US4749536A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Injection molding method for filling mold and maintaining pressure
Assignee: Tri-Delta Technology Inc
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Filing: 1987-07-21
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Granted: 1988-06-07
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Expires: 2007-07-21
Abstract
Abstract The present invention increases the shot capacity and the screw recovery time of an injection molding machine without increasing hydraulic pump capacity or motor horsepower. In accordance with one aspect of the invention, an existing injection molding machine is retrofitted with two cylinder and piston arrangements which are bolted onto the machine between its plasticizer barrel and its melt manifold. One of the cylinder and piston arrangements is employed to perform a mold-filling operation, whereas the other cylinder and piston arrangement is employed to perform packing and suck back operations.
Inventors
- 👤 John J. Farrell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:28
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C45/53; B29C45/54; B29C45/57
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
287 words
A method of increasing the shot capacity and the screw recovery time of an existing injection molding machine, which includes an extruder, having an interior chamber and a screw mounted for rotation within said interior chamber of said extruder such that said screw, upon its rotation, conveys plastic material through said interior chamber of said extruder, and a mold communicating with said extruder through a flow path extending between said mold and said interior chamber of said extruder, said method comprising the step of retrofitting said injection molding machine with controlling means arranged in said flow path between said extruder and said mold for controlling the flow of plastic material through said flow path, said controlling means being movable between a closed position in which said controlling means prevents plastic material from flowing through said flow path and an open position in which said controlling means permits plastic material to flow through said flow path, receiving means in communication with said flow path at a point between said extruder and said controlling means for receiving plastic material which is conveyed through said flow path from said extruder when said controlling means is in its closed position, injecting means for injecting the plastic material received in said receiving means into said mold when said controlling means is in its open position, and maintaining means in communication with said flow path at a point between said mold and said controlling means for maintaining pressure on the plastic material which is contained in said mold when said controlling means is in its closed position, whereby said extruder can supply plastic material to said receiving means while said maintaining means continues to maintain the plastic material in the mold under pressure.
Claim 2
Independent Claim
287 words
A method of increasing the shot capacity and the screw recovery time of an existing injection molding machine, which includes an extruder, having an interior chamber and a screw mounted for rotation within said interior chamber of said extruder such that said screw, upon its rotation, conveys plastic material through said interior chamber of said extruder, and a mold communicating with said extruder through a flow path extending between said mold and said interior chamber of said extruder, said method comprising the step of retrofitting said injection molding machine with controlling means arranged in said flow path between said extruder and said mold for controlling the flow of plastic material through said flow path, said controlling means being movable between a closed position in which said controlling means prevents plastic material from flowing through said flow path and an open position in which said controlling means permits plastic material to flow through said flow path, receiving means in communication with said flow path at a point between said extruder and said controlling means for receiving plastic material which is conveyed through said flow path from said extruder when said controlling means is in its closed position, injecting means for injecting the plastic material received in said receiving means into said mold when said controlling means is in its open position, and maintaining means in communication with said flow path at a point between said mold and said controlling means for maintaining pressure on the plastic material which is contained in said mold when said controlling means is in its closed position, whereby said extruder can supply plastic material to said receiving means while said maintaining means continues to maintain the plastic material in the mold under pressure.
Claim 3
Dependent Claim
24 words
A method according to claim 1, wherein said screw of said extruder is mounted for reciprocating movement within said interior chamber of said extruder.
Claim 4
Dependent Claim
25 words
A method according to claim 1, wherein said screw of said extruder is not mounted for reciprocating movement within said interior chamber of said extruder.
Claim 5
Dependent Claim
59 words
A method according to claim 1, wherein said receiving means includes an interior chamber of a cylinder, said interior chamber of said cylinder communicating with said flow path at said point between said extruder and said controlling means, and wherein said injecting means includes a plunger which is mounted for reciprocating movement within said interior chamber of said cylinder.
Claim 6
Dependent Claim
22 words
A method according to claim 4, wherein said plunger is movable in said cylinder between an extended position and a retracted position.
Claim 7
Dependent Claim
33 words
A method according to claim 5, wherein said plunger is movable from its extended position to its retracted position by plastic material supplied to said interior chamber of said cylinder by said extruder.
Claim 8
Dependent Claim
32 words
A method according to claim 6, wherein said screw of said extruder is mounted for reciprocating movement in said interior chamber of said extruder between an extended position and a retracted position.
Claim 9
Dependent Claim
39 words
A method according to claim 7, wherein said screw is movable from its extended position to its retracted position by back pressure exerted on the plastic material in said interior chamber of said cylinder and transmitted to said screw.
Claim 10
Dependent Claim
32 words
A method according to claim 8, wherein said extruder includes inhibiting means for inhibiting the plastic material conveyed through said interior chamber of said extruder by said screw from reentering said screw.
Claim 11
Dependent Claim
24 words
A method according to claim 9, wherein said inhibiting means includes a check ring disposed about said screw adjacent to a discharge end thereof.
Claim 12
Dependent Claim
49 words
A method according to claim 7, wherein said screw and said plunger are simultaneously movable from their respective retracted positions to their respective extended positions when said controlling means is in its open position, whereby said screw and said plunger cooperate to inject the plastic material into said mold.
Claim 13
Dependent Claim
56 words
A method according to claim 4, wherein said maintaining means includes an interior chamber of another cylinder, said interior chamber of said another cylinder communicating with said flow path at said point between said mold and said controlling means, and another plunger which is mounted for reciprocating movement within said interior chamber of said another cylinder.
Claim 14
Dependent Claim
23 words
A method according to claim 1, wherein said receiving means, said injecting means and said maintaining means are removably attached to said extruder.
Claim 15
Dependent Claim
142 words
An injection molding method in which plastic material is supplied to a mold from an extruder through a flow part which extends between said mold and said extruder, said method comprising the steps of closing said flow path at a first point between said mold and said extruder, extruding plastic material from said extruder to receiving means which communicates with said flow path at a second point between said first point and said extruder, opening said flow path at said first point, injecting the plastic material from said receiving means into said mold through said flow path, closing said flow path at said first point, and maintaining the plastic material in said mold under pressure by exerting pressure on the plastic material at a third point along said flow path, said third point being located between said first point and said mold.
Claim 16
Dependent Claim
142 words
An injection molding method in which plastic material is supplied to a mold from an extruder through a flow part which extends between said mold and said extruder, said method comprising the steps of closing said flow path at a first point between said mold and said extruder, extruding plastic material from said extruder to receiving means which communicates with said flow path at a second point between said first point and said extruder, opening said flow path at said first point, injecting the plastic material from said receiving means into said mold through said flow path, closing said flow path at said first point, and maintaining the plastic material in said mold under pressure by exerting pressure on the plastic material at a third point along said flow path, said third point being located between said first point and said mold.
Claim 17
Dependent Claim
36 words
An injection molding method according to claim 14, wherein said extruder includes a rotatable screw which is mounted for reciprocating movement within an interior chamber of said extruder between an extended position and a retracted position.
Claim 18
Dependent Claim
52 words
An injection molding method according to claim 15, further comprising the step of moving said screw from its retracted position to its extended position simultaneously with the injection of plastic material into said mold from said receiving means, whereby said screw cooperates in the injection of the plastic material into the mold.
Claim 19
Dependent Claim
38 words
An injection molding method according to claim 16, wherein said screw is moved from its extended position to its retracted position by back pressure exerted on the plastic material in said receiving means and transmitted to said screw.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-07 | 1991-12-07 | 1992-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-07 | 1995-12-07 | 1996-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-07 | 1999-12-07 | 2000-06-07 | $7700.00 | Window Closed / Lapsed |