Grinding machine for grinding tripods of constant velocity couplings

A grinding machine for executing, on each of a plurality of elements of a workpiece, a circular profile or a profile having points which are not at the same distance from an element axis, the machine comprising:

• a workhead with supporting and holding means for supporting and holding a workpiece during working and for moving the workpiece for execution of a desired profile including rotating the workpiece about an axis of the element being worked for obtaining a circular profile and rocking the piece to periodically vary a distance of said element from said grinding wheel for obtaining a profile with points which are not at a same distance from the axis of the element being worked, a grinding wheel, said support and holding means including
• an arbor,
• a body carried by said arbor for imparting rotational movement to the workpiece about an axis coinciding with the axis of the element being worked, said body including a seat,
• a receiving member for receiving the workpiece, said receiving member being positioned in said seat of said body and including a longitudinal axis perpendicular to a rotation axis of said body, said receiving member being axially displaceable between a first position said receiving member assumes during execution of a profile on one workpiece element of the workpiece and a second position in to which said receiving member is moved at an end of profile execution on said element,
• receiving member actuation means for displacing said receiving member between said first position and said second position,
• rotation means for rotating said receiving member about an axis of said receiving member while said receiving member is in said second position to bring another element of the workpiece to a working position,
• stop means for preventing rotation of said receiving member in said first position,
• a workpiece holding member, positioned in an axial cavity of said receiving member and cooperating with retaining elements for retaining the workpiece on said receiving member, said workpiece holding member being axially slidable in said cavity between a first position for working on the workpiece, wherein the retaining elements are in engagement with the workpiece, and a second position for allowing insertion of the workpiece and removal of the workpiece, wherein the retaining elements are out of engagements with the workpiece,
• a resilient member fastened to said workhead and fastened to a stationary portion of said grinding machine, said resilient member being bendable with respect to a bending axis parallel to the axis of the element being worked on, said resilient member having a size in the direction perpendicular to the axis of the element being worked on so as to prevent contact between said workhead and said stationary portion of said grinding machine in a maximum bending condition, said bending axis lying in a gap separating said workhead from said stationary portion of said grinding machine, and
• a piezoelectric transducer, mounted between said workhead and said stationary portion of said grinding machine and having a length which is periodically varied to cause bending of said resilient member and rocking of said workhead to vary a distance of the element being worked from said bending axis.