Sealing device

Abstract

Sealing device for sealing two mold tool parts, comprising at least one elastically deformable sealing profile strand (1) with a predefinable length and with a substantially U-shaped cross-section, and comprising end caps (2) which can be attached to one or both ends of such a sealing profile strand (1), wherein the surfaces of the end caps (2) facing the ends of the sealing profile strand (1) are designed such that, in the attached state, a tight connection is formed between an end cap (2) and the sealing profile strand (1), wherein at least the opening of the sealing profile strand (1) formed by the U-shaped cross-section is sealed by the end cap.

Description

[0001] The invention relates to a sealing device for molding tools, which are used in particular for the production of foamed plastic molded parts.

[0002] In the field of polyurethane processing (PUR processing for short), molds with inflatable sealing devices are used, particularly in the backfoaming of automotive instrument panels. The seal prevents foam from escaping during the expansion phase of the PUR foam. The seal closes the gap between the skin and the carrier by pressing the skin against the carrier using the inflatable seal in the area of ​​the parting line between the mold halves. Inflatable round cords made of silicone or latex are typically used for this purpose. The individual round cord pieces are joined together via suitable connectors to form a closed sealing device that completely encloses the mold cavity. The required compressed air can also be introduced into the interior of the inflatable sealing device via the connectors. One such type of sealing device is known, for example, from document EP2907643B1.

[0003] The disadvantage of this type of seal is the predefined layout with the connections and compressed air supply. Therefore, the entire sealing system must be defined in advance and incorporated into the design and construction of the mold.

[0004] Based on this, the invention is based on the object of providing a sealing device characterized by a comparatively high degree of flexibility. In particular, a flexible division of the sealing circuits should be possible even after the production of a mold.

[0005] This object is achieved by a sealing device having the features of claim 1. Advantageous embodiments and further developments can be found in the dependent claims.

[0006] According to a core concept of the present invention, the operating principle is changed in that the sealing device itself is not inflatable, but rather the "inflating" takes place via the sealing seat. The sealing device and the sealing seat together form a pressure chamber that is pressurized with compressed air. The compressed air connection is no longer part of the actual sealing device, but is located in the sealing seat.

[0007] Accordingly, the sealing device comprises at least one elastically deformable sealing profile strip with a predeterminable length and a substantially U-shaped cross-section, and end caps which can be plugged onto one or both ends of such a sealing profile strip. The surfaces of the end caps facing the ends of the sealing profile strip are designed such that, when plugged in, a tight connection is formed between an end cap and the sealing profile strip, wherein at least the opening in the sealing profile strip formed by the U-shaped cross-section is sealed by the end cap. The U-shaped opening of the sealing profile strip points downwards in the direction of the groove into which the sealing device is installed. In this respect, a pressure chamber is formed from the interaction of the groove and the sealing device.Under the influence of compressed air, the sealing profile strip is supported in the seal seat via the sides of the U-shaped opening, which can also be referred to as lips, and seals. The end pieces form outer walls that enclose the pressure chamber and seal it along the length of the sealing profile strip.

[0008] According to one embodiment, the end cap on the side of the sealing profile strip can have a sealing pin protruding from the surface of the end cap with a cross section matching the U-shaped cross section of the sealing strip, such that the end cap, in the plugged-on state, protrudes with its sealing pin into the opening of the sealing strip formed by the U-shaped cross section.

[0009] According to a further embodiment, the end cap can have a mounting pin protruding from the surface of the end cap on the sealing profile strip side. The sealing profile strip can be conceptually divided into an open area and a closed area. The open area is formed by lateral lips that run upwards and merge into a closed area. It can also be said that the closed area connects the two lips to one another. The U-shaped cross section of the sealing profile strip is therefore preferably designed such that the sealing profile strip has a U-shaped, open area formed by lateral lips and corresponds to the opening of the U-shaped cross section, and preferably such that the sealing profile strip has a closed area that connects the two lips to one another.The sealing profile strip can have a recess at its end in the closed area, with a cross-section corresponding to the cross-section of the mounting pin. This allows the end cap with the mounting pin to be inserted into one end of the sealing profile strip.

[0010] Furthermore, the end caps can have, on their side facing away from the sealing profile strip, a region with a structure that essentially corresponds to the negative of a structure of a connecting element. With such a connecting element, two sealing profile strips provided with end caps can be connected to one another. The connecting piece preferably has a retaining pin with which the connecting element can be fixed in position in a groove of a mold part, in that the groove has an opening for receiving the retaining pin, in particular a blind hole-shaped opening.

[0011] The invention further relates to a molding tool for foaming plastic molded parts, in particular vehicle parts, comprising two mold halves, namely an upper tool part and a lower tool part, which can be moved towards and away from each other in a vertical direction, wherein, in a closed state, a cavity is formed in the molding tool, which cavity is formed by a partial cavity in the upper tool part and a partial cavity in the lower tool part. A groove is provided in one of the mold halves, in particular in the lower tool part, wherein at least one opening is present in the groove, which is connected to a channel via which compressed air can be introduced into the groove or via which a vacuum can be generated in the groove.A sealing device according to the invention is incorporated into the groove, wherein the sealing device is arranged in the groove such that the opening of the U-shaped sealing profile strip is oriented toward the bottom of the groove. The width of the groove should preferably correspond substantially to the width of the sealing profile strip.

[0012] The depth of the groove can be designed and matched to the height of the sealing profile strand in such a way that when compressed air is applied to the groove, the sealing profile strand is at least partially pushed out of the groove and pressed against the opposite mold half or against an insert located in the opposite mold half.

[0013] The invention will be explained below using an embodiment and with reference to the Fig. 1 to 7 are described in more detail. They show: Fig. 1 perspective view of a sealing device according to the invention in the disassembled state; Fig. 2 perspective view of a sealing device according to the invention in the assembled state; Fig. 3 Top view of a tool lower part with an inserted sealing device according to the invention; Fig. 4 Section view AA from Fig. 3 with skin and support part; Fig. 5 like Fig. 4, but with pressurised sealing device; Fig. 6 enlarged view of an end cap; Fig. 7 Perspective view of the connection area of ​​two sealing devices according to the invention.

[0014] According to the Fig. 1, a sealing device according to the invention comprises a sealing profile strip 1 with a substantially U-shaped cross section in the lower region of the profile and two end caps 2. The end caps have a sealing pin 3 and a mounting pin 4 in the surface facing the sealing profile strip 1. The sealing pin 3 has a cross section matching the U-shaped cross section of the sealing profile strip 1, such that the end cap 2, in the plugged-on state, projects with its sealing pin 3 into the opening of the sealing strip 1 formed by the U-shaped cross section (see Fig. 2). The sealing profile strip 1 can be conceptually divided into an open area and a closed area. The open area is formed by lateral lips 5 that run upwards and merge into a closed area. One can also say that the closed area connects the two lips 5 to one another. The open area has a substantially U-shaped cross-section that is open downwards. In the closed area, the sealing profile strip has a recess 6 that has a cross-section that corresponds to the cross-section of the mounting pin 4. In the example shown here, the mounting pin 4 has a circular cross-section and consequently the recess 6 also has a circular cross-section. The recess 6 must be at least as deep as the length of the mounting pin 4. The recess 6 can also be designed as a continuous channel that extends over the entire length of the sealing profile strip 1.By means of the mounting pins 4, the end caps 2 can be placed onto the ends of the sealing profile strand 1, whereby at the same time the sealing pins 3 at the two ends of the sealing profile strand are retracted into the U-shaped cross-section bordered by the lips 5.

[0015] The Fig. 3 to 5 show a sealing device according to the invention in the installed state. Fig. 3 shows a plan view of a lower tool part 7 of a molding tool. In the center of the lower tool part 7 there is a groove in which a sealing device according to the invention is located, which consists of a sealing profile strip 1 and two end caps 2 attached to the sealing profile strip. In the sectional view of Fig. 4 and Fig. 5, a carrier part 8 and a skin 9 are also shown. Typically, the carrier part 8 is held by the upper tool part (not shown here). The skin 9 rests on the lower tool part 7 and covers the sealing device consisting of the sealing profile strand 1 and the two attached end caps 2. Further details of the sealing device according to the invention can be seen from the sectional views, which have already been described in connection with the Fig. 1 and Fig. 2, namely the sealing pins 3 and the mounting pins 4. The recess 6 is designed here as a continuous channel. Of the lateral lips 5 of the U-profile, only the rear lip 5 is visible. The U-shaped recess of the sealing profile strand 1 and the end caps 2, together with the associated groove in the lower tool part 7, form a pressure chamber which can be pressurized with compressed air. For this purpose, a channel 10 is provided in the lower tool part 7. The channel 10 extends to an opening 11 in the groove which contains the sealing device. The groove in the lower tool part 7 forms the seal seat. Fig. 5, the pressure chamber is filled with compressed air, which has been introduced via the channel 10 and the opening 11. As a result, the sealing device as a whole has been moved slightly upwards out of the groove. A gap 12 has been formed between the lower end of the lips 5 and the bottom of the groove. Gaps have also formed between the underside of the end caps 2 and the lower part of the tool 7 (see arrow 13 in the Fig. 5). The skin 9 is pressed against the support part 8 by the sealing device and lies tightly against it.

[0016] In the enlarged view of an end cap 2 in the Fig. 6 shows that a mounting molded part 14 with a semi-cylindrical structure is formed in the lower area on the rear side of the end cap 2. The mounting molded part 14 is thus provided on the side of an end cap that, when installed, faces away from the end of the sealing profile strip.

[0017] As from Fig. As can be seen in Figure 7, two sealing devices can be brought together with their respective end caps 2a and 2b and placed against one another. A connecting element 15 with a retaining pin 16 and a structure matching the structure of the assembly mold part 14 serves to fix the position in the seal seat. The structure of the assembly mold part 14 thus corresponds at least substantially to the negative of the structure of the connecting element 15. A suitable opening is provided in the groove in the mold part, in particular in the manner of a blind hole, into which the retaining pin 16 can be inserted. The result is a positive connection between two sealing devices via the connecting element 15 and a common positional fixation in the mold part by means of the retaining pin 16. List of reference symbols 1 sealing profile strip 2 end caps 3 sealing pins 4 mounting pins 5 lips 6 Recess 7 Tool base 8 Support part 9 Skin 10 channel 11 Opening 12 gap 13 gap 14 Mounting molding 15 Connecting element 16 retaining pins QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 2907643B1

[0002]

Claims

[1] Sealing device for sealing two mold parts, comprising at least one elastically deformable sealing profile strand (1) with a predeterminable length and with a substantially U-shaped cross-section, and comprising end caps (2) which can be plugged onto one or both ends of such a sealing profile strand (1), wherein the surfaces of the end caps (2) facing the ends of the sealing profile strand (1) are designed such that, in the plugged-on state, a tight connection is formed between an end cap (2) and the sealing profile strand (1), wherein at least the opening of the sealing profile strand (1) formed by the U-shaped cross-section is sealed by the end cap. [2] Sealing device according to claim 1, characterized bythat the end cap (2) on the side of the sealing profile strand (1) has a sealing pin (3) protruding from the surface of the end cap (2) with a cross section matching the U-shaped cross section of the sealing profile strand (1), such that the end cap (2) in the plugged-on state projects with its sealing pin (3) into the opening of the sealing strand (1) formed by the U-shaped cross section. [3] Sealing device according to claim 1 or 2, characterized bythat the end cap (2) has, on the side of the sealing profile strip (1), a mounting pin (4) protruding from the surface of the end cap (2), that the U-shaped cross section of the sealing profile strip (1) is designed such that the sealing profile strip has a U-shaped, open region which is formed by lateral lips (5) and corresponds to the opening of the U-shaped cross section, that the sealing profile strip (1) has a closed region which connects the two lips (5) to one another, and that the sealing profile strip (1) has, at its end in the closed region, a recess (6) which has a cross section which corresponds to the cross section of the mounting pin (4). [4] Sealing device according to one of the preceding claims, characterized bythat the end caps (2) have, on their side facing away from the sealing profile strand (1), an area with a structure which essentially corresponds to the negative of a structure of a connecting element (15), this area forming a molded assembly part (14) with which two sealing profile strands (1) provided with end caps (2) can be connected to one another, the connecting piece (15) preferably having a holding pin (16) with which the connecting element (15) can be fixed in position in a groove of a mold part (7), in that the groove has an opening for receiving the holding pin (16), in particular a blind hole-shaped opening. [5] A mold for foaming plastic molded parts, in particular vehicle parts, comprising two mold halves, namely an upper mold part and a lower mold part, which can be moved vertically toward and away from each other, wherein, in a closed state, a cavity is formed in the mold, which is formed by a partial cavity in the upper mold part and a partial cavity in the lower mold part, wherein a groove is provided in one of the mold halves, in particular in the lower mold part (7), wherein at least one opening (11) is present in the groove, which is connected to a channel (10) via which compressed air can be introduced into the groove or via which a vacuum can be generated in the groove, and wherein a sealing device according to one of the preceding claims is introduced into the groove, wherein the sealing device is arranged in the groove in such a way thatthat the opening of the U-shaped sealing profile strip (1) is aligned towards the bottom of the groove., [6] Mould according to claim 5, characterized by that the width of the groove essentially corresponds to the width of the sealing profile strand (1). [7] Mould according to claim 5 or 6, characterized by that the depth of the groove is designed and matched to the height of the sealing profile strand (1) in such a way that the sealing profile strand (1) is at least partially pushed out of the groove when compressed air is applied to the groove and is pressed against the opposite mold half or against an insert part or a carrier part located in the opposite mold half.

Images