Patent US4229635A successfully refreshed from Google Patents.
US4229635A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control of an electro-discharge machine tool
Assignee: Rolls Royce PLC
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Filing: 1978-09-12
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Granted: 1980-10-21
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Expires: 1998-09-12
Abstract
Abstract Electro-discharge machining device including means for preventing the machining electrode from surging forward when the electrode breaks through a workpiece. The machining electrode is mounted on a first movable member including a portion which engages a motor driven second movable member. Once the first and second movable members are engaged, the first movable member is constrained to move toward the workpiece at a speed no greater than the speed of the second movable member. Sensing and signalling means control the speed of the second movable member by a signal representing the proximity of the first and second movable members.
Inventors
- 👤 Raymond Dinsdale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 19:34
CPC Classifications
B; B23; B23H; B23H7/00; B23H7/14; B23H7/18
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
203 words
Electro-discharge machining apparatus for machining a workpiece comprising: a first movable member for carrying an electrode; servo control means for controlling the speed of said first movable member in response to the voltage between said electrode and a surface of said workpiece; a second movable member against which said first member is located in relative sliding engagement; said first and second movable members having overlapping portions for limiting the motion of said first movable member in a direction toward said workpiece and with respect to said second movable member by causing abutting engagement; sensing and signalling means coupled to said second movable member for sensing the relative position of said first movable member with respect to said second movable member and generating a position signal related thereto; and drive means responsive to said position signal for moving said second movable member toward said workpiece at a speed relative to the speed of said first movable member so as to control the abutting of said overlapping portions, whereby after the abutting of said overlapping portions, the speed of said first movable member toward said workpiece and the speed of said electrode are controlled by the speed of said second movable member toward said workpiece.
Claim 2
Dependent Claim
203 words
Electro-discharge machining apparatus for machining a workpiece comprising: a first movable member for carrying an electrode; servo control means for controlling the speed of said first movable member in response to the voltage between said electrode and a surface of said workpiece; a second movable member against which said first member is located in relative sliding engagement; said first and second movable members having overlapping portions for limiting the motion of said first movable member in a direction toward said workpiece and with respect to said second movable member by causing abutting engagement; sensing and signalling means coupled to said second movable member for sensing the relative position of said first movable member with respect to said second movable member and generating a position signal related thereto; and drive means responsive to said position signal for moving said second movable member toward said workpiece at a speed relative to the speed of said first movable member so as to control the abutting of said overlapping portions, whereby after the abutting of said overlapping portions, the speed of said first movable member toward said workpiece and the speed of said electrode are controlled by the speed of said second movable member toward said workpiece.
Claim 3
Dependent Claim
25 words
Electro-discharge machining apparatus according to claim 1 wherein said drive means comprises a stepping motor coupled via a lead screw, to said second movable member.
Claim 4
Dependent Claim
32 words
Electro-discharge machining apparatus according to claim 2 wherein said sensing and signalling means comprises a coil controlled oscillator for generating signals related to the proximity of said first and second movable members.
Claim 5
Dependent Claim
55 words
Electro-discharge machining apparatus according to claim 3 further including a timer mechanism coupled to said stepping motor for controlling the time taken for said stepping motor to reach a speed of operation which will ensure abutting of said overlapping portions, after said motor has received a first position signal from said sensing and signalling means.
Claim 6
Dependent Claim
76 words
Electro-discharge apparatus according to claim 4 wherein said timer mechanism includes means for effecting a series of motor speed changes from a first speed which drives said second movable member faster than said first movable member, to a final speed which drives said second movable member more slowly than said first movable member, so as to ensure the obtaining of abutting of said overlapping portions, said speed changes being caused to occur at equal time intervals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-21 | 1984-04-21 | 1984-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-21 | 1988-04-21 | 1988-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-21 | 1992-04-21 | 1992-10-21 | $7700.00 | Window Closed / Lapsed |