EP1589290B1 - Extraction system for a household appliance - Google Patents

Abstract

The pull-out system has at least one element (25) which is protected by a cover element (23,27) from impurities and has a lubricant layer (22) such as inorganic solid grease or graphite. The lubricant layer is preferably chemically resistant. The lubricant layer has a binding agent which holds the lubricant against the roller body cage. The roller body cage is formed as a stop to restrict movement of the extension element.

Description

The invention relates to an extension system for a household appliance, in particular cooking appliance, which has at least one extract element which is protected by a cover from contamination.

Out DE 38 15 440 a generic telescopic insertion device is known, which is designed as a telescopic extension with a stationary inner rail, a rollable middle rail and a rollable outer rail for the food support. At the middle rail two rollers are each mounted by bolts. In the bolt grooves are formed, which serve to accommodate high-temperature-resistant grease or lubricating paste. When the telescopic insertion device is pushed together, the outer rail forms a covering element for the middle rail.

Out EP 0 994 309 A2 a generic extension device is known, which partially has a cooking chamber pull-out rails. These are slidably guided in stationary guides. The rails and / or the guides are provided at least on their sliding surfaces with a sliding material.

Out DE 102 11 470 A1 a generic pull-out system is known which has a stationary inner rail, a movable intermediate rail and a movable outer rail. The rails are provided with an easy-to-clean PTFE-based coating. Depending on the accessibility of the rails or extract elements for food and / or the user different coating qualities are provided. For example, areas which point downwards can be provided with a lower coating quality in terms of cleanability and / or abrasion resistance than areas facing upwards, which are exposed directly to product spills.

Out DE 199 49 239 A1 is a pull-out device, in particular telescopic extension device, known, are guided in the rails by means of ball bearings or roller bearings on stationary guides. The balls of the ball bearings or the Rolls of the roller bearings consist at least on their surface of a self-lubricating material.

Out DE 100 54 954 A1 a telescopic extension device for food support in the cooking chamber of home ovens is known, wherein the movable in different backroom levels Gargutträger be pulled out using slides in ball bearings or roller bearings sliding telescopic rails from the oven. In order to maintain the lubricity of the ball or roller bearings even after cleaning in a dishwasher or pyrolysis, the balls or rollers of a self-lubricating, chemically and thermally stable material.

Out DE 103 30 348 A1 is a Gargutträgersystem for an oven with two on the side walls of the baking muff mountable slide carriers known, wherein in at least one level of the oven, preferably in several levels, rail members for a trained with an outer rail, an inner rail and optionally one or more central rails telescopic rail fixed or detachable are mounted.

The object of the invention is to provide a drawer system for a household appliance, which permanently has good running or sliding properties.

The object of the invention is achieved with a household appliance having the features of patent claim 1. According to the characterizing part of claim 1, the extractor element protected by the cover element has a lubricant layer. The lubricant layer of the extract element is largely protected by the cover element from contamination. The lubricant layer comprises a binder that holds the lubricant to a rail or to a roller body cage. The binder causes an improved connection of the lubricant to the rail surface. In contrast, such a connection does not exist if the lubricant only finds support in a roughened rail surface. A lubricant layer with uniform layer thickness and uniform surface properties is achieved in that the binder is a paint. This can be sprayed for example on the rail, resulting in a uniform layer thickness.

For example, a retaining rail and / or a pull-out rail of the extension system form the cover. The cover member may define a cavity in which the coated with the lubricant layer extract element is arranged. It is advisable that the lubricant layer comprises an inorganic solid lubricant. Although such a lubricant layer has excellent lubricating properties, it is difficult to clean here. This is due to the physical properties of inorganic solid lubricants. The poor cleanability plays only a minor role, since the cover largely protects the movable drawer element from contamination.

Preferably, of the moving pull-out elements of the pull-out system, only a first rail may have the lubricant layer. In contrast, at least one second rail may be coated with a second layer or uncoated. According to the invention it has been recognized that it is sufficient for a sufficient lubrication of the entire extension system to provide only one of the rails with a lubricant layer. Lubricant particles rubbed off from the lubricant layer can also reach running or sliding surfaces in the pull-out system according to the invention which are not in contact with a lubricant layer. This is sufficient in order to maintain a smooth running of the extraction system.

Furthermore, different surface properties can result in differently coated drawer elements or rails. As a result, the running or sliding behavior of the extension system can be significantly increased. The running or sliding behavior improves in particular when the rails are coated with layers of different surface hardness. In view of a favorable production, it is preferred if at least one of the rails is uncoated, i. has a metallic surface.

By means of the movable extension element, a good distribution of the lubricant in the extension system is achieved. In a drawer system consisting of a stationary support rail and a movable drawer rail, it is therefore sufficient if the movable drawer rail is coated with the lubricant layer. The stationary By contrast, the retaining rail can be coated with another layer or be uncoated.

In the event that an intermediate rail is mounted between the movable pull-out rail and the stationary holding rail, it is sufficient according to the invention if only one of the three rails is coated with the lubricant layer. It is particularly preferred if, as the movable extension element, the intermediate rail is coated with the lubricant layer. In this case, the intermediate rail can supply both the pull-out rail and the holding rail with approximately the same amount of lubricant. In this case, manufacturing technology advantageously can be dispensed with a coating of the retaining rail and / or the extension rail. Alternatively, the outer pull-out rail and / or the stationary inner holding rail may be provided with another, approximately corrosion-resistant layer.

It is particularly preferred if the lubricant is an inorganic solid lubricant. Such a lubricant, in contrast to many other lubricants, such as liquid lubricants of oil or grease, even at high temperatures physiologically harmless.

It is advantageous if the lubricant is chemically resistant, in particular alkali-resistant, to enable cleaning in a dishwasher. In this case, the extraction system can also be exposed to chemically aggressive media, for example alkalis in a dishwashing machine.

Inorganic solid lubricants are particularly easy to detach from a layer structure. Distributing the inorganic solid lubricant to pullout elements that are not coated with the solid lubricant is therefore particularly easy. Squeaking noises or a stiffness of the extension system are therefore reliably prevented.
According to the invention it may be advantageous if the lubricant is resistant to high temperatures. For this purpose, all lubricants come into question, which are up to maximum cooking temperatures of up to 300 ° C and optionally up to 500 ° to 600 ° C in the pyrolysis resistant. It is particularly preferred if graphite is used as the solid lubricant. Graphite is even at very high temperatures can be used as well as chemically resistant and also cost-effective. Furthermore, molybdenum disulfide can be used as the solid lubricant. In this case, however, it may become problematic at very high temperatures because of the generation of S ₂ . If the manufacturing costs are only of secondary importance, as a solid lubricant and boron nitride is conceivable that is resistant and physiologically harmless in all temperature ranges. The same applies to tungsten disulfide.

The paint applied to the rail can be burned into the rail together with the lubricant. Advantageously, the lubricant is suspended in the paint. By firing permanently reliable lubrication properties of the rail can be achieved, even if the telescopic extension is exposed to chemically aggressive media or high temperatures.

In order to adjust the abrasion resistance of the rail coating or its layer quality to the requirements, combinations of the abovementioned solid lubricants made of graphite, molybdenum disulfide (MoS ₂ ), boron nitride or tungsten disulfide are also conceivable.

Compared to a plain bearing, with a roller bearing in the extension system an improved pull-out behavior can be achieved. In contrast to a sliding bearing, no frictional force is generated between the movable pull-out elements, but instead roll the movable pull-out elements against one another via rolling elements. As a result, in a drawer system with plain bearing significantly less lubricant is required. It is therefore also possible to use a lubricant layer with lower quality requirements.

According to the invention, the lubrication of the extraction system can be achieved via a lubricant layer provided only on the intermediate rail. Other drawer elements in the extension system, such as rails, rolling elements or Wälzkörperkäfige must therefore take no lubricating function. The rolling elements and / or their Wälzkörperkäfige can therefore be specially designed as limit stops. The mechanical loads occurring in this case could not, for example, be resisted by carbon-based rolling element cages (so-called PEEK cages).

From a manufacturing point of view, it is preferred if the movable extraction element is completely coated with the lubricant. Compared to a partial coating of the extract element thus the coating process can be significantly simplified.

Plays the production cost for applying the lubricant layer on the rail or the pullout element only a minor role, it is conceivable to apply several lubricant layers with different properties. In this case, a lowermost layer layer may have a large proportion of binders and correspondingly less solid lubricant. As a result, an abrasion-resistant mounting of the lubricant is secured to the rail. On the other hand, an uppermost layer can have little binder and, for that, a high proportion of solid lubricant. This increases the lubricity of the rail.

In addition, the lubricant-containing layer may contain further fillers, such as ceramic, to adjust its layer quality or abrasion resistance.

According to a further embodiment, the extension system may be removably mounted in the cooking appliance. In this case, on the one hand, a simple cleaning of the pull-out system outside of the cooking appliance is achieved. On the other hand, for example, in a pyrolysis operation in the cooking appliance, the extraction system can be removed so as not to expose it to high temperatures in pyrolysis operation.

Figur 1

ein Auszugssystem in einem Gargerät;

Figur 2

in einer Schnittdarstellung das Auszugssystem des Gargeräts; und

Figur 3

einen Kugelkäfig des Auszugssystems.

Hereinafter, an embodiment of the invention with reference to the accompanying figures will be described. Show it:

FIG. 1

an extension system in a cooking appliance;

FIG. 2

in a sectional view of the extension system of the cooking appliance; and

FIG. 3

a ball cage of the extension system.

In the FIG. 1 a cooking appliance is shown with a cooking appliance muffle 1, which limits a cooking space. The cooking appliance has a hinged door 3 for closing a front side Muffle opening 5 on. In the FIG. 1 the swing door 3 is shown in an open state. On opposite side walls 9 of the cooking appliance muffle 1 are corresponding lateral guide rods 11 and a pull-out system, consisting of two opposite telescopic extensions 13, supported. The telescopic extensions 13 are removably supported in a top of four horizontal Garraumebenen. In the underlying three Garraumebenen each of the corresponding guide rods 11 are removably supported. On the two corresponding lowermost guide rods 11, a baking sheet 13 is supported, which is partially pushed out of the cooking appliance muffle 1. The guide rods 11 are muffelfrontseitig each inserted in a bearing bush 15. This is mounted in a mounting opening of the muffle side wall 9. The telescopic extensions 13 are formed with a holding plate 14 which is mounted in each case in an annular groove 16 of the bearing bush 15. In the area of a muffle rear wall 17, the guide rods 11 and the telescopic extensions 13 are each mounted in a mounting opening 19. Both the guide rods 11 and the telescopic extensions 13 are tool-free by a user from the muffle 1 to solve.

In the present case, the extension system 13 is designed as a telescopic extension. The telescopic extension 13 is according to the FIG. 2 in one in the FIG. 1 shown viewing direction I shown in cross section. The telescopic extension 13 has a lower holding rail 23, which is held on the holding plate 14 fixed to the muffle side wall 9. Both the retaining plate 14 and the bearing bush 15 are in the FIG. 2 shown with dashed lines. In addition to the stationary support rail 23, the telescopic extension 13 consists of a movable intermediate rail 25 and a likewise movable extension rail 27. The intermediate rail 25 is mounted on balls 29 between the pull-out rail 27 and the stationary support rail 23.

The configuration of the rails 23, 25, 27 is not limited to the present embodiment. Thus, the retaining rail 23 may also be formed like a round rod 11. On the support rail 23, the pull-out rail can be guided sliding or mounted on other rolling elements. The design of the pull-out rail 27 is not limited to the present embodiment. Rather, the pull-out rail 27 may also be designed as a slide, a runner or another pull-out element. Between the extension element 27 and the support rail 23 can also be dispensed with the arrangement of the intermediate rail 25.

The support rail 23 and the extension rail 27 are made according to the FIG. 2 from mutually identically formed U-profile parts of an uncoated sheet steel. The two rails 23, 27 are arranged facing each other with their open sides. They define a substantially closed cavity 31, in which the intermediate rail 25 is arranged. This means that at least in the retracted state of the telescopic extension 13, the intermediate rail 25 is almost completely enclosed by the pull-out rail 27 and the support rail 23. Splashes of grease, dirt or the like are therefore kept away from the balls 29 and from the intermediate rail 25.

In order to allow a smooth pulling and pushing together of the extension system, the intermediate rail 25 is coated with a lubricant layer 33. The lubricant layer 33 is in the FIG. 2 shown in exaggerated layer thickness. The layer thickness is realistically in a range between 10 and 20 microns. In contrast to the intermediate rail 33, both the balls 29 and the support rail 23 and the pull-out rail 27 are not coated with the lubricant layer 33, but uncoated. As a result, the balls 29 run on the one hand on the lubricant layer 33 of the intermediate rail 25 and on the other hand on the uncoated running surfaces of the support rail 23 and the pull-out rail 27. The surface properties of the metal surface of the balls 29, the support rail 23 and the pull-out rail 27 on the one hand and the lubricant layer 33 on the other hand are different , Due to these different surface properties results in a particularly good rolling behavior of the balls 29 and thus good running properties of the extension system.

Alternatively, the holding rail 23 and / or the pull-out rail 27 may be coated with a second layer, as shown in the FIG. 2 is indicated by the reference numeral 34 with a dashed line. The two different layers 33 and 34 have different surface properties. In particular, the rolling behavior of the ball 29 can be improved with a different surface hardness. The second layer 34 may be formed as a corrosion resistant layer, for example.

In the present case, the lubricant layer 33 comprises particles of an inorganic solid lubricant, such as graphite. To produce the lubricant layer 33, a powder of the inorganic solid lubricant is first suspended in a lacquer solution and then the intermediate rail 25 is subsequently coated. In a further step, the paint solution is baked in the intermediate rail 25. This results in an extremely high mechanical abrasion resistance of the coating 33 and a good chemical resistance to aggressive media, such as detergents. In addition to this cost-effective coating method, other methods, such as a PVD coating (Physical Vapor Deposition) or a CVD coating (Chemical Vapor Deposition) for producing the lubricant layer 33 are conceivable.

The lubricant layer 33 of the intermediate rail 25 is sufficient to introduce enough lubricant between the balls 29 and the pull-out rail 27 or the holding rail 23. The in the FIG. 2 illustrated U-shaped rails 23, 27 are particularly well suited to protect the intermediate rail 33 from contamination. In the in the FIG. 2 it is sufficient to adapt the lubricant layer 33 only with regard to its lubricating properties. In this case, the cleaning ability of the lubricant layer 33 is of subordinate importance. The protection against contamination of the lubricant layer 33 is taken over by the U-shaped retaining rail 23 or the pull-out rail 27. These act at least in the inserted state as cover with respect to the intermediate rail 25. An contamination of the intermediate rail 25 is therefore largely reduced.

Only such a protection of the intermediate rail 25 from contamination therefore makes it possible to suitably coat the intermediate rail 25 with the inorganic solid lubricant layer 33. Namely, such a layer is very difficult to clean compared with, for example, a PTFE-based layer.

According to the FIG. 2 the balls 29 are arranged in two opposing ball cages 37. The balls 29 are rotatably supported in the ball cages 37. One of the ball cages 37 in the FIG. 3 shown. The ball cage 37 consists of a thin sheet steel, which is formed into an angular part with three trapezoidally arranged in profile sides 39. In each of the sides 39 recesses 41 are cut out. The Recesses 41 are arranged on each side 39 in two consecutive rows. The two rows are spaced apart by a central portion 43 of the ball cage 37. Each recess 41 is partially bounded by an angled embossing edge 45 which holds the ball 29 in the recess 41.

The in the Figures 2 and 3 shown ball cages 37 are additionally coated with the lubricant layer 33. In the FIG. 2 the applied on the ball cage 37 lubricant layer 33 is indicated by dashed line. In the FIG. 3 is the applied on the ball cage 37 lubricant layer 33 indicated in hatching. As a result, due to the rotation of the balls 29 on the angled embossing edge 45, a slight lubricant abrasion can be generated. The abrasion is distributed by the adjusting movement of the telescopic extension 13 along the running surfaces of the rails 25, 23, 27. As a result, the pull-out behavior of the extension system is permanently improved. Furthermore, squeaking noises or sluggishness in the operation of the telescopic extension are effectively reduced. The application of the lubricant layer 33 on the ball cage 37 takes place here as the application of the lubricant layer 33 to the respective rail.

The ball cages 37 are freely movable between the rails 23, 25, 27 in the longitudinal direction. The end faces 47 of each ball cage 37 are used in the in the FIG. 2 shown telescopic extension 13 as stops that limit a longitudinal movement of the rails 23, 25, 27. The telescopic extension 13 can therefore be pulled apart until the end faces 47 of the ball cage 37 come into contact with corresponding rail stops, not shown.

Claims (23)

1. Pull-out system for a domestic appliance, particularly cooking appliance, which has at least one pull-out element (25) which is protected by a cover element (23, 27) from contaminations, characterised in that the pull-out element (25) has a lubricant layer (33), which comprises a binder which keeps the lubricant at a rail or a roller body cage (37), and that the binder is a lacquer.
2. Pull-out system according to claim 1, characterised in that the lubricant layer (33) comprises an inorganic solid lubricant.
3. Pull-out system according to claim 1 or 2, characterised in that the lubricant layer (33) comprises graphite.
4. Pull-out system according to any one of the preceding claims, characterised in that the lubricant layer (33) comprises molybdenum disulfide.
5. Pull-out system according to any one of the preceding claims, characterised in that the lubricant layer (33) comprises boron nitride.
6. Pull-out system according to any one of the preceding claims, characterised in that the lubricant layer (33) comprises tungsten disulfide.
7. Pull-out system according to any one of the preceding claims, characterised in that the lubricant layer (33) is formed to be chemically resistant.
8. Pull-out system according to any one of the preceding claims, characterised in that the lubricant layer (33) is formed to be resistant to high temperature.
9. Pull-out system according to any one of the preceding claims, characterised in that the lacquer with the lubricant is baked into the pull-out element (25)
10. Pull-out system according to any one of the preceding claims, characterised in that the pull-out element (25) is mounted in the pull-out system by way of roller bearings (29).
11. Pull-out system according to claim 10, characterised in that the roller bodies (29) are arranged in a roller body cage (37).
12. Pull-out system according to claim 11, characterised in that the roller body cage (37) is constructed as an abutment for limiting movement of the pull-out element (25).
13. Pull-out system according to one of claims 11 and 12, characterised in that the roller body cage (37) is coated with the lubricant layer (33).
14. Pull-out system according to any one of the preceding claims, characterised in that the pull-out element (25) is completed coated with the lubricant layer (33).
15. Pull-out system according to any one of the preceding claims, characterised in that the lubricant layer (33) is formed to be multi-layered at least in part.
16. Pull-out system according to any one of the preceding claims, characterised in that the lubricant layer (33) contains further fillers, particularly of ceramic.
17. Pull-out system according to any one of the preceding claims, characterised in that the pull-out system (13) is withdrawably mounted in the domestic appliance.
18. Pull-out system according to any one of the preceding claims, characterised in that the cover element (23, 27) is a stationary mounting rail (23), at which the pull-out element (25) is mounted, of the pull-out system.
19. Pull-out system according to any one of the preceding claims, characterised in that the cover element (23, 27) is a movable pull-out rail (27), which is mounted on the pull-out element (25).
20. Pull-out system according to claim 19, characterised in that the pull-out element (25) is constructed as an intermediate rail which is mounted between the stationary mounting rail (23) and the movable pull-out rail (27).
21. Pull-out system according to claim 20, characterised in that the mounting rail (23) and/or the pull-out rail (27) encloses or enclose the intermediate rail (25).
22. Pull-out system according to claim 21, characterised in that the mounting rail (23) and/or the pull-out rail (27) bound a cavity (31) in which the intermediate rail (25) is arranged.
23. Domestic appliance with a pull-out system according to any one of the preceding claims.

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