baking tray

Abstract

The invention relates to a baking tray for industrially operated baking plants comprising a frame and an inlay, wherein the baking tray is designed to be flat and the inlay is made of a perforated sheet of aluminum or an aluminum alloy with a thickness of no more than 1.3 mm, in particular no more than 1.15 mm, or from expanded metal made of aluminium or an aluminium alloy, or is formed from a grid network arranged under tension, and the frame consists of a frame made of a rectangular cross-section hollow steel profile or The baking tray is made of a high-temperature plastic and features two wide and two narrow walls. The wide walls are wider than the narrow walls, and the narrow walls are arranged approximately parallel to the inlay, while the wide walls are arranged approximately perpendicular to the inlay. Compared to conventional baking trays, such a tray is very lightweight and therefore has a low heat capacity. This significantly reduces energy consumption in industrial baking lines.

Description

[0001] The present invention relates to a baking tray for industrially operated baking plants, in particular baking lines or industrial baking chambers.

[0002] Industrially operated baking systems, such as a baking line, are known, for example, from EP 0710441 B1. A baking line is a tunnel-shaped system into which a baking tray loaded with raw goods is inserted at one end. The baking tray is then moved through the baking line, which maintains a predetermined temperature profile, so that the goods are baked. At the exit end of the baking line, the baking tray is removed and often transferred to a cooling or freezing unit so that the freshly baked goods are frozen or flash-frozen as quickly as possible. The baked goods can be removed from the baking tray before freezing. However, as a rule, after a short cooling period, the baking tray and the baked goods are immediately transferred to a freezing station, so that the baked goods are frozen solid on the tray.

[0003] These baking trays typically consist of a frame and an inlay, usually a perforated sheet. The frame is usually made of four stainless steel struts welded together at the corners. The inlay is attached to the frame with rivets. Baking trays for industrial baking systems or ovens have a rectangular shape when viewed from above. The inlay is made of a material such as aluminum. However, this design has several disadvantages because the stainless steel frame and the inlay, being made of different materials, have different coefficients of thermal expansion, which can lead to unwanted bulging of the inlay and loosening of the rivets.

[0004] The inlays need to be replaced at regular intervals (approximately every 1 to 1.5 years) because the coated surface wears down due to repeated heat treatment. Some of the inlays have non-stick coatings (especially PTFE) that degrade over time. Dough residue can also become baked onto the surface of the inlays. When an inlay is replaced, it is detached from the frame. New holes are drilled in the frame so that the new inlay can be attached with rivets. Typically, about five inlays can be used with one frame. After that, so many holes are drilled in the frame that it can no longer be used.

[0005] From EP 2 394 514 A1, a baking tray for industrially operated baking systems is known, comprising a stabilizing and / or support frame that supports the inlay of the baking tray from below and is connected to the inlay by means of at least one fixing device. The fixing device is formed by a sliding guide by means of which the inlay can be slid onto the stabilizing and / or support frame. This allows the inlay to be replaced easily and quickly, and the stabilizing and / or support frame can be used for any number of cycles.

[0006] In WO 2023 / 037351 A1, another baking tray is described which has an interchangeable inlay that can be attached to a support frame by means of clamps. The inlay can be flat. However, it can also be provided with parallel indentations.

[0007] EP 2708129 B1 describes another baking tray in which the inlay is attached to the support frame by crimping or crimping tabs formed on the inlay around a projection. The baking tray can be flat or molded.

[0008] Another tray with a trough is described in WO 2015 / 044588 A1, in which a slot is formed between each of the individual troughs.

[0009] US patent 2022 / 0322682 A1 describes a trough baking tray in which an inlay is suspended on a support frame. The inlay forms a series of parallel troughs. The upwardly projecting areas between the individual troughs are each supported by a crossbeam of a support frame. The inlay is made of expanded metal sheet with micro-openings that form a metal grid. The expanded metal sheet is produced by cutting and stretching a metal sheet. The micro-openings have openings between 130 and 750 µm. Due to the micro-openings, the expanded metal sheet has an open area that comprises between 17 and 60% of the total surface area of ​​the sheet.

[0010] US patent 2017 / 0318820 A1 discloses another trough baking tray, which is laminated with a fluororesin film 75 to 500 µm thick onto a metal substrate 1 by heat bonding and into which numerous holes are punched. The baking tray is said to have excellent release properties, since the dough only comes into contact with the fluororesin film during the bread baking process.

[0011] Another trough baking tray is known from WO 2005 / 092007 A2, which is formed from a corrugated sheet and two strips attached to the end faces of the sheet.

[0012] EP 2 014 171 B1 shows a trough baking tray which has special securing elements for attaching an inlay to a frame.

[0013] In WO 2005 / 3430 A1, a baking tray is disclosed which has a multitude of openings with an area between 0.07 mm 2 and 1.77 mm 2The sheet metal has an opening area of ​​between 9 and 30 percent of its surface area. The openings preferably consist of micro-perforations that are evenly distributed over the perforated part of the sheet metal and have a substantially circular shape with a diameter between 0.30 and 1.5 mm.

[0014] The WO 2009 / 123451 A1 reveals a baking tray that closes as flat as possible at the edge area, so that it can be cleaned easily and reliably.

[0015] EP 2826373 A1 relates to an inlay for a baking tray made of a hot-dip aluminized steel sheet and a support structure for the inlay made of a ceramic material that has a lower thermal conductivity than the steel sheet of the baking tray. Such a baking tray allows for energy-efficient use and is also suitable for large-scale industrial applications.

[0016] FR 2097608 A5 discloses a baking mold for shaping bread or cake dough, consisting of a glass fiber mesh that is at least 50% ventilated and impregnated with silicone rubber. The baking mold is lighter, easier to handle, and more porous than baking trays coated with a PTFE layer or a silicone rubber-treated fabric. The molds preferably have the form of successive racks supported by a frame or stand and consist of a glass fiber fabric of approximately 1-3 min.

[0017] German utility model DE 20 2013 004 320 U1 describes a baking tray designed as an insert tray, in which a baking tray-side support area is made of abrasion-resistant and rust-free stainless steel.

[0018] German utility model DE 20 2010 007 826 U1 discloses a baking tray for industrially operated baking systems, comprising an inlay connected to a frame supported from below. The inlay has an engagement element projecting from its underside, which, when placed on the frame, engages the frame in a form-fitting manner in certain areas and / or essentially surrounds the frame from the outside in a form-fitting manner, at least in certain areas. The engagement element may be provided with elongated holes into which rivets are inserted to connect the inlay to the frame.

[0019] The invention is based on the objective of creating a baking tray that allows for very efficient operation, particularly in a production line.

[0020] Another objective of the invention is to create a baking tray that has a long service life.

[0021] Another task is to create a baking tray that is easy to handle and maintain.

[0022] One or more of the problems are solved by a baking tray according to one of the independent patent claims. Advantageous embodiments are listed in the dependent claims.

[0023] According to a first aspect of the present invention, a baking tray for industrially operated baking machines is provided, comprising a frame and an inlay, wherein the baking tray is designed to be flat and the inlay - made of perforated aluminum sheet with a thickness of no more than 1.3 mm, in particular no more than 1.15 mm, or - made of expanded metal made of aluminium or an aluminium alloy, or. - is formed from a grid, and The frame is formed from a rectangular-section hollow steel profile, which has two broad side walls and two narrow side walls, wherein the broad side walls are wider than the narrow side walls and the narrow side walls are arranged approximately parallel to the inlay and the broad side walls approximately perpendicular to the inlay.

[0024] The construction of an inlay from thin perforated sheet metal, expanded metal, or a mesh results in a significantly lighter inlay compared to conventional inlays. This reduces the overall mass of the baking tray. A lighter baking tray also means lower heat capacity, so it absorbs less heat when heated. This, in turn, requires less cooling power when refrigerated. In industrial bakery production, this leads to a considerable reduction in energy consumption. Furthermore, the baking tray heats up and cools down much faster than a conventional one, thus accelerating the baking and cooling processes. Additionally, steeper temperature ramps can be used compared to conventional baking trays, which is advantageous for certain baked goods.

[0025] Since the frame is formed from a hollow profile with a rectangular cross-section, whose broad side walls are arranged approximately perpendicular to the inlay, the frame has a slender profile that extends far away from the inlay. Due to its tall geometry, such a profile possesses high stiffness against loads perpendicular to the inlay. This slender and tall profile thus results in significant stiffening of the inlay in its main load direction, while the frame itself, due to its slim design, is considerably lighter compared to conventional frames.

[0026] The frame is made of steel. Steel is a strong and, in particular, abrasion-resistant material with high rigidity. The inlay is made of aluminum or an aluminum alloy if it consists of perforated sheet metal or expanded metal. Compared to steel, aluminum is a significantly better heat conductor and therefore results in considerably better baking quality compared to a comparable steel inlay. However, aluminum has significantly lower abrasion resistance than steel, which is why it is less suitable for the frame, which is in constant friction with various components of an industrial oven.

[0027] A tensioned grid can be extremely lightweight and flexible, yet the tensioning mechanism provides the necessary strength to support the desired load of baked goods without causing excessive deformation that would cause the goods to slip on the inlay. Such a grid also offers the advantage of extremely low heat capacity and a high ratio of openings to grid area, ensuring that the baked goods are heated almost as effectively on their underside, which rests on the grid, as on any other side facing away from the inlay.

[0028] The lighter weight makes the baking tray easier for employees to handle. This improves workplace safety.

[0029] Baking trays for industrial baking lines are, in plan view, flat, rectangular bodies with a length of approximately 2 m and a width of approximately 75 cm to 1 m. The baking trays can be of different sizes and have a width of at least 0.6 m and / or a length of at least 0.8 m and, in particular, at least 1.5 m.

[0030] The broad side wall of the frame preferably has a width of at least 20 mm, in particular at least 25 mm or at least 30 mm and / or the broad side wall of the frame has a width of at least 5 mm and in particular at least 10 mm and preferably not more than 20 mm and in particular not more than 15 mm.

[0031] This slim frame constitutes a further independent aspect of the present invention, wherein such a baking tray for industrially operated baking systems comprises a frame and an inlay, the frame being formed from a hollow profile with a rectangular cross-section, having two broad side walls and two narrow side walls. The baking tray is characterized in that the broad side walls are oriented approximately perpendicular to the plane of the inlay and are many times, in particular three times, larger than the narrow side walls.

[0032] This geometry gives the frame high stiffness against loads applied perpendicular to the plane of the inlay. Furthermore, due to its narrow side walls, the frame can be made lighter compared to conventional frames. Preferably, the frame is made of steel.

[0033] The frame can be formed from a single, continuous metal tube. The metal tube is bent at the corners. For this design, a profile with broad side walls that are many times larger than the narrow side walls is advantageous. Such "bent corners" are very rigid and give the frame high strength. The continuous metal tube is preferably joined to its ends by welding or brazing in the area of ​​one of the longitudinal struts, with the joint preferably being more than 10 cm and, in particular, more than 20 cm from the nearest corner.

[0034] Instead of a continuous metal tube, the frame can also be formed from several straight frame sections, with a so-called stacking corner provided at each corner. Such a stacking corner is a solid, roughly cuboid body with a bottom and a top side, the bottom side being located on the underside of the frame and the top side on the top. The top side has an upward-projecting tenon, and the bottom side has a recess to receive the tenon. The tenon has a roughly conical shape, so that when several stacking corners are stacked, the tenons engage in the corresponding recess and self-center. Of course, the recess can also be conical, and the tenon can then be conical or not.At each such stacking corner, two frame sections are attached at right angles to each other, for example by means of a material-bonded connection such as a weld or solder joint. Such a frame thus consists of four stacking corners and four frame sections, each extending between two stacking corners.

[0035] The stacking corners are either materially bonded to the longitudinal and transverse struts of the frame or connected by means of a plug connection, whereby in the case of a plug connection corresponding plug projections are formed on the stacking corners.

[0036] The provision of such stacking corners allows several baking trays to be stacked on top of each other, with the stacked trays aligned and fixed in position. This allows a large number of baking trays to be stacked on top of each other and thus stored safely and without risk.

[0037] The proportion of the area of ​​the holes to the total area of ​​the inlay is preferably at least 25%, more particularly at least 35% or at least 45%. If the inlay is supported by the frame, it is even possible to increase the proportion of the area of ​​the holes to at least 50% or at least 55%.

[0038] The inlay can also be made of expanded metal. The expanded metal has an openness of preferably more than 50%, particularly more than 60%, and particularly more than 70%. The expanded metal is preferably made of aluminum or an aluminum alloy.

[0039] The inlay can also be formed from a grid.

[0040] The grid can be a rigid mesh, for example, made of metal wires, especially aluminum wires. The individual wires can cross over each other alternately, like in a woven fabric. However, the wires can also be joined at the contact points by means of a soldered or welded connection.

[0041] The grid can also be made of a flexible grid, such as a fabric made of temperature-stable filaments.

[0042] The individual filaments of the fabric can be, for example, glass fibers. The glass fibers can be coated or impregnated with a plastic. Each filament can consist of a single, elongated fiber. Instead of glass fibers, other temperature-stable fibers, particularly mineral fibers such as silicon carbide fibers, can also be used. However, a single filament of the fabric can also comprise multiple fibers. These fibers can run parallel to each other within the filament. Such a fiber strand is called a roving. The multiple fibers can also be braided together. Such a fiber strand is called a yarn. The multiple fibers are preferably impregnated with a temperature-stable plastic, such as PTFE, silicone, or epoxy.

[0043] An inlay, especially one made of such a fabric, has an extremely low weight and extremely low heat capacity compared to conventional baking tray inlays. This is very advantageous for the efficiency of the baking tray during operation.

[0044] A flexible wire mesh is preferably held under tension within the baking tray. This allows for a large baking tray with, for example, a surface area of ​​more than 1 m². 2 and especially more than 1.5 m 2 A flexible mesh tray is provided that is both very lightweight and possesses the necessary strength to reliably hold a large number of dough pieces. Such a flexible tray can accommodate the desired baked goods without sagging excessively and without the baked goods slipping due to flexing of the tray.

[0045] The larger the perforation or opening, the better the hot air can reach the baked goods or dough pieces from below the baking tray in the production line. For certain baked goods, a high degree of opening is very advantageous and increases the quality of the product. This allows for very even baking on all sides of the product.

[0046] The frame can have a compartment consisting of at least one transverse and / or at least one longitudinal brace to support the inlay. Multiple transverse and / or longitudinal braces are also possible. Such a compartment for supporting the inlay allows the use of a thin-walled inlay with low inherent rigidity, thus further reducing the weight of the entire baking tray.

[0047] According to another aspect, the invention comprises a baking tray for industrially operated baking systems with a frame and an inlay. The baking tray is characterized in that the frame has a compartment made up of several transverse and longitudinal struts for supporting the inlay.

[0048] By providing such a framework of several transverse and longitudinal struts to support the inlay, very thin-walled inlays with low inherent rigidity can be used, ensuring that the inlays only yield minimally when the baking tray is loaded with baked goods. When loading a baking tray with baked goods, the total mass of the baked goods is approximately 5 to 7 kg / m². 2The weight is evenly distributed across the baking tray. With this load, the maximum deflection of the inlay compared to its unloaded state should not exceed 10 mm, and in particular, not more than 5 mm at any single point on the baking tray. Alternatively, the baking tray can be dimensioned so that the maximum deflection at any point does not exceed 2.5 mm compared to its unloaded state. The compartments provide sectional support for the inlay, ensuring that only small sections of the entire inlay are subject to uniform deflection when loaded. The smaller these sections, the less deflection there is.

[0049] In principle, the transverse and / or longitudinal struts should be spaced as evenly apart as possible.

[0050] The transverse and / or longitudinal struts are preferably each formed from a metal or plastic strut with a specific profile. The profiles can be, for example, an I-profile, L-profile, U-profile, or a round profile. A rod in the form of a round profile is also referred to as a wire. The round profile generally has a circular cross-section, but can also have a cross-section that deviates slightly from the circular shape, such as an elliptical or oval cross-section, or, similar to a flat wire, a cross-section with two circular segments connected by a cuboid section. The profiles are preferably designed and arranged in the baking tray in such a way that they possess high stiffness, particularly under a load perpendicular to the plane of the baking tray. Therefore, they have a greater extent, especially in the direction perpendicular to the plane of the baking tray, than transversely to the longitudinal direction of the respective strut.The extension in the direction perpendicular to the plane of the baking tray is preferably at least twice or, in particular, at least three times as much as transverse to the longitudinal direction.

[0051] The transverse and / or longitudinal struts can be connected or interlocked at their intersection points. A connection can be formed, for example, by a material bond such as soldering or welding. In the case of interlocking, at least one of the transverse and / or longitudinal struts has a recess at the respective intersection point in which the other transverse and / or longitudinal strut is received at the respective intersection point in a form-fitting manner. Preferably, such a recess is formed on both the transverse and the longitudinal strut at the respective intersection point.

[0052] Preferably, in particular, the cross braces are made of an L-profile and the longitudinal braces of a round profile (= wire) or the longitudinal braces of an L-profile and the cross braces of a round profile.

[0053] However, the transverse and / or longitudinal struts can also each be formed from a round profile, or the transverse and / or longitudinal struts can each be formed from a strip or I-profile, with the I-profiles having slots at the respective intersection points, so that the I-profiles crossing at the intersection points are interlocked with each other.

[0054] According to a further aspect of the present invention, a baking tray for industrially operated baking systems is provided, comprising a frame and an inlay. The baking tray is characterized in that the inlay is floatingly mounted on the frame.

[0055] Such a floating mounting of the inlay on the frame allows the inlay and frame to be made of different materials. This enables the inlay and frame to be subject to different thermal expansion rates without causing stress between them. Another advantage of the floating mounting is that the inlay is easily replaceable, especially if the floating mounting is designed to be removable on one side of the frame. In this case, the inlay can be easily detached from the frame by sliding it within the plane of the baking tray and replaced with a different inlay.

[0056] In conventional industrial baking trays, the inlays are attached to the frame using rivets. Replacing an inlay requires loosening the rivets and drilling new holes in the frame for the new rivets. Therefore, inlay replacement can only be performed by specially trained personnel. In practice, this means that the baking trays must be sent to the manufacturer for inlay replacement, who then expertly processes them. Replacing inlays on-site is generally not possible. With the baking tray according to the invention, this is possible, enabling bakeries to replace the inlays themselves, as explained below.

[0057] To create such a floating mounting, the frame can have U-shaped rails on at least two opposing struts, with their openings facing each other. The inlay can be supported in the U-shaped rails with its corresponding edge areas. A releasable fixing element can be arranged on the frame, with which the inlay, which is slidably mounted in the U-shaped rails, can be fixed.

[0058] This releasable fixing element can be a releasable U-shaped rail that can be fixed to the frame with a screw, latch, or snap connection. Alternatively, the releasable fixing element can also be a screw, latch, or snap connection that directly fixes the inlay to the frame. In the area of ​​the fixing element, the inlay can then be fixed in place, i.e., non-floating, provided that a floating support is provided on at least two opposing frame members, and preferably on all three other members of the rectangular frame (as viewed from above).

[0059] According to another aspect of the present invention, a baking tray for industrially operated baking systems is provided, comprising a frame and an inlay. This baking tray is characterized by the fact that the inlay has a surrounding plug-in frame, which is detachably connected to the frame. This design of the baking tray allows for easy removal and attachment of the inlay to the frame. Both the inlay and the frame can be easily handled independently of each other. The inlay can be attached to the frame by means of a clamping connection, a screw connection, or a snap-fit ​​connection. Such an inlay can also be replaced on-site.

[0060] The plug-in frame can be designed so that, when assembled, it rests against the inward-facing surface of the frame and has a complementary outer surface to this inward-facing surface. Such a plug-in frame can also be called an inner frame, since it is located within the actual frame, which can also be called the main frame.

[0061] However, the plug-in frame can also be designed in such a way that it fits snugly against an outward-facing surface of the frame or main frame and has a complementary shape to it. The plug-in frame can then be referred to as an outer frame.

[0062] The plug-in frame, whether in the form of the inner or outer frame, can form a friction-fit connection with the main frame, which can preferably be secured by means of further connecting elements, such as clamping connections, screw connections, or snap-fit ​​connections. However, some play may also exist between the plug-in frame and the main frame.

[0063] Such a plug-in frame allows for easy replacement of the inlay on the frame or main frame, provided the inlay is firmly attached to the plug-in frame. Furthermore, a flexible, non-rigid inlay can be provided on the plug-in frame, which is held under tension. In this case, the inlay and the plug-in frame together form a consumable part that is easily and quickly replaceable and, due to the minimal material required, can be manufactured cost-effectively. A compartment can also be formed on the plug-in frame, in which case the inlay can be attached to the frame or be separate from it.

[0064] For such a design of the baking tray with plug-in frame and main frame, it is advantageous if the main frame has a narrow and high cross-section, as explained above.

[0065] The plug-in frame may be equipped with locking devices that interact with corresponding counter-locking devices on the frame to secure the plug-in frame to the frame. The locking devices, particularly on the plug-in frame, may also include locking recesses, especially longitudinally extending elongated slots, and the counter-locking devices may be spring-loaded locking protrusions, especially spring-loaded balls or locking lugs, that engage in the corresponding locking recesses. This allows the inlays to be easily and repeatedly detached from and reattached to the frame. With such locking connections, the connection between the inlays and the frame can be easily disconnected and re-established without special tools.This means that the inlays and frames can be easily separated from each other, for example for cleaning, and the individual components of the baking tray can be easily cleaned independently of each other, with all surfaces freely accessible.

[0066] As explained earlier, conventional baking trays typically attach their inlays to the frame using rivets. These trays require regular replacement, which involves loosening the rivets and drilling new holes in the frame walls to insert new rivets for the inlays. In practice, it has been found that no more than five or six inlays can be attached to a single frame. After that, the frame has so many holes that there is no longer enough space for adequate rivet attachment. It's important to note that these conventional frames are significantly wider than the slim frames described above, thus providing more room for rivet holes. With a detachable connection between the inlay and the frame, it is unnecessary to drill these rivet holes.Therefore, the inlays on the frame can be replaced as often as desired, and the frame's lifespan is practically unlimited in this respect. Furthermore, such a detachable connection between the inlay and the frame allows for a significantly slimmer and thus lighter frame design compared to conventional frames. Another advantage is that no rivets can come loose during operation. This is a problem that operators of industrial ovens address by installing metal detectors that can detect baked goods containing metal fragments.

[0067] A further aspect of the present invention is therefore to provide a baking tray for industrially operated baking plants with a frame and an inlay, wherein the frame is formed from a hollow profile with a rectangular cross-section, having two broad side walls and two narrow side walls. The baking tray is characterized in that the inlay is connected to the frame by detachable connecting means.

[0068] The term "releasable fasteners" refers to non-destructive, detachable fasteners that remain essentially unchanged after the inlay has been removed and can be reused to attach another inlay to a frame. Rivets and bonded joints, such as welds or soldered joints, are not considered releasable fasteners in this sense.

[0069] The detachable fasteners can be any of the fasteners already described above, such as those providing floating support. However, they can also be any other detachable fasteners, such as screw connections or other snap-fit ​​or latching fasteners. The detachable fasteners can be designed, for example, to connect the plug-in frame described above to the main frame, or to directly connect the inlay to the frame or main frame.

[0070] The frame preferably has the slim shape described above, in which the broad side walls are several times, in particular 3 times, larger than the narrow side walls and the broad side walls are aligned approximately perpendicular to the plane of the inlay.

[0071] The detachable fasteners thus allow not only for easy and quick replacement of the frame inlays, but also for a narrow, lightweight frame design that is rigid with respect to the main load of the inlay. Such a detachable connection therefore indirectly contributes to weight reduction of the entire baking tray.

[0072] The inlay can be an integral part of the plug-in frame and attached to the main frame together with the plug-in frame.

[0073] The inlay can also be designed independently of the frame. This design is particularly useful when the frame forms an inner frame relative to the main frame, and the main frame forms a corresponding outer frame, and the frame or inner frame supports the compartment described above. In this case, the compartment is independent of the main or outer frame. The inlay can be attached to the upper surface of the main or outer frame, for example, using the floating mounting method described above. Alternatively, the inlay can be provided with strips that extend approximately perpendicular to the plane of the inlay at its edges, allowing it to be positioned and fixed in the area between the inner and outer frames.

[0074] The inner frame can be formed from a hollow profile with a rectangular cross-section, a continuous sheet metal strip, or a continuous profile. The profile can be a U-shaped profile with its opening facing inwards, or, for example, an extruded profile that has a hollow profile or a crimped profile at its upper and lower edges.

[0075] The baking trays described above are essentially made of metal, with the frame primarily made of steel, and in particular nickel-chromium steel, and the inlay made of aluminum or an aluminum alloy (excluding the grid). Within the scope of the invention, parts or the entire baking tray can also be made of high-temperature-resistant plastic. High-temperature-resistant plastics include, for example, PEEK or glass-fiber-reinforced PEEK. Other suitable high-temperature-resistant plastics are perfluoroalkoxy copolymers (PFA), polyimide, polyamide-imide (PAI), polysulfone (PSU), polyethersulfone (PES), polyphenylsulfone (PPSU), polyvinylidene fluoride (PVDF), polyetherketone (PEK), or polytetrafluoroethylene (PTFE). Due to the lower strength of plastic compared to steel, it is advantageous to construct the frame from thick-walled struts or from a solid piece. The frame is preferably designed to be slim, as explained above.

[0076] The longitudinal and transverse struts of the compartment can also be made of high-temperature-resistant plastic; in particular, the compartment can also be manufactured in one piece. Such a one-piece compartment can be produced, for example, by injection molding. It can also be advantageous to provide several segments of such a compartment. These can be manufactured independently of one another.

[0077] Such a plastic compartment can be connected to the frame using screw connections, snap-fit ​​connections, or plug-in connections. The connections can be designed with some play relative to the frame. This is particularly advantageous when the compartment is made of a different material than the frame, resulting in different coefficients of thermal expansion (e.g., plastic compartment and steel frame, or aluminum or aluminum alloy compartment and plastic frame).

[0078] The baking trays for industrial baking lines described above have a width of at least 0.6 m and / or a length of at least 0.8 m, and in particular at least 1.5 m. The inventions described above, or individual aspects thereof, especially the design of the inlays, can also be used in so-called back-off baking trays. Back-off baking trays are primarily used in vending machines in retail outlets for finishing pre-baked goods. Since the product is already pre-baked, the surface requirements for back-off baking trays are lower than for baking trays in industrial baking lines. Therefore, back-off baking trays are generally not designed with replaceable inlays. However, back-off baking trays can, as described above, be fitted with inlays made of expanded metal or mesh. The inlay can be supported by a framework.Since the back-off baking tray is smaller than the baking tray for an industrial baking line, the back-off baking trays can also be designed without compartments.

[0079] As explained above using the baking trays for industrial baking lines as an example, back-off baking trays can also be made entirely or partially of plastic.

[0080] A back-off baking tray measures approximately 0.4 m x 0.6 m. Back-off baking trays can be manufactured in various sizes and have a width of at least 0.3 m and / or a length of at least 0.5 m. They typically have a width of no more than 0.6 m and / or a length of no more than 1 m.

[0081] The invention is explained in more detail below by way of example with reference to embodiments shown in the drawings. The drawings show: Fig. 1a A first embodiment of a baking tray according to the invention in a top view, wherein the baking tray has a perforated sheet which is not included in this illustration so that the other elements of the baking tray can be seen, Fig. 1b the baking tray from figure A1a in a sectional view along the section line BB in Fig. 1a, Fig. 1c an enlarged view of the left edge of the baking tray from Fig. 1b, Fig. 1d an enlarged representation of the view from Fig. 1b in the area of ​​a cross brace, Fig. 1e the baking tray Fig. 1a in a sectional view along line AA, Fig. 1f an enlarged detail view of the left edge of the baking tray in the view from Fig. 1e, Fig. 1g an enlarged view of the baking tray made of Fig. 1e in the area of ​​a longitudinal strut, Fig. 2a the baking tray Fig. 1a in a perspective view from a slightly elevated angle, Fig. 2b an enlarged view of a corner area of ​​the baking tray according to Fig. 2a, Fig. 2c an enlarged view of the connection area between a longitudinal strut and a transverse strut, Fig. 2d an enlarged representation of an intersection point between a longitudinal strut and a transverse strut of the baking tray according to Fig. 2a, Fig. 2e a section of the inlay, which is designed as a perforated sheet, Fig. 3a a second embodiment of a baking tray according to the invention in a top view, wherein the baking tray has a perforated sheet which is not included in this illustration so that the other elements of the baking tray can be seen, Fig. 3b the baking tray Fig. 3a in a sectional view along line AA in Fig. 3a, Fig. 4a an outer frame of the baking tray according Fig. 3a in top view, Fig. 4b a longitudinal frame profile of the outer frame according to Fig. 4a with a view from the inside towards the longitudinal frame profile, Fig. 4c a cross frame profile of the outer frame according to Fig. 4a in side view with a view from the inside towards the cross frame profile, Fig. 4d the longitudinal frame profile or the transverse frame profile according to Fig. 4b or Fig. 4c in cross-section, Fig. 4e-4g a stacking corner of the outer frame after Fig. 4a in a side view, top view and section view, Fig. 5a the perforated tray of the baking tray Fig. 3a in top view, Fig. 5b the perforated sheet made of Fig. 5a in a side view looking towards a transverse side of the perforated sheet, Fig. 5c a representation of a corner area of ​​the perforated sheet made of Fig. 5b in enlarged view, Fig. 5d a longitudinal strip of the inlay of the baking tray made of Fig. 3a in side view, Fig. 5e the longitudinal strip from Fig. 5D in a frontal view, Fig. 6a an inner frame with compartments of the baking tray according to Fig. 3a in top view, Fig. 6b the inner frame in side view looking towards the long side, whereby in the middle area, the inner frame is partially cut away, Fig. 6c a connection point of the inner frame with a support profile of the compartment in plan view, Fig. 6d and Fig. 6e the support profile from the Fig. 6c in a side view and in a cross-sectional view, Fig. 6f a support plate of the compartment in a side view. Fig. 7a a third embodiment of a baking tray according to the invention in a top view, wherein the baking tray has a perforated sheet which is not included in this illustration so that the other elements of the baking tray can be seen, Fig. 7b the baking tray Fig. 7a in a sectional view along line CC in figure C1a, Fig. 8a an outer frame of the baking tray according Fig. 7a in the top view, Fig. 8b a longitudinal frame profile of the outer frame according to Fig. 8a looking from the inside at the longitudinal frame profile, Fig. 8c a sectional view of the outer frame according to Fig. 8a along the section line BB in figure C2b, Fig. 8d an enlarged representation of the right edge of the view from Fig. 8c, Fig. 8e a sectional view of a missing printed piece, which is located in the outer frame after Fig. 8a is used, Fig. 8f a support plate of the outer frame according to Fig. 8a in side view, Fig. 8g the support plate according to Fig. 8f in a frontal view, Fig. 8h a reinforcement plate of the outer frame after Fig. 8a in a side view, Fig. 8i the reinforcement plate after Fig. 8h, in a frontal view, Fig. 9a an inlay of the baking tray according to Fig. 7a in the top view, Fig. 9b the inlay according to Fig. 9a in side view, Fig. 9c an enlarged representation of the right edge of the view from Fig. 9b, Fig. 10a a compartment with transverse and longitudinal struts in a perspective view, Fig. 10b a crossing point of the compartment according to Fig. 10a in enlarged view, Fig. 11a a fourth embodiment of a baking tray according to the invention in a top view, wherein the baking tray has a perforated sheet which is not included in this illustration so that the other elements of the baking tray can be seen, Fig. 11b the baking tray Fig. 11a in a sectional view along the section line AA in Fig. 11a, Fig. 11c an enlarged representation of the right edge of the view from Fig. 11b, Fig. 11e an enlarged view of a corner area from Fig. 11a, Fig. 12a a longitudinal strip of the inlay of the baking tray made of Fig. 11a in side view, Fig. 12b the longitudinal strip from Fig. 12a in frontal view, Fig. 13a an outer frame of the baking tray according Fig. 11a in the top view, Fig. 13b the outer frame to Fig. 13a in a sectional view along the section line AA in Fig. 13a, Fig. 14a a compartment formed from a wire mesh in the top view of the baking tray according to Fig. 11a, Fig. 14b the compartment made of Fig. 14a in a side view, Figure D4c shows an enlarged view of an area of ​​the side view of the compartment with an eyelet of a transverse wire, Fig. 14d an enlarged side view of the compartment Fig. 14b on the right edge, which shows an angled longitudinal wire, Fig. 15a a cross wire in side view, Fig. 15b the cross wire according to figure D5a in the front view, Fig. 16 a longitudinal wire of the compartment in a side view, Fig. 17a a support plate in a view from below, Fig. 17b the support plate from figure D7a in a front view, Fig. 18 a section of a perforated sheet in top view, Fig. 19 a section of expanded metal in top view, and Fig. 20 a section of a grid in top view. Fig. 21a a circumferential inner frame with a grid in front of the clamps of the grid in the inner frame in cross-section, Fig. 21b the surrounding inner frame Fig. 21a after the clamps of the grid in the inner frame in cross-section, Fig. 21c the surrounding inner frame Fig. 21a with the grid in top view, Fig. 22 another inner frame in cross-section.

[0082] A first embodiment of a baking tray 1 for industrially operated baking plants is described below using the following as an example: Fig. 1 a to 2e explained.

[0083] The baking tray 1 consists of a frame 2 and an inlay 3 ( Fig. 2e) formed, wherein a compartment 4 is arranged in frame 2, which serves to support the inlay 3. The frame 2 ( Fig. 1a or Fig. 2a) is rectangular in plan view, consisting of two longitudinal side profiles 5 and two transverse side profiles 6. The longitudinal side profiles 5 and transverse side profiles 6 each have a rectangular hollow profile in cross-section with two opposing narrow side walls 7 ( Fig. 1c, Fig. 1f). In the present embodiment, the broad side wall 8 has a width or height of 30 mm and the narrow side wall 7 has a width or height of 10 mm. The profiles of the longitudinal side profiles 5 and the transverse side profiles 6 can also be dimensioned differently. Preferably, the width of the broad side walls 8 is n times that of the narrow side wall 7, where n is at least 1.5 or at least 2, and preferably at least 2.5.

[0084] Frame 2 is formed from a single, continuous metal tube. The metal tube is bent at the corners 47° ( Fig. 2b) The surrounding metal tube is bonded to the longitudinal side profiles 5 of the frame 2 by means of a material connection, for example by welding or brazing. The frame 2 thus forms a monolithic body. Although the profile itself is very slender, such a frame 2 possesses high rigidity.

[0085] Frame 2 is made of stainless steel, in particular chromium-nickel steel.

[0086] In frame 2, the compartment 4 is formed by several transverse struts 9 and longitudinal struts 10. In the present embodiment, the transverse struts 9 are designed as an L-shaped support profile 9 ( Fig. 1d), which have upwardly open recesses or notches 11 at regular intervals in the upper edge region. The longitudinal struts 10, which are formed from wire elements with a circular cross-section, are located in these notches 11 ( Fig. 1g). Both the cross braces 9 and the longitudinal braces 10 are attached to the inner sides of the longitudinal side profiles 5 and transverse side profiles 6 of the frame 2 by means of a material-bonded connection (soldering or welding). In this way, the compartment 4, which is firmly connected to the frame 2, contributes significantly to the strength and rigidity of the baking tray 1.

[0087] The crossbars 9 and the longitudinal bars 10 are arranged flush with each other at their upper edges, so that they can equally support the inlay 3 from below.

[0088] On the longitudinal side profiles 5 of the frame 2, U-shaped longitudinal rails 12 are attached ( Fig. 1c) attached to the upper side of the longitudinal profiles 5 such that the openings of the U-shaped longitudinal rails 12 face towards the interior of the frame 2. These longitudinal rails 12 are bonded to the longitudinal profiles 5 by soldering or welding. The U-shaped longitudinal rails 12 are designed so that the inlay 3 can be suspended within them with some play and can be moved along the longitudinal direction of the longitudinal rails 12.

[0089] Each of the transverse side profiles 6 is attached to a U-shaped transverse rail 14 (Fig. A1c), with the openings of the U-shaped transverse rails 14 pointing towards the center of the frame 2. The U-shaped transverse rails 14 serve to receive the transverse edges of the inlay 3. The U-shaped transverse rails 14 each have an upper tab 16 and a lower tab 19, with a profile rail 23 formed on the free edge of the lower tab 19. This profile rail 23 extends downwards from the lower tab 19 to the level of the lower narrow side wall 7 of the frame 2, then angles outwards towards the adjacent transverse side profile 6 and extends to the transverse side profile 6. From there, the profile is angled upwards again, forming a support tab 30 which rests against the inwardly facing broad side wall 8 of the transverse side profile 6. Fig. 1c).

[0090] The cross rail 14 has some recesses in the area of ​​the outer edge of the upper tab 16 ( Fig. 2b) in the area of ​​the recess in the lower tab 19, a through-opening is formed through which a screw bolt 32 extends, with which the cross rail 14 is screwed into corresponding threaded bores in the upper narrow side wall 7 of the transverse side profile 6 and thus fastened to the frame 2. The corresponding screw connections are detachable, so that the cross rails 14 are detachably fastened to the frame 2. By loosening the screw connections, an inlay 3 enclosed by the longitudinal rails 12 and cross rails 14 can be detached such that it is freely movable in the longitudinal rails 12 and can be separated from the frame 2 and replaced by another inlay 3.

[0091] In the present embodiment, the inlay 3 is a perforated sheet ( Fig. 2e, Fig. 18) formed, wherein the holes are arranged in a regular grid. In the present embodiment, three adjacent holes are arranged at the vertices of each equilateral triangle, the centers of the holes forming the vertices of the equilateral triangle. The vertices of this equilateral triangle are spaced 3.5 mm apart. The holes have a diameter of 2 mm.

[0092] This regular grid can also be described as having holes arranged evenly in rows, with adjacent rows offset from each other by half a hole spacing.

[0093] Of course, perforated sheets of different dimensions, and in particular perforated sheets with a different hole pattern, can also be used. Inlays 3 can also be used, which are formed from expanded metal 78 or from a rigid or flexible mesh 79, as explained in more detail below with reference to the second embodiment.

[0094] The cross rail 14 with the profile rail 23, on which the support tab 30 is formed, can be easily positioned correctly on the transverse side profile 6 by placing the support tab 30 against the transverse side profile 6 and then screwed in place. The profiles 23 with their support tab 30 also ensure that the U-shaped rail of the cross rail 14 does not tilt during use and is reliably always aligned in the same way.

[0095] In the present embodiment, the inlay 3 is made of a thin sheet metal with a thickness of 1.15 mm. By providing the compartment 4, it is even possible to use thinner sheets. The thinner the sheet metal, the lower the heat capacity of the inlay 3.

[0096] The frame 2 and the cross braces 9 and longitudinal braces 10 of the compartment 4 are made of stainless steel, in particular chromium-nickel steel. The U-shaped longitudinal rails 12 and the U-shaped transverse rails 14 are also made of the same material as the frame 2, since in particular the longitudinal rails 12 are bonded to the longitudinal braces 10 and longitudinal side profiles 5 of the frame 2, and different materials between the longitudinal rails 12 and transverse rails 14 on the one hand and the frame profiles 5 and 6 on the other hand would lead to stresses in the frame 2.

[0097] Inlay 3 is made of aluminum or an aluminum alloy.

[0098] The slim design of the frame 2 allows for significant weight savings compared to conventional baking trays 1 for industrial applications. The compartment 4 serves two functions. Firstly, it stiffens the frame 2, as the cross braces 9 and longitudinal braces 10 of the compartment 4 are firmly (here, by bonding) connected to the frame 2. Secondly, the compartment 4 supports the inlay 3 at regular intervals on its underside. This allows the inlay 3 to be made very thin, resulting in considerable weight savings. Thus, the compartment 4 serves both to stiffen the baking tray 1 and to reduce weight, since the support provided by the compartment 4 allows for the use of a very thin and therefore lightweight inlay 3.Likewise, the compartment 4 stiffens the frame 2, which allows for the use of a significantly slimmer frame 2 compared to conventional industrial baking trays 1, resulting in considerable weight savings.

[0099] With a baking tray 1 measuring approximately 2 m x 0.8 m, a weight of about 4-5 kg ​​can be saved compared to conventional baking trays 1, i.e., the weight in this embodiment can be reduced from about 16 kg to 11 to 12 kg.

[0100] Furthermore, the low weight of the baking tray 1 significantly reduces its heat capacity. The weight of a conventional baking tray 1 is approximately 40% greater than that of the baking tray 1 according to the first embodiment. This results in energy savings of at least approximately 15% in industrial baking systems, since a significantly smaller heat capacity needs to be heated, and consequently, less heat is lost from the baking machine when a baking tray 1 is removed.

[0101] Due to its low weight, the baking tray 1 according to the invention is also much easier for one person to handle.

[0102] The inlays 3 can be replaced as often as desired. The inlays 3 typically have a non-stick coating (especially PTFE) which wears down over time. The lifespan of the frame 2 with its integrated compartment 4 is not limited. Thanks to the floating mounting, any number of inlays 3 can be replaced on the frame 2. Furthermore, the floating mounting prevents any tension between the inlay 3 and the frame 2, even if the baking tray 1 is subject to significant temperature fluctuations and the inlay 3 and the other parts of the baking tray 1 are made of different materials.

[0103] A second embodiment of a baking tray 1 for industrially operated baking plants is described below using the following as an example: Fig. 3a to 6f explained.

[0104] The baking tray 1 is formed from an outer frame 2, an inlay 3 and an inner frame 34, into which a compartment 4 is integrated ( Fig. 3a).

[0105] The outer frame ( Fig. 4a to 4g) is rectangular in plan view, formed from two longitudinal side profiles 5 and two transverse side profiles 6, which are connected to each other at the corners by means of a stacking corner 35.

[0106] The longitudinal side profiles 5 and transverse side profiles 6 each have a rectangular hollow profile in cross-section with two opposing broad side walls 8 and two opposing narrow side walls 7 ( Fig. 4d). In the present embodiment, the broad side wall 8 has a width or height of 30 mm and the narrow side wall 7 has a width or height of 10 mm. The profiles of the longitudinal side profiles 5 and the transverse side profiles 6 can also be dimensioned differently. Preferably, the width of the broad side wall 8 is n times that of the narrow side wall 7, where n is at least 1.5 or at least 2, and preferably at least 2.5.

[0107] The stacking corner 35 is a solid, roughly cuboid-shaped body ( Fig. 4e-4g), which has a bottom side 36 and a top side 37. On the top side 37, an upwardly projecting tenon 38 is formed approximately in the middle at the stacking corner 35. The tenon 38 has a conically tapered shape. On the bottom side 36, a recess 39 is formed, which is suitable for receiving a tenon 38 of another stacking corner 35.

[0108] The longitudinal side profiles 5 and transverse side profiles 6 are connected to the stacking corners 35 by means of a material-bonded connection, such as a welded or soldered joint, so that together they form the outer frame 2. The outer frame 2 is made of stainless steel, in particular chromium-nickel steel. Such steel possesses high mechanical strength and stiffness, as well as high abrasion resistance, which is important for use in industrial ovens to minimize abrasion within the oven.

[0109] Threaded bores 40 are formed at regular intervals on the inner walls of the longitudinal side profiles 5 and transverse side profiles 6, into which screw bolts 41 can be inserted to connect the inner frame 34 and the inlay 3 to the outer frame 2.

[0110] The inlay 3 of the present embodiment is made of a perforated sheet 43 ( Fig. 5a) and strips 44 clamped to the edge of the perforated sheet 43. The strips 44 are each formed from a strip-shaped sheet metal, which has a strip section 45 that is somewhat perpendicular to the perforated sheet 43 and a flanged section 46 formed thereon. The flanged section 46 is flanged around the respective edge region of the perforated sheet 43, so that the strips 44 are firmly connected to the perforated sheet 43.

[0111] The perforated sheet 43, which is approximately rectangular in plan view, thus has four strips 44 that extend approximately over the entire longitudinal and transverse edges of the perforated sheet 43, with only the corner areas 47 of the inlay 3 being free of the strips 44 ( Fig. 5a-5c).

[0112] In the strip section 45, elongated holes 53 are formed, extending longitudinally along the strips 44 and arranged such that they align with the threaded bores 40 in the assembled baking tray 1, allowing the screw bolts 41 to extend through them. The provision of the elongated holes 53 allows for a certain amount of play between the inlay 3 and the outer frame 2.

[0113] Both the perforated sheet 43 and the strips 44 are made of aluminium or an aluminium alloy.

[0114] In the present embodiment, the perforated sheet 43 has a thickness of 1.15 mm.

[0115] In the present embodiment, the inner frame 34 is formed from a strip-shaped aluminum sheet, which is folded outwards at its upper lower edge, thus forming a lower and upper flanged edge 48a and 48b. The flanged edges 48a and 48b serve to stiffen the inner frame 34, and by providing these flanged edges 48a and 48b, sharp edges on the inner frame 34 are avoided. The inner frame 34 is manufactured in one piece from the aluminum strip, which is bent accordingly in the corner areas 47, and the end sections of the strip are joined together by means of a material-bonded connection, in particular a welded or soldered joint.

[0116] On the longitudinal sides of the inner frame 34, elongated holes 49 are formed, which extend in the longitudinal direction of the longitudinal sides and serve to fasten the inner frame 34 together with the inlay 3 to the outer frame 2.

[0117] Support profiles 9 are attached to the inner frame 34 ( Fig. 6a). The support profiles 9 ( Fig. 6c and Fig. 6e) are extruded profiles with a tubular section 50 and two diametrically opposed webs 51, 52 on the tubular sections 50. The upper web 51 is wider than the lower web 52. The support profile 9 can be fastened to the inner frame 34 with a threaded bolt 41 such that the bolt 41 extends through a hole (not shown) in the inner frame 34 and is screwed into the tubular section 50 of the support profile 9. The screw connections between the inner frame 34 and the support profiles 9 result in the inner frame 34 and the support profiles 9 forming a kind of rigid truss structure. In the present embodiment, six support profiles 9 are provided in the inner frame 34 (see Fig. 6a). The support profiles 9 extend parallel to the transverse sides of the inner frame 34. It is, of course, also possible to provide a different number of support profiles 9. It is advantageous to provide at least three, and in particular at least four or at least five, support profiles 9. The more support profiles 9 are attached to the inner frame 34, the stiffer it is, but the heavier the entire baking tray 1 becomes.

[0118] The support profiles 9 have incisions 54 at regular intervals on their upper webs 51, each extending from the upper edge of the support profile 9 to the tubular section 50 of the support profile 9.

[0119] In the present embodiment, the cutouts 54 have a depth of 8 mm. Strip-shaped support plates 10 are inserted into the cutouts 54, extending parallel to the longitudinal sides 57 of the inner frame 34 over the entire length of the inner frame 34. The support plates 10 ( Fig. 6f) In the present embodiment, they have a height of 8 mm, so that their upper edge is flush with the upper edge of the upper webs 24 of the support profiles 9. In the present embodiment, five support plates 10 are provided, which are arranged at uniform intervals along the support profiles 9 or along the transverse sides of the inner frame 34. A different number of support plates 10 can also be provided in the frame 2 of the invention. It is advantageous to provide at least three, in particular at least four, preferably at least five support plates 10.

[0120] The support profiles 9, together with the support plates 10, form the bay 4, which extends within the inner area of ​​the inner frame 34. The support profiles 9 thus represent the transverse braces 9 and the support plates 10 the longitudinal braces 10 of the bay 4.

[0121] The inner frame 34 is attached to the outer frame 2 by means of the screw bolts 41, the screw bolts 41 extending through the elongated holes 49 of the inner frame 34 and the elongated holes 53 of the strips 44 of the inlay 3 in order to engage in the threaded bores 40 of the outer frame 2.

[0122] The inner frame 34, the inlay 3, and the outer frame 2 are detachably connected to one another by means of these screw connections. The elongated holes 49, 53 allow a certain tolerance in the arrangement of the inner frame 34 and the inlay 3 in the plane of the baking tray 1 with respect to the outer frame 2.

[0123] These screw connections allow an inlay 3 to be exchanged with the outer frame 2 and the inner frame 34 as often as desired.

[0124] Only the outer frame 2 is made of steel. This ensures both high strength and high abrasion resistance during use in an industrial oven. The other components (with the exception of the screw bolts) are made of aluminum or an aluminum alloy. Aluminum or aluminum alloy has high thermal conductivity, allowing heat to be distributed quickly across the baking tray 1, and is also a lightweight material, making the baking tray 1 significantly lighter than conventional baking trays 1.

[0125] The provision of the compartment 4 formed by the support profiles 9 and the support plates 10 allows the use of a thin-walled perforated sheet 43, since the perforated sheet 43 is supported at regular intervals by the compartment 4. In the present embodiment, the longitudinal distance between the support profiles 9 is less than 40 cm and the transverse distance between the support plates 10 is less than 15 cm. This minimizes the risk of deflection of such a supported perforated sheet 43, even if the perforated sheet 43 is very thin-walled.

[0126] A thin-walled perforated sheet also has the advantage over conventional thicker perforated sheets that it is not only lighter, but also has a very low heat capacity and quickly assumes the ambient temperature, thus heating the baked goods faster than is the case on a thick perforated sheet.

[0127] The perforated sheets 43 are coated. Typically, a non-stick layer, especially made of PTFE, is applied. This coating wears off over time. The perforated sheets 43 therefore need to be replaced. By using thin-walled aluminum sheets, material consumption is reduced accordingly. Replacing the perforated sheets 43 is therefore more cost-effective than replacing conventional thick-walled perforated sheets.

[0128] A third embodiment of a baking tray 1 for industrially operated baking plants is described below using the following as an example: Fig. Sections 7a to 10b are explained.

[0129] The baking tray 1 of the third embodiment is similar to the baking tray 1 of the second embodiment, consisting of an outer frame 2 and an inlay 3, which is why identical parts are provided with the same reference numerals and, unless otherwise stated, the explanations relating to the second embodiment apply equally to the third embodiment for the corresponding parts.

[0130] The outer frame ( Fig. 7a to Fig. 8i) is rectangular in plan view, formed from two longitudinal side profiles 5 and two transverse side profiles 6, which are connected to each other at the corners by means of a stacking corner 35. The longitudinal side profiles 5, the transverse side profiles 6 and the stacking corners 35 are designed in the same way as in the second embodiment.

[0131] Unlike the second embodiment, the walls of the longitudinal side profiles 5 are provided with threaded holes (not shown) into which screw bolts are inserted to connect the longitudinal side profiles 5 to a support plate 91 ( Fig. 8f, Fig. 8g), which extends between the longitudinal side profiles 5 and runs parallel to the transverse side profiles 6. The support plate 91 has a bottom wall 92 and a side wall 93, the side wall 93 being formed at a right angle to the edge of the bottom wall 92. The support plate 91 has an end wall 94 at each of its ends, which is oriented perpendicular to the bottom wall 92 and side wall 93. The end wall 94 extends upwards a short distance beyond the side wall 93. In the present embodiment, the side wall 93 has a height h of 7 mm ( Fig. 8f), wherein the end wall 94 projects 8 mm beyond the upper edge of the side wall 93. A through-hole is formed approximately in the center of each end wall 94, through which a screw bolt is inserted to fasten the respective support plate 91.

[0132] In the present embodiment, two support plates 91 are attached to the outer frame 2. The support plates 91 are arranged such that the upper edge of the side wall 93 is spaced downwards from the top surface or the upper narrow side walls 7 of the longitudinal side profiles 5.

[0133] More than two support plates 91 may also be provided.

[0134] The outer frame 2 has two retaining plates 25 ( Fig. 8h, Fig. 8i) which are each arranged adjacent to or adjacent to the transverse side profiles 6 ( Fig. 7a or 8a). The retaining plates 25 have a retaining wall 31, a bottom wall 33, and a fixing wall 55. The three walls 31, 33, 55 form an approximately L-shaped cross-section (see Fig. 8i), wherein both the retaining walls 31 project vertically upwards at one edge of the base wall 33 and the fixing wall 55 project vertically upwards at the other edge of the base wall 33. The fixing wall 55 serves to fix the retaining plate 25 to the transverse side profile 6. This is done, for example, by means of a material-bonded connection (soldering or welding). The retaining wall 31 is spaced from the inwardly directed broad side wall 8 of the transverse side profile 6 by the width of the base wall 33 and runs parallel to this inwardly directed broad side wall 8.

[0135] The retaining plate 25 also provides a support surface for paternoster lifts, which grip the baking trays from below in the area of ​​the end faces.

[0136] The retaining wall 31 has vertically downward-extending notches 56 at regular intervals along its upper, free edge. In the present embodiment, the notches 56 have a depth of 8 mm and a width of 1-2 mm and open at the upper edge of the retaining wall 31, so that longitudinal struts 57 of a compartment 4 can be inserted into the notches 56 from above. The compartment 4 is formed from the longitudinal struts 57 and transverse struts 58, wherein the longitudinal struts 57 and the transverse struts 58 each consist of steel strips which, in the present embodiment, have a width of 8 mm. The longitudinal sides 57 and transverse struts 58 each have notches at regular intervals so that they can be inserted into one another at the intersection points of the compartment 4.The notches in the longitudinal struts 57 extend from the upper edge of the longitudinal strut 57 to approximately the middle of the longitudinal strut 57, and the notches in the transverse struts 58 extend from the lower edge to approximately the middle of the transverse struts 58, so that the transverse struts 58 are supported from below by the longitudinal struts 57.

[0137] The compartment 4 can thus be inserted into the notches 56 of the retaining walls 31 and, due to gravity, holds securely in the retaining plates 25, even if the inlay 3 has not yet been inserted into the baking tray 1.

[0138] On the outer frame 2, several spring-loaded pressure pieces 59 are located in the area of ​​the longitudinal side profiles 5 ( Fig. 7a, 8b-8e) provided.

[0139] Such a spring-loaded pressure piece 59 is formed from a blind-hole-shaped housing 60, which has an outwardly projecting collar 61 at its free edge and in which a compression spring 62 is arranged, which pushes a ball 63 outwards. A circumferential, inwardly projecting projection 81 at the free edge of the housing 60 prevents the ball 63 from completely exiting the housing 60. Fig. 8e).

[0140] Several of these spring-loaded pressure pieces 59 are arranged on the inwardly facing broad side walls 8 of the longitudinal side profiles 5 such that the spring-loaded ball 63 protrudes slightly inwards on the broad side wall 8 of the longitudinal side profile 5.

[0141] In the third embodiment, the inlay 3, like in the second embodiment, has a perforated sheet 43 and is provided with clamped strips 44 at the edge of the perforated sheet 43 ( Fig. 9a to Fig. 9c). The design of inlay 3 of this third embodiment corresponds to inlay 3 of the second embodiment, therefore reference is made to the corresponding explanations for the second embodiment.

[0142] The inlay 3 of the third embodiment differs from the inlay 3 of the second embodiment in that the strips 44 have recesses 50 along the longitudinal edge of the inlay 3, so that the strips 44 are interrupted. In the area of ​​the recesses 50, the support plates 91 with their end walls 94 are in the fully assembled baking tray 1 ( Fig. 7a) ordered.

[0143] Furthermore, elongated holes 64 are formed in the strips 44 along the longitudinal edges of the inlay 3. The elongated holes 64 are each positioned corresponding to the spring-loaded pressure pieces 59 of the outer frame 2, so that when the inlay 3 is inserted, the strips 44 bear against the inner sides of the longitudinal side profiles 5 and transverse side profiles 6, with the strips 44 being locked to the longitudinal side profiles 5 with the elongated holes 64 on the spring-loaded pressure pieces 59 by the balls 63 engaging in one of the elongated holes 64.

[0144] The connection between the inlay 3 and the outer frame 2 is therefore a snap-fit ​​connection that can be easily released.

[0145] When the inlay 3 is fixed in the outer frame 2, then the longitudinal struts 57 and transverse struts 58 of the compartment 4 are also secured against falling out.

[0146] The baking tray 1 according to the third embodiment has a simple structure in which the inlay 3 and the outer frame 2 can be repeatedly and releasably fastened together by means of the snap connection, wherein the inlay 3 is supported by the compartment 4, so that the inlay 3 can have a very thin perforated sheet 43 and in addition the outer frame 2 is slim and therefore light yet stable.

[0147] With a baking tray 1 measuring approximately 2 m x 0.8 m, a weight of about 8 kg can be achieved in this third embodiment, which is almost half the weight compared to conventional baking trays 1.

[0148] A fourth embodiment of a baking tray 1 for industrially operated baking plants is described below based on the Fig. Sections 11a to 17b are explained.

[0149] The baking tray 1 of the fourth embodiment is similar to the baking tray 1 of the third embodiment, consisting of an outer frame 2 and a separate inlay 3, which is why identical parts are provided with the same reference numerals, and, unless otherwise stated, the explanations relating to the third embodiment for the corresponding parts apply equally to the corresponding parts of the fourth embodiment.

[0150] The outer frame ( Fig. 11a to 11d, Fig. 13a and Fig. 13b) is rectangular in plan view, consisting of two longitudinal side profiles 5 and two transverse side profiles 6, which are connected to each other at the corners by means of a stacking corner 35. The longitudinal side profiles 5, the transverse side profiles 6 and the stacking corners 35 are designed in the same way as in the second and third embodiments.

[0151] Unlike the third embodiment, the longitudinal side profiles 5 have bores (not shown) in their walls, each serving to receive a stiffening rod 65. The stiffening rods 65 are, for example, rods with a circular cross-section, which are either loosely inserted into the corresponding bores or fixed to the longitudinal side profiles 5 by means of a material-bonded connection (welding or brazing). In the present embodiment, the outer frame 2 has two stiffening rods 65 that run parallel to the transverse side profiles 6. Of course, several stiffening rods 65 can also be provided.

[0152] If the stiffening rods 65 are rigidly connected to the longitudinal side profiles 5, they can also absorb tensile forces, thereby stiffening the outer frame 2 as a whole. The stiffening rods 65 can also be attached to the longitudinal side profiles 5 by means other than a bonded connection, for example, by a screw connection. The stiffening rods 65 of the present embodiment are solid bodies. A stiffening tube can also be provided instead of such a solid body. The stiffening rods 65 are preferably made of the same material as the rest of the outer frame 2, namely chromium-nickel steel.

[0153] The outer frame 2 has two retaining plates 28 ( Fig. 17a, Fig. 17b) which are arranged adjacent to or adjacent to the transverse side profiles 6 ( Fig. 11a or 13a). The retaining plates 28 are U-shaped in cross-section ( Fig. 17b) formed with a bottom wall 66 and two U-shaped legs 67. The retaining plate 28 is attached to the adjacent transverse side profile 6 by one of the two U-shaped legs 67 such that the opening of the U-shaped retaining plate 28 points upwards. The retaining plate 28 has rectangular recesses 68 at each of its ends, in which the stacking corners 35 of the assembled outer frame 2 fit.

[0154] In the present embodiment, the retaining plates 28 are attached to the transverse side profiles 6 by a metallurgical bond (welding and brazing). However, they can also be attached by any other fastener, such as a screw connection. The retaining plates 28 are made of chromium-nickel steel.

[0155] The compartment 4 ( Fig. 14a to 14d, 15a, 15b, 16) is formed in the present embodiment from a wire mesh with longitudinal wires 69 and transverse wires 70.

[0156] The cross wires 70 ( Fig. 15a, Fig. 15b) have a length such that they extend between the longitudinal side profiles 5. At their ends, the transverse wires 70 are angled downwards ( Fig. 15a) and bent accordingly to form screw eyes 71. The screw eyes 71 form an isosceles triangle with rounded corners ( Fig. 15b).

[0157] A notch 42 is formed at regular intervals on each of the transverse wires 70, each of which serves to receive a longitudinal wire 69. The notch 42 is formed by a section of the transverse wire 70 that is curved downwards relative to the rest of the transverse wire 70.

[0158] The longitudinal wires ( Fig. 16) are essentially straight wires of such length that they can extend between the transverse side profiles 6. At their ends, the longitudinal wires 69 are each bent downwards a short distance, forming a vertical support section 72.

[0159] In the fourth embodiment, the inlay 3, like in the second and third embodiments, has a perforated sheet 43 and is provided with strips 44 clamped to the edge of the perforated sheet 43.

[0160] The inlay 3 of the fourth embodiment differs from the inlay 3 of the second and third embodiments in that the strips 44 along the longitudinal edge of the inlay 3 have elongated holes 73, which are arranged to correspond to the positions of corresponding threaded bores 74 on the inwardly facing broad side wall 8 of the longitudinal side profiles 5. Furthermore, the strips 44 along the longitudinal edge of the inlay 3 are formed with recesses 89 that are open downwards in order to accommodate the stiffening rods 65 when the baking tray 1 is assembled.

[0161] The baking tray 1 is assembled in such a way that the inlay 3 and the compartment 4 are inserted into the outer frame 2 and secured with screw bolts 76 ( Fig. 11b) The screw eyes 71 of the transverse wires 70 are attached to the longitudinal side profiles 5. The strips 44, with their elongated holes 73, are located along the longitudinal edge of the inlay 3 in the area between each screw eye 71 of the transverse wire 70 and a threaded bore 74 of the longitudinal side profile 5, so that the screw bolt 76 fastens not only the transverse wire 70 but also the inlay 3 to the outer frame 2. The longitudinal wires 69 rest in the notches 42 of the transverse wires 70 and are supported by their vertical support sections 72 against the retaining plate 28.

[0162] The compartment 4 formed from the transverse wires 70 and longitudinal wires 69 supports the perforated sheet 43 of the inlay 3 from below, just as in the other embodiments.

[0163] The baking tray 1 of the fourth embodiment is lighter than conventional industrial baking trays 1 due to its slim outer frame 2 and the support of the perforated sheet 43 from below by the compartment 4. Furthermore, the screw connections with which both the inlay 3 and the compartment 4 are attached to the outer frame 2 can be loosened and re-tightened using standard tools, so that the inlay 3 can be replaced by any participant in the production chain of baked goods after the coating of the perforated sheet 43 has worn away.

[0164] The above-described embodiments of a baking tray 1 each have a perforated sheet as an inlay 3 ( Fig. 18) on.

[0165] The inlay 3 of the exemplary embodiments can also be an expanded metal 78 instead of a perforated sheet 77 ( Fig. 19). Both the perforated sheet 77 and the expanded metal 78 are made of aluminum or an aluminum alloy. They each have a non-stick coating on their upper surface, which can be made of PTFE, for example. The advantage of expanded metal 78 over a perforated sheet is the large proportion of openings to the total surface area. This allows the baked goods to be heated more quickly and effectively from below, thus improving the quality of the baked product.

[0166] The inlay 3 can also have a grid 79 instead of a perforated sheet or expanded metal 78.

[0167] A self-rigid grid 79 can, for example, be formed from metal wires, in particular aluminum wires. The individual wires can cross over each other alternately, like in a woven fabric. However, the wires can also be joined at the contact points by means of a soldered or welded connection.

[0168] The grid 79 can also be formed from a flexible grid 79, such as a fabric made of temperature-stable filaments. The individual filaments of the fabric can be glass fibers. The glass fibers are preferably coated or impregnated with a plastic. Such a filament can have a single elongated fiber. Instead of glass fibers, other temperature-stable fibers, in particular mineral fibers such as silicon carbide fibers, can also be used.

[0169] A filament of the fabric can also comprise multiple fibers. These fibers can run parallel to each other within the filament (roving). Alternatively, several fibers can be interwoven (yarn). The individual or multiple fibers are preferably embedded in a temperature-stable polymer, such as PTFE, silicone, or epoxy.

[0170] An inlay 3, especially if it is made of such a fabric, has an extremely low weight and extremely low heat capacity compared to conventional inlays 3 of baking trays 1. Both of these properties are advantageous for the efficiency of the baking tray 1 during operation.

[0171] If the baking tray 1 is a flexible grid 79, then the inlay 3 can have four slats 44, as they are found, for example, in the Fig. 5a-5c or 9a to 9c or Fig. 12a, Fig. Figure 12b shows that these strips 44 clamp the edge of the mesh 79 with their crimped sections 46. These strips 44 can, for example, be attached to a longitudinal side profile 5 or transverse side profile 6 of the frame 2 by means of a screw connection, whereby when the screws are tightened, the strips 44 are drawn towards the respective profiles 5, 6, thus tensioning the flexible mesh 79. In this embodiment, the screw connection not only allows for easy replacement of the inlay 3 on the frame 2, but also serves to tension the flexible mesh 79 in the baking tray 1, so that despite the very light and flexible design of the mesh 79, a stable support for the baked goods is provided.

[0172] In an alternative embodiment, the grid 79 can be enclosed in a circumferential inner frame 34 ( Fig. 21a to 21c) are inserted and clamped herewith. This inner frame 34 has an approximately circular cross-section, which is formed with a slot 80 on the inwardly facing side. At the lower edge of the slot 80, the profile forms an upwardly pointing curved projection 81, which transitions inside the profile into a support area 82, which in the present embodiment is approximately flat.

[0173] The grid 79 is inserted into the circumferential slot 80 of the inner frame 34 with its edge section, and then the upper section of the profile is pressed downwards so that a free edge 83 of the upper section presses down on the grid 79 from above, pulling it downwards and inwards along the projection 81 into the inner frame 34. This tensions the grid 79 and wedges the upper section of the profile against the projection 81, thus fixing the grid 79 under tension within the inner frame 34.

[0174] The inner frame 34 can then be fixed to the outer frame 2 to form a baking tray 1. Snap-fit ​​and / or screw connections can be provided for this purpose. Additional strips 44 with corresponding snap-fit ​​elements or holes for screw connections can be provided on the inner frame 34 for this purpose.

[0175] Such an inner frame 34 with clamped grid 79 can also form a back-off baking tray 1 without an additional outer frame 2, in which the requirements for strength are lower than for a baking tray 1 for industrial baking lines.

[0176] Within the scope of the invention, various other embodiments of the clamping devices for clamping a flexible grid 79 are also possible. For example, in Fig.Figure 22 shows an inner frame 34, which is formed from four separate units, each along one of the longitudinal sides and each along one of the transverse sides of the frame, each comprising a lower and upper profile element 84, 85, between which the grid 79 can be clamped. The lower profile element 84 has a corresponding slot-shaped recess 89, into which a corresponding clamping projection 90 of the upper profile element 85 engages, so that the grid 79 is fixed between the lower and upper profile elements 84, 85.

[0177] The outer frame 2 is also formed in two parts, with a lower frame part 86 and an upper frame part 87. The lower and upper frame parts 86, 87 each have tensioning ramps 88, so that the inner frame 34 inserted into the outer frame 2 is pulled outwards and the grid 79 is tensioned when the lower and upper frame parts 86, 87 are compressed. It should be noted that the lower and upper frame parts 86, 87 of the outer frame 2 are each formed as a single, continuous piece, whereas the lower and upper profile elements 84, 85 each extend only along one longitudinal side or transverse side of the inlay 3 or the grid 79, respectively, so that the individual sections of the profile elements 84, 85 can be pulled outwards independently of one another to tension the grid 79.

[0178] Some embodiments feature strips 44 which are part of the inlay 3 and are attached to the perforated sheet, expanded metal, or mesh by clamps. When using a perforated sheet, it is also possible to form the strips in one piece from the perforated sheet and bend the corresponding sections downwards at right angles. These strips preferably do not have the holes of the perforated sheet, but are formed with all other recesses and holes, like the strips 44 described above. They differ only in their direct connection to the rest of the perforated sheet. The same applies to expanded metal, provided the expanded metal has edge areas without through-openings that are suitable as strips. Reference symbol list 1 baking tray 2 frames 3 Inlay 4 compartments 5 longitudinal side profiles 6 cross-section profiles 7 narrow side walls 8 broadside wall 9 Support profile / cross brace 10 Support plate / longitudinal strut 11 notches 12 longitudinal rails 14 U-shaped cross rails 16 upper flap 19 lower flap 23 Profile rail 24 upper bridges 25 retaining plates 28 retaining plates 30 support bracket 31 retaining wall 32 screw bolts 33 Floor wall 34 inner frames 35 Stacking Corner 36 bottom side 37 Ceiling side 38 cones 39 Exclusion 40 threaded holes 41 screw bolts 42 notches 43 Perforated sheet metal 44 strips 45 Groin section 46 Flanged section 47 corner areas 48a lower flange edge 48b upper flange edge 49 elongated holes 50 tubular section 51 footbridges 52 lower bridge 53 Slotted hole 54 cuts 55 Fixing wall 56 cuts 57 longitudinal struts 58 cross braces 59 spring-loaded pressure pieces 60 blind-shaped housings 61 collars 62 Compression spring 63 balls 64 elongated holes 65 stiffening rod 66 Floor wall 67 U-shaped thighs 68 cutouts 69 Wire mesh with longitudinal wires 70 cross wires 71 screw eyes 42 notches 72 vertical support section 73 elongated holes 74 threaded holes 76 screw bolts 77 perforated sheet metal 78 Expanded metal 79 Grid 80 slots 81 lead 82 print run 83 free edge 84 Profile element 85 upper profile element 86 lower frame part 87 upper frame part 88 slant angles 89 slotted recess 90 clamping projection 91 Support plate 92 Floor wall 93 side wall 94 Front wall QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 0710441 B1

[0002] EP 2 394 514 A1

[0005] WO 2023 / 037351 A1

[0006] EP 2708129 B1

[0007] WO 2015 / 044588 A1

[0008] US 2022 / 0322682 A1

[0009] US 2017 / 0318820 A1

[0010] WO 2005 / 092007 A2

[0011] EP 2 014 171 B1

[0012] WO 2005 / 3430 A1

[0013] WO 2009 / 123451 A1

[0014] EP 2826373 A1

[0015] FR 2097608 A5

[0016] DE 20 2013 004 320 U1

[0017] DE 20 2010 007 826 U1

[0018]

Claims

[1] Baking tray for industrially operated baking plants comprising a frame and an inlay, wherein the baking tray is flat and the inlay made of a perforated sheet of aluminium or aluminium alloy with a thickness of not more than 1.3 mm, in particular not more than 1.15 mm, or from expanded metal made of aluminium or an aluminium alloy, or is formed from a grid network arranged under tension, and The frame is formed from a rectangular-section hollow profile made of steel or a high-temperature plastic, which has two broad side walls and two narrow side walls, wherein the broad side walls are wider than the narrow side walls and the narrow side walls are arranged approximately parallel to the inlay and the broad side walls approximately perpendicular to the inlay. [2] Bachblech according to claim 1, characterized bythat the grid is formed from a metal wire or non-metallic filaments, wherein the filaments are preferably formed from aligned and impregnated fibers. [3] Baking tray according to claim 1 or 2, characterized by that the baking tray has a width of at least 0.6 m and / or a length of at least 0.8 m. [4] Baking tray according to any one of claims 1 to 3, characterized by that the broad side wall of the frame has a width of at least 20 mm, in particular at least 25 mm or at least 30 mm and / or the narrow side wall of the frame has a width of at least 5 mm and in particular at least 10 mm and preferably not more than 20 mm and in particular not more than 15 mm. [5] Baking tray according to any one of claims 1 to 4, characterized by that the frame is made from a single, continuous metal tube. [6] Baking tray according to any one of claims 1 to 5, characterized bythat the frame has a compartment consisting of at least one transverse and / or at least one longitudinal strut to support the inlay. [7] Baking tray for industrially operated baking plants, in particular according to one of claims 1 to 5, comprising a frame and an inlay, characterized by that the frame has a compartment consisting of several transverse and / or longitudinal struts to support the inlay. [8] Baking tray according to claim 6 or 7, characterized by that the transverse and / or longitudinal struts are each formed from a metal or plastic strut with a specific profile, whereby the profiles can be an I-profile, L-profile, U-profile or a round profile. [9] Baking tray according to any one of claims 6 to 8, characterized by that the transverse and longitudinal struts are connected or interlocked at their intersection points. [10] Baking tray for industrially operated baking plants, in particular according to one of claims 1 to 9, comprising a frame and an inlay, characterized by that the inlay is floating on the frame. [11] Baking tray according to claim 10, characterized by that the frame has at least two opposing struts with U-shaped rails, the openings of which are aligned towards each other, so that the inlay rests in the U-shaped rails at its edges. [12] Baking tray according to claim 11, characterized by , that a detachable fixing element is arranged on the frame, with which the inlay, which is slidably mounted in the U-shaped rails, can be fixed. [13] Baking tray for industrially operated baking plants, in particular according to one of claims 1 to 12, comprising a frame and an inlay, characterized by, that the inlay has a surrounding plug-in frame which is detachably connected to the frame, wherein the plug-in frame and the frame are designed to be pluggable into each other. [14] Baking tray according to claim 13, characterized by that the inlay is attached to the plug-in frame by means of a clamping connection, snap connection or screw connection. [15] Baking tray according to claim 13 or 14, characterized by , that the plug-in frame has locking means which cooperate with corresponding counter-locking means provided on the frame to fix the inner frame to the frame. [16] Baking tray according to claim 15, characterized by , that the locking means and counter-locking means comprise spring-loaded locking projections and corresponding locking recesses, in particular elongated holes extending in the longitudinal direction of the respective struts of the frame or inner frame.

Images