# US 4,398,350 A · Centering controller for a tool electrode on an electrical machine tool

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- Number: US 4,398,350 A
- Document ID: US4398350A
- Status: Granted
- Kind: A
- Application number: 06/230,104
- Filed: 1981-01-29
- Granted: 1983-08-16
- Earliest claimed: 1981-01-29
- Assignees: Inoue-Japax Research Incorporated
- Inventors: Kiyoshi Inoue
- Web page: https://patentgrep.com/patent/US4398350A

## CPC

- G01B 7/31: for testing the alignment of axes
- B23H 7/26: Apparatus for moving or positioning electrode relatively to workpiece; Mounting of electrode
- B23Q 1/28: Means for securing sliding members in any desired position
- B23Q 1/545: {comprising spherical surfaces}
- B23Q 3/18: for positioning only
- B23Q 15/22: Control or regulation of position of tool or workpiece
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- B23H: WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL (processes for the electrolytic or electrophoretic production of coatings, electroforming, or apparatus therefor C25D; processes for the electrolytic removal of material from objects C25F; manufacturing printed circuits using precipitation techniques to apply the conductive material to form the desired conductive pattern H05K3/18)
- B23Q: DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING (tools of the kind used in lathes or boring machines B23B27/00); MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT

## Abstract

A positioning device for a tool electrode on an electrical machine tool, comprising: a tool head and a swivel electrode support for securely holding the tool electrode and adapted to be swivelably carried by the tool head whereby to allow the axis of the tool electrode to be swung relative to the tool head about a fulcrum lying on the axis of the latter. An electrode centering assembly is used to align the axis of the tool electrode with the axis of the tool head and comprises a plurality of axial drive units operative for displacement and pressurization along the respective radially equi-spaced axes, each unit comprising a pressure plate having a pressure surface extending in parallel with the axis of the tool head and slidably received in a casing and resiliently supported thereby to maintain the parallelism. Motors are used to conjointly advance the casings to displace the pressure plates towards and urge them against the tool electrode. The parallel surfaces of the pressure plates urged against the tool electrode thus rotate the latter about the fulcrum to bring it parallel with the pressure surfaces and hence into a precise axial alignment with the tool head. Support retainer means is coupled to the tool head and actuatable, after establishment of the axial alignment or parallelism, to fixedly secure the swivel electrode support to the tool head.

## Claims

### Claim 1

A positioning device for orienting an axial member so as to be precisely in alignment with a predetermined axial direction, comprising:
a head member having an axis conciding with said predetermined directions;
a swivel support for securely holding said axial member, said support being adapted to be swivelably carried by said head member whereby to allow the axis of said axial member to be swung about a center of swing relative to said axis of the head member;
centering means comprising:
a plurality of casings which are displaceable, in a plane, along a plurality of axes, respectively, which are orthogonal to and equispaced radially about, said axis of the head member,
a plurality of pressure plates which have their respective pressure surfaces extending in parallel with said axis of the head member and which are received slidably and supported resiliently by elastic means, in said respective casings so as to maintain said respective parallelisms, and
means for advancing said casings respectively towards said axial member to allow said respective pressure plates to bear along said pressure surfaces against said axial member individually and then to conjointly come into pressure engagement therewith until after the pressures exerted by said respective elastic means via said respective plates on said axial member are equalized; and
support retainer means coupled to said head member and adapted to be actuated, after said equalization of the pressure by said elastic means, to fixedly secure said swivel support to said head member.

### Claim 2 (depends on 1)

The device defined in claim 1 wherein said advancing means comprises:
a plurality of motors for advancing said casings respectively;
a drive circuit for supplying drive signals to said motors to conjointly advance said casings;
a contact sensor associated with each of said pressure plates for providing an electrical signal upon each of said pressure plates coming into a predetermined pressure engagement with said axial member; and
a control circuit responsive to development of such electrical signals by all of said contact sensors for acting on said drive circuit for said motors to move said casings by a predetermined equal distance to hold with said pressure surfaces said axial member centered in alignment with said axis of the head member, whereafter permitting said support retainer means to fixedly secure said swivel support to said head member.

### Claim 3

A positioning device for orienting an axial member so as to be precisely in alignment with a predetermined axial direction, comprising:
a head member having an axis coinciding with said predetermined direction;
a swivel support for securely holding said axial member, said support being adapted to be swivelably carried by said head member whereby to allow the axis of said axial member to be swung about a center of swing relative to said axis of the head member, said swivel support having at one end portion thereof a fulcrum member in the form of a sphere defining at its center said center of swing and having the other end portion thereof secured to said axial member to permit the latter to be swung, said fulcrum member being slidably received in a support surface therefor of said head member;
centering means adapted for engagement with said axial member for positioning said axial member in an axial alignment with said axis of the head member intersecting said center of swing of said head member; and
support retainer means coupled to said head member and adapted to be actuated, after establishment of said axial alignment of the axial member with said axis of the head member, to fixedly secure said swivel support to said head member, said retainer means comprising a powder of ferromagnetic particles disposed to fill at least a portion of the spacing between said fulcrum member and said support surface of the head member and coil means energizable by a power supply to magnetically consolidate said powder of ferromagnetic particles, thereby frictionally clamping said fulcrum member to said support surface and deenergizable to release said frictional clamping.

### Claim 4 (depends on 3)

The device defined in claim 3 wherein said retainer means further comprises bearing means between said fulcrum member and said support surface for preventing said powder from flowing out of said spacing when said coil means is de-energized.

### Claim 5

A positioning device for orienting an axial member so as to be precisely in alignment with a predetermined axial direction, comprising:
a head member having an axis coinciding with said predetermined directions;
a swivel support for securely holding said axial member, said support being adapted to be swivelably carried by said head member whereby to allow the axis of said axial member to be swung about a center of swing, relative to said axis of the head member, said swivel support having at one end portion thereof a fulcrum member in the form of a sphere defining at its center said center of swing and having the other end portion thereof secured to said axial member to permit the latter to be swung, said fulcrum member being slidably received in a support surface therefor of said head member;
centering means adapted for engagement with said axial member for positioning said axial member in an axial alignment with said axis of the head member intersecting said center of swing of said head member; and
support retainer means coupled to said head member and adapted to be actuated, after establishment of said axial alignment of the axial member with said axis of the head member, to fixedly secure said swivel support to said head member, said retainer means comprising a frictional pad secured to an armature resiliently supported on said support surface by spring means of press said frictional pad against said fulcrum member, thereby holding the latter to said head member, and solenoid means operatively associated with said armature against said spring means to disengage said frictional pad from said fulcrum member, thereby releasing said swivel support from said head member.

### Claim 6 (depends on 1, 2)

The device defined in claim 1 or claim 2 wherein said pressure surfaces of said pressure plates are individually comb-shaped longitudinally of said axial member with teeth of one such plate surface being arranged to be transverse to those of such plate surfaces adjacent thereto to permit them to be advanced in engagement and without interference with each other.

### Claim 7 (depends on 2)

The device defined in claim 2 wherein said swivel support has at one end portion thereof a fulcrum member in the form of a sphere defining at its center said center of swing and has the other end portion thereof secured to said axial member to permit the latter to be swung.

### Claim 8 (depends on 7)

The device defined in claim 7 wherein said fulcrum member is slidably received in a support surface therefor of said head member.

### Claim 9 (depends on 8)

The device defined in claim 8 wherein said retainer means comprises a powder of ferromagnetic particles disposed to fill at least a portion of the spacing between said fulcrum member and said support surface of the head member and coil means energizable by a power supply to magnetically consolidate said powder of ferromagnetic particles, thereby frictionally clamping said fulcrum member to said support surface and de-energizable to release said frictional clamping.

### Claim 10 (depends on 9)

The device defined in claim 9 wherein said retainer means further comprises bearing means between said fulcrum member and said support surface for preventing said powder from flowing out of said spacing when said coil means is de-energized.

### Claim 11 (depends on 8)

The device defined in claim 8 wherein said retainer means comprises a frictional pad secured to an armature resiliently supported on said support surface by means of a spring means to press said frictional pad against said fulcrum member, thereby holding the latter to said head member and a solenoid means operatively associated with said armature and energizable by a power supply to retract said armature against said spring means to disengage said frictional pad from said fulcrum member, thereby releasing said swivel support from said head member.