1. Field of the Invention
The present invention relates generally to tool chuck assemblies, such as in particular those adapted to rigidly clamp workpieces exhibiting thin wall cross sections. More specifically, the present invention discloses an improved tool part locking chuck exhibiting a plurality of independent and circumferentially arrayed wedge clamps for gripping selected locations of an irregular and often thin walled workpiece. The chuck holder may incorporate multiple spring, pneumatic or hydraulic clamping pressure, uniformly spread across all of the circumferentially arrayed wedge clamps, and with the effect of both increasing the amount of contact points (and corresponding clamping pressure) concurrent with reducing or eliminating part deformation.
2. Description of the Prior Art
The prior art is well documented with varying types of lathe chuck holding assemblies, such as which are associated with a rotary driven and spindle supported assembly for permitting a stationary positioned tool to machine given surfaces associated with a clamped workpiece. A first example is set forth in U.S. Pat. No. 6,464,235, issued to Rohm, and which teaches a latch chuck having a chuck body centered on and rotatable about a main axis. The chuck is formed with a plurality of radially extending jaw-guide grooves and, transverse to the grooves, with respective guide passages each in turn formed with an abutment. Respective jaws are displaceable in the grooves with each having at least one tooth exposed in the respective guide passage and respective control rods displaceable along the passages each having at least one tooth meshing with the tooth of the respective jaw. A control pin is axially displaceable in each rod between an extended position projecting into the respective jaw-guide groove and a retracted position. A latch pin is axially displaceable in each rod between an extended latching position engaging the respective rod in the respective passage and a retracted position permitting such movement. A spring urges the pins into their extended positions, and a coupling member engaged between the pins displaces the respective latch pin into the respective retracted position on displacement of the control pin into its retracted position. Thus, when there is no jaw in the guide groove, the latch pin of the respective control rod latches the same against movement in the respective passage.
U.S. Pat. No. 4,026,566, also issued to Rohm, teaches a chuck for latches and other machine tools having a chuck body provided with axially shiftable wedging members to actuate the jaws, a rotatable guard ring prevents full axial withdrawal of these members from sockets in the jaws in one angular position of the ring. In another angular position of the ring, recesses in the latter are aligned with the wedging members to allow the latter to clear the jaws for radial withdrawal and replacement thereof.
Japanese Patent Publication JP2001/038510 teaches a machine tool chuck exhibiting a pair of movable wedge bars driving a plurality of clamp jaws arranged inside a guide notch of radial direction of a chuck body and intersecting the guide notch inside a wedge bar picket inside the chuck body to form worm gears with rows of gear teeth meshing with corresponding gear cut groove parts of the clamp jaws. A lock slider is incorporated in each wedge bar with a lock pin rod movably guided in parallel to a chuck axis arranged therein. A plurality of lock sliders are capable of moving the lock pin rods having the rows of gear teeth from a lock position maintaining an engaged state with the clamp jaws to an exchange position enabling exchange of the clamp jaws. In such a case, securing pin rods are movable in the axial direction, receiving the force of the springs and being pressed toward the clamp jaws arranged inside the lock pin rods.
U.S. Pat. No. 5,158,307, issued to Toyano et al., teaches a machine tool chuck in which a wedge member is provided to cause radial displacement or workpiece clamping pawls for replacement. The replacement can be made with minimum variations in radial position at which the clamping pawls are relocated. To this end, the clamping pawls and slide blocks are slidably guided radially through a chuck body independently of each other. Each clamping pawl and each slide block are in slidable engagement with a sloping wedge action portion of an axial slidable wedge bar in such a way that the clamping pawl and slide block move radially independently of each other while maintaining a geometric relationship there between. For replacement of the clamping pawl, the wedge bar is moved backward to cause its wedge action portion to be disengaged from the clamping pawl whereby the clamping pawl can be slid radially outwardly for replacement.
Finally, U.S. Pat. No. 4,799,837, issued to Vollmer, teaches a multi-component chucking system, in particular for concentric or true rotation tools, and having a receiving body optionally having a chucking shaft, with an engagement surface extending at right angles to the axis of rotation and a coaxial retention bore as well as a tool element, preferably embodied as a tool holder. On its end face, the tool element also has an engagement surface at right angles to the axis of rotation and is formed with a coaxial retention stub fitting into the retention bore, by means of which stub the tool element can be centered with respect to the receiving body. A chucking pin is associated with the retention stub and coaxial with the axis of rotation, along with chucking means actuable from outside the receiving body, allowing the clamping together of the tool element and the receiving body. The chucking means have two radially movably supported locking elements which have locking surfaces by which, in a chucking position, wedge-like surface regions of the chucking pin that are inclined with respect to the axis of rotation are engaged from below. These wedge-like surface regions of the chucking pin are located on a single common conical surface region that is coaxial with the axis of rotation and forms an acute angle with it.