US4476369A — EDM Method of and apparatus for machining cavitie…

Claim 1

Independent Claim 153 words

An EDM method of machining the surfaces of a cavity in an electrically conductive workpiece, the method comprising the steps of: (a) bringing at least partially into a cavity in an electrically conductive workpiece an electrode assembly comprising a plurality of segmented electrodes having their respective machining surfaces which collectively form a contour corresponding in shape to said cavity, said segmented electrodes being supported so as to be generally spaced apart and movable relative to each other in said assembly; and (b) electrically energizing said segmented electrodes individually with respect to said workpiece while individually displacing said segmented electrodes, generally independently of one another, relative to said workpiece, along respective predetermined paths of translational motion, thereby permitting electrical discharges to develop between each of said surfaces of the cavity and the machining surface of each of said segmented electrodes brought proximate thereto across a fluid-filled machining gap during said individual translational motion thereof.

Claim 2

Dependent Claim 153 words

An EDM method of machining the surfaces of a cavity in an electrically conductive workpiece, the method comprising the steps of: (a) bringing at least partially into a cavity in an electrically conductive workpiece an electrode assembly comprising a plurality of segmented electrodes having their respective machining surfaces which collectively form a contour corresponding in shape to said cavity, said segmented electrodes being supported so as to be generally spaced apart and movable relative to each other in said assembly; and (b) electrically energizing said segmented electrodes individually with respect to said workpiece while individually displacing said segmented electrodes, generally independently of one another, relative to said workpiece, along respective predetermined paths of translational motion, thereby permitting electrical discharges to develop between each of said surfaces of the cavity and the machining surface of each of said segmented electrodes brought proximate thereto across a fluid-filled machining gap during said individual translational motion thereof.

Claim 3

Dependent Claim 39 words

The method defined in claim 1 wherein said segmented electrodes are individually displaced in step (b) along said respective paths which lie in a plane substantially orthogonal to the direction in which said assembly is brought in step (a).

Claim 4

Dependent Claim 36 words

The method defined in claim 2 wherein said assembly is brought in step (a) by machining by electrical discharges said cavity in said workpiece while relatively displacing said electrode assembly electrode and said electrically conductive workpiece.

Claim 5

Dependent Claim 49 words

The method defined in claim 1, further comprising: in step (b) the step of controlling the respective amplitudes of the translational movements of said segmented electrodes in accordance with the particular geometrical characteristics of those portions of the cavity with which they are juxtaposed across their respective machining gaps.

Claim 6

Dependent Claim 72 words

The method defined in claim 4 wherein said portions include a relatively smooth stoping region and a region which is relatively intricate in shape, comprising: in step (b) translationally displacing that of said segmented electrodes which is juxtaposed with the former region with a first amplitude while translationally displacing that of said segmented electrodes which is juxtaposed with the latter region with a second amplitude which is smaller than said first amplitude.

Claim 7

Dependent Claim 30 words

The method defined in claim 1, further comprising: in step (b) servo-controlling the positions of said segmented electrodes, independently from one another, in response to their respective machining gap conditions.

Claim 8

Dependent Claim 30 words

The method defined in claim 4, further comprising: in step (b) servo-controlling the positions of said segmented electrodes, independently from one another, in response to their respective machining gap conditions.

Claim 9

Dependent Claim 148 words

An EDM apparatus for machining the surfaces of a cavity in an electrically conductive workpiece, the apparatus comprising: an electrode assembly comprising a plurality of segmented electrodes having their respective machining surfaces which collectively form a contour corresponding in shape to a cavity, said segmented electrodes being supported so as to be generally spaced apart and movable relative to each other in said assembly; power supply means for electrically energizing said segmented electrodes individually with respect to said workpiece; and a plurality of drive means operable independently of one another for individually displacing said segmented electrodes, generally independently of one another, relative to said workpiece, along respective predetermined paths of translational motion, whereby electrical discharges develop between each of said surfaces of the cavity and the machining surface of each of said segmented electrodes brought proximate thereto across a fluid-filled machining gap during said individual translational motion thereof.

Claim 10

Dependent Claim 148 words

An EDM apparatus for machining the surfaces of a cavity in an electrically conductive workpiece, the apparatus comprising: an electrode assembly comprising a plurality of segmented electrodes having their respective machining surfaces which collectively form a contour corresponding in shape to a cavity, said segmented electrodes being supported so as to be generally spaced apart and movable relative to each other in said assembly; power supply means for electrically energizing said segmented electrodes individually with respect to said workpiece; and a plurality of drive means operable independently of one another for individually displacing said segmented electrodes, generally independently of one another, relative to said workpiece, along respective predetermined paths of translational motion, whereby electrical discharges develop between each of said surfaces of the cavity and the machining surface of each of said segmented electrodes brought proximate thereto across a fluid-filled machining gap during said individual translational motion thereof.

Claim 11

Dependent Claim 60 words

The apparatus defined in claim 8 wherein said electrode assembly is carried by a spindle so as to be movable in the direction of its axis to machine said cavity in said workpiece and said drive means are adapted to translation displace said segmented electrodes individually along said predetermined paths which lie in a plane substantially orthogonal to said direction.

Claim 12

Dependent Claim 37 words

The apparatus defined in claim 9 wherein said segmented electrodes comprise an outer electrode segment which is arranged about said axis and an inner electrode segment which is surrounded by said outer electrode segment across a spacing.

Claim 13

Dependent Claim 57 words

The apparatus defined in claim 10 wherein said outer and inner electrode segments are securely carried by first and second support members, respectively, in said electrode assembly and said plural drive means include a first pair of motors and a second pair of motors which pairs are drivingly coupled with said first and second support members, respectively.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1987-10-09	1988-04-09	1988-10-09	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1991-10-09	1992-04-09	1992-10-09	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1995-10-09	1996-04-09	1996-10-09	$7700.00	Window Closed / Lapsed

EDM Method of and apparatus for machining cavities using a plurality of independently movable segmented electrodes

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