US5071603A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of controlling hydraulic press
Assignee: Kobe Steel Ltd
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Filing: 1988-12-13
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Granted: 1991-12-10
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Expires: 2008-12-13
Abstract
Abstract A method of controlling a hydraulic press wherein changing over from velocity control to pressure control can be effected at an optimum point of time in accordance with a condition of material being filled. When a movable mold half of a metal mold is moved by a hydraulic cylinder to compression mold a work within a cavity defined in the metal mold, the velocity of movement of the mold half by the hydraulic cylinder is controlled until pressurization of the work is started, but after starting of the pressurization, the pressurizing force of the hydraulic cylinder is controlled. During the velocity control, a parameter which varies as the compression proceeds is successively detected during the velocity control, and changing over from the velocity control to the pressure control is effected at a point of time when the detected parameter coincides with a preset value--that is, when the work is fully filled in the cavity. A device for controlling a hydraulic press is also disclosed wherein optimal pressure control can be assured in accordance with a current condition of material for molding.
Inventors
- 👤 Masanobu Kurumaji
- 👤 Naoki Takeuchi
- 👤 Tutomu Sano
- 👤 Kazuyuki Kajiyama
- 👤 Noriharu Nakagawa
- 👤 Hiroaki Kondo
- 👤 Etujiro Imanishi
- 👤 Hiroshi Ueda
- 👤 Yoshihiro Fukuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:59
CPC Classifications
B; B30; B30B; B30B15/00; B30B15/26; B29; B29C; B29C43/00; B29C43/32; B29C43/58; B30B15/16; B30B15/18; B30B15/20; B30B15/22; B29C2043/5808
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
139 words
In a method of controlling a hydraulic press wherein, when at least one of a pair of metal mold halves is moved by a hydraulic cylinder to compression mold a work within a cavity defined between said metal mold halves, the velocity of movement of said at least one metal mold half by said hydraulic cylinder toward the work is controlled until pressurization of the work is started, but after starting of the pressurization, the pressurizing force of said hydraulic cylinder is controlled, the improvement wherein: (a) a position of a movable member which is moved by said hydraulic cylinder is successively detected during the velocity control, and (b) changing over from the velocity control to the pressure control is effected at a point of time when the detected position of said movable member coincides with a preset value.
Claim 2
Dependent Claim
139 words
In a method of controlling a hydraulic press wherein, when at least one of a pair of metal mold halves is moved by a hydraulic cylinder to compression mold a work within a cavity defined between said metal mold halves, the velocity of movement of said at least one metal mold half by said hydraulic cylinder toward the work is controlled until pressurization of the work is started, but after starting of the pressurization, the pressurizing force of said hydraulic cylinder is controlled, the improvement wherein: (a) a position of a movable member which is moved by said hydraulic cylinder is successively detected during the velocity control, and (b) changing over from the velocity control to the pressure control is effected at a point of time when the detected position of said movable member coincides with a preset value.
Claim 3
Dependent Claim
219 words
In a method of controlling a hydraulic press wherein, when at least one of a pair of metal mold halves is moved by a hydraulic cylinder to compression mold a work within a cavity defined between said metal mold halves, the velocity of movement of the metal mold half by said hydraulic cylinder is controlled until pressurization of the work is started, but after starting of the pressurization, the pressurizing force of said hydraulic cylinder is controlled, the improvement wherein changing over from the velocity control to the pressure control is effected at a point of time when said hydraulic cylinder is moved to a position of a predetermined stroke value Z 0 and an internal pressure P of said cavity is detected upon such changing over and is compared with a predetermined preset internal pressure P 0 to obtain a stroke modifying amount VZ for modifying the internal pressure P of said cavity to the predetermined internal pressure P 0 in accordance with an equation VZ=α(P.sub.0 -P) where α is a coefficient, and then a stroke value of said hydraulic cylinder at which changing over from velocity control to pressure control is to be effected in a subsequent next molding cycle is modified to Z 0 +V Z, and wherein such modification is repeated for each molding cycle.
Claim 4
Dependent Claim
219 words
In a method of controlling a hydraulic press wherein, when at least one of a pair of metal mold halves is moved by a hydraulic cylinder to compression mold a work within a cavity defined between said metal mold halves, the velocity of movement of the metal mold half by said hydraulic cylinder is controlled until pressurization of the work is started, but after starting of the pressurization, the pressurizing force of said hydraulic cylinder is controlled, the improvement wherein changing over from the velocity control to the pressure control is effected at a point of time when said hydraulic cylinder is moved to a position of a predetermined stroke value Z 0 and an internal pressure P of said cavity is detected upon such changing over and is compared with a predetermined preset internal pressure P 0 to obtain a stroke modifying amount VZ for modifying the internal pressure P of said cavity to the predetermined internal pressure P 0 in accordance with an equation VZ=α(P.sub.0 -P) where α is a coefficient, and then a stroke value of said hydraulic cylinder at which changing over from velocity control to pressure control is to be effected in a subsequent next molding cycle is modified to Z 0 +V Z, and wherein such modification is repeated for each molding cycle.
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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) | 1994-12-09 | 1995-06-10 | 1995-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-09 | 1999-06-10 | 1999-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-09 | 2003-06-10 | 2003-12-10 | $7700.00 | Window Closed / Lapsed |