Multi-component ceramic support element

Abstract

The present invention relates to a multi-part ceramic support element (1) for spacing ceramic shelves (80) of an oven rack (100), comprising an upper part (2) and a lower part (3), the upper part (2) being detachably connectable to the lower part (3) in an axial direction by means of a locking connection to secure the shelves (80) between the upper part (2) and the lower part (3), the locking connection being formed by a tenon (7) on one part (2) having one or more locking projections (11) protruding from the tenon (7) and respective openings (12) on the other part (3), such that the tenon (7) can be inserted into the openings (12) and simultaneously rotated within the openings (12) without moving in or out of the openings (12), so that the locking projections (11) can each lock into a locking receptacle (31) formed by the part (3) having the openings (12).

Description

[Technical Field]

[0001] The present invention relates to a multi-piece ceramic support element for spacing ceramic shelves in an oven rack (furnace rack). [Background technology]

[0002] Multi-component ceramic support elements for spacing ceramic shelves are known in the prior art. For example, WO 2007 / 132276 (A1) discloses a ceramic support element having an upper and lower part, with a tenon with an external thread disposed on the upper side of the lower part, which is screwed into an internal thread provided in an opening on the lower side of the upper part. A disc stand or fire protection plate is tightly screwed between the upper and lower parts as a shelf. DE 10 2008 022 159 B4 discloses a further multi-component ceramic support element that can detachably connect the upper and lower parts axially by a threaded connection to secure the shelf between the upper and lower parts. DE 10 2004 023 076 A1 discloses a device for connecting coaxial pipes, particularly for a shelf system. Further prior art can be found in DE 10 2018 114 817 A1 and DE 10 2014 115 098 A1.

[0003] In general, a drawback of threaded ceramic support elements is that a secure press-fit connection cannot be achieved by applying a preload due to the material properties of the high-temperature-resistant ceramic material used for the support elements and shelves. In any case, the threaded connection must not be fully tightened, as this could damage the ceramic material, which would lead to the threaded connection loosening. As practice has shown, threaded connections can also loosen due to vibrations and, as a rule, due to movements during robot-assisted automated handling of the shelves to which the support elements are attached. Additionally, thermal stresses during use in an oven can also lead to loosening of the threaded connection.

[0004] This creates a major problem for automated handling and loading / unloading of oven racks. Since loose screw connections always involve local changes in the distance and position of shelves within the oven rack, the normally precisely defined gripping and placement positions of the gripping arms in the automated manufacturing process no longer fit, which may even result in damage to the oven rack. This means that defects may occur in the automated manufacturing process, and correcting them is disadvantageous in terms of time and cost. Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above, the object of the present invention is to provide a multi-component ceramic support element for spacing the shelves of ceramic oven racks, which overcomes the above-mentioned drawbacks of the support elements known in the prior art, ensures trouble-free operation even in automated manufacturing processes, and is characterized by a simple design and a long service life even at the highest oven temperatures. [Means for solving the problem]

[0006] The object of the invention is achieved by a multi-component ceramic support element according to independent claim 1. Preferred embodiments are evident from the dependent claims. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of an embodiment of an oven rack according to the present invention. [Figure 2] 2 is a perspective view of an embodiment of the upper and lower parts of the support element of the oven rack of FIG. 1 before assembly. [Figure 3] Figure 3A is a perspective view of the oven rack element of the oven rack of Figure 1 before assembly of the upper and lower pieces of Figure 2. Figure 3B is a perspective view of the oven rack element of Figure 3A after assembly of the upper and lower pieces. [Figure 4]Figure 4A is a perspective view of the upper and partially cut-away lower parts of Figure 2 before fastening, Figure 4B is a similar view to Figure 4A of the upper and lower parts after fastening without a securing pin, and Figure 4C is a similar view to Figure 4A of the upper and lower parts after fastening with a securing pin. [Figure 5] 5 is a cross-sectional view through two adjacent shelves of the oven rack of FIG. 1. FIG.

[0008] The present invention provides a multi-component ceramic support element for spacing ceramic shelves of an oven rack. The multi-component ceramic support element is composed of one or more ceramic materials, i.e., does not contain non-ceramic materials. The multi-component ceramic support element includes an upper part and a lower part for securing a shelf between the upper and lower parts. The upper and lower parts are preferably manufactured using a casting process, particularly an injection molding process. DETAILED DESCRIPTION OF THE INVENTION

[0009] The terms "upper component" and "lower component" refer to the relative arrangement of the two components in a typically horizontal working position of a fixed shelf in an oven rack, with the upper component being positioned at least partially above the fixed shelf and the lower component being positioned at least partially below the fixed shelf.

[0010] In the support element according to the invention, the upper and lower parts are axially detachably connectable by a locking connection formed by a tenon in one part (e.g., the upper part) with one or more locking projections protruding from the tenon and an opening in the other part (e.g., the lower part), such that the tenon can be inserted into the opening and rotated in the opening without simultaneously moving into or against the opening, so that the one or more locking projections can each be latched into a locking receptacle formed by the part with the opening. Movement of the tenon out of the opening is prevented by the locking connection.

[0011] A "tenon" within the meaning of the present invention is understood to mean an element protruding from one part and which, due to its geometric shape, is suitable to be inserted into an opening provided in another part to establish a detachable locking connection. Typically, tenons are designed elongated.

[0012] An "opening" in the sense of the present invention is understood to mean a cavity formed by the other part and having a shape such that the tenon can be at least partially inserted into said cavity.

[0013] According to an advantageous embodiment, the part with the opening is designed in the form of a sleeve, which, according to the common understanding of the term "sleeve", is understood to mean a hollow body with a cylindrical outer shape.

[0014] For purposes of the present invention, "axial" or "axial" is understood to mean the direction in which the tenon can move into the opening or the opposite direction in which the tenon can move out of the opening. Thus, "axial" corresponds to the direction of assembly or disassembly of the multi-part support element. The term "radial" refers to a direction perpendicular to the axial direction.

[0015] According to the present invention, the upper and lower parts of the multi-part support element can be axially detachably connected by a latching connection. Because of this axial connection between the upper and lower parts by latching, the upper and lower parts cannot be axially loosened in the latched state, i.e., the tenon cannot be moved out of the opening. For this purpose, the tenon has one or more locking protrusions, which can be locked into the locking recesses by rotating the tenon in the opening. This requires that the tenon can be at least partially inserted into the opening, i.e., the opening must have a shape such that the tenon with one or more locking protrusions can be at least partially inserted into the opening and the one or more locking protrusions are located within the opening. Preferably, the opening has a shape that partially corresponds to the tenon and the one or more locking protrusions.

[0016] In a practical embodiment, the opening is partially shaped so that the tenon inserted therein can rotate therein, thereby allowing one or more locking projections to be fastened in the locking receptacles formed by the parts having the opening. According to the invention, the tenon can rotate about an axially arranged rotation axis, preferably in both directions of rotation. According to the invention, the tenon can rotate in the opening without simultaneously moving axially, i.e., without forcible movement of the tenon into or out of the opening when the tenon is rotated. Therefore, the locking connection according to the invention is fundamentally different from rotary connections designed as bayonet or screw connections. Therefore, no (forcible) guide for the locking projection(s) is provided when rotating the tenon in the opening. It is advantageous to be able to rotate the tenon in the opening so that the locking projection(s) move only in a plane perpendicular to the axial direction.

[0017] According to an advantageous embodiment, the opening, starting from the side where the tenon is inserted into the opening, is designed to have a (radial) cross-sectional surface in a first region that corresponds to the (radial) cross-sectional surface of the tenon with one or more locking projections. Therefore, the opening is not hollow-cylindrical, but is designed to have different diameters at the same axial height, at least one of which is smaller than the combined diameter of the tenon and the one or more locking projections at the axial height of the tenon where the one or more locking projections are located, so that the tenon cannot rotate in the opening when the one or more locking projections are located in the first region. The first region is adjacent to a second region of the opening with a hollow-cylindrical cross-sectional surface, which has a (single) diameter that corresponds at least to the combined diameter of the tenon and the one or more locking projections at the axial height of the tenon where the one or more locking projections are located, so that the tenon can rotate in the opening when the one or more locking projections are located in the second region. In this embodiment, it is particularly advantageous if the locking receiver is limited in the axial direction by a shoulder that projects radially inwards.

[0018] The support element according to the invention therefore advantageously allows for a detachable locking connection between the upper and lower parts for fixing the shelves, which ensures a reliable and secure connection between the upper and lower parts without the risk of the distance between them being changed, as is typically the case with screw or bayonet connections, thereby preventing interruptions in the automated production process due to random height or shelf position changes.

[0019] The upper and lower parts of the support element according to the invention can be axially connected in an automated manner, for example by means of a gripping arm, in which case only the tenon has to be rotated in the opening, for example by a predetermined rotation angle, which is a further important advantage of the invention.

[0020] According to an advantageous embodiment, the tenon has a plurality of locking projections, which can be latched into separate locking recesses. In this respect, a separate locking recess can be provided for each locking projection. However, it is also possible to provide a common locking recess for more than one locking projection.

[0021] According to a further advantageous embodiment, the ceramic support element has at least two locking receivers, which are arranged so that the locking projection can be latched into one of the two locking receivers by rotating the tenon in one or another rotational direction, particularly by an equal rotational angle, for example, by 90°. This embodiment has the particular advantage that there is no need to specify a rotational direction, which can cause problems depending on the orientation of the part providing the opening. Rather, latching can be achieved in any case, even if the rotational direction in which the tenon must be rotated to achieve latching is not precisely defined.

[0022] According to a further advantageous embodiment, the part with the opening designed in the form of a sleeve has an end surface that serves to abut against the shelf. This allows for particularly easy fastening of the shelf. In this case, in particular, the part with the tenon has a disk-shaped area (disk-shaped area) with a lower side facing the opening and an upper side facing away from the opening, and the tenon protrudes from the lower side of the disk-shaped area. Particularly advantageously, the lower disk surface of the disk-shaped area is substantially flat and is provided to abut against the shelf. This also allows for particularly easy fastening of the shelf.

[0023] In principle, it is arbitrary which parts of the support element form the tenon and the opening. Advantageously, the part with the tenon is the upper part, and the part with the opening is the lower part. The distance between the shelves can be easily adjusted, especially due to the lower part being designed in the form of a sleeve and allowing for easy change of the axial dimension.

[0024] According to a further advantageous embodiment, the locking projection or projections are fastened to the locking receiver with axial and / or radial play, respectively. According to the invention, axial or radial play is understood to mean that the locking projection can move freely in the locking receiver over a certain length in the axial or radial direction.

[0025] According to a further advantageous embodiment, the multi-component ceramic support element has a rotation lock for fixing the rotational position of the tenon in which one or more locking projections are engaged. As a result, undesired rotation of the tenon that would release the locking connection is prevented. Advantageously, the rotation lock is formed by one or more plug pins, each of which is received in a pin receiver that is at least partially formed together by the upper and lower parts and shaped to fit the plug pin. Thus, the pin receiver is at least partially formed by the upper part and partially by the lower part. In other words, a portion of the pin receiver in the direction of its extension is formed by the upper part, and a further portion is formed by the lower part. In this way, the plug pin is partially surrounded by the upper part and partially surrounded by the lower part in its pin receiver, so that the relative rotational position of the upper and lower parts can be fixed or blocked. Advantageously, the pin receiver extends axially. The plug pin and the corresponding pin receiver can have any desired (radial) cross-sectional shape. If the upper and lower parts are manufactured using a casting process, the cross-sectional shape of the pin receiver can be designed as desired. For example, the plug pin has a circular, rectangular or triangular shape in its radial cross section. The pin receiver has a corresponding cross section, for example, a circular, rectangular or triangular.

[0026] It is particularly advantageous if one or more plug pins each abut against a locking projection, in this way each plug pin can be easily inserted into and removed from the pin receiving part without the need to fix the pin to the pin receiving part.

[0027] Basically, the design of the locking projections and locking receivers is arbitrary, as long as it ensures that the upper and lower parts are firmly connected in the axial direction in the fastened state. Advantageously, the one or more locking projections are each designed in the form of a flange projecting radially outward, and the one or more locking receivers are each designed in the form of a shoulder projecting radially inward, which allows for a particularly simple design.

[0028] The present invention further relates to an oven rack element having a shelf with at least one hole and at least one multi-component support element according to the present invention, the shelf being secured between an upper part and a lower part by the support element extending through the hole, advantageously with the support element being arranged in each corner region of the shelf, for example in the corner region of a rectangular shelf.

[0029] The present invention further relates to an oven rack having a lower shelf and at least one upper shelf, wherein the lower shelf is secured between an upper part and a lower part of at least one support element according to the present invention, and the at least one upper shelf is secured between an upper part and a lower part of at least one support element according to the present invention, with the lower part of the at least one support element securing the upper shelf abutting adjacently only the upper part of the support element securing the lower shelf. In this way, forces are advantageously transmitted only between the support elements. The shelves themselves are not subjected to any load, which is a major advantage.

[0030] Preferably, all shelves, i.e., the lower shelf and one or more upper shelves arranged one above the other, are supported by at least one, preferably three or four, multi-component support elements according to the invention. In each case, the shelves may be plate-shaped or designed as disc stands.

[0031] The support elements and shelves, along with the oven rack elements and oven rack, are made of one or more ceramic materials, such as, for example, silicon carbide or mullite, but do not include any non-ceramic materials.

[0032] The invention will now be explained in more detail with reference to the drawings, which are schematic representations and are not to scale, and which in no way limit the invention.

[0033] FIG. 1 is a perspective view of an embodiment of an oven rack according to the present invention; FIG. 2 is a perspective view of an embodiment of upper and lower parts of a support element of the oven rack of FIG. 1 before assembly; FIG. 3A is a perspective view of the oven rack element of the oven rack of FIG. 1 before assembly of the upper and lower parts of FIG. 2; FIG. 3B is a perspective view of the oven rack element of FIG. 3A after assembly of the upper and lower parts; FIG. 4A is a perspective view of the upper and lower parts of FIG. 2 before fastening; FIG. 4B is a view similar to FIG. 4A of the upper and lower parts after fastening without fastening pins; FIG. 4C is a view similar to FIG. 4A of the upper and lower parts after fastening with fastening pins; and FIG. 5 is a cross-sectional view through two adjacent shelves of the oven rack of FIG. 1.

[0034] FIG. 1 shows a perspective view of an embodiment of an oven rack according to the present invention, generally designated 100. The oven rack 100 comprises a plurality of plate-shaped oven rack elements 90 stacked vertically one above the other. Each oven rack element 90 comprises a rectangular shelf 80 made of a ceramic material, which is designed in the form of a flat plate and has a support element 1 made of a ceramic material at each of its four corner regions. Each of the four support elements 1 secures a shelf 80. When the oven rack elements 90 are stacked, the support elements 1 function as support spacers for spacing one shelf 80 from its immediately adjacent shelf 80. In particular, the support elements 1 ensure the correct distance between two immediately adjacent shelves 80 and the correct position or alignment of each shelf 80 relative to its immediately adjacent shelves 80. Preferably, the stacked shelves 80 are arranged parallel to one another, typically horizontally in the working position. In the case of flat shelves 80, this is achieved by the equal dimensions of the axially extending portions of the parts of the support elements 1 located between the shelves 80.

[0035] The shelves 80 of the oven rack 100 are used to load the baking material for storage and transport of the baking material through the oven. The oven rack 100, loaded with baking material at various levels, can be transported in and out of the oven, which is known to those skilled in the art and need not be described in further detail here.

[0036] In the oven rack 100, the oven rack elements 90 are stacked on top of one another by gravity alone, without being fixed to one another. In Figure 1, the stacking of one shelf 80 on top of another shelf 80 is indicated diagrammatically by arrows. The assembly / disassembly of the oven rack 100 by stacking / disassembling the oven rack elements 90, as well as the loading / unloading of the shelves 80 with baking material, is advantageously carried out in an automated manner (robotically assisted) by a gripping arm. It will be understood that precise positioning of the shelves 80 in the oven rack 100 is necessary for the usually precisely defined gripping positions of the gripping arm.

[0037] Figure 2 is a perspective view of an embodiment of the upper part 2 and the lower part 3 of a support element 1 according to the invention before assembly on a shelf 80. In Figure 2, the arrows indicate the assembly direction (axial direction) of the upper part 2 and the lower part 3, perpendicular to which a radial direction is defined. Both the upper part 2 and the lower part 3 are manufactured using a casting method, in particular an injection molding method.

[0038] The upper part 2 comprises a centrally located tenon 7 and a disk-shaped flange portion 4 having an upper disk portion 5 and a lower disk portion 6. The tenon 7 protrudes from the lower disk portion 6. The lower disk portion 6 has a lower disk surface 9 that surrounds the tenon 7. The upper disk portion 5 has a centrally located centering collar 8. The upper disk portion 5 has an upper disk surface 10 that surrounds the centering collar 8. In the embodiment shown in Figure 2, the lower disk surface 9 and the upper disk surface 10 of the disk-shaped flange portion 4 are each flat.

[0039] The tenon 7, which has a substantially cylindrical outer shape, has two locking projections 11 directly adjacent to its free end. The locking projections 11 are each designed as radially (outwardly) protruding flanges and, in the exemplary embodiment, are arranged opposite each other at the same axial height on the tenon 7. The diameter (radial dimension) of the two locking projections 11 increases relative to the diameter of the tenon 7. The two locking projections 11 do not extend over the entire circumference of the tenon 7, but are formed only in specific regions, so that a region of reduced diameter of the tenon 7 remains between the locking projections 11. Correspondingly, the two locking projections 11 do not extend along the entire axial length of the tenon 7, but are formed only in specific regions, so that a reduced diameter of the tenon 7 also exists towards the disk-shaped flange 4. The tenon 7 does not have a thread.

[0040] The lower part 3 shown in Figure 2 is designed as a hollow body with a continuous opening 12 defined by a side surface 19. For example, here the lower part 3 is designed in the form of a sleeve and has an upper part 13 with an upper surface 16 and a lower part 14 with a lower surface 15. The two lower part surfaces 15, 16 are formed by the terminal end faces of the sleeve and are each flat.

[0041] As can be seen in FIG. 2 , the continuous opening 12 has a cross-sectional surface in an upper region 17 directly adjacent to the upper part 13 of the lower part, which matches the cross-sectional surface of the upper part 2 in the region of the tenon 7 and the two locking projections 11, so that the tenon 7 with the locking projections 11 can be inserted into the opening 12. The cross-sectional surface is a surface in a radial plane. Therefore, in the upper region 17, the cross-sectional surface is not circular, and the side surface 19 has two opposing bulges 20 for the locking projections 11. Adjacent to the upper region 17, the opening 12 has a lower region 18 with a circular cross-sectional surface corresponding to the hollow-cylindrical side surface 19, the diameter of which corresponds at least to the radial dimensions of the tenon 7 and the locking projections 11 (see FIGS. 4A-4C ). Therefore, the tenon 7 with the locking projections 11 can be inserted into the upper region 17 of the opening 12, but cannot be rotated in the upper region 17 around an axis of rotation parallel to the assembly direction (i.e., axially). This is prevented by the reduced diameter areas between the bulges 20. When the locking projections 11 reach the lower area 18 of the opening 12, which has an enlarged diameter, by further insertion of the tenon 7 into the opening 12, the tenon 7 can rotate about an axis of rotation parallel to the assembly direction, thereby allowing the tenon 7 to latch (see Figures 4A-4C). The continuous opening 12 does not have an internal thread. It is understood that the tenon 7 can have a greater or lesser number of locking projections 11.

[0042] As can also be clearly seen in Figure 2, the support element 1 has a rotation lock for fixing the rotational position of the tenon 7 in which the two locking lugs 11 are fastened. In particular, this is formed by a plug pin 21 (see Figure 3B) made of ceramic material, which is inserted into a corresponding pin receiver 22 designed to fit onto the plug pin 21. The plug pin 21 and the pin receiver 22 are arranged axially. The plug pin 21 has, for example, a circular radial cross-sectional surface. The pin receiver 22 has a circular radial cross-sectional surface. It is also conceivable that the cross-sectional surfaces of the plug pin 21 and the pin receiver 22 have different cross-sectional shapes, for example rectangular or triangular.

[0043] In the region of the disk-shaped flange 4, the pin receiving section 22, which opens onto the disk upper side 5, is formed solely by the upper part 2, but is composed of an upper part pin receiving section 23 and a lower part pin receiving section 24 at the level of the tenon 7, which are complementary to each other so as to form the pin receiving section 22 at a specific rotational position of the tenon 7, where the locking lug 11 is fastened to the lower part 3. This rotational position is fixed by the plug pin 21. In this embodiment, the upper part pin receiving section 23 and the lower part pin receiving section 24 each contribute half of the pin receiving section 22. The upper part pin receiving section 23 and the lower part pin receiving section 24 open onto the locking lug 11, so that the plug pin 21 inserted into the pin receiving section 22 can rest on the locking lug 11. Obviously, the support element 1 can also have several such plug pins 21 to form a rotation lock, each received in a corresponding pin receiving section 22.

[0044] 3A and 3B, an embodiment of oven rack element 90 of oven rack 100 from FIG. 1 is shown in perspective views before assembly of upper part 2 and lower part 3 onto shelf 80 (FIG. 3A), and after assembly onto shelf 80 (FIG. 3B). For simplicity, only one corner region of shelf 80 is shown, it being understood that support element 1 can be attached in a corresponding manner to other corner regions of shelf 80.

[0045] The shelf 80 has, for example, a circular through-hole 25 in the corner region, the diameter of which corresponds to the diameter of the tenon 7 and the locking projection 11, so that the tenon 7 can be inserted through the through-hole 25. The shelf 80 has an upper shelf part 27 with an upper shelf surface 29 and a lower shelf part 26 with a lower shelf surface 28. As shown in FIG. 3A , the lower part 3 is placed in the through-hole 25 of the lower shelf part 26, so that the opening 12 is aligned with the through-hole 25, and the lower part upper surface 16 abuts the lower shelf surface 28. Therefore, the lower part upper surface 16 (the end face of the sleeve) serves as a contact surface for the lower part 3. The tenon 7 is inserted through the through-hole 25 into the opening 12 indicated by the arrow in FIG. 3A , and the lower disk surface 9 abuts the upper shelf surface 29. Therefore, the lower disk surface 9 serves as a contact surface for the upper part 2. By rotating the tenon 7 through a predetermined rotation angle, here for example 90°, the tenon 7 can be latched in the opening 12. This is indicated by the arrow in Figure 3B. In the latched position, the plug pin 21 is inserted into the pin receiving portion 22, which is designed as a hole for fixing the rotational position of the upper part 2 or the tenon 7 relative to the lower part 3. The shelf 80 is fixed between the upper part 2 or the disk-shaped flange 4 and the lower part 3.

[0046] As shown in Figure 1, oven rack elements 90 obtained by assembling four support elements 1 on respective shelves 80 can be stacked, with the distance between immediately adjacent shelves 80 being determined by the axial dimension of the support elements 1, specifically the area of ​​the support element 1 located between the shelves 80. Considering two immediately adjacent shelves 80, the lower part 3 of each support element 1 of the upper shelf 80 rests, with its lower part surface 15, only on the upper disk surface 10 of the upper part 2 of the lower shelf 80 located below it. The centering collar 8 of each upper part 2 is suitable to be received in the downwardly opening opening 12 of the lower part 3 located above it, i.e., the opening 12 engages around the centering collar 8, in order to secure the upper part 2 against lateral sliding.

[0047] 4A to 4C show, using perspective views of the upper part 2 and the lower part 3 of FIG. 2 with a cutaway, the fastening of the tenon 7 and the formation of the rotation lock in the fastening position.

[0048] As already explained, the opening 12 comprises an upper region 17 and a lower region 18. In the upper region 17, the opening 12 has a cross-sectional surface adapted to the cross-sectional surface of the upper part 2 in the region of the tenon 7 and the two locking projections 11, so that the tenon 7 with the locking projections 11 can be inserted into the opening 12. In the lower region 18, the opening 12 has a hollow cylindrical side surface 19, the diameter of which corresponds at least to the combined radial dimension of the tenon 7 and the locking projections 11, so that the tenon with the locking projections 11 can be rotated. Due to the enlarged lower region 18, a radially inwardly projecting shoulder 30 is formed, by which the respective locking receptacles 31 for the locking projections 11 are restricted axially upward.

[0049] FIG. 4A shows the state in which the tenon 7 has been inserted into the opening 12. The locking projection 11 is already positioned in the lower region 18 of the opening 12 but has not yet been locked, i.e., the tenon 7 has not yet been rotated. FIG. 4B shows the situation after the upper part 2 or the tenon 7 has been rotated by a predetermined angle, here, for example, 90°. This is indicated by the arrow. The locking projection 11 is inserted into the locking receiver 31 by rotating the tenon 7, and the locking projection 11 is blocked by the shoulder 30 in the upward axial direction (the direction in which the tenon 7 moves out of the opening 12). This locks the upper part 2 axially to the lower part 3. FIG. 4B shows that the plug pin 21 can be inserted into the pin receiver 22 in the locked, rotated position. FIG. 4C shows a further situation in which the plug pin 21 has been inserted into the pin receiver 22.

[0050] Generally, the locking projections 11 are not pre-loaded into the locking receivers 31. Rather, the locking projections 11 are preferably received in the locking receivers 31 with axial and / or radial play. Thus, in the support element 1 attached to the shelf 80, the locking projections 11 advantageously have a small axial gap 32 (axial play) relative to the shoulder 30 and / or a small radial gap 33 (radial play) relative to the side surface 19. This makes it possible to compensate for assembly tolerances and different thermal expansions of the ceramic materials used in the oven rack element 90.

[0051] It is also conceivable that only a single locking projection 11 is arranged on the tenon 7, which can be selectively locked into one of the two locking receivers 31, arranged so that the locking projection 11 is locked into one locking receiver when the tenon 7 is rotated in one direction of rotation, and into the other locking receiver 31 when the tenon 7 is rotated in the other direction of rotation. This has the advantage that the locking projection can always be locked into the locking receiver, regardless of the direction of rotation.

[0052] 5 shows a cross section of two oven shelf elements 90 of the oven rack 100 of FIG. 1. It can be clearly seen that the lower part 3 of the support element 1 of the upper shelf 80 rests only on the upper disc surface 10 of the upper part 2 of the lower shelf 80 located below it, with its lower part surface 15. The centering collar 8 of the upper part 2 is received in the opening 12 of the lower part 3 located above it. A plug pin 21 located in the hole rests on a locking projection 11.

[0053] The oven rack 100 shown in Figure 1 can be easily attached and detached. To remove the support element 1 from the shelf 80, the plug pin 21 must be removed from the pin receptacle 22, and then the upper part 2 must be rotated relative to the lower part 3 in a direction opposite to the direction of rotation for fastening, so that the locking projection 11 disengages from the shoulder 30 and the tenon 7 can be removed from the opening 12.

[0054] The support element 1 and shelf 80 are made from a high temperature resistant ceramic material, such as silicon carbide or mullite.

[0055] As can be seen from the above description of the invention, the present invention presents a novel multi-part ceramic support element in which the upper and lower parts can be axially and detachably connected with a locking connection for securing the shelves. The drawbacks of threaded connections, particularly the risk of changing the shelf distance and position, can be advantageously avoided. This is particularly important in automated manufacturing processes, such as are typical in industrial environments, where distortions due to improper gripping and placement positions of robotic gripping arms must be avoided. [Explanation of symbols]

[0056] 1 Supporting elements 2 Upper parts 3 Lower part 4. Disc-shaped flange 5 Upper disc 6 Lower disc 7 Tenon 8 Centered collar 9 Lower disc surface 10 Upper disc surface 11 Locking protrusion 12 Opening 13 Upper part of lower part 14 Lower part of the lower part 15 Lower surface of lower part 16 Upper surface of lower part 17 Upper area 18 Lower area 19 side surface 20 Bulge 21 plug pins 22 Pin receiving part 23 Upper part pin receiving part 24 Lower part pin receiving part 25 Through hole section 26 Underside of shelf 27 Upper shelf 28 Lower shelf surface 29 Upper shelf surface 30 Shoulder 31 Locking receiving part 32 Axial gap 33 Radial gap 80 shelves 90 oven rack elements 100 oven racks

Claims

1. A multi-piece ceramic support element (1) for spacing ceramic shelves (80) of an oven rack (100), comprising an upper part (2) and a lower part (3); the upper part (2) is detachably connectable to the lower part (3) in the axial direction by a locking connection in order to fix a shelf (80) between the upper part (2) and the lower part (3); the locking connection is formed by a tenon (7) provided in one of the parts (2) and having one or more locking projections (11) protruding from the tenon (7) and an opening (12) provided in the other part (3), respectively; the tenon (7) can be inserted into the opening (12) and can rotate in the opening (12) without simultaneously moving into or against the opening (12), so that the one or more locking projections (11) can be respectively fastened in locking receivers (31) formed by the part (3) having the opening (12); A multi-component ceramic support element (1).

2. 2. The multi-component ceramic support element (1) according to claim 1, wherein the part (3) having the opening (12) is designed in the form of a sleeve and has an end face (16) that serves in particular to abut against the shelf (80).

3. 3. A multi-component ceramic support element (1) according to claim 1 or 2, wherein the part (2) having the tenon (7) has a disk-shaped region (4) having a lower disk side (6) facing the opening (12) and an upper disk side (5) facing away from the opening (12), and the tenon (7) protrudes from the lower disk side (6).

4. 4. A multi-component ceramic support element (1) according to claim 3, wherein the underside of the disc (6) is substantially flat and adapted to abut against the ledge (80).

5. 5. A multi-part ceramic support element (1) according to claim 3 or 4, wherein the upper disc part (5) has a centering collar (8) arranged to be received by the lower part (3) of a further support element (1).

6. The multi-component ceramic support element (1) according to any one of claims 1 to 5, wherein the part having the tenon portion (7) is the upper part (2) and the part having the opening (12) is the lower part (3).

7. The opening (12) has a length starting from the side where the tenon (7) is inserted into the opening (12): a cross-sectional surface in a first region (17) that corresponds to the cross-sectional surfaces of the tenon (7) and the one or more locking projections (11), whereby the tenon (7) is not rotatable within the first region (17); and 7. The multi-component ceramic support element (1) according to claim 1, wherein a second region (18) adjacent to the first region (17) has a hollow cylindrical cross-sectional surface having a diameter at least corresponding to the combined diameter of the tenon (7) and the one or more locking projections (11), whereby the tenon (7) is rotatable within the second region (18).

8. 8. The multi-component ceramic support element (1) according to claim 1, wherein the one or more locking projections (11) are each designed in the form of a flange projecting radially outward, and the one or more locking receivers (31) are each designed in the form of a shoulder projecting radially inward.

9. The multi-component ceramic support element (1) according to any one of claims 1 to 8, wherein the one or more locking projections (11) are each fastened with axial play and / or radial play in the locking receiving portion (31).

10. 10. The multi-component ceramic support element (1) according to any one of claims 1 to 9, comprising at least two locking receiving portions (31), the two locking receiving portions (31) being arranged so that a locking projection (11) can be fastened by one of the two locking receiving portions (31) by rotating the tenon portion (7) in one or the other rotational direction, in particular by rotating each by the same rotation angle, for example 90°.

11. The multi-component ceramic support element (1) according to any one of claims 1 to 10, comprising a rotation lock for fixing the rotational position of the tenon (7) in which the one or more locking projections (11) are fastened.

12. 12. The multi-component ceramic support element (1) according to claim 11, wherein the rotation lock is formed by one or more plug pins (21), each of which is received in a pin receiving portion (22), which is formed at least in part by the upper part (2) and the lower part (3) together and has a shape that fits onto the plug pins (21).

13. 13. A multi-component ceramic support element (1) according to claim 12, wherein the one or more plug pins (21) are each mounted on a locking projection (11).

14. An oven rack element (90) comprising a shelf (80) having at least one through hole (25) and at least one multi-component support element (1) according to any one of claims 1 to 13, wherein the shelf (80) is fixed between the upper part (2) and the lower part (3).

15. An oven rack (100) comprising a lower shelf (80) and at least one upper shelf (80), wherein the lower shelf (80) is fixed to at least one support element (1) according to any one of claims 1 to 13 between the upper part (2) and the lower part (3), and the at least one upper shelf (80) is fixed to at least one support element (1) according to any one of claims 1 to 13 between the upper part (2) and the lower part (3), and the lower part (3) of the at least one support element (1) to which the upper shelf (80) is fixed abuts only the upper part (2) of the support element (1) to which the lower shelf (80) is fixed.

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