Machine for the two-stage machining of preground shafts

A machine for a two-stage machining of preground shafts, especially automotive crankshafts, comprising:

• a pair of levers fulcrummed to enable free ends of said levers to be displaced toward and away from an axis of a workpiece disposed between said ends;
• respective actuators connected with said levers for displacing same;
• a programming unit operatively connected with said actuators for controlling machining of said workpiece;
• respective tools on said ends of said levers engageable with said workpiece for effecting one stage of a two-stage machining process under control of said unit, said two-stage machining process including a pre-finish grinding and a fine-finish grinding;
• and
• a tool-carrier tongs insertable between said ends into said pair of levers and retractable from between said ends, said tongs comprising:
• a carrier,
• a pair of arms articulated to said carrier and having free ends respectively coupled to said ends of said levers upon insertion of the tool-carrier tongs between the ends of said levers,
• respective restoring springs on said carrier braced against said arms whereby said arms are movable under control of said unit against said springs, and
• respective tools carried by said arms and engageable with said workpiece for effecting the other of said stages of the two-stage machining of the workpiece.