DE2940767A1 - METHOD FOR FIXING A METAL FITTING ON A NON-METAL PART - Google Patents

Description

29A0767

_ 4 - - ⁸ OCT. 1979

METHOD OF FIXING A METAL FITTING ON A NON-METALLIC PART

Addition to patent no. 23 61 643

The subject of the main patent is a method for fastening a fitting on a non-metallic one Part by injection molding the metal or alloy of the fitting onto the head of the non-metallic part, whereby one or more metal sleeves are firmly attached beforehand to at least part of this head.

Under certain circumstances, difficulties arise with the technique described in the main patent. at a sleeve made of aluminum or an aluminum alloy, which is attached to a head of an electrical insulator made of glass is pressed, the combined action of temperature and pressure during the injection of the molded cap of the Insulator-forming metal lead to the metal sleeve on the hard glass surface, especially in the direct metal flow exposed area, adheres. Such adherence is undesirable because it occurs in the glass surface when it cools Small cracks can be created to a depth of 5 to 50 microns.

To solve this problem, thought was given to using lubricants or mold release agents such as molybdenum bisulfide to use in aerosol form, however, the

030017/0777

The results are not entirely satisfactory because, on the one hand, metal is still quite often found in the hottest area adheres to the glass surface and, on the other hand, under the action of heat, the mold release agent or lubricant becomes a gas release, which can lead to bubbles between the metal sleeve and the glass.

The invention therefore aims to propose a method by means of which the method described in the main patent is improved by reducing the risk of metal sticking to a hard glass surface, particularly in the combined effects of temperature and injection pressure of liquid metal in the most exposed area, considerable is decreased.

The invention thus relates to a method for fastening a fitting on a head-shaped, non-metallic one Part by injection molding the metal or alloy of the fitting onto the head of the non-metallic Part, at least one or more metal sleeves are firmly attached to at least a part of this head, according to Patent No. 23 61 643, characterized in that one layer made of glass fibers, which covers at least the area of the head in which the liquid metal is injected arrives, and which contains an anti-sticking inert mineral, the layer of glass fibers when applied of the metal sleeves on the head of the non-metallic part between this head and the metal sleeves under compression is arranged.

0300 1 7/0777 ./.

With regard to features of preferred embodiments of the invention, reference is made to the subclaims.

The invention is described below using an exemplary embodiment with reference to the enclosed five figures explained in more detail.

Fig. 1 shows an axial section through a cap insulator and its shaft, in which on the fastening head a metal sleeve is applied with a bead and in the case of the invention between the sleeve and the fastening head a Glass fiber layer with an inert mineral is present.

Fig. 2 shows the detail A from Fig. 1 in an enlarged view.

Fig. 3 shows schematically how the glass fiber layer is prepared.

Figures 4 and 5 show how this glass fiber layer between metal sleeve and fastening head before spraying the cap to be cast.

The insulator shown in Fig. 1 consists, according to the main patent, of a plate 1 made of hard glass * which is attached, for example, to the upper end of a metal shaft 11 · on the plate 1 is a thin metal sleeve 2 arranged with an edge bead 20, which is easily deformable and preferably consists of a heat-conductive metal; this metal shell is made by electromagnetic forming or by isostatic pressing, i.e. by crushing a Elastomer cylinder applied tightly over the sleeve on the head 3 of the plate; on the plate with its metal sleeve a fitting is then applied by casting,

030017/077? ./.

29A0767

which in the present example has the shape of a metallic cap 4.

To prevent the metal sleeve from sticking to the head of the plate, especially in the area where the To prevent liquid metal from arriving during casting of the cap, a glass fiber layer 101 is provided according to the invention, which covers at least the zone that is particularly stressed during the casting process and one that prevents adhesion contains inert mineral; this glass fiber layer is thus between the head 3 and the metal sleeve 2 during application this metal sleeve compressed on the head. Based

In the section of Fig. 2, the various in Fig. 1 ^ shown Layers better distinguished by enlarging section A. will.

The fiberglass layer is very thin and has a

2 2

Basis weight from 10 g / m to 50 g / m, preferably from

about 26 g / m.

The glass fiber layer contains a powdery inert mineral, preferably essentially talc or aluminum oxide; the presence of an inert mineral avoids any gas separation, and unlike lubricants there is no risk of foreign matter contamination.

3 shows an example of a method by which the glass fiber layer is provided with the mineral. here

the fiberglass layer 101 runs (in the form of a not yet in the later

'desired shape of cut tape) by a talc or Alumina fluid bath, which is made in a container 102

030017/0777 .A

in the lower part of which a compressed air supply 103 is provided under a porous plate 104. The subsequently The glass fiber layer 101 cut to the desired shape is then produced by pressing the corresponding Surfaces of the hard glass (fastening head 3) and aluminum sheet (metal sleeve 2) as in Fig. 4 schematically depicted crushed. When the glass fiber layer is placed in the bottom of the sleeve, this glass fiber layer 101 has a shape which rests precisely on the bottom of the sleeve and on the side walls near the bottom, this shape being compressed obtained when placing and pressing the sleeve on the fastening web as indicated schematically in Fig. 5 will. Of course, the fiberglass layer can also be the entire Cover the inner surface of the metal sleeve including possibly the underside of the bead. It is then sufficient to use the its fiberglass layer and the applied metal sleeve provided part in such a way that between the Inner walls of the mold, the outer surface of the metal sleeve and a seal between the mold and the plate (the Bead 20 this seal) a space is left free by casting a molten metal or a molten alloy to be obtained cap 4 corresponds; in the case of an aluminum cap, the temperature of the molten metal is about 680 C. As described in the main patent, is prevented by the metal sleeve 2 that the molten metal directly on the non-metallic

030017/0777 ^{m / m}

Material, glass or ceramic, so that consequently the thermal shock is reduced; when the molten one hits Metal, the metal sleeve is heated, but because of its good thermal conductivity this heat is distributed the entire surface of the head 3 and in this way dampens the locally occurring thermal stresses. Thanks to the improvement according to the invention, any sticking of the metal sleeve to the glass is avoided; aside from that the cracking of the glass surface on cooling becomes considerable decreased.

In the example described here, the shape was the

not only glass fiber layer 101 so that it covered the bottom of the sleeve, however, within the scope of the invention, a simple disc which only covers the bottom of the sleeve can be provided; when the metal or alloy is injected from the side, a cylindrical sleeve fulfills the same purpose, the VDr the application of the metal sleeve placed on the head and at least covers the area where the liquid metal strikes during injection. The fiberglass layer can also be preformed before insertion.

Furthermore, it can prove to be advantageous to use the area of the head that is not covered by the glass fiber layer is to be coated with an inert mineral prior to placing the metal sleeve, similar to that contained in the fiberglass layer Mineral corresponds.

030017/077?

29A0767

The main function of the fiberglass layer is apparently to act as a carrier for an inert mineral serve, with thermal insulation occurring as an otherwise beneficial side effect; the essential function of the inert minerals consists in creating an adhesion between glass and metal sleeve without contamination or release of Avoid gases.

Ό30017 / Ο717

Blank page

Claims (1)

Fo Il 441 D CERAVER S.A. 12, rue de la Baume 75008 PARIS, France METHOD OF FIXING A METAL FITTING ON A NON-METALLIC PART Addition to patent 23 61 643 PATENT CLAIMS 1 - Method of fastening a fitting on a head-shaped, non-metallic part by injection molding of the metal or alloy of the fitting on the head of the non-metallic part, with at least on one or more metal sleeves are firmly attached to a part of this head in advance, according to patent no. 23 61 643, characterized in that a layer of glass fibers (lOl) is inserted between the at least the The area of the head (3) where the liquid metal arrives when it is injected and which prevents it from sticking contains inert mineral, whereby the layer of glass fibers when the metal sleeves (2) are applied to the head (3) of the non-metallic part (1) is placed between this head and the metal sleeves under compression. 030017/077? 2 - The method according to claim 1, characterized in that when using a Metal sleeve in the form of a cap (2) made of a metal with good thermal conductivity, the glass fiber layer (101) is a disk, which is placed in this cap before the cap is applied. 3 - The method according to claim 1, characterized in that the glass fiber layer (101) when pressing the sleeve (2) onto the head (3) of the non-metallic Partly is shaped into a dome, which is exactly on the corresponding area of the inner wall of the sleeve is present. 4 - The method according to claim 1, characterized in that the glass fiber layer Has the shape of a cuff that covers at least the side area of the head (3) in which the injected liquid metal arrives. 5 - Method according to one of claims 1 to 4, characterized in that the possibly with the glass fiber layer not coming into contact surface of the head before the application of the metal sleeve or sleeves with a Inert mineral is coated, which corresponds to the inert mineral contained in the glass fiber layer and a lubricant forms. , 030017/0777 6 - method according to one of claims 1 to 5, characterized in that the glass 2 fiber layers (101) have a weight per unit area of 10 g / m 2 2 to 50 g / m 2, with 26 g / m 2 being a preferred value. 7 - method according to one of claims 1 to 6, characterized in that the inert mineral contained in the glass fiber layer (101) is essentially is a powdery substance such as talc or clay. 030017/077 * ./.