US3590439A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shutoff device for an injection molding machine
Assignee: Individual
•
Filing: 1969-04-28
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Granted: 1971-07-06
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Expires: 1989-04-28
Abstract
Abstract A shutoff device for use with a rotating feed screw of an injection molding machine including a head portion in which a chamber is formed for directing a plastic material to a mold or die, a pin being located within the chamber, and the pin and head portion having relative movement so that upon rotation of the feed screw during the feeding operation, the feed screw has open communication with the mold or die, but during the injecting operation, the feed screw is sealed against backflow of material from the mold or die.
Inventors
- 👤 Eskil P Swanson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:55
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C45/47; B29C45/50; B29C45/52; Y; Y10; Y10S; Y10S425/00; Y10S425/224; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7837; Y10T137/7904; Y10T137/7908; Y10T137/7909; Y10T137/7913
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
208 words
In a shutoff device for use with a feed screw of an injection molding machine, a head portion having a chamber formed therein into which a plastic material is introduced by said feed screw, an opening formed in said head portion and normally communicating with said chamber during feeding of the material by said screw, and an elongated pin located in said chamber, said head portion and pin having relative axial movement in a first direction under pressure of said plastic material during the feeding operation to provide for flow of said plastic material into said chamber and outwardly of said head portion, and having relative movement in a direction opposite to said first direction under pressure of backflow of said plastic material to seal said opening and thereby prevent said plastic material from flowing back toward said screw during the injection period of the injection molding process, said head portion having opposed undercut grooves formed interiorly thereof that communicate with said chamber, and opposed lugs formed on said pin and being receivable in said undercut grooves, said undercut grooves being substantially greater in axial dimension than said lugs, wherein said undercut grooves define limits for said lugs during the relative movement of said head portion and pin.
Claim 2
Dependent Claim
208 words
In a shutoff device for use with a feed screw of an injection molding machine, a head portion having a chamber formed therein into which a plastic material is introduced by said feed screw, an opening formed in said head portion and normally communicating with said chamber during feeding of the material by said screw, and an elongated pin located in said chamber, said head portion and pin having relative axial movement in a first direction under pressure of said plastic material during the feeding operation to provide for flow of said plastic material into said chamber and outwardly of said head portion, and having relative movement in a direction opposite to said first direction under pressure of backflow of said plastic material to seal said opening and thereby prevent said plastic material from flowing back toward said screw during the injection period of the injection molding process, said head portion having opposed undercut grooves formed interiorly thereof that communicate with said chamber, and opposed lugs formed on said pin and being receivable in said undercut grooves, said undercut grooves being substantially greater in axial dimension than said lugs, wherein said undercut grooves define limits for said lugs during the relative movement of said head portion and pin.
Claim 3
Dependent Claim
56 words
In a shutoff device as set forth in claim 1, the cross section of the major portion of said pin being noncircular, wherein a plurality of flat surfaces are formed on the body of the pin, said flat surfaces cooperating with adjacent walls of said passage to define flow passages for said material during feeding thereof.
Claim 4
Dependent Claim
85 words
In a shutoff device as set forth in claim 2, opposed holes formed in said head portion that communicate with the undercut grooves, said opposed holes receiving said lugs therein and providing for locating said lugs in said undercut grooves when said head portion and pin are assembled together, relative rotary movement between said head portion and pin further locking said lugs in said undercut grooves so that the relative axial movement between said pin and head portion can be accomplished without the disassembly thereof.
Claim 5
Dependent Claim
68 words
In a shutoff device as set forth in claim 1, said head portion being fixed to said feed screw, said chamber having a conical seat adjacent to said opening defining a sealing surface, said pin being movable relative to said head portion and having a corresponding tapered surface that is engageable with said conical seat during the injection period to prevent backflow of said material into said screw.
Claim 6
Dependent Claim
70 words
In a shutoff device as set forth in claim 4, said elongated movable pin having a rear portion on which the tapered surface is formed, and having a tapered forward portion that extends outwardly of said head portion, the lateral dimension of said pin being less than the diameter of said chamber, wherein a flow passage for said material is defined between the walls of said chamber and said pin.
Claim 7
Dependent Claim
42 words
In a shutoff device as set forth in claim 4, said pin having a bore formed therein that communicates with said chamber and receives said material therefrom, wherein the material is discharged from the bore in said pin during the feeding operation.
Claim 8
Dependent Claim
60 words
In a shutoff device as set forth in claim 1, said elongated pin being joined to said feed screw and having opposed lugs forMed thereon, said head portion being mounted on said pin for axial movement relative thereto and having a central bore communicating with the chamber therein outwardly from which the plastic material is directed during the feeding operation.
Claim 9
Dependent Claim
67 words
In a shutoff device as set forth in claim 7, a conical surface being located in said head portion adjacent to the opening therein, and a corresponding tapered surface formed on said pin, and cooperating with the conical surface in the head portion to form a seal therewith when said head portion is moved in a reverse direction relative to said pin during the injection molding period.
Claim 10
Dependent Claim
97 words
In a shutoff device as set forth in claim 1, said pin having a nose portion formed thereon to which a body is joined, the base of said nose portion having a diameter that is greater than the cross-sectional dimension of said body, wherein a tapered surface is defined therebetween, said chamber having a conical seat adjacent to said opening defining a sealing surface, said pin being movable relative to said head portion in response to backflow of said material, whereby said tapered surface engages the conical seat to prevent backflow of the material in said screw.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-05 | 1975-01-04 | 1975-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-05 | 1979-01-04 | 1979-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-05 | 1983-01-04 | 1983-07-06 | $7700.00 | Window Closed / Lapsed |