US3814893A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrode-feeding device for an electrical discharge machining apparatus
Assignee: Westinghouse Electric Corp
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Filing: 1973-03-05
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Granted: 1974-06-04
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Expires: 1993-03-05
Abstract
Abstract A reversible servo-motor having a rotatable shaft is mounted on a base plate and an arm is fixed to the shaft to guide an electrical discharge machining electrode along a circular path to form the convex and concave surfaces of two adjacent air foils that make up the nozzles of a nozzle block of a steam turbine.
Inventors
- 👤 J Helms
- 👤 R Fischer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:45
CPC Classifications
B; B23; B23H; B23H9/00; B23H9/10; F; F01; F01D; F01D9/00; F01D9/02; F01D9/04; F01D9/047
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
225 words
An electrical discharge machining apparatus having an electrode feeding head capable of moving an electrode rectilinearly in a plurality of directions for machining the nozzle blades in a nozzle block of a steam turbine, the improvement in said apparatus comprising a base plate fastened to said electrode feeding head; a reversible servo-motor having a rotatable shaft; an electrode guide arm which comprises a first portion fastened to said rotatable shaft, a second portion disposed generally normal to said first portion and a third portion fastened to said second portion, said third portion having means for holding an electrode disposed therein; said base plate having an arcuate shaped elongated hole disposed therein, said first portion of the guide arm having rolling means connected thereto, said rolling means being disposed to engage said base plate; a carriage disposed on the opposite side of said base plate from said guide arms; means extending through said elongated opening to join said carriage to said first portion of said guide arm in order to minimize the bending of said first portion of said guide arm; and a curved electrode, said electrode being shaped to electrically discharge machine the concave portion of one nozzle blade and the adjacent convex portion of another nozzle blade as said electrode is fed into said nozzle block by said electrode guiding arm and said servo-motor.
Claim 2
Dependent Claim
225 words
An electrical discharge machining apparatus having an electrode feeding head capable of moving an electrode rectilinearly in a plurality of directions for machining the nozzle blades in a nozzle block of a steam turbine, the improvement in said apparatus comprising a base plate fastened to said electrode feeding head; a reversible servo-motor having a rotatable shaft; an electrode guide arm which comprises a first portion fastened to said rotatable shaft, a second portion disposed generally normal to said first portion and a third portion fastened to said second portion, said third portion having means for holding an electrode disposed therein; said base plate having an arcuate shaped elongated hole disposed therein, said first portion of the guide arm having rolling means connected thereto, said rolling means being disposed to engage said base plate; a carriage disposed on the opposite side of said base plate from said guide arms; means extending through said elongated opening to join said carriage to said first portion of said guide arm in order to minimize the bending of said first portion of said guide arm; and a curved electrode, said electrode being shaped to electrically discharge machine the concave portion of one nozzle blade and the adjacent convex portion of another nozzle blade as said electrode is fed into said nozzle block by said electrode guiding arm and said servo-motor.
Claim 3
Dependent Claim
25 words
An apparatus as set forth in claim 1, wherein the third portion of the electrode guide arm is electrically insulated from the second portion thereof.
Claim 4
Dependent Claim
29 words
Apparatus as set forth in claim 2, wherein the third portion of the electrode guide arm has an electrical cable connected thereto for supplying electrical power to the electrode.
Claim 5
Dependent Claim
26 words
Apparatus as set forth in claim 1, wherein the carriage has rolling means disposed thereon, and said rolling means is disposed to engage the base plate.
Claim 6
Dependent Claim
20 words
Apparatus as set froth in claim 4, wherein the rolling means disposed on said carriage comprises two diametricly disposed rollers.
Claim 7
Dependent Claim
43 words
Apparatus as set forth in claim 5, and further comprising biasing means which acts upon said carriage and said guide arm causing said rolling means to engage said base plate and thereby minimize the bending of said first portion of said guide arm.
Claim 8
Dependent Claim
14 words
Apparatus as set forth in claim 1, wherein the servo-motor is a hydraulic motor.
Claim 9
Dependent Claim
18 words
Apparatus as set forth in claim 1, wherein said first portion of said guide arm is generally L-shaped.
Claim 10
Dependent Claim
45 words
Apparatus as set forth in claim 8, wherein said L-shaped first portion of said guide arm has a base portion and a shank portion, the base portion being fastened to said shaft, and second portion of said guide arm being fastened to said shank portion.
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) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |