EP0844327A1 - Electric iron - Google Patents

Abstract

In an electric iron manufacturing process, in which an aluminium-silicon alloy block is cast together with the heating element and the ironing surface is provided with an aluminium oxide layer, the low silicon-content aluminium sole is fixed in good thermal contact with the block and the aluminium oxide layer is formed on the outer face of the sole by anodising. Preferably, the aluminium oxide layer is 20-80 mu thick and the sole is fixed to the block by means of a temperature resistant silicone adhesive.

Description

The invention relates to a method for producing an electric iron cast an iron block made of silicon-containing aluminum with a heater is formed and the surface forming the ironing surface as an aluminum oxide layer becomes.

In the brochure "HART-COAT", edition AHC 183, by A.H.C.-Oberflächentechnik München GmbH, 81369-Munich, Eucken-Strasse 4 Application examples on surface protection using anodic oxidation for aluminum materials, in particular a "HART-COAT" coating. According to the brochure, the anodic oxidation results on the surface the aluminum material has a very hard aluminum oxide layer that is wear-resistant, is corrosion-resistant, hard, glides well and can withstand high temperatures. For the application Such oxide layers on aluminum parts should according to the brochure among other things also suitable "iron soles" (5th page of the brochure).

An electric iron of the type mentioned at the outset is already known from EP 217 014 known. This iron has an iron block made of cast aluminum, in which an electric heater is included. The iron sole is as a composite sole integrally formed with the iron block, whereby by means of a Plasma sprayed an aluminum oxide layer sprayed onto the iron block so as to form the soleplate of the iron.

In a preferred embodiment of the invention, the electric iron manufactured by a process in which an iron block made of silicon-containing Aluminum is poured with a heater, and the one that forms the ironing surface Surface is formed as an aluminum oxide layer, a plate-shaped Iron sole made of low-silicon aluminum is attached to the iron block so that both are in good thermal contact, that the aluminum oxide layer on the Outer surface of the soleplate which forms the ironing surface and which is produced Alumina layer is formed by an anodizing process.

In particular, this creates an optically high-quality sole.

In a preferred method of making an iron, the outer surface of the rolled sheet before producing the aluminum oxide layer using a Surface processing operation, such as grinding or polishing, such treated mechanically that there is a roughness depth of Ra less than or equal to 0.1 mm preferably 0.06 mm, and the surface of the rolled sheet by means of a Anodizing process by chemical oxidation in an aluminum oxide layer with a Thickness of 20 to 80 microns, preferably 35 to 45 microns, is converted and after the formation of the aluminum oxide layer its surface by a The polishing process is treated mechanically in such a way that a roughness depth Ra of less than 0.12 Mymeter, preferably 0.06 Mymeter, arises, and then the so manufactured soleplate attached to the iron block by fasteners is, which is not yet provided with an aluminum oxide layer Iron sole by means of a grinding or polishing process particularly simple and can be inexpensively pretreated because the bare aluminum surface is very soft and can therefore be brought to the required roughness depth in the shortest possible time. By the surface roughness is already before this first machining operation Application of the aluminum oxide layer so reduced that after application of the Aluminum oxide layer the roughness of the resulting ironing surface only very much little needs to be reduced by post-processing. This results in significantly shorter polishing times until the desired roughness depth is reached on the very hard ironing surface of the aluminum oxide layer, which leads to a reduction in price Leads soleplate.

But in addition to this advantage, there is also the advantage that in particular not in the specifically higher-loaded edge areas up to the aluminum oxide layer is removed to the bottom. Because straight edges are flat and smooth Surfaces during the polishing process a higher specific contact pressure of the grinding or Exposed to polishing discs or brushes, causing abrasion in these areas Aluminum oxide layer is always higher anyway at constant polishing speed. Around To counteract this disadvantageous phenomenon, one could either use the Reduce the polishing pressure when reaching the corners, which is only very good in practice is difficult to carry out, or you can, as a further development according to the invention shows, rounding the transitions or edges so much that the polishing process specific surface load decreases in these marginal areas.

In a preferred method of making an iron is a method specified, in which the soleplate of the iron by means of a temperature-resistant Silicone glue is glued to the surface of the iron block, and thus is particularly firmly connected to the iron block. At the same time, the Steam outlet holes opposite the edge of those formed in the iron block Steam channels sealed so that the steam only on the Steam outlet holes emerges. Furthermore, the adhesive layer of the silicone adhesive is only so thin that as much heat as possible from the iron block into the soleplate is initiated. A two-component adhesive is used as the adhesive Alumina is added (approx. 70% share). This creates an intimate Connection and good heat conduction between the iron block and the Soleplate.

In a preferred method of making an electric iron at least a portion of the outer surface of the soleplate when anodizing in this way covered that this section after the anodizing process an electrically conductive Free form. This can lead to the formation of electrically conductive vacancies subsequent processing operations can be avoided.

In a preferred embodiment, the electric iron is made with one Silicon-containing cast aluminum block provided, the one has electric heating. A surface is provided which consists of a There is aluminum oxide layer and forms the ironing surface of the iron, one plate-shaped iron soleplate made of low-silicon aluminum on the iron block attached, being in good thermal contact with the latter, the The outer surface of the soleplate is covered with an aluminum oxide layer Forms ironing surface and the aluminum oxide layer is produced by anodizing. For this purpose, a plate-shaped iron soleplate made of a low-silicon aluminum used, which is then attached to the iron block so that it is in good condition There is thermal contact with the iron block. The use of the iron soleplate Low-silicon aluminum enables an optically high-quality, flawless and flawless aluminum oxide layer, through which - after attachment to the iron block and completion to the iron - an electrically operated Iron arises, which many placed on it in terms of its ironing surface Requirements such as corrosion resistance, wear resistance, very good hardness, good gliding behavior, no adhesion problems on the ironing material, good Temperature resistance and high insulation effect etc. fulfilled. By choosing the Material aluminum is a particularly light sandwich construction from Iron block and soleplate.

With the iron according to the invention, not only those mentioned above can be used Achieve benefits, but there is also an ironing surface that is extremely Uniform color coding with a high degree of purity and good surface quality having. An iron soleplate with such a high-quality coating is inexpensive to produce in series and it is also relatively easy to Fasten the iron block. In particular, discoloration occurs on the Iron sole surface hardly at temperature effects and prolonged use on, so that the visual impression of the ironing surface is still after a long time is still positive.

In a preferred embodiment of the electric iron there is Iron soleplate from a rolled sheet. Plated are preferred Rolled sheets made of a wrought aluminum alloy, in particular of the types aluminum-manganese-magnesium (AlMg 4.5 Mn) aluminum-magnesium (AlMg 3), aluminum-copper-magnesium (AlCuMg 1), etc. Such rolled sheets are practically silicon-free, so that an absolutely homogeneous aluminum oxide layer can be produced. The components refining the aluminum not more than 5%, preferably even less than 3% be.

In a preferred embodiment of the electric iron, the surface the soleplate of the iron to a roughness of Ra before producing the aluminum oxide layer less than or equal to 0.1 mymeter, preferably greater than 0.06 mymeter. It according to the invention, the surface of the Flat iron sole, preferably to a roughness depth of less than or equal to 0.1 Mymeter. This high surface quality can be advantageous, for example, by a Achieve grinding or polishing. By pre-polishing or pre-grinding the the soleplate not yet provided with an aluminum oxide layer results in the Advantage that after the manufacture of the soleplate with alumina for obtaining the required final roughness is less removed from the surface produced in this way must be as if it had not been pre-polished or pre-ground. By the Less removal can also make the thickness of the aluminum oxide layer relatively thin can be selected without this hard layer again in the polishing process must be removed to the bottom in order to achieve the desired roughness depth. Man So despite the desired roughness, it still maintains a closed and therefore always corrosion-protected aluminum oxide layer. The removal of aluminum from the iron soleplate not yet coated with an aluminum oxide layer up to a Roughness less than 0.1 mymeter can be carried out extremely quickly in practice because the still uncoated and therefore still very soft aluminum surface Iron sole can be easily smoothed or machined.

In a preferred embodiment of the electric iron, the Alumina layer a thickness of 20 to 80 microns, preferably 35 to 45 Mymeter, so that an ironing surface is reached, which also greater loads withstands no significant damage and is extremely protected against corrosion. The The smallest thickness (20 mm) of the aluminum oxide layer is sufficient for a pretreatment the surface of the soleplate according to claim 3 also for that then removed the surface to a surface roughness of less than 0.1 mm without any locally polished areas appearing.

In a preferred embodiment of the electric iron Iron sole penetrated by steam outlet holes, the edge area at Transition to the outer surface of the soleplate is rounded and the rounding one Radius R greater than or equal to 0.3 mm, preferably 0.5 mm. Thus it is achieved that during the polishing of the surface of the aluminum oxide layer on the specified roughness depth these not entirely in the area of the steam outlet holes is removed, because a specific takes place on the edges during the polishing process much higher removal than on a flat, relatively smooth surface. It is advantageous that the outer edge region of the soleplate has a radius greater than or equal to 0.3 mm, preferably 0.5 mm. Through the two measures, namely, on the one hand, before producing the aluminum oxide layer, the surface of the bare Bring iron soleplate to a predetermined roughness depth, for example by Grinding or polishing, and on the other hand, the transitions on edges are sufficiently round To design, is achieved according to the invention that the Aluminum oxide layer, however, not in the subsequent polishing process on the endangered zones, such as the edges, are worn down to the bottom. On the other hand also leads to less material removal from a very hard aluminum oxide layer at shorter processing times.

In a preferred embodiment of the electric iron, the individual ends Steam outlet holes in recessed in relation to the iron surface Ring steps. But since the ring steps at the transition to the ironing surface are larger Diameter than the diameter of the now recessed Have steam outlet holes, a larger radius can also be selected there. The more rounded edge area prevents that during the polishing process with unchanged polishing speed locally a noteworthy higher removal of the aluminum oxide layer occurs than on the flat areas the ironing surface is the case. If, on the other hand, the edge areas were sharp-edged, it would the aluminum oxide layer can be completely removed.

In a preferred embodiment of the electric iron, there are several Steam outlet holes from a bead recessed in relation to the ironing surface surrounded, and the transition of the bead is both to the steam outlet holes as to Outer surface of the soleplate rounded. In the edge area of the bead from a Radius R greater than or equal to 0.3 mm, preferably 0.5 mm, lead to several Steam outlet holes in a bead so that its in the surface of the soleplate mouth a whole group of steam outlet holes, preferably two to five, surrounds. The outer edge of the bead formed in this way leaves a considerably larger one Curvature as well as a rounded edge area. This advantage in turn enables the choice of larger radii at the edge of the bead, so that here too during the The polishing process of the aluminum oxide layer is gentle on this edge area treated, that is not completely removed.

A particularly scratch and wear-resistant iron sole results in one preferred embodiment of the electric iron when the Aluminum oxide layer has a Vickers hardness HV 0.5 between 400 to 600. In a preferred embodiment, wherein the aluminum oxide layer has a roughness depth Ra of less than or equal to 0.1 mymeter, preferably greater than 0.06 mymeter, are Sliding properties of the iron soleplate are good enough if the adhesion is not too high.

In a preferred embodiment of the electric iron, the Outer surface of the soleplate with the exception of one or more cutouts consistently on an aluminum oxide layer and at least one of the free spaces electrically connected to the iron block, it becomes an electrical Ground connection of the soleplate with the iron block or the earth guaranteed. This exemption can be done by grinding the non-conductive aluminum oxide layer or by covering individual areas of the Iron soleplate before placing it in an acid bath, i.e. before manufacturing the Aluminum oxide layer can be achieved.

An embodiment of the invention is shown in the drawing and is in following described in more detail.

Fig. 1

Teilquerschnitt durch den Schichtaufbau eines mit einer Bügeleisensohle versehenen Bügeleisenblocks in vergrößertem Maßstab,

Fig.2

Teillängsschnitt durch die Oberfläche der Bügeleisensohle nach dem ersten Oberflächenbearbeitungsvorgang,

Fig. 3

Teillängsschnitt durch die Oberfläche der Bügeleisensohle nach Aufbringen der Eloxalschicht,

Fig. 4

Teillängsschnitt durch die Oberfläche der Bügeleisensohle nach dem Poliervorgang der Oberfläche der Eloxalschicht.

Show it:

Fig. 1

Partial cross section through the layer structure of an iron block provided with an iron soleplate on an enlarged scale,

Fig. 2

Partial longitudinal section through the surface of the iron soleplate after the first surface processing operation,

Fig. 3

Partial longitudinal section through the surface of the soleplate after applying the anodized layer,

Fig. 4

Partial longitudinal section through the surface of the soleplate after polishing the surface of the anodized layer.

According to FIG. 1, the iron block 1 cast from die-cast aluminum is in the vicinity its peripheral edge distributed steam outlet holes 11, which connect the Steam to the opening 19 formed on the iron block 1 up to Create the evaporation chamber (not shown). As from Figures 1 to 4 emerges, the ironing surface 6 points upwards, as if the iron is upside down, would be rotated by 180 °. The iron block 1 is made of cast aluminum, which so that the material flows better into the mold or other mold when pouring, Silicon is added.

In the iron block 1 of FIG. 1, an electric heater 4 for heating the Iron blocks 1 cast in. On the surface 5 of the iron block 1 is by means of a heat-resistant and good heat-conducting silicone adhesive 7, one made of rolled sheet die-cut iron sole 3 glued on. In addition to the adhesive 7 can still further mechanical fasteners can be provided, such as on the soleplate 3 trained sheet metal tabs, which for the purpose of attaching the Iron sole 3 are bent during assembly so that they Grip iron block 1 in a form-fitting manner, but not in the drawing is shown. The adhesive 7 also serves to seal the Iron sole 3 opposite the iron block 1 in the area of Steam outlet holes 11 with each other.

The outer surface 15 of the soleplate 3 is shown in FIG. 1 with a Provided aluminum oxide layer 2, which, with the exception of cutouts 14, preferably is formed on the entire outer surface 15. The exemptions 14 represent after Fastening the soleplate 3 on the iron block 1 a metallic connection to the surface 5 of the iron block 1 ago.

Each steam outlet hole 11 opens into openings formed in the iron block 1 19, which may have a common longitudinal axis 20. But it is also conceivable that the opening 19 is formed by an upwardly open channel in which the Open the steam outlet holes 11. This saves individual, with the steam outlet holes 11 steam holes to be connected in the iron block 1, which the Manufacturing simplified during the casting process of the iron block 1 or the mold less expensive. The steam outlet hole 11 closes via a Edge area 13 on a bead 12 surrounding the steam outlet hole 11, which over the Edge area 9 with the radius R in the horizontally extending surface 8 of the Iron sole 3 runs in. Instead of the surrounding bead 12, this can also be done Steam outlet hole 11 directly over the radius R in the surface 8 of the soleplate 3 open, which is indicated in Fig. 1 by the dashed lines 16 is shown.

In Fig. 2 is a partial longitudinal section on an enlarged scale through the cross section of the Iron sole 3 shown in the area of its outer surface 8, but already after the first grinding or polishing process of the surface 8, but before the anodizing of the surface 8. In FIG. 3, the surface 6 of the aluminum oxide layer 2 is on the Iron sole 3 shown in cross section, which after the diving process Iron sole 3 according to FIG. 2 by an anodizing bath (not shown) on the surface 8 the soleplate 3 adjusts. The resulting surface roughness Ra is included already smaller than if the surface 8 of the soleplate 3 is not as shown in FIG. 2 was pre-ground or pre-polished. 4 is the surface 6 of the aluminum oxide layer 2 shown in cross section, which after the polishing of the surface of the 3 results in aluminum oxide layer 2.

The procedure for making the soleplate is as follows:

First, the surface 5 of the iron block 1 is calibrated or pressed, washed alkaline and degreased, the better adhesion of the adhesive 7 Surface roughness 5 for this purpose is greater than 1 mymeter. Regardless, the Iron sole 3 punched out of low-silicon rolled sheet and in the area of Steam outlet holes 11 depending on the formation of the annular groove or bead, embossed or deep-drawn or otherwise deformed, at the same time the transitions through the radii R and r are formed in their size of about 0.5 to 1 mm.

Regardless of this, the outer surface 8, which will later serve as the base for the The ironing surface 6 serves, as shown in FIG. 2, to be ground or polished until the after Rauhtiehe Ra given by the invention of not greater than 1 Mymeter results. Subsequently the soleplate 3 is immersed in an anodizing bath (not shown) that there is an aluminum oxide layer 2 on the outer surface 8 of the iron soleplate 3 results, the thickness of which is preferably 35 to 45 mm and the hardness is preferably 0.5 HV 480. Certain areas on the outer surface 15 should not be Aluminum oxide 2, as is the case for example with the free space 14, coated be so, for example by means of wax, lacquer, silicone or other Covering agent covered. As a result, these locations 14 remain free of aluminum oxide 2. Degreasing or cleaning processes are carried out after or before, depending on the requirements applied to every operation.

After the anodizing bath, which takes about as long until the one shown in FIG Roughness Ra of 0.5 mm on the surface 6 of the aluminum oxide layer 2, then the surface 6 of the aluminum oxide layer in a further polishing process 2 by polishing to the roughness depth Ra of less than 0.1 shown in FIG. 4 Brought my meter. Then the one to be glued to the iron block 1 Top 17 with a temperature-resistant and good heat-conducting silicone adhesive 7 provided and pressed onto the surface 5 of the iron block 1. At the same time 3 tabs formed on the soleplate of the iron (not shown) are bent over until they grip the iron block 1 in a form-fitting manner. As a result, the soleplate 3 forms a mechanical one in addition to the adhesive 7 Connection to the iron block 1.

The finished soleplate 3 including the iron block 1 can now be used with the still necessary parts (not shown) to form an iron be assembled together. The electric heater 4, which is already when pouring the Iron block 1 was cast in these, generated during operation of the iron Heat generated by the adhesive 7 and the aluminum oxide layer adjacent to the adhesive 7 2 penetrates into the soleplate 3, from where the heat then again through the outer Aluminum oxide layer 2 is passed to the ironing surface 6. There it will be during the Ironing on the ironing not shown in the drawing, such as Items of clothing. The fact that the adhesive 7 is a good heat conductor and in is intimate contact with the soleplate 3, the heat is good on the Transfer soleplate 3.

Claims (5)

Method for producing an electric iron in which an iron block is cast from silicon-containing aluminum with a heater, and the surface forming the ironing surface is formed as an aluminum oxide layer,
characterized,
that a plate-shaped iron sole made of low-silicon aluminum is attached to the iron block in such a way that both are in good thermal contact, that the aluminum oxide layer is produced on the outer surface of the iron sole that forms the ironing surface, and that the aluminum oxide layer is formed by means of an anodizing process. A method of manufacturing an electric iron according to claim 1,
characterized,
that a 20 to 80 mm thick aluminum oxide layer is applied to the soleplate of the iron. A method of manufacturing an electric iron according to claim 1,
characterized,
that the outer surface of the iron soleplate before and / or after the generation of the aluminum oxide layer mechanically, for. B. is processed by grinding or polishing. Method according to claim 1,
characterized,
that the soleplate is glued to the surface of the iron block using a temperature-resistant silicone adhesive. Method according to claim 1,
characterized,
that at least a portion of the outer surface of the soleplate is covered during anodizing in such a way that this portion forms an electrically conductive free space after the anodizing process.

Images