Numerically controlled orbital machining apparatus

An orbital machining apparatus for producing a hole in a workpiece by means of a cutting tool, said apparatus comprising:

• a first actuator configured for rotating the cutting tool about its longitudinal center axis during the machining of the hole;
• a second actuator configured for moving the cutting tool in an axial feed direction substantially parallel to said cutting tool longitudinal center axis, said second actuator being simultaneously operable with said first actuator;
• a third actuator configured for rotating the cutting tool about a principal axis, said principal axis being substantially parallel to said longitudinal center axis of the tool and coaxial with a longitudinal center axis of the hole to be machined, said third actuator being simultaneously operable with said first and second actuators;
• and
• a radial offset mechanism configured for controlling a radial distance of said longitudinal center axis of the cutting tool from said principal axis, said radial offset mechanism comprising:
• an inner cylindrical body having an eccentric cylindrical hole, said eccentric cylindrical hole having a longitudinal center axis that is parallel to and radially offset from a longitudinal center axis of said inner cylindrical body, said eccentric hole being configured to radially and rotatably support a spindle unit for operating said cutting tool;
• and
• an outer cylindrical body having an eccentric cylindrical hole, said eccentric cylindrical hole of said outer cylindrical body having a longitudinal center axis that is parallel to and radially offset from a longitudinal center axis of said outer cylindrical body, said inner cylindrical body being radially supported in said eccentric cylindrical hole of the outer cylindrical body and rotatable therein so as to adjust the radial distance of said longitudinal center axis of the cutting tool from said principal axis;
• said third actuator including both a first motor drivingly connected to said outer cylindrical body for individually rotating said outer cylindrical body about said longitudinal center axis of said outer cylindrical body, and a second motor drivingly connected to said inner cylindrical body for individually rotating said inner cylindrical body about said longitudinal center axis of said inner cylindrical body, both said first motor and said second motor being able to rotate said outer cylindrical body and said inner cylindrical body, respectively, in synchronism to maintain a mutual rotary position thereof to keep a radial offset position of the cutting tool unchanged during a working operation.