Apparatus for automated peening of tenons connecting turbine buckets and cover plates

The present invention relates to an automated peening tool for automatically peening the tenons of cover plates to secure the cover plates and adjacent tips of turbine buckets to one another and to methods for peening the tenons for connecting the cover plates and buckets to one another. An automatic machine for peening the tenons on bucket cover plates to secure the cover plates and adjacent buckets of a turbine wheel to one another is provided. The machine includes a fixture having stepped surfaces for locating the freely suspended fixture and peening tool relative to the bucket tips and cover plates and clamping the tips and cover plates to the fixture surfaces. After peening a first tenon, the fixture and tool head are displaced relative to the fixed cover plate and bucket tip to register the tool with a second tenon. An actuator displaces the suspended system to compensate for the movement of the fixture and tool relative to the turbine wheel. A counterbalance is provided to accommodate fixtures of different weights when peening the tenons of covers in different turbine wheels.