Machine tool with fluid actuated helical adjustment of abrasive elements

An adjustment mechanism for a tool used on a machine, said machine having a drive spindle for connection to said tool, said tool having a plurality of abrasive elements mounted on the tool for radial movement with respect to the tool, said adjustment mechanism comprising:

• an adjustment assembly mounted within said tool in engagement with said abrasive elements to convert an axial force to a radial force to actuate said radial movement of the abrasive elements;
• a chamber formed in said tool;
• a fluid connection for supplying fluid under pressure to said chamber;
• a piston mounted for axial movement in said chamber, wherein said fluid acts on said piston to provide axial movement thereof, wherein said piston is mounted to rotate as it moves axially;
• an adjustment rod mounted within said tool and connected to said piston in a manner which transmits only rotary motion to said adjustment rod in response to movement of said piston;
• rotation limiting means mounted in said tool for engagement with the adjustment rod to allow rotation thereof in a single rotational direction, said rotational direction causing expansion of the abrasive elements;
• and
• wherein said adjustment rod is connected to the adjustment assembly by means which convert the rotation of the adjustment rod to an axial force to actuate radial movement of the abrasive elements.