Adaptor plate and injection molding machine having such an adaptor plate

Abstract

The present invention concerns an adaptor plate for connecting a cover plate to a plurality of piston housings of an injection molding machine, wherein the adaptor plate has a first fluid passage and a second fluid passage for feeding a first and a second control fluid into the piston housings, wherein the first fluid passage has at least one first fluid passage inlet for receiving the first control fluid and a plurality of first fluid passage outlets for discharge of the first control fluid to the piston housings and the second fluid passage has at least one second fluid passage inlet for receiving the second control fluid and a plurality of second fluid passage outlets for discharge of the second control fluid to the piston housings.

Claims

1. An adaptor plate for connecting a cover plate to a plurality of piston housings of an injection molding machine, wherein the adaptor plate has a first fluid passage for feeding a first control fluid into the piston housings and a second fluid passage for feeding a second control fluid into the piston housings, wherein the first fluid passage has at least one first fluid passage inlet for receiving the first control fluid and a plurality of first fluid passage outlets for discharge of the first control fluid to the piston housings and the second fluid passage has at least one second fluid passage inlet for receiving the second control fluid and a plurality of second fluid passage outlets for discharge of the second control fluid to the piston housings.

2. An adaptor plate as set forth in claim 1, wherein the plate has an upper surface, a lower surface and a peripherally extending edge surface connecting the upper surface to the lower surface, and wherein the plurality of the first fluid passage outlets and the plurality of the second fluid passage outlets are arranged on the lower surface.

3. An adaptor plate as set forth in claim 1, wherein the cross-section of the first fluid passage inlet differs from the cross-sections of the first fluid passage outlets.

4. An adaptor plate as set forth in claim 1, wherein the adaptor plate comprises at least two plate-shaped elements which are arranged in mutually superposed relationship and comprise differing material, wherein the material from which the one plate-shaped element is made has a lower degree of thermal conductivity than the material from which the other plate-shaped element is made.

5. An adaptor plate as set forth in claim 1, wherein the adaptor plate comprises at least two adaptor plate segments, wherein each of the at least two adaptor plate segments has at least one fluid passage outlet and at least one fluid passage extends over the at least two adaptor plate segments.

6. An adaptor plate as set forth in claim 1, wherein the adaptor plate has a through opening for receiving a sprue passage of an injection molding machine.

7. An adaptor plate as set forth in claim 1, wherein there is provided a third fluid passage for carrying a temperature-control fluid.

8. A module system comprising: an adaptor plate as set forth in claim 1; a plurality of piston housings in which a respective piston connected to a closure needle is arranged; a hot runner distributor plate in which a hot runner is arranged; and a plurality of nozzle housings which are so arranged that by a movement of one of the pistons the closure needle connected to said piston selectively opens or closes an opening in the nozzle housing.

9. An injection molding machine comprising: a hot runner for feeding a plasticized molten material into a plurality of molds; a plurality of closure needles for selectively closing or opening the hot runner, wherein each closure needle has a piston which is connected thereto and which is disposed in a piston housing having an opening and subdivides the housing into a first and a second chamber; an adaptor plate as set forth in claim 1; and a cover plate, wherein the piston housing has a first fluid inlet communicating with the first chamber and a second fluid inlet communicating with the second chamber, which are so arranged that fluid can be transferred by way of the first fluid outlet of the adaptor plate into the first fluid inlet of the piston housing and fluid can be transferred by way of the second fluid outlet of the cover plate into the second fluid inlet of the piston housing so that the piston can be acted upon with fluid on both sides, wherein the cover plate has a first and a second fluid outlet, and wherein the first fluid outlet of the cover plate is connected to the first fluid inlet of the adaptor plate and the second fluid outlet of the cover plate is connected to the second fluid outlet of the adaptor plate.

10. An injection molding machine as set forth in claim 9, wherein the hot runner is arranged in a hot runner distributor plate and the adaptor plate is fixed to the hot runner distributor plate.

11. An injection molding machine as set forth in claim 9, wherein the adaptor plate is connected in positively locking relationship to the cover plate in all directions perpendicularly to the closure needle axes but a relative movement is possible in the direction of the closure needle axes.

12. An injection molding machine as set forth in claim 10, wherein each closure needle is guided by one of the piston housings through the hot runner distributor plate into a nozzle housing which has an opening closable by the closure needle, and wherein a spring element is arranged between the nozzle housing and the cover plate.

13. An injection molding machine as set forth in claim 10, wherein a spring element is arranged between cover plate and adaptor element or between the piston housing and the hotrunner distribution plate.

14. An injection molding machine as set forth in claim 9, wherein the piston housing and/or the adaptor plate has/have a first circular groove in which a first O-ring is arranged, wherein the first O-ring seals off the first fluid inlet of the piston housing with respect to the second fluid inlet of the piston housing, wherein the piston housing and/or the adaptor plate has/have a second circular groove in which a second O-ring is arranged, and wherein the first fluid inlet of the piston housing is arranged between the first and second O-rings.

15. An injection molding machine comprising: a cover plate; a hot runner plate having a plurality of openings for receiving nozzle housings; and a plurality of module systems as set forth in claim 8, wherein the plurality of module systems are secured to the hot runner plate.

16. An adaptor plate as set forth in claim 2, wherein the first fluid passage inlet and the second fluid passage inlet are arranged on the upper surface.

17. An adaptor plate as set forth in claim 3, wherein the cross-section of the second fluid passage inlet differs from the cross-sections of the second fluid passage outlets.

18. An adaptor plate as set forth in claim 4, wherein the fluid passage outlets are arranged in the plate-shaped element made from the material with the higher level of thermal conductivity.

19. An adaptor plate as set forth in claim 2, wherein the cross-section of the first fluid passage inlet differs from the cross-sections of the first fluid passage outlets, wherein the adaptor plate comprises at least two plate-shaped elements which are arranged in mutually superposed relationship and comprise differing material, wherein the material from which the one plate-shaped element is made has a lower degree of thermal conductivity than the material from which the other plate-shaped element is made, and wherein the fluid passage outlets are arranged in the plate-shaped element made from the material with the higher level of thermal conductivity.

Description

[0034] Further advantages, features and possible uses of the present invention will be clearly apparent from the description hereinafter of some embodiments and the accompanying Figures in which:

[0035] FIG. 1 shows a cross-sectional view of a first embodiment according to the invention of the injection molding machine,

[0036] FIG. 2 shows a perspective exploded view of the injection molding machine of FIG. 1,

[0037] FIG. 3 shows a perspective view of a module system of a second embodiment of the invention,

[0038] FIG. 4 shows a cross-sectional of the module of FIG. 3,

[0039] FIG. 5 shows a perspective exploded view of a third embodiment of the invention, and

[0040] FIG. 6 shows a sectional view of the embodiment of FIG. 5.

[0041] FIG. 1 shows an injection molding machine according to the invention. That machine has a hot runner plate 3 and a cover plate 2 resting thereon, the plates being screwed together by means of the screws 4. The cover plate 2 and the hot runner plate 3 form a cavity in which an adaptor plate 5, a plurality of piston housings 6, a hot runner distributor plate 8 and a plurality of nozzle housings 10 are arranged. The nozzle housings 10 extend through openings in the hot runner plate 3.

[0042] The illustrated injection molding machine 1 can be used to produce corresponding moldings like for example PET preforms. The corresponding mold cavities are disposed for that purpose beneath the nozzle housings 10.

[0043] Arranged in the piston housing 6 is a piston 12 which can reciprocate within the housing and subdivides the housing into two chambers 19 and 20. Connected to the piston 12 is a closure needle 7 which extends from the piston housing through the hot runner distributor plate 8 by way of the nozzle housing 10 as far as the opening 11 in the nozzle housing 10. Arranged in the hot runner distributor plate 8 is a part of the hot runner 9 which in operation is filled with heated plasticized molten material. If now the piston 12 is moved upwardly the closure needle 7 also moves upwardly and opens the opening 11 in the nozzle housing 10 so that molten material can be discharged from the opening 11 into provided mold cavities.

[0044] In order to move the piston 12 the chambers 19 and 20 are acted upon selectively with a control fluid, for example air. For that purpose the piston housing 6 has a first fluid inlet 15 connected to the upper chamber 19 and a second fluid inlet 16 connected to the lower chamber 20. The feed of control fluid into the piston housings 6 is effected by way of the adaptor plate 5 which extends over a plurality of piston housings 6. The adaptor plate 5 has a first fluid outlet 13 and a second fluid outlet 14 which are in communication with the fluid inlets of the piston housing 6. O-rings 18 and 17 which are introduced into corresponding circular grooves are provided for sealing off the fluid passages relative to each other and relative to the exterior.

[0045] FIG. 2 shows an exploded view of the injection molding machine of FIG. 1. It will be seen here that the hot runner distributor plate 8 has in total 16 nozzle housings 10 and correspondingly 16 piston housings 6 which are grouped around the sprue tube 21. Plasticized molten material can be transferred into the hot runner distributor plate 8 by way of the sprue tube 21. As an alternative thereto the plasticized molten material could be supplied laterally so that it is possible to dispense with the vertical sprue tube.

[0046] The adaptor plate 5 has a through opening 22 through which the sprue tube 21 is passed. The illustrated adaptor plate 5 in the illustrated example therefore closes all 16 piston housings 6. In this example the adaptor plate has two first fluid passages 23, 24 connected to the first fluid inlet 13 and two second fluid inlets 25, 26 connected to the second fluid outlet 14. The fluid inlets 23, 26 supply control fluid to the eight piston housings arranged at the front in FIG. 2 while the first and second fluid inlets 24, 25 supply control fluid to the piston housings shown at the back.

[0047] The adaptor plate 5 is screwed to the hot runner distributor plate 8 by means of the screws 28. The pins 27 which engage into corresponding bores both in the cover plate 2 and also in the adaptor plate 5 provide for sealing integrity of the adaptor plate relative to the cover plate in the plane of the adaptor plate 5, in which respect however relative movement as between the adaptor plate 5 and the cover plate 2 is possible to a limited extent by virtue of the pin connection by means of the pins 27.

[0048] The adaptor plate 5 together with the hot runner distributor plate 8, the piston housings 6, the nozzle housings 10 and the sprue tube 21 forms a module system which can be provided when already pre-assembled. When equipping the hot runner plate 3 with the corresponding nozzles it is then possible to access the module.

[0049] FIG. 3 shows an exploded view of such a module in a second embodiment.

[0050] Insofar as possible identical references have been used for identical components. In the second embodiment the adaptor plate 5 is made from two segments 5 and 5. The two segments 5 and 5 are of differing thickness. In principle however the segments can also be of the same thickness. The use of segments of differing thicknesses permits the use of piston housings 6 and 6 which are built up to differing heights. It will be seen from FIG. 3 that, besides the piston housings 6 known from FIG. 2, flatter piston housings 6 have also been used in part here. In order nonetheless to securely mount those piston housings between the cover plate 2 and the hot runner plate 3 the adaptor plate 5 must compensate for the difference in height so that the adaptor plate has the segment 5.

[0051] That will be clear from the corresponding sectional view in FIG. 4. It will be clearly seen here that piston housings 6 of smaller height and piston housings 6 of greater height have been used. Both configurations of the piston housings 6, 6 can be used within an injection molding machine, by virtue of the segmented configuration of the adaptor plate 5 with the segments 5 and 5 of differing thickness.

[0052] FIGS. 5 and 6 show a third embodiment of the invention in which the adaptor plate 5 comprises two portions 5 and 5 which rest upon each other in a sandwich-like structure. Here the element 5 is made from a different material from the element 5, more specifically a material of lower thermal conductivity in order to ensure heat insulation between the temperature-controlled hot runner distributor 8 and the generally cooled cover plate 2. Separate cooling of the cover plate 2 can be eliminated under some circumstances by the provision of a suitably divided cover plate with heat insulation. At any event however a lower through-flow of coolant is necessary as less heat energy is transmitted by way of the piston housings.

LIST OF REFERENCES

[0053] 2 cover plate

[0054] 3 hot runner plate

[0055] 4 screws

[0056] 5 adaptor plate

[0057] 5, 5 segments

[0058] 5, 5 parts of the adaptor plate

[0059] 6, 6 piston housing

[0060] 7 closure needle

[0061] 8 hot runner distributor plate

[0062] 9 hot runner

[0063] 10 nozzle housing

[0064] 11 opening

[0065] 12 piston

[0066] 13, 15 first fluid inlet

[0067] 14, 16 second fluid outlet

[0068] 17, 18 O-ring

[0069] 19, 20 chamber

[0070] 21 sprue tube

[0071] 22 through opening

[0072] 23, 24 first fluid passage

[0073] 25, 26 second fluid passage

[0074] 27 pins

[0075] 28 screws