GB2160975A - Coordinate measuring instrument - Google Patents
Coordinate measuring instrument Download PDFInfo
- Publication number
- GB2160975A GB2160975A GB08512040A GB8512040A GB2160975A GB 2160975 A GB2160975 A GB 2160975A GB 08512040 A GB08512040 A GB 08512040A GB 8512040 A GB8512040 A GB 8512040A GB 2160975 A GB2160975 A GB 2160975A
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- United Kingdom
- Prior art keywords
- measuring instrument
- movable
- coordinate measuring
- movable member
- detector
- Prior art date
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/02—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness
- G01B21/04—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness by measuring coordinates of points
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices With Unspecified Measuring Means (AREA)
- A Measuring Device Byusing Mechanical Method (AREA)
- Magnetic Bearings And Hydrostatic Bearings (AREA)
Abstract
A coordinate measuring instrument has a workpiece support table 1 and a detector 3 which is mounted on a frame 2 and is movable in the direction of X, Y and Z axes relative to the table 1 to enable dimensions of the workpiece to be measured. Pneumatic bearings are interposed between members 42, 43 on legs 5, 6 of the frame 2 and the table 1 to enable the detector to move in the Y direction. The air bearing surfaces extend over at least 50% of the length and preferably the whole of the facing surfaces of the member 42 and the top surface of the table 1 and of the member 43 and the top 41A and side 41 B of a guide 41. Owing to this extent of the air bearing surfaces, which is much greater than is conventional, the measuring accuracy of the instrument is prevented from being lowered as happens in conventional instruments because of deformation of the members 42 and 43 and other movable parts under the action of gravitational forces. The table may be supported by air bearings for X, Y movement. <IMAGE>
Description
SPECIFICATION
Coordinate measuring instrument
This invention relates to coordinate measuring instruments, and is especially concerned with a movable member which forms part of the instrument and, in operation, moves a detector to generate a detection signal in relation to a workpiece being measured in tri-axial directions.
A coordinate measuring instrument is already known, wherein a detector such as a touch signal probe or the like is supported by a movable member in a manner to be movable in tri-axial directions, that is along mutually perpendicular X, Y and Z axes. Displacement values of the detector are detected in the directions of the axes while the detector is moved in contact with a workpiece on a mount, and these values are processed for measurement, inspection or for recording other data about the workpiece. Measuring instruments such as this have been utilized in a wide range of fields. One such coordinate measuring instrument has a so-called gatetype support.
Figure 1 of the accompanying drawings shows a conventional gate-type coordinate measuring instrument. In this Figure, the top face of a table or mount 1 forming a stationary member, is very smoothly finished. A workpiece to be measured, not shown, rests on this top face which supports a detector 3 such as a touch signal probe through a movable member 2 in a manner such that it is movable in the tri-axial directions. The movable member 2 includes a gate-type support 4 spanning over the workpiece resting on the mount 1. This gate-type support comprises legs 5 and 6 which are disposed at opposite sides of the mount 1 and a beam 7 extending between the legs 5 and 6. Movably supported by the beam 7 in the direction of the X-axis is an X-axis slider 8, which supports a Z-axis slider 9 in a manner to be movable in the direction of the Z-axis.The detector 3 is secured to the bottom end portion of the Zaxis slider 9. One 5 of the legs 5 and 6 is made freely movable on the top face of the mount 1, and the other leg 6 is guided by a guide rail 11 extending in the direction of the
Y-axis, whereby the gate-type support 4 is provided on the mount 1 in a manner to be movable to and fro in the Y direction. The bottom end portions of the legs 5 and 6 are formed into bottom end support portions 1 2 and 1 3 which are elongated in the Y direction whereby, even while the gate-type support 4 is moving in the Y direction, the vertical position of the gate-type support is held stable.
As shown in Figure 2, one of the bottom end support portions 1 2 is provided at opposite ends thereof with pneumatic bearing devices 1 5. As shown in Figures 3 to 5, this pneumatic bearing device 1 5 is constituted by an air pad 1 6 formed separately from the bottom end support portion 12, a mounting member 1 7 and a connecting nozzle 1 8 forming an air feed connector. The air pad 1 6 is formed in the central portion of a mounting surface thereof to be mounted to the bottom end support portion 12 with a recess 21, provided above an air blow-out surface 22 thereof facing the mount 1 with a plurality of air blow-out holes 23 each having a very small diameter (e.g. about 0.2 mm or less).
The holes 23 are arranged in a checkerboard fashion, and further the pad 1 6 is formed therein with a connecting space 24 communicating with the air blow-out holes 23, whereby compressed air introduced into the connecting space 24 through a connecting piece 18 is fed to the respective air blow-out holes 23. Although the distribution density of the air blow-out holes 23 is shown to be rather sparse on the surface 22 in actuality the air blow-out holes 23 are arranged very densely.
The mounting member 1 7 is mounted in the recess 21 of the air paid 16 and is formed in the central portion of the upper surface thereof with an engaging recess 28 having a conical surface for supporting a ball 27 interposed between the bottom end support portion 12 and the member 17.
Furthermore, in the bottom end support portion 13, pneumatic bearing devices 1 5 constructed similarly to the above are interposed between the top face of the guide rail 11 and the bottom end support portion 1 3 and between the opposite side surfaces of the guide rail 11 and the bottom end support portion 13 as shown in Figure 6. These pneumatic bearing devices 1 5 are provided at the longitudinally opposite end portions of the bottom end support portion 1 3 similarly to the case of the bottom end support portion 1 2 (refer to Figure 2).
The conventional construction as described above has nevertheless the following disadvantages:
(1) Since the pneumatic bearing devices 1 5 are provided at the longitudinally opposite end portions of the bottom end support portions 1 2 and 13, respectively, deflections tend to occur in the Z direction when a load W of the movable member 2 acts from the leg 5 on the intermediate portion of the bottom end support portion 1 2 or 1 3 as shown diagrammatically in Figure 7, whereby fluctuating deflections are applied to the detector 3 in the Z direction thus resulting in lowered accuracy of the detector 3 in the Z direction.
(2) The area of the air blow-out surface 22 of the pneumatic bearing device 1 5 is determined by the load W and by the pneumatic pressure blown out of the air blow-out holes 23 and has a predetermined size. However, when the pneumatic bearing devices 1 5 are provided only at the longitudinally opposite end portions of the bottom end support portions 1 2 and 13, the air blow-out surface 22, i.e. the dimension in the widthwise direction of the bottom end support portions 1 2 or 1 3 is increased as shown in Figure 2, whereby, in operation of the gate-type support 4 mounted on the mount 1, the effective space (i.e. the dimension I in the widthwise direction as shown in Figure 2) is reduced as compared with the case where the air blow-out surface 22 is not used.This situation is more notable when the measuring instrument is large-sized and the load W is therefore also large.
(3) In order to obviate the error in the Z direction it is possible to make the structure of the gate-type support 4 very rigid. In this case, however, the width of the air blow-out surface 22 is further increased due to the increased weight. The increase of weight is not therefore acceptable.
(4) In determining the area of the air blowout surface, only the balance between the pneumatic pressure and the load has heretofor been considered. Because of this, undesirable movements towards the movable member in directions other than the guided directions, resulting for example from vibrations, shifts in positions, inclinations and the like can easily be induced.
In these circumstances, the above-described conventional structure has not been able to meet the requirements of the provision of a coordinate measuring instrument which has both high accuracy and is of large size.
An object of the present invention is to provide a coordinate measuring instrument in which the movement of a movable member relative to a stationary member can be effected smoothly, thus avoiding to the utmost lowered measuring accuracy due to deformation of the movable member and thus enabling highly accurate measurement to be made even when the measuring instrument as a whole is large-sized and very heavy in weight.
To this end, according to this invention we provide a coordinate measuring instrument comprising a workpiece support, a detector, means for moving the workpiece support and the detector relative to each other in the directions of X, Y and Z axes and means for indicating the magnitudes of the relative movements in the said directions to measure dimenions of the workpieces, wherein a stationary member and a movable member, one of which supports the workpiece support and the other the detector, are movable relative to each other in the direction of one of the axes through a pneumatic bearing device or devices which support the movable member from the stationary member, the bearing device or devices having a total bearing surface area, over which air is supplied under pressure and is blown out, extending in a horizontal plane over a length equal to 50% or more of the length, in the direction of relative movement of the members, of a surface of the movable member which faces the stationary member, and extending over the whole width of the said surface of the movable member in a direction perpendicular to the direction of the said relative movement.
In short, to achieve the above-described object, the present invention contemplates that the area of the air bearing surfaces in the pneumatic bearing devices shall exceed a predetermined value, so that the movement of the movable member relative to the stationary member can be smoothly performed and the movable member cannot be easily deflected by the dead load of the movable member itself.
Some examples of instruments in accordance with the invention will now be described with reference to the accompanying drawings in which:
Figure 1 is a diagrammatic perspective view showing the general arrangement of a conventional coordinate measuring instrument;
Figure 2 is a diagrammatic bottom plan view showing an example of a conventional pneumatic bearing device in the instrument of
Figure 1;
Figure 3 is a partially cut-away plan view of the conventional pneumatic bearing device;
Figure 4 is a partially cut-away front view of the conventional pneumatic bearing device;
Figure 5 is an underneath view of the conventional bearing device;
Figure 6 is a front view showing a bottom end support portion on one side of a guide member of the conventional instrument;;
Figure 7 is a diagrammatic side view showing a deflected condition of the bottom end support portion in the conventional instrument;
Figure 8 is a diagrammatic perspective view showing the general arrangement of a first example of a coordinate measuring instrument in accordance with the present invention;
Figure 9 is a diagrammatic bottom view corresponding to Figure 2, but showing the pneumatic bearing device in the example of
Figure 8;
Figure 10 is a partially cut-away front view showing the pneumatic bearing device in the example of Figure 8;
Figure 11 is a bottom view showing the pneumatic bearing device in the example of
Figure 8;
Figure 1 2 is a partially cut-away front view showing a bottom end support portion on the side of a guide member in the example of
Figure 8; ;
Figure 1 3 is a side view corresponding to
Figure 7, but showing the condition where a load is applied to the bottom end support portion shown in Figure 12;
Figure 14 is a diagrammatic perspective view showing the general arrangement of a second example of a coordinate measuring instrument in accordance with the present invention;
Figures 1 5 and 1 6 are partially cut-away front and bottom views showing a mount or table in the second example;
Figure 1 7 is a diagrammatic perspective view showing the general arrangement of a third example of a coordinate measuring instrument in accordance with the invention;
Figure 1 8 is a sectional view of portions of the third example;;
Figure 1 9 is a diagrammatic perspective view showing the general arrangement of a fourth example of a coordinate measuring instrument in accordance with the invention;
Figure 20 is a front view showing a fifth example of a coordinate measuring instrument in accordance with the invention; and,
Figure 21 is a bottom view showing a modification of a bottom end support portion of the example shown in Figure 20.
Descriptions will now be given of the examples of the present invention with reference to the drawings. The same reference numerals are used to designate parts which are the same as or correspond to parts in the conventional construction to simplify the description.
Referring to Figure 8, bottom end support portions 42 and 43 of legs 5 and 6 are formed to have widths narrower than those in the conventional construction. An air bearing or blow-out surface 52 of a pneumatic bearing device 55 provided on the bottom end support portion 42 has a length along its direction of the movement (the Y direction) equal to 100% of the total length T in the aforesaid direction of movement of the bottom end support portion 42 (see Figure 9). Furthermore, the total area of the air bearing or blowout surface 52 is determined by the total load applied to the member 42 by the movable member.Since the length of the air blow-out surface 52 in the aforesaid direction of movement is made equal to 100% of the length T of the bottom end support portion 42 in the direction of movement, the dimension W, in the widthwise direction of the air blow-out surface 52 is minimised in comparison with the same air blow-out area in the conventional construction, whereby the width W1 of the bottom end support portion 42 is also minimised.
As shown in Figures 10 and 11, the air blow-out surface 52 is directly formed on the bottom end support portion 42. Thus, in this example the whole area of the bottom end surface of the bottom end support portion 42 is made to be an air bearing or blow-out surface 52. A plurality of air blow-out holes 53 are arranged in checkerboard fashion that is in a rectangular array, in the air blow-out surface 52. Further, a connecting space 54 communicating with the air blow-out holes 53 is provided in the bottom end support portion 42 and compressed air is introduced from an external air supply source, not shown, into the connecting space 54 through a connecting nozzle 56. This compressed air is then blown out through the air blow-out holes 53. In actuality the air blow-out holes 53 are distributed far more densely than is shown in the drawings.
Furthermore, the bottom end support portion 43 of the other leg 6 is guided in the Y direction by a guide member 41 of square cross-section which is fixed on the mount or table 1 and forms a stationary member. As shown in Figure 1 2 the bottom end support portion 43 is provided with a pneumatic bearing device 55 including three air biow-out surfaces 52 opposed to a top horizontal guide surface 41A and opposite side vertical guide surfaces 41 B of the guide member 41. The air blow-out surfaces 52 of the pneumatic bearing device 55 are made to have a length equal to 100% of the total length T of the bottom end support portion 43 in the Y direction, whereby a dimension W2 in the widthwise direction of the member 41 (the X direction) is minimised (see Figure 9).The width of the upwardly facing air blow-out surface 52 formed directly on the bottom end support portion 43 is also similarly minimised.
According to the example described above, the air blow-out surfaces 52 are provided over the total lengths of the bottom end support portions 42 and 43, so that a dimension of the air blow-out surface 52 in the widthwise direction (the direction X), i.e. dimensions of the bottom end support portions 42 and 43 in the widthwise directions W1 and W2 can be minimised in comparison to the same total air blow-out area with a conventional construction. This has the result that, with the use of the mount 1 having the same overall area, the effective width (the dimension I in the widthwise direction) can be advantageously increased. particularly, when the measuring instrument is large-sized and very heavy, the air blow-out area should be sufficient to support the very heavy weight. However, in the case described above, the effective space on the mount 1 can be made satisfactorily large.
The air blow-out surfaces 52 are provided over the total lengths of the bottom end support portions 42 and 43 in the longitudinal direction. This is preferred, but it is only essential that the air blow-out surfaces shall be 50% or more of the total lengths of the portions 42 and 43, so that deflections of the portions 42 and 43 do not easily occur owing to the load W from the legs 5 and 6, and measuring errors in the Z direction do not therefore easily occur. It is particularly highly advantageous that the measuring accuracy is prevented from being lowered when the mea suring instrument is large-sized and very heavy in weight.
Further, in the above example, the air blowout surfaces 52 are directly formed on the bottom end support portions 42 and 43, so that the measuring instrument can be simplified in construction. A height H of the bottom end support portion 42 can be decreased for example, that is to say it can be made thin (see Figure 13). In view of this, the movable member 2 can be made lighter in weight, so that various disadvantages due to the very heavy weight of the measuring instrument can be reduced. Controllability of the instrument can be improved in measuring the workpiece on the mount 1, and handleability can be improved in mounting and replacing the workpiece on the mount 1.
Furthermore, it is difficult for the leg 6 extending from the bottom end support portion 43 to be inclined from the vertical or to be displaced in a direction connecting the legs 5 and 6 to each other, i.e. the X direction due to the presence of the pneumatic bearing device 55. Thus the very heavy weight of the structure of the gate-type support 4 minimises any shift in position of a scale 7A in the X direction occurring due to a change in load by the movement of an X-axis slider 8. In other words, the vertical state of the leg 6 is firmly held by the pneumatic bearing device 55 of the bottom end support portion thereof, so that the scale 7A in the X direction provided on the beam 7 can be prevented from being shifted in position in the direction X as much as possible.
Description will now be given of the various further examples. The same reference numerals are used to designate the same or similar parts to those in the above example to simplify the description or enable parts of it to be omitted.
Figure 1 4 shows a second example of a coordinate measuring instrument in accordance with the present invention. This example is of such an arrangement that the workpiece mount or support is a movable member and a base for movably supporting this mount and a gate-type support 200 constitute a stationary member. The gate-type support 200 is fixed on a base 100, on which a mount 70 which forms a movable member is supported in a manner to be movable in the
Y direction. Substantially the whole area of the bottom surface of the mount 70 is supported on a horizontal guide surface 80 of the base 1 00. A groove 90 is formed in the horizontal guide surface 80 in the direction of the Y-axis, while, formed on the bottom surface of the mount 70 is a ridge 110 which slides in the groove 90 (see Figure 15).
As shown in Figure 16, substantially the whole area of the bottom surface of the mount 70 is made to be an air bearing or blow-out surface 111, in which air blow-out holes 11 2 each having a predetermined small diameter are arranged in checkerboard fashion for example. Additionally, the actual density of distribution of the air blow-out holes 11 2 is far greater than that shown in the drawings.
The air blow-out holes 11 2 have openings in the air blow-out surface 111 and are connected to a connecting space 11 3 formed in the main body of the mount 70. The connecting space 11 3 is connected to an external air pressure supply source, not shown, so that air at a predetermined pressure can be blown out of the air blow-out holes 11 2 to reduce the sliding resistance of the mount 70 on the base 100. The air blow-out surface 111 formed therein with the plurality of the air blow-out holes 11 2 and the external air pressure supply source for supplying the predetermined air pressure constitute a pneumatic bearing device 140.
According to this example as described above, substantially the whole area of a portion opposed to the base 100 of the mount 70 is formed into the air bearing or blow-out surface 111, so that deformation or deflection of the mount 70 can be substantially reliably avoided. This differs from the conventional arrangement where the mount 70 is mounted on the base 100 with air pads formed separately from the mount 70 and applied to the opposite end portions of the mount 70 in the moving direction of the mount 70. Furthermore, the advantages are offered that the shift in position and inclination or tilting of the mount 70 do not easily occur and small vibrations during movement do not easily occur as well.
Furthermore, the air blow-out surface 111 is directly formed in the mount 70, so that the mount 70 can be made light in weight and thin in thickness. This proves to be highly advantageous from the viewpoint of the handling and economy. Particularly, even when the measuring instrument as a whole is made large-sized, the measuring instrument can be made relatively light in weight. Furthermore, the constituent parts can be made compact in size (or thin in thickness) with the effective space being kept satisfactorily large.
Further the mount 70 is itself made movable to take care of one of the three moving directions required in the instrument. in general, the mount 70 has a form which is spread in the horizontal direction, whereby the mount 70 is very stably movable relative to the base 100. Thus, with the measuring instrument as a whole in view, the measuring accuracy is improved as compared with the example where the mount 70 is fixed and all of the movements in the directions of the three axes are made by the detector.
Figure 1 7 shows a third example in which an intermediate table 1 50 is mounted on a base 100 which forms a stationary member.
The table 1 50 is movable in the direction of the X axis. The mount 70 is mounted on the intermediate table 1 50 in a manner to be movable in the direction of the Y axis. Here, the intermediate table 1 50 and the mount 70 together constitute the movable member. A groove 1 60 is formed in the direction of the X axis in the horizontal guide surface 80 of the base 100, a ridge 1 70 which fits in this groove 1 60 is formed on the bottom face of the intermediate table 150, and a groove 90 and a ridge 110 are formed on a horizontal guide surface 180 forming the top face of the intermediate table 1 50 similarly to the second example.In this way, the workpiece to be measured, not shown, on the mount 70 is movable in the two directions of the X and Y axes which intersect each other perpendicularly on the base 100. Substantially the whole area of the bottom face of the above-described intermediate table 150 (i.e. the part of the intermediate table 1 50 opposed to the base 100 which forms the stationary member) is made to be an air blow-out or bearing surface 1 90. A plurality of air blow-out holes 11 2 are arranged in the air blow-out surface 1 90 in a predetermined fashion as shown in
Figure 18, and the sliding resistance of the intermediate table 1 50 on the base 100 is reduced through the pneumatic bearing device 200 which includes the air blow-out surface 190.
In the third example as described above, a fixed gate-type support 4, which is a structure large in height and weight is not made movable, whereby various drawbacks which may result from movement of the gate-type support 4 are avoided, so that the measuring accuracy can be advantageously enhanced.
Furthermore, in the third example, the mount 70 is made movable in the directions of two of the three axes, whereby it suffices to move the detector 3 only in one direction, that is the direction of the Z axis, on the fixed gatetype support 4, so that the structure of and supported on the fixed gate-type support 4 can be simplified accordingly.
Figure 1 9 shows a fourth embodiment, in which two beams 220 extending in the Y direction are arranged parallel to each other at a predetermined height by fixed supports 210 at opposite sides of the mount 1. The beams 220 each have a guide member 230 of a square or other rectangular cross-section fixed on them. Opposite end portions of a beam 240 extending in the X direction and forming a movable member, while the beams 220 and the mount 1 form a stationary member, are supported on the beams 220 in a manner to be movable in the Y direction through pneumatic bearing devices 250.Similarly to that shown in Figure 12, at opposite end portions of the beam 240 air blow-out or bearing surfaces opposed to a top guide surface 230A and opposite side vertical guide surfaces 230B on the guides 230 are provided over substantially the whole area of the aforesaid opposed portions. On the air blow-out surfaces, there are arranged air blow-out holes in a regular array.
In the fourth example as described above, particularly, it is advantageous that a deformation in the Z directon of the opposite end portions of the beam 240 can be avoided.
Additionally, in the first example a description has been given of the case where the pneumatic bearing devices 55 are directly formed on the bottom support portions 42 and 43. However, the present invention need not necessarily be limited to this. For example, as shown in Figure 20, an arrangement may be adopted in which one of the bottom end support portions 42 is formed into a pneumatic bearing device 1 5 similarly to the prior art.Air pads 1 6 are fixed to a portion of the other support portion 43, which is opposed to the top horizontal guide surface 41A of the guide member 41 and to a portion of the bottom end support portion 43, which is opposed to one of the vertical guide surface 41 B, and the air pads 1 6 are connected through a ball 27 to a portion opposed to the remaining vertical guide surface 41B to thereby constitute the pneumatic bearing device 55. In short, it suffices to adopt such an arrangement that the leg 6 resists inclination and displacement in the X direction, provided that the total air bearing surface has the necessary extent of the full width and at least half the total length of the facing surfaces at the air bearing.As already mentioned, the air blow-out surfaces 22, 52, 111 and 1 90 need not necessarily be equal in length to 100% of the total length of the portion facing the stationary member. For example, referring to the case of the bottom end support portions 42 and 43, the air blow-out surface may be less than 100% as shown in Figure 21.
However, the air blow-out surface must have a length of 50% or more of the support portion. Even if it is considered that air relief path portions or the like are provided on the bottom faces of the bottom end support portions 42 and 43 so as to facilitate the effect of the pneumatic bearing devices, this cannot be expected to decrease the measuring errors in the Z direction if the blow-out surface is of a length of less than 50% of the total length.
Furthermore, when the air blow-out surfaces 52 are directly formed on the bottom support portions 42 and 43, the surfaces on which the air blow-out surfaces 52 are formed are preferably coated with a rust preventive by plasma spray coating, plating or by other techniques. The air blow-out holes 53 need not necessarily be formed individually, but instead a porous member may be assembled into a portion constituting the air blow-out surface 55.
As has been described hereinabove, the present invention may provide a coordinate measuring instrument capable of smoothly carrying out the movement of the movable member relative to the stationary member, effectively preventing the movable member from being deformed due to the weight of the movable member and parts which it carries, and conducting highly accurate measuring even when the measuring instrument as a whole is large-sized and very heavy in weight.
Claims (1)
1. A coordinate measuring instrument comprising a workpiece support, a detector, means for moving the workpiece support and the detector relative to each other in the directions of X, Y and Z axes and means for indicating the magnitudes of the relative movements in the said directions to measure dimensions of the workpieces, wherein a stationary member and a movable member, one of which supports the workpiece support and the other the detector, are movable relative to each other in the direction of one of the axes through a pneumatic bearing device or devices which support the movable member from the stationary member, the bearing device or devices having a total bearing surface area, over which air is supplied under pressure and is blown out, extending in a horizontal plane over a length equal to 50% or more of the length, in the direction of relative movement of the members, of a surface of the movable member which faces the stationary member, and extending over the whole width of the said surface of the movable member in a direction perpendicular to the direction of the said relative movement.
2. A coordinate measuring instrument according to Claim 1, wherein the length of the bearing surface area is equal to the total length, in the direction of relative movement of the members, of the said surface of the movable member.
3. A coordinate measuring instrument according to Claim 1 or Claim 2 wherein the movable member comprises a gate-type support supporting the detector, the gate-type support having two legs one of which is provided with the pneumatic bearing device or devices and is movable on an opposed surface of the stationary member, the other leg is provided with pneumatic bearing devices acting upon a top flat surface and on at least one vertical surface of a guide member which is of rectangular cross-section and is fixed to said stationary member, the member of rectangular cross-section extending in said direction of relative movement, and the other leg being supported on said stationary member in a manner which resists displacement towards the one leg and resists inclination to a vertical direction.
4. A coordinate measuring instrument according to Claim 1 or Claim 2, wherein the pneumatic bearing devices including means for supplying the air under pressure are directly formed on portions of the workpiece support, the portions having the surface which faces the stationary member.
5. A coordinate measuring instrument according to Claim 3, wherein the bottom end of the other leg has a recess receiving said guide member, and surfaces forming the recess are directly formed to form air supply surfaces of the bearing devices which act on the top surface and the vertical surface of the guide member.
6. A coordinate measuring instrument according to Claim 1 or Claim 2, in which the stationary member includes a base and a gateshaped frame erected on the base, and the movable member supports the detector and is movable along a guide member which is fixed to the gate-shaped frame and extends in said direction of relative movement on the upper end of said gate-shaped frame.
7. A coordinate measuring instrument according to Claim 1, Claim 2, or Claim 4, wherein the stationary member includes a base and a pair of gate-shaped frames erected on said base, and said movable member is a mount for supporting said workpiece, said mount being guided by said base.
8. A coordinate measuring instrument according to Claim 1, substantially as described with reference to Figures 8 to 13, or Figures 14 to 16, or Figures 17 and 18, or Figure 19, or Figure 20, or Figure 21, of the accompanying drawings.
CLAIMS
Amendments to the claims have been filed, and have the following effect:
Claims 1 and 2 above have been deleted or textually amended.
New claim 1.
Claims 3-8 above have been renumbered as 2-7 and their appendancies corrected.
1. A coordinate measuring instrument comprising a workpiece support, a detector, means for moving the workpiece support and the detector relative to each other in the directions of X, Y and Z axes and means for indicating the magnitudes of the relative movements in the said directions to measure dimensions of the workpieces, wherein a stationary member and a movable member, one of which supports the workpiece support and the other the detector, are movable relative to each other in the direction of one of the axes through a pneumatic bearing device or devices which support the movable member from the stationary member, the bearing device or devices having a horizontal bearing surface area, over which air is supplied under pressure through individual air supPly holes uniformly distributed over substantially the whole length, in the direction of relative movement of the members, of a bearing sur face of the movable member which faces the stationary member, and uniformly distributed over substantially the whole width of the said surface of the movable member in a direction perpendicular to the direction of the said relative movement to supply air uniformly over the whole bearing surface area.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9581384A JPS60238709A (en) | 1984-05-14 | 1984-05-14 | Three-dimensional measuring machine |
| JP9581184A JPS60238701A (en) | 1984-05-14 | 1984-05-14 | Three-dimensional measuring machine |
| JP9581284A JPS60238702A (en) | 1984-05-14 | 1984-05-14 | Three-dimensional measuring machine |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8512040D0 GB8512040D0 (en) | 1985-06-19 |
| GB2160975A true GB2160975A (en) | 1986-01-02 |
| GB2160975B GB2160975B (en) | 1988-11-09 |
Family
ID=27307916
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08512040A Expired GB2160975B (en) | 1984-05-14 | 1985-05-13 | Coordinate measuring instrument |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE3517421A1 (en) |
| GB (1) | GB2160975B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2263338A (en) * | 1992-01-08 | 1993-07-21 | Rank Taylor Hobson Ltd | Metrological apparatus. |
| US6327788B1 (en) | 1995-12-07 | 2001-12-11 | Taylor Hobson Limited | Surface form measurement |
| EP1413388A1 (en) * | 2002-10-25 | 2004-04-28 | Mori Seiki Co., Ltd. | Machine tool with hydrostatic slideways with variable pressure |
| US6735867B2 (en) * | 1999-02-19 | 2004-05-18 | Nikon Corporation | Method of making a static pressure air bearing |
| WO2012148310A2 (en) * | 2011-04-29 | 2012-11-01 | Общество с ограниченной ответственностью "Лаборатории Амфора" | Aerostatic device for positioning an instrument relative to an object |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2600764A1 (en) * | 1986-06-24 | 1987-12-31 | Applic Mecano Granits | Robot measuring linear dimensions |
| DE3808871A1 (en) * | 1988-03-17 | 1989-09-28 | Mauser Werke Oberndorf | COORDINATE MEASURING MACHINE |
| FR2662220A1 (en) * | 1990-05-15 | 1991-11-22 | Maitre Ateliers | AIR CUSHION SUPPORT DEVICE AND ITS APPLICATIONS. |
| US5241183A (en) * | 1991-03-22 | 1993-08-31 | Nippon Telegraph And Telephone Corporation | Vertical xy stage |
| DE4313458C2 (en) * | 1993-04-24 | 1996-09-05 | Matthias Schum | 3-D coordinate measuring machine |
| DE4328533C2 (en) * | 1993-08-25 | 1997-10-09 | Matthias Schum | Measuring machine |
| WO2019161915A1 (en) * | 2018-02-23 | 2019-08-29 | Güdel Group AG | Area gantry |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1393035A (en) * | 1971-07-09 | 1975-05-07 | Olivetti & Co Spa | Precision measuring apparatus with aerostatic bearings |
| US4155173A (en) * | 1977-05-13 | 1979-05-22 | Sprandel Hans W | Mounting for coordinate measuring machine arms and probes |
| GB1588199A (en) * | 1977-05-26 | 1981-04-15 | Bendix Corp | Coordinate measuring machine |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2346693A1 (en) * | 1973-09-17 | 1975-04-24 | Wotan Werke Gmbh | Air bearing slide for inter mobile machine parts - feeds air to the mobile portion to improve accessibility for cleaning |
| JPS566919A (en) * | 1979-06-26 | 1981-01-24 | Canon Inc | Fluid bearing |
| DE3336002C2 (en) * | 1983-10-04 | 1985-11-07 | Dr. Johannes Heidenhain Gmbh, 8225 Traunreut | Guide device |
-
1985
- 1985-05-13 GB GB08512040A patent/GB2160975B/en not_active Expired
- 1985-05-14 DE DE19853517421 patent/DE3517421A1/en not_active Ceased
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1393035A (en) * | 1971-07-09 | 1975-05-07 | Olivetti & Co Spa | Precision measuring apparatus with aerostatic bearings |
| US4155173A (en) * | 1977-05-13 | 1979-05-22 | Sprandel Hans W | Mounting for coordinate measuring machine arms and probes |
| GB1588199A (en) * | 1977-05-26 | 1981-04-15 | Bendix Corp | Coordinate measuring machine |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2263338A (en) * | 1992-01-08 | 1993-07-21 | Rank Taylor Hobson Ltd | Metrological apparatus. |
| GB2263338B (en) * | 1992-01-08 | 1995-06-14 | Rank Taylor Hobson Ltd | Metrological apparatus |
| US5572798A (en) * | 1992-01-08 | 1996-11-12 | Rank Taylor Hobson Limited | Metrological apparatus |
| US6327788B1 (en) | 1995-12-07 | 2001-12-11 | Taylor Hobson Limited | Surface form measurement |
| US6735867B2 (en) * | 1999-02-19 | 2004-05-18 | Nikon Corporation | Method of making a static pressure air bearing |
| EP1413388A1 (en) * | 2002-10-25 | 2004-04-28 | Mori Seiki Co., Ltd. | Machine tool with hydrostatic slideways with variable pressure |
| WO2012148310A2 (en) * | 2011-04-29 | 2012-11-01 | Общество с ограниченной ответственностью "Лаборатории Амфора" | Aerostatic device for positioning an instrument relative to an object |
| WO2012148310A3 (en) * | 2011-04-29 | 2013-01-10 | Общество с ограниченной ответственностью "Лаборатории Амфора" | Device for positioning an instrument relative to an object |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8512040D0 (en) | 1985-06-19 |
| DE3517421A1 (en) | 1985-11-21 |
| GB2160975B (en) | 1988-11-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19950513 |