Patent US3771802A successfully refreshed from Google Patents.
US3771802A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for controlling chucking pressures on workpieces in machine tools
Assignee: NTN Corp
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Filing: 1971-05-05
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Granted: 1973-11-13
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Expires: 1991-05-05
Abstract
Abstract The present invention provides a method of and apparatus for controlling chucking pressures on workpieces in machine tools carrying out machining operations by chucking the widths, outer surfaces or inner surfaces of workpieces with hydraulic pressure, magnetic forces or mechanical force, the principal arrangement thereof being such that in order that the internal stresses in a workpiece may be dissipated or relieved in accordance with changes in the cutting speed in an automatic working cycle thereby to improve the accuracy of finishing, the chucking pressures are properly adjusted. It also provides methods of and apparatuses for controlling chucking pressures on workpieces in machine tools, having sub-arrangements based on said principal arrangement. Advantages and details of such arrangements will be made clear.
Inventors
- 👤 S Hiramatu
- 👤 T Egusa
- 👤 H Tateisi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:52
CPC Classifications
B; B23; B23Q; B23Q3/00; B23Q3/16; B24; B24B; B24B41/00; B24B41/06; Y; Y10; Y10T; Y10T279/00; Y10T279/12; Y10T279/1208; Y10T82/00; Y10T82/10; Y10T82/25; Y10T82/2552; Y10T82/2562
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
287 words
An apparatus for controlling chucking pressures on workpieces comprising, in combination: a. a pressure operated chuck cylinder, b. a fluid pressure line connected thereto, c. a source of fluid pressure, d. a chuck pressure change-over valve connected between said source and said line and operable to admit fluid pressure from said source to said line, e. a pressure indicator connected to said line, f. a first pressure-reducing throttling valve connected to said line for providing throttled discharge of fluid pressure from said line for establishing a first chucking pressure in said line when said change-over valve is opened to admit fluid pressure from said source to said line, g. means comprising a second pressure-reducing throttling valve connected to said source and to said line in parallel with said change-over valve for supplying fluid at reduced pressure to said line for establishing in said line with said first throttling valve a second chucking pressure less than said first chucking pressure when said change-over valve is closed, h. a pressure accumulator connected to said line for regulating the rate of pressure change therein when said change-over valve is closed, for inhibiting misalignment of the work thereby, i. a third connection from said source to said line, said third connection comprising in series therein a cut-off valve and a third throttling valve, and j. said first, second and third throttling valves and accumulator constituting means operable for causing the pressure in said line to drop to a pressure lower than said reduced pressure when said change-over valve and cut-off valve are closed for relieving strains in the work, and operable for causing the pressure in said line to thereafter rise to said reduced pressure when said cut-off valve is opened.
Claim 2
Independent Claim
287 words
An apparatus for controlling chucking pressures on workpieces comprising, in combination: a. a pressure operated chuck cylinder, b. a fluid pressure line connected thereto, c. a source of fluid pressure, d. a chuck pressure change-over valve connected between said source and said line and operable to admit fluid pressure from said source to said line, e. a pressure indicator connected to said line, f. a first pressure-reducing throttling valve connected to said line for providing throttled discharge of fluid pressure from said line for establishing a first chucking pressure in said line when said change-over valve is opened to admit fluid pressure from said source to said line, g. means comprising a second pressure-reducing throttling valve connected to said source and to said line in parallel with said change-over valve for supplying fluid at reduced pressure to said line for establishing in said line with said first throttling valve a second chucking pressure less than said first chucking pressure when said change-over valve is closed, h. a pressure accumulator connected to said line for regulating the rate of pressure change therein when said change-over valve is closed, for inhibiting misalignment of the work thereby, i. a third connection from said source to said line, said third connection comprising in series therein a cut-off valve and a third throttling valve, and j. said first, second and third throttling valves and accumulator constituting means operable for causing the pressure in said line to drop to a pressure lower than said reduced pressure when said change-over valve and cut-off valve are closed for relieving strains in the work, and operable for causing the pressure in said line to thereafter rise to said reduced pressure when said cut-off valve is opened.
References Cited (Backward Citations)
US2731952A
Cited
US3091256A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |