Clamping chuck for a machine tool, especially an automatic machine tool, and a method for preparing it

A clamping chuck for a machine tool, comprising:

• a body, having a substantially cylindrical shape, said body having a rear frontal face configured to be fixed to the machine tool and an anterior frontal face directed towards a workpiece to be clamped, and having lateral walls defining radial cuts opening onto the anterior frontal face, the lateral walls comprising a plurality of first radial slideways having first frontal sliding surfaces,
• jaw holders, for carrying clamping jaws, part of said jaw holders being configured to be engaged in one of the radial cuts, the part having two circumferentially opposed faces, and having on each of the two circumferentially opposed faces at least two second slideways having second frontal sliding surfaces for interacting with the first sliding surface, to guide the jaw holder radially,
• control members placed in said body and able simultaneously to displace said jaw holders in the direction of a workpiece to be clamped, and to apply a predetermined radial clamping force to said jaw holders,
• this force having the result that the first and second sliding surfaces are displaced axially relative to said body and to said jaw holder respectively, following an elastic deformation of the first radial slideways and second slideways,
• the flexibility of the first radial slideways and second slideways being calculated and chosen so that the axial displacements of the first sliding surfaces and the second sliding surfaces are greater than the spreads which may exist between the axial distances separating two first sliding surfaces and two second sliding surfaces, wherein these spreads are the result of machining tolerances.