Method and apparatus for processing workpieces and assembling and disassembling of structural units

A method and an apparatus for performing mechanical operations on a workpiece secured on a first member for movement relative to a second member in at least one of three orthogonal directions at a precision in the .mu.m range. Selectively energizable magnets are provided between the first and second members cause the first member to assume a floating state relative to the second member and to provide such movement. The second member is provided with a chamber for receiving the first member and is with openings for the controlled flow of pressurized fluid to augment the action of the magnets.

BACKGROUND OF THE INVENTION.
 1. Field of the Invention.
 The invention, in general, relates to a method and an apparatus for
 mechanically processing of workpieces and for assembling and disassembling
 of structural units and, more particularly, to an apparatus in which
 workpieces to be processed, or structural units to be assembled or
 disassembled, as the case may be, are secured on an adjustable and,
 optionally, removable clamping tray of the kind integrated in such machine
 tools as, for instance, CNC-controlled grinding machines, milling
 machines, boring mills and the like, or utilized in transfer lines for
 assembling or disassembling structural units.
 2. The State of the Art.
 To reduce idle times during mechanical processing, assembly or disassembly
 operations, and to increase productivity and manufacturing capabilities,
 it is common practice to incorporate individual machine tools or even
 entire machine systems into assembly or disassembly lines. Proposals aimed
 at satisfying these requirements have not been lacking. They have been
 addressed to such operations as securing and releasing workpieces on
 workpiece clamping trays, aligning workpieces relative to processing
 tools, positioning workpieces for purposes of processing, as well as to
 motors accommodating such operations.
 For instance, German patent DE 21 02 234 A1 relates to a drive for moving,
 within an assembly line, tool supports into predetermined positions in a
 transport path. To this end, a plurality of primary and secondary
 components of conventional linear motors is used cooperating alternatingly
 and by pulsed energization. The primary components are disposed in spaced
 relationship along a transport path, either singly or in groups. The
 secondary components are mounted on the tool support.
 Grouped primary components are aligned either in parallel or angularly with
 respect to each other, and predetermined primary groups are connected in a
 consecutive sequence to a source of three-phase or direct current by means
 of switches actuated by the tool support. Each the secondary components
 consists of a plate of high magnetic conductivity and, when facing a
 primary component, and which is covered by an electrically highly
 conductive plate. Both secondary components are longer than any one of
 those primary components which are disposed in the same manner as they
 are.
 Two parallel strips of high magnetic conductivity are embedded in the plate
 of high electric conductivity and extend laterally thereof. Each one of
 the strips is wider than the width of notches of the primary components
 and the center spacing between them which corresponds to the spacing
 between two opposite poles of the primary components.
 In such an arrangement an air cushion is built up between the tool support
 and the transport path, and a conventional linear motor is utilized as a
 drive.
 Clamping or lifting of workpieces by means of a magnetic clamping tray is
 known from European patent EP 0,357,904 A1 which describes a magnetic
 clamping tray capable of securely retaining not only workpieces made from
 different materials, but also workpieces made from weakly and non-magnetic
 materials. Its surface is structured such that it supports a workpiece in
 any position; at the same time it ensures appropriate vacuum pressure by
 an unimpeded air flow.
 Two embodiments are described. In one embodiment slots or bores are formed
 in the magnetic pole sections between pole conduits which are made of
 non-ferromagnetic material and which are filled with a fine porous
 sintered metal.
 In the other embodiment, the slots are provided in the pole conduits and
 are also filled with a fine porous sintered metal which in this case,
 however, is not ferromagnetic.
 While it is possible magnetically to secure a workpiece with the described
 combination vacuum and magnetic clamping tray, it is not possible, for
 instance, to align or move a workpiece provided on the magnetic clamping
 tray.
 Furthermore, German patent DE 196 28 921 A1 discloses a machine tool system
 for mechanical operation which consists of a machine base in operative
 connection with a gantry supported laterally of the foundation of the
 machine and extending over the machine base. The base of the machine is
 provided with a bed for receiving and supporting a clamping device. The
 receiving bed may be moved in the direction of the longitudinal or x-axis
 of the machine.
 The receiving bed is provided with a clamping device which may be
 magnetically supported, arrested and positioned and which workpieces to be
 secured on the clamping tray. The entire clamping device may be
 magnetically lifted, moved and positioned. It may also be lowered and
 magnetically clamped, preferably by hybrid magnets, on the receiving bed.
 It is also known to structure the clamping tray of such a clamping device
 for movement and adjustment not only along its x and y axes, but also for
 angular movements and adjustments about its vertical axis, by appropriate
 lifting and adjustment devices.
 In these known arrangements,lifting magnets move the clamping devices with
 workpieces placed thereon are put into a floating state which state they
 may be adjusted, positioned and lowered to be secured by arresting
 magnets. With the clamping tray in this lowered and secured position, the
 workpieces may be subjected to defined processing operations.
 It is an object of the invention to provide a method and an apparatus
 capable of performing mechanical processes and operations on workpieces
 and of assembling or disassembling, as the case may be, structural units,
 and of positioning workpieces or structural units placed on a clamping
 tray of a machine system relative to tool systems, assembly devices,
 processing systems and the like which are disposed on one or more gantries
 which extend over, or are arranged around, the clamping tray.
 SUMMARY OF THE INVENTION.
 In a currently preferred embodiment there is provided a method of
 performing mechanical operations on workpieces and of handling structural
 units to be assembled or disassembled in which the workpieces or
 structural units are secured on fixed or removable workpiece clamping
 trays which as part of a clamping device or turntable may be supported in
 a floating state, adjusted and positioned by magnetic forces and/or
 pneumatic and/or hydraulic media. The workpieces secured on the clamping
 tray may be subjected to rotational processing in the floating as well as
 in the lowered position of the clamping device or of the rotor of the
 turntable. A sensor system is provided for ensuring no contact between the
 support elements of the clamping tray and a magnetic support ring or
 between the support elements of the rotor with its clamping tray and the
 housing of the turntable. Positioning of the workpieces or structural
 units relative to tool, assembly or disassembly systems at a precision in
 the pm range is ensured by a measuring and closed-loop control system.
 Direct angular positioning and measurement of rotational velocity and
 indirect measurement of the acceleration of the rotor are provided by an
 angle measuring device.
 The apparatus in one embodiment of the invention is structured as a
 clamping unit consisting of a base plate with an associated support ring
 provided with a device for adjusting the angle of inclination which in
 turn is connected to a centering plate and a workpiece clamping tray by
 means of adjustment spindles. The base plate which may be a solid plate or
 a ring is disposed within a magnetic support ring provided with an
 apertured medium chamber and a nozzle system consisting of individual
 nozzles arranged around the periphery of the magnetic support ring.
 In another embodiment of the invention there is provided a turntable
 consisting of a housing, a magnetically supported rotor including a fixed
 or removable clamping tray, lifting magnets, arresting magnets, centering
 magnets, a linear motor as well as an angle measuring device and a sensor
 system.
 Advantageously, the method in accordance with the invention provides for
 mechanically processing, treating, coating, assembling or disassembling
 and the like of workpieces or structural units arranged upon a clamping
 tray mounted on a turntable or on a clamping device, the positioning and
 adjustment of which relative to tool, processing, assembling and
 disassembling systems are carried out in a floating state of the turntable
 support and associated turntable and/or of the rotor of the turntable as
 well as the entire clamping device, whereby magnets and/or a pressurized
 pneumatic or hydraulic medium cushion is provided for generating or
 supporting the floating state of the turntable rotor within the housing of
 the turntable or of the turntable support with the turntable or clamping
 device disposed thereon.
 The mechanical processes, treatments, coatings, assembling or disassembling
 and the like of the workpieces and/or structural units may be performed in
 or by concentric, eccentric or curved path arrangements. In a concentric
 arrangement, the fixed or optionally removable clamping tray rotates about
 its vertical and magnetically supported axis of rotation, the clamping
 tray being connected to the rotor of a turntable. The rotor is
 magnetically supported within the housing of the turntable. The turntable
 support, in turn, is magnetically supported in a mechanical guide
 structure.
 Rotation and angular positioning of the rotor maybe accomplished
 mechanically or by synchronous or asynchronous linear motors. The rotation
 may be imparted by forces acting on a flange surface from below or above a
 horizontal plane, or on an offset surface of the rotor, as well as on a
 vertical plane, for instance, on the outer cylindrical surface or internal
 bore of the rotor or on the outer periphery of the rotor flange.
 In a concentric movement, vertical and horizontal magnetic adjustments of
 the clamping tray are undertaken solely to adjust the floating, i.e. the
 rotational movement of the rotor within the turntable at a precision in
 the .mu.m range and to maintain the horizontal as well as vertical magnet
 gaps, so that any engagement of the rotor with the inner wall of the
 turntable housing is prevented even under static and dynamic tilting
 moments, operational forces and the like.
 During concentric movements of the clamping tray the floating state of the
 rotor in the turntable housing may be augmented by an arrangement of
 magnets of identical polarity between the lower surface of the rotor and
 the opposite base surface of the turntable housing.
 By the concentric self-propelled movement of the clamping tray the
 workpieces secured thereon may be positioned with great precision relative
 to any machine tool systems which are movable in the direction of their x
 axis, i.e. their longitudinal axis, and which are mounted on gantries or
 near the machine, by rotational movement of the clamping tray in angles
 .phi. relative to the vertical z axis as well as to the y axis and the x
 axis of the turntable support, so that tool systems which may or may not
 be provided with their own drives can operate upon the workpieces.
 As has been mentioned supra, the clamping tray which may either be fixed or
 removable may be part of a clamping device or of a turntable. In such an
 arrangement, too, the workpieces positioned on the clamping tray may
 either be fixed by the clamping device or by the turntable rotor, or moved
 around the rotational axis of the clamping device or of the turntable
 rotor. The clamping device or the turntable rotor including clamping tray
 may be moved in a conventional or magnetically supported manner toward
 static tool systems for attaining any required position in a highly exact
 manner by rotational movement and movement along the x axis. Thereafter,
 the static or movable tool system provided with its own rotational and/or
 vertical drives, may act upon workpieces on the clamping tray, while the
 workpieces are moved along the x, y-.phi. axis of the clamping device or
 the .phi.-y axis of the turntable rotor and the x axis of the turntable
 support. A combination of the x/y-.phi. axial movement of the tool systems
 with the x-y-.phi. rotational movements of the clamping device or of the
 turntable rotor in connection with the turntable support is possible as an
 additional movement along the z axis of the tool systems and the
 omni-angular vertical movement of the described apparatus.
 Another alternative use of the described apparatus relates to mechanical
 processing of workpieces in a machine tool by the omni-angular vertical
 movement of a receiving plate of a machine tool which is moveable along
 its x axis and upon which workpieces are secured, in combination with the
 use of the described clamping device or turntable as a tool system support
 at a gantry of the machine tool, in which several tool systems are moved
 concentrically or along curves, as has been mentioned supra, and are
 acting upon the workpieces on the clamping tray.
 In eccentric movements along the workpieces, adjustment and positioning of
 the clamping device or of the turntable and clamping tray are carried out
 along the x axis of the system. This leads to curved paths which result
 from a combination of rotational and planar displacements and are provided
 by means of magnetic lifting, driving and arresting forces as well as by
 additional pneumatic and/or hydraulic media. In this connection, it is
 possible following each positioning of the workpieces/structural units
 with respect to the mentioned systems and apparatus to clamp the base
 plate of the clamping device against the magnetic support ring which
 embraces the clamping device, or the turntable rotor against the base
 plate of the housing of the turntable, and thus to secure the clamping
 tray against movements which may result from the operation and to push
 back any additional medium. It is also possible during processing,
 assembly or the like to move the clamping tray in horizontally and
 vertically curved paths in the magnetic gap between the base plate of the
 clamping device and the internal bottom surface of the magnetic support
 ring, or between the turntable rotor and the base plate of the housing of
 the turntable, with a supportive pneumatic and/or hydraulic medium
 reinforcing the magnetic gap, without any need in the interim for clamping
 the base plate against the magnetic support ring. To this end, all
 movements of the clamping device and of the clamping tray are controlled
 by an integrated CNC system.
 The necessity of the base plate which is part of the clamping device not
 physically engaging the magnetic support ring when the clamping device is
 in its elevated state, or the turntable rotor in the housing of the
 turntable not contacting the turntable support, is monitored and ensured
 by a sensor system. A measuring system ensures that adjustments of the
 clamping tray, of the clamping device as well as of the turntable, are
 performed with a precision in the .mu.m range.
 To this end, the method has been conceptualized such the requisite method
 steps may be performed singly or in combination with each other.
 Accordingly, the vertical positions of the base plate of the clamping
 device or of the rotor of the turntable may be set by magnetic forces, by
 added media, preferably air, or by a combination of magnetic forces and/or
 fluid media. Furthermore, it is possible to process, treat, assemble or
 disassemble the workpieces or structural units while the clamping device
 or the turntable is in a floating state for omni-directional positioning
 or movement as well as when it is in its lowered position, i.e. when it
 engages the magnetic support ring or the base plate of the turntable
 housing, or when the turntable support is connected to its mechanical
 guide system.
 Moreover, for purposes of assembly or disassembly, the clamping device or
 the turntable support including the turntable may be part of a given
 machine system, and may thus be arranged, for instance, in a foundation
 pit or in a transfer path.
 Machine gantries equipped with tools, processing, assembly or disassembly
 systems may move along the x axis across the entire clamping device or
 turntable support including the turntable and, hence, across the
 workpieces or structural units secured on the clamping tray.
 The clamping device which may be magnetically supported, secured and
 positioned, or the rotor of the turntable, including any workpieces or
 structural units placed on the clamping tray, is elevated, moved,
 positioned and lowered by magnetic forces and/or pneumatic and/or
 hydraulic media. The clamping device or the rotor of the turntable is
 magnetically arrested or secured, preferably by hybrid magnets. The
 clamping device is mounted in a magnetic support ring embracing the base
 plate of the clamping device, or the rotor of the turntable is mounted in
 the housing of the turntable. Lifting, arresting and drive or propulsion
 magnets are provided in the magnetic support ring; centering magnets are
 additionally provided in the turntable housing. The drive magnets
 preferably constituted as linear motors ensure that the workpieces or
 structural units placed on the clamping tray are moved and positioned
 relative to tools, processing, assembly or disassembly systems and the
 like when the clamping device or the turntable or its support are in their
 floating state.
 The play or tolerance between the magnetic support ring and the base plate
 of the clamping unit, as well as the free space between the magnetic
 support ring and the support ring of the clamping device are selected such
 that the entire clamping device may be moved or positioned rotationally or
 in a plane, i.e. about its z axis and in the direction of the x and y
 axes, depending upon the required position of the workpieces relative to
 the tools and processing system, or upon the requisite positions of the
 structural units relative to the assembly or disassembly systems.
 In the concentric arrangement of turntable and turntable support the
 rotational .phi. angle position relative to the z axis and, hence, the
 relative y axis is set by the turntable rotor. Positioning along the x
 axis is carried out by the turntable support.
 Thus, the apparatus in accordance with the invention consists of a clamping
 device provided with a base plate, a support ring, a clamping tray as well
 as a magnetic support ring which embraces the base plate of the clamping
 device. The magnetic support ring is operatively connected to the clamping
 device and is equipped with lifting, arresting and drive magnets.
 In a concentric arrangement of a turntable housing and a rotor, a clamping
 tray with a turntable support operatively connected with the turntable,
 the turntable support is movable along its x axis and is equipped with
 lifting, arresting and guide magnets. The turntable is also provided with
 lifting, arresting and drive magnets as well as additional centering
 magnets so that, with the turntable rotor and the turntable support, it
 may perform the rotational .phi. angle movement about the z axis or the
 movement relative to the y axis while always precisely maintaining the
 vertical and horizontal system axis of the entire arrangement.
 In addition, nozzle openings are provided for feeding and removing
 pneumatic and/or hydraulic media, for lifting the entire clamping system
 or turntable rotor or to aid in their floating state. Where the clamping
 device or the turntable rotor is magnetically clamped against its magnetic
 support ring or base plate of the turntable housing, respectively, the
 corresponding medium is pushed back to the internal base surface of the
 magnetic support ring by the weight of the clamping device and the
 magnetic clamping forces.
 Movement and positioning take place when the clamping device or the
 turntable rotor is in its lifted or floating state; for the lifting
 magnets and/or the medium (gas, liquid, and the like) raise the clamping
 device or the turntable rotor off the base surface of the magnetic support
 ring or the base plate of the turntable housing such that defined gaps are
 formed between the lower surface of the base plate and the inner bottom
 plate of the magnetic support ring or between the lower surface of the
 turntable rotor and the base plate of the turntable housing as well as
 between the upper surface of the base plate and the internal upper surface
 of the magnetic support ring or the upper surface of the turntable rotor
 and the turntable housing lid, so that the necessary movement and
 positioning steps of the clamping tray may be performed without the base
 plate or the turntable rotor contacting anything. The base plate of the
 clamping device may be structured either as a solid plate or as a ring.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS.
 As well as individual pieces the term "workpiece" as used herein is
 intended to connote structural units consisting of a plurality of
 individual pieces. The term "mechanically processing" and any derivatives
 thereof is intended to mean any mechanical operation which may be
 performed on a workpiece, including, but not limited to, assembly and
 disassembly operations, and which requires a precise alignment of the
 workpiece relative to a tool.
 FIG. 1 depicts a turntable 33 including a clamping tray 2 and a turntable
 support 47 integrated and arranged in a complete machine tool system.
 Integration and arrangement of a clamping device 1 and associated clamping
 tray 2 are shown in FIG. 2. The figures also indicate the directions 24,
 25, 26, 28 in which the clamping tray 2, whether it be part of a turntable
 33 and turntable support 47 or of a clamping device 1, may be moved. The
 clamping tray 2 will be understood by persons skilled in the art to
 constitute a support configured for securely holding a workpiece in a
 predetermined position. They also show the gantry 10 of the machine
 extending over the clamping device 1 or over the turn table 33. The gantry
 10 supports a plurality of tools schematically depicted as being mounted
 in brackets 29. The tools are positioned to perform unspecified operations
 on workpieces (not shown) secured on the clamping tray 2.
 FIG. 3 depicts the structure and configuration of a turntable 33 in
 accordance with the invention. The turntable 33 is configured as a compact
 unit consisting of a housing 37 within which there is provided a rotor 34.
 The clamping tray 2 may either be affixed on the rotor 34 or it may be
 removably placed thereon.
 In addition, the turntable 33 is provided with lifting magnets 35 and
 arresting magnet 38. The lifting magnets 35 are disposed above the rotor
 34 and are affixed to a lid of the housing 37. The arresting magnets 38
 are arranged below the rotor 34 on a bottom plate of the housing 37.
 In addition, the turntable 33 is provided with centering magnets 36 and
 with a rotationally acting linear motor 40 which are disposed around the
 periphery of the rotor 34 in an internal wall of the housing 37. In the
 vicinity of the lifting magnets 35, the arresting magnets 38 and the
 centering magnets 36, the rotor 34 is preferably provided with sheet-metal
 zones 41 for increasing its magnetic efficiency. It will, however, be
 appreciated by those skilled in the art that the magnets 35, 36, 38 may
 act directly on the rotor 34. Whether the rotor 34 is provided with
 sheet-metal zones or not depends upon the magnetic properties of the rotor
 34.
 Air gaps 45, 44 and 43 are provided in the zones in which the lifting
 magnets 35, the arresting magnets 38 and the centering magnets 36 act on
 the rotor 34. These gaps also constitute magnetic gaps which are needed
 for positioning and rotating the rotor 34 and for its horizontal and
 vertical adjustment. Furthermore, an air gap 42 is provided between the
 linear motor 40 and the rotor 34, the rotor 34 being provided with
 permanent magnets (not shown) in the effective zone of the linear motor 40
 to act as the secondary components thereof.
 The turntable 33 is also provided with a device 39 for measuring the
 rotational angle. The device 39 is operatively connected to the rotor 34
 and is structured to provide for an exact angular positioning and
 measurement of the angle .phi. of rotation of the clamping tray 2. The
 device 39 may also be used for direct measurements of the rotational
 velocity of the clamping tray 2 and for indirect measurements of its
 acceleration.
 The action of at least some of the magnets referred to supra may be
 augmented by gaseous or liquid media. To this end, the housing 37 is
 provided with openings in which nozzles 12 are seated which serve to admit
 and to remove such media.
 The turntable 33 is also provided with sensors 46 which are positioned
 close to the centering magnets 36 and the arresting magnets 38 and which
 serve to measure the air gaps 43 and 44.
 Furthermore, the turntable 33 is provided with a catch (not shown) for
 preventing the rotor 34 in case of a malfunction, such as, for instance, a
 current failure) from touching any one of the arresting magnets 38,
 centering magnets 36 or linear motor 40 and for preventing damage to the
 turntable 33.
 The structure of a clamping device 1 and its support in a magnetic support
 ring 8 as well as their placement within a pit of a foundation have been
 depicted in FIG. 4. The clamping device 1 consists of a base plate 7 which
 but for an axial opening is structured as a solid plate. As shown in FIG.
 5, the base plate may optionally be structured as a ring 7'. A support
 ring 6 is affixed to the base plate 7 and an angular inclination device 15
 is mounted in the support ring 6. The angular inclination device 15 is
 provided with a plurality (two shown) of level setting spindles 5. A ball
 at the end of a spindle 4 is seated in a concave recess of a centering
 plate 3 and serves as a fulcrum for the clamping tray 2 affixed to, or
 optionally releasably mounted on, the centering plate 3. By lengthening
 and shortening the spindles 5 relative to the ball and socket, the angular
 inclination of the clamping tray 2 may be set. Releasable mounting of the
 clamping tray 2 on the centering plate 3 offers the advantage that the
 tray, and any workpieces placed thereon, may be moved to other processing
 machinery, unloading or storage facilities, as the case may be.
 The clamping device 1 is supported by the base plate 7 which is mounted
 within a chamber 31 of a magnetic support ring or cage 8 such that is may
 be lifted, adjusted or lowered therein without any impediment. To this
 end, the chamber 31 is dimensioned appropriately.
 The magnetic support ring 8 is provided with a bottom surface 18. Arresting
 magnets 23 and drive magnets 9 are seated within the surface 18; and in
 the upper internal surface 17 of the ring 8 there are provided lifting
 magnets 27 as well as drive magnets 9. Preferably, the support and the
 lifting magnets 23, 27 are hybrid magnets, i.e., they are made from a
 combination of electromagnets and permanent magnets.
 The drive magnets 9 preferably are structured as linear motors by means of
 which the base plate 7 may be rotated and moved along a plane. A sensor
 system (not shown) is provided to ensure that the base plate 7 stays out
 of physical contact with the magnetic support ring 8, by maintaining gaps
 16, and 32 between the inner upper surface 17 of the ring 8 and the upper
 surface 19 of the base plate 7 as well as between the lower surface 20 of
 the base plate 7 and the bottom surface 18 of the ring 8.
 When the base plate 7 is in its elevate or floating state, the entire
 clamping device 1 can be adjusted and positioned with an integrated
 measuring system ensuring that the clamping tray 2 and any workpieces or
 structural units placed thereon, are positioned with a precision in the um
 range relative to tools which may be mounted in brackets 29 as shown in
 FIG. 2.
 The arrangement of the base plate 7, 7' as shown in FIGS. 4 and 5 within
 the magnetic support ring 8 displays the floating state of the entire
 clamping device 1 as well as the arrangement and cooperation of individual
 components. In praxi, i.e. during an operation, the entire clamping device
 1, by way of its base plate 7, 7', will either rest on the bottom surface
 18 of the magnetic support ring 8 or float between the upper surface 17
 and the bottom surface 18 of the magnetic support ring 8. This state is
 achieved by moving the base plate 7, 7' into this position, either by way
 of the lifting magnets 27 and/or by the introduction of a medium (gas,
 liquid, etc.) between the lower surface 20 of the base plate 7 and the
 bottom surface 18 of the magnetic support ring 8.
 The floating state may be attained not only by the force of the magnets or
 by introducing of one of these media, but also by a combination of these
 two support systems. The lifting and arresting magnets 27, 23 augmented by
 the media admitted under pressure through nozzles 12 provided with
 connectors 14 from the exterior into the gap 16 between the lower surface
 20 of the base plate 7 and the bottom surface 18 of the magnetic support
 ring 8 cause the base plate 7, 7' to rise and dampen its vertical
 movement.
 The weight of the entire clamping device 1 including any workpieces or
 structural units on the clamping tray 2, the vertical components of
 operating forces as well as the vertical components of tilting moments
 resulting from horizontal adjustments of the base plate 7, 7' are absorbed
 by the lifting magnets 27 and/or by the cushion of any medium within the
 gap 16.
 Gaskets 13, preferably of the pre-stressed kind, are provided to seal the
 gap 16 so that the medium may become immediately effective within the gap
 16 without escaping from the outer periphery of the base plate 7, 7'.
 Controlled input and outflow of the medium (gas, liquid, etc.) into the
 gaps 16 or 32 between the base plate 7, 7' and the magnetic support ring 8
 may also take place into the free space or chamber 31 through nozzles 11
 placed around the periphery of the magnetic support ring which results in
 substantially equal pressures in the gaps 16 and 32. A gasket 30 will
 prevent the escape of medium through the gap 32.
 In this alternative structure of the input and outflow of the medium (gas,
 liquid, etc.) the weight of the entire clamping device 1 in its floating
 state, including workpieces or structural units on the clamping tray 2,
 any vertical components of operational forces as well as vertical
 components of tilting moments resulting from horizontal movement of the
 base plate 7, 7' is absorbed by the lifting magnets 27 and/or any medium
 in the gaps 16 and 32.
 There are, accordingly, sufficient degrees of freedom for the base plate 7,
 7' within the magnetic retention ring 8 to ensure that the entire clamping
 device 1 may be moved and positioned in accordance with technological
 requirements.
 In the embodiment of the clamping device 1 depicted in FIG. 5, the base
 plate 7' is structured as a ring. It also shows disposition within the
 magnetic support ring 8 and the relationship between the base plate 7' and
 the clamping tray 2. The base plate 7' is supported in the magnetic
 support ring 8 in substantially the same manner as has previously been
 described in connection with base plate 7. It is to be noted that the
 level clamping tray 2 may be vertically adjusted relative to the base
 plate 7' by the ball spindle 4. The structure of the angular adjustment
 device 15 is substantially as has been described supra connecting the
 clamping tray 2 with the base plate 7', so that the rotational and planar
 adjustments previously described may be made by the base plate 7'
 independently of the angular adjustment device 15. The direct rigid
 connection of the angular adjustment device 15 in the clamping device 1
 does not affect its function since its components are still capable of
 adjusting and arresting the clamping tray 2 in any desired vertical
 position. The structure of the base plate 7' has been selected so that, as
 shown in FIG. 6, as a support for movable tool systems 21 it can be
 adjusted in the direction of the y axis 24, the x axis 25, rotationally
 symmetric in direction 26 as well as, to the extent of the height of the
 gap, in the direction of the z axis 28.
 A preferred structure and arrangement of the drive magnets 9 and of the
 arresting magnets 23 in the bottom surface of the magnetic support ring 8
 is shown in the sectional view of FIG. 7. Those skilled in the art will
 know, however, that other arrangements are feasible as well.
 As regards the functional cycle it is to be mentioned that owing to the
 extensive variability of the system, workpieces to be processed and/or
 structural units to be assembled or disassembled placed on the clamping
 tray 2 may be vertically adjusted at a precision in the pm range relative
 to tools, processing, assembly or disassembly systems mounted either on
 the machine portal 10 or stationarily and concentrically around the
 clamping tray 2. Depending upon technological dictates the adjustment may
 be repeated as often as necessary for each workpiece relative to each tool
 system. This applies also to positioning and adjusting of tool,
 processing, assembly and disassembly systems 21 mounted on the base plate
 7' as regards their rotational and planar adjustment relative to
 workpieces and/or structural units placed on the clamping tray 2.
 While a workpiece is being worked upon the base plate 7' is in its lowered
 position, i.e., it rests upon the inner bottom surface 18 of the magnetic
 support ring 8 against which it is secured by means of the energized
 arresting magnets 23 in order to prevent movement of the workpieces during
 the operation. Alternatively, it may be in a floating state as a result of
 the energized lifting magnets 27 and/or any medium (gas, liquid, etc.)
 pumped into the gaps 16, 32 through appropriate nozzles 11, 12 to be moved
 at a precision in the .mu.m range by the drive magnets 9 acting upon the
 base plate 7' along a curve generated by a combination of rotational and
 planar movements in accordance with the technological requirements for the
 processing of the workpieces.
 Vertical movements of the base plate 7' which may result from gravitation,
 tilting moments and operating forces are controlled by the lifting magnets
 27 and/or absorbed by the pressurized medium. Defined spaces between the
 base plate 7' and the upper surface 17 as well as the bottom surface 18 of
 the magnetic support ring 8 are controlled and adjusted by a sensorized
 control system in a manner which prevents any contact between the base
 plate 7' and the magnetic support ring 8. The medium is controlled
 correspondingly, for instance by being fed into or removed from the gaps
 16, 32.
 Rotational and/or planar movement of the base plate 7' in its floating
 condition is provided by the lifting magnets 27 and by the drive magnets
 9. The latter are preferably structured as linear motors. Movement may
 take place from one position on the clamping tray 2 to a next one followed
 by a controlled setting down of the base plate 7' and its arresting by the
 arresting magnets 23 while maintaining the new position in the magnetic
 support ring 8. However, it is also possible to process the workpieces
 while the base plate 7' is moving in the gap between the lower surface 20
 of the base plate 7' and the bottom surface 18 of the magnetic support
 ring 8 along a curve. The precision of the curve is within the .mu.m
 range.
 The individual magnets may be controlled in such a manner that the lifting
 magnets 27, for instance, on the basis of ferromagnetic forces of
 attraction form and maintain an air gap 32 between the upper surface 17 of
 the magnetic support ring 8 and the upper surface 19 of the base plate 7'.
 The gap 16 between the lower surface 20 of the base plate 7' and the
 bottom surface 18 of the magnetic support ring 8 may be similarly formed
 and maintained. The selected arrangements and structures of the magnets
 ensure that the magnetic forces of the arresting magnets 23 and of the
 lifting magnets 27 during their actuation is provided at their operational
 points substantially without power. Thus the floating clamping device 1 or
 the base plate 7' may be moved rotationally and in a plane, as well as
 positioned, without additional moving elements such as toothed rack,
 spindles and the like, with or without additional media such as a gas or a
 liquid or the like.
 FIG. 8 schematically shows a combination of the turntable 33 of FIG. 3 and
 a turntable support 47 within a mechanical guide structure 50. As may be
 seen, the turntable support 47, in a manner similar to the rotor 34 (FIG.
 3), is maintained in a defined manner within the structure 50, and is
 surrounded by magnetic gaps, by support, arresting and centering magnets
 51, 52, 53, and it may be moved by drive magnets 54 in the x direction 25
 (FIG. 1). It is possible to lower the turntable support 47 in the guide
 structure 50 by means of the arresting magnets 52 and securely to arrest
 it by a magnetic force.
 Gaseous or liquid media may be introduced through conduits 55, 56 to raise
 the turntable support 47 including the turntable 33 within the structure
 50 and to establish a gas and/or liquid cushion between the turntable
 support 47 and the guide structure 50.
 Gaskets 57 are provided substantially to prevent an escape of the gas
 and/or the liquid from the mechanical guide structure 50.
 The position of the turntable support 47 in the mechanical guide structure
 50 is determined by sensors 58 and is moved under closed-loop control with
 the turntable 33 (FIG. 1).
 The essential advantages of the invention reside in the arrangement of a
 plurality of tool, processing, assembly and/or disassembly systems etc. at
 a machine portal and/or concentrically around the entire apparatus for
 mechanically processing workpieces and/or for assembling or disassembling
 structural units. In particular, a multiple processing center may be
 created, expanded by combining processing and assembly operations, while
 saving a number of individual machines or assembly stations. For instance,
 the turntable on the turntable support may be moved touchlessly,
 noiselessly and without requiring lubrication, with workpieces secured on
 its clamping tray, along a transfer path or assembly line. Highly precise
 movements in the x, y, z and (p directions are accomplished by this
 combination, and peripheral machinery and/or assembly units need execute
 complementary movement only.
 Other advantages are achieved by mounting the workpieces and structural
 units on supports which may be selectively subjected either to a floating
 state without physical contact with other machine structures or to a
 securely clamped arrangement. The apparatus in accordance with the
 invention, because of its versatility, obviates the need for additional
 processing and treatment machines as well as transfer mechanisms.
 The touchless movements provided for by the apparatus in accordance with
 the invention result in substantially no wear and tear and obviate the
 need for lubricants and lubrication stations. This, in turn, leads to an
 extended service life of the machine, reduced maintenance and costs.
 Further advantages are derived from the fact that the apparatus in
 accordance with the invention requires no refitting and since positioning
 and placing of workpieces can be accomplished more quickly, idle times of
 the apparatus are significantly reduced.
 An annularly structured base plate 7' may be utilized as a tool support
 system or as a robot support system for assembly or disassembly operations
 and may be moved around the clamping tray 2 to provide for processing of
 workpieces or for assembly or disassembly operations in a flexible and
 efficient manner. In such an arrangement, the base plate 7' will be moved
 as described supra.
 The manner in which tool or assembly or disassembly systems 21 are mounted
 on the base plate 7' and the arrangement or disposition of fixed tool or
 assembly or disassembly systems 22 on the magnetic support ring 8 is also
 depicted in FIG. 6.