WO2012041685A1

WO2012041685A1 - Walkable cover for a coordinate measuring device

Info

Publication number: WO2012041685A1
Application number: PCT/EP2011/065727
Authority: WO
Inventors: Berthold Matzkovits; Roland Brenner; Hartwig VÖHRINGER
Original assignee: Carl Zeiss Industrielle Messtechnik Gmbh
Priority date: 2010-09-29
Filing date: 2011-09-12
Publication date: 2012-04-05
Also published as: CN103238039B; CN103238039A; DE102010046927A1

Abstract

The invention relates to a walkable cover (8) for a coordinate measuring device (1), comprising the following: a) an elongate profiled sheet metal section (18) which has an upper face and a lower face, b) on the lower face of the profiled sheet metal section (18) a height adjustable foot (19a, 19b, 19c, 19d) is attached at least in each of the four corners, by which foot the profiled sheet metal section (18) can be placed on the floor (12) underneath, c) at least one clamping element (20), by which the profiled sheet metal section (18) can be clamped against the floor (12) underneath, and d) a walkable cover plate (9), which is attached to the upper face of the profiled sheet metal section by a releasable attachment (29).

Description

Description;

Walk-in cover for a coordinate measuring machine The invention relates to a walk-in cover for a coordinate measuring machine.

Walk-in covers of coordinate measuring machines are known from the prior art for a long time. These are often used in coordinate measuring machines, in which the measuring table for receiving a workpiece to be measured at ground level can be committed by the operator of the coordinate measuring machine. For this to be possible, the measuring table must be sunk into the ground so that the top of the measuring table lies in the same plane as the floor surrounding the measuring table. This is usually made possible by a recess is provided in the floor, in which a special foundation is stored, on which then the measuring table is stored. In addition, the horizontal guide for the adjustable mechanism of the coordinate measuring machine is mounted below the level of the floor. In the area of the guides usually arise openings that must be closed by walk-in covers.

The German patent application DE 1 8 07 998 AI and the German patent DE 41 16 127 C2, for example, show a coordinate measuring machine, in which the horizontal guides for the stator mechanism of the coordinate measuring machine are arranged in recesses of the measuring table. The recesses for the horizontal guides are each partially covered with a cover plate, which is attached directly to the measuring table. The walk-in cover is very easy to attach in the case of the cited documents. The disadvantage of this, however, is that the guides are already integrated in the measuring table itself. As a result, from the beginning of the relatively simple and inexpensive to manufacture measuring table and the rather expensive to produce and calibrated

Mechanics of the coordinate measuring machine connected to each other.

Therefore, coordinate measuring machines have meanwhile prevailed, in which the horizontal guides for guiding the mechanism are mounted on a separate guide bar, wherein the guide bar is mounted next to the measuring table on the foundation. This allows the measuring table cost and without major transport problems in the Be made close to the customer, which is particularly advantageous if the customer is far away from the manufacturer of the coordinate measuring machine, eg on another continent. The mechanics of the coordinate measuring machine, however, can during

Manufacturers of the coordinate measuring machine are manufactured and calibrated and then transported without major problems to the customer and assembled here.

In the area of the guide beam, however, such a construction creates openings which have to be closed by correspondingly more elaborate covers. The area between the measuring table and the guide bar and also the guide bar itself can be relatively easily provided with a cover. For example, the cover plate, which closes the area between the measuring table and the guide bar can be attached via simple angles on the measuring table. The cover plate above the

Guide bar is also relatively easy to install. In contrast, the mounting of the cover plate, which closes the area between the side of the guide bar facing away from the measuring table and the floor, is difficult. This has the following reason. The coordinate measuring machine is usually mounted so that at the very end of the cover plate is mounted, which closes the area between the measuring table facing away from the side of the guide bar and the floor. Thus, therefore, all previously mounted elements of the coordinate measuring machine can be readily used and mounted. By contrast, the last cover plate, with which the last remaining opening is closed, has to be fitted in a relatively complex manner.

On the one hand, this requires inaccuracies in the horizontal direction, for example, of the foundation, to be compensated. On the other hand, the height of the cover must be aligned so that no tripping occurs.

In the past, a weldment was used for such a cover. The peculiarity of such a construction was that it was relatively material-consuming. In addition, this design required many items, which also had to be elaborately adjusted.

In another cover, horizontal outriggers were mounted on the underside of the guide beam at the ends of which vertical supports were provided. On these supports then a walk-cover plate is attached. The orientation of such a cover is much easier than in the case of those described above

Welded construction, as the booms can be pre-assembled. However, this construction is relatively complex. In addition, this increases the volume of the guide bar, making it difficult to transport the guide bar.

Based on this, our invention is based on the object, a walk-in

Provide cover that is relatively easy to manufacture and can be easily fitted. The object is solved by the features of independent claim 1.

In accordance with the invention, a walk-in cover is proposed for a

To provide a coordinate measuring machine, comprising:

a) an elongated sheet metal profile having a top and a bottom b) on the underside of the sheet metal profile is at least in each of the four corners

attached height adjustable foot over which the sheet metal profile can be stored on the underlying soil

c) at least one clamping element over which the sheet metal profile against the underlying soil is tensioned

d) a walk-cover plate which is attached to the top of the sheet metal profile via a releasable attachment.

Such a walk-in cover has significant advantages. Because of that

Main element of the cover is an elongated sheet metal profile is used, there is an essential part of the walkable cover of a standard component that is easy to produce and thus can be obtained inexpensively. Due to the height-adjustable feet, the height of the accessible cover plate can be adjusted almost without effort, and so dimensional inaccuracies of the foundation or dimensional inaccuracies of the sheet metal profile can be compensated easily. The tensioning element ensures that the accessible cover rests firmly on the floor. In this way, despite the relatively low weight of the walk-in cover can be achieved that the walk-in cover firmly adheres to the floor. Due to the releasable attachment of the cover plate on top of the sheet metal profile is achieved that the cover plate is attached only after the cover was adjusted. As a result, the walk-in cover can first be aligned and only then the cover plate can be mounted on the profile.

The invention may be advantageously developed according to the dependent claims.

Although the clamping element can be provided in principle at any point of the elongated profile, it is recommended to provide a clamping element at least at each of the two ends of the sheet metal profile, because then the clamping force of the clamping element in the area of the feet attacks. As a result, the bending moments occurring between the clamping element and the height-adjustable feet are reduced.

Clamping elements are suitable as clamping elements, by means of which a clamping force can be generated which tensions the elongate profile against the ground. For example, as a tensioner

Clamping device conceivable in which the clamping force is generated by a clamping bracket or magnetic clamping conceivable in which the clamping force is generated magnetically. Particularly simple, however, an anchor bolt is used as a tensioner, which is intended to be fixed in the underlying soil, in particular a foundation, and through which the sheet metal profile is clamped against the ground. Such an anchor bolt is inexpensive and can be easily secured with a dowel in the ground.

In principle, the clamping force of the tensioner can be introduced directly into the elongated profile. But it is better if the clamping force of the tensioner, in particular the

Anchor bolt is applied via a resilient element on the sheet metal profile. Then, a clamping element in addition to the tensioner in addition to a resilient element. As a result, the clamping force can be selectively distributed over a larger area of the elongate profile. It is particularly suitable in this case if the resilient element applies the clamping force in the region of the two height-adjustable feet of the respective end to the sheet-metal profile.

As a result, the clamping force acts almost directly in the area of the height-adjustable feet, so that bending moments in the elongated profile can be almost completely avoided. The tensioning element should then preferably be centered between the two

be provided height adjustable feet of the relevant end of the sheet metal profile.

As a resilient element is particularly a leaf spring, although of course other solutions are conceivable, such as a washer or the like. In addition to the four height-adjustable feet in the four corners of the profile and the two clamping elements of longer sheet metal profiles, of course, further paired height adjustable feet can be attached to the underside of the sheet metal profile over which the sheet metal profile can be stored on the underlying floor and between each pair These feet may be provided a clamping element over which the sheet metal profile is clamped against the underlying soil.

The sheet metal profile used preferably has a cross section which is similar to a lying upwardly open letter "C." Such profiles are easy to manufacture and readily available in this form, but of course the sheet metal profile may also have another suitable cross section.

As a releasable attachment of the cover plate a variety of variants are conceivable, such as bayonet locks or cocking lever locks. However, the cover plates are fastened particularly cost-effectively by means of screws which engage in an associated thread of the sheet-metal profile.

It should be pointed out explicitly at this point that both the elongated sheet metal profile, and the cover plate course does not have to be formed in one piece and that therefore the sheet metal profile may thus include several sub-profiles or the cover plate may comprise a plurality of individual sub-panels.

The walk-in cover can be used in coordinate measuring machines at various points. For example, the cover can be used to cover openings between the floor and the measuring table. Particularly advantageous, however, the opening between the guide beam and the floor is covered, as we will explain in more detail below.

Coordinate measuring machines, on which the walk-in cover is used, have a mechanism for moving the sensor attached thereto in at least two

Coordinate directions, which includes at least one horizontally oriented guide, which is fixed in the region of the bottom and along which a carriage of the mechanism can be moved. Typically, today such coordinate measuring machines are designed as a stand measuring devices, in which the carriage movable along the horizontal guide a vertical

aligned stand is, wherein along the vertically oriented stand another slide (often referred to as a cross slide) is movably mounted and wherein this carriage in turn a horizontally oriented carriage (often referred to as a measuring arm) is movably mounted, at the end of which said sensor is located , The horizontal guide for the vertically oriented stand may be mounted on a guide beam, which in turn is mounted on the underlying floor. The walk-in cover can just as well be used on other coordinate measuring machines. For example, instead of a stand mechanism as well

Portal mechanism can be used, in which a measuring stage spanning portal is movably mounted on both sides of the measuring table in the horizontal direction. Along the traverse of the portal spanning the measuring table, a further slide is then movably guided in a second horizontal direction perpendicular to the first direction of movement, this second slide then movably guiding a third slide in the form of a vertically oriented quill. At the lower end of the sleeve, the sensor is attached. For this purpose, the guides to be provided on two sides of the measuring table can likewise be arranged on guide bars to be arranged laterally from the measuring table, as has already been explained above in connection with the column measuring device and will be explained in more detail below with reference to the figures.

Preferably, the guide bar and the walk-in cover can be mounted on a purpose-built foundation and wherein the foundation in the region of the walk-in cover has an increase.

In addition, a measuring table will be provided in addition, which is also mounted on the underlying foundation. Further advantages of the invention will become apparent from the following description of exemplary embodiments with reference to Figures 1-7 of the accompanying drawings. So the following can be seen from the figures: FIG. 1 shows by way of example a coordinate measuring machine 1 in which a walk-in cover 8 according to the invention is realized,

Figure 2 shows a section through the coordinate measuring machine 1 of Figure 1 along the

Line II-II,

FIG. 3 shows an enlarged detail of FIG. 2, in which the mechanism 23 of FIG

Coordinate measuring device 1 and the mounting of the mechanism 23 can be seen, Figure 4 shows a comparison with Figure 3 again enlarged detail of Figure 2, in which in particular the guide bar 13 and the walk-behind cover 8 according to the invention can be seen,

FIG. 5 shows a perspective view of the accessible cover 8 from above in the unassembled state,

FIG. 6 shows a perspective view of the walk-on cover 8 from below in the unassembled state, FIG. 7 shows a section of the mountable cover according to FIG. 5, in which in particular the tensioning element 24 can be seen.

Figure 1 shows purely by way of example the structure of a coordinate measuring machine 1 with a walk-behind cover 8 according to the invention, which will be described in detail below. As can be seen from Figure 1, the coordinate measuring machine 1 is in this case in the here only schematically and cut as seen to see bottom 5 integrated that the measuring table 6 and additional cover plates 9,10, 11, 31a, 3 lb and 3 lc, which are provided in the region of the mechanism 23 and the measuring table 6 of the coordinate measuring machine 1 with the floor 5 form a plane over which the operator of the coordinate measuring machine 1 without steps can enter the flat measuring table 6.

Before the concrete measures are explained that will allow the flat surface, the function of the coordinate measuring machine 1 will be explained first. For measuring a workpiece 26 shown only schematically here, on the measuring table 6 is applied, the coordinate measuring machine 1 comprises a mechanism 23, via which a sensor 4 only schematically recognizable here in the three coordinate directions x, y and z is movably mounted. The mechanism 23 in this case comprises a first carriage, which is usually referred to as a stand 2, and which is mounted along the measuring table 6 in the horizontal direction displaceably on guides. The guides are not visible in Figure 1 and are located below the cover plates 9,10,11. The position of the stator 2 in this measuring direction (referred to here as the x direction) is determined via a scale, which is likewise not closer, and an associated reading head (not visible here). The scale and the reading head are also below the cover plates 9, 10 and 11. This stand 2 is also driven by a likewise not visible drive, which is also below the cover plates 9, 0 and 1 1 in this measuring direction.

Along the stand 2, another measuring slide, often referred to as a cross slide 27, slidably mounted (here referred to z direction) in the vertical direction, the position of this cross slide 27 also on a scale (not visible here) and an associated reading head (here not visible) is readable. The cross slide 27 is also driven by a drive not shown in detail in the vertical direction (here referred to as z-direction). Along this cross slide 27 in turn is in the horizontal direction (here referred to as y-direction), an elongated carriage, the so-called measuring arm 3, slidably mounted. The horizontal position of this slide is determined by a further scale with associated read head (also not visible here). Also, the measuring arm 3 is driven by a not visible drive. The

Movement direction x of the first carriage (stand 2), the direction of movement z of the second carriage (cross slide 27) and the direction of movement y of the third carriage (measuring arm 3) are perpendicular to the two other directions of movement, so that in each of the coordinate directions x, y and z is a direction of movement.

At the end of the measuring arm 3, a sensor 4 is attached, on the position of the

Workpiece surface of the workpiece 26 can be detected. The here not in detail to be seen sensor 4 is here purely by way of example a tactile sensor, such as a switching probe, which triggers a signal when touching the workpiece with his probe or a measuring probe in which when touching the workpiece 26 with his button the Button is deflected from its rest position and the deflection of the probe is measured. Other sensors, such as optical sensors are just as possible. The coordinate measuring device 1 is also associated with a control and evaluation unit (not shown in greater detail) via which the drives of the coordinate measuring machine are controlled and which reads out the measured values of the scales and reads out the signals of the sensor 4. In addition, the control and evaluation unit includes a measuring computer, with the measurement sequences can be created and the measurement results can be evaluated. Of course, this is just an exemplary description of a control and evaluation unit.

The coordinate measuring machine just described is in total only a device described by way of example only, whose mechanism 23 is referred to as so-called

Stand mechanism is executed. Instead of a stand mechanism, however, a portal mechanism can likewise be used in which a portal spanning the measuring table is movably mounted in the horizontal direction on both sides of the measuring table. Along the traverse of the portal spanning the measuring table, a further slide is then movably guided in a second horizontal direction perpendicular to the first direction of movement, wherein this second slide then movably guides a third slide in the form of a vertically aligned sleeve. At the lower end of the sleeve, the sensor is attached. Like the coordinate measuring machine described above in connection with FIG. 1, each of the measuring carriages is assigned a drive and a scale with a reading head. In connection with FIGS. 2 to 7, the walkable cover 8 of the coordinate measuring machine 1 according to the invention will now be explained.

FIG. 2 shows a section of the coordinate measuring machine 1 from FIG. 1 along the line II-II. As can be seen from this, rests the actual coordinate measuring machine 1, including the measuring table 6, the mechanism 23 and the walkable cover 8 on a specially made for this purpose foundation 7, which is usually made of concrete and in a designated recess of the hall floor. 5 is provided. The foundation here is usually also on a substrate, not shown here, and is thereon, for example, vibration-damping elements that may contain cork layers or plastic layers or spring packs, mounted vibration-damped.

As can be better seen here from Figures 3 and 4, each showing an enlarged section of the representation of Figure 2, the measuring table 6 stored on not provided with reference numerals, height-adjustable feet on the foundation 7 (see. in particular Figure 2). As already described above in connection with FIG. 1, the stand 2 of the mechanism 23 is movably mounted in the horizontal direction indicated by the arrow x. For this purpose, as can be seen particularly well from FIG. 4, a guide bar 13 is mounted on the foundation 7 on a plurality of height-adjustable feet (only the feet 15a and 15b facing in the direction of view are visible in FIG. On the

Guide bar 13 are purely exemplary as linear guides so-called

Ball rail guides provided. These ball rail guides include

Guide rails 16a and 16b, which are mounted on the guide bar 13 and each

Guide rail have two recirculating ball, of which only the front ball recirculating carriage 17a and 7b can be seen in each case. The recirculating ball carriages 17a and 17b are movably supported along the horizontally oriented guide rails 16a and 16b. To the recirculating ball carriages 17a, 17b is fastened (in FIG. 4 only the attachments 28a and 28b belonging to the recirculating ball carriages 17a and 17b are visible) of the foot 14 of the upright 2, so that the upright 2 is a carriage which is in FIG Direction of the ball rail guides (16a, 17a, and 16b, 17b) can be moved.

As explained in detail above, arise through the guide bar 13 openings that must be covered by walk-through covers. In the left-hand area of FIG. 4, a cover plate 11 is provided for this purpose, which covers the area between the measuring table 6 and the guide bar 13. For this purpose, the cover plate 11 is screwed to angle pieces (only the foremost angle piece 21 can be seen in FIG. 4), which in turn are screwed to the measuring table 6. On the guide bar 13, a further cover plate 10 is arranged, which rests directly on the guide bar 13 and is secured thereto by screws. The cover plates 1 1 and 10 are hereby fixed so that between the left edge of the cover plate 10 and the right edge of the cover plate 11, a narrow gap is formed, through which the narrow web of the attachment 28 a and the corresponding narrow web of the underlying, not visible Fastening can reach through, so that located below the cover plates 10 and 11 recirculating ball carriage 17a (and the recirculating ball behind it) on the one hand and located above the cover plates 10 and 11 foot 14 of the stand 2 are in communication. However, this remaining gap is so narrow that thereby the operator of the

Coordinate measuring machine there is no risk of injury. In addition, on the right of the guide bar, the walk-in cover 8 according to the invention can be seen, with which the area facing away from the measuring table between the guide bar 13 and the floor 5 is covered. The exact structure of this walk-through cover 8 will now be explained in more detail with reference to Figures 4 to 7. FIG. 5 shows the walk-in

Cover 8 in the unmounted state from a perspective view from above, Figure 6 shows the walk-in cover in the unmounted state from a perspective view from below. FIG. 7 shows an enlarged detail of the front end of the accessible cover 8 from FIG. 5. As can be seen in particular from FIG. 6, the accessible cover 8 comprises an elongate sheet-metal profile 18, which here is assembled purely by way of example from a plurality of sub-profiles attached to one another. The Blechpro fil 18 has an upper side and a lower side, wherein on the upper side of the sheet metal profile 18 a walk-cover plate 9 is fixed, which also here purely by way of example composed of several partial plates. The

Attachment of the cover plate 9 via screws, of which three are designated by the reference numeral 29 by way of example here.

On the underside of the sheet metal profile 18, a plurality of height-adjustable feet are provided, in Figure 5, only the feet 19a, 19b are designated in the two corners of one end and in Figure 6, only the feet 19c, 19d in the two corners of the other End are designated. Thus, at least in each of the four corners of a height-adjustable foot 19 a, 19 b, 19 c and 19 d attached, over which the sheet metal profile 18 is mounted on the underlying soil, the underlying soil in the present case, a step 12 which in the foundation is provided (see Figure 4). As can be seen from Figures 5 and 6 are in addition to the four height-adjustable feet 19a, 19b, 19c, 19d in the four corners of the profile even more paired height-adjustable feet are attached to the underside of the sheet metal profile 18, via which the metal profile 18 on the underlying Floor 12 can be stored. These height-adjustable feet were not provided with separate reference numbers here.

All height-adjustable feet (19 a, 19 b, 19 c and 19 d and also not provided with reference numerals) each comprise a threaded pin having a plate attached thereto at its lower end and is provided at its upper end with a hexagon socket, so that the threaded pin with an Allen key can be twisted. Of course you can also a slot, a Torx or the like may be provided. In addition, each of the height-adjustable feet includes an internal thread in the sheet metal profile 18, which is either cut directly into the sheet metal profile or can also be performed by a rivet nut or a weld nut. The grub screw is screwed into the thread, wherein the height of the respective foot (19a, 19b, 19c and 19d and also not provided with reference numerals) can be changed by turning the grub screw. By a

Lock nut can be fixed in each case the adjusted height of the foot.

In addition, a plurality of clamping elements 24 are provided, each of which comprises an anchor bolt 20 as a tensioner, via which the sheet metal profile 8 against the underlying soil, ie against the stage to be seen in Figure 4 12 of the foundation 7 can be tensioned. Each anchor bolt 20 is secured by means of a dowel, not shown in detail in a bore in the step 12 of the foundation 7 and is provided at its upper end with a thread on which for tensioning the elongated profile 18 is a self-locking nut

is screwed (see Figure 7). Of course, an additional lock nut can be used to fix the nut.

The clamping force of the anchor bolt 20 is in this case transmitted to the elongated profile via a leaf spring 22, which is easily recognizable in particular in FIG. 7, so that the force is introduced into the profile in the region of two opposite height-adjustable feet 1 a, 19 b, so that virtually no Bending moments are introduced into the profile 18.

As can be seen in particular from FIG. 6, each pair of opposite feet each comprises a corresponding tensioning element 24 with tensioner (anchor bolt 20) and leaf spring 22. However, the reference numerals 24 and 22 only appear once in FIG. 7, as in FIGS. 5 and 6 respectively only the anchor bolts 20 can be seen from the clamping elements 24.

Due to the arrangement shown, the clamping element 24, so the tensioner (here the

Anchor bolt 20) and the leaf spring 22 are achieved several advantages. On the one hand, the anchor bolt 20 is approximately midway between the height-adjustable feet 19 a and 1 b. As a result, the anchor bolt can also be fastened approximately in the middle of the step 20 of the foundation 7, so that neither on the outside nor on the inside of the step 12 a Breakout must be feared. In addition, the tension force generated by the anchor bolt 20 is distributed relatively symmetrically on the height-adjustable feet 19 a and 19 b.

In addition, the elongated profile 18 in the region of the clamping element 24 for the respective tensioner (here the anchor bolt 20) has a larger opening. After the leaf spring 22 is not rigidly connected to the profile 18, but only loosely rests, the profile 18 can be moved back and forth within certain limits transversely to the profile longitudinal direction, as long as the nut 30 of the anchor bolt 20 is not yet tightened to produce the clamping force.

The alignment of the walkable cover 8 is hereby very simple. First, the elongated profile 18 is placed without the walkable cover plate 9 on the step 12 of the foundation 7 and roughly aligned by the height-adjustable feet (19a-19d) are set to the appropriate height and in the horizontal direction approximately the cover plate 9 on the one hand the required Gap to the cover plate 10 complies, so that the attachment piece 28b and the underlying, not visible attachment piece through the gap

fit through. On the other hand, on the side of the floor 5, there should not be too great a gap. Thereafter, the locations for drilling the anchor bolts in Stage 12 will be marked and the holes will be drilled. In a next step, the anchors 20 are anchored in the holes, put on the elongated profile 18, the leaf springs 22 mounted and tightened with the nuts 30 lightly.

Now, a fine adjustment can be made, in which again the

height-adjustable feet (19a-19d) are adjusted to their final height and the horizontal position of the elongate profile 18 are adjusted transversely to its longitudinal direction, before the nuts 30 of the anchor bolt 20 are tightened. Thereafter, the cover plate 9 is fastened via the screws 29. LIST OF REFERENCE NUMBERS

1 coordinate measuring machine

2 stands

3 measuring arm

4 sensor

5 hall floor

6 measuring table

7 foundation

8 walk-in cover

9 cover plate

10 cover plate

11 cover plate

12 level

13 guide bars

14 stand base

15a, 15b height adjustable foot

16a, 16b guide rail

17a, 17b Recirculating ball shoe

18 sheet metal profile

19a-d height adjustable foot

20 anchor bolts

21 angles

22 leaf spring

23 mechanics

24 clamping element

26 workpiece

27 cross slide

28a, 28b attachment

29 screws

30 mother

31a-c cover plate

Claims

Patent claims:

1. Comprehensive walk-in cover (8) for a coordinate measuring machine (1).

a) an elongated sheet metal profile (18) which has a top and a bottom

b) on the underside of the sheet metal profile (18), a height-adjustable foot (19a, 19b, 19c, 19d) is attached at least in each of the four corners, via which the sheet metal profile (18) can be stored on the floor (12) underneath

c) at least one clamping element (24), via which the sheet metal profile (18) can be clamped against the floor (12) underneath

d) a walkable cover plate (9), which is attached to the top of the sheet metal profile via a detachable fastening (29).

2. Walkable cover (8) for a coordinate measuring machine (1) according to claim 1, wherein a clamping element (24) is provided at least at each of the two ends of the sheet metal profile.

3. Walkable cover (8) for a coordinate measuring machine (1) according to claim 1 or claim 2, wherein the clamping element (24) comprises a tensioner, in particular an anchor bolt (20), which is intended for this purpose in the underlying floor, in particular in a foundation ( 7, 12) to be fastened and through which the sheet metal profile (18) is tensioned against the floor.

4. Walkable cover according to claim 3, wherein the clamping force of the tensioner,

in particular the anchor bolt (20) is applied to the sheet metal profile (18) via a resilient element (22).

5. Walk-in cover according to claim 4, wherein the tensioning element (24) is provided in the area of one end of the sheet metal profile (18), in particular centrally between the two height-adjustable feet of this end, and the resilient element (22) the tensioning force in the area of the two feet of the each end is applied to the sheet metal profile (18).

6. Walk-in cover according to claim 4 or 5, wherein the resilient element is a leaf spring.

7. Walk-in cover according to claim 5, wherein in addition to the four height-adjustable feet (19a, 19b, 19c, 19d) in the four corners of the profile and the two

Clamping elements further height-adjustable feet arranged in pairs are attached to the underside of the sheet metal profile (18), via which the sheet metal profile (18) can be stored on the floor (12) underneath and a clamping element (24) is provided between each pair of these feet , via which the sheet metal profile (18) can be tensioned against the floor (12) underneath.

8. Walkable cover according to at least one of the preceding claims, wherein the sheet metal profile (18) has a cross section that is similar to a lying, upwardly opened letter “C”.

9. Walkable cover according to one of the preceding claims, wherein the releasable fastening are screws (29) via which the walkable cover (9) is screwed onto the top of the sheet metal profile.

10. Coordinate measuring machine (1) with a mechanism (23) and one on the mechanism

attached sensor (4), which via the mechanism (23) in at least two

Coordinate directions (x, y, z) is movably mounted, this mechanism (23) comprising at least one horizontally oriented guide (16a, 17a; 16b, 17b) which is attached in the area of the floor and along which a carriage (2). Mechanism (23) can be moved, with at least one accessible cover (8) being provided, which is designed according to at least one of claims 1 to 9.

11. Coordinate measuring machine (1) according to claim 10, wherein the horizontal guide is attached to a guide beam (13), which in turn is attached to the floor below.

12. Coordinate measuring machine according to claim 11, wherein the underlying floor on which the guide beam

(13) and the accessible cover (8) are attached by a Foundation (7) is formed and wherein the foundation has an elevation (12) in the area of the accessible cover.

Coordinate measuring machine according to one of claims 10 to 12, wherein the

Coordinate measuring machine is a stand measuring machine, the carriage of which is movable along the horizontal guide is a vertically aligned stand (2), a further carriage (cross slide 23) being movably mounted along the vertically aligned stand (2) and a horizontally aligned carriage in turn on this carriage (measuring arm 3) is movably mounted, at the end of which the said sensor (4) is located.

14. Coordinate measuring machine according to one of the preceding claims 10 to 13, wherein a measuring table (6) is additionally provided, which is also attached to the underlying foundation (7).