Apparatus and method for centering a workpiece on a machine tool

Apparatus for centering a workpiece on a machine tool, comprising:

• (a) first and second guide plates having respective first and second aligned bores therein for supporting a centering pin mounted therein for axial movement between a retracted position and a use position;
• (b) at least one spring cooperating with the centering pin for exerting a predetermined axial bias for urging the centering pin into the use position;
• and
• (c) a lock for locking the centering pin in the use position.

An apparatus for centering a workpiece on a metal milling fixture, comprising:

• (a) first and second guide plates having respective first and second aligned bores therein for supporting a centering pin mounted therein for axial movement between a retracted position and a use position, wherein the centering pin cooperates with a workpiece for positioning the workpiece in a predetermined position relative to the fixture;
• (b) at least one flat, triple beam spring cooperating with a rear end of the centering pin for exerting a predetermined axial bias for urging the centering pin in a forward direction into the use position;
• and
• (c) a lock for locking the centering pin in the use position.

Apparatus for centering a turbine engine blade on a metal milling fixture, comprising:

• (a) first and second guide plates having respective first and second aligned bores therein for supporting a centering pin mounted therein for axial movement between a retracted position and a use position, wherein the centering pin cooperates with a blade for positioning the blade in a predetermined position relative to the fixture;
• (b) at least one flat, triple beam spring cooperating with a rear end of the centering pin for exerting a predetermined axial bias for urging the centering pin in a forward direction into the use position;
• (c) a tip mounting block having an angled inset matching a taper on a front end of the centering pin for being received therein, and a blade-receiving slot in the tip mounting block for being positioned on an end of the blade to be supported in a fixed position during milling;
• (d) a locking strap extended over the top of the centering pin from one radial side to the other and moveable between a release position allowing axial movement of the centering pin and a lock position for locking the centering pin in the use position;
• and
• (e) a hydraulic cylinder operatively connected to one end of the locking strap for selectively moving the strap between a release position wherein the centering pin is axially moveable and the lock position.

A method for centering a workpiece on a metal shaping machine, comprising the steps of:

• (a) providing first and second guide plates having respective first and second aligned bores therein for supporting a centering pin mounted therein for axial movement between a retracted position and a use position;
• (b) engaging at least one spring with the centering pin for exerting a predetermined axial bias against the centering pin in the direction of the workpiece for urging the centering pin into the use position;
• and
• (c) locking the centering pin in the use position during the operation of the machine on the workpiece.