Gasket assemblies

The invention relates to a method for producing gaskets which have a carrier plate on which, in the region of openings, pads of liquid or paste-like sealing material are arranged and dried or hardened.

Seals, which have a support plate with arranged in the region of openings pads are known in its objective embodiment of the German Patent 922 452. According to British Patent Specification 852 413, it has already been proposed to produce such seals by means of the injection molding process. However, as is common knowledge, the injection molding can be used in consideration of economic aspects only in the event of large numbers, since the cost of the required extruder and the injection molds are very high. In the production of small quantities, the injection molding process is therefore practically unusable. In addition, gaskets produced by injection molding must be reworked on their ridges and the spray lugs. From US Pat. No. 2,289,620 it is further known to spray a metal adhesive layer onto a gasket carrier plate using a template. The disadvantage of this method is also that it requires a relatively large amount of equipment for the spray system. In addition, relatively much adhesive material is lost during spraying, and the thickness of the adhesive layer is difficult to dune.

The object of the invention is to provide a method of the type mentioned, which allows primarily economical production of only be produced in small numbers seals.

This object is achieved according to the invention in that the supports are applied by way of the known screen printing process.

In a screen printing process, the ink passes through a screen onto the article to be printed, the application of the ink to the article to be printed being controlled by a stencil, which is usually placed between the screen and the article to be printed and usually affixed to the screen. The ink is usually pressed by a roller squeezer during a R6lativbewegung between this squeegee on the one hand and the screen, the template and the object to be printed on the other hand through the screen on the object to be printed. The application of this method to the production of seals, wherein the ink is replaced by the seal material for the production of the pads and the object to be printed by the carrier plate, minimizes the required manufacturing device. As mentioned above, only a squeegee, a screen and a stencil according to the desired edition form are required. The inventive method also provides the advantage that no sealing material is wasted, since this is attached exclusively to the desired, predetermined by the stencil locations. It is also possible, without much precautions, to produce a variety of seal shapes, it only needs the template to be replaced; The seals produced by the process according to the invention also do not require any further processing insofar as practically no appreciable burrs or even spray bumps are formed.

For the invention, it is in any case irrelevant whether the openings are formed in the carrier plate before or after applying the pads.

Furthermore, it is within the scope of the invention, when the pads are applied to an intermediate carrier and transferred from this to the carrier plate. In this way, a particularly accurate production of the applied pads is possible. According to another feature of the invention it is provided that the pads are pressed during drying, so that their surfaces are then particularly smooth. There are many gasket materials, e.g. B. Acryluitrilgummi and silicone rubber. These may require a solvent and may contain fillers and / or binders. An adhesive may be necessary to achieve adequate adhesion between the pads and the backing plate. The support plate may be made of different materials, such as a metal or a synthetic plastic, as well as the intermediate carrier, if one is used. It may be coated with a release agent to facilitate removal of the annular pad or pads from the sealing material.

Embodiments of the invention are explained below with reference to drawings. 1 is a plan view of a seal according to an embodiment, F i g. 2 shows a section through the seal according to the line 2-2 in FIG. 1, F i g. FIGS. 3 and 4 are perspective views of seals according to further embodiments; FIG. 5 is a section of a part of a seal according to another embodiment, FIG. 6 a plan view of a seal according to another embodiment, F i g. 7 is a section along the line 7-7 of F 1 g. 6, F i g. 8 is a plan view of a seal according to another embodiment, FIG. 9 is a section along the line 9-9 of FIG. 8, F i g. FIG. 10 shows a section of a seal according to a further embodiment, FIG. 11 is a section along the line 11-11 of FIG. 10, F i g. FIG. 12 is a plan view of a gasket according to still another embodiment; FIG. 13 and 14 ways to press the sealing material during drying, F i g. 15 mold plates for shaping during pressing, F i g. 16 a seal before pressing, F i g. 17 the seal according to F i g. 16, while from the mold plates according to FIG. 15 is pressed, F i g. 18 the seal after molding and F i g. Figure 19 shows another way of molding during pressing.

Of the drawings, FIG. 1 and 2 a seal including a support plate 1, which is formed as a disc with three openings 2 of different size and shape, which extend from one end face to the other. Ring-shaped supports 3 of sealing material are applied or transferred to both ends of the support body 1 so that each annular support 3 surrounds an opening 2. This seal is intended for use between two parts having passages corresponding to the location of the openings 2, and the seal has screw holes 4 through which bolts fit to connect the parts.

The sealing material is in annular supports 3, which surround each opening 2. This provides a significant saving in sealing material over known type of gaskets made in other ways, where the gasket material covers the face of the backing plate, and it provides a seal with better sealing properties than these known gaskets.

F i g. 3 shows another seal. Similar parts are identified by the same reference numeral. F i g. 4 shows a seal in which the sealing material is better applied on the end face of a connecting part 5 than on a sheet-like element which is inserted between two parts.

F i g. 5 shows a seal in which openings 7, 8 are connected to one another on opposite end faces of the carrier plate 6, but are not symmetrical opposite each other.

F i g. 6 and 7 show a seal in which a further annular support 9 of the sealing material has been applied or transferred to each of the first annular supports 3, the further annular supports 9 being of smaller width than the first annular supports 3.

F i g. 8 and 9 show a seal in which a further portion 11 of sealing material has been applied or transferred to each of the first annular supports 3. All other parts 11 differ in their thickness, which is generated by changing the thickness of the stencil during the screen printing process or by shaping during drying.

F i g. Figures 10 and 11 show a seal in which the annular supports 3 change in thickness. F i g. 12 shows a seal in which the annular support 3 changes in width and is closest in the vicinity of the two screw holes 4. When such a gasket is screwed between two parts, a small amount of elastic bending is possible without losing the sealing properties.

F i g. Fig. 13 shows an embodiment for pressing the annular supports 3 of three seals during drying by means of a base plate 12, cutting wheels 13, a cover plate 14 and a weight 15.

F i g. Fig. 14 shows another way of pressing the annular layers during drying, with spacers 16 and a screw clamp 17. The spacers 16 have a predetermined thickness to determine the final thickness of the annular supports 3. *** "

F i g. FIG. 15 shows two press plates 18 shaped so that the annular supports 3 change in thickness from a maximum at their inner circumference to a minimum value at their outer circumference when a gasket according to FIG. 16 during drying, z. B. in the manner as in F i g. 17 is pressed.

F i g. Fig. 19 shows still another kind of pressing while drying. The seal is located between two thin metal plates 18, and between each plate 18 and the base plate 12 and the pressure plate 14 is an elastic buffer 19. spacers 21 of different thickness are located between the plates 18 and give the final thickness of the annular pads. 3

Thus, the use of a screen printing method in the manufacture of gaskets in which one or more annular pads of gasketing material are applied or transferred to an end face of a backing plate allows the or each annular bead to surround an opening on the face of the plate so that the seals be made in a variety of shapes and properties.