DE102013107948B4 - Coordinate measuring device and method for measuring workpieces - Google Patents

Abstract

Coordinate measuring device for measuring workpieces, having a measuring table (16) for receiving a workpiece, with a sensor carrier (20) which is movable along at least one movement axis (X, Y, Z) relative to the measuring table (16), wherein the sensor carrier (20 ) with an optical sensor (22) for measuring workpieces, wherein the measuring table (16) has an at least partially optically transparent workpiece support (24), and with a lighting unit (36) for illuminating the workpiece, the at least one movable transmitted light source ( 38), wherein the at least one transmitted light source (38) for movement entrainment with the movable sensor carrier (20) is coupled, characterized by a coupling unit (50) which is adapted to the at least one transmitted light source (38) selectively from the movable sensor carrier (20 ), wherein the at least one transmitted light source (38) and the movable sensor carrier (20) einkopp a selectively wherein the traction means (48) has a driver (74) which is fixed to the traction means (48), and wherein the coupling unit (50) comprises a gripper (72) with at least one gripper (74) ) coupled gripping element (88; 96) which is displaceable between a driving configuration and a release configuration.

Description

The present invention relates to a coordinate measuring machine for measuring workpieces, having a measuring table for receiving a workpiece, with a sensor carrier which is movable along at least one movement axis relative to the measuring table, wherein the sensor carrier can be coupled to an optical sensor for measuring workpieces, wherein the Measuring table has an at least partially optically transmissive workpiece support, and with a lighting unit for illuminating the workpiece, which has at least one movable transmitted light source, wherein the at least one transmitted light source for Bewegungsmitnahme with the movable sensor carrier can be coupled.

The invention further relates to a corresponding method for measuring workpieces.

A coordinate measuring machine of the aforementioned type is approximately from the DE 201 16 124 U1 as well as the US 6,518,996 B1 known.

From the DE 20 2004 003 893 U1 a coordinate measuring machine is known which comprises a portal with side supports and a cross member extending therefrom and a slidable carriage along the cross member, wherein the carriage is an optically or optically tactile working sensor, the coordinate measuring machine further comprises an optically transmissive measuring table for an object to be measured and a base plate which is spaced from the measuring table, wherein between the measuring table and the base plate, a transmitted light source is arranged, which is interspersed regardless of the position of the sensor from the optical axis, and wherein the transmitted light source is a light band extending from the side supports ,

From the DD 68 979 A5 a device is known for determining the cumulative pitch error in the pitch test of straight or helical gears and grooved parts, wherein an individual measurement error representing electrical measurement is optionally given after amplification on a display device, the device further comprising a measuring carriage which moves by a cable is, wherein the cable comprises a cable which is guided over a pulley, wherein rotations of the pulley are transferable via an electromagnetic clutch to an axle.

Coordinate measuring machines are well known in the art. They serve, for example, to check workpieces within the scope of a quality assurance or to determine the geometry or further parameters of a workpiece in the context of a so-called "reverse engineering". In addition, a variety of other applications are conceivable.

When it comes to research, development, but also one-off production or series production of products, metrology is of great importance, especially in terms of quality assurance. Thus, it may already be necessary in early phases of a product development to detect the shape of sample parts in order to ensure, for example, that functional dimensions, shape tolerances, positional tolerances, surface properties or the like are within tolerance ranges determined by the design. The determination or detection of such measures or, if applicable, their dispersion allows feedback with the product development process. Thus, any changes or adjustments that may be required to improve the maturity of a product may be derived from the characteristics or behavior of the sample parts.

In addition to development-accompanying measurement tasks, metrology is also a frequently indispensable aid and quality control element in the planning, set-up and implementation of series production.

For measuring the geometry of a test object, in general of workpieces, but also for detecting further features such as surface properties, positional tolerances, shape tolerances and the like, the coordinate measuring technique is particularly suitable. In this case, a measurement object is scanned in a coordinate system, which may be predetermined by the design of a used measuring device. It can be done a detection of space points, space curves or space paths and surface elements. The detected values can be understood as an actual image of the workpiece or measurement object in the coordinate space.

As a rule, a coordinate measuring machine has a structure which allows a sensor to travel along a plurality of spatial axes within a specific coordinate space and optionally also to be pivoted about at least one spatial axis. The required drive can always be done manually or motorized. A large number of coordinate measuring machines are similar in their basic structure to, for example, CNC multi-axis milling machines.

More recently, it has become common practice to digitally grasp design data or manufacturing data of a product in two-dimensional, three-dimensional, but at least reproducible production parameters. This can regularly with little effort a target image of the test object or Workpiece are derived. Optionally, the coordinate spaces underlying the actual image and the target image may also be related to each other during the measurement, for example superimposed on one another. In this way, the measurement results can also be evaluated "digitally". This allows, for example, conclusions about to be changed manufacturing parameters or design elements of the workpiece.

Coordinate metrology usually allows trouble-free testing of DUTs or workpieces. Thus, in principle a high suitability for the production-accompanying examination is given, in particular for one hundred percent control. However, in addition to such routine tasks, coordinate metrology is also particularly suitable for carrying out individual measurements. As a rule, within a measuring volume (or measuring space) provided by a coordinate measuring machine, any or almost any point can be touched, so that no special preparations are required for measuring a measuring object or workpiece, insofar as it can be placed in the measuring volume. In particular, a structural adaptation of the coordinate measuring machine to the measurement object or, conversely, a structural adaptation of the measurement object to the coordinate measuring machine can be avoided on a regular basis. Such adjustments are often required for gauges or similar "single-purpose gauges".

There are various types of coordinate measuring machines are known, which differ, for example, by the type of probing of the measuring object or workpiece. The probing of the workpiece, for example, can be done without contact. On the other hand, a tactile adaptation is conceivable. A tactile, touching probing can be done by means of a tactile probe, which is designed as a passive or active tactile sensor. Non-contact, such as optical, probing may include optical edge detection, optical distance determination, or the like. The distance determination may be similar to a tactile probing, but instead of touching the workpiece in question about a focus can be done. A distance value that can be determined in this way allows an "indirect" position determination. Furthermore, triagulation methods or similar approaches for optical adaptation are conceivable. Optical detection by means of edge detection can take place, for example, by using sensor packages arranged in line form, line form or matrix form, which are designed, for example, to detect threshold values which can be attributed, for example, to an edge transition. Under the optical probing principle can be understood a non-contact probing using optical sensors.

In addition to individual probing of geometric elements (also: entities) of the workpiece, continuous or quasi-continuous measurements are conceivable in which a probe also optically or tactually touches the workpiece during a relative movement between the workpiece and the sensor carrier. In this way, curves or surfaces can be detected. Thus, it is conceivable to detect an envelope contour of the workpiece, which is essentially formed by a point cloud whose number of points or point density is determined by a sampling rate of the probe or sensor during the relative movement between the sensor and the workpiece.

Single-purpose coordinate measuring machines are known in the prior art, which are designed specifically for tactile probing or optical probing. Universal coordinate measuring machines are also known, which are in particular designed to be operated both with tactile sensors (probes) and with optical sensors (probes). For this purpose, the sensor carrier of such a coordinate measuring machine can have at least one receptacle which is designed both for receiving tactile probes and for accommodating optical probes.

By way of example, an optical probe can comprise a lens with an evaluation unit which is designed to acquire visual data. In particular, it may be about a telecentric zoom lens. Frequently, optical probes or sensors require a defined illumination of the workpiece to be measured. Depending on the measuring task, it is conceivable to illuminate the workpiece by means of incident light sources, transmitted light sources or perspective light sources. Perspectively arranged light sources can be aligned approximately at a defined angle to the optical axis of the optical sensor. These may be stripe light sources or the like for triangulation measurements. Reflected light sources may in principle be arranged parallel to the optical axis of the optical sensor or at an acute angle to the optical axis of the optical sensor. Incident light sources may be formed, for example, by a plurality of annularly arranged light sources which are arranged in a circle around the optical axis of the optical sensor. Transmitted light sources can be provided on a side of the test object or workpiece facing away from the optical sensor in order to illuminate it "from behind".

Transmitted light sources allow high-contrast illumination, in particular of workpiece edges. In this way, peripheral contours, edges or the like can be detected with high precision and efficiency. Coordinate measuring machines used for optical measurement of illuminated by transmitted light workpieces are usually on at least partially optically transmissive measuring table, on which the workpiece is receivable. On one side of the measuring table (usually: upper side), the sensor carrier is arranged with the optical probe or sensor. On a side facing away from the optical probe or sensor side of the measuring table (usually: bottom), the transmitted light source is arranged.

In the (optical) probing of the workpiece relative movements between the workpiece and the (optical) sensor or probe are regularly required. Accordingly, the transmitted light source must be moved or moved in a suitable manner in order to ensure the most constant measurement conditions can. In the prior art known coordinate measuring machines, which are suitable for transmitted light measurements, have about a (mechanical) coupling between the transmitted light source and the sensor carrier, which causes entrainment of the transmitted light source during the relative movement between the sensor carrier and the workpiece.

Against this background, the invention has for its object to provide a coordinate measuring machine and a corresponding method for measuring workpieces, which allow a flexible and efficient measurement of workpieces. In particular, measurement inaccuracies should be reduced as much as possible. In addition, the coordinate measuring machine should be as suitable as possible for the use of different buttons or sensors and for the use of different lighting concepts.

According to one aspect of the invention, this object is achieved by a coordinate measuring machine of the type mentioned, wherein a coupling unit is provided which is adapted to selectively decouple the at least one transmitted light source from the movable sensor carrier, wherein the at least one transmitted light source and the movable sensor carrier selectively engageable traction means is interposed, wherein the traction means comprises a driver which is fixed to the traction means, and wherein the coupling unit comprises a gripper with at least one engageable with the driver gripping member which is displaceable between a driving configuration and a release configuration.

The object of the invention is completely solved in this way.

In accordance with the invention, the coupling unit makes it possible to drive the at least one transmitted-light source in the desired manner precisely when a transmitted-light measurement actually takes place. In other operating conditions, such as when measured by incident light or when tactile sensors are used, the connection of at least one transmitted light source can be solved with the movable sensor carrier, so that no drive and no entrainment must be done. In this way, the inertia of the sensor carrier during measuring operations in which the entrainment of the transmitted light sources is not required to be significantly reduced. The measurement can basically be done faster and / or with higher accuracy. The selective decoupling of the transmitted light source can also help to significantly reduce wear on the transmitted light source and on components intended to entrain it. The transmitted light source may more often remain in an idle state.

For the purpose of this disclosure, the terms "coupling" (also: "coupling" or "coupling in") and "decoupling" (also: "decoupling") can in principle be used with the terms "coupling" (also "engaging") or "disengaging" be equated. The coupling or coupling may include a targeted "engagement" of the coupling unit, whereby the entrainment of the transmitted light source is made possible with the movable sensor carrier. Conversely, the decoupling or disengaging may include a "disengagement" of the coupling unit to prevent the entrainment of at least one transmitted light source.

The selective decoupling or decoupling of the at least one transmitted light source from the movable sensor carrier may in principle comprise complete decoupling. In the decoupled state, complete decoupling can permit free (direction-independent) relative movements between the movable sensor carrier and the at least one transmitted light source. However, the decoupling can also take place in such a way that only direction-bound free relative movements between the at least one transmitted light source and the movable sensor carrier are permitted in the decoupled state. This can be understood, for example, as meaning that no entrainment of the at least one transmitted light source by the movable sensor carrier is permitted in a movement direction along a movement axis. In the opposite direction along this movement axis, however, a motion entrainment of the at least one transmitted light source by the movable sensor carrier can continue to be provided. Accordingly, the coupling unit may be formed according to various embodiments as a directional coupling.

In the coupled or coupled state, the movement entrainment of the at least one transmitted light source by the movable sensor carrier can take place such that the transmitted light source can be moved synchronously with the sensor carrier. In other words, the transmitted light source the Follow sensor carrier during its movement to ensure a desired illumination or illumination of the test object or workpiece. For example, it may be desirable for a center or a central axis of the at least one transmitted light source to essentially coincide with an optical axis of the optical sensor. It is understood that the illumination unit can in principle also comprise a plurality of transmitted light sources. The illumination unit can in particular allow a planar illumination of the workpiece.

The measuring table, on which the workpiece is directly or indirectly receivable, is at least partially optically transparent. Optical transmission may include at least partial transparency. By way of example, the measuring table may comprise an at least partially transparent plate, such as a glass plate or the like. In this way, the recorded workpiece can be "backlit" through the plate illuminated. In principle, it is also conceivable to introduce defined recesses into the measuring table, for example a multiplicity of perforations or holes which are transparent. The illumination of the workpiece can be done in particular by means of visible light. Visible light can generally be understood as that part of the electromagnetic radiation that is (usually) visible to the human eye. It is understood that the optical sensor can also be designed to detect "visible" light. However, it is also conceivable that the optical sensor is designed to detect electromagnetic radiation whose wavelengths are outside the spectrum visible to the human eye. Accordingly, the at least partially optical transmission of the measuring table can generally relate to parts of the electromagnetic spectrum which are "visible" to the respectively installed optical sensor.

By way of example, the coordinate measuring machine can be designed as a 3-axis coordinate measuring machine, which permits a relative movement between the sensor received on the sensor carrier and the workpiece along three axes (for example: X, Y, Z), which are preferably arranged perpendicular to one another. The coordinate measuring machine can be designed, in particular, in gantry construction or in column construction, and can have a machine frame and a plurality of slides which can be moved relative to the frame or relative to one another.

With a traction means, which is deflected in a suitable manner, the desired movement entrainment of the at least one transmitted light source in the coupled state can be effected in a simple manner with high repeatability. The selective decoupling can in particular also reduce wear on the traction means and on optionally provided deflection rollers. The traction means can in principle be formed as a strand-shaped traction means. The traction means may be generally designed for the transmission of tensile loads. It is understood, however, that the traction means may be at least partially designed for the transmission of shear loads, such as in the sense of a combined pull and push cable. Preferably, the traction means is formed as a rope, alternative embodiments of the traction means as a chain, belt, timing belt or the like are readily conceivable. The pulleys can be suitably adapted to the traction means. It is understood that in principle rigid deflections can be provided, such as cylinder sections or the like, along which the traction means can slide during the process.

The driver can be designed as a sleeve, nipple or the like. The driver can be connected in a suitable manner non-positively or positively with the traction means. Accordingly, the driver may be formed as a clamping sleeve, clamping ring, screw sleeve or in a similar manner. The coupling unit preferably has two gripping elements, which may be designed as gripping arms, for example. The gripping elements can be in the entrainment configuration in an engaged state. The gripping elements may be in a disengaged state in the release configuration. When engaged, the coupling of the driver is enabled. In the disengaged state, the driver can be released in at least one direction. In general, the at least one gripping element which can be coupled to the driver can be switched over between the entrainment configuration and the release configuration.

According to a further embodiment, the selectively engageable traction means is a circulating traction means. This embodiment is preferably further developed in that the traction means is formed as a rope, in particular as a closed circumferential endless rope, wherein the rope is deflected over a plurality of deflection rollers to move in the coupled state, the at least one transmitted light source synchronously with the movable sensor carrier.

According to a development, the driver has a driving contour, in particular a guide groove, to which the at least one gripping element can act. In particular, when the traction means is designed as a cable or cable, the driving contour can be designed as a rotationally symmetrical driving contour or rotationally symmetrical guide groove. Preferably, the driving contour has an at least partially wedge-shaped cross-section which corresponds to contact surfaces of the at least one gripping element. On In this way, a centering between the driver and the coupling unit may result upon engagement of the at least one gripping element in the driving contour. In this way, in the coupled state, the entrainment of at least one transmitted light source with high accuracy. Preferably, the entrainment of at least one transmitted light source with a reproducibility (also: repeatability) of about 0.3 mm maximum, preferably at most 0.1 mm, take place.

In the reverse manner, it is alternatively also conceivable that the driving contour on the driver has a raised guide contour, which can cooperate with a recessed counter-contour on at least one gripping element.

According to a further aspect, the coordinate measuring machine has a coupling unit with at least one electromagnet, which can be selectively activated for coupling or decoupling the at least one transmitted light source with the movable sensor carrier. By way of example, the at least one electromagnet can be selectively energized by a control device of the coordinate measuring machine.

According to a development of this embodiment, the electromagnet is designed as an actuator, in particular as a lifting magnet, for actuating the at least one gripper element, wherein the at least one gripping element and the at least one electromagnet a coupling drive, in particular a toggle mechanism, is interposed.

A coupling drive can translate or reduce a given stroke movement of the solenoid in the desired manner. By means of the coupling drive, it is possible to use only one electromagnet for (opposite) operation of two gripping elements. By means of a toggle mechanism, a high holding force for the at least one gripping element can be effected even with a low lifting force of the lifting magnet.

According to an alternative or additional development of the aforementioned embodiment, the at least one electromagnet is designed for the force-driven entrainment of the driver, wherein the driver is at least partially formed from a magnetizable or a permanent magnetic material. In this way, the driver can be entrained by generating magnetic forces frictionally. It is understood that in addition an at least partially molded entrainment of the driver by the coupling unit is conceivable. For example, a magnetic attraction force can be used to produce a desired relative orientation between the driver, in particular the driving contour, and the coupling unit, in particular the at least one gripping element of the gripper.

According to a further embodiment, the coupling unit allows a direction-dependent entrainment of the driver in the release configuration. This design has the particular advantage that the driver can be transferred by a defined method of the movable sensor carrier in the release configuration in a rest position. In this way, the driver can then, when it is not needed, remain in a defined position in which it can be coupled in a simple manner for later use again. Usually, a possible range of movement of the driver in the coupled state is dependent on a range of movement of the movable sensor carrier. If now only a direction-dependent entrainment in the release configuration is made possible, the driver can be transferred to the rest position by targeted method of the sensor carrier in the direction in which the entrainment of the driver is possible. The rest position of the driver preferably corresponds to a maximum position, such as a maximum traversed position, of the sensor carrier.

If the coupling unit in the release configuration were disengaged in such a way that no entrainment of the carrier could take place any more, the (re) coupling of the carrier in different operating states could be associated with difficulties. It would not be guaranteed in any case that the coupling unit (or the control device of the coordinate measuring machine) exactly "knows" exactly where the driver is located. Of course, it would be conceivable to provide suitable sensors for detecting the position and / or position of the driver to facilitate the re-coupling of the driver with the coupling unit. However, this would lead to an increased effort.

According to a further embodiment of the aforementioned embodiment of the coupling unit for directional entrainment, the driver has a protruding portion and a recessed portion opposite the protruding portion, wherein the at least one gripping member in the driving configuration at both portions can engage the driver, and wherein the at least a gripping member in the release configuration can engage the protruding portion and is spaced from the recessed portion.

By way of example, the driver has a driving groove which is provided with two flanks, of which in the release configuration the at least one disengaged gripping element can take one. in the disengaged state, the at least one gripping element of the other of the two flanks is spaced such that no (lateral) entrainment (along the longitudinal extent of the traction means) is possible. Thus, the coupling unit may be configured in the driving configuration as a substantially rigid coupling and in the release configuration as a directional coupling.

In this context, it is further preferred if the coordinate measuring machine has an end stop, in particular an end stop with a stop buffer, which limits a movement of the driver, wherein the at least one gripping element in the release configuration can move the driver in the direction of the end stop. In this way, the driver in the decoupled state defined come to rest on the end stop. Thus, it would be conceivable in principle to dispense with complex sensors for detecting the position of the driver. Nevertheless, a secure (re) coupling the driver is still possible. Preferably, the end stop has at least one resilient element in order to minimize jerky or jerky loads on contact with the driver.

According to a further aspect, the coordinate measuring machine has a position detection unit, in particular a light barrier, for detecting an actual position of the driver, wherein the gripper in the release configuration can be moved relative to the driver into the actual position. A light barrier is generally a position detection element which can be realized easily and with little effort. The light barrier can be designed, for example, to detect whether the driver is in the actual position at the end stop. It is not generally necessary to detect where exactly the driver is currently located when it is not at the actual position. The driver can be moved in a simple manner in the direction of the actual position when the coupling unit in the release configuration allows a direction-dependent entrainment of the driver by the sensor carrier. Thus, the position detection unit can provide an acknowledgment that the driver is in the actual position. If the position detection unit signals the presence of the driver, the sensor carrier can be moved in a simple manner in a corresponding position to re-engage the driver.

According to a further embodiment, the coordinate measuring machine is designed as a 3-axis coordinate measuring machine, which has a machine frame with a first guide, along which the measuring table with the workpiece support is movable, further defining a receiving structure for the sensor carrier, in particular a portal, fixed to the frame on the machine frame is, wherein on the receiving structure, a second guide is formed, along which a carriage is movable, wherein on the carriage, a third guide is formed, along which the sensor carrier is movable, and wherein the machine frame further comprises an auxiliary guide for the lighting unit is formed in parallel is arranged to the second guide and along which the at least one transmitted light source is movable.

Preferably, the guides are aligned substantially perpendicular to each other. The coordinate measuring machine can basically comprise further axes. Thus, it is conceivable to design the probe or sensor for probing the workpiece pivotable to detect depressions, undercut areas or the like. Such functionality is particularly useful when the workpiece (also) is touched tactile. The receiving structure for the sensor carrier can basically have a portal shape. However, it is also conceivable to form the receiving structure for the sensor carrier as a stand or column.

It is further preferred if the traction means is firmly connected to the at least one transmitted light source for movement entrainment, wherein the coupling unit, in particular the gripper, is fixed to a movable carriage on which the sensor carrier is received. Thus, the coupling or disengaging in the region of the sensor carrier, close to the sensor, take place. If the transmitted light source is not required, it may remain in an idle state together with the traction means and optionally provided deflection rollers. This design has the further advantage that the inertia of the sensor carrier in the decoupled state can be significantly reduced. The composite of the lighting unit and the traction means, which is guided approximately over pulleys, can be considered as a spring-mass system that can be selectively decoupled. This spring-mass system would be excited in the movement entrainment in a certain way and affect the measurement accuracy of the coordinate measuring machine accordingly. Such effects can be prevented when moving the sensor carrier in the decoupled state. The measuring accuracy can be further increased.

• – Aufnehmen zumindest eines Werkstücks auf einem Messtisch mit einer Werkstückauflage;
• – Verfahren eines an einem Sensorträger aufgenommenen Tasters, insbesondere eines optischen Sensors, relativ zum Werkstück;
• – optisches oder taktiles Antasten des Werkstücks zum Erfassen von Messwerten;
• – im Durchlicht-Messbetriebsmodus, Koppeln zumindest einer Durchlichtquelle zur Bewegungsmitnahme mit dem verfahrbaren Sensorträger und Aktivieren der Durchlichtquelle zur Beleuchtung des Werkstücks; und
• – im Nicht-Durchlichtquelle-Messbetriebsmodus, Entkoppeln der zumindest einen Durchlichtquelle vom verfahrbaren Sensorträger, um den Sensorträger unabhängig von der Durchlichtquelle zu verfahren,

wobei der zumindest einen Durchlichtquelle und dem verfahrbaren Sensorträger ein selektiv einkoppelbares Zugmittel zwischengeordnet ist, wobei das Zugmittel einen Mitnehmer aufweist, der am Zugmittel festgelegt ist, und wobei die Kupplungseinheit einen Greifer mit zumindest einem mit dem Mitnehmer koppelbaren Greifelement aufweist, das zwischen einer Mitnahmekonfiguration und einer Lösekonfiguration verlagerbar ist.The object of the invention is further achieved by a method for measuring workpieces with a coordinate measuring machine, in particular a 3-axis coordinate measuring machine, which is operable in a transmitted light measuring mode of operation and in a non-transmitted light measuring mode of operation, the method comprising the following steps includes:

• - Receiving at least one workpiece on a measuring table with a workpiece support;
• - Method of a recorded on a sensor carrier probe, in particular an optical sensor, relative to the workpiece;
• - Optical or tactile probing of the workpiece for acquiring measured values;
• In the transmitted-light measuring mode of operation, coupling at least one transmitted-light source for moving movement with the movable sensor carrier and activating the transmitted-light source for illuminating the workpiece; and
• In the non-transmitted light source measuring operating mode, decoupling the at least one transmitted light source from the movable sensor carrier in order to move the sensor carrier independently of the transmitted light source,

wherein the at least one transmitted light source and the movable sensor carrier a selectively engageable traction means is interposed, wherein the traction means comprises a driver, which is fixed to the traction means, and wherein the coupling unit comprises a gripper with at least one engageable with the driver gripper element, which between a driving configuration and a release configuration is displaced.

Also in this way the object of the invention is completely solved.

Accordingly, the at least one transmitted light source can be moved in transmitted-light measuring mode synchronously with the sensor carrier on which the sensor is received. In non-transmitted-light measuring mode, the at least one transmitted-light source can be decoupled from the sensor carrier. The non-transmitted light measurement operation may include, for example, an optical measurement by incident light illumination or another type of illumination. Alternatively or additionally, the non-transmitted-light measuring operation may comprise a measurement by means of tactile scanning.

• – Im Nicht-Durchlicht-Messbetriebsmodus, Verfahren der zumindest einen Durchlichtquelle in einer Richtung bis in eine Endlage, insbesondere eine durch einen Endanschlag definierte Endlage, umfassend:
• – Überführen zumindest eines Greifelements einer Kupplungseinheit aus einer Mitnahmekonfiguration in eine Lösekonfiguration; und
• – richtungsabhängige Bewegungsmitnahme eines Mitnehmers durch die sich in der Lösekonfiguration befindende Kupplungseinheit in eine Endlage, insbesondere durch das zumindest eine Greifelement, wobei der Mitnehmer an einem Zugmittel festgelegt ist, mit dem die zumindest eine Durchlichtquelle zur Bewegungsmitnahme mit dem Sensorträger koppelbar ist.

According to a preferred development, the method also has the following:

• In the non-transmitted light measuring mode of operation, moving the at least one transmitted light source in one direction to an end position, in particular an end position defined by an end stop, comprising:
• - Transferring at least one gripping element of a coupling unit from a driving configuration into a release configuration; and
• - Direction-dependent Bewegungsmitnahme a driver by the clutch located in the release configuration in an end position, in particular by the at least one gripping element, wherein the driver is fixed to a traction means with which the at least one transmitted light source for Bewegungsmitnahme with the sensor carrier can be coupled.

The method of the transmitted light source and / or the method of the driver can be made approximately defined when a change between the transmitted light measuring mode of operation and the non-transmitted light measuring mode of operation takes place. However, it would also be conceivable to move the at least one transmitted light source piece by piece in the direction of the end position in non-transmitted-light measuring mode of operation. This can be done "incidentally", for example, if the at least one gripping element is moved in the direction of the end position anyway when the current measuring task is completed.

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.

Further features and advantages of the invention will become apparent from the following description of several preferred embodiments with reference to the drawings. Show it:

1 a perspective view of an embodiment of a coordinate measuring machine having a lighting unit with a transmitted light source;

2 an enlarged partial view of the coordinate measuring machine according to 1 , which has been omitted for illustrative purposes on the representation of various components;

3 a perspective view of an embodiment of a coupling unit which is coupled to a driver of a traction means partially shown;

4 a perspective view of another embodiment of a coupling unit which is coupled to a driver of a traction means partially shown;

5a to 5d highly simplified schematic representations of various coupling states and positions of gripping elements of a gripper and a driver of a traction device with respect to an end stop; and

6 a schematic flow diagram illustrating an embodiment of a method for measuring workpieces with a coordinate measuring machine.

1 shows a perspective view of an embodiment of a coordinate measuring machine, the total with 10 is designated. 2 shows an enlarged partial view of the coordinate measuring machine 10 , for illustration purposes in FIG 2 was dispensed with the representation of various components.

The coordinate measuring machine 10 is exemplified realized in a gantry design. The coordinate measuring machine (also: CMM) 10 has a machine frame 12 on, which can also be referred to as a machine bed or base plate. On the machine frame 12 is a carrier structure 14 received frame-fixed, which is designed here as a portal. The support structure 14 and the machine frame 12 are connected to each other very stiffly. The coordinate measuring machine 10 could be designed in an alternative manner as well as in stand construction, column construction or in other ways.

On the machine frame 12 is also a measuring table 16 recorded in the 1 basically executed in the form of a carriage. The measuring table 16 is in this case approximately relative to the machine frame 12 (and to the portal 14 ) slidably received. At the trained as a portal recording structure 14 is a sled 18 taken and relative to the portal 14 and to the machine frame 12 traversable. At the sled 18 is a sensor carrier 20 slidably received. The sensor carrier 20 may also be referred to as a sensor carriage, relative to the carriage 18 is displaceable. The sensor carrier 20 has a receptacle on which at least one button or sensor can be recorded. An example is the sensor carrier 20 an optical sensor 22 added. Preferably, the coordinate measuring machine 10 designed for both tactile (touching) and optical (non-contact) sensors 22 co.

The measuring table 16 , the sled 18 and the sensor carrier 20 are relative to each other and relative to the portal 14 or to the machine frame 12 movable and define a measuring space in which a measuring object or workpiece (in 1 not shown) is receivable and can be touched.

At the measuring table 16 may be an exemplified as a plate workpiece support 24 be included (in 1 completely transparent for illustrative purposes). At the workpiece support 24 it may in particular be an at least partially transparent plate. The workpiece support 24 may be in a suitable receiving structure or frame structure on the measuring table 16 be absorbed and fixed. The workpiece to be measured can be placed on the workpiece support 24 be filed. It is conceivable that the workpiece by its own weight safely on the workpiece support 24 is fixed. However, it is also conceivable, the workpiece by suitable clamping means (in 1 not shown) defined on the workpiece support 24 set.

The measuring table 16 , the sled 18 and the sensor carrier 20 can be described by way of example motorized. For this purpose, the measuring table 16 , the sled 18 and the sensor carrier 20 be provided with their own drives or be coupled with a common drive. It is also conceivable, at least one of the measuring table 16 , the sled 18 and the sensor carrier 20 to be moved manually. Nevertheless, motor drives are preferred.

For example only is in 1 one with 26 designated drive for the carriage 18 represented by about a spindle 28 interacts with this to the sled 18 along the portal 14 defined to proceed. Also the sensor carrier 20 and the measuring table 16 may similarly be provided with drives to be traversed in a defined manner.

In the 1 and 2 is each exemplified with X, Y, Z indicates a coordinate system whose axes with 30 . 32 and 34 are designated. The axis 30 can basically designate a longitudinal direction (X-axis). The axis 32 may basically designate a transverse direction or depth direction (Y direction). The axis 34 may basically designate a vertical or vertical direction (Z-direction). The axes 30 . 32 and 34 can each be aligned vertically (also: orthogonal) to each other. It is understood that the assignment of the coordinate system X, Y, Z shown to the coordinate measuring machine 10 or to its components by way of example only for illustrative purposes, and in principle can also be done in other ways. In particular, axis designations can be assigned to other orientations. It is understood that the preceding and following statements are readily applicable to (transformed) modified coordinate systems. In the same way, general directions, directions of rotation, details of relative assignments and details of absolute assignments, which relate to certain figures, can in principle also be transferred to other figures with modified viewing directions or view orientations.

The coordinate measuring machine 10 is exemplary here as a 3-axis coordinate measuring machine 10 trained and allowed by the interaction of its components, in particular the measuring table 16 , the sled 18 and the sensor carrier 20 , a defined method of the optical sensor 22 along each of the axes 30 . 32 . 34 in the provided Measuring room. It is basically conceivable, the coordinate measuring machine 10 otherwise, provided that the resulting relative movements can be effected. Furthermore, it is conceivable, the coordinate measuring machine 10 alternatively only as a 2-axis coordinate measuring machine. However, it is also conceivable, the coordinate measuring machine 10 something as a 4-axis or as a 5-axis coordinate measuring machine 10 to design. By way of example, in the case of a coordinate measuring machine designed as a 5-axis device 10 in addition to the three (translational) longitudinal axes ( 30 . 32 . 34 ) be provided at least two additional pivot axes. So it would be conceivable, suitable swivel actuators for the sensor 22 on the sensor carrier 20 take.

On the machine frame 12 is also a lighting unit 36 recorded, the at least one transmitted light source 38 includes. The lighting unit 36 is adapted to a workpiece to be measured by the designed as at least partially transparent plate workpiece support 24 through to illuminate. The optical sensor 22 and the at least one transmitted light source 38 are arranged on opposite sides of the at least partially transparent plate. By means of transmitted light illumination in particular outer contours, contours, silhouettes and the like of workpieces can be illuminated with high contrast. In this way, the (optical) detection and measurement of these design elements can be done with high accuracy.

In 1 is also a with 40 designated, schematically greatly simplified control device for the coordinate measuring machine 10 shown. The control device 40 can the coordinate measuring machine 10 supplied with energy and / or with operating media in a suitable manner. The control device 40 may also be adapted to the one or more drives for the measuring table 16 the sled 18 and / or the sensor carrier 20 Defined to drive to the sensor 22 to proceed in the desired manner. Furthermore, the control device 40 be designed for detecting and processing of detected (tactile and / or optical) probing.

The coordinate measuring machine 10 can also have a with 42 be designated, shown schematically greatly simplified input and output unit. The input and output unit 42 can be designed for the input of control commands. Furthermore, the input and output unit 42 for outputting information, such as the geometry of the workpiece and / or the operating state of the coordinate measuring machine 10 concerning, to be trained. Furthermore, the input and output unit 42 be provided with at least one interface, via which the coordinate measuring machine 10 Can exchange data. A data exchange can be done with external control devices, such as a measuring computer. A data exchange can also take place, for example, with a database in which, for example, a desired geometry of the workpiece currently to be measured is stored. However, data exchange may also include operating parameters of the CMM 10 concern, such as for maintenance and / or diagnostic purposes.

In a transmitted-light operating mode (or: transmitted-light measuring operating mode), the aim is to use the at least one transmitted-light source 38 synchronous with the optical sensor 22 , or with the sensor carrier 20 at which the optical sensor 22 is added to proceed. It is conceivable that at least one transmitted light source 38 to proceed such that an optical axis of the transmitted light source 38 with an optical axis of the optical sensor 22 coincides, or at least only small distances from this has.

It is known the lighting unit 36 with the at least one transmitted light source 38 via a traction mechanism drive 46 to couple with each other. The traction drive 46 can at least one traction means 48 have, preferably a closed circulating traction means. At the traction means 48 it can be a rope. Such a traction device or rope 48 In principle, it would also be possible to include at least one intermediate spring element which can effect length compensation or tolerance compensation. It is also conceivable, the traction means 48 as a belt, toothed belt, chain or the like.

According to the example in 1 shown configuration of the coordinate measuring machine 10 agree the location of the optical sensor 22 and the at least one transmitted light source 38 along the axis 32 (Y axis) match each other. To synchronize the movement of the sensor carrier 20 with the optical sensor received therein 22 and the at least one transmitted light source 38 it is therefore necessary to have their positions along the axis 30 (X-axis) as possible to bring into agreement and keep. For this purpose, the traction mechanism drive 46 be resorted to. The traction drive 46 may be suitably designed to be the sensor carrier 20 and the at least one transmitted light source 38 to couple together such that a method of the sensor carrier 20 along the axis 30 a directionally and magnitude equal movement of the transmitted light source 38 causes.

It is understood that during a movement of the sensor carrier 20 along the axis 34 (Z axis) no corresponding movement entrainment of the transmitted light source 38 is desired. Accordingly, for example, in the case of 1 shown embodiment of the coordinate measuring machine 10 the traction device 48 firmly with the sled 18 be connected along the portal 14 along the X-axis is movable. Thus, the method of the sensor carrier has 20 along the Z-axis has no influence or no effect on the position of the traction device 48 , Accordingly, it is understood that the coupling of the at least one transmitted light source 38 with the sensor carrier 20 may be designed as an indirect coupling to the movement entrainment along a spatial axis. At the in 1 The example shown here is the X-axis. The relative position of the sensor carrier 20 and the at least one transmitted light source 38 along the Y-axis is predefined on the frame side. Along the Z-axis, the sensor carrier can 20 also in the coupled state of the traction device 48 regardless of the transmitted light source 38 move. The location of the transmitted light source 38 along the z-axis is essentially fixed and predefined.

The movement entrainment of at least one transmitted light source 38 during longitudinal movements of the sensor carrier 20 along the X-axis is particularly desirable in transmitted-light measurement mode of operation. However, there are other modes of operation that do not rely on transmitted light. In such non-transmitted-light modes of operation such capture is not required or even undesirable. The steady entrainment and coupling of at least one transmitted light source 38 with the sensor carrier 20 can be about the traction drive 46 and in other components of the coordinate measuring machine 10 lead to wear, although the driving is not required. That on the basis of 1 and 2 illustrated coordinate measuring machine 10 points with the coupling unit 50 a device that allows the lighting unit 36 with the transmitted light source 38 selectively with the sensor carrier 20 (or the carriage 18 ) or to decouple from this. In this way, the transmitted light source 38 Be "shut down" when the coordinate measuring machine 10 is operated in a non-transmitted light measurement mode.

In the 2 shown partial view of the coordinate measuring machine 10 is done for illustrative reasons omitting the sensor carrier 20 with the sensor 22 and the measuring table 16 with the workpiece support 24 (see. 1 ). Based on 1 various guide devices and guide elements are explained which the relative movement of the measuring table 16 , the sled 18 and the sensor carrier 20 allow each other. The used guide devices or guides can be configured in particular as linear guides. It may be exemplified by sliding guides. The sliding guides may in particular be hydrodynamic sliding guides. Furthermore, it is conceivable to carry out the sliding guides as static sliding guides, for example as a hydrostatic sliding guide or as an aerostatic sliding guide. The guide can basically also be designed as a rolling element guide. Thus, it is conceivable to perform the guides as roller guides or ball guides, in particular as recirculating ball bearings. Other shape principles for the guides are conceivable.

Already related to 1 illustrated traversing movements of the measuring table 16 , the sled 18 as well as the sensor carrier 20 are made possible by leadership arrangements based on the 2 be explained in more detail. On the machine frame 12 is a Y-leadership 52a . 52b provided along the (in 2 not shown) measuring table 16 with the workpiece support 24 along the Y-axis (axis 32 ) is movable. The Y-leadership 52 is as a parallel guide consisting of the elements 52a and 52b educated. At the portal 14 is an X-guide 54a . 54b trained, along the carriage 18 in the X direction (axis 30 ) is movable. The X-guide has two parallel guide elements 54a and 54b on. The movement of the sled 18 along the X-guide 54 can by the drive 26 with the spindle 28 be effected. At the sled 18 is a Z-guide 56a . 56b formed along the (in 2 not shown) sensor carrier 20 in the direction of the Z axis (axis 34 ) is movably received. The Z-guide can also be configured as a parallel guide and two guide elements arranged parallel to one another 56a . 56b exhibit.

On the machine frame 12 Another guide is added, as an auxiliary guide 58 can be designated. The auxiliary guide 58 is essentially parallel to the X-guide 54 oriented. Along the auxiliary guidance 58 can the lighting unit 36 together with the at least one transmitted light source 38 along the X direction (axis 30 ). For this purpose, the lighting unit 36 not necessarily provided with a separate own drive. Rather, the transmitted light source 38 through the traction mechanism drive 46 with the sledge 18 and thus indirectly with the sensor carrier 20 be coupled to movements of the carriage 18 to be able to follow along the X-axis. Thus, according to the in the 1 and 2 shown embodiment of the coordinate measuring machine 10 the at least one transmitted light source 38 also (indirectly) by the drive 26 of the sled 18 be moved.

The auxiliary guide 58 for the transmitted light source 38 is exemplary in an interruption 60 the guide elements 52a . 52b the Y-guide on the machine frame 12 educated. At the guide elements 52a . 52b are also recesses or interruptions 62 formed by the traction means 48 is guided. The traction device 48 is designed as a closed, circulating traction means and can by a plurality of guides, deflections and / or pulleys on the coordinate measuring machine 10 be recorded and guided. In 2 are exemplary with 64a . 64b . 64c shown deflecting rollers, which has been omitted for illustrative reasons on an explicit designation of other pulleys. The pulleys 64a . 64b are on the portal 14 added. The pulley 64c is on the machine frame 12 added. The pulleys 64a . 64b . 64c may be compared with respect to a plane formed by the Y-axis and the Z-axis further corresponding, symmetrically arranged pulleys. Together, the pulleys can a track for the traction means 48 define, which has approximately the shape of an "8" (eight). The track can basically run flat. In the 2 illustrated eight-shaped track for the traction means 48 However, it extends substantially both in a plane formed by the X-axis and the Z-axis and in a plane formed by the X-axis and the Y-axis. The eight-shaped path allows in the coupled state a directionally identical and in particular equal amount Bewegungsmitnahme the at least one transmitted light source 38 during a movement of the sensor carrier 20 or the carriage 18 along the X axis. It is understood that further and / or different arranged deflection rollers and similar guide elements may be present.

As already indicated above, the coordinate measuring machine 10 the peculiarity of having that with the coupling unit 50 the traction drive 46 , in particular its traction means 48 , selectively coupled or uncoupled. In the prior art known coordinate measuring machines have at best rigid connections of traction means and corresponding carriage. Such rigid compounds are not selectively switchable.

At the in 2 shown configuration of the coordinate measuring machine 10 is the coupling unit 50 on the sledge 18 added. By way of example, the coupling unit 50 on a guide body 68 of the sled 18 be included in the also the guide elements 56a . 56b the Y-guide are formed. The traction device 48 of the traction mechanism drive 46 can basically be in an in 2 hidden area (see the dashed line 66 in 2 ) on the guide body 68 be passed without being taken away by this. The entrainment of the traction device 48 through the with the guide body 68 provided sledges 18 can by an actuation of the coupling unit 50 be effected. The coupling unit 50 has a gripper 72 which selectively engages the traction means 48 can be brought or out of engagement with the traction means 48 can be solved.

According to the in 2 illustrated configuration is the traction means 48 of the traction mechanism drive 46 fixed to the at least one transmitted light source 38 connected. The coupling or decoupling can by the carriage 18 recorded coupling unit 50 be effected. In principle, it would also be conceivable to exchange the components with one another in such a way that the coupling unit 50 firmly with the lighting unit 36 or whose at least one transmitted light source is connected, and that the traction means fixed to the carriage 18 connected is. In the 2 actually realized design, however, has several advantages over this modification. First of all, the uncoupling of the traction device allows 48 directly on the "drive", namely the slide 18 , a decommissioning of the traction device 48 and the pulleys 64a . 64b . 64c if the entrainment or the entrainment of the transmitted light source 38 is not required. Furthermore, attaching a coupling unit would 50 at the lighting unit 36 associated with a certain amount of space, possibly a weakening of the machine frame 12 would be required to make enough space. Such weakening of the machine frame 12 however, would result in a reduced overall stiffness of the CMM 10 accompanied. On the other hand, the required space for the coupling unit 50 on the sledge 18 be provided without causing significant reductions in the rigidity of the CMM 10 would.

Based on 3 and 4 Be advantageous embodiments of the coupling unit 50 illustrated. In 3 is one with 50a designated coupling unit shown in perspective. The coupling unit 50a can be about the sled 18 (see. 2 ) to be selectively engaged with the traction means 48 for taking the at least one transmitted light source 38 to be coupled. The coupling unit 50a has one with you 72a designated gripper on. The gripper 72a is designed to be with a driver 74a to cooperate firmly on the traction means 48 is included. In particular, the driver can 74a non-positively and / or positively with the traction means 48 be connected. About the driver 74a can the coupling unit 50a on the traction means 48 act. In the coupled state, a movement of the coupling unit 50a in a driving direction (reference numeral 76 in 3 ) a corresponding displacement or movement of the traction device 48 cause.

To activate or deactivate the gripper 72 has the coupling unit 50a an electromagnet or lifting magnet 78 on. The lifting magnet 78 can be generally referred to as an actuator. It is conceivable, instead of the lifting magnet 78 provide alternative actuators, such as alternative electric linear actuators, pneumatic actuators, fluidic drives or the like. The lifting magnet 78 can be via a coupling drive 80 the gripper 72a selectively with the driver 74a couple. For this purpose, the solenoid is 78 designed to be a plunger 82 in a stroke direction 83 Defined to move between two end positions back and forth. By way of example, the plunger 82 with a first coupling member 84a and a second coupling member 84b be connected and via this a lifting movement in a pivotal movement of a first arm 86a and a second arm 86b transfer. At the first arm 86a may be a first gripping element 88a be educated. At the second arm 86b may be a second gripping element 88b be educated. The first arm 86a can at a first pivot axis 90a be included. The second arm 86b can at a second pivot axis 90b be included. Overall, it can be in the coupling mechanism or coupling drive 80 to act a toggle mechanism. By a defined procedure of the ram 82 with the lifting magnet 78 can be the first gripping element 88a and the second gripping element 88b to be selectively moved towards and away from each other, with the driver 74a to be coupled. In particular, the first gripping element 88a and the second gripping element 88b in a driving contour 92a who are at the driver 74a is trained, intervene. At the driving contour 92a it may be, for example, a circumferential annular groove, which for example has a wedge-shaped or wedge-shaped cross-section, cf. also 5a to 5d ,

It is basically conceivable that the coupling unit 50 a gripper 72 with at least one gripping element 88 having. So it would be about as alternative to in 3 shown embodiment of the coupling unit 50a conceivable, a linear drive, such as the solenoid 78 to provide with a sufficiently large stroke, such as a fork-shaped gripper 88 directly, without intermediate coupling drive 80 , radially in the direction of the driver 74 can proceed, cf. the double arrow 83 in 3 , Other designs of gripping elements 88 of the gripper 72 are conceivable without further ado.

4 illustrates an alternative embodiment of a gripper 72 a coupling unit 50 , One with 50b designated coupling unit has a 72b designated gripper, which with an actuator 94 is provided, which may in principle be an electric motor drive. Alternatively, the actuator 94 also have an electromagnet or a comparable drive, such as a hydraulic or pneumatic cylinder. The actor 94 is with a first gripping element 96a and with a second gripping element 96b coupled. The actor 94 is designed to the gripping elements 96a . 96b move radially toward each other or move away from each other. Each of the gripping elements 96a . 96b has a groove-shaped or fork-shaped guide contour, which is designed to have a driving contour 92b one in 4 With 74b designated driver of the traction device 48 to be coupled at least partially positively. An example is the driving contour 92b of the driver 74b designed as a ball element. In the coupled state, a movement of the coupling unit 50b which is roughly through the in 2 With 18 designated carriage is caused, a corresponding entrainment of the driver 74b along the driving direction 76 cause. The coupled or engaged state of the coupling unit 50 in which the gripper 72 , in particular the at least one gripping element 88 . 96 , to the driving contour 92 of the driver 74 can also be described as a carryover configuration.

Each driving element 74 can also be configured in a special way, even in the actually decoupled or decoupled state of the coupling units 50a . 50b a selective entrainment, in particular a directional entrainment, the driver 74 to allow. For this purpose, for example, the driver 74b another, with 92c designated driving contour formed, which is designed approximately annular or cylindrical. In a decoupled state, which may also be referred to as a release configuration, the gripping elements 88a . 88b respectively. 96a . 96b be spaced apart so that no interference with the (primary) driving contour 92a respectively. 92b more is given. However, the gripping elements 88a . 88b respectively. 96a . 96b in the release configuration only so far apart that still one (directional) entrainment of the (secondary) driving contour 92c is possible. This can bring various benefits, which are discussed below in connection with the 5a . 5b . 5c and 5d be set out.

The 5a to 5d show in a schematically greatly simplified manner a portion of the traction device 48 , Further, each with the reference numeral 72 a gripper with a first gripping element 88a and a second gripping element 88b indicated. Advantageously, the driving contour 92a of the driver 74 a protruding section 98 and one opposite to the above section 98 setback section 100 on. The sections 98 . 100 can also be called a long flank 98 and short flank 100 the groove-shaped driving contour 92a be designated.

At the in 5a shown release configuration of the gripper 72 are the first gripping element 88a and the second gripping element 88b spaced apart by a measure e.

The distance e is greater than a maximum dimension d of the short edge 100 , Accordingly, for example, the carriage 18 together with the coupling unit 50 (see. 2 ) independent of the traction means 48 method become. However, the distance e is not larger than a maximum dimension D of the long edge 98 the driving contour 92a of the driver 74 , Accordingly, the driver 74 and thus also the traction means 48 during a movement of the gripper 72 in a driving direction 102 be taken, provided the first gripping element 88a and / or the second gripping element 88b in contact with the long flank 98 the driving contour 92a can occur. To limit this movement, the coordinate measuring machine 10 advantageously with a stop or end stop 104 be provided. The stop 104 can be a takeaway of the driver 74 along the driving direction 102 limit. The stop 104 especially with a buffer or bump stop 106 be provided. The stop buffer 106 can be designed as an elastic buffer. By way of example, this can be done at the stop 104 a spring element 108 be provided. The spring element 108 basically allows a certain flexibility at least the stop buffer 106 , see. one with 112 designated arrow in 5a , It is understood that also the stop buffer 106 itself can be designed resilient. For example, it could be a rubber buffer. The stop buffer 106 allows a gentle attachment of the driver 74 at the end stop 104 , The end stop 104 can exemplify the portal 14 be educated.

In 5b is the gripper 72 in the driving configuration, wherein the first gripping element 88a and the second gripping element 88b moved toward each other (see arrows 116a . 116b in 5b ) that wedge-shaped end pieces of the gripping elements 88a . 88b in the driving contour 92a between the sections 98 . 100 can intervene. In this way, a takeaway of the driver 74 and consequently the traction means 48 in both directions, cf. one with 114 designated double arrow in 5b , For example only is in 5b furthermore one with 120 designated position detection unit shown schematically. In the position detection unit 120 it may, for example, be a light barrier, in particular a laser light barrier. The light barrier can basically be designed as a fork light barrier. The position detection unit 120 may be designed primarily to detect whether the driver 74 in its final position at the end stop 104 located. A detection of this condition may be advantageous when the coupling unit 50 should be activated to a desired coupling between the at least one transmitted light source 38 and the sensor carrier 20 to produce, cf. 1 and 2 ,

Based on 5c is illustrated that the driver 74 also in the release configuration of the gripper 72 in its final position at the end stop 104 can be moved. Starting from the in 5b shown entrainment configuration are the first gripping element 88a and the second gripping element 88b disengaged and spaced apart, cf. arrows 118a . 118b in 5c , Accordingly, only one entrainment of the driver 74 through the gripper 72 in a driving direction (arrow 102 ). The driver 74 can be defined or "random" towards the end stop 104 be moved. It is understood that also the movement of the gripper 72 , the clutch unit 50 is assigned to the sledge 18 can be included, can be limited. Accordingly, a desired end position for the driver 74 with a target end position for the gripper 72 match, by a target end position for the slide 18 is conditional.

This design has the particular advantage that no complex position detection or position detection for the driver 74 is required in order to selectively couple this again. The basis of the 5b illustrated position detection unit 120 can be particularly simple, such as a light barrier, trained. However, it is also conceivable, entirely on the position detection unit 120 to renounce. This would require the driver 74 through the gripper 72 in the release configuration (one-sided) in the driving direction 102 to proceed until the driver 74 at the end stop 104 comes to the plant. For a new coupling of the carriage 18 with the coupling unit received thereon 50 , the gripper 72 is associated, in turn, be moved to this position.

This condition or location assignment is in 5d illustrated. If the driver 74 and the gripper 72 located in matching end positions, the first gripping element 88a and the second gripping element 88b be moved towards each other to the desired coupling with the driver 74 , in particular with its driving contour 92a to manufacture.

Based on 6 illustrate various aspects of an embodiment of an exemplary method for measuring workpieces, in particular with a coordinate measuring machine 10 according to one of the aforementioned aspects can be performed.

In a step S10, the method, for example a measurement task, is initialized. It may be followed by a step S12, in which a measurement object or a workpiece is recorded on a recording. It may be followed by a step S14, in which it is decided whether a transmitted light source is to be coupled for movement entrainment, or whether a measurement with a decoupled transmitted light source is to be performed. A measurement with a transmitted light source coupled in can take place in particular in a transmitted-light measuring operating mode in which a coupling unit is in a driving configuration. A measurement with a decoupled or decoupled transmitted-light source can take place, for example, in a non-transmitted-light measuring operating mode in which the coupling unit is in a release configuration.

Depending on the decision made in step S14, a step S16 can be followed, which includes the coupling of the at least one transmitted light source for movement entrainment. It is understood that the step S16 may also include an upstream check whether the transmitted light source is not already coupled.

It may be followed by a step S18, in which a sensor carrier is moved with a sensor relative to the workpiece to be measured. The coupled at least one transmitted light source can move synchronously along at least one axis together with the sensor carrier. It may be followed by a step S20, in which the transmitted light source is activated for transmitted light illumination. In a further step S22, the measurement object or workpiece to be measured can be optically touched.

If the decision is made in step S14 to perform a measurement with decoupled transmitted light source, step S30 may follow. At step S30, the clutch unit may be transferred from the drive configuration to the release configuration. However, step S30 may also include a preliminary check as to whether the clutch unit is not already in the release configuration.

It may be followed by a further decision step S32, in which it is decided whether, for example, an optical probing (without transmitted light) or a tactile probing is to take place. If it is decided in step S32 to perform an optical touch, a step S34 may be followed, which includes a method of the sensor carrier relative to the workpiece. In a subsequent step S36, an illumination unit for an optical sensor (but not the transmitted light illumination unit) can be activated. It may be followed by the step S38, in which the workpiece is optically touched.

If, in step S32, the alternative decision is made to tactively touch the measurement object or workpiece, step S40 can follow, in which the sensor carrier (with the tactile probe or sensor) is moved relative to the workpiece. In a subsequent step S42, the workpiece can be touched tactilely with the tactile sensor.

The steps S22, S38 and S42 may be merged in a step S50. Step S50 may include acquiring values, in particular geometry data. It may be followed by a step S52, which terminates the process.

It is understood that, in particular, the steps S14 to S50 can be repeated several times during the measurement of a test object or workpiece. It is conceivable to make different decisions on different runs. Accordingly, a workpiece can be measured in different measurement modes. The measurement modes may include tactile probing and optical probing. Optical measurement modes can be performed on the one hand with transmitted light illumination, on the other hand also with incident light or alternative illumination methods.

The measuring method or the coordinate measuring machine that is suitable for carrying out this measuring method can be used in a highly flexible manner for various measuring tasks and can make use of the advantages of different measuring principles in order to efficiently and precisely fulfill the respective measuring task.

Claims (14)

Coordinate measuring device for measuring workpieces, with a measuring table ( 16 ) for receiving a workpiece, with a sensor carrier ( 20 ) along at least one axis of movement (X, Y, Z) relative to the measuring table ( 16 ) is movable, wherein the sensor carrier ( 20 ) with an optical sensor ( 22 ) can be coupled to the measurement of workpieces, wherein the measuring table ( 16 ) an at least partially optically transparent workpiece support ( 24 ), and with a lighting unit ( 36 ) for illuminating the workpiece, the at least one movable transmitted light source ( 38 ), wherein the at least one transmitted light source ( 38 ) for movement movement with the movable sensor carrier ( 20 ) can be coupled, characterized by a coupling unit ( 50 ), which is adapted to the at least one transmitted light source ( 38 ) selectively from the movable sensor carrier ( 20 ), wherein the at least one transmitted light source ( 38 ) and the movable sensor carrier ( 20 ) a selectively engageable traction means ( 48 ), wherein the traction means ( 48 ) a driver ( 74 ), which on the traction means ( 48 ), and wherein the coupling unit ( 50 ) a gripper ( 72 ) with at least one with the driver ( 74 ) coupling gripping element ( 88 ; 96 ) which is displaceable between a driving configuration and a release configuration. Coordinate measuring machine according to claim 1, characterized in that the selectively Coupling traction means ( 48 ) a circulating traction means ( 48 ). Coordinate measuring machine according to claim 1 or 2, characterized in that the driver ( 74 ) a driving contour ( 92 ), in particular a guide groove, on-points, to which the at least one gripping element ( 88 ; 96 ) can intervene. Coordinate measuring machine according to one of the preceding claims, characterized by a coupling unit ( 50 ) with at least one electromagnet ( 78 ), for coupling or decoupling the at least one transmitted light source ( 38 ) with the movable sensor carrier ( 20 ) is selectively activated. Coordinate measuring machine according to claim 4, characterized in that the at least one electromagnet ( 78 ) as an actuator, in particular as a lifting magnet, for actuating the at least one gripping element ( 88 ; 96 ) is formed, and that the at least one gripping element ( 88 ; 96 ) and the at least one electromagnet ( 78 ) a coupling drive ( 80 ), in particular a toggle mechanism, is interposed. Coordinate measuring machine according to claim 4, characterized in that the at least one electromagnet ( 78 ) for the force-driven entrainment of the driver ( 74 ) is formed, and that the driver ( 74 ) is at least partially formed of a magnetizable or a permanent magnetic material. Coordinate measuring machine according to one of the preceding claims, characterized in that the coupling unit ( 50 ) in the release configuration a direction-dependent entrainment of the driver ( 74 ) allowed. Coordinate measuring machine according to claim 8, characterized in that the driver ( 74 ) a protruding section ( 98 ) and one opposite the protruding section ( 98 ) reset section ( 100 ), wherein the at least one gripping element ( 88 ; 96 ) in the entrainment configuration at both sections ( 98 . 100 ) to take the driver ( 74 ), and wherein the at least one gripping element ( 88 ; 96 ) in the release configuration can attack the protruding section ( 98 ) and from the reset section ( 100 ) is spaced. Coordinate measuring machine according to claim 7 or 8, characterized by at least one end stop ( 104 ), in particular with a stop buffer ( 106 ), a movement of the driver ( 74 ), wherein the at least one gripping element ( 88 ; 96 ) in the release configuration the driver ( 74 ) in the direction of the end stop ( 104 ) can proceed. Coordinate measuring machine according to one of the preceding claims, characterized by a position detection unit ( 120 ), in particular a light barrier, for detecting an actual position of the driver ( 74 ), whereby the gripper ( 72 ) in the release configuration relative to the driver ( 74 ) Is movable in the actual position. Coordinate measuring machine according to one of the preceding claims, characterized in that the coordinate measuring machine is designed as a 3-axis coordinate measuring machine, which is a machine frame ( 12 ) with a first guide (Y), along which the measuring table ( 16 ) with the workpiece support ( 24 ), further comprising a receiving structure ( 14 ) for the sensor carrier ( 20 ), in particular a portal, fixed to the frame on the machine frame ( 12 ), wherein at the receiving structure ( 14 ) a second guide (X) is formed, along which a carriage ( 18 ) is movable, wherein the carriage ( 18 ) a third guide (Z) is formed, along which the sensor carrier ( 20 ) is movable, and wherein on the machine frame ( 12 ) an auxiliary guide ( 58 ) for the lighting unit ( 36 ) is arranged, which is arranged parallel to the second guide (X) and along which the at least one transmitted light source ( 38 ) is movable. Coordinate measuring machine according to one of the preceding claims, characterized in that the traction means ( 48 ) fixed to the at least one transmitted light source ( 38 ) is connected to the movement entrainment and that the coupling unit ( 50 ), in particular the gripper ( 72 ), on a movable carriage ( 18 ) at which the sensor carrier ( 20 ) is recorded. Method for measuring workpieces with a coordinate measuring machine, in particular a 3-axis coordinate measuring machine, which is operable in a transmitted-light measuring operating mode and in a non-transmitted-light measuring operating mode, comprising the following steps: - picking up at least one workpiece on a measuring table ( 16 ) with a workpiece support ( 24 ); Method of a sensor carrier ( 20 ), in particular an optical sensor ( 22 ), relative to the workpiece; - Optical or tactile probing of the workpiece for acquiring measured values; In the transmitted light measuring mode, coupling at least one transmitted light source ( 38 ) for movement movement with the movable sensor carrier ( 20 ) and activating the transmitted light source ( 38 ) for illuminating the workpiece; and - in the non-transmitted light measuring mode of operation, decoupling the at least one transmitted light source ( 38 ) from movable sensor carrier ( 20 ) to the sensor carrier ( 20 ) regardless of the transmitted light source ( 38 ) to proceed; wherein the at least one transmitted light source ( 38 ) and the movable sensor carrier ( 20 ) a selectively engageable traction means ( 48 ), wherein the traction means ( 48 ) a driver ( 74 ), which on the traction means ( 48 ), and wherein the coupling unit ( 50 ) a gripper ( 72 ) with at least one with the driver ( 74 ) coupling gripping element ( 88 ; 96 ) which is displaceable between a driving configuration and a release configuration. The method of claim 13, further comprising, in the non-transmitted-light measuring mode of operation, processes of the at least one transmitted-light source. 38 ) in one direction to an end position, in particular an end position defined by an end stop, comprising: transferring at least one gripping element ( 88 ; 96 ) a coupling unit ( 50 ) from a drive configuration into a release configuration; and direction-dependent movement of a driver ( 74 ) by the coupling unit in the release configuration ( 50 ) in the end position, in particular by the at least one gripping element ( 88 ; 96 ), the driver ( 74 ) on a traction means ( 48 ) is fixed, with which the at least one transmitted light source ( 38 ) for movement movement with the sensor carrier ( 20 ) can be coupled.

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