Chuck unit for automatic machine tools, designed to perform both power tasks and finishing work

A chuck unit comprising:

• first and second independent chucks mounted coaxially, one inside the other, and adapted to receive different tools, the chucks each having seating for the tools, which are coaxial and located on a same side of the chuck unit;
• first and second independent motors, for driving each of the respective first and second chucks;
• a support;
• a sleeve fixed to said support, wherein said first chuck is a power chuck and is fitted into said sleeve, and said second is a finishing chuck and is fitted inside said sleeve coaxially with and inside the power chuck;
• a shaft housed inside said finishing chuck fitted at one end with a tool cone gripper, wherein said shaft is pushed by springs, locking said gripper;
• a first bushing fitted to slide on said finishing chuck and driven by a independent motor of said finishing chuck;
• first elastic means for pushing the said first bushing in a direction in which said power chuck retracts;
• a second bushing fitted to slide on said finishing chuck;
• a first piston fitted inside said second bushing, wherein the end wall of said second bushing and one side of said first piston are engaged by second elastic means for pushing said first piston into a stop means fitted in a rear part of the chuck unit for stopping said elastic means and for pushing said second bushing into said first bushing, causing said first bushing to engage said power chuck, or a wall integral with said power chuck;
• and
• a means for engaging said shaft in order to control its displacement in relation to said first bushing, and cause said gripper fitted to said shaft to open and lock a cone of said tools inserted in the power chuck or finishing chuck.

A chuck unit comprising:

• first and second independent chucks mounted coaxially, one inside the other, and adapted to receive different tools, the chucks each having seating for the tools, which are coaxial and located on a same side of the chuck unit;
• first and second independent motors, for driving each of the respective first and second chucks;
• a first bushing slidably fitted on said second chuck which is a finishing chuck, wherein said first bushing is adapted to move between a resting position, where its front edge rests against a plate integral with said first chuck which is a power chuck, and a retracted position, where the first bushing retracts from said plate;
• a second bushing slidably fitted on a shaft behind said first bushing;
• a flange slidably fitted on said shaft, which is adapted to move between a position in which it approaches said second bushing and a position in which it moves away from said second bushing;
• a set of springs, located inside said second bushing, which displace said flange from said second bushing;
• a pair of ring-shaped pistons situated in chambers at opposite ends of a fixed stop;
• a piston fitted behind said second bushing for engaging said shaft on which said tool gripper is fitted;
• and
• pump means for pumping a pressurized fluid into said chambers in which the ring-shaped pistons are situated, pushing said pair of pistons toward one another, and causing one of said pistons to engage said fixed stop and the other piston to engage said second bushing, thus positioning flange.