Patent Description:
While these types of active flexible tooling systems addressed certain problems associated with non-universal tooling, in many cases they have proven unreliable, particularly in wet environments such as waterjet cutting of composite workpieces. Common malfunctions include complete operational failure of individual actuators, which may be visually apparent and can be addressed by replacing the malfunctioning actuator. Even greater complications may occur when actuators misposition with amounts too small for visual detection, resulting in workpieces being machined out of tolerance.

Most known flexible tooling systems utilize workpiece engaging end effectors which pivot freely, making position detection and verification by automated methods impossible. The resulting conundrum is that these systems may not always position properly, and there is no good way to tell if that has happened.

The present invention utilizes configurable workpiece support assemblies that are designed to provide accurate and verifiable support of workpieces. Exposure to water, even for extended periods of time will have no effect on the performance of the present invention since the workpiece support assemblies contain no electronic components, motors or valves. The present invention incorporates fully immobilized fixture elements, allowing automated position verification and qualification to be performed with known devices including spindle probes, coordinate measuring machines and laser scanning systems.

The invention is directed to a workpiece support assembly. The assembly comprises a pedestal, a support tube, an offset arm, and a fixture element. The support tube is carried by the pedestal and has a longitudinal axis. The offset arm is carried by the support tube and selectively rotatable about the longitudinal axis. The arm has a rectilinear channel formed therein. The fixture element is supported above the channel and movable along a line parallel thereto. The fixture element has at least two degrees of rotational freedom.

In another aspect, the invention is directed to a system. The system comprises a plurality of unpowered support assemblies and a robotic unit. Each support assembly has a fixture element that has at least five selectable degrees of kinematic freedom. The robotic unit is positionable in operative engagement with each of the plurality of support assemblies. The robotic unit carries one or more installation elements collectively having at least five degrees of kinematic freedom.

The present invention consists of a plurality of workpiece support assemblies which are mounted to a common table structure. Each workpiece support assembly carries a fixture element, together with a means to provide vacuum to hold the workpiece against the fixture element. Each fixture element can be adjusted with up to six degrees of kinematic freedom, and then immobilized rigidly in the desired position with extreme precision. At the heart of the invention are a combination of joints, slides and pivots, which, working in concert, provide an unprecedented freedom of movement, while retaining the capability for the workpiece engaging surface to be immobilized securely in a practically unlimited number of positions.

Prior tooling systems of the types disclosed in <CIT> and <CIT> are commonly used in the aerospace industry. The workpiece support assemblies in these systems are typically limited to three degrees of kinematic freedom, comprised of the vertical axis, commonly referred to as the Z axis, for the first degree of freedom, and the fixture element which rotates on a ball joint resulting in two additional degrees of kinematic freedom referred to as the AB axes.

The present invention has utility because of its unique combination of simplicity, flexibility, lockability, and automatability. The absence of any one of these characteristics greatly reduces the utility of the invention. Regarding simplicity, complicated systems are inherently less reliable and more costly than simple systems, and if the operating environment is wet the probability of failure is further increased. Regarding flexibility, known flexible tooling systems for contoured workpieces commonly provide three degrees of adjustability, compared to the present invention which provides six degrees of kinematic freedom.

Regarding lockability, the positions and accuracies of known systems with hundreds of workpiece support assemblies that cannot be fully immobilized are practically impossible to verify, which can result in workpieces worth hundreds of thousands of dollars being improperly machined.

Regarding automatability, an adjustable extension attachment is disclosed in <CIT> with regard to <FIG> which adds two degrees of adjustability in the XY axes. However, the limitation of this method is that the adjustment has to be performed manually. Manual adjustment has significant disadvantages in a production manufacturing environment, including the amount of time required to manually adjust each attachment, the difficulties of access that occurs when installing attachments in the middle of a large group of workpiece support assemblies, and the probability of human error occurring, including installation of attachments in incorrect locations and inaccurate adjustment of these attachments.

Referring now to the figures, and <FIG> in particular, a flexible tooling adjustment cell <NUM> is shown therein. The cell <NUM> comprises a stationary framework of columns and beams <NUM> along which robotic gantry assembly <NUM> is movably attached. The assembly <NUM> is further comprised of workpiece holding pallet <NUM> containing a plurality of movable workpiece supports <NUM>. The pallet <NUM> and workpiece supports <NUM> are supported by stationary pallet support rails <NUM>.

Storage pallets <NUM> may also be used to store the workpiece supports <NUM>. As shown, workpiece supports <NUM> are in a work position when on the holding pallet <NUM>, and in a storage position when on the storage pallet <NUM>.

One or more workpiece holding pallets <NUM> and storage pallets <NUM> may be detached from stationary pallet support rails <NUM> and moved to and from the cell by material handling vehicles and systems including Automated Guided Vehicles, wheeled transporters, and overhead cranes (not shown).

In <FIG>, the flexible tooling adjustment cell <NUM> may be configured according to operational needs. When used in conjunction with multiple support assemblies <NUM>, as best shown in <FIG>, the assemblies can support a complicated three-dimensional workpiece.

The workpiece support <NUM> may be attached to one or more fixture elements <NUM>, <NUM>, <NUM> which may be attached thereon. The attachment may be threaded. Workpiece supports <NUM> in conjunction with fixture elements <NUM>, <NUM>, <NUM> can be adjusted to a practically unlimited number of working positions, one of which is shown in <FIG>. Storage positions are shown in <FIG>. Adjustment positions are shown in <FIG>.

Fixture element <NUM> has a round sealing surface and is the preferred support for holding workpieces with gradual contours such as aircraft wing skins. Fixture element <NUM> is comprised of at least two supports <NUM> connected with crossbar <NUM> and is the preferred support for holding contoured workpieces which are predominantly cylindrical such as aircraft nacelle covers. If higher density is desired, a fixture element <NUM> with three supports <NUM> may be utilized.

Fixture element <NUM> is comprised of a contoured workpiece engaging block <NUM> which is affixed to block attachment plate <NUM> and is the preferred support for holding sharply contoured aircraft workpieces such as wing leading edges. The block <NUM> may be dedicated tooling shaped to conform specifically to a feature of the workpiece having a specific contour. The block <NUM> may be concave, convex, or a combination of concave and convex. The plate <NUM> may of a number of different sizes and shapes and adapted for attachment to a number of blocks <NUM> each having a different contour.

It should be understood that workpiece supports <NUM> can be used in combination with many of the different fixture elements <NUM>, <NUM>, <NUM>. These fixture elements <NUM>,<NUM>,<NUM> can be adjusted and immobilized with six degrees of kinematic freedom along linear axes XYZ, and around linear axes XYZ as indicated by corresponding rotary axes ABC, as best shown in <FIG>. It should be understood that rotary axis A is rotation about the X axis, rotary axis B is rotation about the Y axis, and rotary axis C is rotation about the Z axis.

Each workpiece support <NUM> comprises a support tube <NUM> and an offset arm <NUM>. The support tube <NUM> moves the offset arm (and the fixture elements <NUM>, <NUM>, <NUM>) along the z axis. The offset arm <NUM> is rotatable about an axis of the support tube <NUM> to move the fixture elements <NUM>, <NUM>, <NUM> relative to the X and Y axes.

Referring now to <FIG> showing an exploded view of <FIG> and detail views showing a plurality of workpiece support assemblies <NUM>. The robotic gantry assembly <NUM> supports a fixture building robot <NUM>. The fixture building robot comprises a number of installation elements collectively having at least the six degrees of kinematic freedom possessed by the fixture elements <NUM>, <NUM>, <NUM>. As shown, the installation elements may comprise a vertical nutrunner assembly <NUM>, a rotating housing <NUM> supporting an end effector assembly <NUM>, a gripper assembly <NUM>, and a horizontal nutrunner assembly <NUM>. Each of these subassemblies are shown in use in <FIG>. A nutrunner generally is a torque transmission device on an extendable spindle.

The fixture building robot <NUM> is controlled such that it can move workpiece supports <NUM> and corresponding fixture elements <NUM>, <NUM>, <NUM> along axes XYZ and corresponding rotary axes ABC. These assemblies perform various tasks without human intervention including detaching workpiece supports <NUM> from their storage position on storage pallet <NUM> and transporting to workpiece holding pallet <NUM>. Operations further include attaching workpiece support assemblies in storage position to workpiece holding pallet <NUM>, and adjusting and immobilizing workpiece support assemblies to the positions required to hold a large workpiece such as an aerospace wing skin <NUM> as shown in <FIG> for manufacturing operations. A plurality of workpiece supports <NUM> in working position as required to hold workpieces of varying sizes may thus be detached, transported, attached and adjusted sequentially.

The positions of fixture elements <NUM>, <NUM>, <NUM> may be individually plotted and placed in a processor, or may be determined by the processor itself to match a particular contoured workpiece. In either case, the workpiece supports <NUM> are each individually moved by the fixture building robot <NUM>. The workpiece supports <NUM> contain no internal mechanisms, motors, or electronics capable of moving on its own.

Once manufacturing operations have been completed the fixture building robot <NUM> may return workpiece support assemblies in working position back to storage position, detach them from workpiece holding pallet <NUM>, transport them back to storage pallet <NUM> and re-attach them to storage pallet <NUM>. Further details relating to the workpiece support <NUM> adjustment sequence are provided in <FIG>.

Referring now to <FIG> , a plurality of workpiece holding pallets are moved by an automated guided vehicle <NUM> between stationary pallet support rails <NUM>. Each workpiece holding pallet <NUM> supports a plurality of workpiece supports <NUM> in working position that have been previously adjusted and immobilized by the fixture building robot (<FIG>).

Once pallets <NUM> are in position, a large contoured workpiece <NUM> may be held in place for machining operations. These machining operations may include waterjet trimming and drilling. The quantity and arrangement of stationary pallet support rails <NUM> and workpiece holding pallets <NUM> can be changed for each installation to accommodate wide and long workpieces as shown which require multiple holding pallets <NUM> abutted end to end and side to side, or long narrow workpieces which require multiple holding pallets <NUM> abutted end to end. In addition, smaller workpieces which might fit upon a single holding pallet <NUM>.

With reference to <FIG>, a workpiece support <NUM> is shown in its working position and storage position. Each figure shows a fixture element <NUM>. The centerline of the fixture element <NUM> can be adjusted in the XY axis directions as shown in <FIG> by rotation of offset arm <NUM>. As shown, the offset arm <NUM> has an internally-disposed channel within which the fixture element <NUM> can traverse. As shown, the fixture element <NUM> comprises a dovetail block <NUM> (<FIG>, <FIG>) which is complementary to the channel, which is a dovetail-shaped groove.

The height and angularity of the fixture element <NUM> can be adjusted by moving it along the Z axis and rotating it around the AB axes until desired locations are obtained. Since the fixture element <NUM> is of a circular shape the adjustment of C axis rotational angularity is normally not required.

In the storage position, the centerline of the fixture element <NUM> may be adjusted in the XY axes by rotating rotation of offset arm <NUM> to, for example, the <NUM>:<NUM> position. The fixture element <NUM> may also be moved along the channel in offset arm <NUM> until the fixture element <NUM> is concentric with support tube <NUM> as shown in <FIG>.

Referring now to <FIG>, a fixture element <NUM> is shown in the working position and storage position. This embodiment incorporates two fixture elements <NUM> which are movably connected to channels shown in crossbar <NUM>. Such connection allows these fixture elements <NUM> to be adjusted independently along linear axes XY and rotary axes AB, together with crossbar <NUM> which can be adjusted independently along linear axes XYZ and rotary axes ABC.

Since two fixture elements <NUM> are mounted on crossbar <NUM> which also can be rotated around the ABC axes, dual fixture element assembly <NUM> provides an additional angular adjustment range which allows it to hold contoured workpieces which are predominantly cylindrical, such as aircraft nacelle covers, with all workpiece support assemblies mounted on the same plane.

The storage position may require the centerline of the dual fixture element assembly <NUM> to be adjusted in the XY axes as shown in <FIG> by rotating the offset arm <NUM> to, for example, the <NUM>:<NUM> position as shown in <FIG>, together with moving the dual fixture element assembly <NUM> along the channel in offset arm <NUM> until the workpiece engaging end effector assembly <NUM> is concentric with support tube <NUM>. Storage position may require that crossbar <NUM> be rotated so it is parallel to said offset arm <NUM>.

Referring now to <FIG>, the workpiece support <NUM> is shown with a contoured fixture element <NUM>. The centerline of the contoured fixture element <NUM> can be adjusted in the XY axis by rotating the offset arm <NUM> as shown in <FIG>. Further, the contoured fixture element <NUM> may be moved along the channel in offset arm <NUM> to the desired location.

Referring now to <FIG> and <FIG>, the support assembly comprises the support tube <NUM> within a pedestal <NUM>. The height of support tube <NUM> can be adjusted along the ZC axes at multiple heights and angles. Support tube <NUM> can be immobilized relative to pedestal <NUM> by tightening the support tube lock screw <NUM>. Offset arm <NUM> is attached to support tube <NUM>. The workpiece support <NUM> comprises an upper vacuum tube <NUM> and lower vacuum tube <NUM>. The upper vacuum tube <NUM> is permanently attached to offset arm <NUM> and movably connects to lower vacuum tube <NUM> which is attached to the pedestal <NUM>. The lower vacuum tube <NUM> is connected to a vacuum system within the workpiece holding pallet <NUM>. As best shown in <FIG>, a flexible vacuum tube <NUM> is attached to the support tube <NUM> and the dovetail block <NUM> such that the vacuum tubes <NUM>, <NUM> are in communication with an internal passage <NUM> within offset arm <NUM>.

The fixture element (whether type <NUM>, <NUM>, or <NUM>) is attached to the dovetail clamp block <NUM> by pivot ball <NUM>. A clamp disk <NUM> may be acted upon by the pivot ball <NUM> which further acts upon dovetail clamp block <NUM> causing it to be wedged frictionally within offset arm <NUM>. This causes immobilization of the fixture element <NUM>, <NUM> or <NUM> relative to offset arm <NUM>.

Conversely the fixture element <NUM>, <NUM> or <NUM> may be rotated to remove frictional force between dovetail clamp block <NUM> and offset arm <NUM>. As a result, the dovetail clamp block <NUM> may be mobilized relative to the dovetail groove in the top of offset arm <NUM>. The pivot ball <NUM> comprises an internal passage such that vacuum pressure from tube <NUM> is applied at a surface of the fixture element <NUM>, <NUM>, <NUM>.

Attachment screws <NUM> interact with the pedestal <NUM> to locate it on the pallets <NUM>.

<FIG>, <FIG> and <FIG> show components of fixture elements <NUM>, <NUM> and <NUM>, respectively. Each of these fixture elements can be internally mobilized, which is the state in which workpiece engaging surfaces <NUM> can be rotated freely around ABC axes relative to pivot ball <NUM>. The fixture elements <NUM>, <NUM>, <NUM> can be internally immobilized, which refers to the state in which the workpiece engaging surfaces <NUM> is fixed in position relative to the pivot ball <NUM> at the orientation provided prior to immobilization.

Referring now to <FIG>, internal immobilization of fixture elements <NUM>, <NUM>, <NUM> is achieved by tightening three adjustment clamp screws <NUM>. The screws <NUM> are attached to a clamp flange <NUM>.

Each of the fixture elements <NUM>, <NUM>, <NUM> has nine holes located in the workpiece engaging surface <NUM>. These holes each engage with an element of the end effector assembly <NUM> disposed on the fixture building robot <NUM> (<FIG>). Preferably, there are three sets of three holes, with the clamp screws <NUM> located in one such set.

With reference to <FIG>, <FIG>, <FIG>, fixture element <NUM> is shown in detail. The clamp screws <NUM> may be actuated to cause a datum reference flange <NUM> to act upon a socket flange <NUM> and further causing clamp flange <NUM> to act upon conical clamp ring <NUM>. This further causes the socket flange <NUM> and conical clamp ring <NUM> to act upon pivot ball <NUM> which frictionally immobilizes the position of socket flange <NUM> relative to the position of pivot ball <NUM>.

Internal mobilization is achieved by loosening the three adjustment clamp screws <NUM>.

Alignment dowels <NUM> allow torsional loads to be applied to datum reference flange <NUM> and socket flange <NUM> while maintaining alignment with clamp flange <NUM>. An O-ring seal <NUM> prevents leakage of vacuum between socket flange <NUM> and pivot ball <NUM>.

In <FIG>, <FIG>, a dual member fixture element <NUM> may be similarly immobilized. Internal immobilization of the crossbar <NUM> assembly is achieved by tightening three adjustment clamp screws <NUM> which are attached to clamp flange <NUM> causing datum reference flange <NUM> to act upon crossbar <NUM>. This further causes clamp flange <NUM> to act upon conical clamp ring <NUM> and further causing crossbar <NUM> and conical clamp ring <NUM> to act upon pivot ball <NUM> which frictionally immobilizes the position of crossbar <NUM> relative to the position of pivot ball <NUM>. Internal mobilization is achieved by loosening three adjustment clamp screws <NUM> which releases frictional clamping force and allows the position of crossbar <NUM> to be mobilized relative to the position of pivot ball <NUM>.

Alignment dowels <NUM> allow torsional loads to be applied to datum reference flange <NUM> and crossbar <NUM> while maintaining alignment with clamp flange <NUM>. O-ring seal <NUM> prevents leakage of vacuum between flexible vacuum tubes <NUM> connected to crossbar vacuum hole <NUM> and pivot ball <NUM>. Two fixture elements <NUM> are attached to dovetail clamp block <NUM> by pivot ball <NUM> with, for example, right-hand threads thereby allowing right-hand rotation applied to an internally immobilized fixture element <NUM> around the C axis (<FIG>) to be transferred through pivot ball <NUM>. The pivot ball <NUM> acts upon clamp disc <NUM> which causes the dovetail clamp block <NUM> to be wedged frictionally within crossbar <NUM>, immobilizing the fixture element <NUM> relative to crossbar <NUM>. Conversely the application of left-hand rotation to the fixture element <NUM> removes frictional force between dovetail clamp block <NUM> and crossbar <NUM> thereby allowing dovetail clamp block <NUM> to be mobilized relative to crossbar <NUM>.

In <FIG>, <FIG>, a contoured fixture element <NUM> is similarly constructed. Internal immobilization is achieved by tightening of three adjustment clamp screws <NUM> which are attached to clamp flange <NUM>. This causes the datum reference flange <NUM> to act upon a block attachment plate <NUM>. As a result, clamp flange <NUM> acts upon conical clamp ring <NUM> and causes the block attachment plate <NUM> and conical clamp ring <NUM> to act upon pivot ball <NUM>. This frictionally immobilizes the position of block attachment plate <NUM> relative to the position of pivot ball <NUM>. Internal mobilization is achieved by loosening three adjustment clamp screws <NUM> which releases frictional clamping force and allows the position of block attachment plate <NUM> to be mobilized relative to the position of the pivot ball <NUM>.

Alignment dowels <NUM> allow torsional loads to be applied to datum reference flange <NUM> and block attachment plate <NUM> while maintaining alignment with clamp flange <NUM>. O-ring seal <NUM> prevents leakage of vacuum between block attachment plate <NUM> and pivot ball <NUM>.

Referring now to <FIG>, the offset arm <NUM> is permanently attached to support tube <NUM>. Internally, the upper vacuum tube <NUM> is permanently attached to offset arm <NUM> and movably connects to lower vacuum tube <NUM> which is permanently attached to pedestal <NUM>. The upper vacuum tube <NUM> and lower vacuum tube <NUM> are internally sealed, and may telescope. As shown, the upper vacuum tube <NUM> surrounds a portion of the lower vacuum tube <NUM>, but other configurations are anticipated. The internal passage <NUM> is in communication with a flexible tube <NUM>. The flexible tube attaches to the dovetail clamp block <NUM> at all positions within the channel of the offset arm <NUM>.

Referring now to <FIG>, the process of orienting the fixture element <NUM> on a workpiece support <NUM> is shown. It should be understood that while a type <NUM> fixture element is shown, a type <NUM> or <NUM> support would be oriented in a similar way.

The fixture building robot <NUM> comprises an inner housing <NUM> and the outer housing <NUM>. Clamp cylinders <NUM> are attached to a flange ring <NUM>. The flange ring <NUM> is swivably supported by the inner housing <NUM>. The end effector assembly <NUM> is attached to the flange ring <NUM>.

The clamp cylinders <NUM> frictionally immobilize flange ring <NUM> relative to robotic end effector inner housing <NUM> when pressurized and allow flange ring <NUM> to be rotated within robotic end effector inner housing <NUM> when depressurized.

The robot <NUM> further comprises three attachment nutrunner motors 47A and three adjustment nutrunner motors 47B. Each attachment nutrunner motor 47A is attached to a corresponding attachment spindle 51A. Each adjustment nutrunner motor 47B is attached to a corresponding adjustment spindle 51B.

As the robotic end effector assembly <NUM> begins interfacing with fixture element <NUM>, three nutrunner alignment dowels <NUM> in the robotic end effector assembly <NUM> are inserted into corresponding alignment holes in fixture element <NUM> thereby allowing torsional forces to be transferred from the robotic end effector assembly <NUM> to the fixture element <NUM>, <NUM> or <NUM>.

The attachment nutrunner motors 47A rotate the three attachment nutrunner spindles 51A. The spindles may be attached to attachment drivers <NUM>, and distally attached screws <NUM>, all in alignment with nutrunner motors 47A. The three attachment screws <NUM> are threadedly inserted into fixture element <NUM> at attachment holes <NUM> as shown in <FIG>.

Three adjustment nutrunner motors 47B are connected with the three adjustment nutrunner spindles 51B. These are connected to adjustment drivers <NUM> in alignment with adjustment nutrunner motors 47B. The drivers <NUM>, when the end effector assembly <NUM> is attached to the fixture element <NUM>, are aligned with the three adjustment clamp screws <NUM> located on top of fixture element <NUM>. This allows clamp screws <NUM> to be tightened to immobilize the fixture element <NUM> or loosened to mobilize the fixture element <NUM>.

The gripper assembly <NUM>, as best shown in <FIG>, interfaces with transport studs <NUM> to lift and carry a workpiece support <NUM> from the storage pallet <NUM> to the workpiece pallet <NUM>. In addition, the vertical nutrunner assembly <NUM> loosens four attachment screws <NUM> disposed at the base of the pedestal <NUM>. After the screws <NUM> are loosened, the gripper <NUM> interfaces with transport studs <NUM> to lift and move the workpiece support <NUM>.

In <FIG>, a portion of the stationary framework of columns and beams <NUM> is removed for clarity. Fluidic clamp cylinders <NUM> are attached to robotic end effector inner housing <NUM> and allow flange ring <NUM> to be rotated within robotic end effector inner housing <NUM> when fluidic clamp cylinders <NUM> are depressurized and robotic end effector assembly <NUM> is attached to datum reference flange <NUM> by tightening three attachment screws <NUM> using the attachment nutrunner motors 47A and then rotating the outer housing <NUM>. Once the desired angle for robotic end effector assembly <NUM> is reached, fluidic clamp cylinders <NUM> are pressurized to immobilize robotic end effector assembly <NUM> relative to robotic end effector inner housing <NUM>.

In <FIG>, the workpiece support <NUM> is shown in transit, being held by the gripper <NUM>.

In <FIG>, the workpiece support assembly <NUM> is in the process of being attached to workpiece holding pallet <NUM>. This process includes moving robotic vertical nutrunner assembly <NUM> to a desired table location as corresponding to a plurality of threaded table holes <NUM>. The four attachment screws <NUM> are tightened by the vertical nutrunner assembly <NUM> and the gripper assembly <NUM> is detached from the workpiece support <NUM>.

In <FIG>, the robotic horizontal nutrunner <NUM> is interfacing with the workpiece support <NUM> to allow mobilization for adjustment of the end surface <NUM>. This process includes moving robotic gantry assembly <NUM> until the horizontal nutrunner <NUM> is in alignment with support tube lock screw <NUM>. The horizontal nutrunner <NUM> loosens the lockscrew <NUM>, allowing the support tube <NUM> to extend relative to the pedestal <NUM> (<FIG>).

In <FIG>, the end effector assembly <NUM> is interfacing with fixture element <NUM> as described above, to grip and mobilize the fixture element <NUM>. This process includes moving robotic end effector outer housing <NUM> until robotic end effector assembly <NUM> is coincident with fixture element <NUM>. The three attachment screws <NUM>, as shown in <FIG>, are tightened with three attachment nutrunner motors 47A acting upon three attachment nutrunner spindles 51A further acting upon three attachment drivers <NUM> as shown in <FIG>. This causes the end effector assembly <NUM> to be attached to the fixture element <NUM>, such that its position can be edited.

In <FIG>, the fixture element <NUM> has been moved to its final Z axis workpiece holding position by the end effector assembly <NUM>. This process includes loosening support tube lock screw <NUM> with the robotic horizontal nutrunner assembly <NUM>. The support tube <NUM> telescopes out of the pedestal <NUM> (<FIG>).

In <FIG>, the offset arm <NUM> has been rotated by the robotic end effector assembly <NUM>. This process includes rotation of the outer housing <NUM> which is attached to the end effector assembly <NUM>, which in turn is attached to the fixture element <NUM>. Rotation of the fixture element <NUM> causes the support tube <NUM> to rotate within the pedestal <NUM>, changing the relative angle of the offset arm <NUM>. Once the desired rotation angle has been reached, the horizontal nutrunner assembly <NUM> tightens the support tube lock screw <NUM> thereby immobilizing support tube <NUM> and thereby immobilizing offset arm <NUM> at the desired rotation angle and height.

In <FIG>, the fixture element <NUM> is being rotated by the end effector assembly <NUM> to mobilize the fixture element <NUM> and the dovetail clamp block <NUM> as shown in <FIG>. This process includes rotation of the outer housing <NUM> which is attached to robotic end effector assembly <NUM>. This rotates the fixture element <NUM> relative to the dovetail clamp block <NUM> in a loosening direction, releasing frictional clamping pressure between clamp disc <NUM> as shown in <FIG> and offset arm <NUM>. The dovetail clamp block <NUM> is thereby mobilized, allowing the block <NUM> and fixture element <NUM> to be moved slidably along dovetail groove in top of offset arm <NUM>.

In <FIG>, the fixture element <NUM> has been slidably moved along dovetail groove in top of offset arm <NUM> with the end effector assembly <NUM>. This process includes moving the end effector assembly <NUM> with the robotic gantry assembly <NUM> to its desired XY axis positions as shown in <FIG> relative to workpiece holding pallet <NUM>.

In <FIG>, the fixture element <NUM> is being rotated by the end effector assembly <NUM> to immobilize the dovetail clamp block <NUM> as shown in <FIG>. This process includes rotating the outer housing <NUM>, and end effector assembly <NUM> while attached to the fixture element <NUM> in a tightening direction. This creates frictional clamping pressure between clamp disc <NUM> as shown in <FIG> and the offset arm <NUM>.

In <FIG>, the fixture element <NUM> is being rotated by the end effector assembly <NUM> to its final working position. The rotation of the fixture element <NUM> is mobilized by threadedly loosening the three adjustment clamp screws <NUM> with the three adjustment drivers <NUM> as shown in <FIG>. The end effector assembly <NUM> is moved to the desired AB axis positions. The fixture element <NUM> is immobilized by tightening the adjustment clamp screws <NUM> with adjustment drivers <NUM> as shown in <FIG>.

The end effector assembly <NUM> is then detached from the fixture element by loosening attachment screws <NUM> with the attachment drivers <NUM> as shown in <FIG>.

In <FIG>, workpiece support <NUM> is shown in its working position having been installed on the workpiece holding pallet <NUM>. The process is then repeated until the required plurality of workpiece support assemblies have been installed on workpiece holding pallet <NUM> in required locations and adjusted to required positions to hold desired contoured workpiece.

With reference to <FIG>, a workpiece <NUM> having a deeply contoured concave region shown being engaged by a support <NUM> having a fixture element <NUM>. As shown, the fixture element <NUM> can pivot to approximately ninety degrees relative to the longitudinal axis of the workpiece support <NUM>. Likewise, in <FIG>, a convex region of a workpiece <NUM> is being engaged similarly by fixture element <NUM>.

In <FIG>, a workpiece support <NUM> having a transverse fixture element <NUM> is shown. The transverse fixture element <NUM> is similar to fixture element <NUM> (<FIG>), but is disposed in its default condition at a transverse angle to the longitudinal axis of the workpiece support <NUM>. As a result, transverse fixture element <NUM> likewise comprises adjustment clamp screws <NUM> utilized to immobilize the fixture element <NUM> relative both to the support arm <NUM> and pivot ball <NUM>. The transverse fixture element <NUM> can likewise traverse a dovetail groove.

In <FIG>, a deeply contoured fixture <NUM> is shown. This workpiece <NUM> has side walls set almost perpendicularly to the pallet <NUM>. Transverse fixture elements <NUM> are helpful in maintaining support for such a workpiece <NUM>.

With reference to <FIG>, a locating fixture <NUM> is shown. The locating fixture <NUM> is similar to fixture <NUM>, but utilizes a locating pin <NUM>. The locating pin <NUM> may be placed through a corresponding hole in a workpiece <NUM>. As shown in <FIG> and <FIG>, the locating fixture is engaging the workpiece <NUM> to establish its position. As with other fixtures <NUM>, <NUM>, <NUM>, <NUM>, the locating fixture <NUM> may be manipulated about five or six degrees of freedom by translation in a dovetail groove, manipulation of the support tube <NUM> relative to the pedestal, etc..

It may be advantageous, after locating the workpiece <NUM> and ensuring it is well-supported on the plurality of fixtures <NUM>, <NUM>, <NUM>, <NUM> to remove the locating fixtures <NUM> and pins <NUM> prior to beginning machining operations.

<FIG> and <FIG> show a plurality of fixtures <NUM>, <NUM>, <NUM>, <NUM> in use on workpiece supports <NUM> on a deeply contoured, complex workpiece <NUM>. <FIG> shows the assembly in perspective, while <FIG> is a top view, with the workpiece <NUM> made transparent so that different fixtures <NUM>, <NUM>, <NUM>, <NUM> may be shown engaging the bottom surface of the workpiece. The pallet <NUM> is omitted from the view of <FIG> for clarity.

Claim 1:
A workpiece support assembly (<NUM>) comprising:
- a pedestal (<NUM>);
- a support tube (<NUM>) carried by the pedestal (<NUM>) and having a longitudinal axis;
- an offset arm (<NUM>) carried by the support tube (<NUM>) and selectively rotatable about its longitudinal axis, the arm having a rectilinear channel formed therein; and
- a fixture element (<NUM>) supported above the channel and movable along a line parallel thereto, the fixture element (<NUM>) having at least two degrees of rotational freedom.