EP2729294A1 - Method and apparatus with relief drum for producing a core for a composite structural panel - Google Patents

Method and apparatus with relief drum for producing a core for a composite structural panel

Info

Publication number
EP2729294A1
EP2729294A1 EP11869427.2A EP11869427A EP2729294A1 EP 2729294 A1 EP2729294 A1 EP 2729294A1 EP 11869427 A EP11869427 A EP 11869427A EP 2729294 A1 EP2729294 A1 EP 2729294A1
Authority
EP
European Patent Office
Prior art keywords
casing
shaping surface
relief drum
sheet material
rolls
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP11869427.2A
Other languages
German (de)
French (fr)
Other versions
EP2729294A4 (en
Inventor
Valentin KHALIULIN
Vladimir BATRAKOV
Yaroslav DANILOV
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Airbus SAS
Original Assignee
Airbus SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Airbus SAS filed Critical Airbus SAS
Publication of EP2729294A1 publication Critical patent/EP2729294A1/en
Publication of EP2729294A4 publication Critical patent/EP2729294A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
    • B29C59/02—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing
    • B29C59/04—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing using rollers or endless belts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
    • B29C53/22—Corrugating
    • B29C53/24—Corrugating of plates or sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/30—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D24/00—Producing articles with hollow walls
    • B29D24/002—Producing articles with hollow walls formed with structures, e.g. cores placed between two plates or sheets, e.g. partially filled
    • B29D24/004—Producing articles with hollow walls formed with structures, e.g. cores placed between two plates or sheets, e.g. partially filled the structure having vertical or oblique ribs

Definitions

  • the invention is pertaining to the field of the methods of production of corrugated constructions with a folded structure used in the capacity of a filler of multilayered panels.
  • the core structure typically is lightweight yet strong, because it has a configuration including hollow spaces as well as interconnected material webs or the like.
  • Typical examples of such core structures include corrugated sheets, honeycomb cellular structures, and the like.
  • Known core structures have a variety of different configurations, and are made of a variety of different materials.
  • folding methods for folding sheet or web materials can be divided into intermittent or discontinuous processes, for example as described in US 5234727, as well as continuous processes.
  • Such continuous processes can be divided into processes with a coupled or mutual lengthwise and crosswise contraction with a simultaneous expansion in the thickness direction of the starting material web (with a single-stage folding operation, for example as disclosed in US 5947885), and processes in which the material web is first subjected to a crosswise contraction and is subsequently subjected to a deformation in a lengthwise direction of the material (in a two-stage folding operation, for example as disclosed in US 4012932).
  • a device for producing a zigzag crimp comprising shaping members reciprocating over a base in guides arranged on both sides of the material being molded.
  • the drive unit of the systems of punches is in the form of a detachable vacuum chamber formed by a bag of gas-tight material capable of sealing said chamber at a side of a blank fed to the working zone between the upper and lower systems of punches.
  • said vacuum chamber follows the contour of the upper and lower punches.
  • US 6913570 Disclosed in US 6913570 are method and apparatus for producing a composite structural panel with a folded material core.
  • a folded core structure is produced by embossing fold lines into a flat planar material web, initiating folds along the fold lines on the upper and lower surfaces of the material web, proceeding with the formation of the folds along the fold lines to deform the material web from its two-dimensional starting configuration to a three-dimensional folded configuration, and post-processing the folded material web to stabilize or fix the folded configuration thereof.
  • a composite structural panel is produced by bonding a cover layer onto at least one surface of the folded core structure.
  • An apparatus preferably includes embossing or creasing rolls to form the fold lines in the material web, air nozzles or folding rolls to initiate the folding process, bristle brush rolls to complete the folding process, and further folding rolls to enhance and fix the folded configuration, optionally in combination with heating, cooling, applying a coating onto or impregnating a resin or binder into the material web.
  • This known invention allows carrying out continuous production of a composite structural panel with a folded material core; however, the apparatus implementing this method has therewith a complicated design and, because of its linear arrangement, has substantial overall dimensions.
  • an apparatus for corrugating a sheet material comprising: one system of punches consisting of identical flat shaping members in the form of parallelograms jointly coupled along their sides and forming a zigzag corrugated surface; a drive unit for the system of punches in the form of a detachable vacuum chamber embracing them and made of an elastic gas-tight material so that it is capable of being sealed at a side of the blank fed to the working zone and replicating the contour of the counter-punches in the process of shaping-evacuation; a member for fixing the system of punches; and a mechanism for tensioning the shaping unit.
  • the system of punches and its drive are made up so as to form a shaping unit.
  • the member for fixing the system of punches is made of a gas-tight cloth and connected to one side of the system of punches along zigzag lines of protrusions.
  • this apparatus carries out the following steps:
  • said sheet material is fed on a relief drum having a shaping surface formed by a casing of a substantially cylindrical shape, said casing provided with a plurality of similar flat rigid plates arranged in the form of parallelograms jointly coupled at their sides; providing adhesion of said sheet material to the shaping surface; and deforming the shaping surface of the relief drum by mutual movement of said flat rigid plates in the casing together with turning simultaneously said relief drum around its axis.
  • the plates are moved in two directions: along the elements of the cylinder determining the shape of the casing and in the circumferential direction perpendicular thereto.
  • the sheet material is pressed against the shaping surface substantially at the half of the circumference of the cylinder base determining the casing shape.
  • the step of removing the molded core further includes calibrating the formed crimps by height.
  • the relief drum used in the method described herein above comprises: a shaping surface and a supporting structure, wherein said shaping surface is formed by a casing of a substantially cylindrical shape, said casing provided with a plurality of similar flat rigid plates arranged in the form of parallelograms jointly coupled at their sides; and said supporting structure comprising:
  • each beam being fixed on a spoke connected to a disk attached to a driving shaft rotatably mounted in an immovable support, wherein one of the spokes is rigidly bound to said disk, whereas the other spokes are arranged on the disk so that they can turn in the plane of the disk; - holders of the casing arranged on the beam so that they can slide along the beams;
  • said mechanisms are configured so that, within one turn of the shaft, an angle between the adjacent spokes and distances between the holders on the corresponding beams change, and when the angle between the spokes is at its maximum, the distance between the holders on the corresponding beams is also at its maximum, but when the angle between the spokes is at its minimum, the distance between the holders on the corresponding beams is also at its minimum.
  • the casing is a sandwich including three joined together layers, wherein the middle layer is formed by plates with clearances between their sides, and the two other layers are fluoroplastic films, so that the portions of the films covering said clearances essentially form a hinged joint of adjacent plates.
  • said layers may be joined together by gluing.
  • the mechanism for mutual angular displacement of the spokes comprises:
  • the mechanism for mutual displacement of the holders comprises: - sliding members arranged on each beam and carrying the holders of the casing;
  • pantograph placed along each beam and comprising a few pairs of hinged intersecting levers, wherein the axles of the hinges coupling said intersecting levers are connected to the sliding members;
  • the subject-matter of the invention is also an apparatus for producing a core of prepreg in the form of sheet material for composite structural panels, said apparatus comprising a forming device and a means for removing the molded core.
  • said forming device comprises described above relief drum and a holding-down device comprising rolls rotatably attached to a rigid frame and encompassing the casing of the relief drum essentially along a half of the circumference of the base of the cylinder determining the casing shape; whereas said means for removing the molded core comprises a frame with rolls rotatably attached to the frame and arranged in two rows opposite one the other, wherein their axes lie in two substantially parallel horizontal planes so that there is a clearance between the rolls of the upper row and the rolls of the lower row, said clearance corresponding to the predetermined crimp height of the molded core.
  • the rolls of the holding-down device are configured so that their position relative to the casing of the relief drum can be adjusted.
  • the means for removing the molded core comprises an additional roll located in the lower row of the rolls on the side facing the relief drum.
  • the rolls of the means for removing the molded core are configured so that their position can be adjusted in a substantially vertical direction.
  • Fig. l shows schematically some successive stages of the method of producing a core for a composite structural panel according to the present invention.
  • Fig.2 shows the apparatus for producing a core for a composite structural panel according to the present invention in a perspective top view.
  • Fig.3 is an exploded perspective view of the apparatus shown in Fig.2.
  • Fig.4 is a perspective view of the relief drum shown in Fig.3, but without the casing.
  • Fig.5 is an exploded perspective view of the relief drum shown in Fig.4.
  • Fig.6 is a perspective view of the mechanism for a mutual angular displacement of the spokes, but without the central ring.
  • Fig.7 is a perspective view of the beam and the mechanism for mutual displacement of the holders, but without the side rings.
  • Fig.8 is a perspective view of the casing of the relief drum according to the present invention.
  • Fig.9 is a perspective view of a part of the casing shown in Fig.8.
  • Fig.l explains schematically the principle of shaping up a corrugated surface of sheet material in accordance with the present invention.
  • prepreg in the form of sheet material 1 is fed to a smooth area of the shaping surface of a relief drum 2, and this sheet material is pressed against said area so as to provide adhesion of said sheet material 1 to the shaping surface.
  • the shaping surface of the relief drum 2 is formed by a casing 3 of a substantially cylindrical shape, said casing provided with a plurality of similar flat rigid plates 4 arranged in the form of parallelograms jointly coupled at their sides (Fig.8).
  • the design of the relief drum 2 will be described below.
  • deforming the shaping surface of the relief drum 2 is carried out by mutual movement of said flat rigid plates 4 in the casing 3 with a simultaneous turn of said relief drum 2 around its axis.
  • the plates 4 are moved in two directions: along the elements of the cylinder determining the shape of the casing 3, and in the circumferential direction perpendicular to the direction along the cylinder elements.
  • said sheet material 1 pressed against the relief drum 2 by means of a holding- down device 5 with rolls 6 takes the form of a corrugated surface.
  • the apparatus allowing to carry out the stages described herein above consists of basically from the following three components: the relief drum 2, the holding-down device 5 and a means 7 for removing the molded core.
  • the relief drum 2 shown in Fig.3 comprises a shaping surface of a substantially cylindrical shape and a supporting structure.
  • the shaping surface is formed by the casing 3 of a substantially cylindrical shape (Fig.8), said casing provided with a plurality of similar flat rigid plates 4 arranged in the form of parallelograms jointly coupled at their sides (Fig.9).
  • the casing 3 is a structure including three joined together layers. Said layers preferably are joined together by gluing. Moreover said layers may be joined together by another acceptable method of joining. For example said layers may be joined together by heat sealing. Said structure rolled up so as to form a tube, wherein the middle layer is formed by the plates 4 with gaps between their sides, and the two outer layers 8 and 9 are fluoroplastic films, so that the portions of the films covering said gaps essentially form a hinged joint between the adjacent plates 4.
  • the supporting structure comprises a few beams 10 (Figs.4, 5 and 7) arranged along the elements of the cylinder determining the shape of the casing 3 and distributed around the circumference of the cylinder base. As shown in Fig.7, sliding members 11 carrying holders 12 of the casing 3 are attached to each beam 10 so as to be slideable along it. Each beam 10 is fixed to a spoke 13 connected to a disk 14 attached to a driving shaft 15. In order to improve reliability of fixing the beams 10 to the spokes 13, the latter can be provided with a strut 16 (Fig.6).
  • the shaft 15 is rotatably mounted in an immovable support 17 and connected to a drive for its rotation (not shown).
  • spokes are rigidly bound to the disk 14, whereas the other spokes 13 are arranged on the disk so that they can turn in the plane of this disk; hence, the spokes are capable of mutual angular displacement in the plane of the disk 14.
  • the casing 3 is attached to the holders 12 so that the holders are arranged within the zone of clearances between the plates 4.
  • the supporting structure comprises also a mechanism for mutual angular displacement of the spokes 13 and a mechanism for mutual displacement of the holders 12.
  • the mechanism for mutual angular displacement of the spokes 13 comprises a few hinged pairs of levers 18, the free ends of which in each pair are hinged to two adjacent spokes 13.
  • a roller 19 is attached to the axle of each hinge connecting a pair of the levers 18, whereas a central ring 20 having an outer edge and an inner edge is fixed to an immovable support 17 so that the inner edge 21 is in contact with the rollers 19.
  • the profile of the inner edge 21 of the central ring 20 is egg-shaped so that, during rotation of the disk 14, the rollers 19 rotating over the inner edge 21 of the central ring 20 displace radially the axles of the hinges connecting a pair of levers 18 to one the other so as to turn thereby the adjacent spokes either drawing them nearer to one the other or moving them farther apart from one the other.
  • the central ring 20 is a thin-sheet structure that, for saving the material when making it, can be made to consist of a few, for instance, three parts.
  • each part of the central ring 20 is made in a machine tool with a software control in conformity with a mathematic model.
  • the fitting holes (not shown) in the central ring 20 are made so that they are not of circular shape.
  • the mechanism for mutual displacement of the holders 12 comprises the above- mentioned sliding members 1 1 attached to each beam so that they can slide along them, and carrying the holders 12 of the casing 3. Rollers 22 are attached to each of the outermost sliding members 1 1 of each beam 10.
  • the sliding members 1 1 are interconnected with each other by means of a pantograph 23 placed along each beam and comprising a few pairs of intersecting levers 24 hinged with each other. In this case, the axles of the hinges coupling the intersecting levers 24 are connected to the sliding members 1 1.
  • Two side rings 25 are fixed to the immovable support 17 on both sides from the central ring 20.
  • the surface of each of the side rings 25 facing the central ring 20 is in contact with the roller 22 arranged on the corresponding outer sliding member 1 1 , said surface being inclined relative to the plane, in which essentially lies the central ring 20.
  • the design of each of the side rings 25 is similar to the design of the central ring 20 and can also consist of a few parts that are butt-joined when mounting the parts onto the immovable support 17.
  • the means for fastening these rings to the immovable support 17 are made so that they are adjustable (not shown), for instance, with the use of threaded connections.
  • the side rings are placed symmetrically relative to an essentially vertical plane in which lies the central ring 20.
  • Said mechanisms for mutual angular displacement of the spokes and for mutual displacement of the holders are configured so that, within one turn of the shaft 15, the angle between the adjacent spokes 13 and the distances between the holders 12 on the corresponding beams 10 change and, when the angle between the spokes 13 is at its maximum, the distance between the holders 12 on the corresponding beams 10 is also at its maximum, though when the angle between the spokes 13 is at its minimum, the distance between the holders 12 on the corresponding beams 10 is also at its minimum.
  • the surface of the casing 3 is practically smooth.
  • Coordination of said mechanisms is ensured by selecting both the profile and the angular position of the central ring 20 and by the magnitude of the inclination angle of the side rings 25.
  • the holding-down device 5 comprises a rigid frame 26, to which the rolls 6 are attached so that they can rotate about their own axis.
  • the rolls 6 are attached to the frame 26 in a few, for instance, three groups by means of brackets 27.
  • brackets 27 For instance, five rolls 6 are mounted on each bracket.
  • the brackets 27 with the rolls 6 are placed on the frame 26 in such a manner that, when the frame 26 is positioned appropriately relative to the immovable support 17 of the relief drum 2, the rolls 6 enclose the casing 3 of the relief drum 2 essentially around one half the circumference.
  • the rolls 6 are placed on the brackets 27 so that their position can be adjusted relative to the casing 3 of the relief drum 2.
  • the axles of the rolls 6 are connected to the brackets 27, for instance, by means of threaded rods inserted into the openings of the brackets 27 and fixed relative to these brackets by nuts.
  • the surface of the rolls 6 can be coated with an antiadhesion material preventing sticking of the prepreg to the rolls.
  • the rolls 6 can contain an outer layer of resilient material.
  • the means 7 for removing the molded core comprises a frame 28 with rolls 29, which are attached to the frame so that they can rotate about their own axes, while being arranged in two rows opposite to each other.
  • the axles of the rolls 29 lie in two substantially parallel horizontal planes so that there is a clearance between the rolls of the upper row and the rolls of the lower row, the clearance corresponding to the predetermined height of the crimps in the molded core.
  • the rolls 29 are made so that their position can be adjusted in an essentially vertical direction. This allows, after the molded core passes through the means 7, to calibrate the height of the crimps produced in the course of molding.
  • the means for such adjustment can be implemented similarly to the means for adjusting the position of the axles of the rolls 6 relative to the brackets 27 in the holding-down device 5, as described herein above.
  • the means 7 for removing the molded core can comprise a supplementary roll 29a arranged within the lower row of the rolls 29 on that side thereof, which faces the relief drum 2.
  • This supplementary roll 29a allows providing a support for the molded core leaving the relief drum 2 and deflecting it into the clearance between the rows of the rolls 29.
  • the mechanisms of the supporting structure of the relief drum are to be set up so that the upper part of the surface of the casing 3 has essentially a smooth shape, i.e., it has neither projections nor hollows, whereas the zigzag crimps of maximum height are formed within the lower part of the surface of the casing 3.
  • the crimps When passing from the upper part of the casing 3 to its lower part, at first the crimps will appear, the height of which increases up to its maximum towards the lower part of the casing 3.
  • Such a shape of the surface of the casing 3 is ensured by appropriate adjustment of the mechanisms for mutual angular displacement of the spokes 13 and for mutual displacement of the holders 12 as a result of choosing both the corresponding shape for the inner edge 21 of the central ring 20 and the angular orientation of this ring, as well as due to inclining the side rings 25.
  • the holding-down device 5 is to be placed relative to the relief drum 2 so that the rolls 6 would actually enclose uniformly the casing of the relief drum essentially over half the circumference that forms up the base of the cylinder defining the shape of the casing, i.e., would enclose the entire surface of the casing 3 located between its upper and lower parts as shown in Fig.2.
  • the means 7 for removing the molded core is placed relative to the relief drum 2 so that the supplementary roll 29a would be arranged close to the lower part of the casing 3.
  • the axles of the rolls 29 are parallel with the axis of rotation of the relief drum and, correspondingly, with the axles of the rolls 6 of the holding-down device 5 (Fig.2).
  • the profile of the inner edge 21 of the central ring 20 is designed so that, at any angular position of the disk 14, the angle between the adjacent spokes is at its maximum within the upper part of the relief drum 2, whereas this angle is at its minimum within the lower part of the relief drum 2.
  • the distance between the adjacent beams 10 attached to the spokes 13 and carrying the holders 12 of the casing 3 changes gradually, in the process of turning the disk 14 through one revolution, from its maximum within the upper part of the relief drum 2 to its minimum within the lower part of the relief drum 2 and then again to its maximum as this one revolution of the disk 14 is being completed.
  • the plates 4 get gradually displaced inside the casing 3 arranged on the holders 12 in the tangential direction from the position, when they define an essentially smooth surface (within the upper part of the casing 3), to the position, when they define a corrugated surface with the maximum height of the crimps (within the lower part of the casing 3), and back again to the position, when they define an essentially smooth surface.
  • the mutual displacement of the plates 4 takes place in the direction that is parallel with the axis of the shaft 15; in this case, the dependency of such displacement from the angle of rotation of the disk 14 is similar to the dependency of the mutual displacement of the plates in the tangential direction, which has been described herein above.
  • the displacement of the plates in the axial direction takes place in the following way.
  • each of the rollers 22 mounted on each one of the outermost sliding members 1 1 of every beam 10 is in contact with the surface of the corresponding side ring 25. Since the rings 25 are arrange on the immovable support having an inclination relative to the vertical plane, in which essentially lies the central ring, the rollers 22 of every beam 10 are periodically moving nearer to one another and then back away from one another during rotation of the disk 14. In doing so, the distance between the adjacent sliding members 1 1 of every beam 10, which carry the holders 12 of the casing 3, gets also changed, because these sliding members are interconnected with each other by means of the pantograph 23.
  • the inclination of the side rings 25 is selected so that the maximum distance between the adjacent sliding members 1 1 would correspond to the maximum distance between the beams 10, whereas the minimum distance between the adjacent sliding members 1 1 - to the minimum distance between the beams 10.
  • Prepreg is fed onto the upper part of the rotating relief drum 2 in the form of sheet material, which is pressed against the surface of the casing 3 by means of the roll 6 of the holding-down device 5.
  • the value of adhesion is selected so that the sheet material 1 , when pressed against the casing 3 by the rolls 6, would not tear off from it, while the surface of the casing 3 is changed, thus repeating the shape thereof, but as soon as the relief drum is turned around through 180°, the corrugated sheet material 1 would detach from the surface of the casing 3 under the influence of its own weight.
  • the corrugated sheet material 1 moves in the direction away from the relief drum, while being at first supported by the supplementary roll 29a of the means 7 for removing the molded core and subsequently entering into the clearance between the rolls 29 of the upper and lower rows of the means 7 for removing the molded core.
  • the above- mentioned clearance is to be set at a predetermined value, so that when the molded core passes between the rolls 29, the height of its crimps gets calibrated.
  • the sheet material can be fed to the relief drum both in the form of a continuous band or as separate predetermined cut-off lengths.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Shaping Of Tube Ends By Bending Or Straightening (AREA)
  • Moulding By Coating Moulds (AREA)

Abstract

The invention is pertaining to the field of the methods of production of corrugated constructions with a folded structure used in the capacity of a filler of multilayered panels. A method for producing a core for a composite structural panel, said method comprising the following steps: feeding prepreg in the form of sheet material (1) to a smooth shaping surface formed by a casing (3) of a substantially cylindrical shape, said casing provided with a plurality of similar flat rigid plates arranged in the form of parallelograms jointly coupled at their sides; providing adhesion of said sheet material (1) to the shaping surface; pressing said sheet material against said shaping surface; deforming the shaping surface by mutual movement of said flat rigid plates in the casing (3) together with turning simultaneously said relief drum (2) around its axis; and removing the molded core. The subject-matters of the invention include also an apparatus for producing a core for a composite structural panel as well as a relief drum included into this apparatus and comprising said shaping surface.

Description

METHOD AND APPARATUS WITH RELIEF DRUM FOR PRODUCING A CORE FOR A COMPOSITE STRUCTURAL PANEL
Technical Field
The invention is pertaining to the field of the methods of production of corrugated constructions with a folded structure used in the capacity of a filler of multilayered panels.
Background Art
It is generally known to form lightweight structural panels including a lightweight core structure sandwiched between two cover layers. The core structure typically is lightweight yet strong, because it has a configuration including hollow spaces as well as interconnected material webs or the like. Typical examples of such core structures include corrugated sheets, honeycomb cellular structures, and the like. Known core structures have a variety of different configurations, and are made of a variety of different materials.
Separately, it is known to form folded structures for various applications through the use of various different methods. These folding methods for folding sheet or web materials can be divided into intermittent or discontinuous processes, for example as described in US 5234727, as well as continuous processes. Such continuous processes, in turn, can be divided into processes with a coupled or mutual lengthwise and crosswise contraction with a simultaneous expansion in the thickness direction of the starting material web (with a single-stage folding operation, for example as disclosed in US 5947885), and processes in which the material web is first subjected to a crosswise contraction and is subsequently subjected to a deformation in a lengthwise direction of the material (in a two-stage folding operation, for example as disclosed in US 4012932).
Known is a device for producing a zigzag crimp according to US 3992162, comprising shaping members reciprocating over a base in guides arranged on both sides of the material being molded.
The shortcomings of this device consist in complexity of its design, high labour content of producing the shaping members and also impossibility of producing a zigzag corrugation with a large amplitude of zigzag lines. Known is an apparatus for corrugating sheet materials according to RU 21 18217, comprising systems of upper and lower punches. Each system consists of identical flat shaping members in the form of parallelograms jointly connected to one another along their sides and forming a corrugated surface. Mutual orientation of the upper and lower systems of punches is provided by means of upper and lower stoppers in the form of multiple-link units having flat members jointly connected to one another for forming corrugation. Said upper and lower stoppers are connected by means of cylindrical hinges with the systems of upper and lower punches, respectively. Elastic members are secured to the surface of said multiple-link units. The drive unit of the systems of punches is in the form of a detachable vacuum chamber formed by a bag of gas-tight material capable of sealing said chamber at a side of a blank fed to the working zone between the upper and lower systems of punches. In the process of shaping-evacuation, said vacuum chamber follows the contour of the upper and lower punches.
The shortcomings of this apparatus are as follows: impossibility to ensure precise positioning of the upper system of punches with respect to the lower system of punches throughout the entire surface of a blank by means of locators, this leading to a poorer quality of the zigzag crimp thus produced; complicated implementation of extending the upper and lower systems of punches prior to fitting the blank; insufficient power of the vacuum drive for imparting a dense relief to the part if the blank has a high rigidity; as well as complexity of the design.
Disclosed in US 6913570 are method and apparatus for producing a composite structural panel with a folded material core.
A folded core structure is produced by embossing fold lines into a flat planar material web, initiating folds along the fold lines on the upper and lower surfaces of the material web, proceeding with the formation of the folds along the fold lines to deform the material web from its two-dimensional starting configuration to a three-dimensional folded configuration, and post-processing the folded material web to stabilize or fix the folded configuration thereof. A composite structural panel is produced by bonding a cover layer onto at least one surface of the folded core structure. An apparatus preferably includes embossing or creasing rolls to form the fold lines in the material web, air nozzles or folding rolls to initiate the folding process, bristle brush rolls to complete the folding process, and further folding rolls to enhance and fix the folded configuration, optionally in combination with heating, cooling, applying a coating onto or impregnating a resin or binder into the material web. This known invention allows carrying out continuous production of a composite structural panel with a folded material core; however, the apparatus implementing this method has therewith a complicated design and, because of its linear arrangement, has substantial overall dimensions. Along with this, the process of forming the corrugated surface is carried out through the utilization of several shaping means arranged in series, but this requires to ensure their strict coordination with each other and, under real conditions, will inevitably lead to forming irregularities in the shape of the corrugated surface.
Known is an apparatus for corrugating a sheet material according to RU 2317168, comprising: one system of punches consisting of identical flat shaping members in the form of parallelograms jointly coupled along their sides and forming a zigzag corrugated surface; a drive unit for the system of punches in the form of a detachable vacuum chamber embracing them and made of an elastic gas-tight material so that it is capable of being sealed at a side of the blank fed to the working zone and replicating the contour of the counter-punches in the process of shaping-evacuation; a member for fixing the system of punches; and a mechanism for tensioning the shaping unit. The system of punches and its drive are made up so as to form a shaping unit. The member for fixing the system of punches is made of a gas-tight cloth and connected to one side of the system of punches along zigzag lines of protrusions.
During its work, this apparatus carries out the following steps:
- feeding prepreg in the form of sheet material to a smooth shaping surface;
- pressing said sheet material against said shaping surface;
- deforming the shaping surface to form a corrugated surface, so that said sheet material pressed against the shaping surface takes the form of the corrugated surface; and - removing the molded core.
This known apparatus has smaller overall dimensions as compared against the apparatus according to US 6913570; however, its shortcomings are as follows: discontinuity of the process of producing a folded structure; absence of calibrating the height of the folds thus shaped up; and also the necessity of using both mechanical and pneumatic systems in the drive of the punches.
It is an object of the present invention to eliminate the above-mentioned shortcomings of the known technical solutions and, in particular, to improve efficiency and quality in production of a folded structure, to simplify the design and to widen the scope of working of the equipment while ensuring simultaneously its compactness. Summary of Invention
The above-mentioned object is accomplished in the proposed method of producing a core for a composite structural panel, said method comprising the following steps:
- feeding prepreg in the form of sheet material to a smooth shaping surface;
- pressing said sheet material against said shaping surface;
- deforming the shaping surface to form zigzag crimps, so that said sheet material pressed against the shaping surface takes the form of a deformed shaping surface; and
- removing the molded core.
According to the invention, said sheet material is fed on a relief drum having a shaping surface formed by a casing of a substantially cylindrical shape, said casing provided with a plurality of similar flat rigid plates arranged in the form of parallelograms jointly coupled at their sides; providing adhesion of said sheet material to the shaping surface; and deforming the shaping surface of the relief drum by mutual movement of said flat rigid plates in the casing together with turning simultaneously said relief drum around its axis.
Preferably, the plates are moved in two directions: along the elements of the cylinder determining the shape of the casing and in the circumferential direction perpendicular thereto.
Preferably, the sheet material is pressed against the shaping surface substantially at the half of the circumference of the cylinder base determining the casing shape.
Preferably, the step of removing the molded core further includes calibrating the formed crimps by height.
The above-mentioned object is accomplished also owing to that the relief drum used in the method described herein above comprises: a shaping surface and a supporting structure, wherein said shaping surface is formed by a casing of a substantially cylindrical shape, said casing provided with a plurality of similar flat rigid plates arranged in the form of parallelograms jointly coupled at their sides; and said supporting structure comprising:
- a few beams arranged along the elements of the cylinder determining the shape of the casing and distributed along the circumference of the cylinder base, each beam being fixed on a spoke connected to a disk attached to a driving shaft rotatably mounted in an immovable support, wherein one of the spokes is rigidly bound to said disk, whereas the other spokes are arranged on the disk so that they can turn in the plane of the disk; - holders of the casing arranged on the beam so that they can slide along the beams;
- a mechanism for a mutual angular displacement of the spokes; and
- a mechanism for a mutual displacement of the holders;
wherein said mechanisms are configured so that, within one turn of the shaft, an angle between the adjacent spokes and distances between the holders on the corresponding beams change, and when the angle between the spokes is at its maximum, the distance between the holders on the corresponding beams is also at its maximum, but when the angle between the spokes is at its minimum, the distance between the holders on the corresponding beams is also at its minimum.
Preferably, the casing is a sandwich including three joined together layers, wherein the middle layer is formed by plates with clearances between their sides, and the two other layers are fluoroplastic films, so that the portions of the films covering said clearances essentially form a hinged joint of adjacent plates.
Preferably said layers may be joined together by gluing.
Preferably, the mechanism for mutual angular displacement of the spokes comprises:
- a few hinged pairs of levers with free ends in each pair being hinged to the two adjacent spokes;
- a roller attached to the axle of each hinge connecting a pair of the levers; and
- a central ring having an outer edge and an inner edge and fixed on the immovable support so that the inner edge is in contact with said rollers, whereas its profile is egg-shaped.
Preferably, the mechanism for mutual displacement of the holders comprises: - sliding members arranged on each beam and carrying the holders of the casing;
- rollers attached to each of the outer sliding members of each beam;
- a pantograph placed along each beam and comprising a few pairs of hinged intersecting levers, wherein the axles of the hinges coupling said intersecting levers are connected to the sliding members; and
- two side rings fixed to the immovable support on both sides from the central ring so that the surface of each of the side rings facing the central ring is in contact with the roller arranged on the corresponding outer sliding member, whereas said surface is inclined relative to the plane, in which essentially lies the central ring. Besides, the subject-matter of the invention is also an apparatus for producing a core of prepreg in the form of sheet material for composite structural panels, said apparatus comprising a forming device and a means for removing the molded core.
According to the invention, said forming device comprises described above relief drum and a holding-down device comprising rolls rotatably attached to a rigid frame and encompassing the casing of the relief drum essentially along a half of the circumference of the base of the cylinder determining the casing shape; whereas said means for removing the molded core comprises a frame with rolls rotatably attached to the frame and arranged in two rows opposite one the other, wherein their axes lie in two substantially parallel horizontal planes so that there is a clearance between the rolls of the upper row and the rolls of the lower row, said clearance corresponding to the predetermined crimp height of the molded core.
Preferably, the rolls of the holding-down device are configured so that their position relative to the casing of the relief drum can be adjusted.
Preferably, the means for removing the molded core comprises an additional roll located in the lower row of the rolls on the side facing the relief drum.
Preferably, the rolls of the means for removing the molded core are configured so that their position can be adjusted in a substantially vertical direction.
Brief Description of the Drawings
Further features, advantages and objects of the present invention would become obvious to a person skilled in the art, when reading the following detailed description of the embodiments of the present invention, if viewed in conjunction with the figures of the enclosed drawings.
Fig. l shows schematically some successive stages of the method of producing a core for a composite structural panel according to the present invention.
Fig.2 shows the apparatus for producing a core for a composite structural panel according to the present invention in a perspective top view.
Fig.3 is an exploded perspective view of the apparatus shown in Fig.2.
Fig.4 is a perspective view of the relief drum shown in Fig.3, but without the casing.
Fig.5 is an exploded perspective view of the relief drum shown in Fig.4.
Fig.6 is a perspective view of the mechanism for a mutual angular displacement of the spokes, but without the central ring. Fig.7 is a perspective view of the beam and the mechanism for mutual displacement of the holders, but without the side rings.
Fig.8 is a perspective view of the casing of the relief drum according to the present invention.
Fig.9 is a perspective view of a part of the casing shown in Fig.8.
Preferred Embodiment
Fig.l explains schematically the principle of shaping up a corrugated surface of sheet material in accordance with the present invention. At the stage shown in Fig. la, prepreg in the form of sheet material 1 is fed to a smooth area of the shaping surface of a relief drum 2, and this sheet material is pressed against said area so as to provide adhesion of said sheet material 1 to the shaping surface. The shaping surface of the relief drum 2 is formed by a casing 3 of a substantially cylindrical shape, said casing provided with a plurality of similar flat rigid plates 4 arranged in the form of parallelograms jointly coupled at their sides (Fig.8). The design of the relief drum 2 will be described below.
Next, as shown in Fig. lb, deforming the shaping surface of the relief drum 2 is carried out by mutual movement of said flat rigid plates 4 in the casing 3 with a simultaneous turn of said relief drum 2 around its axis. The plates 4 are moved in two directions: along the elements of the cylinder determining the shape of the casing 3, and in the circumferential direction perpendicular to the direction along the cylinder elements. In doing so, said sheet material 1 pressed against the relief drum 2 by means of a holding- down device 5 with rolls 6 takes the form of a corrugated surface. The mechanism ensuring deformation of the shaping surface when turning the drum 2 as well as the design of the holding-down device will be described in detail further on.
After this, as shown in Fig. lc, the molded core is removed.
As shown in Figs.2 and 3, the apparatus allowing to carry out the stages described herein above consists of basically from the following three components: the relief drum 2, the holding-down device 5 and a means 7 for removing the molded core.
Further on, the design of the relief drum 2 that is the main component of said apparatus will be described in detail with references to Figs.3 to 9.
The relief drum 2 shown in Fig.3 comprises a shaping surface of a substantially cylindrical shape and a supporting structure.
The shaping surface is formed by the casing 3 of a substantially cylindrical shape (Fig.8), said casing provided with a plurality of similar flat rigid plates 4 arranged in the form of parallelograms jointly coupled at their sides (Fig.9). Essentially, the casing 3 is a structure including three joined together layers. Said layers preferably are joined together by gluing. Moreover said layers may be joined together by another acceptable method of joining. For example said layers may be joined together by heat sealing. Said structure rolled up so as to form a tube, wherein the middle layer is formed by the plates 4 with gaps between their sides, and the two outer layers 8 and 9 are fluoroplastic films, so that the portions of the films covering said gaps essentially form a hinged joint between the adjacent plates 4.
The supporting structure comprises a few beams 10 (Figs.4, 5 and 7) arranged along the elements of the cylinder determining the shape of the casing 3 and distributed around the circumference of the cylinder base. As shown in Fig.7, sliding members 11 carrying holders 12 of the casing 3 are attached to each beam 10 so as to be slideable along it. Each beam 10 is fixed to a spoke 13 connected to a disk 14 attached to a driving shaft 15. In order to improve reliability of fixing the beams 10 to the spokes 13, the latter can be provided with a strut 16 (Fig.6). The shaft 15 is rotatably mounted in an immovable support 17 and connected to a drive for its rotation (not shown). One of the spokes, and namely, the one designated 13a in Fig.6, is rigidly bound to the disk 14, whereas the other spokes 13 are arranged on the disk so that they can turn in the plane of this disk; hence, the spokes are capable of mutual angular displacement in the plane of the disk 14.
The casing 3 is attached to the holders 12 so that the holders are arranged within the zone of clearances between the plates 4.
The supporting structure comprises also a mechanism for mutual angular displacement of the spokes 13 and a mechanism for mutual displacement of the holders 12.
The mechanism for mutual angular displacement of the spokes 13 comprises a few hinged pairs of levers 18, the free ends of which in each pair are hinged to two adjacent spokes 13. A roller 19 is attached to the axle of each hinge connecting a pair of the levers 18, whereas a central ring 20 having an outer edge and an inner edge is fixed to an immovable support 17 so that the inner edge 21 is in contact with the rollers 19. The profile of the inner edge 21 of the central ring 20 is egg-shaped so that, during rotation of the disk 14, the rollers 19 rotating over the inner edge 21 of the central ring 20 displace radially the axles of the hinges connecting a pair of levers 18 to one the other so as to turn thereby the adjacent spokes either drawing them nearer to one the other or moving them farther apart from one the other.
The central ring 20 is a thin-sheet structure that, for saving the material when making it, can be made to consist of a few, for instance, three parts. In this case, each part of the central ring 20 is made in a machine tool with a software control in conformity with a mathematic model. In order to ensure the possibility for mounting precisely the central ring 20 on the immovable support 17, the fitting holes (not shown) in the central ring 20 are made so that they are not of circular shape.
The mechanism for mutual displacement of the holders 12 comprises the above- mentioned sliding members 1 1 attached to each beam so that they can slide along them, and carrying the holders 12 of the casing 3. Rollers 22 are attached to each of the outermost sliding members 1 1 of each beam 10. The sliding members 1 1 are interconnected with each other by means of a pantograph 23 placed along each beam and comprising a few pairs of intersecting levers 24 hinged with each other. In this case, the axles of the hinges coupling the intersecting levers 24 are connected to the sliding members 1 1.
Two side rings 25 are fixed to the immovable support 17 on both sides from the central ring 20. In this case, the surface of each of the side rings 25 facing the central ring 20 is in contact with the roller 22 arranged on the corresponding outer sliding member 1 1 , said surface being inclined relative to the plane, in which essentially lies the central ring 20. The design of each of the side rings 25 is similar to the design of the central ring 20 and can also consist of a few parts that are butt-joined when mounting the parts onto the immovable support 17. In order to ensure precise mounting of the side rings 25 on the immovable support 17, the means for fastening these rings to the immovable support 17 are made so that they are adjustable (not shown), for instance, with the use of threaded connections. Preferably, the side rings are placed symmetrically relative to an essentially vertical plane in which lies the central ring 20.
Said mechanisms for mutual angular displacement of the spokes and for mutual displacement of the holders are configured so that, within one turn of the shaft 15, the angle between the adjacent spokes 13 and the distances between the holders 12 on the corresponding beams 10 change and, when the angle between the spokes 13 is at its maximum, the distance between the holders 12 on the corresponding beams 10 is also at its maximum, though when the angle between the spokes 13 is at its minimum, the distance between the holders 12 on the corresponding beams 10 is also at its minimum. In this case, when the angle between the spokes 13 is at its maximum, and the distance between the holders 12 on the corresponding beams 10 is also at its maximum, the surface of the casing 3 is practically smooth.
Coordination of said mechanisms is ensured by selecting both the profile and the angular position of the central ring 20 and by the magnitude of the inclination angle of the side rings 25.
Further on, the holding-down device 5 and the means 7 for removing the molded core will be described with reference to Fig.3.
The holding-down device 5 comprises a rigid frame 26, to which the rolls 6 are attached so that they can rotate about their own axis. Preferably, the rolls 6 are attached to the frame 26 in a few, for instance, three groups by means of brackets 27. For instance, five rolls 6 are mounted on each bracket. The brackets 27 with the rolls 6 are placed on the frame 26 in such a manner that, when the frame 26 is positioned appropriately relative to the immovable support 17 of the relief drum 2, the rolls 6 enclose the casing 3 of the relief drum 2 essentially around one half the circumference. In order to ensure the possibility for uniform pressing of a deformable sheet material against the surface of the casing 3 of the relief drum 2, the rolls 6 are placed on the brackets 27 so that their position can be adjusted relative to the casing 3 of the relief drum 2. For this purpose, the axles of the rolls 6 are connected to the brackets 27, for instance, by means of threaded rods inserted into the openings of the brackets 27 and fixed relative to these brackets by nuts. The surface of the rolls 6 can be coated with an antiadhesion material preventing sticking of the prepreg to the rolls. Besides, the rolls 6 can contain an outer layer of resilient material.
The means 7 for removing the molded core comprises a frame 28 with rolls 29, which are attached to the frame so that they can rotate about their own axes, while being arranged in two rows opposite to each other. The axles of the rolls 29 lie in two substantially parallel horizontal planes so that there is a clearance between the rolls of the upper row and the rolls of the lower row, the clearance corresponding to the predetermined height of the crimps in the molded core. The rolls 29 are made so that their position can be adjusted in an essentially vertical direction. This allows, after the molded core passes through the means 7, to calibrate the height of the crimps produced in the course of molding. The means for such adjustment can be implemented similarly to the means for adjusting the position of the axles of the rolls 6 relative to the brackets 27 in the holding-down device 5, as described herein above. In addition to this, the means 7 for removing the molded core can comprise a supplementary roll 29a arranged within the lower row of the rolls 29 on that side thereof, which faces the relief drum 2. This supplementary roll 29a allows providing a support for the molded core leaving the relief drum 2 and deflecting it into the clearance between the rows of the rolls 29. In order to simplify adjustment of the mutual position of the relief drum and the means 7 for removing the molded core, there are legs 30 on the frame 28, the height of these legs being adjustable.
The process of producing the core for composite structural panels by means of the apparatus described herein above is accomplished as follows.
The terms "upper" and "lower" as used in the further description are determined with respect to the apparatus shown in Fig.2. In other words, the parts of the apparatus elements located at a minimum distance from the essentially horizontal surface, whereon placed are the immovable support 17 of the relief drum 2, the rigid frame 26 of the holding-down device 5 and the frame 28 of the means 7 for removing the molded core, are named as lower ones, while the parts of the apparatus elements located at a maximum distance from said surface are named as upper ones.
Prior to starting said process, the mechanisms of the supporting structure of the relief drum are to be set up so that the upper part of the surface of the casing 3 has essentially a smooth shape, i.e., it has neither projections nor hollows, whereas the zigzag crimps of maximum height are formed within the lower part of the surface of the casing 3. When passing from the upper part of the casing 3 to its lower part, at first the crimps will appear, the height of which increases up to its maximum towards the lower part of the casing 3.
Such a shape of the surface of the casing 3 is ensured by appropriate adjustment of the mechanisms for mutual angular displacement of the spokes 13 and for mutual displacement of the holders 12 as a result of choosing both the corresponding shape for the inner edge 21 of the central ring 20 and the angular orientation of this ring, as well as due to inclining the side rings 25.
The holding-down device 5 is to be placed relative to the relief drum 2 so that the rolls 6 would actually enclose uniformly the casing of the relief drum essentially over half the circumference that forms up the base of the cylinder defining the shape of the casing, i.e., would enclose the entire surface of the casing 3 located between its upper and lower parts as shown in Fig.2. The means 7 for removing the molded core is placed relative to the relief drum 2 so that the supplementary roll 29a would be arranged close to the lower part of the casing 3. In this case, the axles of the rolls 29 are parallel with the axis of rotation of the relief drum and, correspondingly, with the axles of the rolls 6 of the holding-down device 5 (Fig.2).
When the shaft 15 is rotated by the drive (not shown), the disk 14 begins to rotate as well. In this case, the spoke 13a also rotates together with the disk 14, since it is attached rigidly thereto (Fig.6). The rest of the spokes 13, which are hinged to the disk 14 and connected both with each other and to the spoke 13a by pairs of the levers 18 hinged to each other, are also rotating while swinging relative to the axis of their articulated joint with the disk 14. This takes place owing to that the rolls 19, which are mounted on the axles of the hinges connecting the pairs of the levers 18, are rolling along the inner edge 21 of the central ring 20, thus moving nearer to the axis of the shaft 15 or, else, father therefrom so that, as a result, the angle between the levers 18 gets changed in each of their pairs. The profile of the inner edge 21 of the central ring 20 is designed so that, at any angular position of the disk 14, the angle between the adjacent spokes is at its maximum within the upper part of the relief drum 2, whereas this angle is at its minimum within the lower part of the relief drum 2. As a result, the distance between the adjacent beams 10 attached to the spokes 13 and carrying the holders 12 of the casing 3 changes gradually, in the process of turning the disk 14 through one revolution, from its maximum within the upper part of the relief drum 2 to its minimum within the lower part of the relief drum 2 and then again to its maximum as this one revolution of the disk 14 is being completed. Thus, within one revolution of the disk 14, the plates 4 get gradually displaced inside the casing 3 arranged on the holders 12 in the tangential direction from the position, when they define an essentially smooth surface (within the upper part of the casing 3), to the position, when they define a corrugated surface with the maximum height of the crimps (within the lower part of the casing 3), and back again to the position, when they define an essentially smooth surface.
Simultaneously with this, the mutual displacement of the plates 4 takes place in the direction that is parallel with the axis of the shaft 15; in this case, the dependency of such displacement from the angle of rotation of the disk 14 is similar to the dependency of the mutual displacement of the plates in the tangential direction, which has been described herein above. The displacement of the plates in the axial direction takes place in the following way.
As it has been already described herein above, while the disk 14 is rotated, the beams 10 attached to the spokes 13 are rotating too. In doing so, each of the rollers 22 mounted on each one of the outermost sliding members 1 1 of every beam 10 is in contact with the surface of the corresponding side ring 25. Since the rings 25 are arrange on the immovable support having an inclination relative to the vertical plane, in which essentially lies the central ring, the rollers 22 of every beam 10 are periodically moving nearer to one another and then back away from one another during rotation of the disk 14. In doing so, the distance between the adjacent sliding members 1 1 of every beam 10, which carry the holders 12 of the casing 3, gets also changed, because these sliding members are interconnected with each other by means of the pantograph 23. The inclination of the side rings 25 is selected so that the maximum distance between the adjacent sliding members 1 1 would correspond to the maximum distance between the beams 10, whereas the minimum distance between the adjacent sliding members 1 1 - to the minimum distance between the beams 10.
Thus, when the relief drum 2 is rotated, its shaping surface (the surface of the casing 3) is smooth within its upper part and becomes a corrugated surface within its lower part.
Prepreg is fed onto the upper part of the rotating relief drum 2 in the form of sheet material, which is pressed against the surface of the casing 3 by means of the roll 6 of the holding-down device 5. Preferably, use is made of glutinous prepreg, which adheres to the surface of the casing 3.
The value of adhesion is selected so that the sheet material 1 , when pressed against the casing 3 by the rolls 6, would not tear off from it, while the surface of the casing 3 is changed, thus repeating the shape thereof, but as soon as the relief drum is turned around through 180°, the corrugated sheet material 1 would detach from the surface of the casing 3 under the influence of its own weight. As the relief drum 2 continues to turn further on, the corrugated sheet material 1 moves in the direction away from the relief drum, while being at first supported by the supplementary roll 29a of the means 7 for removing the molded core and subsequently entering into the clearance between the rolls 29 of the upper and lower rows of the means 7 for removing the molded core. The above- mentioned clearance is to be set at a predetermined value, so that when the molded core passes between the rolls 29, the height of its crimps gets calibrated. The sheet material can be fed to the relief drum both in the form of a continuous band or as separate predetermined cut-off lengths.
Of course, various modifications may be made by a person skilled in the art to this invention, which has been just described, but only as its non-limiting examples.

Claims

1. A method of producing a core for a composite structural panel, said method comprising the following steps:
- feeding prepreg in the form of sheet material to a smooth shaping surface;
- pressing said sheet material against said shaping surface;
- deforming the shaping surface to form zigzag crimps, so that said sheet material pressed against the shaping surface takes the form of a deformed shaping surface; and
- removing the molded core;
characterized in that:
- said sheet material is fed on a relief drum having a shaping surface formed by a casing of a substantially cylindrical shape, said casing provided with a plurality of similar flat rigid plates arranged in the form of parallelograms jointly coupled at their sides;
- providing adhesion of said sheet material to the shaping surface; and
- deforming the shaping surface of the relief drum by mutual movement of said flat rigid plates in the casing together with turning simultaneously said relief drum around its axis.
2. The method according to claim 1, wherein the plates are moved in two directions: along the elements of the cylinder determining the shape of the casing, and in the circumferential direction perpendicular thereto.
3. The method according to claim 1, wherein the sheet material is pressed against the shaping surface substantially at the half of the circumference of the cylinder base determining the casing shape.
4. The method according to claim 1 , wherein the step of removing the molded core further includes calibrating the formed crimps by height.
5. A relief drum for using in the method according to any of claims 1 to 4, said relief drum comprising: a shaping surface and a supporting structure, wherein said shaping surface is formed by a casing of a substantially cylindrical shape, said casing provided with a plurality of similar flat rigid plates arranged in the form of parallelograms jointly coupled at their sides; and said supporting structure comprising:
- a few beams arranged along the elements of the cylinder determining the shape of the casing and distributed along the circumference of the cylinder base, each beam being fixed on a spoke connected to a disk attached to a driving shaft rotatably mounted in an immovable support, wherein one of the spokes is rigidly bound to said disk, whereas the other spokes are arranged on the disk so that they can turn in the plane of the disk;
- holders of the casing arranged on the beam so that they can slide along the beams;
- a mechanism for a mutual angular displacement of the spokes; and
- a mechanism for a mutual displacement of the holders,
wherein said mechanisms are configured so that, within one turn of the shaft, an angle between the adjacent spokes and distances between the holders on the corresponding beams will change, and when the angle between the spokes is at its maximum, the distance between the holders on the corresponding beams is also at its maximum, but when the angle between the spokes is at its minimum, the distance between the holders on the corresponding beams is also at its minimum.
6. The relief drum according to claim 5, characterized in that the casing is a sandwich including three joined together layers, wherein the middle layer is formed by plates with clearances between their sides, and the two other layers are fluoroplastic films, so that the portions of the films covering said clearances essentially form a hinged joint of adjacent plates.
7. The relief drum according to claim 6, characterized in that said layers are joined together by gluing.
8. The relief drum according to any of claims 5 - 7, characterized in that the mechanism for mutual angular displacement of the spokes comprises:
- a few hinged pairs of levers with free ends in each pair being hinged to the two adjacent spokes;
- a roller attached to the axle of each hinge connecting a pair of the levers; and - a central ring having an outer edge and an inner edge and fixed on the immovable support so that the inner edge is in contact with said rollers, whereas its profile is egg-shaped.
9. The relief drum according to claim 8, characterized in that the mechanism for mutual displacement of the holders comprises:
- sliding members arranged on each beam and carrying the holders of the casing;
- rollers attached to each of the outer sliding members of each beam;
- a pantograph placed along each beam and comprising a few pairs of hinged intersecting levers, wherein the axles of the hinges coupling said intersecting levers are connected to the sliding members; and - two side rings fixed to the immovable support on both sides from the central ring so that the surface of each of the side rings facing the central ring is in contact with the roller arranged on the corresponding outer sliding member, whereas said surface is inclined relative to the plane, in which essentially lies the central ring.
10. An apparatus for producing a core of prepreg in the form of sheet material for composite structural panels, said apparatus comprising a forming device and a means for removing the molded core, characterized in that said forming device comprises a relief drum according to any of claims 5 to 9 and a holding-down device comprising rolls rotatably attached to a rigid frame and encompassing the casing of the relief drum essentially along a half of the circumference of the base of the cylinder determining the casing shape; whereas said means for removing the molded core comprises a frame with rolls rotatably attached to the frame and arranged in two rows opposite one the other, wherein their axes lie in two substantially parallel horizontal planes so that there is a clearance between the rolls of the upper row and the rolls of the lower row, said clearance corresponding to the predetermined crimp height of the molded core.
11. The apparatus according to claim 10, wherein the rolls of the holding-down device are configured so that their position relative to the casing of the relief drum can be adjusted.
12. The apparatus according to claim 10, wherein the means for removing the molded core comprises an additional roll located in the lower row of the rolls on the side facing the relief drum.
13. The apparatus according to any of claims 10 or 12, wherein the rolls of the means for removing the molded core are configured so that their position can be adjusted in a substantially vertical direction.
EP11869427.2A 2011-07-08 2011-07-08 Method and apparatus with relief drum for producing a core for a composite structural panel Withdrawn EP2729294A4 (en)

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HUE054649T2 (en) * 2017-05-18 2021-09-28 Philip Morris Products Sa Method and apparatus to form a rod for an aerosol generating article from a sheet of material

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US7029264B2 (en) * 2003-03-28 2006-04-18 The Procter & Gamble Company Forming structure for embossing and debossing polymeric webs
ITMI20041266A1 (en) * 2004-06-23 2004-09-23 Luigi Pecis AUTOMATIC MACHINE FOR THE PRODUCTION OF SHAPED LASTRIFORM ELEMENTS PARTICULARLY FOR PACKAGING THERMAL AND ACOUSTIC AND SIMILAR INSULATIONS
RU2317168C2 (en) * 2005-12-05 2008-02-20 Казанский государственный технический университет им. А.Н. Туполева, Apparatus for corrugating sheet material

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