Note: Descriptions are shown in the official language in which they were submitted.
216000D
BACKGROUND OF THE INVENTION
This is a U.S. national stage patent application based on International
Patent Application PCT/EP94/01043, filed on April 3, 1994 and claiming
5 priority dates of April 6, 1993 (filing date of German patent DE 43-11978-C1)
and January 25, 1994 (filing date of German patent DE 44-01974-A1).
1. FIELD OF THE INVENTION
The present invention discloses method and apparatus for a dent
stiffening process for sheet material or foil in which the wall is curved at
regular distances.
2. BACKGROUND ART
For economic and material reduction purposes thin-walled equipment
or components are required in numerous technical applications which
nevertheless have to have good strength, or shape stability. As these
equipment are often component parts utilized in energy in energy and
20 environmental related applications, the walls should ideally have favorable
inflow and heat-transmission properties. For weight and economic reasons,
thin-walled and dimensionally stable constructions are also required in the
packaging, design, interior fittings and building trades. In addition to
structural rigidity, foil or thin-walled equipment should also have good
2 S optical features.
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There are numerous known deformation processes which produce
thin-walled materials with an increased structural rigidity. A well-known
example is the beaded seam in cans or drums. Beads have the disadvantage
that they only achieve a one-dimensional structural rigidity. When a multi-
5 dimensional structural rigidity is required, the process requires sophisticatedmulti- dimensional matrix molds.
One drawback of the present profiling technology is that normally the
wall deformation is achieved by mechanical means, where rolling or
10 impressing is applied, or by hydraulic means, where pressure is put on a
matrix. This alters the wall thickness while the original smooth wall surface
quality is degraded. Only when the mold has a smooth surface, which
normally means that its manufacture was very sophisticated, can a smooth
surface of the deformed wall be achieved.
It is known from published German patent application # DE-OS 25 57
215 that there is a hydraulic molding technology in which thin-walled tubes or
cylindrical containers obtain a uniformly staggered dent structure. According
to that patent, the interior cylindrical walls are supported by thrust rings or a
20 helix and then excess pressure is externally applied to achieve the dent
deformation. In this type of hydraulic profiling technology, which is quasi-
exempt from mechanical contact, a high quality surface finish is achieved. The
uniformly staggered dent structure of the tube walls results in an increase in
the rigidity compared to the non-deformed smooth wall.
This hydraulic dent profiling process does, however, have considerable
disadvantages. As this process is limited to tube and cylinder walls, it is not
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possible to produce large dent-profiled sheet metal or foil with variable,
geometric dimensions in the dented structure. Another disadvantage of this
dent profiling process is that in order to bend sheet metal into a cylindrical
form with perfect roundness, the two-cylinder rounding machining, which is
5 the best known method, is used. (In this method, sheet metal is rolled over a
rigid roller, which presses on a flexible bottom roller. This method is
described in, for example, German patent nos. 1602489, 1752001 and 1552017.)
This well-known and old twin-cylinder rounding method is more suitable for
the production of cylindrical building components requiring no structured
10 walls. When structured and cylindrical components are to be manufactured by
the twin-cylinder rounding method, the structured molds are expensive and
the surface quality of the raw materials is severely degraded due to the strong
mechanical deformation process.
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SUMMARY OF THE INVENTION
According to the present invention, thin sheet metal and foil with
5 multi-dimensional staggered dent structures can be manufactured by simple
mechanical devices, producing material that can be used in a variety of
industrial applications. Improved multi-dimensional structural rigidity in
dent-profiled components is achieved.
The problem is solved in that the sheet metal, which is arched over the
regularly spaced supporting elements, is successively dent-profiled. The
pressure needed to cause dent formation (active dent pressure) should be
lower than the defensive rigidity of the fold of every dent formed
spontaneously. The direction of the dent profiling is parallel to the support
1 5 elements.
Dent profiling is hydraulically achieved with a fluid pressure medium,
or pneumatically with a gaseous pressure medium, or by means of an elastic,
or flexible or otherwise compact pressure medium. The successive sequence
20 of the dent profiling is achieved by a continuous or gradual (segment-wise)
machining operation. When pressure is applied with liquid or gaseous
pressure mediums, a sealing on the edge of the respective formed surface is
applied. The buckling pressure can be applied as excess pressure or
underpressure. Various buckling pressure applications can be combined.
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The regularly spaced support elements are ideally in the form of a rigid
or flexible helix, rings, discs or other elements with serpentine or continuous
zigzag patterns in the peripheral direction.
One of the advantages gained through the present invention is that
thin walls or foil can be dent-profiled in a semi-continuous or continuous
manufacturing process, so that in this way large surfaced and endless material
sheets with enhanced multi-dimensional rigidity can be produced, despite
thin walls. No expensive stamping molds are required for this manufacturing
10 process. The advantages result from the following principal:
When support elements, e.g. regularly spaced support rings or support
helixes are used to dent-profile cylindrical cylinders or coiled sheet metal, orfoil, whereby a co-axial external excess pressure and/or internal
15 underpressure is applied, the structure of the dent independently repeats
itself over the entire surface of the cylinder wall. Research of segment-like
dent profiling operations has confirmed that in order to achieve uniform and
staggered dents, the entire cylinder circumference does not have to be formed
simultaneously. The invention provides for only individual segments to be
20 successively dented in the peripheral direction. However, the individual
segment pressurized can comprise two or more individual dents in the
peripheral direction.
The advantages of the present invention are achieved in that the sheet
25 material to be structured is arched over a segment of the support roller, on
which regularly spaced support elements are placed, then successively
pressed, segment for segment, by externally applied excess pressure. This
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results in a considerable increase in the productivity of the dent profiling
process.
It is important to differentiate this method from the so-called deep-
5 draw method, whereby the material is deformed and flows. In the deep-draw
method, the surface size is considerably increased as a result of the drawing
process. With the present invention, there is hardly any alteration to the
surface size. Buckling can occur, when the buckling pressure is sufficient to
cause an indentation. In addition, the pressure must be too low to indent the
10 relatively rigid edge of the dents that are spontaneously formed in feed
direction. The dent edge resists the deformation. By applying further feed
motion the denting pressure finds an area in the surface with a low
resistance. A new dent emerges with an identical resistant edge. The
previously described process repeats itself. Accordingly new dents are
15 successively formed. As a result, the invention requires no support to form
dent edges in the feed direction, i.e. a series of uniformly distributed dents
spontaneously appear on the curved material. The dents are formed on the
thin wall segment and are in a staggered position to those dents formed in the
initial indentation process. A honeycomb structure emerges with a relatively
20 high transverse strength in every direction. When regularly spaced rings or
helix are used as support elements staggered quadrangular dents occur. The
dent size depends on the diameter of the support roller and the axial spacing
distance of the support elements.
2 5 The depth of the dent in the elastic denting process is self-regulating
and depends largely on the width of the dent and curvature radius of the
regularly spaced support elements during the denting process. The depth of
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the dent can further be increased when the deformation temperature is
boosted into the elastic/plastic transition region during the process, e.g. by
heating up the material sheet to be processed. This boosting of the
temperature can be achieved by applying a pressure medium or, in the case of
5 metallic material sheets, by means of electric currents.
Another advantage of the invention is that because of the regularly
spaced support elements, which may have a serpentine or zigzag form in the
peripheral direction, hexagonal or pentagonal shaped structures can be
10 manufactured on the dented thin-walled material. These multi-cornered
structures have the advantage over quadrangled structures in that, for
symmetrical reasons, a practically identical structural rigidity in all directions
is achieved. Experimental studies have confirmed that these multi-cornered
structures are preferentially formed during the dent process. When flexible
15 and regularly spaced support elements are used, which can be shifted in an
axial direction, the flexible supports independently form zigzags.
This shifting is caused by the tensile stress and compressive stress areas
in the dented wall which attempt to equalize themselves. The shape of the
20 hexagonal or pentagonal dent structure is related to the following parameters:
flexibility of the supporting elements, dent pressure and the deformation
capacities of the various materials used.
For geometrical reasons hexagonally shaped dent structures are formed
25 when cylindrical supports or a support roller with zigzag revolving support
elements are used. In contrast preferentially pentagonal or hexagonal dent
structures are formed when the support roller has a spherical or shell shape.
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It is known, for example, that for geometric reasons a spherical surface cannot
be built up of equal-sized hexagonals.
In accordance with the invention flexible support elements, preferably
5 bands or rings made of elastomers, plastic, metal as well as linkages (chains) or even helix which have a circular, oval, quadrangular, triangular or
trapezoidal cross-sectional area are used. In order for the flexible supports tomove axially on the support roller on the one hand, and on the other hand to
be held in place at regular intervals, the invention allows for highly elastic
10 sleeves, i.e. made from elastomer, soft plastics or metallic cloth to be mounted
axially and placed between the supports. Alternatively the support elements
can also be held in place by revolving, flat grooves in the cylinder roller.
Additional application methods are also possible.
In a further favorable design, the regularly spaced flexible or rigid rings
or helix, which are affixed to the support roller, are used as support elements.Flexible discs, which are inserted into the support roller at regular intervals,can also be used as support elements.
The dent deformation with flexible support elements can result in an
irregular zigzag pattern, so that the hexagonal structures are not uniform.
Furthermore, elastic support elements compress slightly during the dent
deformation process. When this is not desired the invention allows for rigid
or only slightly flexible support elements to be used which have a defined
2 5 zigzag or serpentine form. In this way, defined, reproducible hexagonal
structures can be achieved during the dent deformation process. Due to the
invention, preference should be given to those zigzag and serpentine forms
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in the support elements which ideally independently would adjust
themselves to the elastic support elements.
The special advantages gained from the invention also means that the
5 dent deformation of thin walls is no longer limited to the piece-wise
manufacturing of cylindrical walls. As only one segment of the support roller
is required for the successive dent deformation of the sheet material, the
invention allows for semi-continuous or continuous dent deformations for
the manufacture of quasi non-intermittent foil or strips. The productivity of
10 the dent-profiling process can be greatly increased.
In accordance with the invention a "quasi" non-intermittent
manufacture of dent-profiled strips can be achieved in that sheet metal or foil
is transported over a support roller to which revolving support rings or helix
15 are attached, and then dented by means of pressure from an exterior flexible
pressure collar. This process is progressive. When the pressure collar is
unpressurized the sheet material is advanced to a new segment. When the
new segment of the sheet material is in place, the dent structures are then
hydraulically impressed by the pressurizing of the pressure collar.
According to the invention, the pressure collar may also have a
structural surface which will be complementary to the resulting profile of the
sheet material. The pressure collar is preferably made of an elastic material.
Although this is a mechanical rather than a hydraulic production process, it is
25 not comparable to the traditional compression molding process, where the
material is pressed into form in a plastic state. This is not the case in the
invention. Here the mechanical indentations are formed through a denting
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process which derives from a curvature of the strips, the support rings, the
support helix on the inside of the strip, as well as a specially dent-profiled
shape of the surface of the pressure collar. The dented surface of the pressure
collar should ideally have a structure which independently results in an
5 image reflected structure when hydraulic dent profiling takes place. The
surface created in this way has the effect as if numerous, separate hydraulic
pressure elements are utilized according to the dent-profile regularities
described above.
Another advantage of the invention provides for a continuously
working mechanical dent process. Instead of a pressure collar with a dent
profile-like structure, a flexible profile band is applied which has tightly
spaced supporting rollers on one side and staggered knobs, preferably made of
ebonite, on the other side. The staggered knobs are affixed in such a way that
5 they correspond to the dent indentations of the resulting dented structure.
The industrial costs for a continuous denting process can be decreased
further in that in accordance with the invention, flexible pressure rollers or
pneumatic rollers are used for the dent-profiling process. Hereby the material
20 sheet to be formed, which is curved over the support roller, which in turn
has supporting elements placed at regular intervals, is pressed by the pressure
roller. The flexible pressure roller comprises an elastic cylindrical pressure
jacket, preferably made of an elastomeric material. The pressing power can be
controlled or regulated.
In accordance with the invention, a flexible or pneumatic, profiled,
preferably knobbed pressure roller can also be used, whereby the staggered
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knobs correspond to the dent indentations of the dented material. The
advantage is that the pressure roller simultaneously presses a segment, with
two or more dents, into the material sheet in the circumferential direction.
Furthermore, rigid pressure rollers with staggered, rigid or flexible
knobs can be implemented. This is preferable for dent profiling of thick sheet
metal or bands which require comparably high deformation pressure.
Although the knobs press on the material sheets, it does principally represent
a dent profiling process. However, the surface of the material to be deformed
10 is degraded by the pressure of the rigid, knobbed pressure roller compared tothe case in a flexible or pneumatic pressure roller. The buckling pressure
required is reduced when, according to the invention, the dent profiling of
the material is carried out at an increased temperature.
The dent deformation by means of staggered knobs has, compared to
hydraulic dent deformation, the advantage that the geometrical form of the
dent structure can be variably adjusted. The support rollers can be used with
flexible or rigid support elements.
A further advantage of the invention is the application of two or more
pressure rollers. For example, the first pressure roller, equipped with rigid
knobs, produces rough dent structures, while the following, flexible pressure
rollers form the required dent troughs and equalize any unevenness that
might occur in the bulge troughs. A reversed sequence of the pressure rollers
also has advantages. According to the invention, zigzag shaped, serpentine
shaped or other periodically revolving support elements can be used for the
dent profiling process. Only minimal deformation of the support elements
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occurs as they are adjusted to the rotation line of the multi-dimensional
staggered dent structures.
Another advantage of the invention's design concerns the
5 manufacture of pipes, especially pipes made from extrusion or extendible
(plastic) or rolled or drawn (metal). The indentation in the plastic is only
permanent when it surpasses the restoration capabilities of the material. This
applies to all materials.
Single or multiple helical support elements can be used, which
synchronously rotate with the axial transport speed of the pipes to be
deformed. To generate the dent pressure, one or more flexible, smooth or
profiled pressure rollers can be used, which move in the circumferential
direction of the pipe to be dented. The pressure rollers have the same
15 function as the previously described dent profile of the material sheets.
However, when profiled pressure rollers are used, the staggered knobs of the
dent trough have to be adjusted to the single or multiple helical support
elements. The knob shape does not have to be exactly identical to the dent
made in the pipe. It suffices when the knobs only reflect the suggestion of the
20 contour of the dent and a sort of nucleation/initial effect during the
formation of the dent. This process is also suitable for dent deformation of
continuous pipes. As the dent-profiled pipes have an increased radial rigidity
and an improved flexibility as opposed to smooth (non-dented) pipes they can
be coiled up as continuous pipes.
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Alternatively, according to invention, the pipes to be processed can be
axially turned and transported so that the rotating pressure rollers can be
permanently fixed.
A further favorable design feature of the invention allows for
continuous pipes to be dent-profiled. A flexible pressure collar is fixed to theexterior of the pipe and a helix fixed to the inside the pipe. They rotate
synchronously with the axial transport speed of the pipe. After the dent
deformation has occurred, pressure is released from pressure and collar
10 pulled back, and the helix is moved back to its original position by means of an axial turn. In order to ensure that during this discontinuous dent
deformation process uniformly shaped dents occur along the length of the
continuous pipes, the invention allows for the denting process to overlap
partially so that existing dents act as a nucleus for new dent deformations.
15 Furthermore, a pressure gradient, counter-clockwise to the axial transport
direction, is utilized. This pressure gradient is produced in the pressure collar
by a compressible medium (e.g. air) or a fluid which flows through porous,
flexible materials or plates. Alternatively viscous pastes or gels are used. After
the dent deformation process, the pressure is released from pressure collar.
Another invention feature is that a helix can also be used as a support
element whose external circumference can be varied through a mechanical or
pneumatical device. In this way, the helix can be returned to its original
starting position with minimal force after every dent deformation.
A choice is given in the invention that material sheets, foil or shell-
shaped containers can be dent-profiled in such a way that truncated cones,
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dent structured semi-finished products or components are produced.
Truncated cone products such as buckets, transport boxes (containers) or
beakers have the advantage that they can be economically stacked into each
other. Truncated cone components should, for rigidity and optical reasons,
5 have the same number of dents in the circumferential direction, regardless of
the variable diameters. A feature of the invention is that parameters can be
altered, spacing h of the support helix or rings and wall thickness. When
hydraulic pressure is applied, the same number of dents are formed in the
circumferential direction, despite differing diameters, by varying the spacing
10 between support elements or wall thickness. Alternatively, according to the
invention, truncated pressure rollers are used for the dent deformation
process. The local pressure for the dent deformation can be altered by means
of a variable angular indication between the pressure roller and the roller
with the support elements. Flexible or pneumatic smooth or knobbed
15 pressure rollers can be used to produce truncated work material.
According to the invention, any rotationally symmetrical component
can also be deformed by using elastic, pneumatic and/or profiled pressure
rollers. It is necessary that dent pressure be varied over the length of the work
20 piece by adjusting the pressure rollers so that, despite changed diameters, the
same number of dents occur in the peripheral direction.
Another design advantage allows for calotte shell or ellipsoid, thin
walls or foil to be dented. Examples here are spherical containers, dome-
25 shaped bottoms for cylindrical containers or ellipsoid shells, which, despitehaving thin walls, have a high rigidity. In accordance with the invention,
either a dense sphere packing or a case shell are used as support elements,
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which are externally supported by regularly spaced spheres, semi-spheres or
other round support elements. The dent structure of the spherical, thin walls
or foil to be formed occurs independently either through external excess
pressure or internal underpressure, whereby hexagonal and pentagonal dent
5 structures appear.
The dent-profiled thin material sheets or foil possess an increased
rigidity when an apex load (applied radially lengthwise along the cylinder) or
punctual load (applied radially) is applied. A dent-profiled cylinder made
10 from sheet aluminum is, for example, about 8 times more rigid than a
cylinder made from smooth aluminum, thus a 50% saving in weight and
material is achieved. This allows for numerous industrial application
possibilities for material and weight saving lightweight constructions.
Furthermore, as the dent-profiled foil retains its uniform dent
structure despite numerous indentations, the foil can be used for casings and
packaging. Dent-profiled thin walls and foil are suitable for encasing heat
insulators. For example, glasswool, as the insulating material can be fixed to
the indentations in the dent structures, thus there is no need for additional
20 fixtures or holding devices. The encasings for insulating materials are
dimensionally rigid, have a good optical appearance and save material. As a
result of the dent profiling process, the surface area quality compared to the
flat walls is hardly altered. This also applies to the highly reflexive surface of
anodized aluminum reflectors.
A feature of the invention is the application of dent-profiled material
sheets in light technology applications. A geometrically directed light reflector
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which creates diffused light is achieved when concave shells with convexed
dent structures are used. A concave shell with concaved dent structures
produces a directed, point-focal light scatter. Convex shells with convex dent
structures produce an almost uniform diffuse light scatter.
Another design enables dent-profiled material sheets to be used as
inherently rigid sound reflectors, whose geometric dimensions lie in the
region of the sound wavelengths to be reflected. In order to achieve constant
acoustic sound distribution in music halls, theaters etc. convex sheets are
10 normally used as sound reflection. Dent-profiled thin walls are very suitableas suspended sonic elements because of their rigidity. In order to achieve a
good sound reflection a heavy wall area is normally required. Thin-walled
dented shells can be lined with another material in order to increase the
material mass.
Dent-profiled walls or shells can also be used to reduce or avoid
acoustic reverberation effects by diffusing the sound within the dent
structure. Comparatively deep dents are made whereby the geometrical size of
the dent more or less corresponds to the acoustic wavelengths of the air.
2 o Application areas: loud factory shop floors, transport halls etc., where the noise is diffused and absorbed in noise absorption units.
According to acoustic engineering laws, good loud speakers must have
a low mass and high flexural strength. Thin-walled plates and dish cavities
2 5 with dented profiles conform to these requirements because the ratio between flexural strength and mass is high.
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Another acoustic property of dent-profiled pipes or hollow cylinders is
that the acoustic fundamental mode is increased when a dent-profiled wall is
compared to a smooth wall with otherwise exact geometrical dimensions.
The following applications are possible: a loud speaker with a dent-profiled
5 thin wall has a larger geometrical diameter compared to a smooth wall and
consequently a larger resonance body when both the dent-profiled and
smooth sound bodies are to have the same acoustic fundamental mode. This
includes so-called plate oscillators which act as resonators and absorb the
sound by means of resilience on a posterior air cushion. On the other hand in
10 technical applications vibration-free pipes, cylinders or hollow tube blanks are
required which are not stimulated to oscillation in the lower frequency area.
An example is chimneys which, in order to avoid damage, should be rigid
but not subject to oscillation by the influence of wind. This danger can be
avoided by using dent-profiled pipes, cylinders and hollow bodies as the
15 lower stimulative oscillation frequency is increased compared to that
produced by smooth walls. Undesired booming (clanging) is therefore also
reduced.
Another design feature provides for dent-profiled material sheets to be
20 used for dimensionally rigid multi-chambered containers, where the internal
partition walls are affixed to the outer wall through the peripheral dent fold.
In recycling technology multi-chamber reservoirs or containers are used to
separate glass, cans, paper etc. When multi-chamber containers are
manufactured from dent-profiled walls they offer two advantages. The
25 containers have less weight because of their shape rigidity and the internal
partition walls, which are normally cylindrical, are attached to the outer wall
by the peripheral dent fold.
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A sandwich construction made up of layered dent-profiled walls or
shells, which also increases the shape rigidity, is another feature of the
invention.
In order to ensure equal distances between the layered dent-profiled
walls, the inner and outer walls are alternately profiled with either left- or
right and left-handed helixes. The twists of the helical support are either
single or multiple during the dent-profiling process. The free-flow cross
10 section between the dent-profiled walls can be enlarged by spacers if needed. They serve as flow channels for heat or material transfer in power
engineering or application technology apparatus. The heat or material
transfer is improved compared to smooth wall structures when flow is
diffused on the dent structures. Because of the extremely smooth surface
15 texture of the dent-profiled walls, the danger of solid matter particle deposits
(so-called fouling) is reduced. A simple and weight-saving construction for
heating or cooling plates is obtained when two walls are affixed to each other
on the dent-profiled side, i.e. through adhesion or soldering. Dent-profiled
thin walls which are affixed to smooth thin walls result in a rigid and
20 optically pleasing wall which can be used as exhibition stand walls or in
packaging applications. Sandwich constructions made up of perforated or
slotted dent-profiled walls, which are fixed together with spacers, are suitableas weight-saving, sound-absorbing components. An example is a car exhaust
which simultaneously has axial compensation properties when thermal
25 expansion occurs. Another favorable result of the invention occurs when
spiral-shaped coiled dent-profiled walls are slid into one another and separate
flow channels for spiral heat exchangers are formed. The installation is
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identical to the normal construction technology. However, the spiral walls
are dent-profiled which, despite having thin walls, have a high rigidity, low
mechanical vibration stimulation and improved convective heat transfer
properties.
In a similar manner spiral-shaped, coiled dent-profiled walls are
suitable for the manufacture of rotating heat exchangers, whereby the
regenerative method, e.g. the waste heat of a hot exhaust flow is transformed
to cold fresh air flow. Air flows through the gaps in the spiral shaped sheets
10 in an axial direction. Due to the staggered dent structures, a high convective
heat transfer results and the pressure loss is comparatively low.
Another advantage of the invention is that dent-profiled material
sheets, which preferably have a rough surface, can be used for top-blow (spray-
15 painting) shotcrete. Normally expensive fixtures made up of stiffenedmaterial are used to reinforce support concrete constructions which are
shotcreted. Dent-profiled walls and shells are better suited for spray painting
shotcrete because they are rigid and labour-saving. To ensure that the
shotcrete fully adheres to the dent-profiled walls good bonding properties
2 0 must be obtained. For example, a rough surface of mesh or wire grating is
attached to smooth walls. Before the dent-profiling takes place the mesh or
wire grating should ideally be affixed to the walls, either by adhesion or
soldering.
Composite structuring is another design feature resulting from the
invention. When the cavity space in a dent-profiled sandwich construction is
filled with a secondary material, dimensionally stable and rigid composite
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structures are the result. With cylindrical or shell-shaped composite
structures the undercut folds of the dent structures provide a good positive
locking effect between the dent-profiled walls and the secondary (filling)
material. The adhesion properties between the dent-profiled wall and filling
5 material can be improved when a dent-profiled wall is reinforced with mesh
or wire grating. Inferior recycled synthetics are suitable as filling materials.This material can either be compressed into the hollow space in a fluid form
or in a fluid/solid mixture. For example, heated plastic is spread over the
individual dent-profiled walls before being compressed into a composite
10 structure. The fillers are pressed into the cavities of the dented slit, preferably
with an agitated nozzle. Alternatively a fluid/solid mixture,(i.e plastic solid
mixture) is applied to the individual dent-profiled walls prior to being
compressed to a composite structure. These composite structures, when
enclosing non-rigid plastic, also have an acoustic absorption quality because
15 expansion and compression occurs during bending vibrations, so that the
oscillation energy of the plastic is converted into thermal energy. When dent-
profiled composite structures are axial loaded, axial folds buckle and the
composite structures are further compressed. This results in the dent-profiled
walls having a large absorbing deformation resistance. This is the reason why
20 dent-profiled pipes, spirals or sandwich packets are suitable as spacers, shock
and energy absorbers. The cavities between the dent-profiled walls can also be
partly or completely filled with energy absorbing material.
Yet another advantage of the invention is the coating of the dent-
25 profiled fold or dent groove. For use in the optical or light technology areas of
advertising, interior design etc. the honeycomb shaped dent profiles can be
highlighted for lighting purposes by manufacturing dent-profiled transparent
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thin walls which are covered with a light reflecting layer on one side. The
light reflecting layer on the apex of the dent fold or bottom of the groove can
be removed, e.g. through etching. This causes the dent-profiled walls in the
area of the dent fold or groove to become translucent.
One example in the area of advertising is illuminated letters made of
dent-profiled pipes. At night time, the light source within the pipe scatters
diffusely and shines through the translucent areas. During the day, the
illuminated letters reflect the daylight shining on to the exterior of the dent-
10 profiled walls. The honeycomb-shaped dent profiles can be coloured by
various methods, i.e. by transmitting coloured particles suspended in a fluid
flow so that the coloration of the transparent surface in the fold of the dent is
deeper. Consequently very subtle colour gradients can be achieved. This
follows from the flowing physical laws of mass transfer. Vacuum
15 metallization is also possible. Coarse colouring is achieved by color rollerswhich are rolled over the surface projections. A variable coloration can be
achieved by using a thermal color which changes color depending on
temperature. A varying temperature distribution along the dent profiles is
achieved when, for example, an electric current (Joule effect) flows through
20 the dent structure causing variable heat transfer. The heat transfer on the
dent profile influences the temperature distribution.
A further application feature occurs in the production of bottles, drink
containers etc. The most popular manufacturing processes are either the
2 5 extrusion method, i.e. for plastics, or blowing, i.e. for glass. Here the material,
in its plastic state, is pressed against an external form by means of interior
pressure. In order to equip the thin-walled bottles, drink containers etc. with
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weight and material saving rigid walls, profiled forms are usually given
preference. In the hydraulic process, widely known under the name trade
Hydroform, metallic hollow bodies, e.g. pipes, are pressed against an exterior
form with a comparably high internal pressure and plastically deformed. As
5 an existing alternative process, sheet metal is deformed by pressure between
two molds in the mechanical deformation method. The manufacture of the
forms required for this process is expensive. The invention allows for the
manufacture of dent-profiled forms, which are used in the following
applications methods:
1) Dent-profiled walls are lined on their exterior with dimensionally
stable materials, i.e. by smoothing out the surface with molten metals,
which have a lower melting point than the material used in the dent-
profiled walls. To guarantee a good solidification of the filling material,
it is advisable (as previously mentioned) to roughen the surface area.
When metal is poured in, heat expansion and therefore deformation of
the dent structure can occur. A better method is the sandwich
construction made up of dent-profiled walls, as the dent structures
support each other.
2) Dent-profiled sheet metal or foil can be used for the manufacture of
sand core used in casting practice. The cores with the described dent
profile are used to cast the dent-profiled forms.
25 3) In a similar method to that of the dent-profiled walls being spray-
painted with shotcrete, the dent-profiled forms can be spray-painted
with metal, which solidifies on the dent-profiled wall. The
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solidification heat, i.e. the negative fusion heat is dissipated by cooling
the forms.
4) When dent-profiled forms are required for extremely high pressureapplications in the blow-molding process, the rigid forms can be milled
out of high tensile metal. Dent-profiled models are electronically
scanned and used as the model for computer-controlled milling.
Further advantageous design features as a result of the invention are
described below. Various embodiments of the invention are described in the
attached drawings and described in more detail.
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BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a diagram of the invention.
Fig. 2 is a horizontal projection of a dent-profiled structure
manufactured on a device according to Fig.1.
Fig. 3 is a view of an uncoiled dent-profiled structure manufactured on
10 a device according to Fig. 1 used with a multiple helix.
Fig. 4 is a view of an uncoiled dent-profiled structure manufactured on
a device according to Fig. 1, using support rings.
Figs. 5,6,7,8, and 9 are cross-sections of the different types of flexible
support elements on a cylinder jacket.
Fig. 10 is a schematic cross-section of a device with elastic/supple
packing for the regular spacing of flexible support elements.
Fig. 11 is a schematic cross-section of a device with grooves in the jacket
for the regular spacing of flexible support elements.
Fig. 12 is a view of a dent-profiled structure manufactured on a device
25 with rigid support elements.
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Fig. 13 is a view of a dent-profiled structure manufactured on a device
with flexible support elements and low denting pressure.
Fig. 14 is a view of a dent-profiled structure manufactured on a device
5 with flexible support elements and high denting pressure.
Fig. 15 is a view of a dent-profiled structure manufactured on a device
with flexible support elements and leaning on the jacket.
Fig. 16 is a schematic cross-section of a device with regularly spaced
flexible support discs on the jacket.
Fig. 17 is a schematic cross-section of another device with regularly
spaced flexible support discs on the jacket.
Fig. 18 is a schematic of a device with regularly spaced zigzag shaped
support elements on the jacket.
Fig. 19 is a schematic of a device with regularly spaced serpentine shaped
20 support elements on the jacket.
Fig. 20 is a view of a device with coiled and zigzag shaped support
elements on the jacket.
Fig. 21 is a view of a device with coiled and serpentine shaped support
elements on the jacket.
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Fig. 22 is a schematic of the knobs and the structure of a dent-profiled
band.
Fig. 23 is a schematic of the design of a device to manufacture dent-
5 profiled material sheets in a continuous denting process.
Fig. 24 is a schematic of the structure of a device to manufacture dent-
profiled material sheets with a flexible pressure roller and a ~acket studded
with support elements.
Fig. 25 is a view of a device with regularly spaced axial slits in the
flexible pressure roller.
Fig. 26 is a view of a device with regularly spaced axial and radial slits in
15 the flexible pressure roller.
Fig. 27 is a view of a device with regularly spaced helical-shaped slits in
the flexible pressure roller.
2 oFig. 28 is a schematic of the design of a device to manufacture dent-
profiled pipes with two external pressure rollers and an internal support helix.
Fig. 29 is a schematic of the design of a device to manufacture dent-
profiled pipes with an external pressure collar and internal support helix.
Fig. 30 is a schematic of the design of a device to manufacture cone-
shaped, dent-profiled components with two cone-shaped rollers.
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Fig. 31 is a schematic of the design of a device to manufacture spherical,
dent-profiled components.
Fig. 32 is a schematic of a device to manufacture calotte shell-shaped,
dent-profiled components.
Figs. 33, 34, 35, and 36 are schematics of a device to manufacture
different shell-shaped, dent-profiled components for diffuse light scatter.
Fig. 37 is a schematic cross-section of a multi-chamber container.
Fig. 38 is a schematic cross-section of a heating/cooling plate.
Fig. 39 is a schematic of a double-walled cylinder manufactured from
dent-profiled sheet material on a device depicted in Fig. 1.
Fig. 40 is a cross-section of the principle construction of a form with a
dent-profiled surface for the manufacture of containers according to extrusion
2 0 blowing technology.
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DETAILED DESCRIPllON OF THE INVENTION
Fig. 1 schematically depicts the semi-continuous dent-profiling process.
Sheet 1 is arched over the feed roller 2 and then over the support roller 3,
5 which is equipped with a support helix 4. By means of a flexible pressure
collar 5, which is supported by an external holding device 8, excess pressure ishydraulically applied to sheet 1 resulting in a denting process. The dent
profile is achieved by the impression caused by the excess pressure on the
thin-walled sheet 1. Indentations occur on the thin-walled sheet 1 between
10 the regularly spaced support elements of the support roller 3. Dents first
appear along the line of the support elements (helix 3) followed by
perpendicular folds that spontaneously form between the first folds. These
dent edges or dents folds cause a 3-dimensional dent stiffening. For this
reason the local dent remains rigid and the next dent appears. This
15 deformation process happens quickly. The special feature is that the dents
along the helical rows spontaneously stagger themselves so that the dent-
profiled thin walls receive high rigidity.
After the pressure is released from the pressure collar, the sheet is
2 0 advanced by turning the support roller 3 so that only a small area of the
previously dent-profiled sheet lies under the pressure collar 5. The dent
profiling follows on from this dented section. When required, the pressure
collar 5 can be built up into different pressure areas between outlet 6 and
intake 7. This can be achieved by separate pressure phases on the pressure
2 5 collar. Alternatively, a pressure delivery pipe is attached to Pos. 5 on thepressure collar so that the pressure, enhanced by an additional drag-in on the
pressure collar, is built up from the outlet 6 to the intake 7. This design
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feature ensures that a uniform dent profile along sheet 1 occurs in the semi-
continuous denting process. The dent-profiled sheet is coiled over the roller
9.
When plastic foil is to be dent-profiled, the pressure apparatus is heated
up to the elastic/plastic transition region of the plastic. When even higher
temperatures for an elastic/plastic dent profiling process are required (deep
dents for metal, shallow for glass walls) the pressure collar is replaced by a
temperature-stable sealing package.
The device depicted in Fig. 1 for the manufacture of dent-profiled
rolled sheets can be technically simplified by using rubber covers. The sheet 1
to be dent-profiled and the support helix 4 and the support roller 3 can be
hydraulically tightly encased with flexible, bending covers. Fig. 2 shows the
dent profile in an uncoiled foil section. The distance h of the dent profiles
correspond to the distance h of the support helix 4 in Fig. 1 when a single
support helix is used. The revolving dent fold corresponds to the support line
of the support helix 4. The axial dent fold 10 and the width b are
independently formed during the dent profiling process in Fig. 1. The
20 number of dent structures can be calculated by an empirical evaluation. Fig. 3
shows the uncoiled dent structure resulting from multiple support helices.
The angle alpha in Fig. 3 is larger than the angle alpha in Fig. 2.
Fig. 4 depicts the dent structure in an uncoiled foil produced on a
2 5 device similar to Fig. 1, where equally spaced support rings instead of a
support helix were used. The angle alpha is zero.
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Figs. 5,6,7,8 and 9 depict the cross-sections of the different types of
flexible support elements: Fig. 5 depicts a circular support element 14; Fig. 6
shows an oval support element 15; Fig. 7 depicts a quadrangular support
element 16; Fig. 8 illustrates a trapezoidal support element 17; and Fig. 9
5 shows a triangular support element 18.
Support roller 12 is depicted in the Figs. 5-9. Element 13 depicts the
material to be dent-profiled. Regardless of the type of material used, it is held
by support roller 12. In this depiction support elements 14-18 are rings whose
10 cross-sections are circular, oval, quadrangular, trapezoidal, and triangular, respectively. The support elements can also run in a helical course (as
opposed to being rings), pneumatically or hydraulically fixed, or in the form
of chain links.
When external pressure is applied, which will later be described, dents
appear in the material 13. The shape and sequence of the folds which define
the borders of the dent will be explained later.
Additional spacers guarantee the regular placement of the flexible
20 support elements. The cross-section of the device in Fig. 10 shows the elastic
sleeves 19, for the regular spacing of the support element 14 on the support
roller 12.
The cross-section view in Fig. 11 shows the flat rotating grooves 20,
25 which are also useful for the regular spacing of the support elements 14.
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Fig. 12 shows a dent profile of an uncoiled metallic material sheet
which has been dent-profiled with fixed support rings. Square or quadr-
angular dent structures occur, whereby the straight dent folds 21 line up with
the course of the stiff support rings. The length of the axial dent fold 22
5 corresponds to the distance h of the support rings 14 in Fig. 5.
When flexible support elements are used, hexagonal dent structures
appear which are staggered. Fig. 13 shows an uncoiled material sheet which
has been dent-profiled with a device with flexible support elements and low
10 pressure. The length of the axial dent fold 22 is slightly reduced compared to
the distance h of the support element (prior to dent profiling). The dent fold
21 takes on a zigzag course. Fig. 14 shows that by increasing the denting
pressure the length of the dent fold 22 is further reduced so that
approximately symmetrical, hexagonal shaped dent profiles finally occur.
Fig. 15 shows an uncoiled material sheet which has been dent-profiled
with a device according to Fig. 5 with thin support elements having a small
circular section, whereby the dent troughs 23 in the material sheet press on
the support roller and flatten in the middle. These flattened dent troughs
20 have the advantage that the material sheets can be sandwiched on top of each
other and easily compounded. Furthermore, dent-profiled material with
flattened troughs has a good visual appearance.
Fig. 16 shows a cross-section of a support roller 12 with permanently
2 5 fixed flexible support discs 24. The flexible support discs 24 are axially
deformed on their circumference during the dent profiling of the material
sheet 13 and take a zigzag course in the peripheral direction. Likewise, as
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shown in Fig. 17, the flexible discs 25, which are regularly spaced on the
support roller 12, function as support elements. Depending on the flexibility
(or rigidity), the support discs 24 or the discs 25 are axially deformed to a
greater (or lesser) extent.
Fig. 18 shows an uncoiled surface of a zigzag shaped support element
26, which is permanently fixed to the support roller 12. These support
elements 26 can be made from metallic round or square-shaped profiles,
coiled into a zigzag shape and then affixed to the jacket 12.
Fig. 19 shows an uncoiled surface of a serpentine support element 27,
which is permanently fixed on the support roller 12. Serpentine curves of the
support elements are technically easy to construct. The zigzag or serpentine
support elements 26 and 27 can also be directly milled into the support roller
15 12.
Figs. 20 and 21 show an uncoiled surface zigzag-shaped, flexible support
elements 28, serpentine-shaped support elements 29 which are placed on the
support pins 30 (on the support roller 12). This placement can either be helical20 or ring-shaped with rigid or flexible support elements 28 and 29 placed
around the pins on support roller 12.
Another feature of the invention is that the pressure collar 5 in Fig. 1
has a dent-profiled-like surface which corresponds to the spacing of the
25 support rings 4. The surface of the pressure collar does not necessarily have to
be identical to the complete dent shape. It is sufficient that the surface of the
dent-profiled-like pressure collar is similar to staggered knobs 31 (shown in
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Fig. 22) which are made of ebonite. The shape of the knobs correspond to the
dents. Fig. 22 schematically depicts an aspect of the knobs 31 and the structureof the dent-profiled sheet 32. The dent folds 33 correspond to the lines of the
support rings 4 in Fig. 1.
Fig. 23 schematically depicts the continuous dent-profiling process.
Sheet 32 is continuously advanced over the feeding rollers and over the
support roller 33 on which the support rings 34 are attached. The rotating
profiled band 41 is fed over five guide rollers 42, over the support roller 33,
10 and over band 31. By means of the support rollers 43, the rotating profiled
band 41, which is preferably made of fiber-reinforced material, is pressed on
sheet 32, so that the dent profiling occurs. The deformation pressure is
adjustable by the pressure rollers 43. The dent-profiled band is then coiled up
on the roller 37.
Fig. 24 schematically shows a device with mechanical relaying of the
dent pressure. The device is suitable for continuous manufacture of dent-
profiled material sheets. The sheet material 45 is curved and transported
over the support roller 44 with the support elements 46. A flexible, smooth
20 pressure roller 47 transfers the pressure required for the dent deformation.
The elasticity of the pressure roller 47 and its diameter are chosen so that in
the contact area of the pressure roller 47, where the material sheet receives
the required pressure for the dent process, a segment of approximately 2 dents
in the peripheral direction of the material sheet is indented. The view of the
25 segment serves to explain the contact area. When in operation, the support
rollers 44, the support elements 46 and the pressure roller 47 produce a
continuous line of dents. In the example, the pressure roller 47 is made of
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rubber. As an option, the contact area can comprise less or more than 2 dents
in the peripheral direction.
According to the invention, Fig. 25 depicts an uncoiled, surface of the
5 regularly-spaced axial slits 48 in the flexible pressure roller 47. The slit depth
h2, as depicted in the cross-section, is preferably larger than the impression
depth h2 of the flexible pressure roller 47 during the dent deformation process
as in Fig. 24. Due to the slits 48, the pressure areas formed on the material
sheet by the flexible pressure roller 47 appear like independent pressure areas
10 and cause the required overlapping dent pressure between the flexible
pressure roller 47 and the material sheet 45 to be formed. Without the slits a
straight pressurization ~i.e. not a two-dimensional pressure) would occur
despite the overlapping of the flexible pressure roller 47 and the material
sheet 45. Fig. 26 shows a pressure roller with both axial 48 and radial slits 50.
15 Fig. 27 shows a device with either helical-shaped slits 51 or crossed helical-
shaped slits 52 in the flexible pressure jacket 47. All the mentioned slit
arrangements serve to produce the best possible even two-dimensional dent
pressure.
In a further undepicted example, a flexible pressure roller, made of
rubber or another elastomer, is equipped with a dent-profiled-like or knobbed,
staggered surface which corresponds to the distances on the support elements
46. The knobs are made from either a flexible or rigid material. The knobs
have a shape which is, according to the application example, smaller than the
shape of the dent to be deformed. The knobs create an initial effect when the
dent occurs. Despite the smaller size of the knobs the dents are fully formed
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due to the deformation of the rubber on the pressure roller and the pressure
in the contact area.
In another undepicted example, a stiff pressure roller is fitted with
5 either a dent-profiled-like or knobbed, staggered surface so that thick-walledmaterial sheets can be dent-profiled. The knobs are profiled in such a way that
an indentation occurs but no typical deep-draw deformation characteristics
develop.
The device depicted in Fig. 28 shows a device to manufacture dent-
profiled pipes, even long pipes. The pipe to be deformed 53 is axially
transported and supported on the inside with a helix 54. The helix 54 has a
movement width h and depicts the regularly spaced support elements. Two
rotating pressure rollers 55 and 56 like the pressure roller 47, are placed overthe pipe to be deformed in a peripheral direction and at the position of the
helix 54, and cause the dent-profiling in the pipe. The dent-profiled pipe is
transported in an axial direction by the synchronous movement of the helix
54 and the pressure rollers 55 and 56.
Like the pressure roller 47, the pressure rollers 55 and 56 are made of a
flexible, smooth material, in this case rubber. The elasticity of the pressure
rollers 55 and 56 is selected so that when pressure is put on the pipe, a
pressure element is imprinted which corresponds to approximately two dents
in the peripheral direction of the pipe. The pressure rollers 55 and 56 are
2 5 ideally crowned and placed slightly axial to the angle opposite the pipe to be
dent-profiled. In this way the pressure rollers 55 and 56 generate a pressure
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gradient towards the transport direction of the pipe, so that a continuous
dent-profiling process in the axial direction of the pipe occurs.
In order for both pressure rollers 55 and 56 to produce a flattened dent
5 pressure on the pipe to be deformed (pipe 53), the invention allows for
flexible pressure rollers with slits to be used. Preference is given to helical-shaped slits and also crossed helical-shaped slits which correspond to the
helical dent profiling of the pipe.
In accordance with the invention, both pressure rollers can be used -
also together with additional pressure rollers - to achieve a phased
deformation. For instance, one pressure roller can be equipped with knobs,
thus initiating the dent profiling process and the other without knobs, which
finishes off the deformation. All these processes can be combined with a
15 multiple helix.
In another application example according to Fig. 28, the pipe 53 to be
dent-profiled is turned in an axial direction and transported further. The
synchronously rotating pressure rollers 55 and 56 are permanently installed.
20 The helix 54 is also permanently installed. This process is suitable for the
discontinuous dent profiling of individual pipes. In the example in Fig. 28,
the pressure rollers are driven. They run over the pipe. Instead of this or in
conjunction with the pressure rollers, the pipe can be driven.
2 5 The device depicted in Fig. 29 shows the design of an additional device
used to dent-profile long pipes. The pipe to be deformed 53 is supported on
the inside with a helix 54 and enclosed on the outside with a cylindrical
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pressure collar 57. While the pipe progresses along at a continuous axial
speed, the pressure collar 57 and the helix 54 are simultaneously moved part
of the distance. During this operation the pressure in the pressure collar 57 isbuilt-up, counter-clockwise to the transport direction, by means of a com-
5 pressible medium (e.g. compressed air or a fluid), which flows into thepressure collar 57. The friction losses, caused by the current linkage on the
lamella, result in a pressure gradient. After the pipe walls have been dent-
profiled the pressure collar 57 is relieved of pressure and moved back to its
original position. At the same time the helix 54 is also returned to its original
10 position. This process repeats itself as previously described.
The pressure gradient in the pressure collar 57 is only generated for a
short time at the beginning of the dent-profiling process so that dents develop
in the allowed time. At the end of every denting process the pressure collar 57
15 has a constant denting pressure so that the indentations are identical. In order
to control this process the pressure collar has several pressure ports 59. When
required, the pressure collar 57 can be separated into several sections.
In order to reduce friction losses between the internal pipe wall and the
20 helix 54 during the reversing process, the diameter of the helix 54 is slightly
reduced, preferably by means of a mechanical deformation on the helix 54.
Alternatively, a pneumatical helix can be used. Optionally, the helix and the
mechanical or pneumatical or hydraulic devices can be designed so that the
diameter can be varied. The axial movement is thereby simplified. The helix
2 5 can also be formed by a coiled band.
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Fig. 30 shows the design for manufacturing conical-shaped, dent-
profiled components. The support rings 61 on the conic support roller 60 are
regularly spaced in such a way that the distances between the support rings 61
become larger with the increased diameter of the truncated cone. This is on
5 purpose so that the constant wall thickness of the conic material to be dent-
profiled 62 has a constant number of peripheral dents, despite the variable
diameter of the truncated cone. At the same time the dent pressure in the
area of the larger diameter is lower than in the area of the smaller diameter.
The invention allows for variable dent pressure adjustment in that the conic
10 elastic pressure roller 63, as opposed to the conic support roller 60, is equipped
with a variable angle, inclined and impressed. In accordance with the
invention and for reasons previously described, the elastic pressure roller 63
should preferably be equipped with straight course axial or helical-shaped
slits. Like the other pressure roller 47, the pressure roller 63 can have a dent-
15 profiled-like or a staggered knobbed surface. As the surface profile of the
pressure roller is pre-traced, the distances h on the support rings do not have
to be exactly adhered to as is the case with an elastic, smooth surface without
knobs. According to the invention the choice of the wall thickness of the
conic component 62 is made so that with increased conic diameter the dent
20 profiling can occur with uniform pressure.
Fig. 31 depicts a device to manufacture spherical dent-profiled
components 64. Spheres 65 are packed into the opening 66 so that a tight
sphere packing is achieved. The spheres function as regularly spaced,
2 5 punctual support elements for the dent profiling of the spherical-shaped
component 64. The dent pressure, preferably on thin plastic walls, is achieved
by internal underpressure (vacuum locking 67) and/or by means of external
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excess pressure (submersion in a liquid 68) and then imprinted on the wall to
be profiled. Normally hexagonal and pentagonal dent profiles appear on the
spherical-shaped wall. Once the dent profiling process has finished the
spheres 65 can be removed through the opening 66.
Fig. 32 depicts a device to manufacture calotte shell-shaped, dent-
profiled components 69. The support elements in this process are regularly
spaced support elements, preferably small spheres or hemispheres 71, which
are attached to a spherical support element 70. By means of an elastic toroidal
10 ring 72 and an external straining ring 73 the calotte shells 69 to be dent-
profiled and the spherical support element 70 are tightly bonded to each
other. Dent pressure is applied by internal underpressure and/or external
excess pressure analog to Fig. 31. According to the invention, sh~ll-shaped
and/or rotationally symmetric dent-profiled components, preferably spherical
15 cap bottoms or ellipsoid hollow bodies or shells can be manufactured,
analogous to Figs.31 and 32. These components have a high rigidity and low
specific gravity.
Some of the advantages of the present invention is discussed herein,
20 and in conjunction with Figs. 33-40 where appropriate. According to the
invention cylindrical, conical and shell-shaped dent-profiled components can
also be assembled. In special cases, cylindrical, conical and shell-shaped thin-walled (including the support elements) can be bonded and then
simultaneously dent-profiled by means of internal underpressure and/or
25 external excess pressure. In this way, complicated and multi-dimensional
components with high rigidity and low specific gravity can be manufactured.
Application examples are rigid, lightweight constructions in transport,
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aviation and medicine technology. In sandwich constructions the dent-
structured surface allows for an improved bonding of the secondary
materials.
The devices depicted in Figs. 33-36 schematically show the different
types of shell and dent structures for light reflection purposes (L = light
source): A concave shell with convex dent structures produces a
geometrically directed light reflection with diffused light dispersion. A
concave shell with concave dent structures produces an almost allover
10 diffused light dispersion. A convex shell with concave dent structures
produces an almost allover punctual light dispersion.
Fig. 37 shows a cylindrical multi-chambered container. The dent-
profiled cylindrical wall 74 has a distance h in the revolving dent fold 75 (10
15 in Fig. 4), whereby h corresponds to the distance of the dividing walls to each
other. The dividing walls are affixed to the revolving dent fold 75 on the wall
which, when required, can also be glued together. The calotte shells 76
laterally occlude the multi-chambered containers, thus providing rigid,
weight-saving multi-chambered containers which, in the case of waste
20 disposal bins, also have intake openings and lockable drain openings. These
functions are not shown in Fig. 37.
Fig. 38 shows a heating or cooling plate. Two dent-profiled plates 77 and
78 are pressed together with dent-profiled sides facing each other and then
2 5 glued or soldered. The heating or cooling medium flows through the gaps.
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Fig. 39 shows a design for a double-walled cylindrical container, i.e. for
storing hazardous liquids. The interior wall 79 comprises a dent-profiled
cylinder onto which the externally dent-profiled cylinder 80 is coiled or
wrapped. In order for the dent-profiled walls 79 and 80 to support each other
5 dent structures are used which ideally have a varying twist and varying
angles (Figs. 2,3 and 4). The calotte shells 81 and 82 are glued or welded to the
dent cylinders 79 and 80. The ring annulus 83 serves as a receptacle for testingfluids or heating or cooling mediums. Openings for intake, draining or
monitoring probes are not depicted in Fig. 39.
Fig. 40 shows the principle design of a form with a dent-profiled surface
for the manufacture of vessels according to the extrusion process. A dent-
profiled cylindrical wall 84, with a bottom 85, is placed in a cylindrical
container 86 with a low-boiling fluid medium 87 in the annulus, which
15 contains the condensing coil 88. In order to achieve a better adhesion of thesolidified molten bath (metal) onto the dent-profiled wall, the external
surface has been roughened. The condensing coil 88 serves to cool the form
during the thermic blowing process.
Although the present invention has been described with reference to
specific embodiments, it is appreciated by those skilled in the art that changesin various details may be made without departing from the invention
defined in the appended claims.
2 5 Thus, a method and apparatus for dent profiling has been described.
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