EP0994309B1 - Withdrawal device for food support in a baking oven - Google Patents

Description

The invention relates to a telescopic pull-out device for at least one food support in a cooking space of a cooking oven.

It is known in household ovens to form guideways in the enamelled side walls of the cooking space as a holder for the food supports that can be introduced into different levels of the cooking space, such as baking trays, racks, fat collecting pans, into which the food supports can be inserted with their lateral edges and pulled out again. In an embodiment of such an oven known from DE 35 44 582 C2, a sliding pad is applied between the food supports and the guideways in the oven on one of the two opposite sliding and supporting areas, which is coated with a plastic coating, for example made of polytetrafluoroethylene, or a running profile made of aluminum or Stainless steel is formed and slides on an opposite enamelled area. This prevents damage to the enamel layer when the food carriers are pushed in or out of the cooking space.

In other known household ovens are used for mounting the food carrier telescopic pull-out used to the Food carriers run as smoothly as possible and individually towards the front to be able to pull out of the cooking space. Every telescopic pull-out consists of two by means of so-called ball cages slidably guided rails, one of the Rails is mounted on the respective cooking space wall. In The ball cages of the telescopic extensions must be on the one hand To prevent squeaking noises when moving the food support and on the other hand to achieve smooth sliding, a lubricant, e.g. a special, temperature-resistant Fat, can be provided. Those in the cooking space of the household oven telescopic extensions are by the vapors that occur in the oven when baking and roasting and fat splashes over time due to buildup, however significantly contaminated. Then such telescopic pull-outs removed from the cooking space and with the help of special Means cleaned what z. B. also in a dishwasher can be done by the usually extremely aggressive cleaning agents Lubricant for the telescopic rails from the telescopic pull-outs washed out and thus their silent smoothness canceled. Furthermore, they fulfill such Telescopic rails used lubricants only up to a certain temperature range in the cooking space their purpose satisfactory. For domestic stoves with one pyrolytic self-cleaning, through which all impurities in the cooking space at very high temperatures 500 ° C are carbonized, are the known telescopic rails no longer suitable.

The invention is therefore based on the object easy-care telescopic pull-out device for a food rack to create a cooking oven.

The solution to this problem according to the invention is the features of claim 1.

The telescopic pull-out device is for at least one Food carriers are provided in a cooking space of a cooking oven and formed and comprises rails (elongated support elements), on or on which at least one food support can be placed or can be fastened, and guides (guide elements), in which the rails in plain bearings with sliding along Sliding surfaces are guided, the rails in their guides can be at least partially pulled out of the cooking space are. Include at least on their sliding surfaces the rails, the guides or both the rails as also the guides each one at the operating temperatures the oven's temperature-resistant sliding material (Material with good sliding properties, sliding material), so that a low sliding friction, i.e. a low coefficient of sliding friction, between the sliding on each other Sliding surfaces of rails and corresponding guides is reached.

The coefficient of sliding friction between two bodies is determined the frictional force that counteracts the movement when the glide both bodies together with their surfaces or friction, and therefore referred to as sliding friction becomes. The sliding friction force is proportional to Normal force that presses the two bodies together with the coefficient of sliding friction as a proportionality factor. The coefficient of sliding friction depends on the type and Surface condition of the materials of the two bodies, so here the rail and the leadership. The coefficient of sliding friction can be easily determined experimentally as the tangent of the angle of an inclined plane at which the one body on top of the other is uniform (with constant Speed) because then by the The force of movement exerted by gravity is precisely the force of friction compensated.

The telescopic pull-out device for food carriers is based on the invention on a, preferably linear, plain bearing and is therefore due to their without cage ball bearings or roll-out construction easy to manufacture and to wait. The special sliding material has the advantage that the telescopic extension device also during Operation of the oven is smooth and comparatively has a long service life.

Advantageous further developments and refinements of the subject of the invention are in the dependent claims specified.

In a first embodiment of the telescopic pull-out device the rails and / or the guides are essentially made entirely of the sliding material, for example as a coherent (one-piece) molded body.

The rails and / or the guides do not have to be completely consist of a sliding material. Especially at high Costs or a non-self-supporting property of the Sliding material, it can be more advantageous only to the Sliding surfaces of the rails and / or the guides the sliding material provide, preferably by applying a Layer (coating) of the sliding material.

Furthermore, prefabricated, massive moldings can also be made from the sliding material used on a generally base body not made of the sliding material the rails and / or the guides arranged stationary are and their surfaces at least partially Form sliding surfaces of the slide bearings of the telescopic pull-out system. This variant has the advantage that the special Shaping for the plain bearing done by the sliding body can, while standard shapes for the rails and / or guides can be used.

The telescopic pull-out device can be used for food carriers in several cooking chamber levels can be further developed by in corresponding Levels for one food support each two rails and associated guides are provided.

The sliding surfaces of the rails and / or the guides can in one embodiment over the entire extension direction running management area, i.e. the area in which the rails and the associated guides sliding against each other are displaceable, or in a second embodiment only over part of the management area run (otherwise then unsupported).

The guides preferably limit movement of the associated ones Rails on at least one side, so that the Rails with as little tolerance as possible linear in the guides are movable and do not slide outwards or inwards can (lateral fixation of the rails in the Guides).

The sliding material can support the sliding effect be self-lubricating.

In a special development are the sliding material and any other materials of the telescopic pull-out device even at temperatures of at least about 500 ° C temperature resistant. These special material properties allow that the telescopic pull-out device also at during pyrolytic self-cleaning of the oven pyrolysis temperatures in the cooking space in the cooking space can remain and even by pyrolysis of the Residue is cleaned. It is also advantageous here surface hardening through a particularly hard sliding material.

In a particularly advantageous embodiment, the Sliding material not only thermally, but also opposite a soapy water, especially one in a dishwasher Usually used soapy water, chemically resistant. This enables the telescopic pull-out device to be cleaned from sticking during cooking Grease residues and other organic residues Wash in soapy water, especially in a dishwasher.

• Polymer-Kunststoffe, insbesondere mit eingelagerten Metallteilchen (z.B. Körner, Kugeln),
• keramische Werkstoffe,
• korrosionsfeste Metalle, insbesondere temperatur- und korrosionsfeste Stähle wie beispielsweise INOX-Stähle oder graphitierte Metalle
• Metallverbindungen, insbesondere Metallcarbide oder Metallnitride, vorzugsweise Titannitrid
• Graphitwerkstoffe und Carbide
• Siliciumverbindungen, insbesondere Siliciumcarbid

Preferred materials for the sliding material are alone or in combination

• Polymer plastics, especially with embedded metal particles (e.g. grains, spheres),
• ceramic materials,
• Corrosion-resistant metals, in particular temperature and corrosion-resistant steels such as INOX steels or graphitized metals
• Metal compounds, in particular metal carbides or metal nitrides, preferably titanium nitride
• Graphite materials and carbides
• Silicon compounds, especially silicon carbide

The coefficient of sliding friction between each other sliding surfaces (sliding surfaces) of rails and associated Guides is generally set below 0.5, can in particular be below 0.4 and preferably even below 0.2.

It is also beneficial in addition to good lubricity in addition, there is little adhesion between rails and guides adjust so that even at the beginning of pulling out No excessive forces are required to spill over of sauces or liquids in the food can lead an edge of the food support. The static friction between two bodies is the frictional force that counteracts the movement force when the two bodies are pressed together under a normal force and relative are at peace with each other. The static friction is proportional to normal force with the coefficient of static friction as a proportionality factor. Stiction is practical always greater than the sliding friction. A particularly low one In most cases, static friction is caused by material combinations already achieved, if the sliding friction is chosen small. It can now be the coefficient of static friction between the sliding surfaces of rails and guides even below 1.0, especially below 0.7 and should preferably be chosen below 0.4. The coefficient of static friction can be easily determined experimentally as the tangent of the angle of an inclined plane at which the one body is just beginning to slide on the other, because then the force of motion exerted by gravity is just equal to the frictional force.

The telescopic pull-out device is installed in a cooking oven with a cooking space preferably on the wall of the cooking space attached releasably or non-releasably. With a detachable attachment is the telescopic pull-out device from the cooking space removable, for example for cleaning or in front of a Pyrolysis if the materials are at pyrolysis temperatures are not heat-resistant.

The invention is described below with reference to the drawing illustrated preferred embodiments described in more detail.

Fig. 1

eine perspektivische Ansicht eines Garofens mit aufgeklappter Garofentür und eingesetzter Auszugsvorrichtung mit nach vorne herausgezogenen Gargutträgern;

Fig. 2 und 3

einen Schnitt durch zwei unterschiedlich ausgestalteten Teleskopauszüge einer Auszugsvorrichtung.

Einander entsprechende Teile sind in den Fig. 1 bis 3 mit denselben Bezugszeichen versehen.Each shows in a schematic representation:

Fig. 1

a perspective view of a cooking oven with the oven door open and the pull-out device used with the food carriers pulled out towards the front;

2 and 3

a section through two differently designed telescopic pull-outs of a pull-out device.

Corresponding parts are provided with the same reference numerals in FIGS. 1 to 3.

1 is in a cooking space (oven space) 1 Cooking oven (baking and roasting oven) 2 a pull-out device for in or out of the cooking space 1 in different levels and food carriers that can be retracted or extended independently of each other 5, 5 'arranged. The pull-out device includes for each a food support 5, 5 'two on opposite Side walls 3 arranged in a horizontal cooking space level elongated (linear) guides 4 for associated Rails 6.

In each of the guides 4 that are stationary relative to the cooking space 1 one of the rails 6 is slidably mounted and axially (linear) essentially parallel to the associated oven level and slidable to the associated side wall 3. On the the two rails 6 the associated food support 5.5 'is free can be placed on the front end of the rails 6 arranged stops 41 and possibly by additional Limits such as pens and corresponding ones Holes fixed relative to the rails 6. In a Modification not shown, the food support 5.5 ' also permanently connected to the associated rails 6 his. With these measures, each food support 5.5 'is individual from the cooking space 1 by one through the pull-out path the rails 6 dependent path relative to the guides 4 pulled out. In Fig. 1, both food carriers are shown 5 and 5 'each with the oven door 20 open Pulled a little way out of the cooking space 1.

The guides 4 are on two perpendicular support rails 40 attached, which in turn on the associated side wall 3 are attached. The carrier rails are preferably 40 releasably attached to the side walls 3, for example hooked into this and / or with a light releasable screw connection attached and thereby together with the guides 4 and the rails 6 located therein Removable from the cooking space 1, especially for cleaning or customer service purposes. Instead of the carrier rails shown 40 can also be known lattice-shaped Carrier elements can be provided, which can also be inserted directly of food carriers in at least one level without Allow telescopic extension.

The concrete shape of rails 6 and associated guides 4 can be selected in many ways. Prefers is an at least largely closed embodiment, which is commonly referred to as a telescopic extension and where the movable rail (telescopic rail) from the Leadership largely shielded from external influences is. The guide is then also generally rail-shaped educated.

2 and 3 show two different embodiments a pair of rail 6 and associated guide 4 of such telescopic pull-out devices. Both the rail 6 as well as the guide 4 comprise profile parts, preferably from a corrosion-free or with a corrosion-resistant Coating such as chrome Sheet steel, with an essentially U-shaped cross section. The open sides of the U-shaped profile parts are facing each other and the two U-legs (here: the upper and lower wall) of the guide 4 come outside of each facing U-leg (here: the upper and lower Wall) of the rail 6 to lie.

2, the rail 6 a cross-sectionally U-shaped profile part as base body 60 and one or more sliding bodies 8 on the outer sides of the two U-legs 7 of the base body 60, with sliding body 8 and base body 60 by a suitable temperature-resistant Connection technology are interconnected, for example by gluing, welding, soldering or the like. Everyone The sliding body 8 of the rail 6 is provided with a high temperature resistant the operating temperatures in the cooking space 1 non-liquefying or volatilizing, i.e. dimensionally stable, and on its surface, good sliding material educated. Furthermore, each sliding body 8 is the Rail 6 in corresponding engagement with the respective Guide 4 brought and extends in the extension direction (Management direction) over the entire management area the rail 6 or at least part of it. in the Sliding body 8 is one running in its guiding direction Fixing 9 in the manner of a longitudinal groove (longitudinal groove) for lateral centering (lateral fixation perpendicular to the Extension direction) of the movable rail 6 with respect to the in these engaging guide legs 10 of the U-shaped Leadership 4 trained. The respective guide leg 10 the U-shaped guide 4 is for this purpose with a Profile of the fixation 9 adapted, in particular V or U-shaped, Forming or deformation (bulge) 11 provided. The facing surfaces of the formation 11 of the guide 4 and the corresponding fixation 9 in Sliding bodies 8 of the rail 6 form rubbing against each other Sliding surfaces 12 of the rail 6 and guide 4 according to Art of a linear sliding bearing formed oven-telescopic extension.

In another embodiment of the pull-out device according to Fig. 3 are the sliding surfaces sliding on each other 12 of rail 6 and guide 4 each with a coating from a high temperature resistant and preferably hard Provide sliding material (hard material sliding coating). A such a sliding coating can, for. B. from titanium nitride or materials with similar properties. This measure has the great advantage that a equipped telescopic pull-out device especially for domestic stoves with a pyrolytic Self-cleaning of the cooking space 1 is very suitable and not removed from the cooking space 1 before pyrolysis must be cleaned, but even cleaned during pyrolysis can be. The surface hardening also prevents one Deformation of the parts of the telescopic pull-out at high pyrolysis temperatures. Appropriate higher if accepted The entire rail 6 and / or can of course also cost Guide 4 consist of such a hard sliding material. In the embodiment of FIG. 3, the guide legs 10 of the guide 4 two outwardly deformed U or V-shaped Deformations or Deformations (Bulges) 13 on, in each of which a corresponding, also after externally directed shape 14 of the rail 6 engages. The two mutually facing surfaces of the formations 13 and 14 form the sliding surfaces 12 of the slide bearing of the telescopic extension.

In all embodiments, of course, can be kinetic Reversal the guide 4 retractable and the Rail 6 to be stationary to cooking space 1. Moreover, in generally also stops or the like as movement limits to limit the relative movement between leadership 4 and rail 6 are provided.

All sliding and up to the come as sliding materials maximum operating temperatures of the oven from 240 ° C to 300 ° C during cooking and possibly 500 ° C during pyrolysis resistant and solid materials in question. Preferably the materials should also be alkali resistant, too enable cleaning in dishwashers.

• Metalle und metallische Sinterwerkstoffe, die durch Kohlenstoffzufuhr oberflächengehärtet (graphitiert) sein können, vorzugsweise rostfreie, temperaturfeste Stähle (Edelstähle) wie INOX-Stahl,
• Metallverbindungen, insbesondere Metallcarbide wie beispielsweise Titancarbid oder Wolframcarbid oder Metallnitride wie beispielsweise Titannitrid,
• Siliciumcarbid oder Siliciumnitrid in gesinterter oder kristalliner Form,
• Graphitwerkstoffe, beispielsweise ein unter dem Handelsnamen Dotherm bekannter Werkstoff,
• keramische Werkstoffe,
• hochtemperaturfeste polymerisierte Kunststoffe (Polymere oder Polymerverbindungen), insbesondere mit eingelagerten Metallpulver oder Bronzekugeln oder Graphitpartikeln, wie beispielsweise
  Polyimide (PI), insbesondere Polymethacrylimid (PMI) oder das aus Pyrazintetracarbonsäureanhydrid und Diaminothiodiazol hergestellt PPDA,
  Polyoxymethylen (Polyacetal, POM), das einen besonders geringen Gleitreibungskoeffizient aufweist,
  Polyamide,
  Polyfluorethylene, insbesondere Polytetrafluorethylen, und andere fluorierte oder anders halogenierte Kohlenwasserstoffe (Halogenanteil erhöht Temperaturfestigkeit), PTFE, insbesondere mit Molybdänsulfid und/oder Bronzekugeln oder
  Polyphenylen (PPH).

Suitable sliding materials are in particular:

• Metals and metallic sintered materials, which can be surface hardened (graphitized) due to the supply of carbon, preferably stainless, temperature-resistant steels (stainless steels) such as INOX steel,
• Metal compounds, in particular metal carbides such as titanium carbide or tungsten carbide or metal nitrides such as titanium nitride,
• Silicon carbide or silicon nitride in sintered or crystalline form,
• Graphite materials, for example a material known under the trade name Dotherm,
• ceramic materials,
• high-temperature-resistant polymerized plastics (polymers or polymer compounds), in particular with embedded metal powder or bronze balls or graphite particles, such as
  Polyimides (PI), in particular polymethacrylimide (PMI) or the PPDA produced from pyrazine tetracarboxylic anhydride and diaminothiodiazole,
  Polyoxymethylene (polyacetal, POM), which has a particularly low sliding friction coefficient,
  polyamides,
  Polyfluorethylene, in particular polytetrafluoroethylene, and other fluorinated or otherwise halogenated hydrocarbons (halogen content increases temperature resistance), PTFE, in particular with molybdenum sulfide and / or bronze balls or
  Polyphenylene (PPH).

Some of these materials are only for a coating or only for a massive execution as a self-supporting body prefers.

The surface of the sliding material can also more smooth by polishing or other mechanical processing be made.

Claims (15)

1. Telescopically extending device for at least one cooking-product support in a cooking chamber of an oven, having rails which are guided slidingly in guides, are at least partly removable from the cooking chamber, and on which at least one cooking-product support can be laid or fixed, wherein the rails (6) and/or the guides (4) have at least on their slide faces a respective sliding material composed of a metal nitride, preferably titanium nitride, which is temperature-resistant at the operating temperatures of the oven.
2. Telescopically extending device according to claim 1, wherein the rails and/or the guides are formed substantially entirely from the sliding material.
3. Telescopically extending device according to claim 1, wherein the rails and/or the guides are provided on their slide faces with a coating of the sliding material.
4. Telescopically extending device according to claim 1, wherein the rails and/or the guides respectively have base bodies (60) and prefabricated sliding bodies, which are mounted on the base bodies, consist of the sliding material, and on which the slide faces are formed.
5. Telescopically extending device according to one of the preceding claims, having two rails respectively and associated guides in different planes of the cooking chamber for a respective cooking-product support.
6. Telescopically extending device according to one of the preceding claims, wherein the sliding material comprises at least as a component a polymer plastics material, in particular having embedded metal particles.
7. Telescopically extending device according to one of the preceding claims, wherein the sliding material comprises a ceramic material at least as a component.
8. Telescopically extending device according to one of the preceding claims, wherein the sliding material comprises, at least as a component, a graphited metal, in particular a metal carbide, or a graphite material or silicon compound, in particular silicon carbide.
9. Telescopically extending device according to one of the preceding claims, wherein the sliding material is chemically resistant to a rinsing lye, in particular a rinsing lye used in a dishwasher.
10. Telescopically extending device according to one of the preceding claims, wherein the sliding material is still temperature-resistant at pyrolysis temperatures of the oven of at least about 500°C, and preferably also has a high degree of hardness.
11. Telescopically extending device according to one of the preceding claims, wherein the rails and/or the guides have slide faces extending over the entire guide region extending in the extension direction or only over part thereof.
12. Telescopically extending device according to one of the preceding claims, wherein the guides fix the rails at least in a direction extending perpendicular to the extension direction, preferably in at least two opposite directions.
13. Telescopically extending device according to one of the preceding claims, wherein the sliding friction coefficient between the slide faces sliding over one another of the rails and associated guides is set at less than 0.5, in particular less than 0.4 and preferably less than 0.2.
14. Telescopically extending device according to one of the preceding claims, wherein the adhesion friction coefficient between the slide faces of rails and guides is less than 1.0, in particular less than 0.7 and preferably less than 0.4.
15. Oven having a cooking chamber and a telescopically extending device fixed preferably detachably and removably to the wall of the cooking chamber, according to one of the preceding claims.

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