Guide rail of a guide system, guide system, method for manufacturing a guide rail and furniture

Abstract

Guide rail of a guide system (16) for a sliding element (3), in particular for a sliding element (3) of a piece of furniture (1) or a household appliance such as a kitchen appliance, wherein the guide rail is designed as a hollow profile enclosed by wall sections of the guide rail, wherein the wall sections comprise a horizontal wall section (23, 24) and two side wall sections (25, 26; 27, 28), wherein the horizontal wall section (23, 24) extends parallel and perpendicular to a longitudinal extension of the guide rail, wherein the side wall section (25, 26; 27, 28) extends parallel and perpendicular to the longitudinal extension of the guide rail, wherein the side wall sections (25, 26; 27, 28) are oriented at an angle to the horizontal wall section (23, 24), wherein the horizontal wall section (23, 24) and the two side wall sections (25, 26;27, 28) in a cross-section perpendicular to a longitudinal extension of the guide rail, at least section by section, form the three sides of a triangle, wherein the horizontal wall section (23, 24) defines a distal wall of the hollow profile, characterized in that the horizontal wall section (23, 24) forms a top and / or a bottom of the hollow profile.;

Description

State of the art Guide rails or guide systems for a drawer element, in particular a drawer element of a piece of furniture or a household appliance, such as a kitchen appliance, are known in different designs. For example, so-called partial extensions with two guide rails or full extensions with three guide rails are used as guide systems in an extension unit, whereby the rails can be moved telescopically relative to each other. Typically, a drawer element, such as a drawer, shelf, cooking tray, or the like, is slidably mounted on exactly two separate, identical partial-extension or full-extension runners. The respective runner runner unit is preferably attached to the inside of a furniture carcass or the housing of a household or kitchen appliance. Since a guidance system or guide rail must meet high technical and economic requirements, further optimizations in this regard are necessary. The state of the art is cited in DE 36 23 743 A1 and DE 20 2008 013 003 U1. Purpose and advantages of the invention The object of the present invention is to further improve the guides mentioned in the introduction and their provision, as well as corresponding furniture and household or kitchen appliances, in particular with regard to a comparatively high mechanical load-bearing capacity of the guide and its economical manufacture. In particular, material-saving and highly stable extension guides should be provided, which are especially space-saving and structurally advantageous and can also withstand high static and dynamic loads. This problem is solved by the independent claims. The dependent claims relate to advantageous variants of the invention. The invention initially relates to a guide rail of a guide system for a sliding element, in particular for a sliding element of a piece of furniture or a household appliance, such as a kitchen appliance, wherein the guide rail is designed as a hollow profile enclosed by wall sections of the guide rail, wherein the wall sections comprise a horizontal wall section and two side wall sections, wherein the horizontal wall section extends parallel and perpendicular to a longitudinal dimension of the guide rail, and wherein the side wall sections extend parallel and perpendicular to the longitudinal dimension of the guide rail, and wherein the side wall sections are oriented at an angle to the horizontal wall section. "Parallel and perpendicular" refers to the orientation of the plane of the respective flat main sides of the horizontal wall section and the side wall sections.The side wall sections protrude at an angle relative to the horizontal wall section on the same side. The guide rail consists primarily of thin sheet metal bent into its final shape. The invention relates in particular to a furniture guide rail or rail of a furniture partial extension or furniture full extension or a household appliance guide rail. The core of the invention lies in the fact that the horizontal wall section and the two side wall sections form, at least partially, the three sides of a triangle in a cross-section perpendicular to a longitudinal extension of the guide rail, wherein the horizontal wall section defines a distal wall of the hollow profile. The sections are accordingly designed with straight lines in cross-section. One, two, or all three corner areas of the underlying or imagined triangle in the cross-sectional view may deviate from the geometrically defined corner shape of the corresponding triangle. The corner areas, which are formed by two converging wall sections in cross-section, may touch at a corner or converge directly to the corner. The corner areas of the underlying triangle are preferably designed differently in the hollow profile, and / or there may be a gap free of material between the ends of two converging wall sections. A straight section of a wall segment may also be longer than a side of the considered triangle. The horizontal wall section and the two side wall sections are arranged, for example, in a triangular shape. This allows the guide rail to be manufactured with a comparatively small amount of material. Furthermore, comparatively high stability values ​​can be achieved with the guide rail according to the invention. In particular, the guide rail according to the invention is mechanically highly stable. The guide rail according to the invention is particularly stable against bending in its longitudinal extension or in the direction of the longitudinal axis and comparatively stable against deformation due to twisting or torsion about the longitudinal axis. The guide rail, with a cross-section that at least approximates a triangle in its basic form, is accordingly triangular in its basic shape, preferably with corner areas that are not pointed on the outside. The corner areas may, for example, have outwardly projecting sections. The corner areas that form between the horizontal wall section and the respective side wall section, and in the area where the two side wall sections meet or are adjacent, preferably have sections with a convex shape or with a rounded outer contour. The corner areas between the horizontal wall section and the respective side wall section, or their outer contour sections, are preferably, for example, loop-shaped. The hollow profile is preferably designed as a hollow profile that is completely closed over at least its essential length, for example in the form of a longitudinally closed tube with an approximately triangular cross-section or a longitudinally closed tube with an externally triangular shape. Preferably, an interior angle of between 30 and 70 degrees is formed between the horizontal wall section and a side wall section. Preferably, both side wall sections are angled at the same interior angle on the horizontal wall section. Accordingly, the three corner regions of the triangular shape of the hollow profile lie in the area of ​​the respective connecting section between the horizontal wall section and the respective side wall section, and in the area where the two converging ends of the two side wall sections approach each other. This corner region of the triangular shape, defined by the two side wall sections, lies on the opposite side from the center of the triangular hollow profile when viewed from the horizontal wall section.Preferably, the corner area defined by the two side wall sections lies on the normal to the horizontal wall section, which intersects the center line that, in the longitudinal extension of the horizontal wall section, divides it into two strips of equal width. The horizontal wall section, and thus an outer surface of the horizontal wall section, is at least substantially horizontally oriented in the operating state of the guide rail when the guide rail is installed in the completed guide system. The horizontal wall section, which is preferably strip-shaped in its basic form, extends with its two preferably parallel longitudinal edges along the length of the guide rail. The horizontal wall section spans between two end edges (or transverse edges) oriented perpendicular to the longitudinal edges and extending along the length of the horizontal wall section, and the two longitudinal edges of the horizontal wall section. The horizontal wall section has an outer surface whose area is preferably flat and even. Regarding the material or...The sheet thickness is spaced apart from the outside, and opposite it is an inner side of the horizontal wall section that defines the cavity of the hollow profile. Depending on the operating condition, the horizontal wall section can form either the bottom or the top side of the guide rail. The two side wall sections adjoin the horizontal wall section along its two longitudinal edges. At a first longitudinal edge of the horizontal wall section, a first side wall section adjoins the horizontal wall section directly or, preferably, via a connecting section at an angle. At a second longitudinal edge of the horizontal wall section, a second side wall section adjoins the horizontal wall section directly or, preferably, via another connecting section at an angle. Preferably, the first and second side wall sections are identical on the horizontal wall section or are angled at the same angle to the plane spanned by the horizontal wall section. Preferably, a side wall section is formed adjoining each of the two longitudinal sides of a horizontal wall section.Preferably, the horizontal wall section and the two side wall sections have at least approximately the same length or are preferably formed over the entire length of the guide rail. Each side wall section is preferably made of the same material as the horizontal section or formed integrally with it. Accordingly, the horizontal wall section and the first and second preferably strip-shaped side wall sections are made of a thin layer of material, preferably a sheet 0.5 to over 2 millimeters thick, more preferably a sheet between 0.8 and 1.2 millimeters thick. The sheet thickness of the guide rail is preferably uniform or identical throughout. The rail guide system formed by the guide rail is designed primarily as linear guides. In a partial extension, a component of the guide system comprises a cabinet rail that is fixed in position during use and can be attached to the cabinet side, and a movement or running rail that is movable relative to the cabinet rail during use, hereinafter also referred to as a sliding element rail. In a full-extension slide guide system, a cabinet rail, a drawer slide rail, and a center rail positioned between the cabinet rail and the drawer slide rail are present. Typically, sliding and / or rolling bearings are also provided for the relative movement of the rails within the assembly. The bearings acting between the rails include, for example, a carriage with one bearing element or, preferably, several bearing elements mounted on it, such as rolling bearing elements. The hollow profile is to be understood as a profile that encloses a cavity, at least circumferentially along its longitudinal axis, to a substantial extent, through wall sections of the profile, such as the horizontal wall section and the side wall sections, and optionally further wall sections. The cavity is preferably a material-free hollow volume that is bounded externally or radially to a central longitudinal axis of the guide rail, running centrally within the hollow volume, by the wall sections. The hollow profile is preferably open at its end face. Furthermore, the guide rail according to the invention provides spatially advantageously oriented running or support surfaces in a small space or in a compact manner for the storage of further components of the guide system, in particular for a further guide rail and / or bearing bodies of the bearing means of the guide system. The cavity, for example, has an approximate rod shape with a basic triangular or triangular cross-section. The horizontal wall section and the two side wall sections can form the guide rail on their own, or, for example, they can form an upper and / or a lower section of a guide rail. If, in addition to the triangular section of the guide rail, another section with a non-triangular shape is present, which is particularly advantageous in a full-extension guide system, this additional upper or lower section can also be designed as a profile, preferably a hollow profile, for example, a square profile, L-profile, or T-profile. Preferably in a full-extension guide system, the guide rail has an upper section and a lower section, wherein the upper and lower sections each have, according to the invention, a horizontal wall section and two side wall sections which are arranged in a triangular shape in a cross-section perpendicular to a longitudinal extension of the hollow profile, wherein the horizontal wall section defines a distal wall of the hollow profile. In a vertical direction relative to the orientation of the guide rail in its operational state, an intermediate section can be formed between the upper and lower sections of the guide system. This intermediate section can be formed, for example, by additional wall sections of the guide system oriented at an angle to the horizontal or side wall section and spaced apart in the width direction or perpendicular to the height. Alternatively, an intermediate section between the upper and lower sections can be omitted. For example, the upper and lower sections, preferably each with a triangular cross-section, can be directly connected to each other. Preferably, the guide rail is symmetrical, e.g., axially and / or mirror-symmetrical, as will be explained further below. Preferably, the horizontal wall section and the two side wall sections are formed in one piece, or they are formed from a continuous flat material by forming processes such as cold forming to create the final shape of the guide rail. A distal wall of the hollow profile formed by the horizontal wall section means that the wall section of the guide rail formed by the horizontal wall section has an outwardly facing outer surface, which forms the outermost surface of the guide rail in the relevant direction from its center. If necessary, narrow or small areas may exist laterally along the horizontal wall section of the guide rail, located further outward from the center than the flat outer surface of the horizontal wall section. Such an area is, in particular, a connecting section, formed, for example, by the transition between the longitudinal edge of the horizontal wall section and the respective side wall sections. The connecting section may, for example, have a bent section of material extending in the relevant direction.is located further away from the center of the guide rail, either upwards or downwards, than the horizontal wall section or its outer side. The above applies in principle, regardless of whether, in the usable state, the outside of the horizontal section forms a top or bottom side of the guide rail. Furthermore, it is advantageous that the wall sections include a connecting section, wherein the horizontal wall section and the side wall section are connected via the connecting section, wherein the connecting section has a support section and a bending section that is angled, in particular bent, at the support section, and wherein the bending section is angled or bent towards the support section to such an extent that the bending section and the support section enclose a bending angle in a range between 45 degrees and 180 degrees. This allows the guide rail according to the invention to be advantageously manufactured, in particular by means of an automated or machine-assisted bending process from a flat material such as a sheet metal strip. Accordingly, the side wall sections and the horizontal wall section are formed in one piece. Specifically, exactly two side wall sections are bent onto the horizontal wall section, one each adjoining the two longitudinal side edges of the horizontal wall section via a connecting section. The connecting section comprises the support section and the bending section. The connecting section has one or more bends or folds and, in cross-section relative to the length of the guide rail, is preferably U-shaped, ear-shaped, or groove-shaped with a curved, straight, or funnel-shaped section of the contour, for example, U-shaped, V-shaped, and / or polygonal. Preferably, the bent section connects to the horizontal wall section via a first bend. The bent section extends, for example, to a second bend, to which a first edge of the support section connects. The support section transitions into the side wall section at a second edge with a further bend, or the support section extends straight into the side wall section without any bend. The connecting section has an approximately loop- or ear-shaped cross-section. In particular, the connecting section projects slightly beyond the horizontal wall section or its outer surface. Preferably, the respective connecting section is identical along both longitudinal edges of the horizontal wall section. The triangular shape describes an approximate basic form of the guide rail according to the invention, which allows for different configurations of the connecting section between the horizontal section and the respective side wall section. The connecting section is preferably produced by a cold forming process, in particular by carrying out a bending and / or folding operation. Advantageously, the connecting section is formed as a longitudinal or elongated bead along at least the essential length of the horizontal wall section. However, a direct connection between the horizontal wall section and the side wall section without an intermediate section is also conceivable. Preferably, both side wall sections are connected to the common horizontal wall section in the same or identical manner. As previously explained, the connecting section can project outwards or distally, at least partially, beyond the horizontal wall section or the plane of the outer surface of the horizontal wall section. Conversely, the upper surface of the guide rail or the outer surface of the horizontal wall section can be slightly recessed along the normal to the horizontal wall section, reaching the highest point or the point furthest from the center of the guide rail of the connecting section. The connecting section preferably extends over the entire length of the horizontal wall section or the guide rail, particularly along both sides of the longitudinal edges of the horizontal wall section. Only short interruptions may be bent away at the connecting section to act as stops. According to the invention, the horizontal wall section forms a top and / or a bottom of the hollow profile. This is based on an orientation of the guide rail in the usable or installed state of the guide system on a piece of furniture or a household appliance such as a kitchen appliance. The spatial orientation of the guide rail in its operating state is such that the horizontal wall section forms either the top or bottom of the guide rail. If, in the operating state, the horizontal wall section is located above the downward-projecting side wall sections, then the horizontal wall section forms the top of the hollow profile. If, in the operating state, the horizontal wall section is located below the upward-projecting side wall sections, then the horizontal wall section forms the bottom of the hollow profile.To form a top and a bottom of the guide rail, each with a separate horizontal wall section, the guide rail or hollow profile comprises two subsections, each triangular in cross-section, consisting of a horizontal wall section and two angled side wall sections adjoining it. The cross-section of this hollow profile has an approximate outline resembling an hourglass or is dumbbell-shaped with a central constriction and two wider sections at the ends in the vertical direction.The constriction area, viewed in cross-section of the guide rail, is formed at least partially by the converging side wall sections along a common horizontal wall section, with or without an intermediate section adjoining the side wall sections that connects the two side wall sections of the upper horizontal wall section to the two side wall sections of the lower horizontal wall section. It is also conceivable that no intermediate section is present, in which case the converging ends of the two upper side wall sections are directly connected to the converging ends of the two lower side wall sections. Each horizontal wall section has a flat, outward-facing outer surface, which is horizontally aligned when installed. In the case of two horizontal wall sections forming the top and bottom, the top and bottom surfaces are aligned parallel, with their outer surfaces vertically spaced apart by a distance that essentially corresponds to the total height of the guide rail, apart from any minor additional heights due to the connecting sections, which together might, for example, constitute approximately 5% of the total height. A further advantageous modification of the invention is characterized in that the connecting section is designed such that one side of the bent section abuts the support section. This is a particularly advantageous design from a manufacturing and mechanical perspective. In particular, this abutment results in mutual support between the bent section and the support section. An inner side of the bent section abuts an inner side of the support section. Furthermore, this abutment provides material reinforcement or increased material thickness in the connecting section, thus increasing its mechanical stability. This is because a first layer of material is provided by the bent section and a second layer by the support section, resulting in a double layer structure in this section.The connecting section therefore preferably has curved material areas such as bent sheet metal sections of the originally flat sheet metal material. The bending section and the support section stabilize the guide rail, particularly against elastic deformation. For example, forces acting on the bending section can be absorbed by the support section, and vice versa. These forces occur, for instance, when the horizontal wall section and the side wall sections are loaded by the weight of the shear element or its load during use of the guide system. The increased stability of the guide rail advantageously acts in various spatial directions, for example, against deformation due to bending and / or torsion with respect to the longitudinal axis of the guide rail. Furthermore, it is advantageous that the guide rail is formed from a formed flat material. The flat material is, in particular, a strip or band material, preferably made of steel or sheet metal. The guide rail is preferably formed entirely from sheet metal, preferably by a cold forming process of a stamped flat material. It is also advantageous that the hollow profile is mirror-symmetrical in cross-section in two mirror planes, with the two mirror planes being perpendicular to each other. The mirror planes intersect, in particular, along the central longitudinal axis of the guide rail. A weld seam that may be present along one side of the guide rail can cause a slight deviation from absolute mirror symmetry with respect to one of the two mirror planes, which is insignificant in practice with regard to the variable, direction- and side-independent application possibilities. For example, the weld seam is present along the length of the guide rail on one side, particularly in the area of ​​the intermediate section, but not on the opposite side in the width direction.This is because the guide rail is preferably made from a flat material, the opposite longitudinal edges of which are welded together in the finished guide rail. Due to its mirror symmetry, the guide rail can be used for either a right- or left-hand guide system on a sliding element. Furthermore, each end of the two guide rails can form either the front or rear end of the guide system, depending on the operating state. In other words, assuming a horizontal longitudinal orientation, the guide rail can be used identically rotated 180 degrees from the horizontal, just as it can be used identically rotated 180 degrees from the vertical. In the area of ​​a weld seam of the finished hollow profile, before welding the material areas to be welded together, the material thickness of these material areas is reduced by preferably rolling with e.g. rollers to preferably 50 percent of the thickness of the remaining material areas, preferably to a reduced material thickness of approximately 0.3 to 0.5 millimeters or to approximately 0.4 millimeters. A further advantageous modification of the invention is characterized in that the wall sections have a vertical wall section, wherein the vertical wall section connects side wall sections to one another. The vertical wall section thus belongs to the intermediate section discussed above. If the guide rail comprises a first or upper rail section with a horizontal wall section and two angled side wall sections, and additionally comprises a second or lower rail section with a horizontal wall section and two angled side wall sections, then a first vertical wall section connects one end of an upper side wall section to one end of a lower side wall section opposite it in the vertical direction. In the operating state, the vertical wall section is preferably oriented vertically. It is particularly advantageous if another vertical wall section is present on the other side of the guide rail, connecting one end of the other upper side wall section with one end of the other lower side wall section. Preferably, the wall sections are designed such that mirror symmetry about two perpendicular mirror planes is maintained in this configuration as well. Advantageously, the guide rail comprises two opposing horizontal wall sections, each with two side wall sections, with the two vertical wall sections being located in a central section that is constricted or tapered on both sides. According to a further advantage of the invention, the support section is aligned parallel to a side wall section. There may be, for example, a slight offset between the support section and the side wall section. Preferably, there is no offset, so that the support section forms a seamless extension of a side wall section at an end section of the side wall section facing the horizontal wall section. An advantageous embodiment of the invention is characterized in that the bending section is aligned parallel to a side wall section, in particular parallel to a support section. Advantageously, the bending section lies flat against the support section or its inner surface with its inner or underside, so that the bending section and the side wall section are parallel. Preferably, the horizontal section and the bending section enclose an angle greater than 90 degrees, preferably an angle of approximately 130 to 150 degrees, preferably 140 degrees. It is also advantageous that the hollow profile in the area of ​​the connection section has a stop element acting in the longitudinal direction of the hollow profile. The stop element is formed, in particular, by a partially cut-out and bent section in the connection section, with the stop element projecting beyond the contour of the remaining guide rail. The stop element serves, in particular, to limit the longitudinal movement of the carriage of the bearing elements. Furthermore, it is advantageous that the horizontal wall section and / or the side wall section each form a contact surface for parts of the bearing arrangement over at least a partial length of the guide rail. Preferably, the respective outwardly facing flat or planar outer surfaces of the horizontal wall section and the side wall sections form a running surface for the corresponding rolling bearing elements that run or roll on the respective outer surface. The running direction is longitudinal to the guide rail. On the horizontal outer surface of the horizontal wall section in the operating state, i.e., in the case of two horizontal wall sections, on a horizontal upper surface and a horizontal lower surface of the guide rail, several cylindrical rolling elements, mounted on a carriage, preferably roll. In this way, essentially vertical bearing forces are absorbed. On the slanted, flat outer surfaces of the side wall sections, several cylindrical rolling bearing bodies of the carriage also preferably roll, which, in addition to transmitting bearing forces, also perform a laterally horizontal guiding function and a vertical guiding function transverse to the direction of travel. The invention further extends to a guide system for a sliding element, in particular a linear guide system for a sliding element of a piece of furniture or a household appliance such as a kitchen appliance, wherein the guide system comprises a unit with exactly two guide rails, the guide rails comprising a cabinet rail and a sliding element rail slidably mounted on the cabinet rail, wherein the sliding element rail is configured for connection with the sliding element, and wherein a carriage is provided between sections of the cabinet rail and the sliding element rail for relative movement of the cabinet rail and the sliding element rail, wherein the essential aspect of the invention lies in the fact that the cabinet rail is designed as a guide rail according to one of the embodiments described above. Preferably, the cabinet rail is designed as a closed hollow profile with a triangular cross-section in its basic form.The sliding element rail is preferably designed as a bottom-open profile that encompasses the triangular shape from above. Preferably, at least an inner section of the sliding element rail approximates the triangular shape, which is advantageous for a compact or nested rail design, with the associated carriage with bearing elements operating in a narrow gap between the rails. This provides a particularly stable partial extension guide system that is very resistant to bending and torsional forces while using comparatively little material. A bearing arrangement acting between the rails preferably comprises at least one carriage with several bearing bodies mounted on it, which run or roll along the horizontal wall section and both side wall sections during operation of the partial extension. Furthermore, the invention relates to a guide system for a sliding element, in particular to a linear guide system for a sliding element of a piece of furniture or a household appliance such as a kitchen appliance, wherein the guide system comprises a unit with exactly three guide rails, wherein the guide rails comprise a cabinet rail, a sliding element rail and a center rail, wherein the sliding element rail is designed for connection with the sliding element, wherein the center rail is provided between the cabinet rail and the sliding element rail, wherein a carriage is provided between sections of the cabinet rail and the center rail and a carriage is provided between sections of the center rail and the sliding element rail for relative movement between the rails, wherein the center rail is designed as a guide rail according to one of the embodiments described above.It is designed as a closed hollow profile with a basic triangular cross-section. In a full-extension drawer slide system, the slide system is preferably designed as an underfloor slide system. The drawer slide is designed so that the underside of the drawer bottom can rest on the slide when the slide system is in use. The drawer bottom is thus placed on top of the slide. The full extension and the partial extension can alternatively also be designed for accommodation, for example, in a cavity of a hollow chamber frame. Finally, the invention also extends to a method for manufacturing a guide rail according to one of the above-mentioned arrangements, wherein the guide rail is manufactured from a flat material, in particular from a strip material, and wherein the manufacturing of the guide rail is carried out by a continuous forming process of the flat or strip material. Preferably, a flat sheet metal or a comparatively easily cold-formable steel material is used as the starting material for its manufacture. Advantageously, the continuous forming process of the flat or strip material is carried out using a continuous roll forming process. The manufacturing processes are differentiated into six different methods according to DIN 8580, among which, in addition to joining, forming by pressure forming, and especially the continuous roll forming process, is suitable for the production of the guide rail. In this process, the strip material is continuously transported along a processing path and subjected to several continuous or sequential processing steps, such as forming by pressure elements like rollers. The rollers exert precisely defined compressive forces on the material to a predetermined degree and at specific points. This gradually deforms the material plastically in a defined manner until it reaches its final shape. Furthermore, other manufacturing processes are used in the production of the guide rail, sometimes in conjunction with continuous roll forming or in upstream or downstream processes, particularly bending. It is advantageous if, during the manufacturing of the guide rail, work hardening occurs at least in certain areas of the sheet metal material as a result of the forming process, leading to a beneficial change in the material properties. Advantageously, in a subsequent step to the continuous forming process of the flat or strip material, a weld joint is created between sections of the formed flat or strip material using a continuous laser welding process. In this continuous laser welding process along a linear weld line over the length of the formed hollow profile, it is advantageous that a consistently high or optimized weld quality is achieved across the entire weld seam. This is because, according to the invention, the continuous operation eliminates the entry and exit zones of the laser welding device that occur, for example, in a discontinuous or pulsed manufacturing process, which would lead to a correspondingly reduced weld quality. Furthermore, an advantage of the invention is given if the welding between sections of the formed flat material is carried out in such a way that the material thickness in the area of ​​the material to be welded is reduced compared to the remaining areas of the formed flat or strip material. If the guide rail is formed from a flat, strip-shaped sheet metal material by forming, which is preferred, the hollow profile will have at least one longitudinal or linear region along which the longitudinal edges of the formed sheet metal material extend. On the formed product, the longitudinal edges are preferably formed towards each other and are therefore close to each other or in contact, which has a mechanically stabilizing effect. Preferably, the two longitudinal edges of the sheet metal material on the formed hollow profile are butt-jointed, and preferably joined by a material bond or weld. The hollow profile or the wall sections of the hollow profile are accordingly preferably without a separation point or open seam, with a material-free gap along the longitudinal extent of the hollow profile. The gap width can be minimal, possibly even disappearing, which is achieved by contact of the edges against other sections of the hollow profile or preferably by mutual contact, e.g., by butt-jointing the narrow end faces of the edges. The edges of the formed sheet metal material rest against each other within the hollow profile, or are pressed against each other, exhibiting physical contact and preferably a material-bonded connection. This mutual contact of the edges is preferably present along the entire length of the hollow profile. Preferably, the longitudinal edges are connected to each other or to other sections of the guide rail along their entire length, preferably by a material bond, e.g., thermally bonded or welded. Preferably, the butt-jointed edges are welded together by a material bond over at least the substantial length of the edges. It is also possible that along the adjacent edges, some areas are connected to each other, while other areas are not, for example, materially bonded. For instance, the edges may be welded together at several spaced-apart points, whereas other areas are not welded or materially bonded, but are in contact with each other. Preferably, the welding between sections of the formed flat material is carried out such that the material thickness in the area to be welded is reduced compared to the remaining areas of the formed flat or strip material. This reduces the energy required for laser welding compared to welding with an unreduced material thickness. Furthermore, a welding device with a comparatively lower power output than the non-thickness-reduced edge area can be used, which is economically advantageous. The reduced material thickness, preferably approximately 0.4 millimeters, is preferably achieved during the roll forming process preceding the welding process, for example, by applying rolling pressure to one side. The sections to be welded together, for example, along a longitudinal line of the hollow profile, preferably have a material thickness reduced by 40 to 60 percent compared to the material thickness of the remaining areas of the formed flat or strip material, e.g., 0.8 millimeters or more. When opposite edges of the formed flat or strip material are to be welded together, both edges have a reduced material thickness, preferably the same reduced material thickness of approximately 0.4 millimeters. The width at the end of the material edge to be welded, over which the material thickness is reduced, is in the millimeter range. If the guide rail according to the invention is made from a plastic material, an extrusion process for its manufacture is advantageous. The invention also includes a piece of furniture or household appliance, in particular a kitchen appliance, comprising a body and a drawer element, wherein the drawer element is movably mounted on the body by means of a guide system, and wherein a guide system according to the invention is provided for the drawer element according to one of the embodiments discussed above. This allows the advantages described above to be achieved in the furniture or household appliance. Character description Further features and advantages of the invention are explained in more detail with reference to the exemplary embodiments of the invention shown in the figures. Specifically: Fig. 1 shows a schematic representation of a piece of furniture according to the invention in a perspective view from above, with a drawer slidably mounted thereon; Fig. 2 shows a cross-sectional perspective view of a piece of furniture according to the invention in the area of ​​a drawer side, adjacent to a furniture carcass wall and a furniture carcass base; Fig. 3 shows the section according to Fig. 2 in an end view; Fig. 4 shows an exploded view of a component of a guide system according to the invention; Fig. 5 shows a perspective view of an end section of a central rail of the guide system according to Fig. 4; Fig. 6 shows an end view of the central rail according to Fig. 5; and Fig. 7 shows the outlined area A in Fig. 6 in an enlarged detail view without a stop 35. For corresponding elements of different embodiments, the same reference symbols are sometimes used below. Fig. 1 shows a highly schematic representation of a piece of furniture 1 according to the invention in a functional state, comprising a hollow, cuboid furniture body 2 and a drawer element designed as a drawer 3, wherein the drawer 3 is slidably mounted on the furniture body 2. The furniture body 2 includes two opposing vertical side walls 4 and 5, between which the drawer 3 can be pulled out of the furniture body 2 in a horizontal direction according to P1 and pushed in in the opposite direction according to P2 via a guide system according to the invention with telescopic guide elements or a first full-extension rail 6 and a second full-extension rail 7. In Fig. 1, the drawer 3 is shown in the state of being maximally or completely extended from the interior of the furniture body 2. This allows almost unimpeded access to the storage volume of the drawer 3 from above. If drawer 3 uses partial extension slides instead of full extension slides 6 and 7, it cannot be moved as far out of the interior of the furniture carcass 2 towards P1 when fully extended, as is possible with full extension slides 6 and 7 as shown in Fig. 1. The front element 12 is then closer to the open front of the furniture carcass 2 than shown for drawer 3 in Fig. 1. The full extension rail 6, screwed to the inside of the side wall 4, is located opposite at the same vertical height as the full extension rail 7, which is screwed to the side wall 5 and hidden in Fig. 1, and which is indicated by dashed lines. In the furniture body 2, above the drawer 3, a further drawer can be accommodated, guided accordingly by rail full extensions 8 and 9, which is not shown in Fig. 1. Drawer 3 has opposing drawer side walls 10, 11, each comprising a constructed hollow chamber frame. Drawer 3 also includes a front element 12, a back wall 13 horizontally opposite it, and a horizontally extending drawer base 14, which extends to or is connected with the drawer side walls 10, 11, the front element 12, and the back wall 13. Figures 2 and 3 show a section of a drawer 3 in the area of ​​a cabinet side panel 5, comprising a drawer bottom 14, a drawer side panel 11 designed as a hollow chamber frame 15, and a back panel 13. The drawer 3 is mounted on the cabinet body 2 via two components of a guide system according to the invention, or via a full-extension slide 16 according to the invention on the side panel 5, and in the same way via a further hollow chamber frame of the drawer 3 on the side panel 4 (not shown in Figure 2). On the side panel 4, the drawer 3 is mounted via a further component or a further full-extension slide according to the invention, allowing it to be linearly displaceable horizontally in directions P1 and P2. The hollow chamber frame 15, preferably made of bent sheet metal, has an outer housing 15a and an inner structure 15b, such that the full extension 16 can be recessed within the inner volume of the hollow chamber frame 15. On an inner surface of the hollow chamber frame 15 in its lower section, this surface is designed to receive a longitudinal edge of the drawer base 14. The full extension 16 according to the invention, formed as a component of the guide system, comprises three mutually telescopic guide rails or a body rail 17, a middle rail 18 and a sliding element rail 19. The middle rail 18 is designed as a hollow profile according to the invention. A movable drawer element, such as the drawer 3, is coupled or connected to the drawer element rail 19, for example, fixed to the hollow chamber frame 15, whereas the cabinet rail is connected to the fixed part of the furniture. If the full extension 16 is used as an under-mount guide, the underside of a drawer element, or its bottom, rests on a top surface 19a of the drawer element rail 19. A hook element 19b projecting upwards from the rear end of the drawer element rail 19 forms a stop for a section of the rear outer surface of the drawer element. For precise positioning, a section of the hook element 19b angled parallel to the top surface 19a engages in a correspondingly prepared recess in the rear outer surface of the drawer element. Thus, in Fig. 4, the rear portion of the full extension 16, shown on the left side, is also defined in the operating state.a front area of ​​the full extension 16 in the usable state is defined, in Fig. 4 on the right side. Furthermore, the full extension 16 includes a first or lower carriage 20 with bearing bodies arranged on it, wherein the carriage 20 acts between the body rail 17 and the middle rail 18 for a load-transmitting relative movement of the rails 17, 18. Furthermore, the full extension 16 comprises a second or upper carriage 21 with bearing bodies arranged on it, wherein the carriage 21 acts between the middle rail 18 and the push element rail 19 for a load-transmitting relative movement of the rails 18, 19. Pins 32 are provided on a vertically oriented, inwardly pointing narrow side of a rail body 31 of the cabinet rail 17, via which a movement mechanism 22 of the full extension 16, for example for pushing out and / or pulling in the drawer 3, can be attached. The cabinet rail 17 includes two L-shaped fastening elements 33 and 34, the fastening elements 33 and 34 serving to fasten or fix the full extension to an inside of the side wall of a cabinet, such as the side wall 5 of the cabinet 2 of the furniture 1. The guide rails 17, 18, 19 preferably consist of a sheet metal material which, starting from the flat sheet metal material, is formed into the final product of the respective guide rail, for example by a punching and bending process. Fig. 5 shows the front end section of the center rail 18 in relation to the usable state of the full extension 16. According to the illustrated embodiment, the center rail 18 has an upper flat horizontal wall section 23, a lower flat horizontal wall section 24, two flat upper side wall sections 25, 26, two lower flat side wall sections 27, 28 and intermediate sections 29 and 30. Horizontal wall section 23 forms a distal wall or upper surface of the central rail 18 or the corresponding hollow profile. Similarly, horizontal wall section 24 forms a distal wall or lower surface of the central rail 18 or the hollow profile. The terms "top" and "bottom" refer to the orientation of the full extension 16 in its usable state and in its state attached to the furniture, as shown particularly in Figures 2 and 3. The planes spanned by the mutually parallel horizontal wall sections 23 and 24, or by their outer and distal sides respectively, are at least nearly horizontally aligned. The center rail 18 or the center rail hollow profile is advantageously designed to be mirror-symmetrical with respect to the planes E1 and E2 which are perpendicular to each other (see Fig. 6). In Fig. 6, two directions, D1 upwards and D2 downwards, are shown parallel to plane E2. These directions, along a vertical axis of the central rail 18, indicate a distal direction, or a direction away from the center along the longitudinal axis L, in its operating state. Distal directions also exist along plane E1, running along a lateral axis of the central rail 18. To limit the relative movement of the lower carriage 20 and the upper carriage 21 along the longitudinal axis of the central rail 18 in relation to a central longitudinal axis L (see Fig. 5), upper stops 35 and lower stops 36 are provided on the central rail 18. In the assembled full extension 16, the bearing bodies mounted on the carriages 20, 21 run on the outwardly facing sides of the center rail 18 or the horizontal wall sections 23, 24 and the side wall sections 25-28. The lower carriage 20, with its sections 20a and 20b carrying the bearing bodies, encompasses the horizontal wall section 24 and the side wall sections 27, 28 on the outside. The upper carriage 21, with its sections 21a and 21b which support the bearing bodies, surrounds the horizontal wall section 23 and the side wall sections 25, 26. Accordingly, the respective associated bearing bodies of the lower carriage 20 roll on the distal side or the outer side 24a of the lower horizontal wall section 24, on the outer side 27a of the side wall section 27 and on the outer side 28a of the side wall section 28. The respective associated bearing bodies of the upper carriage 21 roll on the distal side or outer side 23a of the upper horizontal wall section 23, on the outer side 25a of the side wall section 25 and on the outer side 26a of the side wall section 26. The bearing bodies of the carriages 20, 21 are preferably externally cylindrical bearing bodies or rolling bearing bodies such as bearing rollers or bearing needles. The central rail 18, originally formed from a flat sheet metal, is designed as a hollow profile and has a material-bonded connection, a welded joint, or a narrow weld seam 37 along its length along the longitudinal axis L. The weld seam 37, preferably produced by a continuous laser process, joins narrow, butt-jointed sides of a lower section 30a and an upper section 30b of the intermediate section 30. For an advantageously produced material-bonded connection of the partial areas 30a and 30b, their mutually facing edges 38, or the edges 38 of the butt-jointed sides, are reduced in material thickness compared to the material thickness s (see Fig. 7) of the remaining material of the central rail 18 and are, for example, in the range of half the material thickness (see Fig. 6) compared to the sheet thickness s, which the remaining material areas have uniformly. A similar connecting section 39 is formed between a first longitudinal edge of the upper horizontal wall section 23 and the side wall section 25 and between a second longitudinal edge of the upper horizontal wall section 23 and the side wall section 26. In a similar manner, a similar connecting section 40 is formed between a first longitudinal edge of the lower horizontal wall section 24 and the side wall section 27 and between a second longitudinal edge of the lower horizontal wall section 24 and the side wall section 28. Preferably, or in particular for a mirror symmetry about two perpendicular planes E1, E2, all four connecting sections 39 and 40 are identically designed. In Fig. 7, stop 35 has been omitted for better illustration. The connecting sections 39 and 40 are formed by a forming or bending process and extend over the entire length of the central rail 18. The connecting sections 39 and 40 have a loop-shaped cross-section as shown in Figures 6 and 7. The connecting sections 39 project slightly beyond the distal side or the upper surface of the central rail 18 formed by the horizontal wall section 23. The connecting sections 40 also project slightly downwards beyond the distal side or the underside of the central rail 18 formed by the horizontal wall section 24. The connecting sections 39, 40 advantageously connect mutually perpendicular flat sections of the central rail 18, i.e., a horizontal wall section 23, 24 and an adjoining side wall section 25-27, made from a continuous, originally flat sheet metal section, and provide a mechanically highly stable hollow profile. In particular, the central rail 18 exhibits a comparatively high bending stiffness against bending along the longitudinal axis L and increased stability against twisting or torsion about the longitudinal axis L. Overall, this contributes to the stiffening of the central rail 18 compared to a connection of a horizontal wall section with a side wall section via a simple bend between the horizontal wall section and the side wall section. Furthermore, the shaping and stabilization are made possible in a compact, space-saving, and material-saving manner. The preferably similar connecting sections 39, 40 are explained below with reference to the specific connecting section 39 shown in Fig. 7. As can be seen particularly clearly in detail from the front view according to Fig. 7, a planar bending section 42 connects to the upper horizontal wall section 23, or laterally along the outer side over the length of the horizontal wall section 23, via a first bend 41 at a point B1. A further bend 43, opposite to bend 41, connects to bend 42 by an angle of 180 degrees and transitions into a support section 44. The support section 44 is adjacent to and parallel to bend 42. The support section 44 extends without further bending into the upper side wall section 26, or rather, the support section 44 represents an extension of the side wall section 26. The planar side wall section 26 extends diagonally downwards over the section width a1 to a further bend 45, which transitions into the intermediate section 30 with the vertical wall section. Advantageously, an inner side of the bending section 42 is in contact with an inner side of the support section 44 over its substantial extent. For the upper bearing bodies of the upper carriage 21, which roll on the outside 23a of the horizontal wall section 23 during a displacement movement of the rails 18 and 19, the upwardly bent bending section 42 can act as a lateral limit over the length of the middle rail 18 between the front stops 35 and the rear stops 35. On the other longitudinal side of the horizontal wall section 23, the corresponding bending section of the other connecting section 39 acts in a similar manner as a further lateral boundary of the upper bearing bodies of the carriage 21. In the vertical direction, the hollow profile with the connecting section 39 exhibits an increase a2 from the top surface 23a of the horizontal wall section 23 to a highest point H1 in the area outside the bend 43. The values ​​a2 and a3 can also be lower or even zero. In the width direction or perpendicular to the height direction, the hollow profile with the connecting section 39 widens a3 from point B1 on the longitudinal edge of the horizontally oriented top surface 23a of the horizontal wall section 23 to a maximally far outer point B2 in the area outside the bend 43. An internal angle α between the plane according to the inside of the horizontal wall section 23 and the plane according to the inside of the side wall section 26 is preferably between 20 and 70 degrees, preferably between 35 and 55 degrees, preferably approximately 45 degrees, which is realized in the case of the center rail 18. In principle, with the same design of the connecting section 39, the side wall section 26 according to Fig. 7 can form a horizontal wall section of an alternative center rail according to the invention, and the horizontal wall section 23 according to Fig. 7 can form a side wall section of the alternative center rail. In other words, the cutout shown in Fig. 7 can be rotated counterclockwise until the side wall section 26 is horizontally aligned and forms the horizontal wall section of the alternative center rail. The connecting section 39 then represents the transition from the alternative horizontal wall section to the alternative side wall section. Thus, there is no overhang on the upper side of the alternative horizontal wall section. This also means that the lateral limiting function for the bearing bodies of the upper carriage 21, which roll on the outside of the horizontal wall section, is missing. However, the bending section 42 then forms a lateral upper boundary for the bearing bodies of the upper carriage 21, which roll on the outside of the alternative side wall section. Other deviations from the full extension 16 shown in Figs. 2, 3, 4, 5, 6 to 7, in particular regarding the design of the center rail and especially the connecting sections 39 and 40, are also within the scope of the present invention and lead to alternative advantageous center rails according to the invention. For example, according to an alternative advantageous embodiment of the invention, the contact between the inside of the bending section 42 and the inside of the support section 44 can be completely or partially eliminated, resulting in a preferably small distance or air gap in the millimeter range between the inside of the bending section 42 and the inside of the support section 44. Reference symbol list: 1 Furniture 2 Furniture carcass 3 Drawer 4 Side panel 5 Side panel 6 Full extension runner 7 Full extension runner 8 Full extension runner 9 Full extension runner 10 Drawer side panel 11 Drawer side panel 12 Front element 13 Back panel 14 Drawer bottom 15 Hollow chamber frame 15a Housing 15b Internal structure 16 Full extension 17 Carcass runner 18 Center runner 19 Drawer element runner 19a Top 19b Hook element 20 Runner 20a Section 20b Section 21 Runner 21a Section 21b Section 22 Movement mechanism 23 Horizontal wall section 23a Outer side 24 Horizontal wall section 24a Outer side 25 Side panel section 25a Outer side 26 Side panel section 26a Outer side 27 Side panel section 27a Outer side 28 Side panel section 28a Outer side 29 Intermediate section 30 Intermediate section 30a Subsection 30b Subsection 31 Rail body 32 Pin 33 Fastening element 34 Fastening element 35 Stop 36 Stop 37 Weld 38 Edge 39 Connecting section 40 Connecting section 41 Bend 42Bend section 43 Bend 44 Support section 45 Bend

Claims

Guide rail of a guide system (16) for a sliding element (3), in particular for a sliding element (3) of a piece of furniture (1) or a household appliance such as a kitchen appliance, wherein the guide rail is designed as a hollow profile enclosed by wall sections of the guide rail, wherein the wall sections comprise a horizontal wall section (23, 24) and two side wall sections (25, 26; 27, 28), wherein the horizontal wall section (23, 24) extends parallel and perpendicular to a longitudinal extension of the guide rail, wherein the side wall section (25, 26; 27, 28) extends parallel and perpendicular to the longitudinal extension of the guide rail, wherein the side wall sections (25, 26; 27, 28) are oriented at an angle to the horizontal wall section (23, 24), wherein the horizontal wall section (23, 24) and the two side wall sections (25, 26;27, 28) in a cross-section perpendicular to a longitudinal extension of the guide rail, at least section by section, form the three sides of a triangle, wherein the horizontal wall section (23, 24) defines a distal wall of the hollow profile, characterized in that the horizontal wall section (23, 24) forms a top and / or a bottom of the hollow profile.; Guide rail of a guide system (16) for a push element (3) according to claim 1, characterized in that the wall sections comprise a connecting section (39, 40), wherein the horizontal wall section (23, 24) and the side wall section (25, 26; 27, 28) are connected via the connecting section (39, 40), wherein the connecting section (39, 40) has a support section (44) and a bending section (42) located at the support section (44) at an angle, in particular bent, and wherein the bending section (42) is angled towards the support section (44) to such an extent that the bending section (42) and the support section (44) enclose a bending angle in a range between 45 degrees and 180 degrees. Guide rail according to claim 2, characterized in that the connecting section (39, 40) is designed such that one side of the bending section (42) comes into contact with the support section (44). Guide rail according to one of the preceding claims, characterized in that the guide rail is formed from a formed flat material. Guide rail according to one of the preceding claims, characterized in that the hollow profile is mirror-symmetrical in a cross-section in two mirror planes, wherein the two mirror planes are perpendicular to each other. Guide rail according to one of the preceding claims, characterized in that the wall sections have a vertical wall section (29, 30) wherein the vertical wall section (29, 30) connects side wall sections (26, 28; 25, 27) to each other. Guide rail according to one of claims 2 and 3, characterized in that the support section (44) is aligned parallel to a side wall section (25, 26; 27, 28). Guide rail according to one of claims 2, 3 and 7, characterized in that the bending section (42) is aligned parallel to a side wall section (25, 26; 27, 28), in particular parallel to a support section (44). Guide rail according to one of claims 2, 3, 7 and 8, characterized in that the hollow profile in the area of ​​the connecting section (39, 40) has a stop element (35, 36) acting in the longitudinal direction of the hollow profile. Guide rail according to one of the preceding claims, characterized in that the horizontal wall section (23, 24) and / or the side wall section (25, 26; 27, 28) each form a contact surface for parts of a bearing arrangement at least over a partial length of the guide rail. Guide system for a drawer element (3), in particular a linear guide system for a drawer element (3) of a piece of furniture (1) or a household appliance such as a kitchen appliance, wherein the guide system comprises a unit with exactly two guide rails, wherein the guide rails comprise a cabinet rail and a drawer element rail slidably mounted on the cabinet rail, wherein the drawer element rail is designed for connection with the drawer element, wherein a carriage is provided between sections of the cabinet rail and the drawer element rail for relative movement of the cabinet rail and the drawer element rail, characterized in that the cabinet rail is designed as a guide rail according to one of the preceding claims. Guide system (16) for a sliding element (3), in particular a linear guide system for a sliding element (3) of a piece of furniture (1) or a household appliance such as a kitchen appliance, wherein the guide system (16) comprises a unit with exactly three guide rails, wherein the guide rails comprise a cabinet rail (17), a sliding element rail (19) and a center rail (18), wherein the sliding element rail (19) is configured for connection with the sliding element (3), wherein the center rail (18) is provided between the cabinet rail (17) and the sliding element rail (19), wherein a carriage (20) is provided between sections of the cabinet rail (17) and the center rail (18) and a carriage (21) is provided between sections of the center rail (18) and the sliding element rail (19) for relative movement between the rails (17, 18, 19), characterized in that the center rail (18) is configured as a guide rail according to one of claims 1 to 10. Method for manufacturing a guide rail according to one of claims 1 to 10, wherein the guide rail is manufactured from a flat material, in particular from a strip material, wherein the manufacture of the guide rail is carried out by a continuous forming process of the flat or strip material. Method for manufacturing a guide rail according to claim 13, characterized in that the continuous forming process of the flat or strip material is carried out by a continuous roll forming process. Method according to one of claims 13 and 14, characterized in that in a subsequent step to the continuous forming process of the flat or strip material, a welded joint (37) between sections (30a, 30b) of the formed flat or strip material is made by a continuous laser welding process. Method according to one of claims 13 to 15, characterized in that the welding between the sections of the formed flat material is carried out in such a way that the material thickness in the area of ​​the material to be welded is reduced compared to the remaining areas of the formed flat or strip material. Furniture (1) or household appliance, in particular kitchen appliance, comprising a body (2) and a drawer element (3), wherein the drawer element (3) is movably received on the body (2) by means of a guide system (6, 7), characterized in that a guide system for the drawer element according to one of claims 11 to 12 is provided.

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