Floor panel for forming a floor covering

Abstract

A floor panel is of synthetic material and forms a layer-shaped substrate with first and second pairs of opposite edges. The first pair of opposite edges has coupling parts forming a first mechanical locking system, which, in a coupled condition of two of such floor panels, effects a locking in the plane of the floor panels and perpendicular to the respective edges, and forms a second mechanical locking system, which, in a coupled condition of two of such floor panels, effects a locking transverse to the plane of the panels. The coupling parts on the first pair of opposite edges are realized substantially in the material of the floor panel itself. The floor panel is provided with an edge configuration on the second pair of edges allowing two of such floor panels to be positioned with their respective edge alongside each other and free from mechanical horizontally active locking systems.

Claims

1. A panel for forming a covering, wherein the panel substantially is realized on the basis of a synthetic material substrate, wherein the panel is rectangular, either oblong or square, and comprises a first pair of opposite edges and a second pair of opposite edges, wherein the panel, on the second pair of edges, is provided with an edge configuration arranged for two of such panels to be coupled with respective edges thereof, wherein the edge configuration of the second pair of edges is configured such that in the coupled condition at the second pair of edges a locking of the two of such panels is provided in the direction perpendicular to the surface of coupled panels, wherein the configuration of the edges is free from mechanical active locking systems in the direction parallel with the surface of the coupled panels and perpendicular to the coupled edges; wherein the second pair of edges comprises a first edge and a second edge; wherein the first edge consists a single protrusion projecting substantially perpendicular to the first edge, and said protrusion is the only protrusion of the second pair of edges; wherein the second edge consists a single undercut defined substantially perpendicular to the second edge, and said undercut is the only undercut of the second pair of edges; wherein in coupled condition of two of the panels at their second pair of edges, the protrusion of the first edge of the first of the two of the panels is correspondingly provided in the undercut of the second edge of the second of the two of the panels, such that a locking is provided in the direction perpendicular to the two of the panels; wherein the protrusion is shaped asymmetrically relative to a plane perpendicular to the surface of the panel.

2. The panel of claim 1, wherein the panel is a floor panel.

3. The panel of claim 1, wherein the substrate is layer-shaped, either single-layer or multi-layer.

4. The panel of claim 1, wherein the panel is bonded by means of adhesive means to an underlying surface.

5. The panel of claim 1, wherein at least one of the edges of the second pair of opposite edges comprises a bevel.

6. The panel of claim 1, wherein the panel at the second pair of edges, has an edge configuration which provides for that the actual panels extend along these edges alongside each other in an overlapping manner.

7. The panel of claim 1, wherein the second pair of edges is formed by profiled edge parts, which are realized in one piece of the substrate of the panel.

8. The panel of claim 1, wherein the first pair of edges is provided with an edge configuration which allows that two of such floor panels can be positioned with their respective edges adjoin each other exclusively by butt joint, wherein the configuration of the edges of the first pair of edges is free from mechanical active locking systems.

9. The panel of claim 1, wherein the panel is supple and resilient.

10. The panel of claim 1, wherein the panel substantially is composed of a thermoplastic material.

11. The panel of claim 1, wherein the panel comprises one or more basic layers and at least one top layer.

12. The panel of claim 1, wherein the substrate comprises plasticizers.

13. The panel of claim 1, wherein the substrate comprises fillers.

14. The panel of claim 1, wherein the substrate comprises chalk or lime as fillers.

15. The panel of claim 1, wherein the panel is less than 5 millimeter thick.

16. The panel of claim 1, wherein the protrusion comprises a symmetry.

17. The panel of claim 1, wherein the dimension of the protrusion, according to a direction perpendicular to the surface of the panel, declines in the direction away from the first edge and parallel with the surface of the panel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) With the intention of better showing the characteristics of the invention, herein below, as an example without any limitative character, some preferred embodiments are described, with reference to the accompanying drawings, wherein:

(2) FIGS. 1 to 22 are schematic representations of floor panels and their edge portions, wherein these schematic representations illustrate various embodiments of the first aspect of the invention;

(3) FIGS. 23 and 24 illustrate two embodiments of the second aspect;

(4) FIG. 25 illustrates the third aspect of the invention;

(5) FIGS. 26 to 30 illustrate various embodiments according to the fourth aspect of the invention;

(6) FIGS. 31 to 33 schematically represent portions of three floor panels which are realized according to the fifth aspect of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

(7) The figures are schematic representations which are self-evident. Herein, the figures, such as mentioned herein above, relate to five aspects, which also have been explained in the introduction. The general references P1 and P2 in the figures refer to the first pair of edges and second pair of edges, respectively. Reference A schematically represents an adhesive means or the like, whereas reference Z refers to locating edges.

(8) The various cross-sectional views substantially have the purpose of visualizing the principles of the locking in certain directions or not locking in certain directions.

(9) So, for example, FIGS. 1 to 3 represent three principal possibilities of interconnecting edges of the first pair P1, whereas FIGS. 5 to 22 represent a number of principal possibilities for the second pair P2. FIG. 2 thus forms a cross-section according to line II-II in FIG. 1, whereas the FIGS. 3 and 4 represent variants thereof. FIG. 5 is a cross-section according to line V-V in FIG. 1, whereas FIGS. 6 to 22 are variants of this cross-section.

(10) Herein below, the various aspects of the invention will be explained in greater detail.

(11) The first aspect is explained herein below by means of FIGS. 1 to 22, which schematically represent some examples.

(12) According to this first aspect, the invention relates to a floor panel 1 for forming a floor covering 2, wherein this floor panel 1 is realized substantially on the basis of synthetic material and preferably as a layer-shaped, either single-layer or multi-layer, substrate 3; wherein this floor panel 1 is rectangular, either oblong or square, and thus, as indicated in FIG. 1, comprises a first pair of opposite edges P1 and a second pair of opposite edges P2. The first pair P1 is formed by the edges 4 and 5, whereas the second pair P2 is formed by the edges 6 and 7.

(13) Still according to the first aspect, the first pair of opposite edges 4-5, as in the examples of FIGS. 2 and 3, comprises coupling parts 8-9, which allow that a plurality of such floor panels 1 mutually can be coupled to each other; wherein these coupling 8-9 parts form a first mechanical locking system and a second mechanical locking system. The first mechanical locking system is of such kind that, in a coupled condition of two of such floor panels, it effects a locking in the plane of the floor panels and perpendicular to the respective edges, in other words, provides for a horizontal locking, wherein the shifting apart of the floor panels according to a direction transverse to their edges is counteracted. The second mechanical locking system is of such kind that, in a coupled condition of two of such floor panels, it effects a locking transverse to the plane of the panels, in other words, provides for a vertical locking. Herein, the coupling parts, on the first pair of opposite edges, preferably are realized substantially in the material of the floor panel itself, and more particularly in said substrate 3.

(14) It is noted that such coupling parts 8-9, which in coupled condition provide for a mechanical locking in horizontal as well as vertical direction, can be realized in different manners and are not limited to the embodiments of the FIGS. 2 and 3. The embodiments of FIGS. 2 and 3, however, will be explained below in a short version.

(15) According to FIG. 2, coupling parts 8-9 of the first pair of opposite edges are configured such that two of such panels 1 on these edges can be coupled to each other by means of a turning movement R. In the example, the coupling parts 8-9 on the first pair of opposite edges to this aim consist of a tongue 10 and a groove 11, as well as of locking parts 12-13, which, in the coupled condition, prevent the shifting apart of the tongue and groove. Herein, the groove 11 preferably is bordered by an upper lip 14 and a lower lip 15, which latter in distal direction reaches farther than the upper lip, in other words, protrudes to beyond the upper lip. The locking part 12 is situated on the lower side of the tongue, whereas the locking part 13 is formed on the protruding part of the lower lip 15.

(16) It is noted that, in the case that, as aforementioned, the first pair of opposite edges is configured such that two of such panels 1 can be coupled to each other at these edges by means of a turning movement R, it is preferred that the second pair of edges is configured such that successively floor panels simply can be installed via a fold-down principle, such as further will become clear from the description of the second pair of edges. In the present application, by the “fold-down principle” must be understood that, when a newly to install floor panel is coupled to a preceding row of floor panels via said turning movement R, this movement also automatically has the final effect that the newly installed floor panel will arrive with its third or fourth edge in the intended end position in respect to the fourth or third edge of the preceding floor panel of the same row. According to the present patent application, the “fold-down principle” thus not necessarily implies that a vertical locking between the third and fourth edge of the adjacent floor panels must be achieved.

(17) FIG. 3 shows another possibility for the edges 2 and 3. Hereby, these edges are provided with coupling parts 8-9, which in this case, too, form a first mechanical locking system, which, in the coupled condition of two of such floor panels, effects a locking in the plane of the floor panels and perpendicular to the respective edges, as well as form a second mechanical locking system, which, in a coupled condition of two of such floor panels, effects a locking transverse to the plane of the panels; wherein these coupling parts, on the first pair of opposite edges, as represented, preferably are realized substantially in the material of the floor panel itself, and more particularly in said substrate. The specific characteristic of the coupling parts of FIG. 3 consists in that the respective edges 4 and 5 can be joined together by means of a downward movement M of one panel in respect to the other, this whereas therein a locking in horizontal as well as in vertical direction is achieved. Said first locking system, which provides for the horizontal locking, is formed in that the coupling parts 8-9 are realized as hook-shaped elements with locking parts 16-17, which engage behind each other as a result of the downward movement M. The second locking system, which provides for the vertical locking, is formed by locking parts 18-19, which hook behind one another, which engage behind each other by means of a snap action. It is noted that the locking parts 18-19, viewed in cross-section, can also be present on other locations on the coupling parts.

(18) In FIG. 4, a deviating embodiment for the coupling parts of the edges 4-5 is represented, to which will be returned further in de description,

(19) According to a characteristic of the first aspect of the invention, such floor panel is characterized in that the floor panel, on the second pair of edges, is provided with an edge configuration which allows that two of such floor panels 1 can be positioned with their respective edges 6-7 alongside each other, wherein the configuration of the edges is free from mechanical horizontally active locking systems. FIGS. 5 to 22, which are self-evident, represent various embodiments of edges 6-7 of the second pair P2 which fulfill this.

(20) According to a particular possibility of the first aspect of the invention, the second pair of edges is also free from mechanical vertically active locking systems. The embodiments of FIGS. 5 to 14 also fulfill this.

(21) In FIG. 5, an embodiment is represented wherein the floor panel, on the second pair of edges 6-7, has an edge configuration which provides for that the actual panels in installed condition extend along these edges in a non-overlapping manner alongside each other, more particularly can adjoin each other exclusively by butt joint.

(22) In FIGS. 6 to 9, embodiments are represented wherein the floor panel, on the second pair of edges, has an edge configuration which provides for that the actual panels extend along these edges 6-7 alongside each other in an overlapping manner, thus for embodiments which also are characterized in that the edge configuration of the second pair of edges is entirely free from locking systems, thus, also is also free from other locking systems than mechanical locking systems, such as adhesive means or the like.

(23) As represented in FIGS. 6 to 9, the overlapping preferably is realized by means of an upper flange 20, which, partially or completely, overlaps a lower flange 21, wherein the upper flange 20 preferably rests on the lower flange 21.

(24) FIG. 6 represents an example with flanges 20-21, which come into mutual contact via inclined surfaces.

(25) Preferably, however, use shall be made of flat flanges. FIGS. 3 to 7 are three examples thereof.

(26) It is noted that the flanges 20-21 preferably have a thickness which is larger than ⅓ of the overall thickness of the floor panel.

(27) FIGS. 6 to 8 illustrate that the flanges can be realized in one piece. According to an alternative, which is represented in FIG. 9, the lower flange forms part of a separate part 22, for example, in the form of a strip, which is attached to the floor panel, in this case in a recess 23.

(28) The embodiments of FIGS. 7 to 9 also illustrate that, seen in cross-section, the overlapping extends over a distance D which is larger than the overall thickness of the floor panel.

(29) As represented in FIGS. 8 and 9, a space 24 can be present at the bottom side, distally from the lower flange 21. Alternatively, no space is present, such as in the embodiment of FIGS. 6 and 7.

(30) In general, the overlapping indeed shall be realized such that the floor panels in installed condition adjoin against each other in the proximity of their upper edges.

(31) In FIGS. 10 to 14, some embodiments of the first aspect of the invention are represented, wherein the edges 6-7 also are free from mechanical vertically active locking parts, however, wherein indeed use is made of an adhesive means A, which realizes a connection between the edges. Herein, this relates to an adhesive means which is already present on the floor panels beforehand. In the represented examples, the adhesive means A beforehand is present on one edge; however, it is clear that instead thereof, it might also be present on the other edge or may even be present on both edges. In the latter case, it is preferred that in the installed condition, the adhesive means come into contact with each other.

(32) In FIG. 10, the edges 6-7 have a non-overlapping form, and an adhesive means A is present on the side of one edge. FIG. 11 represents a variant, wherein the adhesive means A is provided in a seat 25 at the bottom and protrudes beyond the edge of the floor panel and in this manner a subsequent floor panel, during the installation thereof, can come into contact with this adhesive means A.

(33) FIGS. 12 to 14 represent embodiments which fulfill the first aspect of the invention, however, therein also make use of an overlapping configuration, combined with the presence of adhesive. In the embodiments of FIGS. 12 and 13, the adhesive means A is present on the lower flange 21. In FIG. 13, a separate part 22 is applied, analogous to FIG. 9.

(34) In FIG. 14, an embodiment is represented wherein the overlapping is realized in that on one of the edges of the second pair of edges a protruding flap 26 is provided, which is attached to the lower side of the floor panel 1. The adhesive means A is present on the lower flange. The protruding flap is formed as a strip of a foil-like or film-like material and is attached to the lower side of the floor panel, for example, also by means of an adhesive, for which purpose possibly the same adhesive means A can be applied.

(35) According to a not represented alternative, such lower flange also may be formed by a foil which is present on the lower side of the floor panel in an uninterrupted manner, for example, a backing layer which extends farther than the substrate itself.

(36) As explained in the introduction, various types of adhesive can be applied for the herein above-mentioned adhesive means A; however, preferably use is made of a pressure-sensitive adhesive or glue.

(37) FIGS. 15 to 22 represent various embodiments of the first aspect of the invention, wherein the second pair of edges 6-7 now indeed is provided with a vertically active locking system, which is formed by mutually cooperating locking parts 27-28. Preferably, however, not necessarily, this relates to locking parts which can be forced into their coupled condition simply by deformation, such that an installation by fold-down remains possible.

(38) FIGS. 15 to 17 show embodiments without adhesive means, whereas FIGS. 18 to 22 provide for embodiments which indeed make use of adhesive means A.

(39) In a particular deviating embodiment of the first aspect, this is characterized in that on the first pair of edges the aforementioned second locking system is absent and preferably the coupling parts are realized exclusively from a so-called drop-in system, whether or not combined with an adhesive means. FIG. 4 represents an example hereof. It is clear that all herein above and herein below described coupling parts for the second pair of edges can also be applied in the same floor panel in combination with such drop-in system on the first pair of edges.

(40) As is evident in FIG. 1, it is preferred that the floor panel is rectangular and oblong and that the aforementioned pair of edges is formed by the edges which form the long sides, and the second pair of edges is formed by the edges which form the short sides.

(41) FIGS. 23 and 24 illustrate two embodiments of the second pair of edges 6-7 of floor panels which are realized according to the second aspect of the invention. De mechanical locking in horizontal direction herein is obtained by locking parts 29-30, which engage behind each other.

(42) In FIG. 23, a drop-in system is applied, whereas in FIG. 24 a so-called push-lock system is applied. In a drop-in system, there is no vertical locking. In a push-lock system, there is a vertical locking indeed.

(43) FIG. 25 shows an example of the second pair of edges of a floor panel which is realized according to the third aspect of the invention, wherein the intended locating edges are realized as Z.

(44) FIGS. 26 to 30 illustrate the fourth aspect of the invention for oblong floor panels 1. On the second pair of edges P2, now, as represented in FIG. 27, coupling parts are applied which allow a coupling by means of a turning movement. On the first pair of edges, coupling parts are applied selected from coupling parts of the drop-in type, push-lock type or of the type with overlapping portions with adhesive means, in such a manner that such floor panel first can be coupled on an edge of the second pair to a preceding floor panel in the same row and subsequently, via a downward movement, can be coupled with an edge of the first pair to one or more floor panels of a preceding row, this latter preferably by means of a rolling movement RM. Examples of the aforementioned three types of coupling parts are represented in FIGS. 28, 29 and 30, respectively.

(45) Finally, FIGS. 31, 32 and 33 show three embodiments of edges which are equipped with “velcro”-type fastening parts and which are suitable for application in a floor panel according to the fifth aspect.

(46) In the embodiment of FIG. 31, use is made of “velcro”-type fastening parts 31, die make use of a plurality of small separate “velcro”-type fastening elements.

(47) In FIG. 32, use is made of at least one “velcro”-type fastening part with a plurality of profile-shaped “velcro”-type elements.

(48) In the embodiment of FIG. 33, the “velcro”-type fastening parts are formed in one piece in the material of the floor panel.

(49) As becomes evident from the examples, it is generally preferred that the “velcro”-type fastening parts are active between overlapping flanges. Preferably, no other mechanical vertically active locking systems are applied therewith. Moreover, it is also preferred that no other horizontally active locking systems are applied therewith. For the first pair of edges, preferably coupling parts are applied of the type such as in FIG. 2 or 3, thus, coupling parts which can be joined into each other by a turning movement R or a downward movement M.

(50) It is clear that according to the invention primarily decorative floor panels are concerned, thus, with a decorative upper side, for forming a floor covering on an existing supporting floor, and more particularly for forming a floating floor covering.

(51) The invention is in particular intended for floor panels which substantially consist of synthetic material, or which comprise at least one or more basic layers on the basis of synthetic material, and more particularly with floor panels of the supple type.

(52) Still more particularly, the invention shows its advantages best with vinyl panels, in particular so-called vinyl tiles, and in particular with panels of the so-called LVT type (“Luxury Vinyl Tile”) or VCT type (“Vinyl Composite Tile”, also called “Vinyl Composition Tile”). Of course, also comparable panels of other synthetic materials, such as PU, are applicable.

(53) Such synthetic material floor panel, and in particular supple synthetic material floor panel, and more particularly such vinyl tile, preferably shows one of the following characteristics: the floor panel is substantially composed of one or more basic layers and at least a top layer, wherein the top layer as such may or may not be composed of a plurality of layers; herein, the top layer comprises at least a decorative layer, preferably in the form of a print, preferably provided on a foil or film; the top layer comprises at least a translucent or transparent wear layer; the floor panel is substantially composed of a thermoplastic material, preferably a soft thermoplastic material; the floor panel, or anyhow at least the one or more basic layers thereof, is/are substantially composed of polyvinyl chloride, more particularly of soft polyvinyl chloride, more particularly provided with plasticizers or the like; a composition “substantially” on the basis of PVC is to be interpreted broadly, as a large number of additives, for example, fillers, can be employed in PVC floors; the floor panel comprises at least one reinforcement layer, preferably formed of fibers, more particularly reinforcement fibers, such as glass fibers.

(54) It is noted that “soft PVC” is a term expressing that this relates to supple PVC, in other words, PVC which is relatively smoothly bendable. The term soft PVC is widely known in the technique. Such soft PVC consists of PVC which has been softened, preferably by means of a plasticizer added during the production process. Depending on the added amount of plasticizer, of course different degrees of suppleness can be achieved.

(55) By a plasticizer, any material must be understood which by being added results in a more supple PVC. Typical examples are phthalate plasticizers and isosorbide plasticizers.

(56) By PVC which is softened, of course also PVC can be understood or a composition on the basis of PVC, which as such has the feature of being supple, for example, in that it is modified.

(57) The same is valid for other “soft synthetic materials”, and the above is not limited to PVC.

(58) As already stated herein above, the present invention shows its advantages best when it is applied with floor panels which substantially are manufactured of supple or soft synthetic material, or in other words with supple panels.

(59) By supple floor panels, floor panels are intended, which panels, when they, in the case of a rectangular panel, for example, with a width of less than 50 centimeters, are clamped on one of the two short sides of the panel and herein protrude over a length of 100 centimeters and are not supported, will bend under the influence of their own weight, wherein this bending at the height of the free extremity in respect to the clamped extremity is minimum 10 centimeters. For this bending, a bending time of 10 seconds is taken into account, and wherein the panel starts from a flat horizontal position.

(60) The present invention is in no way limited to the embodiments described by way of example and represented in the figures; on the contrary, the floor panels of the aforementioned aspects can be realized according to various variants, without leaving the scope of the invention.

(61) So, the invention can also be applied, for example, with synthetic material-based floor panels which have a composed substrate, which panels also can be called hybrid floor panels. More particularly, this herein relates to a floor panel which consists at least of two substrate layers, each of a well-defined thickness, namely a first synthetic material-based substrate layer and a second substrate layer, situated there above, preferably directly there above, which second substrate layer has a thickness of at least 0.5 mm, preferably at least 1 mm; wherein this composed substrate, the floor panel concerned, respectively, also shows one of the following characteristics or any combination of these characteristics: the density of the first substrate layer differs from the density of the second substrate layer, and preferably the second substrate layer has a higher density than the first substrate layer; the first substrate layer is foamed, and preferably is of the closed cell type and still more preferably of the so-called hard foam type, and preferably the second substrate layer is not foamed or is less foamed than the first substrate layer; the first substrate layer is extruded in plate shape or is formed to a plate by means of a strewing process and consolidation of the strewn material; the second substrate layer consists of an extruded layer or of a layer which is formed by means of a strewing process and consolidation of the strewn material; the two substrate layers are glued to each other or, alternatively, are consolidated in the same production process, this latter, for example, by mutual direct adhesion among the materials of the substrates, or, for example, also by forming them of one composed mass with at least two layers;

(62) In preferred embodiments of such floor panel with a composed substrate, this further may have one or more of the following characteristics, wherein all not contradictory combinations of characteristics are possible: that the aforementioned first substrate layer comprises at least a thermoplastic material; that the aforementioned first substrate layer is realized at least on the basis of polyvinyl chloride, polyethylene, polyurethane, polypropylene or PIR, or a combination of the preceding; that the aforementioned first substrate layer is a filled synthetic material composite, wherein this filling preferably consists at least of one or of a combination of the following materials: bamboo, cork and/or wood, and more particularly one or a combination of the aforementioned materials in the form of chips and/or fibers and/or dust or powder, such as sawdust; that the aforementioned first substrate layer is foamed; that the aforementioned first substrate layer is of the closed cell-type; that the aforementioned first substrate layer comprises one or more plasticizers; that the aforementioned first substrate layer comprises fillers, such as chalk and/or limestone and/or talc; that the aforementioned first substrate layer is provided with at least one reinforcement layer, preferably of glass fiber or the like; that the aforementioned first substrate layer has a thickness of at least 3 mm, preferably at least 4 mm, and still more preferably at least 5 mm; that the aforementioned first and/or second substrate layer is realized water-resistant; that the aforementioned second substrate layer is based on synthetic material; that the aforementioned second substrate layer comprises at least a thermoplastic material, which preferably is of the soft type; that the aforementioned second substrate layer is realized at least on the basis of vinyl, such as polyvinyl chloride, more particularly soft polyvinyl chloride, polyethylene, more particularly soft polyethylene, polyurethane, polypropylene, PIR or a combination of the preceding; that the aforementioned second substrate layer substantially consists of one or a combination of the following materials: wood veneer, rubber, linoleum, a paper-based or foil-based laminate sheet, or alternatively any material, more particularly cork, bamboo or wood veneer, which is encased by vinyl or resin; that the aforementioned second substrate layer comprises one or more plasticizers; that the aforementioned second substrate layer comprises fillers, such as chalk and/or limestone; that the aforementioned second substrate layer is provided with at least one reinforcement layer, preferably of glass fiber or the like; that the floor panel comprises a backing layer, which preferably is situated directly underneath the first substrate layer, which backing layer, for example, is realized on the basis of one or more of the following materials: cork, rubber and/or a soft foamed layer; that the floor panel comprises a top layer, whether or not consisting of a plurality of layers, which preferably is situated directly above the second substrate layer, and/or that the second substrate layer is provided with a backing layer on the lower side of this second substrate layer; that the aforementioned top layer comprises at least a decorative layer, preferably in the form of a print, preferably provided on a foil or film; that the aforementioned top layer comprises at least a translucent or transparent wear layer and/or is provided with hard particles in order to increase the wear resistance, such as corundum; that the floor panel has an overall thickness which is smaller than 10 mm, still better in the order of magnitude of 8 mm, or possibly thinner; that the aforementioned first substrate layer is foamed gradually, wherein the degree of foaming increases in downward or in upward direction.