Centering controller for a tool electrode on an electrical machine tool

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.

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.