Hydraulic ring chuck

Claim 1

In a compensating chuck construction for supporting a workpiece and particularly for supporting a ringlike workpiece to permit machining of all surfaces thereof, said chuck construction including a housing defining a longitudinally extending axis and having an end face disposed to face said workpiece, and inner and outer jaw systems movably supported on said housing for engaging said workpiece and supporting same adjacent said end wall, comprising the improvement wherein: said inner jaw system includes a. a plurality of first recesses formed in said housing and angularly spaced around the axis thereof, each of said recesses extending on a first direction which is inclined at a small angle relative to said axis and converges with respect to said axis as said recess extends inwardly into said housing away from said end face, b. a plurality of first jaw carriers slidably mounted on said housing for sliding movement between an inoperative position wherein the jaw carriers are out of engagement with a workpiece and an operative position wherein the jaw carriers are disposed in engagement with the workpiece, one of said first jaw carriers being slidably supported within each of said first recesses and being movable in said first direction whereby each of said first jaw carrier is self-holding relative to said housing when engaged with said workpiece, each of said first jaw carriers having an end portion thereof projecting outwardly of said housing beyond said end face and having a workpiece-engaging jaw associated therewith, said workpiece-engaging jaw being movable axially away from said end face and radially outwardly away from said axis as said firsT jaw carrier is slidably moved from said inoperative position toward said operative position, c. first piston means associated with each of said first jaw carriers for causing slidable movement thereof from said inoperative position to said operative position; said outer jaw system including a. a plurality of second recesses formed in said housing and angularly spaced around said axis, said plurality of second recesses being concentric with and spaced radially outwardly from said plurality of first recesses, each of said second recesses extending in a second direction which is inclined at a small angle relative to said axis and which diverges relative to said axis as said recess extends inwardly into said housing away from said end wall, b. a plurality of second jaw carriers slidably supported on said housing for sliding movement between an inoperative position wherein said second jaw carriers are out of engagement with a workpiece and an operative position wherein said second jaw carriers are disposed in engagement with the workpiece, one of said second jaw carriers being slidably supported within each of said second recesses and being movable in said second direction whereby each said second jaw carrier is self holding relative to said housing when engaged with said workpiece, each of said second jaw carriers including an end portion projecting from said housing outwardly beyond said end wall and having a workpiece-engaging jaw mounted thereon, said workpiece-engaging jaw being movable axially away from said end wall and radially inwardly relative to said axis as said second jaw carrier is slidably moved from said inoperative position toward said operative position, c. second piston means associated with each of said second jaw carriers for causing slidable movement thereof from said inoperative position toward said operative position; first fluid passage means providing a common fluid connection between the plurality of first piston means for permitting pressure fluid to be supplied to said first piston means and for permitting relative movement between said first piston means to enable said first jaw carriers to compensate for workpiece eccentricity; and second fluid passage means providing a common fluid connection between the plurality of second piston means for causing movement of said second piston means and for permitting relative movement between said second piston means to enable said plurality of second jaw carriers to compensate for workpiece eccentricity; the workpiece-engaging jaws associated with said plurality of first jaw carriers being spaced outwardly from said end wall when in said operative position, and the workpiece-engaging jaws associated with said plurality of second jaw carriers also being spaced outwardly from said end wall when in said operative position, whereby said workpiece can be rigidly supported in spaced relationship from said end wall for permitting all surfaces thereof to be machined.