ARTICLE

TECHNICAL FIELD

[001] Embodiments of the invention generally relate to a process and/or substrate for a composite article, possibly a two and/or three dimensional molded article.

BACKGROUND

[002] Targets facing many industries involve development of more efficient and improved products tailored e.g. to specific demands of the products during use.

[003] In the automotive industry, for example, due to environmental aspects of improving energy efficiency, it is an aim to reduce automobile weight since lighter cars take less energy to accelerate and reduce friction on the road. The aerospace industry for example is converting many airplane designs to include composite materials.

[004] Such demands have consequently led to an accelerated search for materials and processes for providing structural elements with high weight reduction potential. Such new light weighting solutions however should also provide, inter alia, opportunities for cost reduction, short cycle time, complex shape forming capabilities and potential suitability for recycling.

[005] Thermoplastic-based composites have been shown to offer great advantages in these respects. [006] However, the high viscosity of thermoplastic resins may require use of impregnation methods and subsequent forming operations, which raise issues with regard e.g. to preform integrity, handling and tooling.

[007] Parts with complex shapes, multiple functions and tailored structural properties can be manufactured e.g. in structural insert injection molding or compression molding processes using inserts such as unidirectional (UD) thermoplastic composite tape-pregs (tows) or organo-sheet(s) or stamped fabrics or 3D preform (Skeleton) or the like, which may be robotically placed separately into the tool.

[008] The structural insert molding process combines the design freedom and net-shape processing of injection or compression molding. Hence, loads may be introduced and distributed efficiently within the component, and at the same time, creep resistance, stiffness and strength may be increased while working with the same or a reduced cross-sectional area.

[009] However handling of the structural inserts including heating and placement into the mold has been found to be most challenging in terms of part uniformity under heat / during the injection process and inserting operation.

[010] In cases of 3D structural inserts, during manufacturing this may require an additional forming tool as well as multi axis robotic arm.

SUMMARY

[011] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope.

[012] An aspect of at least some embodiments of the present invention relates to a process, or a sequence of processes, which may be performed on a substrate for the creation of a two and/or three dimensional article. Preferably the article may be an at least partial thermoplastic article that further preferably may be made from several different substances (i.e. a composite structure). [013] In one option, an embodiment of a substrate of the invention may include a thermoplastic sheet, preferably a composite sheet, and one or more structural members placed and/or formed upon the sheet, to preferably be attached to the sheet by e.g. heat bonding. A sheet according to various embodiments of the invention comprises or is formed as a fabric having a 'weft 'and 'warp', respective, 'zero' and 'ninety' degree fiber arrangement, however in some cases different fiber alignments can be selected. In addition or alternately, the sheet may be of a woven fabric type and/or of a non-crimp fabric (NCF) type. In some embodiments, the sheet may also be of a non-woven fabric type. In preferred substrate embodiments, the one or more structural members may be located on the sheet to form a pattern, preferably a predefined pattern, which supports reinforcement on or of the article to be formed based on a prior calculated loads analysis.

[014] In at least certain embodiments, structural members formed and/located on a substrate may be configured to reinforce and/or enhance utility of an article formed by such substrate(s).

[015] Structural members according to various embodiments of the invention may be and/or include at least one of: a filament, a unidirectional (UD) tape, stamped fabrics, woven fabric, non- woven fabric, non-crimped fabric (or the like). Filaments in at least certain embodiments may include and/or be filled with discontinuous fibers or continuous fibers, possibly glass fibers, carbon fibers, optical fibers, metals possibly electrical conductive metals such as copper, (or the like).

[016] Such substrate may preferably be simpler to produce and substantially less complex and time saving to bring into a manufacturing shaping process, such as a molding process, in order to form an enhanced utility and/or reinforced resulting article.

[017] In at least certain embodiments, the structural members may be and/or include one or more filaments, wherein such structural members are configured for being placed onto a sheet, preferably a composite sheet, to form an embodiment of substrate. [018] Possibly such a filament may include continuous and/or discontinuous fibers.

[019] In an embodiment, filaments may be partially- impregnated or fully- impregnated, where in a non-binding example, a partially-impregnated embodiment may refer to presence of more than about one percent of voids within a filament, possibly between optional fibers present in a filament; and a fully-impregnated embodiment may refer to presence of less than about one percent of voids within a filament, possibly between optional fibers present in a filament.

[020] In the case of partially-impregnated filament, final and/or additional impregnation may be performed and/or induced during subsequent processing of a substrate including such structural member, such as during a molding and/or lamination process performed on the substrate.

[021] Embodiments of the invention may include a substrate comprising of a sheet, preferably a composite sheet, and at least one structural member, preferably a reinforcement element for providing areal reinforcement or local reinforcement or both to the substrate and/or to an article formed from the substrate. Such embodiments may provide reinforcement while minimizing the number of inserts required for producing an article with similar functionality and/or structural characteristics, consequently reducing production cycle time of such articles.

[022] Embodiments of the invention may include a process of providing a substrate embodiment and then processing the substrate to form an at least partial three dimensional article.

[023] Such process may thus result in formation of an enhanced structural two or three dimensional article embodiment, areal or locally reinforced two or three dimensional article embodiment, where e.g. the resulting created article may have a tailor made functional design. Pre-defined structural members, e.g. UD tapes, stamped fabrics woven fabric, non-woven fabric, non-crimped fabric and/or filaments may enable specific local enhancement of characteristics, possibly reinforcement characteristics, but not only reinforcement, where needed on a resulting formed article. In a non-binding example, enhancement of characteristics may include provision of electric conductivity (or the like) via such structural member.

[024] In certain embodiments, pre-defined placement of the structural members on a sheet may be performed by at last one of: automated Tape Laying (ATL), automated fiber placement (AFP), a robotic arm, manual placement, an additive manufacturing device and/or a 3D printer device (or the like).

[025] In certain embodiments, filament type structural members, including continuous fibers or non-continuous fibers, may be partially-impregnated, preferably fully impregnated, with a thermoplastic matrix using e.g. a pultrusion process, a wire coating process or combinations thereof or other common methods or processes. Filament embodiments including continuous fibers may be in the form of rovings, yarns or a combination thereof (or the like).

[026] In at least some embodiments, filament type structural members including fibers, preferably continuous fibers, may be made of organic or inorganic matter or a mixture thereof. Some non-limiting examples of fibers may include: synthetic polymeric fibers (e.g. polyamide, polyester, polypropylene, polyurethane), ceramic fibers (glass, basalt), carbon fibers, metals, conductive fibers, natural fibers, optical fiber, Carbon nano tubes (CNT), Carbon nano tubes yarns / rovings and combinations thereof.

[027] Filament type structural members comprising fibers, preferably continuous fibers, in at least some embodiments may be in a bare form or may be pre-treated with an additional material or combination of materials to enhance the adhesion and/or impregnation and/or the geometrical accuracy of the later produced structural member on the substrate's sheet. Such materials may include silane, coupling agents, film formers, flow enhancers, binders, solvents, (or the like). In at least certain embodiments, such filament type structural members comprising fibers may be wire coated with other material to support the adhesion to the substrate. [028] Filament type structural members may in some cases be accurately calibrated into a predefined geometry, for example round cross section, triangular cross section (or the like).

[029] In at least some embodiments, a thermoplastics resin matrix for impregnation of a filament type structural member can be a polymer(s) of an olefinic or modified olefinic nature and its copolymers, amide or modified amide and its copolymer, polyester or modified polyester and its copolymers, styrenic based materials, polyurethane based materials, a mixture of thereof; and such thermoplastics resin matrix may amount to about 5-99.5 wt% of the total composite filament weight. In the case, e.g. of the thermoplastic resin matrix constituting 99.5 wt% - use of only 0.5 wt% of fiber content would be exhibited (e.g. conductive or optic fiber)

[030] In at least some embodiments, a thermoplastic resin matrix for impregnation of fibers of a filament type structural member may further include other additions, such as, but not limited to, anti- oxidants, processing aids, UV / light stabilizers, coupling agents, adhesion promoters, impact modifiers, colorants, reinforcing agents, fire retardants, filler and mixture thereof.

[031] In at least some embodiments, creation of a locally reinforced substrate may take place in an automated and/or semi- automated and/or manual process, placing the filament in a predefined pattern onto a sheet to achieve local enhancement of properties, such as reinforcement. Placement or forming of such structural members may be uni-directional, multi-directional, lattice shaped or any other form of 2D or 3D geometry.

[032] In at least some embodiments, placement or forming of a structural member on a sheet may take place upon heating of the structural members, preferably filament and/or filament matrix in a filament type structural member - to a point where same can be shaped and/or adhered to the sheet to form the substrate.

[033] In at least some embodiments, the conjugated substrate and application process ensures adhesion between the structural member and sheet in the substrate to an extent that enables consequent processes, such as, but not limited to, thermoforming, over-molding, injection, lamination, RTM (Resin Transfer Molding) and the like. In at least some embodiments, the extent of adhesion may be relatively weak, just sufficient to enable handling and placement of the substrate in a subsequent processing phase, e.g. molding phase.

[034] In at least some embodiments, the formed thermoplastic substrate including the sheet and structural member, may preferably be strongly adhered one to the other to effectively transfer and/or share loads applied on the substrate, in particular in the final formed two dimensional or three dimensional article, so that the loads are transferred into the sheet, possibly to reinforcing fibers of the sheet, and/or into the structural member, possibly filaments of the structural member that are formed on the sheet of the substrate.

[035] In at least some embodiments, the sheet of the substrate may or may not be a reinforced thermoplastic, with a thermoplastics matrix resin that can be made of polymers of an olefinic or modified olefinic nature and its copolymers, amide or modified amide and its copolymer, polyester or modified polyester and its copolymers, styrenic based materials, Polyurethane based materials, a mixture of thereof and may account of 5-95 wt% of the total composite weight of the sheet, or even a 100 wt% in a sheet including thermoplastic materials without any fibers, e.g. glass fibers.

[036] In at least some embodiments, the thermoplastic resin matrix of the sheet forming the substrate can further include other additions, such as , but not limited to, anti- oxidants, processing aids, UV/light stabilizers, coupling agents, adhesion promoters, impact modifiers, colorants, reinforcing agents, fire retardants, filler, Carbon nano tubes additive (CNT) and mixture of thereof.

[037] In at least some embodiments, the resultant composite substrate can be further utilized as a structural insert in the production of articles formed by at least one of: injection molding, compression molding, thermoforming processes, possibly resulting in laminated structures, sandwich structures further possibly having honeycomb geometries, or other moment of inertia amplifiers. The formed, preferably at least partially 3D shaped, article structure produced from a substrate including the sheet and structural member; may preferably be capable of bearing loads and effectively transferring it from the matrix to the reinforcing agent e.g. fibers.

[038] In at least some embodiments, thus, the invention may relate to a process and material composition for the creation of a locally reinforced 3D article structure including a pre-defined pattern of a structural member, preferably a composite filament, placed onto a thermoplastic sheet to form a substrate. The conjugated substrate may preferably later be formed into a 3D shape resulting in locally enhanced, preferably reinforced but not only, article having at least in part a thermoplastic body, possibly locally reinforced with a continuous fiber filament.

[039] In at least certain embodiments, enhanced utility provided by structural member(s) to a final produced article may be embodied in the structural members being used to convey or communicate signals within the article, such as electrical signals, optical signals, or the like. Structural members being made at least partially to include optical fibers and/or electrical conductive metals (or the like) may be used for providing such utility. By way of an example, a utility in a final article used in a car door may be to communicate via such structural members embedded within the article, electrical signals between two end units such as a lock and a toggle controlling the lock.

[040] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE FIGURES

[041] Exemplary embodiments are illustrated in referenced figures. It is intended that the embodiments and figures disclosed herein are to be considered illustrative, rather than restrictive. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying figures, in which:

[042] Fig. 1 schematically shows a substrate in accordance with an embodiment the present invention;

[043] Fig. 2 schematically shows a cross section of Fig. 1 taken along plane II- II marked in Fig. 1;

[044] Fig. 3 schematically shows a substrate generally similar to that in Fig. 1 after formation into an embodiment of an article of the invention;

[045] Figs. 4A and 4B schematically show cross sectional views of Fig. 3 taken along plane IV- IV marked in Fig. 3 illustrating various article embodiments of the invention;

[046] Fig. 5 schematically shows embodiments of a substrate and an article formed of or including the substrate;

[047] Fig. 6 schematically shows an embodiment of an article according to the present invention;

[048] Fig. 7 schematically shows another embodiment of a substrate according to the present invention;

[049] Figs. 8A and 8B schematically show yet another embodiment of a substrate and article, respectively, according to the present invention;

[050] Fig. 9 schematically shows possible processes that a substrate embodiment may undergo to form articles according to various embodiments of the invention; and

[051] Figs. 10 to 13 schematically illustrate various sheet embodiments in Figs. 11, 12B and 13; suitable for being draped over certain geometries in a resulting three dimensional shape and/or article.

[052] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated within the figures to indicate like elements.

DETAILED DESCRIPTION

[053] Attention is first drawn to Fig. 1 schematically illustrating a substrate 10 according to an embodiment of the invention, here seen including a sheet 12 and a structural member 14 formed/placed upon sheet 12.

[054] Structural member 14 may be formed/placed upon sheet 12, for example by a 3D printer, to form a configuration where sheet 12 and member 14 are at least partially attached to each other. Such attachment may be by heat bonding, adhesives (or the like) and may serve for providing a conjugated substrate embodiment that can be easily handled, e.g. during production, while maintaining a given pre-defined relative position of the structural member 14 on the sheet 12.

[055] In at least certain embodiments, materials of both the structural member(s) 14 and sheet 12 may be bonded to each other, by welding while melted material (e.g. PP) of the structural member(s) is in abutting (touching) engagement with the resin of the sheet. Preferably, a melting temperature applied to the structural member(s) and sheet should be high enough, e.g. above a softening point of the material of e.g. the sheet in order to ensure good bonding to the sheet. The softening point can be defined using at least one of: Vicat test, HDT, thermal analysis (or the like).

[056] In certain embodiments the sheet 12 may be heated up as well to support the adhesion, and in some embodiments the structural member(s) 14 may be pushed against the sheet and squeezed or rolled onto the sheet by a roller. In certain embodiments, surface treatment may be applied to the sheet to enhance bonding, for example by at least one of: corona treatment, plasma or other methods of increasing the surface tension (of the sheet, structural member or both) and remove silicones, dust or oils e.g. from the sheet's surface. [057] Structural member 14 may be any one of: a filament (F), a unidirectional (UD) tape, stamped fabrics (SF), woven fabric, non-woven fabric, non-crimped fabric (or the like). Filaments in at least certain embodiments may include and/or be filled with discontinuous fibers or continuous fibers, possibly glass fibers, carbon fibers, optical fibers, metals possibly electrical conductive metals such as copper, carbon nano tubes (CNT) yarns/ fiber (or the like). Sheet 12 may be a thermoplastic sheet, preferably a composite sheet, a fiber laminate (possibly glass fiber laminates), or the like. Different possible materials as herein described can be used to create the sheet, where such sheet according to various embodiments can be flexible or rigid at least when not heated.

[058] In Fig. 2, structural member 14 is shown in cross section to include a circular profile; however in other embodiments including structural members in the form of e.g. UD tapes, Stamped fabrics, woven fabric, non-woven fabric, non- crimped fabric; the structural member may have any other shape in cross section.

[059] Fig. 3 represents a view of an embodiment of an article 16 including a substrate, such as substrate 10 seen in Figs. 1 and 2. Article 16 may be formed in a preformed and/or manufacturing process in which a substrate such as substrate 10 is used or included. By way of an example, a substrate such as substrate 10 may be formed into a preform constituting an embodiment of an article 16 of the invention. Such preform type article may be further processed by for example injection over molding or compression over molding to assume a final state. In another example, a substrate such as substrate 10 may be inserted into a cavity of a mold (not shown) to be subjected to a molding process during which melted plastic that later solidifies is added over at least portions of the substrate.

[060] As seen in Fig. 3, article 16 may have combined two and/or three dimensional shapes, however in other embodiments such article(s) may be formed to have also strictly a two dimensional shape, or any other free-form shape.

[061] In the cross section seen in Fig. 4A, an embodiment of an article 16 is schematically shown including structural members 14 located at various geometrical locations of the article, some of which having a general two dimensional structure and others a three dimensional structure. In an embodiment, article 16 may include at least some structural members 14 at or along locations where a transition occurs in the geometry of the article, such as where one wall 21 or surface of the article extends initially upright from another wall 23 of the article possibly in a step-like manner.

[062] In the cross section seen in Fig. 4B, an embodiment of an article 16 is schematically shown illustrating possible ribs 18 (see enlarged view of rib 18 at top part of Fig. 4B) that are formed in the article. Such ribs 18 may be formed by molten material 17, such as plastic material, that has been added over the structural members 14 of the substrate during formation of the article 16. The molten material 17 may also be or include reinforced materials such as glass filed material(s) or mineral(s) filed material(s) - or the like.

[063] Ribs 18 may represent pre-defined areas in the article where structural support is designed to be added to the article, and provision of a substrate 10 with a pre-defined pattern of structural members 14 fixed on the substrate's sheet 12 - assists in precisely locating such members 14 in their designed location in the intended article 16.

[064] Attention is additionally drawn to Fig. 5 illustrating at the upper side an embodiment of a substrate 10 and at the lower side an embodiment of an article 16 formed or including the substrate. Substrate 10 includes a sheet 12 and structural members 14 fixed to the sheet in a pre-defined pattern. In article 16, the structural members 14 of sheet 10 are configured to be placed within the ribs 18 to provide structural support at these locations that are designed to provide support to article 16.

[065] Sheet 12, here at locations not including the structural members 14, may be designed to be placed or located within surfaces 20 of the article 16 that are outside of the ribs 18 in order to possibly provide enhanced characteristics to these surfaces, such as enhanced structural support. [066] The relative fixed location of the structural members 14 upon sheet 12 facilitates handling of the substrate 10 during manufacturing processes of the article (such as when substrate is inserted into a mold) so that a precise location of essential portions on the substrate, e.g. the structural members 14, within article 16 is more accurately and easily obtained.

[067] Attention is drawn to Fig. 6 illustrating a possible embodiment of an article 16 in which at least part of a structural member 14 of the substrate forming or included in the article remains revealed outside of the ribs 18 of the article. The revealed portion(s) of the structural member 14 may be either overlaid by material used during the manufacturing process forming the article (e.g. overlaid by plastic material) or may substantially remain as in their state in the substrate prior to manufacturing.

[068] Attention is drawn to Fig. 7 illustrating an embodiment of a substrate 10 including a sheet 12 and an at least partial three dimensional structural member 14 that extends away from the sheet. The structural member 14 may be fixed to the sheet in such embodiments at portions of the member 14 that meet and contact the sheet while other portions that extend above the sheet remain unattached to the sheet. The structural members 14, where they project above the sheet, may be designed to be located within plastic material in a resulting article made or including such substrate.

[069] Attention is drawn to Figs. 8A and 8B illustrating embodiments of a substrate 10 (Fig. 8A) and an article 16 (Fig. 8B) possibly formed from this substrate. Substrate 10 in Fig, 8 A being shown in a perspective top view and article 16 being shown in cross section showing part of the article formed by the substrate 10 of Fig. 8A. Substrate 10 here includes a sheet 12 and an at least partial three dimensional structural member 14 configuration that extends away and/or above sheet 12. Structural member 14 is here illustrated in an optional configuration for being located within a rib 18 (seen in Fig. 8B) that is designed to extend a height H above sheet 12 that is substantially larger in extension than a typical diameter of a structural member (or extension of a structural member in the height direction). Such ribs 18 may be formed by molten material 17, such as plastic material, that has been added over the structural members 14 of the substrate during formation of the article. The molten material 17 may also be or include reinforced materials such as glass filed material(s) or Mineral(s) filed material(s) - or the like.

[070] Here three such structural members 14 are illustrated laid one on top of the other in rib 18, with possible supporting struts 144 (possibly similar in material and configuration to the structural members 14) extending in contact (e.g. heat bonding contact) with the structural members 14 and sheet 12. Such struts 144 may be provided in substrate 10 for supporting the 3D configuration of the structural members 14 until placed in a subsequent processing stage for forming article 16.

[071] Attention is drawn to Fig. 9 schematically illustrating a possible production flow that may be used for forming an article 16. Starting at the top of the figure, in a first possible step a sheet 12 and a structural member 14 may be combined to form a substrate 10. The structural member 14 as illustrated in this example may be in the form of a Stamped Fabric (SF), woven fabric, non-woven fabric, non-crimped fabric, a Unidirectional tape (UD) and/or a Filament (F).

[072] The substrate may then be processed (when following the right downward directed arrow) to form a pre-form type article 16 that can later be further processed, for example in an injection or compression molding process to assume a final state of the article. Alternatively, in this example, the substrate 10 may be directly processed (when following the left downward directed arrow) for example in an injection or compression molding process to produce an article 16.

[073] Attention is drawn to Figs. 10 and 11 illustrating an aspect of at least certain embodiments of the present invention, that is aimed at addressing, inter alia, "drapability" of sheets i.e. the degree to which a sheet e.g. made as a fabric can be draped. Fig. 10A illustrates a sheet 12, for example, made of a woven fabric based composite, that is configured to be draped upon a deep 3D or varying geometry shape 19 (such as a geometry defined by a press, a mold, injection molding, compression molding, injection-compression molding, hot forming, vacuum forming, three dimensional forming, utilizing heat and/or pressure, or the like) in order to form therewith, e.g. after formation in a mold or press (see Fig. 10B) a resulting article 160.

[074] In the shown example seen in Fig. 10B, the forming of article 160 leads to movements in the fabric (i.e. "Fibers displacement", "Fibers undulation" and/or "Fabric distortion") - e.g. in weft and warp fibers and openings 25 created in high loads areas where the geometry of article 160 varies relatively sharply, here in the height direction.

[075] Attention is drawn to Figs. 11 A and HOB, illustrating an embodiment of a sheet 120 that in at least certain circumstances may be adapted to better handle such varying geometries in a resulting article 160. Sheet 120 is here illustrated including sheet patches 121, 122, 123 that are laid to overlap at least partially one upon of the other.

[076] Such placement is patches in at least certain cases may be determined according to areas in the resulting article 160 where openings (such as openings 25 seen in Fig. 10B) are predicted to occur. In at least certain embodiments, such areas where openings are expected to occur may be defined using drapeability simulation or actual trials.

[077] Sheet 120 preferably ensures that each patch will cover defined specific areas in article 160 with smooth and easy curves all in one operation. Sheet 120 may be used as a single insert into a tool where article 160 is adapted to be formed, such as a mold cavity. Overlapping regions 27 between patches may be provided in order to ensure suitable coverage of varying geometries in teh resulting article 160.

[078] Attention is drawn to Fig. 12A illustrating a single sheet being used to drape a geometry, where areas where high stresses are configured to occur in the sheet are here illustrated by the dashed arrows. In Fig. 12B, a sheet according to an embodiment of the invention including more than one patch, here three patches, is illustrated being configured to be draped over the same geometry as in Fig. 12 A, however here the provision of the patches, illustrate where marked by the dotted arrows, areas where bending is configured to be more easily facilitated, in particular in areas where curvature of the resulting shape is configured to be relatively high.

[079] With attention drawn to Fig. 13, a sheet embodiment 1200 is illustrated where a local patch 1201 is seen located over a base patch 1202 of the sheet, in a position where a predicted opening and/or high curvature in a resulting article is configured to occur. Such position may be determined e.g. using drapeability simulation or actual trials. Such patch 1201 may be formed as part of the sheet 1200 and after pre heating prior to being draped to extend along a required geometry, may be formed more easily with substantial less stresses than in stresses occurring in the base patch 1202.

[080] In at least certain embodiments, a multi-patched sheet, such as sheets 120 and 1200 illustrated in Figs. 11, 12B and 13; may be formed to include structural members according to the various embodiments discussed herein above, to thereby form substrate embodiments generally similar to those also described herein, that by virtue of the structural members added thereto, may have increased utility and/or rigidity e.g. in a resulting formed article.

[081] In the description and claims of the present application, each of the verbs, "comprise" "include" and "have", and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements or parts of the subject or subjects of the verb.

[082] Furthermore, while the present application or technology has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and non- restrictive; the technology is thus not limited to the disclosed embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art and practicing the claimed technology, from a study of the drawings, the technology, and the appended claims. [083] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures can not be used to advantage.

[084] The present technology is also understood to encompass the exact terms, features, numerical values or ranges etc., if in here such terms, features, numerical values or ranges etc. are referred to in connection with terms such as "about, ca., substantially, generally, at least" etc. In other words, "about 3" shall also comprise "3" or "substantially perpendicular" shall also comprise "perpendicular". Any reference signs in the claims should not be considered as limiting the scope.

[085] Although the present embodiments have been described to a certain degree of particularity, it should be understood that various alterations and modifications could be made without departing from the scope of the invention as hereinafter claimed.