NL8203001A - Injection moulding e.g. plastic pipe with socket end - and final shaping outside mould to secure e.g. lip seal ring before pipe fully cooled - Google Patents

Abstract

The arrangement is intended for manufacturing plastic pipe fittings or the like by injection-moulding in a mould (of which 3 are the removable inner parts) and removing each fitting from the mould before it is fully cooled to complete cooling away from the mould until fully set. Whilst outside the mould and before fully cooled, the fitting is subjected to a final shaping operation and only then fully cooled and allowed to set before final discharge. This shaping operation may be combined with the application of one or more previously manufactured components, e.g. lip seal rings, or such components may be formed (injection-moulded) in situ during that operation. Used for manufacture of e.g. plastic pipe fittings by injection-moulding followed by final shaping outside the mould before fully set. The arrangement makes it possible to manufacture a complete product incorporating the sealing rings or the like in the time of one moulding cycle, thus avoiding intermediate storage, re-heating, assembling the rings and final shaping to secure them, and the handling this involves.

Description

* 2 * - »82.5110 / vdV / Rdm / sme

Short designation: Method for manufacturing moldings and device for carrying out this method.

The invention relates to a method of manufacturing moldings, in particular plastic pipe fittings, using an injection mold, from which the injected object is removed before its total cooling and cooled to a form-retaining position outside the injection mold. .

The invention also relates to a device for carrying out this method, comprising an injection mold with a co-operating part for lifting a molded object out of the mold 10 and feeding this object to a processing station.

Such a method and device is described in the Dutch patent application 7311557, in which use mold cores removable from the injection mold are used, which serve as transport means and carrier for the not yet completely cooled moldings in order to transport them to a separate cooling station.

Another set of mold cores is now fed into the opened mold, after which the molds close again for injection molding of a next molding, while the previous molding is completely cooled in the cooling station.

The advantage of this is that no long cooling times are required with a closed injection mold, so that a faster production and thus more cost-effective use of the expensive injection mold is achieved.

The object of the invention is to extend this method, so that in one injection molding cycle a completely shaped product is obtained, which otherwise cannot be achieved in an injection cycle of the mold. This is possible because the new method consists in that on the molding outside the injection mold and before it has completely cooled, a change in shape of the still plastic "82 0 3 0 0 1" Hl - 2 - plastic of the part to be deformed is given and only then brought into a shape-retaining condition and removed. Still plastic plastic is understood to mean that shape changes can be effected by external forces and not the flow of the plastic by gravity.

Furthermore, with the new method it is possible to extend it thereby that the change of shape is effected with the addition of one or more objects independently manufactured from the molding.

Furthermore, the new method provides that the deformation is effected while simultaneously forming one or more object parts to be connected to the molding.

For the implementation of the new method, an apparatus of the type described at the outset can be used, which according to the invention is characterized in that the part co-operating with the injection mold is a conveying member which during the injection molding in the closed mold and after pressing press the molding from the mold after a post-forming station and then to a discharge station. The transport member can hereby go through a closed path. Furthermore, according to the invention, the conveyor is of multiple design and the components carrying the molding are positioned such that during injection molding in the closed mold, a previous molding is located in the post-molding station. The molding supporting components are moldings or engravings, which are removable from the injection mold and fit precisely into molded part carriers in the finishing station provided with means for sequentially feeding one or more independently of the molding manufactured objects.

An apparatus for further carrying out the method is further characterized in that the post-processing station comprises one or more injection molding machines and the supporting components fit in an 8203001 * - 3 - second injection mold and form a whole therewith.

The invention also relates to a molding, in particular a plastic pipe fitting manufactured by the method according to the invention.

The special feature of the new method is that it is possible to provide moldings with molded parts, in particular a pipe fitting provided with sealing collars, which are completely molded into the molding, without separate operations being required for mounting these sealing collars.

The moldings that come out of an injection mold do not need to be stored and then taken to a mounting table for mounting the sealing collars and then partially heated to fix the sealing collars by post-molding. The completely assembled product is now removed completely ready for use at each injection press cycle.

The invention will be explained in more detail with reference to the appended drawing, in which: Fig. 1 shows an axial section through a molding in a mold half with a mold core, also in axial section; Fig. 2 is an axial section of the molded piece shown in Fig. 1 placed in a finishing station outside an injection mold; Fig. 3 is an axial section through the fully finished molding, in the form of a connecting sleeve; Fig. 4 shows a schematic representation of a device for carrying out the method according to the invention; and Fig. 5 shows an axial section of a molding in a finishing station in a special embodiment.

In the drawing, a simple connecting sleeve for two pipes has been chosen for the production of a molding, in particular a pipe fitting made of plastic. In Fig. 1, this cross-sectional connection sleeve is generally indicated by the number 1.

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The connecting sleeve 1 is located in a mold half 2, which is provided with a separate mold shell 3, which is generally called engraving. These engravings are used to not manufacture the entire mold from expensive, high-quality material.

The engraving 3 is arranged to be able to form the outer jacket of the connecting sleeve 1. Two mold cores 4a and 4b serve to form the internal shape of the connecting sleeve 1. Like the mold with half 2 and, if necessary, also engraving 3, cores 4a and 4b are provided with channels 5 through which a heating medium can flow. Cores 4a and 4b are adapted to provide a connecting edge 6 and a collar 7, which serve to receive a sealing collar, for instance of rubber. In the mold, the engraving 3 with the cores 4a and 4b is thus brought into the correct position for forming the sleeve 1. Subsequently, the mold is closed, the mold half not shown with the engraving part coming onto the mold half 2 and the engraving 3. Plastic is then injected, while the pressure is maintained for some time after the injection.

Until now, the mold has been cooled in the usual manner in order to make the molding or sleeve 1 dimensionally stable.

In contrast to this, the injection molded part, i.e. the sleeve 1, is now removed before its total / cooling and cooled to a form-retaining position in a place outside the injection mold.

With the new method, the molding 1 outside the injection mold 2 and before it has completely cooled, is now given a shape change to the still plastic plastic of the molding 1 and only then brought to shape-retaining condition by cooling. However, the plastic condition of the molding is such that the material cannot flow out by itself. This will be elucidated with reference to Fig. 2. The connecting sleeve 1 is taken together with the engraving 3 from the injection mold 2 and for this purpose the engraving is provided with an arm 8 which forms part of a transport device.

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Outside the injection mold, the engraving 3 with the sleeve 1 has been placed in a molding device, which is provided with two caps 9a and 9b.

With the aid of these cooling cores, cuffs, for example of rubber 10 with their collar 11, are now placed behind the bumper 6 of the sleeve 5. To this end, the cooling cores 9a and 9b are provided with a configuration adapted to the cuffs 10. When the cooling cores 9a and 9b move towards each other, these cores slide into the material of the sleeve 1 which is not yet completely rigid. The sleeve 1 is therefore not yet completely cooled. Subsequently, molding edges 12 on the 10 caps 9a and 9b press the material of the collars 7 around the sleeve 10 which has now been placed in place, namely around the collar 11 thereof. Subsequently, a cooling medium penetrates through the channels 13 into the cores 9a and 9b, so that the connecting sleeve 1 is cooled down. If necessary, cooling can also be applied on the outside of the engraving 3. The engraving with the product or the sleeve 1 is thus positioned in the molding device, the caps with the sealing sleeves are inserted and are pressed by means of the collar 7. The molding device is then opened, the engraving with the now cooled molding or sleeve 1 is removed and taken to a discharge station, possibly under additional cooling, after which the engraving is opened at the discharge station and the product falls out.

The new method therefore consists in that the molding outside the injection mold and before it has completely cooled, a shape change is given to the still plastic plastic of the part to be deformed and only then brought into shape-retaining condition and removed completely. . Applying the change of shape takes place with the addition of one or more articles produced independently of the molding 10. As has been explained above, the application of one or more articles independent of the molding takes place before the still plastic material of the part to be deformed is deformed. As with reference to 8203001 «. η - 6 - Fig. 2, the deformation of the molding outside the injection mold is carried out using molding means 12 independent of the injection mold. Also, deformation of the molding or sleeve 1 outside the injection mold 2 is carried out using molding means associated with the injection mold, i.e. the engraving 3, which support the molding, and the molding means associated with the mold are hereby given a different position for deforming the object. For deformation of the object there is thus a cooperation of the molding means 12 independent of the injection mold 102 and the molding means or engravings 3 associated with the injection mold, which are brought together for this purpose.

Fig. 4 shows an apparatus for carrying out this method, which comprises an injection mold 2 * with a part 8 co-operating therewith for lifting a molded object out of the mold and sending it to a processing station, generally indicated by reference numeral 14 , feeding the object.

The part 8 cooperating with the injection mold 2 'is part of the engraving 3 and a transport member, which part of the engraving 3 remains with a part of the arm 8 during the injection molding in the closed mold 2' and after pressing the molding from the mold to a postforming station 14 and then to a discharge station 16. The transport member 15 is a hub 17, with three spokes 18 with an engraving 3 at the ends. The transport member 25 herein runs through a closed path. The conveyor 15 is thus of multiple design and the components carrying the molding (engraving 3) are positioned such that during injection molding in the closed mold, a previous molding is located in the post-molding station 14 and a previous molding in the discharge station 16. For correct positioning, the engravings 3, which can be removed from the injection mold, fit precisely into carriers 19 of the moldings 9a and 9b, with their edges 12 in the back

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8203 001 r? * - 7 - working station 14. The molded parts are therefore stamps that can perform a movement relative to the engraving placed in the finishing station. The finishing station 14 is provided with means 20 for successively oriented feeding of one or more articles manufactured independently of the molding, in this case the cuffs 10. This oriented feeding of the cuffs need not be described in more detail, since the appropriate measures are well known in mechanics. As stated with reference to Fig. 2, the post-processing station 14 is provided with cooling means (channels 13) for cooling the molding. When the carriers for the object move from the post-processing station 14 to the delivery station 16, they preferably go through a cooling path, for example in the form of a cooling tunnel 21.

The engravings 3, like the mold, are composed of two mold halves and each half carries an arm 8 pivotable relative to each other to move the engraving halves apart to eject the molding contained therein. With the aid of a roller 22 or cam, the arms can hinge apart when the roller 22 collides with a run-up cam 23. The moldings, in the preferred example a sleeve 1, can then fall out of the engraving and be removed on a conveyor belt 24. It is clear that other means of opening the engraving can also be used, and instead of an engraving, die cores can also serve as a transporting means, depending entirely on the nature of the post-processing applied to the still plastic material of the as-yet-uncured product. has to be done. The conveyor 15 can rotate with its hub 17 about, for example, one of the guide rods 25 of a mold plate 26 and can be rotated in accordance with the pressing cycle by means of a separate drive device 27.

The finishing station 14 can, for example, be mounted on a separate support plate 28, which is screwed, for example, on the mold plate 26. In accordance with the opening and closing trajectory, the conveyor 15 can also perform an axial movement in order to bring the engraving 3 in and out of a mold half. The same applies to the post-processing station 14.

Fig. 5 shows a special embodiment of the post-processing station 14, in which the engraving 3 together with the molding 1 forms part of the post-processing station. In this embodiment, the post-processing station 14 includes one or more injection molding machines, only one of which is shown in part, the nozzle of which is indicated by the reference numeral 30. Furthermore, the finishing station comprises a mandrel 9 'in the form of a second injection mold, in which the supporting components or the engraving 3 fits.

The molding 1 together with at least the second mold 9 'encloses a new molding cavity 28, which communicates with the spraying nozzle 30 via the injection channels 29. Furthermore, at the location of the mold cavity 28 in the second injection mold 9 ', a second space 12' closes in the mold or on the side of the wall of the molding 1 remote from the molding cavity 28, in which space a part of the molding fits after deformation. .

It is now possible to carry out the method according to the invention in such a way that the deformation is applied while simultaneously forming one or more object parts 10 'to be connected to the molding T and in that the formation of the one or more is independent of the molded articles 1 'is made by injection molding thermoplastics against a portion of the molded article. If the article 10 'is a sealing sleeve, thermoplastic rubber-like materials are used. Due to the pressure of the thermoplastics in the mold cavity 28 during spraying, a wall portion of the molding is reformed in accordance with the configuration of the cavity 12 'and a collar IT is formed on the object portion 10' which passes through the wall portion 7 '. of the molding 1 is held.

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In this case, the supply means 20 for the individual cuffs are omitted in the post-forming station 14.

8203001

Claims (17)

A method for manufacturing moldings, in particular tubular fittings of plastic, using an injection mold, from which the injected object is removed before its complete cooling and cooled to a form-retaining position outside the injection mold 5, characterized in that the molding outside the injection mold and before it has completely cooled is given a shape change to the still plastic material of the part to be deformed, and only afterwards is it fully retained and removed. Method according to claim 1, characterized in that the change of shape is effected with the addition of one or more articles independently manufactured from the molding. 3. Method as claimed in claims 1 and 2, characterized in that the application of one or more articles which are independent of the molding takes place before the still plastic material of the article is deformed. 4. A method according to claims 1 and 2, characterized in that the deformation is effected while simultaneously forming one or more articles to be connected to the molding. 1 2 3 4 8203001 Method according to one or more of claims 1 to 4, characterized in that the deformation 3 of the molding outside the injection mold is carried out by means of molding means independent of the injection mold. - 11 - Method according to one or more of claims 1 to 4, characterized in that the deformation of the molding outside the injection mold is carried out with the use of molding means associated with the injection mold to which a different position is placed outside the injection mold 5 for deforming the object. given. 7. A method according to any one of claims 1 to 6, characterized in that the deforming means independent of the injection mold and the forming means associated with the injection mold are combined to deform the object. Method according to one or more of claims 2 to 7, characterized in that the formation of the objects produced independently of the molding is carried out by injection molding thermopiastes against a part of the molding. Method according to claim 8, characterized in that thermoplastic, rubber-like materials are used. 10. Apparatus for carrying out the method according to one or more of claims 1 to 9, comprising an injection mold with an associated part for lifting a molded object out of the mold and feeding this object to a processing station, with characterized in that the part co-operating with the injection mold is a transport member which remains during the injection molding in the closed mold and after pressing presses the molding from the mold to a post-molding station and then to a discharge station. 1 8203001 Device according to claim 10, characterized in that the transport member runs through a closed path. - 12 - 12. Device as claimed in claims 10 and 11, characterized in that the conveying element is of multiple design and the components carrying the molding are positioned such that during the injection molding in the closed mold a previous molding is located in the post-molding station. 13. Device as claimed in claims 10-12, characterized in that the supporting components are molding schools or engravings, which are removable from the injection mold and fit precisely into carriers of molded parts in the finishing station. 14. Device as claimed in claims 10-13, characterized in that the forming means are stamps, which can perform a movement relative to the engraving placed in the finishing station. 15. Device as claimed in claims 10-14, characterized in that the post-processing station is provided with means for successively oriented feeding of one or more objects manufactured independently of the molding. Device according to one or more of claims 10 to 15, characterized in that the finishing station comprises one or 20 more injection molding machines and the supporting components fit into a second injection mold and form a whole therewith. Device according to claim 16, characterized in that the molding encloses a new mold cavity together with at least the second injection mold. 18. Device as claimed in claims 16 and 17, characterized in that at the location of the mold cavity in the second injection mold, the wall of the molding closes a second space in the mold at the distance away from the mold cavity. side of the wall in which space part of the molding fits after deformation. 19. Device as claimed in claims 10-18, characterized in that the carriers for the object go through a cooling path from the post-processing station to a delivery station. 20, Molding, in particular a pipe fitting, made of plastic, by the method according to one or more of claims 1-6, characterized in that it is provided with one or more objects which have been molded by post-molding. fixed. 8203001