SYSTEM FOR THE FURTHER TREATMENT OF PREFORMS PRODUCED BY MEANS OF INJECTION MOLDING

Abstract

The present invention concerns a system for the further treatment of hollow body preforms produced by injection molding, comprising i) a receiving plate having at least one receiving cavity for receiving a preform, ii) a post-treatment system which has a) a post-treatment plate, b) at least one impression pin provided for changing the internal contour of the profile by either coming into contact with the inside of the preform during the post-treatment or closing the preform and acting on the inside space with a fluid under pressure, whereby the preform is inflated, and c) at least one post-treatment element which is provided for passing into the interior of a preform received in the receiving cavity or coming into contact with the preform, and iii) a movement device with which the receiving plate can be reciprocated relative to the post-treatment plate between a first position in which the impression pin is positioned within the receiving cavity, a second position in which the post-treatment element is positioned within the receiving cavity or comes into contact with a preform received therein, and a third position in which neither the impression pin nor the post-treatment element is positioned within the receiving cavity or comes into contact with a preform received therein.

Claims

1. A system for the further treatment of hollow body preforms produced by injection molding, comprising i) a receiving plate having at least one receiving cavity for receiving a preform, ii) a post-treatment system which has a) a post-treatment plate, b) at least one impression pin provided for changing the internal contour of the profile by either coming into contact with the inside of the preform during the post-treatment or closing the preform and acting on the inside space with a fluid under pressure, whereby the preform is inflated, and c) at least one post-treatment element which is provided for passing into the interior of a preform received in the receiving cavity or coming into contact with the preform, and iii) a movement device with which the receiving plate can be reciprocated relative to the post-treatment plate between a first position in which the impression pin is positioned within the receiving cavity, a second position in which the post-treatment element is positioned within the receiving cavity or comes into contact with a preform received therein, and a third position in which neither the impression pin nor the post-treatment element is positioned within the receiving cavity or comes into contact with a preform received therein.

2. A system as set forth in claim 1 characterised in that the posttreatment element is an ejection element having a holding device for selectively holding a preform.

3. A system as set forth in claim 1 characterised in that the posttreatment element is a post-treatment pin having a fluid passage through which fluid can be introduced into or sucked out of the interior of a preform received in the receiving cavity.

4. A system as set forth in claim 1 characterised in that the impression pin has a sealing element which can come into contact with the opening of the hollow body preform and seal same off and a fluid feed for introducing a fluid under pressure into the hollow body preform.

5. A system as set forth in claim 1 characterised in that the impression pin is moveable relative to the post-treatment plate.

6. A system as set forth in claim 1 characterised in that the receiving plate has at least two groups of receiving cavities, wherein each group has a plurality of receiving elements, and the groups are arranged at a spacing a from each other.

7. A system as set forth in claim 6 characterised in that the device for moving the receiving plate is so adapted that it can move the receiving plate into at least two different positions, the first removal position and a second removal position, between two opened tool halves, which are spaced from each other at the spacing a.

8. A system as set forth in claim 6 characterised in that the device for moving the receiving plate is so adapted that it can move the receiving plate into at least two different positions, the first post-treatment position and the second post-treatment position, outside the tool halves, which are spaced at the spacing a from each other.

9. A system as set forth in claim 6 characterised in that the post-treatment system has a group of impression pins and a group of post-treatment elements which are spaced from each at a spacing a, which are so adapted that in the first position the impression pins are positioned within the first group of receiving cavities and the posttreatment elements are positioned within the second group of receiving cavities or come into contact with preforms received therein, and in the second position the impression pins are positioned within the second group of receiving cavities and the post-treatment elements are positioned within the first group of receiving cavities or come into contact with preforms received therein.

10. A system as set forth in claim 9 characterised in that the posttreatment system has at least one further group of post-treatment elements, wherein the one group of post-treatment elements is formed by ejection elements and the other group of post-treatment elements is formed by post-treatment pins with fluid passage.

11. A system as set forth in claim 1 characterised in that the post-treatment plate has an impression plate moveable relative to the post-treatment plate, wherein the impression pin or the group of impression pins is fixed to the impression plate.

12. A system as set forth in claim 1 characterised in that the impression pin or the group of impression pins has one or more openings for the feed of fluid into the interior of the preform, wherein the 25 impression pin has a sealing element which is so adapted that when the impression pin is arranged within the preform it can seal off the preform so that an increased pressure can be produced in the interior of the preform by the feed of fluid.

13. A system as set forth in claim 1 characterised in that there is provided a locking device which in an activated condition provides a positively locking connection between the receiving plate and the post-treatment plate in the first and second positions, which has to be deactivated if the receiving plate is to be moved relative to the posttreatment plate into the third position.

14. A system for the further treatment of hollow body preforms produced by means of injection molding, comprising i) a receiving plate having at least one receiving cavity for receiving a preform, ii) a post-treatment system having at least one impression pin which is provided for changing the internal contour of the preform by either coming into contact with the inside of the preform during the posttreatment or closing the preform, and acting on the inside space with a fluid under pressure, whereby the preform is expanded, iii) a movement device with which the receiving plate can be reciprocated relative to the post-treatment plate between a contact position in which the impression pin is positioned within the receiving cavity and a readiness position in which the impression pin is positioned outside the receiving cavity, and iv) a locking device which in an activated condition provides a positively locking connection between the receiving plate and the posttreatment plate in the contact position, which must be deactivated if the receiving plate is to be moved relative to the post-treatment plate into the readiness position.

15. An injection molding system having a mold tool comprising two tool halves, wherein the one tool half has a multiplicity of cavities and the other tool half has a multiplicity of cores, and a further treatment system as set forth in claim 1.

16. An injection molding system as set forth in claim 1 characterised in that the receiving cavities are larger at least in the bottom region than the cavities of the mold tool.

17. An injection molding system as set forth in claim 15 characterised in that the post-treatment plate is connected to a tool half, wherein the post-treatment plate is preferably connected to the tool half which has the multiplicity of cores.

18. A system as set forth in claim 11 wherein the post-treatment plate and the impression plate are connected together by way of a column guide means.

19. A system as set forth in claim 18 wherein the impression pin or the group of impression pins extends through one or more openings in the post-treatment plate.

20. An injection molding system having a mold tool comprising two tool halves, wherein the one tool half has a multiplicity of cavities and the other tool half has a multiplicity of cores, and a further treatment system as set forth in claim 14.

Description

[0060] Further advantages, features and possible uses of the present invention will be apparent from the description hereinafter of a preferred embodiment. In the drawing:

[0061] FIG. 1 shows a diagrammatic view of a PET injection molding system with post-treatment unit, and

[0062] FIG. 2 shows a sectional view of a first embodiment according to the invention.

[0063] FIG. 1 shows a diagrammatic view of a PET injection molding system with post-treatment unit. The injection molding mold comprises two plates 1, 2 which are moveable relative to each other, wherein one plate 1 is stationary and one plate 2 is moveable in the illustrated embodiment.

[0064] The one plate has cores 3 while the other plate has corresponding cavities (not shown). The two plates can be moved relative to each other from an open position shown in FIG. 1 into a closed position in which the cores 3 of the moveable plate 2 are arranged in the corresponding cavities of the stationary plate 1. Between the cavities of the stationary plate 1 and the cores 3 of the moveable plate 2 the so-called mold cavity is then formed, being filled with plasticized PET, to constitute a preform.

[0065] As soon as the outer surfaces of the preform are cooled, that is to say have set, the mold is opened and a removal element 4 in the form of a plate is moved between the opened plates 1, 2. The preforms sitting on the cores 3 of the moving plate are then transferred into corresponding receiving elements which are also in the form of cavities.

[0066] In the illustrated example the injection molding tool has six cores, that is to say six preforms are produced in the injection molding cycle. The corresponding removal element 4 however has 18 (36) receiving elements 5 which can each receive a respective preform. The removal element 4 thus has three groups of receiving cavities which are successively fitted with corresponding preforms. As soon as the preforms have been transferred from the cores 3 on to the receiving elements 5 of the removal element 4 the removal element 4 is moved into the position shown in FIG. 1 again and the injection molding mold consisting of the two plates 1, 2 can be closed again. As in the illustrated embodiment the removal element is connected to the stationary plate 1 the post-treatment element 6 connected to the moving plate 2 moves towards the removal element 4. The post-treatment element 6 has a row of post-treatment pins 7 which, while the mold is closed, engage into the preforms held in the removal element 4.

[0067] The individual post-treatment pins are mounted on a pin plate. In addition transfer elements 8 or ejection elements are fixed to the pin plate, which serve for the transfer of the post-treated preforms from the receiving plate 4 on to the transfer elements 8 or the post-treatment element 6 respectively. Fixed to the post-treatment element 6 is a blower 27 which can produce increased pressure or reduced pressure in a pressure chamber 26. The entire post-treatment plate 6 is designed to be rotatable about the shaft 12 so that the post-treatment element can be rotated through 90 so that the preforms seated on the transfer element 8 can be ejected by the force of gravity.

[0068] It will be seen that the post-treatment element 6 has more pins than the receiving plate 4 has receiving cavities. The receiving plate can therefore be positioned in a plurality of different positions (in the illustrated example three) relative to the post-treatment element 6. The corresponding positions are adopted in succession, after a new respective group of preforms has been removed from the injection molding mold, so that the preform group held longest in the receiving plate 4 is respectively positioned with respect to the transfer elements 8 and can therefore be removed.

[0069] FIG. 2 shows a sectional view of an embodiment of the invention. Here, a transfer or ejection element 8 as well as a post-treatment element 7 is also shown at the pin plate 6. In addition the pin plate 6 here has an impression pin 10. FIG. 2 also shows the receiving element 5 which is cooled by way of the cooling passages 22, involving spiral passages. Compressed air or vacuum can be selectively supplied at the bottom of the receiving element 5 by way of the feed conduit 23 in order to either hold the preform 9 within the receiving cavity 5 or to eject it therefrom. The post-treatment pin 7 is concentrically surrounded by a sleeve 11, by way of which cooling air is passed into the interior of the preform, being discharged inter alia by way of the tip 19 of the post-treatment pin. There are also cooling passages 22, by means of which the post-treatment plate can be cooled, preferably being water-cooled.

[0070] In addition the receiving cavities 5 of the post-treatment plate in the illustrated embodiment, opposite the receiving opening by way of which a preform is inserted, have a fluid passage arranged on the central axis of the receiving cavity 5. Positioned in the fluid passage is a support element 20 with a support surface which, in the condition of being inserted into the receiving cavity, comes into contact therewith at least after processing with the impression pin.

[0071] During the post-treatment operation therefore the impression pin 10, the post-treatment pin 7 and the transfer element 8 are successively introduced into each preform. In that case the impression pin 10 serves to stretch at least the bottom region of the preform, that is to say to put it into a shape defined by the bottom of the receiving cavity and the external contour of the contact element 30 which is fixed to the impression pin 10.

LIST OF REFERENCES

[0072] 1, 2 plate

[0073] 3 cores

[0074] 4 removal element

[0075] 5 receiving element

[0076] 6 post-treatment element

[0077] 7 post-treatment pin

[0078] 8 transfer element

[0079] 9 preform

[0080] 10 impression pin

[0081] 11 sleeve

[0082] 12 shaft

[0083] 19 tip

[0084] 20 support element

[0085] 22 cooling passages

[0086] 23 feed means

[0087] 30 contact element