Patent ID: 8684364

Claim:
An arbor of a machine tool comprising: a collet arbor base, an expandable and releasable collet for engaging and releasing from a subject gear, said collet having a top band coupled over a length of the collet to a bottom band thereof, an actuator pin slidable upward and downward from the collet arbor base arranged concentrically within the collet and having a reverse male taper on an upper end thereof that actuates the top band of the collet, a conical ring having a larger root diameter tapering to a smaller ring diameter with a taper angle matching the upper end of the actuator pin arranged proximate a lower part of the actuator pin concentrically therewith for actuating the bottom band of the collet, a spring provided on an upper surface of the collet arbor base and configured to push against a lower end of the bottom band of the collet to bias it for an elastic anti-backlash movement, a spacer disc mounted on an upper surface of the collet arbor base having a retentive flange that is used to stop upward movement of the collet by a stopper lip thereof which defines the upper limit of release movement of the collet while allowing elements of the bottom band of the expanding collet to move radially and perpendicularly with respect to the arbor thereby preventing the bottom band from locking onto the subject gear or the larger root diameter of the conical ring inside the collet's bottom band, wherein when the actuator pin is displaced axially downward, the reverse male taper of the upper end of the actuator pin pushes the top band downward to expand it outward, while the bottom band expands outward when the collet is pushed by the actuator pin's downward displacement on the matching taper of the conical ring, and wherein when the actuator pin is displaced axially upward, the reverse male taper positively releases from the top band of the collet, and the bottom band of the collet is positively released from the taper of the conical ring, whereby movement of the actuator pin axially upward and downward causes the collet to positively expand and retract accordingly, and in its positive retraction ensure positive release of the collet from keeping locked onto a subject gear.