object of the present invention to subject a mold or die 
surface to a novel vibrational treatment to control the manner in which a 
deformable material flows into or through the mold or die. This novel 
vibrational treatment accomplishes at least one of the following 
objectives: (a) it eliminates at least some of the presence of rivers 
resulting within the molded product; and/or (b) it minimizes the degree of 
shrinkage during the solidification stage. 
It is even another object of this invention to provide a novel mold or die 
surface which provides, in a material being molded therein and/or passed 
therethrough, an optimum degree of orientation through shear plastic 
yielding occurring during and/or just before the solidification stage. 
It is still another object of this invention to provide a novel mold or die 
surface which can influence the way that a deformable material flows 
therein or therethrough, thereby altering the physical properties of the 
molded product. 
It is a further object of this invention to provide an extrusion apparatus 
having the capability of altering the physical properties of a deformable 
material flowing therethrough. 
It is even a further object of this invention to implement the novel mold 
and/or die surface design disclosed herein with the specific molding 
technology disclosed in U.S. Pat. No. 4,469,649 in order to improve the 
physical properties of a molded product by controlling the manner in which 
a deformable material flows into a mold and/or through a die. 
It is still a further object of this invention to implement the novel mold 
and/or die surface design disclosed herein with the specific molding 
technology disclosed in U.S. Pat. No. 4,919,870 (also incorporated herein 
by reference). 
These and other objects are met by the present invention, due to the 
implementation of an apparatus for shaping, and/or directing the flow of, 
deformable materials, wherein the apparatus comprises a novel vibrating 
wall assembly having at least one surface which defines a specific 
geometric shape. In this present invention, the deformable material passes 
over at least one surface of this novel vibrating wall assembly. By 
controlling the amount, frequency, and/or amplitude of vibration, the 
physical properties of the resulting molded product can be controlled 
and/or altered. 
The novel vibrating wall assembly of this present invention comprises the 
following components: 
(a) a plurality of pulsating, polygonally-shaped surface elements which are 
movable between a resting position and an energized position; 
(b) an energizing means for moving at least one of the plurality of 
pulsating surface elements from its resting position to its energized 
position, to form an energized surface element; 
(c) a biasing means for moving the energized surface element from its 
energized position back to its resting position; and 
(d) a linking means for interconnecting the plurality of pulsating surface 
elements, wherein the linking means allows for the limited pulsating 
movement of the plurality of pulsating surface elements. 
In one embodiment of the present invention, the novel vibrating wall 
assembly comprises, among other things, a plurality of pulsating, 
polygonally-shaped surface elements which collectively define at least one 
surface of the specific geometric shape (e.g., flat, cylindrical, 
polyhedronal, abstract, etc.) over which the deformable material will 
pass, when the pulsating surface elements are in their resting position. 
Accordingly, when one of the pulsating surface elements is in an energized 
position, a deformation in the surface of the specific geometric shape 
results. The linking means of this embodiment interconnects the plurality 
of pulsating surface elements in a manner which allows for their 
controlled, limited pulsating movement. In another embodiment of the 
present invention, the novel vibrating wall assembly comprises, among 
other things, a plurality of pulsating, polygonally-shaped surface 
elements and at least one non-pulsating, polygonally-shaped surface 
element. Here, the plurality of pulsating surface elements and the at 
least one non-pulsating surface elements collectively define at least one 
surface of the specific geometric shape (e.g., flat, cylindrical, 
polyhedronal, abstract, etc.) over which the deformable material will 
pass, when the plurality of pulsating surface elements are in their 
resting position. Moreover, the linking means of this latter embodiment 
interconnects the plurality of pulsating surface elements and the at least 
one non-pulsating surface element together. Here, as with the former 
embodiment, the linking means still must allow for the controlled, limited 
pulsating movement of the pulsating surface elements. 
Other objects, aspects and advantages of the present invention will become 
more apparent to those skilled in the art upon reading the following 
detailed description, when considered in conjunction with the appended 
claims and the accompanying drawings briefly described below.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention provides a novel apparatus which is useful for 
shaping, and/or directing the flow of, deformable materials. This novel 
apparatus comprises at least one vibrating wall assembly which defines at 
least one of the surfaces of a specific geometric shape over which a 
deformable material will pass. 
Specifically, the at least one surface of a specific geometric shape over 
which the deformable material will pass, which is defined by the vibrating 
wall assembly of the present invention, is at least partially made up of a 
by plurality of interwoven pulsating surface elements. These interwoven 
surface elements are also referred to herein as "bricks". It is also 
within the scope of this invention for the vibrating wall assembly to also 
include at least one non-pulsating surface element. 
The specific geometric shape defined by the vibrating wall assembly of the 
present invention can be employed as at least part of a surface of a 
molding apparatus over which a deformable material will pass. For example, 
the vibrating wall assembly can define at least part of a surf ace of a 
mold, a die, and/or a transfer channel to and/or from the mold or die. 
When practicing this invention, the pulsating surface elements are put into 
a periodic pulsating motion via an energizing means and a biasing means. 
While the surface elements are pulsating, a deformable material passes 
thereover. 
Any suitable energizing and/or biasing means can be employed to cause these 
surface elements to pulsate. Examples of such suitable means include, but 
are not limited to: mechanical means, electrical means, magnetic means, 
electro-magnetic means, hydraulic means, pneumatic means, and the like, 
and/or any combination thereof. Specific examples of energizing and/or 
biasing means will be discussed later in more detail. 
One of the many features of the present invention comprises the creation of 
novel vibrating wall surfaces which can be employed in an apparatus 
suitable for shaping, and/or directing the flow of, deformable materials. 
These novel vibrating wall surfaces define at least one surface of a 
specific mold or die geometric shape (e.g., flat, cylindrical, 
polyhedronal, abstract, etc.). These novel vibrating wall surfaces can 
have any desired texture and/or geometric shape. Generally, if these 
vibrating wall surfaces are employed as part of a specific mold or die, 
their shape will depend largely upon the desired shape of the molded 
product. Similarly, their surface texture will also depend largely upon 
the desired texture of the molded product. 
In accordance with the present invention, the novel vibrating wall assembly 
comprises a plurality of individual pulsating surface elements. These 
pulsating surface elements are movable between a resting position and an 
energized position. This pulsating movement results in the formation of a 
novel vibrating wall assembly. Since the novel vibrating wall assembly of 
the present invention is employed in an apparatus which is suitable for 
shaping and/or directing the flow of deformable materials, and since the 
novel vibrating wall assembly also defines at least one surface of a 
specific geometric configuration over which the deformable material will 
pass, through this pulsating action, periodic or static pressure is 
exerted on the deformable material passing thereover. 
As stated earlier, the novel vibrating wall assembly of the present 
invention comprises, among other things, a plurality of pulsating, 
polygonally-shaped surface elements which collectively define at least one 
surface of a specific geometric configuration when the plurality of 
pulsating surface elements are in their resting position. However, when at 
least one of these plurality of pulsating surface elements is in its 
energized position, a deformation in the surface of the specific geometric 
configuration results. 
In addition to the plurality of pulsating surface elements, it is also 
within the scope of this invention for the novel vibrating wall assembly 
to optionally comprise at least one non-pulsating, polygonally-shaped 
surface element. In this latter embodiment, the plurality of pulsating 
surface elements and the at least one non-pulsating surface element 
collectively define at least one surface of a specific geometric shape 
when the plurality of pulsating surface elements are in their resting 
position. 
The pulsating and/or non-pulsating surface elements useful in the practice 
of this invention can have any suitable size, shape and geometric 
configuration which allows for the limited pulsating movement of pulsating 
surface elements. For example, if the surface defined by the vibrating 
wall assembly is planar, the plurality of pulsating and/or non-pulsating 
surface elements making up this particular vibrating wall assembly can 
have a square and/or rectangular configuration. Similarly, if the surface 
defined by the vibrating wall assembly is curved, the plurality of 
pulsating and/or non-pulsating surface elements making up this particular 
vibrating wall assembly can have a concave and/or convex configuration 
(for an illustration of this latter example, see FIG. 1). 
Since the geometric configurations of molds, dies and/or transfer channels 
employed in today's molding industry are infinite, so are the number of 
different sizes, shapes and geometric configurations of the plurality of 
pulsating and/or non-pulsating surface elements encompassed by the present 
invention. 
When selecting the specific geometric shape of the pulsating and/or 
non-pulsating surface elements, it is important to take into consideration 
the flowability of the deformable material which will pass over the 
vibrating wall assembly. Specifically, in most instances, it would not be 
desirable to have the flowable material seeping into the joints located 
between two adjacent surface elements. One method of overcoming this 
problem is by designing the surface elements such that, due to the flow 
rate and viscosity of the deformable material, the material does not seep 
into these joints. This may, however, hamper the mobility of the pulsating 
surface element in respect to one another. If so, another way of 
overcoming this problem is by placing a coating material or layer (e.g., a 
film) over the surface of the vibrating wall assembly. If employed, this 
coating must allow the surface elements to pulsate. Specifically, the 
coating should have a thickness and resiliency associated therewith such 
that it can withstand the pulsating effect of the vibrating wall assembly 
while still transmitting this pulsating effect to the material passing 
thereover. 
Any suitable coating material can be employed. The specific coating 
material will depend, in part, upon the desired function sought thereby. 
For example, if a non-stick coating material is desired, 
polytetrafluoroethylene and/or polybichloril-difluoril-ethylene can be 
used. 
The surface elements of the present invention can be made from any suitable 
material known to those skilled in the art. The specific selection of a 
suitable material from which to make the surface elements of the present 
invention will depend, in part, upon the specific temperature, pressure 
and vibrational conditions to which they are subjected by the specific 
molding process employed. For example, if the deformable material being 
shaped, or whose flow is being directed, is a plastic, a suitable 
composition from which that surface of the pulsating and/or non-pulsating 
surface elements which contacts the plastic can be made is a nickel-chrome 
steel. 
In addition to a plurality of pulsating and/or non-pulsating surface 
elements, the vibrating wall assembly of the present invention also 
comprises a means for moving at least one of the plurality of pulsating 
surface elements from its resting position to an energized position. 
Generally, the energizing means exerts a positive and/or negative pressure 
onto at least one of the pulsating surface elements such that a 
deformation is observed in the surface of the specific geometric 
configuration defined by the vibrating wall assembly. This positive and/or 
negative pressure is, preferably, perpendicular to the flow of deformable 
material over the novel vibrating wall assembly. 
Any suitable means can be employed for moving at least one of the plurality 
of pulsating surface elements from its resting position to an energized 
position. Examples of suitable energizing means which can be employed when 
practicing this invention include, but are not limited to: mechanical 
energizing devices, electric energizing devices, magnetic energizing 
devices, electromagnetic energizing devices, hydraulic energizing devices, 
pneumatic energizing devices, and the like and/or any combination thereof. 
For example, in FIG. 13a, rod 100 pushes against the inside wall surface 24 
of surface element 20. This pushing action energizes the surface element 
and results with its upper wall surface 22 moving from its resting 
position to its energized position. 
The movement of rod 100 is due to energizing means 102. This energizing 
means can be an electrical energizing device, a magnetic energizing 
device, an electro-magnetic energizing device, a hydraulic energizing 
device, a pneumatic energizing device, and the like, and/or any 
combination thereof. Moreover, it can also be a solenoid unit or a 
piezoelectric unit. 
In the specific embodiment illustrated in FIGS. 7, 8 and 11 of the present 
invention, the outside wall surface of the novel vibrating wall assembly 
defines the inside wall surface of an extrusion die. There, the energizing 
means employed comprises a series of longitudinally-oriented push rods 
which exert a positive pressure on the inside wall surface of the 
vibrating wall assembly. This positive pressure temporarily energizes the 
pulsating surface element. When the push rods cease to contact the 
underside of those particular pulsating surface elements, the biasing 
means returns the energized elements back to their original resting 
position. Depending on the viscosity and pliability of the material 
flowing thereover, this material may also contribute to returning 
energized elements back to their original resting position. This specific 
process will be described later in more detail. 
It is also within the scope of this invention to employ a solenoid-type 
unit and/or a piezoelectric unit as an energizing means (see, for example, 
FIG. 13a). Here, the solenoid-type and/or piezoelectric unit(s) would be 
attached to at least one of the pulsating surface elements. Then, by 
energizing the unit(s), the pulsating surface element(s) will also be 
energized. 
The vibrating wall assembly of the present invention also comprises a means 
for moving at least one of the pulsating surface elements from its 
energized position back to it original resting position. Generally, this 
biasing means exerts a pressure opposite to that of the energizing means, 
such that the deformation observed in that surface of the specific 
geometric configuration defined by the vibrating wall assembly, is 
removed. 
Any suitable biasing means can be employed to return a pulsating surface 
element from its energized back to its original resting position. Examples 
of suitable biasing means which can be employed when practicing this 
invention include, but are not limited to: mechanical biasing devices 
(e.g., springs, bands, cables, O-rings, etc.), electrical biasing devices, 
magnetic biasing devices, electro-magnetic biasing devices, hydraulic 
biasing devices, pneumatic biasing devices, and the like, and/or any 
combination thereof. 
For example, in FIG. 13b rod 100 pulls surface element 20 from its 
energized position to its resting position by biasing means 106. This 
biasing means can be an electrical biasing device, a magnetic biasing 
device, an electromagnetic biasing device, a hydraulic biasing device, a 
pneumatic biasing device, and the like, and/or any combination thereof. 
It is also within the scope of this invention for the energizing means and 
the biasing means to be a single unit. For example, in FIGS. 13a and 13b, 
when rod 100 is moving in an upward direction, it is pushing surface 
element 20 from its resting position to its energized position. On the 
other hand, when rod 100 is moving in a downward direction, it is pulling 
surface element 20 from its energized position to its resting position. 
In the specific embodiment of the vibrating wall assembly illustrated in 
FIGS. 3, 5-8 and 11 of the present invention, the biasing means employed 
comprises a continuous, resilient band which is fitted into a camphor or 
groove notched into the side walls of radially-adjacent surface elements. 
This specific band and groove configuration tightly holds those surface 
elements within a single radial plane in their resting position when no 
energizing force is applied thereto. However, when an energizing force is 
exerted onto any one of the pulsating surface elements via any suitable 
energizing means (e.g., push rods), this strains the biasing means. 
Accordingly, when the energizing force is removed, the biasing means seeks 
to remove the strain by returning the energized surface element back to 
its original resting position. As stated above, this specific process will 
be described later in more detail. 
Since the vibrating wall assembly of the present invention is comprised of 
a plurality of pulsating and/or non-pulsating surface elements, this wall 
assembly also includes means for interconnecting these surface elements 
together such that they collectively define at least one relatively 
continuous surface of a specific geometric configuration. The linking 
means useful in practicing the present invention must allow for the 
limited pulsating movement of the pulsating surface elements. It is also 
desirable, although not necessary, for the linking means to interconnect 
the plurality of pulsating and/or non-pulsating surface elements together 
such that substantial seepage of deformable material into the joints 
located between two adjacent surface element does not result. 
Any suitable linking means can be employed when practicing this invention 
which has associated therewith the aforementioned characteristics. 
Examples of suitable linking means include, but are not limited to: rods, 
cables, plates, bands, tubes, and the like, and/or any combination 
thereof. 
FIGS. 14a, 14b and 14c illustrate embodiments of the invention wherein the 
linking means are cables, tubes and plates, respectively. 
In the specific embodiment of the vibrating wall assembly illustrated in 
FIGS. 3, 5-8 and 11 of the present invention, the linking means employed 
comprises a series of longitudinally-oriented rods which pass through 
corresponding openings defined through longitudinally-adjacent surface 
elements. While these openings can have any suitable configuration (e.g., 
circular, elliptical, elongated, square, rectangular, triangular, 
polygonal, etc.), they must allow for the limited pulsating movement of 
the pulsating surface elements while the linking means is passed 
therethrough. 
The figures of the present invention illustrate, among other things, 
specific pulsating surface elements, specific energizing means, specific 
biasing means and specific linking means, as well as a specific 
implementation of a novel vibrating wall assembly in an extrusion molding 
apparatus. As stated earlier, any suitable surface element, energizing 
means, biasing means and/or linking means can be employed when practicing 
the present invention. Also as stated earlier, the novel vibrating wall 
assembly of the present invention can be employed with any suitable 
apparatus useful for shaping, and/or directing the flow of, deformable 
materials. Such suitable vibrating wall assembly components and uses will 
be apparent to those skilled in the art once reading the description of 
the present invention as set out herein. 
Referring now to FIG. 1, this illustrates a front planar view of a 
pulsating surface element employed in the fabrication of a cylindrical 
vibrating wall assembly useful as part of an extrusion die. FIG. 2, on the 
other hand, is a cross-sectional view of the surface element illustrated 
in FIG. 1 taken along line 2--2. 
The surface element illustrated in FIGS. 1 and 2 is generally represented 
by reference numeral 20. Surface element 20 has an outer wall surface 22, 
an inner wall surface 24 and opposing side wall surfaces 34 and 35. 
In practice, a plurality of pulsating surface elements are placed adjacent 
one another until their collective upper lower surface create a vibrating 
wall assembly having at least one surface which defines a specific 
geometric configuration over which a deformable material will pass. An 
example of a plurality of surface elements collectively employed to form a 
vibrating wall assembly having a cylindrical configuration is illustrated 
in FIGS. 4, 5, 7, 8 and 11. These Figures will be discussed later in more 
detail. 
As stated earlier, the joints located between two side walls of adjacent 
surface elements should be: (a) tight enough such that a substantial 
amount of the deformable material being molded does not flow therebetween 
and (b) loose enough such that the pulsating surface elements can pulsate. 
As also stated earlier, while the former characteristic is not necessary, 
it is desirable. 
The tightness/looseness of these joints will depend, in part, on the 
following variables: the viscosity of the deformable material passing over 
the vibrating wall assembly, the specific apparatus into which the 
vibrating wall assembly will be incorporated, the desired shape and 
configuration of the vibrating wall assembly, the specific energizing 
means employed, the specific biasing means employed, and the like. As for 
the viscosity, U.S. Pat. No. 4,469,649 states that it may be a function of 
the vibrating walls' pulsating frequency. Accordingly, the preferred 
surface element design employed will depend largely upon the specific 
parameters selected by the one practicing this invention. 
As stated earlier, one of the many features of the present invention is 
that it provides a novel vibrating wall assembly which can exert a 
periodic positive and/or negative pressure on a deformable material 
passing thereover. The manner in which this pressure is exerted onto the 
deformable material in accordance with the present invention is by the 
limited, pulsating movement of individual surface elements. In one 
preferred embodiment, this pulsating movement is in a direction which is 
generally perpendicular to the flow of the deformable material flowing 
thereover. 
In another preferred embodiment the pulsating elements are tilted in the 
direction of flow. Here, the pulsating elements would also result in 
pushing the material passing thereover. And, depending on the specific 
factors, these tilted pulsating elements can even stretch the material 
flowing thereover. 
When practicing the present invention, energizing means is employed for 
moving the pulsating surface elements from their original resting position 
to an energized position. This energizing means can be in either direct or 
indirect contact with the individual pulsating surface elements. 
Referring to the specific surface element design illustrated in FIGS. 1-6 
of the present invention, the deformable material will come into contact 
with either the surface element outer wall 22 or the surface element inner 
wall 24, depending upon the specific molding process. In this embodiment, 
the energizing means is generally in either direct or indirect contact 
with that surface element wall which is opposite the wall which comes into 
contact with the deformable material. 
An example of such an embodiment is illustrated in FIGS. 7, 8 and 11 of the 
present invention. In those specific embodiments, the deformable material 
comes into contact with surface element outer wall 22. Accordingly, the 
energizing means is in contact with surface element inner wall 24. These 
Figures will be discussed later in more detail. 
As stated earlier, the surface elements of the present invention also have 
associated therewith a linking means for interconnecting the individual 
surface elements to one another. Referring to the specific surface element 
design illustrated in FIGS. 3, 5-8 and 11 of the present invention, the 
linking means illustrated therein comprises a series of 
longitudinally-oriented rods 26 and radially-oriented bands 28. 
Specifically, in the embodiment illustrated in FIGS. 3, 5-8 and 11, rods 26 
are dimensioned to transversely pass through corresponding openings 30 
defined through longitudinally-adjacent surface elements 20. This is best 
illustrated by FIGS. 3 and 7. 
In these Figures, rods 26 are positioned in a direction which is generally 
parallel to the direction of flow of the deformable material over the 
vibrating wall assembly. One of the purposes of rods 26 is to 
longitudinally interconnect the plurality of surface elements. 
As can be seen by referring specifically to FIGS. 3 and 4, the positioning 
of longitudinally-adjacent surface elements can be staggered. By employing 
this design technique, it is possible for rods 26 to afford an even 
greater degree of interconnection between longitudinally-oriented surface 
elements. 
In the embodiment illustrated in FIGS. 3, 5-8 and 11 of the present 
invention, it can be seen that the diameter and geometric shape of rods 26 
are such that the pulsating surface elements can move from their resting 
position to their energized position when a positive or negative pressure 
is exerted onto their inner wall 24. By controlling the size and shape of 
rods 26, and/or openings 30 through which they pass, the amplitude of 
pulsation can also be controlled. 
In FIGS. 3 and 5-8 of the present invention, rods 26 and openings 30 have 
the same cross-sectional geometric shape (i.e., circular). Therefore, 
since the diameter of rods 26 is less than that of opening 30, limited 
movement of the pulsating surface elements 20 is possible when a positive 
or negative pressure is exerted by an energizing means onto the pulsating 
surface elements inner wall 24. 
It should be noted, however, that openings 30 need not necessarily have the 
same cross-sectional geometric shape as their corresponding linking means. 
Rather, opening 30 can have any suitable shape which: (a) is dimensioned 
to receive the specific linking means employed, (b) enables the 
interconnection of adjacent surface elements and (c) enables adjacent, 
interconnected pulsating surface elements to move from their original 
resting position to their energized position while they are linked 
together. 
An example of an embodiment where the holes passing through the surface 
elements do not have the same cross-sectional geometric shape as their 
corresponding linking means is illustrated in FIG. 11 of the present 
invention. There, the linking rods 26 have a circular cross-sectional 
shape, while the openings 30' have an elliptical cross-sectional shape. 
Such a design is useful for aiding in the alignment of corresponding holes 
passing through longitudinally-adjacent surf ace elements, especially if 
these surface elements are staggered (see, FIGS. 3 and 4) or different 
lengths (see, FIG. 11). 
Moreover, instead of being elongated in the direction of flow, the opening 
30 can be elongated in a perpendicular or slightly tilted orientation. 
Also, opening 30 can be designed such that, while a generally 
perpendicular movement of the pulsating elements is possible, lateral 
movement of rods 26 within the holes are minimized, thus reducing 
secondary noise vibration. 
Rods 26 can be made from any suitable material which can withstand the 
temperature, pressure and vibrational conditions of the specific molding 
process into which the novel vibrating wall assembly is being 
incorporated. Any such suitable material known to those skilled in the art 
can be employed. The preferred composition of rods 26 will depend, in 
part, upon the specific deformable material passing over the vibrating 
wall assembly and specific molding process conditions being employed. 
As stated earlier, in the embodiment illustrated in FIGS. 3, 5-8 and 11 of 
the present invention, the specific linking means employed also comprises 
radially-oriented coiled wire springs 28. In the embodiment illustrated 
therein, one of the functions of spring 28 is to interconnect 
radially-adjacent surface elements. 
Specifically, as can be seen in FIGS. 3 and 6, spring 28 is dimensioned to 
fit into a notch or groove 32 defined in the side wall 34 of at least two 
radially-adjacent surface elements. Notch 32 is positioned along surface 
element side wall 34 such that it is aligned with similar notches defined 
in radially-adjacent surface elements. 
It should be noted, however, that it is within the scope of this invention 
for spring 28 to be fitted not only in notches defined in 
radially-adjacent surface elements, but also in corresponding notches 
defined in longitudinally-adjacent surface elements, FIG. 15 illustrates 
an embodiment of the invention wherein the biasing means and the linking 
means is a single unit. For example, spring 28 protrudes beyond surface 
element side wall 34, a corresponding receiving notch can be located in 
the surface element side wall which abuts against side wall 34. In this 
latter embodiment, spring 28' would be useful for interconnecting 
radially-adjacent surface elements, as well as longitudinally-adjacent 
surface elements. 
The vibrating wall assembly of the present invention also comprises a 
biasing means for returning a pulsating surface element from its energized 
position back to its original resting position. In the embodiment 
illustrated in FIGS. 3, 5-8 and 11, spring 28 is the specific biasing 
means employed. 
Specifically, in these Figures, spring 28 has two major functions. These 
are as follows: (a) linking together radially-adjacent surface elements to 
create a chain of continuity among their respective motion, and (b) 
returning the pulsating surface elements back to their original resting 
position after being energized. 
Spring 28 can be made from any suitable material which can withstand the 
temperature, pressure and vibrational conditions of the specific molding 
process into which the vibrating wall assembly is being incorporated. 
Moreover, if spring 28 is doubling as the biasing means, it must also have 
associated therewith a degree of resiliency, such that it can return the 
pulsating surface element(s) from their energized position back to their 
original resting position. 
Any such suitable material known to those skilled in the art can be 
employed. The preferred composition of spring 28 will depend, in part, 
upon the specific deformable material passing over the vibrating wall 
assembly, the specific molding process conditions being employed and the 
specific energizing means being employed. 
Referring now to FIG. 4, this is a side planar view of a cylindrical 
vibrating wall assembly made from a plurality of surface elements in 
accordance with the present invention. These surface elements are radially 
interconnected by springs 28 and longitudinally interconnected by rods 26 
(see, for example, FIGS. 5 and 6). The important thing to note about FIG. 
4 is that it demonstrates that the width of surface elements 22 can vary 
according to a predetermined configuration. This can enable the user to 
control certain rheological properties of the deformable material passing 
over the vibrating wall assembly. 
Moreover, it is also within the scope of this invention to vary the radial 
length of the individual surface elements (see, for example, FIG. 11). 
Here, special care needs to be taken such that the corresponding openings 
in longitudinally-adjacent surface elements, line-up in a manner which 
permits the longitudinally-oriented linking means to pass therethrough. In 
FIG. 11, this problem is solved by employing elliptically-shaped openings 
30'. 
While the vibrating wall assembly illustrated in FIGS. 4, 5, 7, 8 and 11 is 
cylindrical, it should be noted that the present invention can be applied 
to form a vibrating surface having any geometric configuration. For 
example, the surface elements of the present invention can be employed to 
form vibrating wall structures having any of the following configurations: 
flat, concave, convex, multifaceted, rectangular, square, triangular, 
polyhedronal, elliptical, etc., and the like. 
Moreover, in FIGS. 4, 5, 7, 8 and 11, the collective inner wall surfaces 24 
and outer wall surface 22 of the individual surface elements making up the 
vibrating wall assembly have the same configuration (i.e., circular). 
However, when practicing the present invention, these wall surfaces need 
not be identical. For example, it is within the scope of this invention 
for the outer wall of a particular surface element to be concave, while 
its opposing inner wall is convex. 
What follows is a detailed explanation of one specific embodiment of the 
present invention wherein the vibrating wall assembly is incorporated as 
an integral part of a pipe extrusion apparatus. It should be noted, 
however, that the scope of this invention goes far beyond the extrusion of 
pipes and the following specific example. 
In practice, the individual surface elements are fitted together such that 
their collective upper or lower surface define a specific design and/or 
geometric configuration. In the specific embodiment illustrated in FIGS. 7 
and 8, the plurality of surface elements are interconnected to define a 
cylindrical vibrating wall assembly which is incorporated in an extrusion 
die apparatus. 
Referring now to FIG. 7, this is a side, partially sectionalized view of an 
extrusion die generally referred to as item 40. Extrusion die 40 comprises 
a cooling jacket 42 and a vibrating wall assembly generally referred to as 
item 44. The deformable material being molded by extrusion die 40 will 
pass through the gap 46 defined between cooling jacket inside wall surface 
48 and vibrating wall assembly outside wall surface 50. 
Vibrating wall assembly 44 comprises a plurality of pulsating surface 
elements 20, linking rods 26 and biasing springs 28. The specific 
energizing means employed in this embodiment comprises a series of 
longitudinally-oriented push rods 52, energizing drive shaft 54, drive 
shaft cage 56 and tapered drive wheel 58. 
In practice, the outside wall surface 60 of push rods 52 pushes against the 
inside wall surface 24 of the individual surface elements 20. This 
energizes the particular surface elements and results with their upper 
wall 22 moving towards the cooling jacket inside wall surface 48. This 
also puts an outwardly-oriented strain on springs 28. 
Push rods 52 are moved around the vibrating wall assembly inside wall 
surface 55 by cage 56 which is connected to energizing drive shaft 54. In 
the particular embodiment illustrated in FIGS. 7 and 8, the rotation of 
push rods 52 is due, in part, to the friction between push rod's upstream 
tapered end 62 and corresponding tapered drive wheel 58; and the friction 
between push rod downstream tapered end 64 and corresponding drive shaft 
downstream tapered end 66. 
In practice as the outside wall surface 60 of push rods 52 ride against the 
inside wall surface 55 of vibrating wall assembly 44, an 
outwardly-oriented pressure is exerted onto the individual pulsating 
surface elements 20. This energizes the surface element such that it 
slightly closes the gap 46 between vibrating wall assembly outside wall 
surface 50 and cooling jacket inside wall surface 48. This, also places a 
strain on biasing springs 28. 
After push rods 52 pass over a particular set of pulsating surface 
elements, biasing springs 28 relieves the strain imparted thereto by 
returning the energized surface elements back to their original starting 
position. 
The frequency at which the pulsating surface elements move from their 
resting position to their energizing position depends, in part, on the 
speed of drive shaft 54 and the number of push rods 52. 
Since the basic concept behind an extrusion die is the passing of a 
deformable material through a gap, when practicing the present invention 
illustrated in FIGS. 7 and 8, it is important to maintain an open gap 
between vibrating wall assembly outside wall surface 50 and cooling jacket 
inside wall surface 48. Accordingly, vibrating wall assembly 44 comprises 
a means for limiting the maximum displacement amplitude for the individual 
surface elements. This limiting means is rod 26. Specifically, the 
clearance between opening 30 and rod 26 determines the maximum 
displacement amplitude for the individual surface elements 20. Therefore, 
by making this clearance less than the width of gap 46, gap 46 will remain 
open throughout the pulsating cycle of the surface elements. 
In the embodiment illustrated in FIGS. 7 and 8, the amplitude of pulsation 
can be controlled by adjusting the length of energizing drive shaft 54. 
For example, by shortening the distance between drive shaft tapered end 66 
and tapered drive wheel 58, push rods 52 are forced in an outwardly 
direction. This, in turn, increases the amplitude of displacement when 
push rods 52 roll past the individual pulsating surface element 20. 
Since push rods 52 work off the concept of friction, and since they are an 
integral part of extrusion die apparatus 40, large amounts of heat can 
build up within the interior-portion of vibrating wall assembly 44. In 
order to increase the usable life of this vibrating wall assembly, it is 
desirable to decrease the amount of heat being built up therein. This may 
be achieved by any suitable means known to those skilled in the art. 
Examples of such suitable means include, but are not limited to, blowing 
pressurized air through drive shaft 54 and/or circulating cooling fluids 
through push rods 52. 
FIGS. 9 and 10 of the present invention illustrate two, different 
embodiments of push rod designs. For example, FIG. 9 illustrates a side, 
partially-sectionalized view of push rod 52 also illustrated in FIGS. 7 
and 8. As can be seen push rod 52 comprises a tapered upstream end 62, a 
cylindrical body portion 63 and a tapered downstream end 64. 
FIG. 10, on the other hand, illustrates a push rod 52' which comprises 
tapered upstream end 62', tapered downstream end 64' and body portion 63'. 
As can be seen by comparing FIGS. 9 and 10, the body portion 63' of push 
rod 52' is highly irregular while that of push rod 52 is virtually smooth. 
Accordingly, when a push rod similar to that illustrated in FIG. 10 is 
employed, only certain sections of the pulsating surface elements will be 
energized when the push rod rolls thereover. This will create a different 
vibrational pattern and thus a different flow pattern. 
As stated earlier, it is also within the scope of this invention to have 
the individual pulsating surface elements constituting the vibrating wall 
assembly to be energized by electromagnetic, ultrasonic or other 
mechanical means. Such a process would allow for the individual 
programming of amplitude and frequency of vibration and temperature 
associated with each individual pulsating surface element. While such a 
process eliminates the system of motors and push rods as illustrated in 
FIGS. 7 and 8, it requires the management of a great deal of coordinated 
sensors. It should be noted that the breakdown of a wall surface into a 
series of small surfaces greatly reduces the energy requirements for 
energizing systems. It is an important feature of the present invention to 
have been able to decrease the amount of energy required to vibrate a full 
body, irrespective of its size, by dividing area of force into small 
zones. 
In another embodiment of the present invention, the novel vibrating wall 
assembly is disk-shaped (not shown). Here, the vibrating wall assembly 
would be made up from a plurality of concentric surface elements. These 
can be energized by any suitable means known to those skilled in the art. 
For example, one method of energizing such a disk-shaped vibrating wall 
assembly is by rotating thereunder push rods which emerge from the center 
of the disk assembly and move outwardly toward the disk's periphery. 
The vibrating wall assembly of the present invention can also be employed 
in a system which transports and/or treats extruded plastic pipes coming 
out from an extrusion die. As demonstrated above, the frequency and 
amplitude at which the individual surface elements pulsate can be 
programmed, thus creating the effect of a vibrating wall over which the 
extruded plastic pipes will pass as they are being cooled. 
The novel vibrating wall assembly of the present invention can also be 
employed to transport liquid-pasty and/or liquid-rubbery matter along 
distances inside annular or slit dies. By employing the vibrating wall 
assembly of the present invention, the normal amount of friction 
encountered at the interface between the outside wall surface of the 
vibrating wall assembly and the flowing plastic material can be 
drastically reduced. Moreover, the vibrating effect of the novel wall 
assembly also provides an advantage in that it subjects the flowing 
material to a rheological treatment as disclosed in U.S. Pat. No. 
4,469,649. 
The modifications of the material's physical properties, due to the 
vibration levels to which it is subjected via the novel vibrating wall 
assembly, can be beneficially used to increase the material's 
processability. For example, when the material's yield strength at the 
corresponding temperature, for the given state of vibration, is greater 
than zero, but still sufficiently low enough to accommodate the amount of 
force provided by the local displacement of the pulsating surface 
elements, cold drawing is performed on the material. This results in a 
great deal of strain hardening due to orientation in several directions. 
Here, the part submitted to a longitudinal motion along the vibrating wall 
assembly is, therefore, transversely hammered by the pulsating surface 
elements which act like small pins calendaring the material to create 
improved conditions of orientation by the plastic yielding process. 
Referring now to FIG. 12, an embodiment is illustrated wherein the 
vibrating wall assembly of the present invention is incorporated in an 
apparatus which produces rheologically treated extruded pipes. 
The system illustrated in FIG. 12 comprises three general parts. These are 
as follows: pipe cross head die generally referred to as 70, 
preconditioning barrel generally referred to as 72, and rheological 
cooling unit generally referred to as 74. Rheological cooling unit 74 
comprises a vibrating wall assembly similar to that illustrated in FIGS. 7 
and 8 described earlier. 
The cross head die 70 and flow divider provide a source of a deformable 
plastic material flowing in a direction which is perpendicular to the 
extruder alignment. This configuration allows room for the insertion of 
long concentric shafts rotated independently with motors 80 and 82. Motor 
80 is for rotating the drive shaft associated with preconditioning barrel 
72, while motor 82 is for rotating the energizing drive shaft associated 
with the rheological cooling unit 74. 
After passing through cross head die 70, the deformable plastic material 
passes through preconditioning barrel 72. As the deformable plastic 
material passes through preconditioning barrel 72, its thermal and/or 
mechanical history is altered to a predetermined level. 
Any suitable preconditioning means can be employed in this particular 
embodiment. One example of such a suitable preconditioning process is 
described in U.S. Pat. No. 4,919,870 which, as stated earlier, is 
incorporated herein by reference. By employing a preconditioning system 
encompassed by U.S. Pat. No. 4,919,870 as the preconditioning barrel of 
this particular embodiment, one is able to control the amplitude and 
frequency of vibration in successive zones which are maintained at a given 
temperature as the deformable plastic material flows through barrel 72. 
It is also within the scope of this invention for preconditioning barrel 72 
to comprise temperature control zones, which are submitted to vibration 
with a set of eccentric masses rotated from the inside of barrel 72. This 
vibration is, in turn, communicated to the deformable plastic material 
passing through the annular clearance defined therein. 
In practice, the temperature of the outside jacket in preconditioning 
barrel 72 is often regulated. This allows the programming of a specific 
temperature for a particular zone therein. If desired, the temperature 
regulation of preconditioning barrel 72 can be controlled by implementing 
a series of thermocouples which are connected to controller and commanded 
by being interfaced with a computer system and for a specific software 
design. Moreover, it is also possible to regulate the pressure exerted on 
the flowing material by controlling the amplitude of vibration in each 
zone through the specific displacement of vibrating surface elements. 
In the particular embodiment illustrated in FIG. 12, the drive shaft 
associated with preconditioning barrel 72 rotates eccentric masses at a 
predetermined frequency. This dictates the amount of vibrational energy 
dissipated to the deformable plastic material passing through 
preconditioning barrel 72. 
It should be noted that preconditioning barrel 72 need not subject a 
mechanical vibration to the deformable plastic material passing 
therethrough. Rather, preconditioning barrel can be a means for subjecting 
the deformable plastic material passing therethrough to only temperature 
conditioning. Moreover, preconditioning barrel 72 can also comprise a 
vibrating wall assembly similar to that disclosed in FIGS. 7 and 8. Here, 
it is preferred for the vibrating wall assembly to have a coating material 
or layer (e.g., a film) thereover to minimize the flow of material between 
the joints of adjacent surface elements. 
It is also within the scope of this invention to have the frequency and 
amplitude of vibration, in addition to the amount of pressure applied by 
the extruder, programmed according to the disclosure in U.S. Pat. No. 
4,469,649 which, as stated earlier, is incorporated herein by reference. 
After passing through preconditioning barrel 72, the now preconditioned, 
deformable plastic material passes through rheological cooling unit 74. As 
stated earlier this unit comprises a vibrating wall assembly similar to 
that illustrated in FIGS. 7 and 8. It should be noted, however, that any 
vibrating wall assembly encompassed by this invention can be employed 
herein. The use of the described extrusion process can aid in the 
production of highly oriented sheets, tubes, rods, etc. by shear yielding 
resulting from the vibrating surface elements. 
As can be seen from the foregoing, by practicing the present invention, the 
physical properties of a molded product can be controlled and/or altered. 
Specifically, by passing a deformable material over the vibrating wall 
assembly of the present invention, the shear stress within the molded 
product can be controlled and/or altered. Moreover, the implementation of 
the present invention to a sheet die apparatus having a flat surface 
rheological cooling unit made up of a vibrating wall assembly as described 
herein is also encompassed by the present invention. 
As also can be seen from the foregoing, if the novel vibrating wall 
assembly disclosed herein defines at least one surface of a mold or die 
geometric configuration, it can eliminate at least some of the presence of 
"rivers" resulting within the molded product. This will, in turn, minimize 
the degree of shrinkage during the solidification stage. 
It is evident from the foregoing that various modifications can be made to 
embodiments of this invention without departing from the spirit and scope 
thereof, which will be apparent to those skilled in the art. Thus having 
described the invention, it is claimed as follows.