Compact post-mold cooling device and method for thermally conditioning molded articles

• US 6,139,789 A
• Filed: 04/20/1999
• Issued: 10/31/2000
• Est. Priority Date: 07/31/1998
• Status: Expired due to Fees

• Current Assignee: Husky Injection Molding Systems Limited
• Original Assignee: Husky Injection Molding Systems Limited
• Inventors: Neter, Witold, Olaru, Gheorghe, Oueslati, Faisal
• Primary Examiner(s): DAVIS, ROBERT B
• Application Number:
  US09/294,568
• Time in Patent Office: 560 Days
• Field of Search: 264/328.14, 264/458, 264/535, 264/537, 264/237, 425/174.4, 425/526, 425/532, 425/534, 425/547
• US Class Current: 264/535
• CPC Class Codes: B29C 2035/1658 using gas
• CPC Class Codes: B29C 2049/023 using inherent heat of the preform, i.e. 1 step blow moulding
• CPC Class Codes: B29C 2949/0715 the preform having one end closed
• CPC Class Codes: B29C 2949/3008 at neck portion
• CPC Class Codes: B29C 2949/3012 at flange portion
• CPC Class Codes: B29C 2949/3016 at body portion
• CPC Class Codes: B29C 2949/302 at bottom portion
• CPC Class Codes: B29C 2949/3028 having three or more components
• CPC Class Codes: B29C 2949/3036 having three or more components being injected
• CPC Class Codes: B29C 35/16 Cooling cooling extruded material B29C48/911; cooling preforms for blow moulding B29C49/6427; cooling blown articles B29C49/66; cooling tyres during post cure inflation B29D30/0643
• CPC Class Codes: B29C 45/7207 of the moulded articles
• CPC Class Codes: B29C 49/06 Injection blow-moulding
• CPC Class Codes: B29C 49/6409 Thermal conditioning of preforms B29C49/68 takes precedence
• CPC Class Codes: B29C 49/6427 Cooling of preforms
• CPC Class Codes: B29C 49/648 of preforms or parisons
• CPC Class Codes: B29K 2105/253 Preform

Abstract

The present invention relates to a multi-stage, post-mold cooling method and apparatus used in conjunction with an injection molding machine having an aggressive cycle time and a high output. The apparatus of the present invention includes a thermal conditioning device/station with cooling tubes for keeping separate the preforms of each batch and effecting cooling of the molded preforms, several separated cooling levels for simultaneously cooling multiple batches of preforms, and internal devices for automatically transferring each batch of molded preforms from one cooling level to the next. In a preferred embodiment, the thermal aconditioning device/station is partially sealed to create a controlled temperature environment for conditioning the molded articles. In another embodiment, the thermal conditioning device/station includes a level for re-heating the preforms.

Claims

1. A method for thermally conditioning molded articles outside of a mold comprising the steps of:

forming a plurality of molded articles in a molding machine;

removing said molded articles from said molding machine while said articles are warm and not fully solidified;

providing a thermal conditioning station having at least two internal thermal conditioning levels, said thermal conditioning station comprising a plurality of tubes having a plurality of levels and internal means for automatically transferring molded articles in said tubes from one level to a next level;

transferring said molded articles to a first level of said thermal conditioning station, said transferring step including placing an individual one of said molded articles into a respective one of said tubes; and

thermally conditioning said molded articles within said first level of said thermal conditioning station to improve the quality of the molded articles without increasing mold cycle time by subjecting said molded articles to at least one convective thermal treatment.

2. The method according to claim 1, wherein said thermal conditioning step comprises convectively cooling exterior surfaces of said molded articles.

3. The method according to claim 2, wherein said thermal conditioning step further comprises heating said molded articles after said convective cooling step.

4. The method according to claim 1, wherein said thermal conditioning step comprises heating said molded articles while in said thermal conditioning station.

5. The method according to claim 1, further comprising:

separating said molded articles from each other prior to transferring said molded articles to said first level; and

said thermal conditioning step comprising simultaneously subjecting said molded articles within said first level to a convective cooling treatment.

6. The method according to claim 1, further comprising:

said forming step comprising forming a first batch of molded articles;

separating said molded articles in said first batch; and

said thermal conditioning step comprising simultaneously subjecting said molded articles in said first batch to a first convective cooling treatment at said first level within said thermal conditioning station.

7. The method according to claim 6, further comprising:

forming a second batch of molded articles;

separating said molded articles in said second batch; and

said thermal conditioning step comprising simultaneously subjecting said molded articles in said second batch to said first convective cooling treatment at said first level and said molded articles in said first batch to a second convective cooling treatment at a second level within said thermal conditioning station.

8. The method according to claim 7, further comprising:

forming a third batch of molded articles;

separating said molded articles in said third batch; and

said thermal conditioning step comprising simultaneously subjecting said molded articles in said third batch to said first convective cooling treatment at said first level, said molded articles in said second batch to said second convective cooling treatment at said second level, and said molded articles in said first batch to a heat treatment at a third level within said thermal conditioning station.

9. The method according to claim 1, wherein:

said removing step comprises providing a take-out plate for removing said molded articles from said molding machine and positioning said take-out plate between mold core and mold cavity portions of said molding machine to receive said molded articles; and

said transferring step comprises moving said take-out plate to a position adjacent said molding machine and rotating said take-out plate to align it with an inlet to said thermal conditioning station.

10. The method according to claim 1, wherein:

said molding machine includes a rotary turret core plate device having a plurality of core plates;

said forming step comprises moving a first one of said core plates into a mold closed position with a mold cavity portion;

said removing step comprises moving said first one of said core plates relative to said mold cavity portion so as to withdraw said plurality of molded articles; and

said transferring step comprises rotating said rotary turret core plate device until said first one of said core plates is aligned with an inlet of said thermal conditioning station and ejecting said molded articles from said first one of said core plates.

11. The method according to claim 1, further comprising cooling said molded articles prior to transferring said molded articles to said thermal conditioning station.

12. The method according to claim 11, wherein:

said cooling step comprises placing said molded articles on a cooling frame having a plurality of cooling cores and cooling said molded articles on said cooling cores; and

said transferring step comprises moving said cooling frame to a position where it is aligned with said thermal conditioning station and ejecting said cooling molded articles from said cooling frame.

13. The method according to claim 1, further comprising:

said thermal conditioning step comprising subjecting each said molded article to a flow of cooling air for a first period of time while each said molded article is positioned at said first level in said tubes.

14. The method according to claim 13, further comprising:

actuating said internal means so as to allow each said molded article to freely drop to a second level in each said tube; and

said thermal conditioning step further comprising subjecting each said molded article to a flow of cooling air for a second period of time while each said molded article is positioned at said second level.

15. The method according to claim 14, wherein said second period of time is different from said first period of time.

16. The method according to claim 14, further comprising:

activating said internal means to allow each said molded article in said tubes to freely drop to a third level; and

said thermal conditioning step further comprising subjecting each said molded article to a heat treatment while at said third level.

17. The method according to claim 16, further comprising ejecting said molded articles from said thermal conditioning station after said thermal conditioning step has been completed and conveying said molded articles to a desired location.

18. A thermal conditioning station for thermally treating molded articles comprising:

means for keeping separate different batches of said molded articles;

said keeping means comprises a plurality of columnar tubes;

internal means for holding said molded articles in respective ones of said batches at different levels in said station; and

means for simultaneously thermally treating said molded articles in said batches.

19. The thermal conditioning station of claim 18, further comprising:

said plurality of columnar tubes each being formed by a plurality of aligned tube elements;

each said tube element having an inlet and an outlet;

said internal holding means comprising a shutter plate positioned between adjacent ones of said aligned tube elements;

said shutter plate having at least one opening therein for cooperating with the outlet of at least one of said tube elements; and

means for moving the shutter plate between a first position wherein said shutter plate blocks the outlet said at least one tube element and thereby holds a respective one of said molded articles in said at least one tube element at a first level and a second position where said at least one opening is aligned with the outlet of said at least one tube element to allow said molded article in said at least one tube element to freely drop to a second level in said station.

20. The thermal conditioning station of claim 19, wherein the thermal station is modular in nature and said columnar tubes are arranged in a plurality of rows.

21. The thermal conditioning station of claim 19, further comprising means for convectively cooling said molded articles while said molded articles are at different ones of said levels within said station.

22. The thermal conditioning station of claim 21, wherein each said tube element has at least one opening in a sidewall through which a cooling gas could flow and wherein said station has means for causing a flow of cooling gas in selected ones of said tube elements.

23. The thermal conditioning station of claim 22, further comprising:

a housing surrounding said tubes, said housing having an opening in a sidewall; and

said means for causing a flow of cooling gas comprises fan means positioned outside of said housing for causing a flow of air through said opening in said housing sidewall.

24. The thermal conditioning station of claim 19, further comprising:

said tubes being aligned in at least one row;

each said tube being formed by three separate and aligned tube elements; and

at least two shutter plates associated with each said tube in said at least one row with a first one of said shutter plates being positioned between a first one and a second one of said tube elements of each said tube in said at least one row and a second one of said shutter plates being positioned between said second tube element and a third tube element of each said tube in said at least one row.

25. The thermal conditioning station of claim 24, further comprising means for actuating each said shutter plate so as to automatically transfer each said molded article in each said tube from one level to the next.

26. The thermal conditioning station of claim 24, further comprising a third shutter plate located adjacent an outlet of each said third tube element.

27. The thermal conditioning station of claim 24, further comprising means for heating a molded article located within said third tube element.

28. The thermal conditioning station of claim 27, further comprising a wall having thermal insulating located between said level where said heating occurs and an adjacent level where cooling occurs.

29. The thermal conditioning station of claim 19, further comprising an extensible and retractable tube element movable relative to each said tube element for capturing a molded article to be thermally treated.

30. The thermal conditioning station of claim 18, wherein said internal holding means comprises a retainer at each level where said molded article is to be subjected to a thermal treatment.

31. The thermal conditioning station of claim 30, wherein each said retainer comprises axially movable collars for gripping portions of said molded article.

32. The thermal conditioning station of claim 18, further comprising an array of guide tubes for guiding said molded articles into said station.

33. The thermal conditioning station of claim 32, further comprising:

said guide tube array having a plurality of outlets; and

a shutter plate positioned between each said outlet of said guide tube array and an inlet of said station, said shutter plate being movable between a first position where it blocks entry of said molded articles into said station and a second position where it allows entry of said molded articles into said station.

34. An apparatus for thermally conditioning molded articles outside of a molding machine comprising:

means for removing said molded articles from said molding machine while said articles are warm and not fully solidified;

a thermal conditioning station external to said molding machine, said thermal conditioning station including at least two internal thermal conditioning levels;

means for transferring said molded articles to said thermal conditioning station;

said thermal conditioning station having means for subjecting said molded articles to at least one thermal conditioning treatment at a first one of said internal levels to improve the quality of the molded articles without increasing the mold cycle time of the molded machine; and

said thermal conditioning station comprising a plurality of tubes for receiving said molded articles and internal means associated with each tube for holding a molded article therein at said first one of said levels and subsequently at a second one of said levels.

35. The apparatus of claim 34, wherein said subjecting means comprises means for convectively cooling exterior surfaces of said molded articles at said first one of said levels.

36. The apparatus of claim 35, wherein said subjecting means further comprises means for heating said molded articles after cooling.

37. The apparatus of claim 34, wherein said subjecting means comprises means for heating said molded articles while said molded articles are resident in said thermal conditioning station.

38. The apparatus of claim 34, wherein said removing and transferring means comprises a take-out plate for receiving molded articles from said molding machine while they are still warm.

39. The apparatus of claim 38, wherein said transferring means further comprises a rotatable frame having a plurality of cooling cores on a plurality of faces, said cooling cores mating with said take-out plate to receive said molded articles and said frame rotating so that cooled molded articles may be dispensed into said thermal conditioning station.

40. The apparatus of claim 34, wherein said plurality of tubes keeps molded articles in a batch separate from each other while said molded articles undergo said at least one thermal conditioning treatment.

41. The apparatus of claim 40, wherein said transferring means further comprises an array of guide tubes having outlets aligned with inlets to said tubes.

42. The apparatus of claim 34, wherein:

said molding machine has a rotary turret core plate device with a plurality of core faces which mate with a cavity portion of said machine;

said removing means comprises means for moving one of said core faces away from said cavity portion; and

said transferring means comprises means for rotating said rotary turret core plate device until said molded articles removed from said machine are aligned with said thermal conditioning station and means for ejecting said molded articles.

43. The apparatus of claim 34, further comprising means for actuating said internal holding means to allow said molded article in each said tube to automatically transfer from said first one of said levels to said second one of said levels.

44. The apparatus of claim 34, further comprising:

each said tube being columnar in nature and being formed from a plurality of aligned tube elements; and

said internal holding means being formed by at least one shutter plate between adjacent ones of said tube elements, each said shutter plate having an opening therein which can b e aligned with an outlet of a first one of said tube elements and an inlet of a second one of said tube elements and being movable between a first position where a solid portion of each said shutter plate holds said molded article at a first one of said levels by blocking said outlet of said first one of said tube elements and a second position where said opening is aligned with said outlet of said first one of said tube elements to allow said molded article to freely transfer to said second one of said levels.

45. The apparatus of claim 44, wherein:

each said tube has three aligned tube elements; and

said internal holding means comprises two shutter plates with a first one of said shutter plates being located intermediate a first one and a second one of said three tube elements and a second one of said shutter plates being located intermediate said second one and a third one of said three tube elements, whereby said shutter plates are actuated to allow a molded article in said tube to be subjected to thermal treatments at three different levels in said station.

46. The apparatus of claim 34, wherein said thermal conditioning station has means for cooling a first batch of molded articles at said first one of said levels and means for simultaneously cooling a second batch of molded articles at said second one of said levels.

47. The apparatus of claim 46, further comprising said thermal conditioning station having means for heating a third batch of molded articles while said first and second batches of molded articles are being cooled.

48. The apparatus of claim 46 wherein said cooling means comprises a plurality of tubes in which said molded articles reside and each said tube having at least one orifice for allowing cooling air to flow around at least one molded carticle within each said tube and means for creating said flow of cooling air.

49. The apparatus of claim 48, wherein said thermal conditioning station includes a housing and said cooling air flow creating means are located external to said housing.