US3932083A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Injection molding control
Assignee: Bankers Trust Co
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Filing: 1974-11-29
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Granted: 1976-01-13
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Expires: 1994-11-29
Abstract
Abstract The control system for an injection molding machine providing successive fill, compaction, hold, cure and mold open times. The ram position and mold pressure are monitored at predetermined times respectively after the molding cycle has begun. If the ram position is out of tolerance, the fill pressure is adjusted to compensate for the deviation. If the mold pressure is out of tolerance, the compaction pressure is adjusted to compensate for the deviation in mold pressure.
Inventors
- 👤 Jon E. Boettner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:44
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/76
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
238 words
An automatic control system for injection molding machines having a reciprocable ram for injecting plasticized materials from an extrusion barrel into a mold cavity, said system comprising a position transducer producing a position signal varying with the position of the ram, a position setpoint means establishing a position setpoint signal, a position sample timer producing a position sample signal at a predetermined time after initiation of an injection cycle, a position comparator supplying a position deviation signal in response to deviation of said position signal from the position setpont signal upon occurrence of said position sample signal, means for adjusting a fill pressure in compliance with the position deviation signal to compensate for said position deviation, a pressure transducer producing a pressure signal varying with the pressure in said mold cavity, a pressure setpoint means establishing a pressure setpoint signal, a pressure sample timer producing a pressure sample signal at a predetermined second time after initiation of the injection cycle, a pressure comparator supplying a pressure deviation signal in response to deviation of said pressure signal from the pressure setpoint signal upon occurrence of said pressure sample signal, and means for adjusting a compaction pressure in compliance with the pressure deviation signal to compensate for said pressure deviation, said position sample signal being produced prior to completion of filling of the mold cavity, and said pressure sample signal being produced after completion of filling of the mold cavity.
Claim 2
Dependent Claim
238 words
An automatic control system for injection molding machines having a reciprocable ram for injecting plasticized materials from an extrusion barrel into a mold cavity, said system comprising a position transducer producing a position signal varying with the position of the ram, a position setpoint means establishing a position setpoint signal, a position sample timer producing a position sample signal at a predetermined time after initiation of an injection cycle, a position comparator supplying a position deviation signal in response to deviation of said position signal from the position setpont signal upon occurrence of said position sample signal, means for adjusting a fill pressure in compliance with the position deviation signal to compensate for said position deviation, a pressure transducer producing a pressure signal varying with the pressure in said mold cavity, a pressure setpoint means establishing a pressure setpoint signal, a pressure sample timer producing a pressure sample signal at a predetermined second time after initiation of the injection cycle, a pressure comparator supplying a pressure deviation signal in response to deviation of said pressure signal from the pressure setpoint signal upon occurrence of said pressure sample signal, and means for adjusting a compaction pressure in compliance with the pressure deviation signal to compensate for said pressure deviation, said position sample signal being produced prior to completion of filling of the mold cavity, and said pressure sample signal being produced after completion of filling of the mold cavity.
Claim 3
Dependent Claim
25 words
An automatic control system according to claim 1 wherein said sample timers produce the sample signals at adjustable times after initiation of said injection cycle.
Claim 4
Dependent Claim
14 words
An automatic control system according to claim 1 wherein said setpoint means are adjustable.
Claim 5
Dependent Claim
17 words
An automatic control system according to claim 1 wherein said setpoint means determine upper and lower limits.
Claim 6
Dependent Claim
19 words
An automatic control system according to claim 1 wherein the deviation signals supplied by said comparators are step signals.
References Cited (Backward Citations)
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Cited
US3721512A
Cited
US3693946A
Cited
US3767339A
Cited
US3752363A
Cited
US3840312A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-12 | 1979-07-14 | 1980-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-12 | 1983-07-14 | 1984-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-12 | 1987-07-14 | 1988-01-13 | $7700.00 | Window Closed / Lapsed |