Injection device and resin injection method

Patent metadata

Field	Value
Publication number	US-10213947-B2
Application number	US-201615134591-A
Country	US
Kind code	B2
Filing date	Apr 21, 2016
Priority date	Nov 25, 2009
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

As an injection screw 2 applies pressure, a holding pressure plunger 22 is moved backward under the pressure of a resin to flow the resin into a holding pressure path 9, and the resin in a resin path 6 is pressurized (primary holding pressure process). A shutoff plunger 12 is closed, and the resin in the resin path 6 and the holding pressure path 9 is pressurized by the holding pressure plunger 22 (secondary holding pressure process). Further, the shutoff plunger 12 is opened, and the holding pressure plunger 22 is moved forward until its tip projects into the resin path 6 to discharge all the resin in the holding pressure path 9 to the resin path 6, whereby the resin beside the injection screw 2 as compared with the shutoff plunger 12 is held with respect to the holding pressure path 9.

First claim

What is claimed is:

1. A resin injection method for injecting a resin from an injection nozzle through a resin path and flowing the resin into a holding pressure path communicating with the resin path to maintain a first pressure of the resin in the resin path and the holding pressure path, comprising the steps of:
(a) maintaining the first pressure of the resin in the resin path and the holding pressure path by pressurization of a holding pressure device from the resin path side during a predetermined time;
(b) then shutting off the resin path and maintaining a second pressure of the resin in the holding pressure path by pressurization from the holding pressure path side;
(c) after the step (b) of maintaining the second pressure of the resin in the resin path and the holding pressure path by pressurization of the holding pressure device from the holding pressure path side, shutting off an inlet path for the resin on a mold side and releasing pressurization from the holding pressure path side once; and
(d) opening the resin path and discharging all the resin held in the holding pressure path to the resin path under pressure by further pressurizing in the holding pressure path to thereby discharge all the resin in the holding pressure path to the resin path.

2. The resin injection method according to claim 1 , wherein during the step (d) the tip site of the holding pressure device is projected into the resin path from the holding pressure path for discharging all the resin in the holding pressure path to the resin path.

3. The resin injection method according to claim 1 , wherein the first pressure and the second pressure are equal to each other.

4. The resin injection method according to claim 1 , wherein pressurizing the resin in the resin path is performed by an injection cylinder during the step (a) of maintaining the first pressure of the resin in the resin path and the holding pressure path by pressurization from the resin path side.

5. A resin injection method for injecting a resin from an injection nozzle through a resin path, by advancing a resin injection device, and flowing the resin into a holding pressure path communicating with the resin path to maintain a first pressure of the resin in the resin path and the holding pressure path, the method comprising the steps of:
(a) putting a holding pressure device, for selectively advancing in the holding pressure path to apply pressure in the holding pressure path, or a pressure holding position to maintain pressure in the holding pressure path, or to retract to reduce pressure in the pressure holding path, into a free state where the holding pressure device is responsive to pressure in the resin path to retract;
(b) while the pressure holding device is in a free state, advancing the resin injection device to apply pressure in the resin path during an initial time (t 0 ) to a first time (t 1 ), during which time a shutoff plunger for shutting off resin flow in the resin path upstream of the holding pressure device is kept in an open position and a shutoff member for shutting off resin flow in the resin path downstream of the holding pressure device on a mold side thereof is kept in an open position, to charge the holding pressure path with resin and to fill the mold with resin;
(c) at the first time (t 1 ) continuing to advance the resin injection device until a second time (t 2 ) while the pressure holding device maintains position;
(d) at the second time (t 2 ) closing the shutoff plunger while the shutoff member remains open and the injection device maintains position and while the holding pressure device maintains position;
(e) at a third time (t 3 ) keeping the shutoff plunger closed and keeping the shutoff member open and again advancing the holding pressure device;
(f) after the third time (t 3 ) and before a fourth time (t 4 ), stopping the advance of the holding pressure device and subsequently thereto retracting the injection device until the fourth time (t 4 ) for charging the injection device;
(g) at the fourth time (t 4 ) closing the shutoff member and maintaining the shutoff plunger closed, and continuing to retract the injection device while again retracting the holding pressure device; and
(h) at a fifth time (t 5 ) ceasing retraction of the holding pressure device and again advancing the holding device, opening the shutoff plunger while maintaining the shutoff member closed, and continuing to retract the injection device.

6. The resin injection method according to claim 5 , wherein in the step (h), the pressure holding device is advanced until a tip of the pressure holding device extends into the resin path.

7. The resin injection method according to claim 6 , wherein in the step (f), the pressure holding device is advanced less than in the step (h).

Assignees

• Nissei Asb Machine Co Ltd

Inventors

• Horigome Hiroshi
• Hidaka Yasuhiro

Classifications

• B29L2031/7158

  Bottles · CPC title

• B29C45/50

  Axially movable screw · CPC title

• B29K2105/253

  Preform · CPC title

• B29K2067/003

  PET, i.e. poylethylene terephthalate · CPC title

• B29C45/54

  and plasticising screw {(B29C45/532 takes precedence)} · CPC title