Patent US4847797A successfully refreshed from Google Patents.
US4075792A
Expired / Lapsed
US
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System for controlling the advance of a rotary machine tool
Assignee: Buderus AG
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Filing: 1976-04-15
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Granted: 1978-02-28
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Expires: 1996-04-15
Abstract
Abstract A rotary machine tool, such as a grinding wheel, is mounted on a movable support serving to advance the tool toward a workpiece, such as a pipe to be severed thereby. The tool is driven by an electric motor whose operating current is measured by a sensor controlling the fluid supply to a hydraulic servomotor which is linked with the support. When the advance is too rapid, the resulting rise in load resistance increases the operating current and causes a throttling of the fluid pressure, the rate of advance being thus optimized in conformity with the shape and/or composition of the workpiece.
Inventors
- 👤 Jurgen Schreiber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:41
CPC Classifications
B; B24; B24B; B24B49/00; B24B49/16; B23; B23D; B23D47/00; B23D47/08; B23D47/10; B24B27/00; B24B27/06; B24B27/0683; B24B27/0691
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
279 words
A system for machining a workpiece, comprising: a workpiece holder; a rotary machine tool engageable with a workpiece on said holder; p1 a support for said tool movable relatively to said holder for advancing said tool toward said workpiece; an electric motor coupled with said tool for rotating same about an axis; current-sensing means in circuit with said motor; a reversible hydraulic servomotor linked with said support and provided with a high-rate fluid-supply circuit including a first valve and with a low-rate fluid-supply circuit including a second valve, each of said valves having a forward-flow position, a neutral position and a reverse-flow position; control means responsive to said current-sensing means for placing said first valve in its forward-flow position to advance said tool rapidly toward the workpiece under low-current conditions during an approach phase and for actuating said second valve while maintaining said first valve in its neutral position to displace said tool more slowly under high-current conditions, indicative of an engagement of the tool with the workpiece, at speeds tending to maintain the motor current in a predetermined range during a working phase following said approach phase, with reversal of the flow in said low-rate fluid-supply circuit upon detection of an overload condition by said current-sensing means; and switchover means responsive to a predetermined advance of said tool from a starting position for modifying the operation of said control circuit to hold said second valve in its neutral position while shifting said first valve into its reverse-flow position upon a recurrence of said low-current conditions due to severance of the workpiece for rapidly retracting said tool to said starting position in a withdrawal phase following said working phase.
Claim 2
Independent Claim
279 words
A system for machining a workpiece, comprising: a workpiece holder; a rotary machine tool engageable with a workpiece on said holder; p1 a support for said tool movable relatively to said holder for advancing said tool toward said workpiece; an electric motor coupled with said tool for rotating same about an axis; current-sensing means in circuit with said motor; a reversible hydraulic servomotor linked with said support and provided with a high-rate fluid-supply circuit including a first valve and with a low-rate fluid-supply circuit including a second valve, each of said valves having a forward-flow position, a neutral position and a reverse-flow position; control means responsive to said current-sensing means for placing said first valve in its forward-flow position to advance said tool rapidly toward the workpiece under low-current conditions during an approach phase and for actuating said second valve while maintaining said first valve in its neutral position to displace said tool more slowly under high-current conditions, indicative of an engagement of the tool with the workpiece, at speeds tending to maintain the motor current in a predetermined range during a working phase following said approach phase, with reversal of the flow in said low-rate fluid-supply circuit upon detection of an overload condition by said current-sensing means; and switchover means responsive to a predetermined advance of said tool from a starting position for modifying the operation of said control circuit to hold said second valve in its neutral position while shifting said first valve into its reverse-flow position upon a recurrence of said low-current conditions due to severance of the workpiece for rapidly retracting said tool to said starting position in a withdrawal phase following said working phase.
Claim 3
Dependent Claim
37 words
A system as defined in claim 1, wherein said tool is a grinding wheel, said holder comprising a pair of idler roller for supporting said workpiece with freedom of rotation about an axis parallel to said axis.
References Cited (Backward Citations)
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Cited
US2961808A
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US3524285A
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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) | 1981-02-27 | 1981-08-29 | 1982-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-27 | 1985-08-29 | 1986-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-27 | 1989-08-29 | 1990-02-28 | $7700.00 | Window Closed / Lapsed |