Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q1/00—Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members
  • B23Q1/25—Movable or adjustable work or tool supports
  • B23Q1/26—Movable or adjustable work or tool supports characterised by constructional features relating to the co-operation of relatively movable members; Means for preventing relative movement of such members
  • B23Q1/38—Movable or adjustable work or tool supports characterised by constructional features relating to the co-operation of relatively movable members; Means for preventing relative movement of such members using fluid bearings or fluid cushion supports
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C29/00—Bearings for parts moving only linearly
  • F16C29/02—Sliding-contact bearings
  • F16C29/025—Hydrostatic or aerostatic
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
  • G01B5/0002—Arrangements for supporting, fixing or guiding the measuring instrument or the object to be measured
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
  • G01B5/004—Measuring arrangements characterised by the use of mechanical techniques for measuring coordinates of points
  • G01B5/008—Measuring arrangements characterised by the use of mechanical techniques for measuring coordinates of points using coordinate measuring machines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C2322/00—Apparatus used in shaping articles
  • F16C2322/39—General buildup of machine tools, e.g. spindles, slides, actuators

Definitions

• the present invention relates to an air cushion lift device and its applications.
• Modern technology requires ever greater precision, especially in the field of measurement and dimensional control machines for which the errors introduced by the support during movement must be less than the tolerances of the part to be checked.
• One technique which is particularly suitable for moving parts relative to one another without friction is that which uses air cushions.
• the machine comprises a structure that can be moved relative to a solid granite base having at least two perpendicular surfaces, the structure being provided with particular pads.
• These pads consist of conical supports having a substantially circular bearing surface disposed opposite one of the faces of the granite base.
• a number of annular grooves are provided on this face of the skate. These concentric grooves taken from the outside have different functions.
• the external grooves are subjected to pressurized air while several successive concentric grooves inwards are subjected to a fluid under vacuum, the groove closest to the center being brought to atmospheric pressure.
• the different grooves, bringing either the pressurized fluid or the vacuum fluid, are connected together by communication grooves so that the fluid is distributed equally between the different grooves of the same category.
• the supply of pressurized fluid is carried out from the bottom of the throat. These gorges are divided into three portions corresponding to a third of the perimeter. The concentric portions being supplied by a single point.
• the system known from the prior art is used with a control center for the supply of pressurized fluid and the evacuation of the vacuum fluid, which is sensitive to external agents and whose operation is complex. This systematically generates variations in the height of flight of the skate relative to the granite base.
• Another disadvantage of the system of the prior art is that of requiring a supply of pressurized fluid from the bottom of a groove which creates an air film of relatively large height at the level of the throat, this air s' escaping under the surfaces delimiting the groove without it being possible to precisely control the height of this air film.
• the slightest defect in the flatness or machining of the groove causes a localized vanishing point instead of being distributed, which causes a defect in the stability of the skate, so that the distribution into three sectors at 120 ° does not provide this.
• skate the desired stability Indeed, the sector, having a localized vanishing point, will cause the skid to tilt to the side of this sector, the other two cannot compensate for this defect.
• the result is that the skate is not perfectly parallel to the face opposite the granite base.
• skate consists of several mechanical parts assembled to each other by assemblies with no screws which can in no case be compared to an embedding which can also cause inaccuracies.
• the present invention overcomes the drawbacks of the systems of the prior art and proposes a device support structure in which the guidance function is integrated into the structure itself as well as the preload necessary for its operation, which does not introduce any flexible swiveling element, whose geometric precision of the elements allows very low flight heights to be obtained which ensure a high rigidity of the air cushion, whose on-board masses of the system are low but whose moments of inertia are very large, which has great stability with respect to thermal disturbances, which does not induce any friction and therefore no wear of the functional guide parts, and which also exhibits no operating hysteresis.
• the present invention also relates to the specific applications of this lifting device and in particular a device for translational movement, a device for rotational movement and a support device, in particular for measuring instruments.
• the air cushion lifting device in particular for high precision dimensional measurement and control machines, comprises a stand having at least one flat surface, at least one rigid mobile comprising at least one flat face arranged opposite the flat surface of the stand, characterized in that the functional surface for guiding the flat face of the mobile facing the stand is divided into independent sectors by grooves, each of these sectors comprising at least a calibrated nozzle supplied with pressurized or vacuum fluid so as to allow high precision guidance of the mobile relative to the stand.
• the arrangement of sectors and their geometric shape are established according to the geometry of the mobile.
• the supply of pressurized fluid takes place at a constant and predetermined pressure.
• the vacuum is obtained by a vacuum pump comprising a venturi subjected to the constant and predetermined supply pressure.
• the area of the sectors is a function of the size of the nozzles and of the constant and predetermined supply pressure.
• the supply of pressurized fluid is carried out at a pressure between 5 and 7 bars.
• the lifting device is characterized in that it comprises means for closing the supply of pressurized fluid so as to immobilize the mobile relative to the stand.
• the stand and the mobile are made of granite, of dense ceramic of the alumina or silicon carbide type, or of composite material or more generally of any material of low density and having a large Young's modulus.
• the translational displacement device which implements this lifting device, comprises a solid reference stand having at least a first and a second perpendicular face, a square guided relative to these two faces by means of sectors independent spares on the face of this square located opposite the stand and separated by grooves, each of these sectors comprising at least one nozzle calibrated and supplied with fluid under pressure or vacuum so as to allow movement in translation along a first axis "x".
• the square comprises three rectilinear elements joined together to form a U, the first and the second elements being parallel to the first face of the stand, the third element being located in a plane perpendicular to the plane defined by the first and second elements and parallel to the second face of the stand.
• the displacement device is further characterized in that it comprises a movable plate, guided relative to the stand and relative to the bracket, comprising a first and a second face, each provided with independent, separate sectors. by grooves, each of these sectors comprising at least one nozzle calibrated and supplied with fluid under pressure or under vacuum so as to allow movement in translation along a second axis "y" perpendicular to the first axis "x".
• the movable plate is guided relative to the first element of the bracket.
• the translational movement device is further characterized in that the stand comprises a jib projecting above its first face on which is fixed a beam comprising at least two perpendicular faces, whose longitudinal axis is perpendicular to the first face of the stand, this beam supporting a carriage movable along the longitudinal axis of the beam so as to allow movement in translation along a third axis "z" perpendicular to the first and second axes, respectively "x" and "y".
• the carriage comprises two perpendicular elements, joined together to form an L, each of the elements comprising on its face opposite the beam independent sectors separated by grooves, each of these sectors comprising at minus one nozzle calibrated and supplied with pressurized or vacuum fluid.
• the bracket is provided with a counterweight connected to the carriage so as to compensate for the self-weight of the carriage.
• the displacement device is characterized in that the sectors of each of the first and second elements of the bracket, the first face of the movable plate and the first element of the carriage are of the "plate” type, juxtaposed in a central vacuum zone and a peripheral pressure zone.
• the sectors of the third element of the bracket, of the second face of the plate, and of the face of the second element of the carriage are of the "coul isseau” type, juxtaposed in two pressure zones and a vacuum zone respectively disposed at ends and in the middle of the element or face.
• the rotary displacement device using the lift device according to the invention is characterized in that it comprises a stator and a rotor, lifting means of the "disc” type and means for radially guiding the rotor relative to the stator.
• the lifting means comprise a functional surface formed on the stator, and divided into at least two concentric rings separated by grooves, each ring also being divided into independent sectors by grooves and each comprising at least one calibrated nozzle and supplied with fluid. under pressure or under vacuum.
• the stator comprises three concentric crowns, juxtaposed, the sectors of the two inner and outer crowns and the sectors of the intermediate crown being supplied respectively with fluid under pressure and with fluid under vacuum.
• the grooves separating the different crowns are put at atmospheric pressure.
• the means for radially guiding the rotor with respect to the stator comprise a reference sphere rigidly fixed on the rotor and at least three pads arranged at 120 ° and fixed on the stator opposite the sphere.
• the face of each skate opposite the sphere comprises a hemispherical cap comprising at least one pressure zone.
• the face of each pad facing the sphere comprises a coating obtained by prior overmolding on the reference sphere.
• the pads are articulated relative to the stator.
• the support device in particular of a measuring instrument such as a comparator, implementing the lift device according to the invention com takes a shoe movable on a reference surface whose lower face is divided into independent sectors by grooves, each of the sectors comprising at least one nozzle calibrated and supplied with fluid under pressure or vacuum and a support integral with the shoe.
• the independent sectors are of the "plateau" type, juxtaposed in a central vacuum zone and in a peripheral pressure zone.
• FIG. 1 represents a perspective view of the device for translational movement according to the invention
• FIG. 2 represents a perspective view of the bracket and the movable plate according to the invention
• FIG. 3 represents a perspective view with partial section of the lift device according to the invention
• FIG. 4 represents a top view of the stator of the rotary movement device according to the invention
• FIG. 5 represents a sectional view along line 5-5 of FIG. 4,
• FIG. 6 represents a bottom view of the stator with partial section
• FIG. 7 shows a detailed view of a shoe of the rotary movement device according to the invention.
• FIG. 8 represents a perspective view of the support device according to the invention and, FIG. 9 represents a bottom view of the support device of FIG. 8.
• Figure 1 is shown a perspective view of the translational movement device according to the invention.
• This device comprises a solid stand 10, a bracket 12, as well as a bracket 14.
• the solid stand 10 is made of granite and has at least a first face 16 and a second face 18 perfectly ground and of a flatness not causing a defect greater than 5 microns. Furthermore, the faces 16 and 18 are perfectly perpendicular.
• the bracket 12 is shown in more detail in Figure 2. It consists of three elements 20, 22, 24 interconnected so as to form a U. Two of the elements 20 and 22 are parallel to each other and arranged in screws â screw of the first face 16 of the stand 10. The third element 24 is arranged in a plane perpendicular to the plane comprising the first and second elements, respectively 20 and 22, so that this third element is parallel to the second face 18 of the stand 10 More particularly, the three elements 20, 22 and 24 are produced from hollow dense ceramic tubes, of rectangular section for the elements 20 and 22 and of substantially square section for the third element 24.
• connection method is a fast operation and ensures perfect rigidity of the assembly, the connection being able to be considered as an installation. Furthermore, bonding allows very precise positioning of the elements with respect to each other.
• the lift device according to the invention is described below for the "tray” type.
• FIG. 2 represents a perspective view with partial section of an element.
• the first element 20 of the bracket 12 has a planar face 30 disposed opposite the stand, which determines a functional guide surface in which two lift devices of the "tray" type are provided.
• Each device comprises a substantially square surface which is divided into independent sectors 32 each comprising a nozzle 34 perfectly calibrated and supplied with fluid under pressure or under vacuum by a network of flexible conduits, not shown for simplification of the drawing but within the scope of the those skilled in the art, only the connections 36 for supplying fluid under pressure and 38 for supplying fluid under vacuum being shown on the third element 24.
• the sectors are independent and separated by grooves 40 which delimit these sectors and open onto the sides of the square surface.
• Each nozzle 34 comprises a bore 42 formed in the thickness of the element 20 while a throttle 44 whose central passage orifice is perfectly calibrated is introduced from the inside of the element in this bore 42, FIG. 3 showing a portion of one of the flexible conduits 46 of the distribution network of the pressurized fluid.
• the lifting device of the "platform" type has a particular geometry with several sectors 32 supplied with pressurized fluid arranged at the periphery while the central zone is a sector of larger dimensions and in which there is provided a through duct 47 capable of leading a fluid in depression.
• the second device of the "tray" type of the first element 20 and the single device of the element 22 are identical to the tray device which has just been described.
• the first element 20 has a length greater than the second element 22.
• the lifting device of the "slide" type provided on the third element 24 of the bracket 12 also comprises independent sectors 32 and separated by grooves 40. Taking into account the geometry of the bracket. and of its operation as will be described later, the sectors 32 are arranged at the ends 50 of the third element 24, as can be seen in FIG. 2.
• the sector supplied with fluid under vacuum is in the central position between the sectors 32 supplied with pressurized fluid.
• the supply of pressurized or vacuum fluid is carried out from a pneumatic power station comprising in a known manner a filter as well as a vacuum pump device provided with a venturi so that the pressure circulating in a first circuit generates simultaneously during its passage through the venturi system, a depression in a second circuit.
• This vacuum is directly calibrated so that for a supply at constant and predetermined pressure, the central unit delivers to the lift device a constant supply pressure as well as a constant vacuum.
• the area of the sectors is a function of the size of the nozzles and the constant and predetermined supply pressure.
• the supply can be between 5 and 7 bars so as to remain within the current values of supply of pressurized gas in industry.
• the vacuum will be calibrated to reach values between 0.5 and 1 bar.
• the translational movement device is also supplemented by a movable plate 52 comprising a first face 54 facing the first face 16 of the stand 10 and a second face 56 perpendicular to the first face 54 and disposed opposite the 'one of the side faces 58 of the first element 20 of the bracket 12.
• the first face 54 of the movable plate comprises a lifting device of the "plate” type 26 while the second face 56 comprises a lifting device of the "slide” type 28.
• the different faces are shown in detail in FIG. 2 while the mounting as it stands present during operation is shown diagrammatically in FIG. 1.
• the translational movement device comprises a bracket 14 projecting above the first face 16 of the stand 10 on which is fixed a beam 60 which appears to be elepepedic, the longitudinal axis of this beam being oriented perpendicular to the first face 16 of the stand 10.
• the fixing of this beam 60 relative to the bracket is carried out on two of its faces, thus leaving two faces 62 and 64 free.
• a carriage 66 movable along the longitudinal axis of the beam.
• This carriage 66 comprises two elements 68 and 70 joined together to form an L, each of the elements comprising on its face opposite the faces 62 and 64 of the beam 60 of the independent sectors, of the "tray” type for the element. 70 and of the "slide” type for the element 68.
• a counterweight is provided connected to the carriage, not shown but whose production is within the reach of man. art.
• the translational displacement device shown in FIG. 1 can also be supplemented by a rotational displacement device which will be described later.
• the bracket is arranged on the stand 10 so that the face 30 of the first element 20 faces the first face 16 of the stand 10.
• the face of the third element 24 carrying the vacuum device of the " slide "28 is disposed opposite the second face 18 of the stand 10.
• the movable plate 52 is also arranged so that its first face 54 faces the first face 16 of the stand 10, while its second face 56 comes to the contact of the lateral face 58 of the first element 20 of the bracket 12.
• the bracket 12 moving simultaneously relative to the first face 16 and the second face 18 of the stand 10 allows a displacement of the bracket 12 along a first axis "x".
• the movable plate 52 moving along the first element 20 ensures a movement along a second axis "y" perpendicular to the first axis "x” thus defining a table with crossed movement.
• the bracket 14 and beam 60 device allows movement of the carriage 66 along the longitudinal axis of the beam 60 which is perpendicular to the first face 16 of the stand 10 which leads to having a third degree of freedom corresponding to a movement along a third axis "z" perpendicular simultaneously to the first and second axes "x" and "y".
• the displacements of the various elements with respect to the stand or with respect to the beam are obtained by means of the lifting device according to the invention, the operation of which is described more particularly with reference to FIG. 3.
• the pressurized fluid is supplied by the flexible conduit 46, passes through the choke 44, perfectly calibrated, to exit through the bore 42.
• the pressurized fluid, leaving the nozzle 42 is distributed over the entire surface of the sector 32, in particular thanks to the groove 48 which improves the homogeneity of the distribution.
• An air space is created between each of the sectors 32 and the face of the stand which is opposite.
• the grooves 40 avoid the disturbance of an air gap generated by a sector by the air gap generated by a juxtaposed sector.
• grooves 40 are brought to atmospheric pressure by opening laterally on the edges of the lift devices.
• the central sector 32 subjected to a vacuum fluid, it causes a suction cup effect which does not disturb the sectors subjected to the fluid under pressure because the grooves 40 are interposed between the two types of sectors.
• the various moving parts are balanced on an air cushion relative to the fixed element under the action of attractive forces corresponding to the sectors in depression and repulsive forces corresponding to the sectors in pressure.
• the arrangement of the sectors and their geometric shape are a function of the geometry of the mobile and the area of these sectors is a function of the caliber of the nozzles and of the constant and predetermined supply pressure which simultaneously defines the depression thanks to the venturi system.
• the installation of such a translational displacement device is simple since it suffices to arrange the different parts relative to the stand and then to connect the main sheath of the pneumatic wiring to a constant and predetermined pressure source.
• a rotary displacement device which comprises a stator 110 and a rotor 112.
• the stator 110 comprises an annular part 114 surmounted by a disc 116 with a bore 117 in its central part.
• three supports 118 for skids 120 are also provided, as is best shown in FIG. 6 which is a view from below.
• Hinges 122 are also provided, adjustable in translation relative to the supports 118 so that the skate head 124 is adjustable.
• the disc 116 comprises a lifting device according to the invention and it is shown in detail in FIG. 4.
• the lifting device is of the "disc” type and comprises three concentric rings 126, 128 and 130 respectively external, intermediate and internal. These three crowns are separated by grooves 132 so as to delimit two pressure zones corresponding to the outer 126, inner 130 crowns and a depression zone cor corresponding to the crown 128.
• the pressure crowns 126 and 130 are divided into independent sectors 134, separated by grooves 136, the grooves 136 allowing the separation groove 132. to be brought to atmospheric pressure.
• the inner crown is separated into independent sectors 134 by grooves 136 which open inwards into the bore 117.
• the sectors 134 have a defined surface and geometry and each sector is provided with a nozzle 138 which comprises the same elements as the nozzle 34 shown in FIG. 3, namely a flexible conduit 46, a throttle valve 44 opening into a bore 42 formed in the thickness of the disc 116. Similarly, the nozzle is completed by a curved groove 140 which allows better diffusion of the fluid under pressure.
• the intermediate ring 128 includes nozzles 142 which conduct the fluid under vacuum and in the example shown the nozzle 142 is calibrated but the vacuum is determined by the source itself as will be detailed during the description of the operation of the device. displacement in rotation.
• the rotor 112 comprises a solid disc 144 whose surface 146 disposed opposite the disc 116 is perfectly flat and lapped.
• This disc 144 includes inserts 148 on which the parts to be checked can be fixed.
• an axis 150 integral with the disc at one of its ends and supporting at the other end a reference sphere 152.
• This reference sphere has a sphericity such that the diameter in the work area has deviations of the order of ten microns.
• the length of the axis 150 is such that the sphere is disposed between the heads 124 of the three pads 120 when the disc 144 rests on the disc 116 of the stator 110.
• the head 124 of the shoe 120 is adjustable in translation precisely by means of a screw-nut device 154 but the precision of the device is also due to the fact that the heads 124 of the shoes, as shown in detail in FIG.
• the hemispherical cap 160 has a bore 162 through which pressurized fluid passes, the peripheral sealing being produced by means of a seal 164 interposed between this hemispherical cap and the support 156.
• the network of flexible conduits enabling the various nozzles and bores to be supplied is not shown because it is within the immediate reach of those skilled in the art.
• the skate heads 124 are adjusted so as to come in close proximity to the reference sphere 152. These adjustments are made using the screw-nut system 154. Air under constant pressure and at a predetermined value is sent by the nozzles 138 towards each of the sectors 134 of the outer 126 and inner 130 crowns, while fluid under vacuum passes through the bores 142.
• each of the pressure and vacuum zones works independently of each other since the grooves 132 and 136 make each of the rings and each of the sectors respectively independent of each other.
• the radial guide means 119 are then actuated in order to center the disc 144 and the part which it supports with respect to the stator 110.
• pressurized air is sent through the hemispherical cap 160 by l '' bore 162, this introduction of pressurized fluid having the effect of centering the reference sphere 152.
• the arrangement of three pads 120 to 120 ° therefore allows the sphere to be perfectly centered.
• the pressurized fluid is distributed at a constant and predetermined pressure.
• This fixed pressure made it possible to determine the geometric shape and the dimensions of the sectors 134 as well as the size of the nozzles 138, knowing the self-weight of the rotor as well as that of the parts capable of being controlled by means of the rotary displacement device which has just been described.
• the load variations only introduce very small variations in the flight height.
• a rotary displacement device provided with a disk 144 of approximately 300 mm in diameter will only undergo a variation in flight height of 1 micron for a load of approximately 30 kilo.
• the pressure used is around 6 bars and the vacuum around 0.5 bars.
• the rotary displacement device according to the invention can be connected to the current industrial network by a pneumatic central unit grouping together the various elements necessary for adjusting the system, a pressure gauge, a filter as well as a vacuum pump of the venturi type, the vacuum being directly calibrated within the pneumatic unit.
• the precision of the radial guidance is five times greater than the precision of sphericity of the reference sphere.
• the radial guidance is independent of the axial guidance so that it is possible to use large rotors which have a large load capacity without varying the accuracy.
• This precision is linked to the flatness defect in the functional surfaces of the rotor and the stator, this flatness defect being controllable and on the other hand to the action diameter of the outer crown under pressure which is therefore increased. It should also be noted that this effect results from the fact that the increase in diameter is predominant with respect to the flatness defect generated.
• the accuracy of radial centering can be further increased by using pads of larger surface area or alternatively pads with double hemispherical cap so that there are six pad heads, each pair of heads being articulated relative to a support.
• Means for interrupting the supply of pressurized fluid can be interposed on the network of flexible conduits so as to interrupt this supply of fluid on demand. This interruption makes it possible to block the disc 144 of the rotor relative to the disc 116 of the stator so that the rotor is immobilized, which facilitates the loading or unloading of the part to be checked on the rotor in particular.
• the pads can be reduced to two, each of the pads comprising a pressure zone and a vacuum zone, in a similar manner to the arrangement provided on the disc 116 of the stator so that the sphere of reference is only guided by two pads, generating themselves the forces of attraction and repulsion.
• Such a variant is of great interest in the case where space is limited and in the case where the restoring forces must not be too great.
• FIG 8 there is shown a support device according to the invention which comprises a shoe 210, movable relative to a stand 212, this shoe 210 being provided with a support 214 secured to the shoe.
• the support 214 comprises a bracket 216 which supports a comparator 218.
• the bracket 216 is adjustable in height with respect to the support 214 by means of a knurl 220 which actuates in a known manner a screw blocking the bracket 216 with respect to the support 214.
• the shoe 210 comprises on its face 222 opposite the stand 212 a lifting device of the "tray" type comprising sectors 224, independent, separated by grooves 226 opening out on the edges of the tray. Each sector is further provided with a nozzle 228 and a complementary groove 230. Each nozzle 228 is connected by a flexible conduit, not shown, to a general supply conduit 231, shown in FIG. 8, which supplies fluid under pressure each of the nozzles 228. Likewise, a general flexible conduit 232 opens directly at the center of a sector 234 by means of a nozzle 236 so as to bring the entire central zone into depression. This central zone is surrounded at the periphery of the succession of sectors 234 which constitute a pressurized zone.
• the shoe 210 is made of a material with a high Young's modulus, of the granite or ceramic type, depending on the dimensions, while the support, the bracket and the other elements can be made of steel.
• the shoe 210 can be provided on one of its lateral faces with a lifting device of the "slide" type which moreover allows a translational movement of this shoe relative to a reference rule, so that it is also possible to carry out straightness checks without parasitic error due to shock and friction.
• the lifting device according to the invention has a large number of advantages due to the fact of the integration of the different sectors directly into the mass of the element to be moved.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Machine Tool Units (AREA)
• Magnetic Bearings And Hydrostatic Bearings (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9396622

Family Applications (1)

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Cited By (1)

Citations (13)

Family Cites Families (2)

• 1990
  • 1990-05-15 FR FR9006047A patent/FR2662220A1/fr active Granted
• 1991
  • 1991-05-14 WO PCT/FR1991/000388 patent/WO1991018218A1/fr unknown
  • 1991-05-14 AU AU79654/91A patent/AU7965491A/en not_active Abandoned

Patent Citations (13)

Non-Patent Citations (2)

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