DE102010018493B4 - Coordinate measuring device for determining spatial coordinates on a measurement object and probe for such a coordinate measuring machine - Google Patents

Abstract

Coordinate measuring device (10) for determining spatial coordinates on a measurement object (30), with a probe head (26) which has a probe head sensor system (53) and a body part (38) and a coupling part (40) movable relative to the body part (38) which has a feeler tool (27) and a frame structure (14) designed to move the probe head (26) relative to the measurement object (30), the feeler tool (27) having at least one feeler pin (28) for probing of the measurement object (30) and a rotary plate (74), via which the stylus (28) is coupled to the coupling part (40) in one of several possible rotational angle positions, furthermore with a pin (57) displaceably arranged on the coupling part (40), to which the feeler tool (27) is attached, and a stop (62) arranged on the body part (38) with which the pin (57) can be fixed for movement relative to the coupling part (40), with at least on the body part (38) a rolling projection (68) a is formed on which the turntable (74) by a movement ...

Description

The present invention relates to a coordinate measuring machine for determining spatial coordinates on a measuring object, having a probe head having a probe body and a relative to the body part movable coupling part on which a stylus is arranged, and a frame structure, which is adapted to the Probe to move relative to the measurement object, wherein the stylus has at least one stylus for probing the measurement object and a turntable, via which the stylus is coupled in one of a plurality of possible rotational angular positions of the coupling part.

Furthermore, the invention relates to a probe for such a coordinate measuring machine.

A coordinate measuring machine with a contact tool which can be coupled in different rotational angle positions and a corresponding probe are known, for example, from US Pat US Pat. No. 6,430,828 B1 known.

The known coordinate measuring machine has a probe on which a stylus is arranged with a stylus. The probe is attached to the lower free end of a vertically arranged quill. The quill can be moved in the vertical direction, so that the probe can be moved perpendicular to a measuring table, which serves to receive a measured object. The sleeve is in turn arranged on the cross member of a portal, and it can be moved on the cross member in a first horizontal direction. The portal can be moved together with the quill in a second horizontal direction, so that the probe can be moved in total in three mutually perpendicular directions in space. The maximum travels of the probe along the three axes of motion determines the measuring volume within which spatial coordinates can be determined on a measured object with the aid of the stylus.

To carry out a measurement, the test object is placed on the measuring table. Subsequently, selected measuring points are touched on the measuring object with the free tip of the stylus. From the position of the probe within the measuring volume and from the deflections of the stylus relative to the probe can then determine space coordinates for the touched measuring point. By determining several spatial coordinates at different measuring points, it is possible to determine geometric dimensions and even the object contours of the measured object. A typical field of application for such coordinate measuring machines is the measurement of workpieces for quality control.

Often, the measuring points are located on a test object at a hard to reach for the stylus, z. B. if the depth of a laterally arranged on the measurement object bore should be determined. In order to arrive at such "hidden" measuring points, it is known to use different styli with different styli and / or stylus combinations. For example, there are touch tools in which a stylus is arranged transversely to the spatial z-axis of the coordinate measuring machine, wherein the z-axis here denotes the vertical axis of movement perpendicular to the measuring table. Frequent changes of the stylus and / or stylus combinations are therefore required to carry out a variety of complex and complex measuring tasks. This is disadvantageous because a stylus change costs time and therefore increases the time required to perform the measurement. This is due in particular to a long travel of the probe, since the probe is typically replaced on a magazine arranged outside the measuring volume. As a result, the probe must be moved out of the measuring volume and then return to its position in the measuring volume to perform the change. Thus, the time required for the change is particularly dependent on the size of the coordinate measuring machine. In addition, the flexibility is limited to the available tactile tools, resulting in complex measurements to a variety of tactile tools. If, for example, the depth of a bore is to be determined, which is inclined by 45 ° with respect to the surface of the measurement object, a suitable stylus or a suitable stylus combination is required. Further, the measurement volume is limited by the use of such Taststifte and / or Taststiftkombinationen, since the probe can only be moved so far until it comes into contact with one of the cross member. For very long styli this leads to a correspondingly large restriction.

The aforementioned US Pat. No. 6,430,828 B1 proposes a coordinate measuring machine with a magazine, which has a device for rotating the feeler tool. The rotation takes place about the spatial z-axis by the Tastwer kzeug is stored together with the stylus and / or stylus combination in this device, that is separated from the probe, rotated by the device and then resumed by the probe.

With this device it is achieved that a stylus can be used in different rotated positions. In this way, the number of required styli with styli and / or stylus combinations is reduced because each stylus can be used in different orientations about the z axis. The Measuring time is still long in this coordinate measuring machine, however, since a change of the stylus tool further requires leaving the measuring volume.

Out DE 101 14 126 A1 a probe is known, which makes it possible to turn a probe arranged on the probe directly on the probe. For this purpose, a lowering device is provided on the probe, which first lowers the sensing tool to rotate it. The twisting takes place after lowering by a specially designed electric motor in conjunction with a gear transmission. Following the rotation of the sensing tool is raised by the lowering again.

Advantage here is the time gain, since the stylus must not be moved to a magazine for twisting. The disadvantage is that the probe must be equipped with a dedicated engine and gearbox. This increases the mass of the probe, which adversely affects the acceleration. In addition, the motor changes the temperature of the probe, which is disadvantageous in terms of measurement accuracy. Furthermore, the complexity of the probe increases, resulting in a corresponding overhead in design, production and maintenance result.

EP 0 523 906 A1 describes another probe with a rotatable stylus. The stylus is held magnetically to the probe. A holding magnet for gripping the stylus is connected to a shaft which is rotatable by means of a dedicated motor. To rotate the probe, the holding magnet is advanced together with the shaft to the stylus, so that the stylus is disengaged from its working position. With the help of the motor, the stylus is then rotated. Subsequently, the shaft is retracted to its original position, whereby the holding magnet detaches from the stylus. The probe has the disadvantages already mentioned, resulting from the integration of a special rotary drive in the probe.

DE 10 2007 022 326 A1 discloses a coordinate measuring machine with a passive rotary-pivot mechanism, via which the stylus is spatially adjustable coupled to the probe. The passive rotary swivel mechanism includes a transmission having a drive side and a drive side, the output side coupled to the stylus to displace the stylus relative to the stylus. The drive side has an access to initiate an external drive torque for adjusting the stylus. In the preferred embodiments, the coordinate measuring machine has a linear stop with a longitudinal extent. The input for initiating the drive torque includes a drive wheel that can be engaged with the linear stop to generate the drive torque by movement of the probe relative to the linear stop.

US 6,170,358 B1 discloses an indexing mechanism that allows discrete adjustment of the rotational angular position of a first body relative to a second body. The mechanism includes an intermediate body that is rotatable relative to the first and second bodies. In each case engageable elements in the first body and the intermediate body or an intermediate body and the second body allow the desired indexing.

In an older German (not previously published) patent application of the Applicant with the official file number DE 10 2009 008 722.2 a probe is described with a coupling part to which a stylus is coupled to a turntable and a stylus. The turntable can be brought into a rotational position spaced from the coupling part. In this rotational position of the turntable can be rotated by a frictional engagement on a rolling projection. Advantageously, the turntable is moved by means of measuring force generators, which are arranged to generate a defined contact force in the probe, along the rolling projection and in this way brought into a desired angular position. Subsequently, the turntable must be retracted again into a fixed detent position on the probe.

The probe off DE 10 2009 008 722 A1 allows a rotation of the stylus at any point in the measurement volume, but without an additional motor, as in about DE 101 14 126 A1 is proposed. Therefore, the probe turns off DE 10 2009 008 722 A1 a promising new concept dar. However, it has been shown that the retraction of the turntable in its rest position prepares difficulties. In DE 10 2009 008 722 A1 It is proposed to bring the turntable by a jerky movement of the probe in its rest position. However, this variant can lead to a high bearing wear, because the turntable then stumps on the bearing elements, which fix the turntable in the locked position.

Against this background, it is an object of the present invention to provide a coordinate measuring machine of the type mentioned above, which reduces the number of required Taststiftwechsel and reduces the number of necessary Tastwerkzeuge with corresponding styli and / or Taststiftkombinationen, while keeping the mass and complexity of the probe low become should. Furthermore, the available measuring volume should be used in the most efficient way, and increased bearing wear on coupling points of the probe should be avoided.

According to one aspect of the invention, a coordinate measuring machine and a probe head of the type mentioned are proposed, with a displaceably arranged on the coupling part pin on which the Tastwerkzeug is attached, and arranged on the body part stop, with which the pin for movement relative to the coupling part can be fixed, wherein at least one Abrollvorsprung is formed on the body part, on which the turntable is unrolled by a movement of the coupling part.

The new coordinate measuring machine offers all the advantages of a probe with a rotatable probe. In contrast to the proposals known so far, the new coordinate measuring machine requires no additional motor for rotating the feeler tool. However, such a motor is possible in principle in the context of the present invention. Advantageously, however, the new coordinate measuring machine uses the in DE 10 2009 008 722 A1 described idea. Accordingly, the probe has a Abrollvorsprung on which the stylus can be unrolled to rotate. "Unrolling" is understood here to mean that a traction connection exists between the feeler tool and the roll-off projection, which can be produced in particular by a frictional connection, but also by a positive fit. The turntable acts to rotate the stylus with the rolling projection by the turntable is shifted to the rolling projection until the traction compound is caused by static friction. A suitable (defined) movement of the coupling part and the coupled turntable relative to the Abrollvorsprung then makes it possible to run the turntable - with sufficient static friction substantially slip-free along the Abrollvorsprung along and rotate in this way. The rotation is preferably carried out around the spatial z-axis, ie about a vertical axis of the coordinate measuring machine. Twists about other or other axes are also conceivable. The appropriate movement of the coupling part for rotating the feeler tool results from the geometric shape of the rolling projection. For example, if the rolling projection has a plane rolling plane, the suitable movement is a rectilinear movement of the turntable parallel to the rolling plane. Preferably, however, curved Abrollebenen and in particular an annular rolling plane are provided, which cause the coupling part must follow a correspondingly curved trajectory. Here, "rolling plane" is understood here as the area of the rolling projection, which can be used to form the traction connection.

Regardless of the use of a rolling projection of the probe of the new coordinate measuring machine has a previously not provided stop on which the pin for attaching the turntable directly or indirectly (ie one or more intermediate links) can be blocked against displacement of the coupling part. Since the pin is arranged on the coupling part, it moves as a rule together with the coupling part. The stopper is now designed so that it fixes only the pin and the turntable possibly attached thereto, but not the coupling part. Thus, the stop allows to move the coupling part relative to the pin and the turntable attached thereto. In other words, the stopper is able to hold the pin and possibly mounted on the pin turntable against axial displacement of the coupling part. This can be advantageously used to release the turntable from the coupling part and / or, which is preferred, to approach the coupling part again. The previously proposed jerky movement of the coupling part in the axial direction, which leads to high bearing wear, can be omitted due to the new stop. In the same way, the new stop can also be used in other cases in which a coupling part is to be selectively displaced against a turntable.

It is preferred if the turntable is releasably secured to the pin, as shown later on an embodiment. It is also preferred if the pin is slidably disposed along an axis on the coupling part which is parallel to the axis of rotation of the turntable. It is particularly preferred if the pin can be moved by means of the new stop along the axis of rotation of the turntable against the coupling part.

These embodiments allow a very compact design of the new probe. In particular, the stop can be integrated in these embodiments in a Tastkopfgehäuse surrounding the coupling part and the Tastkopfsensorik. However, it is also possible in principle to arrange the stop outside of such a probe housing.

Preferably, the coupling part and / or the stylus have a detent which allows a secure and reproducible positioning of the stylus on the coupling part. For example, latching balls are conceivable as latching, which are arranged in pairs on the probe and interact with arranged on the scanning tool locking rollers by the locking rollers for locking the Tastwerkzeuges are arranged without play between the locking balls. Particularly advantageous here is a uniformly distributed arrangement of at least three detent ball pairs in conjunction with three correspondingly arranged detent rollers, which form a three-point bearing. A plurality of locking positions can be achieved by providing a corresponding plurality of locking rollers on the tool.

The above object is therefore completely solved.

In a preferred embodiment, the Tastkopfsensorik at least one measuring force generator, which is adapted to cause the movement of the coupling part. In the particularly preferred embodiments, the Tastkopfsensorik includes three measuring power generators, such as in the form of plunger coils and / or piezo actuators, which are adapted to generate a defined contact force (measuring force) in three orthogonal axis directions. These measuring force generators are advantageously used to move the coupling part relative to the body part and in this way to generate a suitable movement in order to unroll the turntable on the rolling projection.

The use of force generators in probes is known per se. Applicant has used such measuring force generators for many years in high-quality probes in order to be able to variably set and regulate the probing force of the probing tool on the workpiece. In this embodiment, a measuring force generator arranged in the probe is advantageously used ("abused") to move the coupling part. It is advantageous that no additional motor is needed, but existing means for moving the coupling part and thus used for rotating the Tastwerkzeuges, which allow a very accurate method of the coupling part and thus of the stylus to the measurement object.

In a particularly preferred variant of this embodiment, the at least one measuring force generator includes an actuator which is able to move the coupling part approximately parallel to the axis of rotation of the turntable.

In this variant, the axial displacement of the coupling part is effected relative to the turntable by means of a measuring force generator. It is particularly advantageous if a first and a second measuring force generator allow a movement of the coupling part in two orthogonal directions, which are transverse to the rotational axis of the turntable (typically referred to as x and y direction). These two measuring force generators can be used advantageously to produce the appropriate movement of the coupling part relative to the rolling projection. A third measuring force generator allows a movement of the coupling part parallel to the axis of rotation (z-direction). The third measuring force generator is advantageously used together with the new stop to approximate the coupling part to the turntable, after a rotary movement of the turntable with the other two measuring force generators and the rolling projection was generated. When the coupling part has been brought close enough to the turntable with the aid of the third measuring force generator and the new stop, an electromagnet can be advantageously activated which brings the turntable into its final stop position. The stop and the third measuring force generator serve in this case to reduce the air gap between the electromagnet and the turntable with a defined movement so far that the turntable can be fixed without major bearing damage to the coupling part.

In a further preferred embodiment, the rolling projection is a cylinder arranged largely concentrically to the turntable.

In this embodiment, the rolling projection is a tube-like element which extends in the radial direction around the turntable and at least largely surrounds it. It is possible that the cylinder does not completely surround the turntable, but for example over a wrap angle of 270 °. It is advantageous if the inner shell of the cylinder, ie the rolling plane, has a radius which is greater than the radius of the turntable. This ensures that the turntable only cooperates with the rolling plane, if desired. In addition, it follows that the turntable can be rotated freely. In particular, in the case of a circular design of the turntable, it is possible to rotate it continuously by a circular movement of the coupling part around the center of a circular tube. Thus, turntable and Abrollvorsprung form a friction gear, by which the turntable is rotated according to its translation. A settling and subsequent reorientation of the turntable at the unwinding plane, as would be necessary in a non-continuous rolling plane, is thereby avoided.

In a further embodiment, the coordinate measuring machine has at least one traction element, in particular a rubber-like ring, which is arranged between the turntable and the roll-off projection.

In this embodiment, the traction element improves the traction connection between the turntable and the Abrollvorsprung Turning the turntable and it also serves as a stop when applying the turntable on Abrollvorsprung. In particular, materials which generate high friction, such as rubber (natural rubber or synthetic) or rubber-like materials, are particularly advantageous. In one embodiment, the traction element may be an O-ring made of a rubber-like material. In another embodiment, the traction element is a ring-shaped closed flat belt. These embodiments offer the advantage that the traction element surrounds the turntable concentrically in the circumferential direction and in particular can be arranged directly on the turntable edge, whereby the turntable is protected all around against shocks and the continuous movement is steadily supported. A flat belt has proved to be advantageous because of the larger compared to the O-ring contact surface.

In a further embodiment, the probe with the probe tool forms an alignment detection device for detecting the orientation of the turntable in the direction of rotation.

In this embodiment, the orientation detection device allows that upon rotation of the turntable or when changing the feeler tool can be determined which alignment it has. This makes it easier to prevent collisions with elements outside the measurement volume. Furthermore, the alignment detection device allows control over a reproducible engagement of the stylus in the detent of the probe by verifying the correct position.

In a further embodiment, it is provided that the orientation detection device has a plurality of alignment determination elements, in particular electrical identification circuits, which are each associated with a specific orientation of the touch tool, and has at least one sensor which cooperates with the alignment determination elements.

In this embodiment, the orientation detecting device assigns each orientation of the stylus to a separate orientation determining element, whereby each orientation can be uniquely recognized. The alignment determination elements are preferably arranged on the stylus, whereby it is possible to equip each stylus individually with alignment designation elements. In this way, different probing tools may have a different number of orientation determining elements that meet the requirements of the respective Tastwerkzeuges. Thus, with a small number of different orientations needed, orientation determining elements can be saved. Thus, in addition mass on the stylus and components for the alignment determination elements can be saved.

The sensor is preferably arranged on the probe head, in particular on the coupling part, so that during a measuring operation of the coordinate measuring machine the orientation and the correct locking of the probe tool can always be checked.

The use of identification circuits as alignment destination elements means that additional information such as, for example, the type of touch tool or geometric data of the touch tool can be stored in the identification circuits. The identification circuits are preferably designed as integrated circuits.

In a further embodiment, the orientation determining elements are arranged angularly offset from each other in the direction of rotation of the turntable.

In this embodiment, the alignment determining elements are preferably evenly angularly offset on an imaginary circular line around the center of the rotational movement of the turntable during a rotation. Thus, the correct orientation determining elements are automatically guided to the sensor in accordance with the orientation of the turntable, when it is arranged with respect to the alignment determining elements with a fixed position.

In a further embodiment, the alignment determination elements each have at least two contacts, which are arranged radially in succession to the direction of rotation of the turntable.

In this embodiment, it is achieved that only the correct contact is guided to the associated sensor during rotation. This is particularly advantageous in an electrical connection, for example in an embodiment of the orientation determination elements as identification circuits, since only a correct electrical connection with the orientation determination elements is possible. In particular, it is provided to use two contacts associated with the sensors in the form of mating contacts when using two contacts.

The turntable and its current orientation are thus always visible, even after switching on the coordinate measuring machine, ie after a de-energized state. Due to this information, for example, collisions when changing the stylus in the magazine can be prevented.

In a further embodiment, a closure on the turntable is provided, which cooperates with the centering pin. The closure allows a secure coupling between the stylus and the coupling part. In a preferred embodiment, a circumferentially arranged on the centering pin groove is provided, which forms a Hintergriffsstufe, which is located when coupling the turntable to the centering within the turntable. For safe coupling, the turntable on at least one of the rear handle stage associated locking element which engages in the groove and holds the turntable due to the Hintergriffsstufe. This coupling additionally requires a device for separating the turntable from the centering pin in order to be able to bring about, for example, a change of the feeler tool. In this way, an accidental ejection of the touch tool is prevented. The groove preferably has a beveled wall, whereby a secure fit, a slight engagement and a simple release can be achieved. Furthermore, the use of a corresponding wall makes it possible, in the event of a collision, for the feeler tool to be released from the centering pin, so that damage to the feeler tool and / or to the probe head is reduced or prevented.

In a further embodiment, the movable centering pin has at least one latching position and at least one rotational position.

The detent position is the position in which the turntable is rotationally fixed to the coupling part. In the rotational position, it is possible to rotate the turntable relative to the coupling part. This is achieved in particular in that the centering pin is pushed axially to reach the rotational position of the coupling part and in this way the turntable wins a distance to the coupling part. In the rotational position of the turntable can then be freely, so without disturbing influence of the coupling part or, for example, the detent, twisted. To reach the locking position of the centering pin is withdrawn by means of the new stop again in the coupling part, so that the turntable is ultimately applied flat against the coupling part and receives a rotationally fixed position. The moving out of the centering pin can be done in particular in the direction of the z-axis by gravity, whereas the moving in takes place advantageously with the new stop.

In a further embodiment, the centering pin has at least one cone-shaped portion which cooperates with at least one bearing element.

In this embodiment, it is achieved that the centering pin can either be mounted in the bearing element or moved out of the bearing element. During a return movement, the centering pin is then correctly aligned immediately upon contact with the bearing element and stored safely.

In a further embodiment it is provided that the cone-shaped portion is mounted without play in the rotational position by the bearing element and is arranged in the locking position at a distance from the bearing element.

In this embodiment, the play-free storage in the rotational position allows a highly accurate rotation of the feeler tool. At the same time it is achieved that the feeler can be pressed against the Abrollvorsprung with a defined pressure, so that there is always a constant traction connection between Abrollvorsprung and turntable during the rotation. This is particularly advantageous if styli and / or stylus combinations are used, which have a large eccentric mass, since they can also be aligned exactly in a twisting. The arrangement of the cone-shaped portion with a distance to the bearing element in the detent position causes the turntable can be precisely applied to the coupling part and no opposing forces and mechanical stresses are generated by the centering pin. This is especially true in connection with a detent, as already described above.

In a further embodiment, the coupling part between the stop and the turntable is arranged. In this embodiment, the turntable and the stop are on different sides of the coupling part. The stop is in "negative" z-direction to the turntable and is advantageously integrated in a probe housing, which also umhaust the coupling part and the probe head. The design allows a very compact and protected design.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. Show it:

1 a coordinate measuring machine according to an embodiment of the present invention,

2 a simplified representation of a probe with a Tastkopfsensorik and a measuring force generator,

3 a preferred embodiment of the probe for the coordinate measuring machine 1 in a view of the interface,

4 the probe off 3 in a sectional view along the line III-III,

5 a preferred embodiment of a Tastwerkzeuges for the coordinate measuring machine 1 in a plan view of the changeover interface,

6 another embodiment of a stylus for the coordinate measuring machine 1 in a plan view of the changeover interface,

7 a simplified representation of a probe during rotation of the stylus, and

8th - 10 the coupling part of the probe 3 in different operating positions in a sectional view.

In 1 is an embodiment of the new coordinate measuring machine in its entirety by the reference numeral 10 designated. The coordinate measuring machine 10 owns a base here 12 on which a frame construction 14 is arranged displaceably in the longitudinal direction. The direction of movement of the frame structure 14 relative to the base 12 is commonly referred to as the y-axis. At the upper cross member of the frame structure 14 is a sled 16 arranged, which is displaceable in the transverse direction. The transverse direction is commonly referred to as the x-axis. The sled 16 wears a quill 18 in the z-direction, perpendicular to the base 12 , can be moved. With the reference numbers 20 . 22 . 24 are measuring devices designated by which the position of the frame structure 14 , the sled 16 and the quill 18 can be determined. Typically, these are the measuring devices 20 . 22 . 24 around glass scales, which are read with the help of suitable sensors.

At the lower free end of the quill 18 is a probe 26 arranged, which is a tactile tool 27 holds. The touch tool 27 here has three styli 28 on, each at its free ends a Tastkugel 29 have. This serves to create a measuring point on a measuring object 30 to touch. With the help of measuring equipment 20 . 22 . 24 can be the position of the probe 26 within the measuring volume when touching the measuring point. Depending on this, one can then determine the spatial coordinates of the touched measuring point.

With the reference number 32 is an evaluation and control unit called via lines 34 and 36 is connected to the drives and sensors on the frame structure. The control unit 32 Serves the motor drives for the movements of the probe 26 to drive along the three coordinate axes x, y and z. In addition, the evaluation and control unit reads 32 here the measured values from the measuring devices 20 . 22 . 24 and determines depending on and depending on the deflections of at least one of the styli 28 the current spatial coordinates of the measuring point and optionally further geometric variables of the measured object 30 ,

2 shows on the basis of a highly simplified, schematic representation of the basic operation of the probe 26 , The probe 26 owns a body part 38 and a coupling part 40 that have leaf springs 42 and 44 connected to each other. The leaf springs 42 . 44 form a spring parallelogram, which is a movement of the coupling part 40 in the direction of the arrow 46 (and back in the direction of the arrow 46 ' ). This can be the touch tool 27 with the styli 28 be deflected by a distance D from its rest position. With the reference numbers 28 ' and 29 ' is one of the styli 28 with the probe ball 29 shown in the deflected position.

The deflection of the stylus 27 relative to the body part 38 can be the consequence of a probing of the measurement object 30 be at a measuring point. Advantageously, the deflection of the feeler tool 27 taken into account when determining the spatial coordinates. In addition, the deflection of the feeler tool 27 in the preferred embodiments by means of a measuring force generator 56 are generated, as explained in more detail below. At the fuselage part 38 and on the moving part 40 is each a thigh 48 . 50 arranged. The thigh 48 . 50 stand here parallel to the leaf springs 42 . 44 , Between the thighs 48 . 50 here are a detector 52 (here with a scale 54 shown) and the measuring force generator 56 arranged. The detector 52 here has a measuring coil 53 in the form of a plunger coil. As a detector 52 Alternatively or additionally, a Hall sensor, a piezoresistive sensor or another sensor are conceivable, with the aid of which the spatial deflection of the feeler tool 27 relative to the body part 38 (more precisely, the deflection of the spring parallelogram, that of the leaf springs 42 . 44 is formed) can be determined. The measuring force generator 56 is also designed here as a plunger coil. With their help, the two thighs 42 and 50 be pulled or pushed apart by a core 59 is attracted or repelled.

In the simplistic representation in 2 allows the probe 26 only one Deflection of the touch tool 27 in the direction of the arrow 46 , However, the skilled person is aware that such a probe 26 typically allows a corresponding deflection in two other, orthogonal spatial directions. However, the invention is not limited to this particular probe and may be practiced with other probes having a body portion 38 and a relatively movable coupling part 40 have.

3 shows a preferred embodiment of the probe 26 out 1 in a view from below. The body part 38 holds the coupling part 40 which is movable on the body part 38 is attached. The coupling part 40 has a pin 57 on, in the coupling part 40 with a direction of movement perpendicular to the direction of movement 46 is guided (is based 8th to 10 explained in more detail). In the edge region of the coupling part 40 are pairwise detent balls 58 arranged. The paired arrangement is chosen so that the detent ball pairs each have the same radial distance to the centering pin 57 have. Furthermore, the paired detent balls are 58 evenly to each other on the circumference of the coupling part 40 distributed. The coupling part 40 also has a magnet 60 , here in the form of an annular electromagnet. The electromagnet is concentric with the centering pin 57 on the coupling part 40 arranged. In addition, has the coupling part 40 a sensor 64 , here with two contacts 66 , At the fuselage 38 is a roll-over projection 68 in the form of a circular tube with an inner jacket 72 educated.

4 shows a simplified section of the probe 26 of the 3 along a section line III-III. The roll-off projection 68 Here is the circular tube with the inner jacket 72 , concentric to the pin 57 extends. As in the explanation of 2 has been mentioned is the coupling part 40 over a number of spring elements 42 movable on the body part 38 stored. With the help of measuring force generators 56 can change the position of the coupling part 40 be changed relative to the body part. In addition, a movement of the coupling part 40 relative to the pin 57 to allow, in the preferred embodiment, a stop 62 provided here at the fuselage part 38 is formed or at least rigidly coupled with this. The stop 62 works with a plate 63 together, the top of the pin 57 is arranged. In 4 The plate is above the stop 62 , The top of the pin 57 stands over the stop 62 upwards. When the coupling part 40 with the help of the measuring force generator 56 is pressed down, the pin follows 57 this movement until the plate 63 from above against the stop 62 encounters. From this position, the pin is 57 blocked against further downward movement. The coupling part 40 In contrast, with the help of the measuring force generator 56 continue to be pressed down. From the moment in which the pin 57 over the plate 63 at the stop 62 is blocked, the measuring force generator moves only the coupling part 40 down, not the pin anymore 57 , In other words, the measuring force generator pushes 56 the coupling part 40 down relative to the pin. Because the pin 57 is designed with its lower free end to hold a stylus (is based on the 8th to 10 explained in more detail), one can with the help of the measuring force generator 56 and the stop 62 the distance between the coupling part 40 and the touch tool 27 vary and in particular decrease. This is advantageously used in embodiments of the new coordinate measuring machine to the coupling part 40 "Gentle" to the touch tool 27 move on and then with the magnet 60 to fix.

5 shows a preferred embodiment of the Tastwerkzeuges 27 in a top view. The touch tool 27 has a turntable 74 , which is circular here. In the circumferential direction around the turntable 74 is a traction element 76 , here exemplified in the form of an O-ring arranged. Instead of an O-ring in other embodiments, a flat belt made of a rubber-elastic material is placed concentrically on the outer edge of the turntable. The turntable 74 has several locking rollers 80 that are radial to the turntable 74 are rotatably arranged. The detent rolls 80 are on the circumference of the turntable 74 distributed at regular intervals. Radially inward to each locking roller 80 are two contacts 82 arranged. The contacts 82 lie here in the radial direction of the turntable 74 one behind the other, resulting in a circumferentially distributed arrangement of contact pairs. Each pair is part of an alignment destination 84 (see also 8th ). For the sake of clarity, only one of the orientation design elements became 84 shown in dashed lines. The alignment features 84 are formed here with electrical identification circuits in the form of integrated circuits. Each identification circuit represents a clear information about what position it is on the turntable 74 located. Based on this information, the position of the turntable 74 be recognized in the circumferential direction. Furthermore, at least one identification circuit contains information that the identity of the Tastwerkzeuges 27 represents. At the center of the turntable 74 is a recording 90 provided in the form of a circular recess. Within the recording 90 are two locking elements 92 arranged.

The touch tool 27 is here on the probe 26 out 3 and 4 used. To this Purpose is the recording 90 formed so that it the lower free end of the pin 57 can record and by means of the locking elements 92 can lock.

The contacts 82 are aligned so that they are paired with the contacts 66 of the probe 26 ( 3 ) can work together. This means that when placing the stylus 27 on the probe 26 an electrical contact between the contacts 66 and two contacts 82 will be produced. In this way it is possible to read the information from exactly one identification circuit.

The touch tool 27 here wears the three styli 28 corresponding 1 , The styli 28 are below the turntable 74 arranged. The training of the Tastwerkzeuges is not on the in 5 limited manner shown. It is possible to use styli of different lengths and / or geometries. The number of styli used is variable.

6 shows an alternative touch tool 27 , Compared to the stylus of 5 are further detent rollers 80 and related contacts 82 and alignment features 84 on the turntable 74 arranged.

When using the styli tools 27 out 5 and 6 on the probe 26 of the 3 and 4 form the detent balls 58 with the locking rollers 80 a detent. The detent creates a secure and reproducible seat as soon as the detent rollers 80 between the paired detent balls 58 engage. Due to the design of the coupling part 40 in each case three locking rollers 80 of the touch tool 27 each of a pair of detent balls 58 in the circumferential direction of the turntable 74 fixed, resulting in a three-point bearing. The contacts 82 the alignment determination elements 84 are arranged such that upon correct latching, they read out the alignment determining elements 84 enable.

7 shows the probe 26 out 3 or 4 as well as the turntable 74 out 5 in a simplified representation from below. The probe 26 is here only with the outer contour of the fuselage 38 and the roll-over protrusion 68 shown. The turntable 74 is here with a recording block 94 for styli 28 and the traction element 76 shown. To move the turntable 74 relative to the probe here are the measuring force generators 56 used the measuring forces in the direction of the double arrows 96 and 97 produce. The directions 96 and 97 are orthogonal to each other and corresponding to the directions of movement x and y of the coordinate measuring machine 10 , With the help of these measuring forces, it is possible to turn the turntable 74 within the roll-over protrusion 68 to move. In the position shown is the turntable 74 with the traction element 76 on the inner jacket 72 and forms a frictional connection on the rolling projection 68 ,

By a circular movement (arrow 100 ) of the turntable 74 , here concentric to the rolling projection 68 is done, turning the turntable 74 in the direction of the arrow 102 reached. The circular movement is controlled by appropriate control of the measuring force generators along the arrows 96 and 97 generated. The movement 102 is carried out until the stylus reaches the desired rotational position. Subsequently, the turntable 74 be moved back to its central rest position. Preferably, the rest position is centered to Abrollvorsprung 68 , Due to the different radii of the rolling projection and the traction element 76 These elements form a friction gear 104 , which, with appropriate dimensioning, the rotational speed of the turntable 74 certainly.

8th shows a sectional view of the coupling part 40 out 4 and the turntable 74 out 5 in a first operating position. For the sake of simplicity, the pin 57 not shown here in its entirety. In particular, the upper end with the plate is missing here 63 that at the stop 62 ( 4 ) can be retained to the coupling part 40 relative to the pin 57 to move.

The coupling part 40 indicates the ring magnet 60 on top of a holding device 106 concentrically surrounds. The holding device 106 owns here two bearing elements 108 in the form of ball bearings, which are annular and concentric with the centering pin 57 are arranged.

Inside the holding device 106 is the centering pin 57 arranged, which two cone-shaped sections 112 and 114 has. In the illustrated position of the centering pin 57 lie the cone-shaped sections 112 . 114 free of play on the bearing elements 108 at. That within the coupling part 40 lying end of the centering 57 forms a holding projection 116 , the centering pin 57 within the holding device 106 secures against high tensile forces. The outside of the coupling part 40 lying section 118 is formed substantially conical. The section 118 has a groove 120 on, which in the circumferential direction of the centering pin 57 is trained. The to the coupling part 40 pointing wall 122 the groove 120 forms another cone-shaped section 124 , which is opposite to the cone-shaped sections 112 and 114 is oriented. The free end of the centering pin 57 forms another cone-shaped section 126 whose orientation is the orientation of the cone-shaped sections 112 . 114 equivalent. Furthermore, here are one of the locking balls 58 as well as the contacts 66 to see.

The turntable 74 carries the traction element 76 , On the coupling part 40 facing side of the turntable 74 are two detent rollers 80 and two alignment features 84 shown. The recording 90 is formed substantially conical, so that a secure fit of the centering 57 within the recording 90 and automatic centering are ensured. Within the recording 90 is a cylindrical recess 128 , inside the locking elements 92 can be moved. The turntable 74 holds the recording block 94 , styli 28 are not shown for reasons of clarity.

9 shows the coupling part 40 , the centering pin 57 and the turntable 74 in a second operating position. In contrast to 8th is the turntable 74 here at the centering pin 57 attached. For this purpose, the centering pin 57 in the recording 90 plugged in, leaving the locking elements 92 in the groove 120 intervention. Thus, the cone-shaped portion forms 124 a system for the locking elements 92 , and the groove 120 forms with the locking elements 92 a closure.

In the position of the turntable shown here 74 remains a distance between the detent ball 58 and the nearest detent roller 80 , Therefore, it is possible the turntable 74 around the centering pin 57 to turn around. Here are the cone-shaped sections 112 and 114 free of play on the bearing elements 108 at. Thus, the centering pin is located 57 in a rotational position 134 turning the turntable 74 allows.

By an axial movement of the coupling part 40 in the direction of the movement arrows 136 (ie in the longitudinal direction of the pin and thus parallel to the axis of rotation of the turntable 74 ) you can the turntable 74 from the in 9 shown, spaced position in one to the coupling part 40 bring close position. The coupling part becomes advantageous 40 with the help of the measuring force generator 56 so far down from the fuselage 38 pushed away that plate 57 at the top of the pin 57 against the attack 62 drives and its position relative to the fuselage 38 from then on not changed. The coupling part 40 is done with the help of the measuring force generator 56 on the other hand pressed further down and thus moves on the turntable 74 at the bottom of the pin 57 to.

10 shows the coupling part 40 , the centering pin 57 and the turntable 74 out 8th and 9 in a corresponding third operating position. Besides, now is the electromagnet 60 magnetized to the turntable 74 in the coupling part 40 to fix close position. In this near position, the detent balls act 58 with the nearest detent roller 80 together, causing a click of the turntable 74 effected in a defined position.

Because of the pin 57 relative to the coupling part 40 pushed up are the cone-shaped sections 112 and 114 now with a distance 138 to the bearing elements 108 arranged. Because of these distances 138 owns the centering pin 57 now within the fixture 106 Game. In this way it is prevented by the centering pin 57 Counter forces are generated, which are against the orientation of the turntable 74 act through the detent. Thus, the centering pin is located 57 in a rest position 140 , In this is a reproducible catch with high-precision position of the turntable 74 to the coupling part 40 reached.

To release the turntable 74 from the centering pin 57 need the locking elements 92 out of the groove 120 be moved out. For this purpose, a device, not shown here, is provided, which is accessible from the outside and so a manual as well as an automated movement of the locking elements 92 allows.

In further embodiments, it is conceivable to virtually refine an angle division for the possible positions of the styli. For this purpose, a suitable number of equidistant detent positions is selected. Further, a plurality of - preferably identically designed - Taststifte are arranged radially to a common center on the probe. An angular pitch between the styli (circumferentially about the midpoint) is chosen so that the angular pitch of the styli differs from the angular pitch of the detent and does not multiply thereof. This ensures that the styli can be arranged at a variety of angular positions. Since the angular positions in the circumferential direction, that is to say in the direction of rotation of the probe, are not arranged directly one after the other, it is advantageous if the corresponding probe positions in conjunction with the respective angular positions of the probe pins are communicated to a control device. Thus, it is possible for a user to be provided with a refined angle division and, by selecting the corresponding angle division, the probe head is automatically rotated into the correct position.

In one embodiment, it is provided that the probe 24 has equidistant detent positions. These are then arranged at a 15 ° angle to each other about a common center. Using three equidistant styli results in an angular pitch of 120 ° for the styli to each other. Due to the same configuration of the Taststifte and the ratio between the angular pitch of the detent positions and the angular pitch of Taststifte results in a virtual angular pitch of 5 °. Overall, therefore, a required stylus can be arranged not only in the original 24 positions, but the three styli together can be arranged in 72 different positions.

The basic principle can be done with different divisions. Preferred examples are: three equidistant detent positions in conjunction with four equidistant styli, resulting in a virtual 30 ° pitch; Three detent positions in conjunction with five styli, resulting in a virtual 24 ° pitch and six detent positions in conjunction with a star key, resulting in a 15 ° division. Due to the virtual detent the number of required styli is minimized and the calibration effort is minimized. Overall, thus even greater flexibility in the use of the corresponding probe is possible.

Claims (13)

Coordinate measuring machine ( 10 ) for determining spatial coordinates on a measurement object ( 30 ), with a probe sensor system ( 53 ) probe ( 26 ), which is a body part ( 38 ) and a relative to the body part ( 38 ) movable coupling part ( 40 ), on which a touch tool ( 27 ), and a frame structure ( 14 ), which is adapted to the probe ( 26 ) relative to the measurement object ( 30 ), whereby the stylus ( 27 ) at least one stylus ( 28 ) for touching the measurement object ( 30 ) and a turntable ( 74 ), over which the stylus ( 28 ) in one of a plurality of possible angular positions of the coupling part ( 40 ) is coupled, further with a on the coupling part ( 40 ) displaceably arranged pin ( 57 ) on which the touch tool ( 27 ), and one on the body part ( 38 ) arranged stop ( 62 ), with which the pin ( 57 ) for movement relative to the coupling part ( 40 ) is fixable, wherein at the fuselage part ( 38 ) at least one roll-off projection ( 68 ) is formed, on which the turntable ( 74 ) by a movement of the coupling part ( 40 ) is unrolled. Coordinate measuring machine ( 10 ) according to claim 1, characterized in that the probe sensor ( 53 ) at least one measuring force generator ( 56 ), which is adapted to the movement of the coupling part ( 40 ) to effect. Coordinate measuring machine ( 10 ) according to claim 1 or 2, characterized in that the roll-off projection ( 68 ) is a tubular element which extends in the radial direction about the rotary divider ( 74 ) extends around and at least largely surrounds it. Coordinate measuring machine ( 10 ) according to one of claims 1 to 3, characterized by at least one traction element ( 76 ), in particular a rubber-like ring ( 76 ) between the turntable ( 74 ) and the roll-off projection ( 68 ) is arranged. Coordinate measuring machine ( 10 ) according to one of the preceding claims, characterized in that the probe head ( 26 ) with the stylus ( 27 ) an alignment detection device ( 84 ) for detecting the orientation of the turntable ( 74 ) in the direction of rotation forms. Coordinate measuring machine ( 10 ) according to claim 5, characterized in that the orientation detecting device ( 84 ) multiple alignment features ( 84 ), in particular electrical identification circuits ( 84 ), each having a particular orientation of the Tastwerkzeuges ( 27 ) and at least one sensor ( 64 ) associated with the alignment features ( 84 ) cooperates. Coordinate measuring machine ( 10 ) according to claim 6, characterized in that the orientation determining elements ( 84 ) in the direction of rotation of the turntable ( 74 ) are arranged angularly offset from one another. Coordinate measuring machine ( 10 ) according to claim 6 or 7, characterized in that the orientation determining elements ( 84 ) at least two contacts ( 82 ), which are radial to the direction of rotation of the turntable ( 74 ) are arranged consecutively. Coordinate measuring machine ( 10 ) according to one of the preceding claims, characterized in that the pin ( 57 ) at least one detent position ( 140 ) and at least one rotational position ( 134 ) having. Coordinate measuring machine ( 10 ) according to one of the preceding claims, characterized in that the pin ( 57 ) at least one cone-shaped section ( 112 . 114 ) having at least one bearing element ( 108 ) cooperates. Coordinate measuring machine ( 10 ) according to claim 9 and 10, characterized in that the cone-shaped portion ( 112 . 114 ) in the rotational position ( 134 ) by the bearing element ( 108 ) is mounted without play and in the latching position ( 140 ) with a distance ( 138 ) to the bearing element ( 108 ) is arranged. Coordinate measuring machine ( 10 ) according to any one of the preceding claims, characterized characterized in that the coupling part ( 40 ) between the stop and the turntable ( 74 ) is arranged. Probe for a coordinate measuring machine ( 10 ) for determining spatial coordinates on a measurement object ( 30 ), with a body part ( 38 ) and one relative to the body part ( 38 ) movable coupling part ( 40 ), with a probe sensor ( 53 ), and with one with the coupling part ( 40 ) couplable stylus ( 27 ), which has a stylus ( 28 ) for touching the measurement object ( 30 ) and a turntable ( 74 ), over which the stylus ( 28 ) in one of a plurality of possible angular positions of the coupling part ( 40 ) is coupled, further with a on the coupling part ( 40 ) displaceably arranged pin ( 57 ) on which the touch tool ( 27 ), and one on the body part ( 38 ) arranged stop, with which the pin ( 57 ) for movement relative to the coupling part ( 40 ) is fixable, wherein at the fuselage part ( 38 ) at least one roll-off projection ( 68 ) is formed, on which the turntable ( 74 ) by a movement of the coupling part ( 40 ) is unrolled.

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