Connection structure, has annular cover pressed on air seal that is interposed between inserted metallic parts and plastic piece, where bottom part of structure is provided with outer nut that is connected with spiral ear of metallic parts

ES 2 220 175 A1

DESCRIPTION

Coupling an insert in plastic parts. Object of the invention

The invention consists of a coupling of a preferably metallic insert in plastic parts that has an arrangement of said insert similar to those that are usually embedded in the plastic material itself during the molding process of that plastic part.

In the present invention we are talking about a preferably metallic insert that determines the inlet and fixing pin of a tap for filling toilet cisterns.

The product obtained is a set where, optionally, a sealing gasket participates in order to avoid fluid leaks.

Background of the invention

The metal inserts or any other material are conventionally applied to the mold where the plastic injection will take place that will give rise to the corresponding part, the inserts being embedded in the plastic material itself.

This type of insertion tends to pose problems of cracking of the material that surrounds the metal body, even leading to difficulties in keeping it stable.

Let us bear in mind that we are facing a process of hot joining of a metal part and a plastic material, with different coefficients of expansion and very different physical behaviors in working conditions at high temperatures, where the plastic part has a high temperature while the metal part or insert has a much lower temperature. In addition, these different coefficients of expansion and contraction are reflected in a very significant way in finished and in-use parts that are subjected to different temperature environments.

Description of the invention

To achieve the objectives and avoid the drawbacks mentioned in the previous sections, the invention proposes a coupling of an insert in plastic parts consisting of a set where a sealing gasket optionally participates to prevent fluid leaks between a preferably metallic insert and a part. plastic support where such insert is attached with the help of a cover that presses on the sealing gasket, once the assembly is assembled.

Both the insert and the support part are of a tubular or hollow structure, so that it is essentially applicable to toilet cisterns, where the support part constitutes the housing or base of a tank filling valve, located within said tank. , while the metal insert constitutes the threaded pin for fixing a hose associated with a tap connected to fill tanks, noting that conventionally the insert and support piece constitute a single integral assembly obtained during the plastic injection of such plastic piece, with the consequent derived problems referred to in the previous section.

The constitutive part of the valve base or other plastic part that ultimately opens into a valve body, has a stepped mouth where an end section of the insert is complementary, which in turn includes an annular projection.

The sealing gasket sits on the free face of such annular projection, which also surrounds the tubular structure of the insert, so that on the free part of that seal and on the annular projection surrounding it, the lid that has a channel presses where a part of that joint fits.

The whole assembly is immobilized on the bottom or side wall of a tank in correspondence with a hole in it, with the help of an external nut that will be coupled to the threaded pin of the insert, so that this nut will be arranged externally, while the lid will seat on the inner face of the tank.

The end part of the insert that fits into the stepped gap of the plastic part, includes in such end part an area that prevents a relative rotation between both associated elements: insert and plastic part.

In order to facilitate a better understanding of this specification, figures are attached below that represent the object of the invention for illustrative and non-limiting purposes.

Brief description of the drawings

Figure 1.- Shows an exploded perspective view of the coupling of an insert in plastic parts, object of the invention.

Figure 2.- Shows a sectional view where the coupling of the invention is shown on the side wall of a cistern.

Figure 3.- Shows a view of the coupling on the bottom of a cistern.

Description of the preferred embodiment

An example of embodiment of the invention is described below, taking into account the numbering adopted in the figures.

It is an assembly or coupling where two main elements participate: an insert 1 with a tubular structure and a hollow body made of plastic material that is housed inside a tank 2 and through which the tank is filled.

In a first case, the plastic part constitutes a supply valve 3 (figure 1), while in a second case, the plastic part constitutes an elongated element 3 'that ends at the end in a valve body, which in all cases regulates the water inlet to cistern 2 for filling.

In the first case, the plastic piece 3 sits on the side wall of the tank 2 in correspondence with a hole 4, while in the second case, the elongated element 3 'made of plastic material is installed on the bottom of that tank 2 in correspondence with another hole 4 '.

The insert 1 comprises in principle a conventional structure defined by a threaded pin 5 with a head 6 that fits in a complementary manner in a stepped recess 7 of the respective plastic part 3, 3 '.

That head 6 in turn includes an annular projection 8 and a hexagonal end 9 to prevent rotation in the coupling.

The free and front face of the annular projection 8 is flat and on it sits a sealing O-ring 10 which in turn fits into a channel 11 located on a cover 12 which in turn sits on the free face of such projection 8 and also on the mouth of the stepped hole 7 of the respective plastic piece 3, 3 '.

The entire described assembly is fixed by means of an external nut 13, which is coupled on the threaded pin 5 of the insert 1, a pin that for the most part

ES2 220 175 A1 protrudes from the outside of the tank 2, so that once the whole assembly is assembled, the cover 12 will seat on one side on the tank 2, while on the other side that cover 12 will seat on the annular projection 8 of the insert 1 and on the plastic piece 3, 3 'sealing that joint between said insert and plastic piece 3, 3'.

The cover 12 has a small front recess where a part of the annular projection 8 of the insert 1 is located, so that notches 14 of said annular projection 8 collaborate in the immobilization of said insert 1 preventing its rotation.

The cover 12 once mounted on the plastic piece 3 3 'is immovable and will preferably be glued to said location by means of adhesives, ultrasound or any technique that ensures a solid bond that guarantees a minimum portion to the joint 10 to avoid leaks.