Source: http://www.google.com/patents/US6555041?dq=5787449
Timestamp: 2014-11-29 07:43:40
Document Index: 578528582

Matched Legal Cases: ['art 19', 'art 19', 'art 19', 'art 19', 'art 19', 'art 19', 'art 13', 'art 19', 'art 19']

Patent US6555041 - Method of injection molding a skin layer around a core resin - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA multilayer injection molding machine manufactures a molded product formed of a plurality of layers of resins or colors by press fitting resins from a core layer injection unit and a skin layer injection unit to a cavity party formed by pressing and clamping a moving metal mold to a fixed metal mold...http://www.google.com/patents/US6555041?utm_source=gb-gplus-sharePatent US6555041 - Method of injection molding a skin layer around a core resinAdvanced Patent SearchPublication numberUS6555041 B1Publication typeGrantApplication numberUS 09/547,227Publication dateApr 29, 2003Filing dateApr 11, 2000Priority dateOct 29, 1996Fee statusPaidAlso published asCA2219472A1, CA2219472C, DE19747573A1, DE19747573C2, DE19747573C5, US6074190Publication number09547227, 547227, US 6555041 B1, US 6555041B1, US-B1-6555041, US6555041 B1, US6555041B1InventorsTsutomu Nagaoka, Shoji SatoOriginal AssigneeKabushiki Kaisha Kobe Seiko ShoExport CitationBiBTeX, EndNote, RefManPatent Citations (31), Non-Patent Citations (8), Referenced by (1), Classifications (9), Legal Events (2) External Links: USPTO, USPTO Assignment, EspacenetMethod of injection molding a skin layer around a core resinUS 6555041 B1Abstract A multilayer injection molding machine manufactures a molded product formed of a plurality of layers of resins or colors by press fitting resins from a core layer injection unit and a skin layer injection unit to a cavity party formed by pressing and clamping a moving metal mold to a fixed metal mold fixed to a support member. The multilayer injection molding machine is formed by integrating a connecting device body interposed between the fixed metal mold and the support member so as to support the fixed metal mold to the support member and an injection unit connecting device provided on the connecting device body and having a plurality of resin passages allowing the cavity part to communicate with each injection unit.
What is claimed is: 1. An injection molding method using a multilayer injection molding device for forming an injection molded product having a core layer resin surrounded by a skin layer resin, comprising:
applying injection molding pressure at a first predetermined time to the skin layer resin in a skin layer injection unit to inject the skin layer resin into a cavity formed within a metal mold in the multilayer injection molding machine while blocking a core layer resin passage extending from a core injection unit to the cavity; applying injection molding pressure to the core layer resin in the core injection unit to inject the core layer resin together with the skin layer resin into the cavity after opening the core layer resin passage at a second predetermined time after the first predetermined time; terminating the injection of the core layer resin by removing injection pressure from the core layer resin while continuing to apply injection pressures to the skin layer resin and blocking the core layer resin passage at a third predetermined time after the second predetermined time; and opening the core layer resin passage at a fourth predetermined time following the third predetermined time while applying a holding pressure to the skin layer resin that is less than the skin layer resin injection pressure and of a level causing the skin layer resin to flow back to the core layer resin passage. 2. The injection molding method of claim 1, further comprising:
closing the opening in the core layer passage at a fifth predetermined time following the fourth predetermined time. 3. The injection molding method of claim 1, further comprising:
terminating the holding pressure being applied to the skin resin layer at a sixth predetermined time following the fifth predetermined time. Description
BACKGROUND OF THE INVENTION The present invention relates to a multilayer injection molding machine capable of press fitting resins from a plurality of injection units to a cavity part within a metal mold, respectively, an injection unit connecting device therefor, and an injection molding method thereby.
SUMMARY OF THE INVENTION The present invention involves an injection unit connecting device for a multilayer injection molding machine capable of press fitting resins from a plurality of injection units to a cavity part formed by clamping metal mold, and this injection unit connecting device comprises a connecting device body provided on the metal mold, and a resin passage means provided on the connecting device body and having a plurality of resin passages allowing the cavity part to communicate with each injection unit described above.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged sectional view of the essential part of an injection unit connecting device according to the present invention.
FIG. 5 is a cross-sectional view taken on line A�A of the injection unit connecting device in FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention is described in reference to FIG. 1 to FIG. 5.
On the other side of the male-side laminate member 19 where the skin layer passage 19 b is opened in a plurality of positions, a conical inclined protruding part 19 c is formed. The skin layer passage 19 b is opened in the inclined wall surface of the inclined protruding part 19 c. One end of a core layer passage 19 d is opened in the top part of the inclined protruding part 19 c, and the core layer passage 19 d is formed in such a manner as to be extended in the axial center direction of the male-side laminate member 19 (the inclined protruding part 19 c), then bent at a right angle in the center position between the metal mold connecting board 15 and the fixed board 16, passed between the branched passages of the skin layer passage 19 b, and opened in the side wall surface. A closed passage 19 e is allowed to communicate with the bent part of the core layer passage 19 d, and the closed passage 19 e is formed so as to be opened in the side wall surface opposite to the bending direction of the core layer passage 19 d. The male-side laminate member 19 having the above-mentioned structure is fitted to the female-side laminate member 20. The female-side laminate member 20 pierces through the center part of the metal mold connecting board 15, and one end of the collecting passage 20 a is opened in the fixed mold 9-side end part of the female-side laminate member 20. The collecting passage 20 a is formed in such a manner as to be extended toward the inclined protruding part 19 c, then increased in aperture so as to keep a fixed space with the inclined wall surface of the inclined protruding part 19 c, and blocked by the end surface of the male side laminated member 19. One-side ends of the core layer passage 20 c and the closed passage 20 b are opened to the side wall of the female-side laminate member 20, and the other ends of the core layer passage 20 c and the closed passage 20 b are allowed to communicate with the core layer passage 19 d and closed passage 19 e of the male-side laminate member 19. Thus, the core layer passage 20 c, the core layer passage 19 d after bending, the closed passage 19 e, and the closed passage 20 b are allowed to mutually communicate, whereby a linear through-hole is formed extending from the male-side laminate member 19 to the female-side laminate member 20 in the right-angled direction to the clamping direction.
The skin layer resin flows into the skin layer passage 19 b of the injection unit connecting device 10 through the nozzle part 13 a, and advances while being branched in a plurality of directions in the skin layer passage 19 b. The skin layer resin further advances in the skin layer passage 19 b, whereby it flows out to the clearance between the inclined protruding part 19 d of the male-side laminate member 19 and the collecting passage 20 a of the female-side laminate member 20, and flows toward the fixed mold 9 while perfectly covering the inclined wall surface of the inclined protruding part 19 c. On the other hand, the blocking member 22 a of the passage opening and closing member 22 is retreated when a prescribed waiting time passed after the skin layer resin is discharged, whereby the core layer passage 19 d is laid into the opened state. The core layer resin is filled in the core layer injection unit 12 and heated, and the core layer resin laid into the fused state is discharged. Although the injecting pressure of the core layer resin is set lower than the injecting pressure of the skin layer resin in this embodiment, it is varied depending on molded products, and may have the reverse pressure relation.
In the press fitting of the skin layer resin and the core layer resin, the injection of the core layer resin is terminated prior to the injection of the skin layer resin as shown in FIG. 2, and the core layer passage 19 d is blocked by advancing the blocking member 22 a to the passage opening and closing member 22. Thereafter, the core layer passage 19 d is opened by retreating the blocking member 22 a to the passage opening and closing member 22 in the pressure holding period of the skin layer resin, whereby the skin layer resin present in the collecting passage 20 a is made to flow back to the core layer passages 19 d, 20 c. After the lapse of a time possibly necessary to fill the core layer passages 19 d, 20 c with a sufficient quantity of the skin layer resin, the core layer passage 19 d is blocked by advancing the blocking member 22 a. The skin layer resin and the core layer resin are press fitted in a prescribed quantity unit in this way, and the injection molding machine is slid into waiting state when one injection molding is completed, and repeats a series of operations described above again when the start of the following injection molding is instructed. Since only the skin layer resin is present in the core layer passage 19 d blocked by the blocking member 22 a, press fitting can be performed while surely preventing the inclusion of the core layer resin into the skin layer resin in the initial stage of press fitting in the following injection molding.
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