Workpiece holder for a vertical broaching machine for broaching annular workpieces

A workpiece holder for a vertical broaching machine for broaching annular workpieces in a sequence of steps without removing the workpiece from the holder, the holder comprising:

• a baseplate having serrations on one surface thereof;
• a workpiece support means, rotatably disposed relative to said baseplate, for axial location of the workpiece;
• a piston, nonrotatably connected to said workpiece support means, and having serrations, complementary to the serrations on said baseplate, on one surface thereof facing the surface of said baseplate on which are the serrations thereof;
• a cylinder in which said piston is rotatably and axially displaceably disposed between two axial end positions, the serrations on said piston being in engagement with the serrations on said baseplate, thereby holding said piston centered and nonrotatable, at the first end position and said serrations being out of engagement at the second end position;
• a first chamber means delimited by said serrations for receiving pressure oil which forces said piston to the second position thereof when it is desired for said serration to be out of engagement;
• a second chamber means formed between said piston and said cylinder for receiving pressure oil which forces said piston to the first position thereof when it is desired for said serration to be in engagement;
• and
• tensioning means for radial location and centering of the workpiece within said workpiece support means, and wherein said tensioning means includes a tensioning ring screwed into said support means from above, and a tensioning sleeve, connected to said tensioning ring, abutting the outer surface of the workpiece at the inner tightening surface of said sleeve and abutting a frustoconically tapering surface of said workpiece support means at the outside surface of said sleeve, whereby screwing of said tensioning ring into said workpiece support means causes said tensioning sleeve to firmly connect the workpiece to said workpiece support means in a centered position with respect thereto.