Measuring system, measuring arrangement, and method for determining measuring signals during a penetration movement of a penetration body into a surface of a test body

A measuring system for detecting measuring signals during a penetration movement of a penetration body into a surface of a test body, including a housing with a power generating device, which is operatively connected to a penetration body for generating a displacement movement of the penetration body along a longitudinal axis of the housing, and which actuates a penetration movement of the penetration body into the surface of the test body to be examined, or which positions the penetration body on the surface of the test body for scanning, and having at least one first measuring device for measuring the penetration depth into the surface of the test body or a displacement movement of the penetration body along the longitudinal axis of the housing during a scanning movement on the surface of the test body. The power generating device is actuated by a pressure medium for the penetration movement of the penetration body.

The invention relates to a measuring device as well as a measuring arrangement and a method for detecting measuring signals during a penetration movement of a penetration body in a surface of a test body, and also for identifying the scratch resistance of the surface of the test body.

A measuring device and a method for measuring the scratch resistance of a surface of a test body are known from DE 699 17 780 T2 which has a measuring table for accommodating a test body as well as a handling apparatus for transferring the measuring device from an initial position into a measuring position. Furthermore, a controller is provided by means of which both a travelling movement of the measuring table along an axis and a penetration movement of the penetration body is controlled [lacuna] by the measuring device after the placing of a test body on the surface to be tested, such that the penetration body penetrates the surface of the test body during the travelling movement of the measurement table.

The measuring device has a piezoelectric actuator for controlling the penetration movement of the penetration body after the placement on the surface of the test body, said actuator supplying a first holding plate which is moveable up and down by means of two leaf spring pairs. This holding plate accommodates a further plate which is in turn mounted in a manner which is moveable up and down, wherein the penetration body is arranged in this plate. A measuring device is provided between the holding plate and the plate accommodating the penetration body, said measuring device measuring the penetration path. Furthermore, a measuring device for identifying the normal force is arranged adjacently.

This measuring device has the disadvantage that a constructively complex and heavy structure is provided by the holding plate and by the plate accommodating the penetration body, as well as by the leaf spring pairs which are respectively selected for mounting. Thus, not only are large overall dimensions necessary, but also the piezoelectric drive must be designed to be correspondingly large in order to apply the force for controlling a penetration movement. Furthermore, this measuring device is slow due to the complex and constructive structure. Furthermore, the measuring device is costly due to the control of the penetration body by means of a highly precise piezoelectric actuator.

A hardness measuring instrument is known from JP 63-171 339 A which has a penetration body for introducing a scratch into a measuring surface in a moveable carriage. The penetration movement of the penetration body is controlled by an oil pressure chamber by the control pressure being raised by a hydraulic pump. This device has the disadvantage that the system is slow. A scanning movement for detecting the surface roughness is not possible.

The object of the invention is to create a measuring device for detecting measuring signals during a penetration movement of a penetration body into a surface of a test body, in particular for identifying the scratch resistance of the surface of the test body or for detecting measuring signals during a scanning movement of a penetration body on the surface of the test body, in particular for identifying the surface roughness of the test body, and a measuring arrangement as well as a method for identifying measuring signals during a penetration movement of a penetration body, in particular for identifying the scratch resistance of the surface of the test body or during a scanning movement of the penetration body, whereby an increased accuracy and a cost reduction are enabled.

This object is solved by a measuring device having a penetration body and having a force generating apparatus, to which the penetration body is operatively connected and penetrates a surface to be measured of the test body or scans a surface to be measured of the test body and having at least one measuring device for measuring the depth of penetration or the surface roughness, in which the force generating apparatus is controlled by means of a gaseous pressure medium for the penetration movement or for the scanning movement of the penetration body. The use of such a force generating apparatus, which controls the penetration movement or the scanning movement of the penetration body by means of a pressure medium, has the advantage that the pressure supplied by means of the penetration movement can be directly converted into a penetration movement, i.e. an increase in the pressure force corresponds to a direct increase in the force for the penetration movement, and vice versa. During a scanning movement, the supplied pressure preferably acts in the force generating apparatus as a rigid actuating member, whereby the changes in the surface of the test body can be transferred to the force generating apparatus and preferably to a sensor element. A simple and direct control can thus be enabled. Additionally, such a force generating apparatus operating with a pressure medium has a low mass and thus a low mass slowia. Such a force generating apparatus, which operates by means of a pressure medium, is thus furthermore enabled to be independent of temperature changes, because a change in temperature affects the pressure directly and this pressure can be immediately readjusted by the force generating apparatus. A constant pressure for the penetration movement or the scanning movement can thus be maintained. In particular with a plurality of measurements, there can thus be continuity and an increased measurement security.

Preferably, the force generating apparatus has a pressure chamber having at least one first pressure surface which is operatively connected to the penetration body. Thus, with an increase in a pressure, a direct penetration movement of the penetration body can be controlled. Additionally, higher forces can thus be generated with an overall dimension size which is still sufficiently low.

The force generating apparatus having a pressure chamber preferably has an inlet opening and an outlet opening which are provided outside of or adjacent to the pressure surface in the pressure chamber. The pressure surface can thus be orientated exclusively in the direction of the penetration body and cooperate with this penetration body, such that the inlet and outlet opening are preferably arranged laterally to at least one first pressure surface and thus cannot directly influence the pressure surface.

The pressure generating apparatus preferably comprises at least one pump, through which the pressure medium is delivered to the pressure chamber. The pump can thus be controlled in a regulated manner, such that it determines the pressure in the pressure chamber directly.

Furthermore, an inlet control valve is preferably provided upstream of the inlet opening of the pressure chamber and an outlet valve is preferably provided downstream of the outlet opening of the pressure chamber. A pressure in the pressure chamber can thus be maintained and/or adjusted in a simple manner by such control valves.

A further preferred embodiment of the force generating apparatus provides a storage container between the pump and the inlet control valve or the inlet opening. Thus, for example, the pump can be formed to be relatively small, such that the control of the pressure chamber and the provision via the storage container by means of the pressure medium takes place as required. Additionally, pressure peaks generated by the pump can be reduced with a direct feed of the pressure medium from the pressure chamber.

The pressure chamber preferably has a second pressure surface which is opposite the first pressure surface. The pressure chamber can thus be formed in a simple form, for example as a pressurised can which has two opposite pressure surfaces, such that the pressure acting in the interior of the pressure chamber acts uniformly on both pressure surfaces.

Furthermore, the pressure chamber is preferably provided in a housing, on whose side wall or peripheral wall the inlet and outlet opening is arranged and which has a first pressure surface on a lower side. This represents a simple and cost-effective design of the measuring device, as well as a space-efficient integration of the pressure chamber in the measuring device.

Furthermore, a sensor is preferably assigned to the second pressure surface of the pressure chamber outside of the pressure chamber. A displacement of the second pressure surface can thus be detected by means of this sensor in order to detect the actual acting pressure force which is exerted on the penetration body due to the pressure prevailing in the pressure chamber.

Furthermore, the pressure chamber is preferably formed as a can which can be inserted into the housing. This has the advantage that calibrated pressurised cans can be integrated into a housing in a simple manner.

The first and second pressure surfaces are preferably formed as a pressure membrane, said pressure surfaces being orientated parallel to each other. Consequently, a fixed peripheral wall is provided therebetween, in which the inlet and outlet opening are arranged and preferably fastened to the peripheral wall of the housing. The pressure membrane can preferably be fastened to the peripheral wall by means of a fastening ring, whereby there can be a simple assembly of the pressure chamber.

Furthermore, the pressure chamber preferably has freedom of movement in only one degree of freedom. This one degree of freedom is preferably located in the longitudinal central axis of the housing, i.e. in a Z axis, which the infeed movement of the penetration body for penetrating the surface is also located.

Furthermore, the first measuring apparatus for measuring a travel path of the penetration body, in particular the depth of penetration of the penetration body or the scanning movement for identifying the surface roughness of the penetration body, is preferably provided between the first pressure surface, the pressure chamber and the penetration body. This in turn leads to a compact structure.

Furthermore, a further measuring apparatus for detecting a displacement of the penetration body along at least one axis is provided between the first pressure surface and the penetration body for a compact structure of the measuring device, said measuring apparatus corresponding to the travelling movement of the test body relative to the penetration body, in particular when a scratch resistance test is being carried out. Preferably, this further measuring apparatus is also positioned in the same Z axis as the first measuring device.

Furthermore, alternatively, the further measuring apparatus for detecting a displacement of the penetration body can be detected along the axis which corresponds to the travel path of the test body relative to the penetration body and also identified in an axis orientated at a right angle thereto. This further measuring apparatus can thus detect changes in the position of the penetration body during the penetration into the surface of the test body both in the X direction and in the Y direction—i.e. in the plane of the surface of the test body.

The measuring device for measuring the travelling movement of the penetration body along the Z axis, in particular the depth of penetration, and the at least one further measuring device for detecting at least one displacement of the penetration body along the travel path of the test body, are preferably provided in a housing portion of the housing, said housing portion adjoining the pressure chamber. These are preferably arranged in a row along a longitudinal axis of the housing, whereby the first and at least one further measuring apparatus can detect measuring signals directly during a penetration movement of the penetration body, said penetration movement being controlled by the pressure chamber.

A holding element is provided on a lower housing portion of the housing and at a distance from the first pressure surface of the pressure chamber, said holding element accommodating the penetration body. The penetration body is thus accommodated in a defined position relative to the housing. The holding element is preferably formed as a pressure membrane which has at least freedom of movement in one degree of freedom in the Z axis. A rotation or angular movement during the penetration of the penetration body into the surface of the test body is thus avoided.

Furthermore, the holding element is preferably formed to be soft or flexible in its extension plane at least in the direction of the displacement of the penetration body along the travelling movement of the test body and rigid in a direction perpendicular thereto. Further measuring signals can thus be detected during the introduction of a crack or scratch into the surface, in order to detect, for example, the homogeneity of the coating, inclusions or similar.

The holding element is preferably orientated parallel to the first and second pressure surface. Thus, all components involved in the travelling movement of the penetration body are oriented in a uniform manner. Furthermore, tilting of the penetration body relative to the force introduction via the pressure chamber can take place without loss by means of the holding element which is arranged at a distance from the first and second pressure surfaces.

The first and/or second pressure surface and/or the holding element are preferably made of copper beryllium. This material is especially suitable because it is virtually without hysteresis. A direct, loss-free control of the penetration body is thus possible.

Furthermore, a transmission pin is preferably provided between the first pressure surface and the penetration body. This is preferably formed to be pressure-resistant. A constructively simple and lightweight design can thus be created. Additionally, a direct connection between the penetration body and the first pressure surface can be produced.

Advantageously, the transmission pin is fixedly linked to both the pressure surface and the penetration body and forms a rigid connection. The actuating force generated by the pressure chamber can in turn be directly transformed into a penetration movement of the penetration body.

The at least one measuring device for measuring the travel path of the penetration body, in particular the penetration movement, and the at least one further measuring device each have at least two sensor elements which are moveable relative to one another, wherein each one of the sensor elements is arranged in a stationary manner on the housing and the at least one further sensor element is arranged on the transmission pin. Thus, during a penetration movement, a travel path is detected to the same extent both from the first and further measuring device, because these are arranged in a row.

Furthermore, the first measuring device preferably operates according to the eddy current method. Here, it involves proven measuring devices with no after-effects, which can also be provided with a compact design. For example, a ferrite plate or a ferrite ring can be fastened as a moveable sensor element on the transmission pin and a pot coil can be fastened on a housing as a second stationary sensor element, preferably releasably, in particular by a screw connection.

The at least one further measuring device for detecting the at least one displacement of the penetration body preferably comprises, for example, a ferrite ring or a ferrite ring as a moveable sensor element, said ferrite ring being arranged on the transmission pin, as well as at least one first coil which is assigned to the ferrite ring, such that the measuring device likewise operates according to the eddy current method. A displacement of the penetration body in the X direction can thus be detected. For example, the measuring device can have two coils which are arranged offset by 180° relative to each other in order to detect a displacement of the penetration body or the transmission pin along the travelling direction of the test body. Alternatively, two coils can also be assigned to a ferrite ring, which are offset by 90° relative to each other, such that, firstly, a displacement of the transmission pin along the travel path of the test body—i.e. in the X direction—and secondly, in the Y direction—can be detected.

Furthermore, a pressure stamp is preferably provided on the first and/or second pressure surface, which is provided for accommodation of a further element. Thus, for example, a sensor element or a component of a sensor element, such as, for example, a pressure sensor, can be arranged on the second pressure surface. Preferably, the transmission pin can be exchangeably fixed on the further stamp which is assigned to the first pressure surface.

A further advantageous embodiment of the measuring device provides that the penetration body is arranged exchangeably on the transmission pin. Thus, during repeated measurements, a simple exchange can take place. Alternatively, only the penetration tip can be formed exchangeably on the penetration body. This not only has the advantage that a fast exchange is enabled in the event of deterioration, but also that, depending on different surfaces to be tested, a corresponding penetration point can be selected and used. For example, the penetration point can be made of diamond, corundum, topaz or quartz.

Pressurised air is preferably provided as the pressure medium.

The object of the invention is further solved by a measuring arrangement for detecting measurement signals during a travelling movement, in particular of a depth of penetration or a scanning movement, of a penetration body into a surface or on a surface of a test body, in which a measurement table for accommodation of the test body is provided on a base body or a base plate, as well as a handling apparatus, in particular a tripod, which accommodates a measuring device which is transferred via the handling device into a position for placing a penetration body onto the test body, wherein the travelling movement for penetration of the penetration body into the surface of the test body or the travelling movement for scanning the surface of the penetration body is controlled and carried out by a measuring device according to one or more of the features described above of the embodiments.

Furthermore, the measuring arrangement preferably accommodates an optical detection apparatus adjacent to the measuring device, which optically detects and evaluates the penetration point, the surface roughness or, when the scratch-resistance test is being carried out, the scratch which has been introduced. Here, the measurement table is preferably transportable between the measuring device and the optical detection apparatus. Alternatively, the measuring device and the optical detection apparatus can be transportable to the measurement table.

Furthermore, a travelling movement of the measurement table, in particular an axis along a travelling direction in the plane of the surface of the test body, is preferably controlled by the controller. Thus, a surface contour or a roughness of the surface during placing of the penetration body onto the surface of the test body, which forms a start position, and a subsequent controlled travelling movement, can be detected by this controller. This can also be carried out for a pre-scan of a scratch-resistance identification. Likewise, a penetration movement of the penetration body can be controlled, starting from the start position, during the travelling movement of the measurement table towards the penetration body, in order to form a scratch. A post-scan for a scratch resistance test can also be controlled, starting from the start position.

A pump and preferably a storage container are provided for controlling the measuring device, said pump delivering the pressure medium to the measuring device with a delivery line, wherein this pump and preferably a storage holder are arranged separately from the mutual base body of the measuring device in order to avoid registering vibrations at least on the measurement table, in particular on the test body.

The object of the invention is furthermore solved by a method for detecting measurement signals during a penetration movement of a penetration body into a surface of a test body with a measuring device or during a scanning movement of a penetration body on a surface of a test body, in which the test body is positioned on a measurement table and the measuring device is placed on the test body, by a penetration movement of the penetration body being controlled with a force generating apparatus which is supplied by a test pressure of a gaseous pressure medium for the penetration movement of the penetration body into the test body or for a scanning movement on the test body. This enables a cost-effective design of the force generating apparatus. Additionally, an exact control of the penetration body can be achieved because the force generating apparatus comprises a low mass and thus there is no additional deterioration due to an slowia of high masses.

Preferably, the force generating apparatus is supplied with an initial pressure before the placement onto the surface of the test body, the measuring device is moved towards the test body and during placement of the penetration body of the measuring device the travelling movement of the measuring device is stopped, the force generating apparatus is subsequently supplied with a test pressure and a penetration movement of the penetration body in the surface of the test body is detected with a first measuring device. An exact detection of a hardness of a surface can thus be identified, because, firstly, the penetration movement and secondly, the force applied by the test pressure, can be evaluated in an exactly detected manner in order to identify the hardness of the surface of the test body. The initial pressure with which the force generating apparatus is supplied during the feed movement of the measuring device until the placement onto the test body, can, for example, be the ambient pressure. Alternatively, an overpressure can be introduced relative to the ambient pressure. Thus, defined states can be created relative to the force measurement apparatus.

Preferably, a pressure chamber is used as a force generating apparatus for carrying out the method, and a penetration movement of the penetration body into the surface of the test body is controlled with a first pressure surface of the pressure chamber. Here, a second pressure surface opposite the first pressure surface is moved relative to a sensor, wherein the force acting on the penetration body by means of the pressure chamber is detected by the sensor. The penetration movement generated by the pressure chamber is detected with respect to the depth of penetration by means of a first measuring device. The hardness of the surface of the test body can thus be determined, depending on the selected penetration body, from the force acting on the penetration body, said force being identified by means of the sensor, and the depth of penetration which is detected by the measuring apparatus. A pneumatic hardness measuring device can thus be created.

For identifying a scratch resistance of the surface of the test body, the measurement table is preferably transported in a direction perpendicular to the penetration movement of the penetration body during the penetration movement of the penetration body with the test body which is applied thereto, and a scratch is introduced into the surface of the test body. Measurement signals with respect to the depth of penetration are detected by a first measuring apparatus, depending on the time and the travelling path. Furthermore, a displacement of a penetration body against the travelling direction of the measurement table is detected by means of a second measuring apparatus. The scratch resistance of a surface of the test body can be determined from these detected signals.

Furthermore, a displacement orientated perpendicular to the travelling movement can preferably additionally be detected by a further measuring device during the introduction of a scratch into the surface of the test body. An evaluation with respect to the surface of the test body can thus additionally be created and, in particular, a statement on the homogeneity of the material can be achieved.

Furthermore, the measuring device is preferably placed on the surface before the introduction of a scratch into the test body, transported in a direction perpendicular to the placement direction of the test body and the surface is scanned. Signals are thus detected by the first measuring device and saved as a pre-scratching profile. The path of the surface of the test body can be determined by a so-called pre-scan, such that this further parameter can be taken into account during the subsequent determining of the scratch-resistance.

Furthermore, it is provided that a so-called post-scan is carried out for identifying the scratch resistance. For this purpose, preferably, the measuring device is placed onto the scratch after the introduction of the scratch into the test body, and the penetration body is transported with the measuring device in a direction perpendicular to the penetration movement of the test body, i.e. guided along in the scratch, and the detected measurement signals are stored.

A further preferred embodiment of the method provides that the test pressure is kept constant in the force generating apparatus during the scanning movement of the penetration body. The penetration body can thus be guided along the surface of the test body under constant conditions, wherein the pressure chamber is then effectively formed as a rigid actuating member, such that the travelling movement acting on the penetration body is transmitted directly along the longitudinal axis of the housing due to the surface roughness and can be detected by at least one sensor element. The test pressure can be the ambient pressure or an overpressure with which the pressure chamber is supplied.

A measuring arrangement11is schematically depicted inFIG. 1. Such a measuring arrangement11can be provided for testing mechanical and/or physical properties of surfaces on test bodies14, such as, for example, films, layers, and/or coatings on objects. For example, the measuring arrangement11can be used as a hardness measuring apparatus in which a hardness measurement is carried out by penetration by means of a penetration body41of a measuring device12. Furthermore, this measuring arrangement11can be provided with the measuring device12for identifying a scratch resistance of a film, a layer or coating on objects. Here, for example, CVD or PVD coatings can be checked with respect to their scratch resistance. Further micro-scratches can likewise be detected or other deformation information can be detected and analysed from the surface. This measuring arrangement11likewise also enables a roughness measurement of a surface of the test body14, in particular with the measuring device12, without accompanying damage to the surface of the test body14. In this case, the penetration body41is placed on the surface of the test body14and transported along the surface for scanning the roughness of the surface of the test body14.

The measuring device11comprises a mutual base body16. This can preferably be formed from granite. A tripod17is provided on the base body16, which accommodates the measuring device12on a boom18. This tripod12comprises a drive motor19, by means of which the measuring device12can be transported from an initial position21depicted inFIG. 1into a test position22, in which the penetration body41rests on a test body14. For example, the drive motor19can drive the boom18for an up and down movement along a guide post23of the tripod12.

A measurement table25is furthermore provided on the base body16. This measurement table25has a measurement table receptacle26which can be moveably driven at least in the X direction according to arrow27. The test body14is laid on the measuring table26and fastened thereto.

The measuring arrangement11can furthermore comprise an optical detection apparatus29which can likewise be arranged on the tripod17or, advantageously, separated therefrom on a further tripod31. This optical detection apparatus29can be positioned adjacent to the measuring device12. The measurement table25or the measuring table receptacle26is thus designed to be transportable in such a manner that the test body14is transportable relative to the optical detection apparatus29after the introduction of a penetration point or a scratch into the surface of the test body14, so that the penetration point or the scratch which has been introduced can be optically detected in the surface of the test body14. Alternatively, a travelling movement of the measuring device12and the optical detection device29can be provided relative to the measurement table25.

Furthermore, the measurement arrangement11comprises a schematically depicted controller33which comprises a computing apparatus not depicted in more detail, a display device35and an input device36. The controller33is connected to the tripod17, the measuring device12and the measuring table25at least by signal lines. Preferably, the optical detection apparatus29and optionally the tripod31receiving the optical detection apparatus29is also attached thereto.

Furthermore, the measuring arrangement11has at least one pump38for controlling the measuring device12, through which a pressure medium is delivered to the measuring device12in order to control a penetration movement of the penetration body41of the measuring device12. This pump38is connected to the controller33with a signal line. Advantageously, the pump33can deliver the pressure medium to a storage container39, from which the pressure medium is delivered to the measuring device12via a delivery line40. Both the pump38and the storage container39are not arranged on the mutual base body16.

InFIG. 2, a perspective view of the measuring device12according to the invention is depicted.FIG. 3shows a view from below. InFIG. 4, a schematic sectional view of the measuring device12according toFIG. 2is depicted, to which more detailed reference is made, in particular, to the depiction of the structure.

This measuring device12has a force generating apparatus44by means of which a travelling movement, in particular penetration movement, of the penetration body41onto the surface of the test body14is controlled. This force generating apparatus44comprises a pressure chamber46which is integrated into a housing47. This housing47has a cylindrical housing wall48to which a first pressure surface51and a second pressure surface52is assigned. These two pressure surface51,52are advantageously fixed to the housing wall48by a releasable connection, in particular a clamp connection or screw connection. The pressure chamber46is formed by the housing wall48and the first and second pressure surfaces51,52. Alternatively, a closed pressure chamber with terminals arranged thereon can be used. An inlet opening54and an outlet opening55are provided on the housing wall48, such that the pressure medium can be delivered and discharged.

An inlet control valve56is preferably provided in the delivery line40leading to the inlet opening54. Alternatively, the inlet valve56is directly attached to the inlet opening. An outlet control valve60is arranged in a further delivery line58on the outlet side for outflow of the pressure medium from the pressure chamber46. This can also be directly attached to the outlet opening55.

The first and second pressure surfaces51,52are preferably formed as a pressure membrane, in particular undulated pressure motors having preferably circular waves, which have one degree of freedom only in one direction, said degree of freedom being orientated in the Z direction and being on a longitudinal central axis61of the measuring device12. A rotation of the pressure surfaces51,52around the Z axis is prevented by the fixed clamping of the first and second pressure surfaces51,52to the housing wall48.

A pressure stamp63is fixedly arranged on each of the first and second pressure surfaces51,52. A sensor66assigned to the second pressure surface52can be fastened, for example, via a connection element64. The sensor66is formed, in particular, as a pressure sensor which detects the pressure located in the pressure chamber46depending on the movement of the second pressure surface52, and conveys it to the controller33.

A transfer pin68is provided between the first pressure surface51and the penetration body41, said transfer pin extending through a housing portion69which adjoins the housing wall47. This housing portion69is formed to be cylindrical, such that a first measuring device71for detecting a travelling movement of the penetration body41is detected therein. Furthermore, a further measuring device73is preferably arranged in the housing portion69, which detects at least one displacement of the penetration body41in the X direction during a penetration into the surface of the test body and preferably detects a simultaneous travelling movement of the test body14in the X direction. Furthermore, the at least one further measuring device73can also detect a displacement of the penetration body in the Y direction.

A holding element57is also provided on the lower housing portion69, which receives the penetration body41and extends up to an outer edge region76on the housing portion69. This holding element75can in turn be fastened to the housing portion69with a releasable connection. The holding element75is formed as a pressure membrane which has one degree of freedom in at least one movement direction. This at least one degree of freedom is in the Z axis or in the longitudinal central axis61of the measuring device12. The holding element47is preferably provided with two longitudinal slots, as depicted inFIG. 3. The holding element75thus becomes soft in a direction parallel to the longitudinal slots, which correspond to the X axis, and rigid in a Y axis. Because the holding device75is formed as a pressure medium, this holding device has a very low flexibility and is preferably not formed to be pressure-resistant in the X and Y direction.

The penetration body41is fastened exchangeably on the lower end of the transmission pin68. The penetration body41has a penetration tip78which can be releasably fastened on the penetration body41.

The housing portion69has a shoulder81which forms a through bore82through which the transmission pin68extends. A first sensor element84of the first measuring device71is fixedly arranged on the shoulder81and a second sensor element85of the first measuring apparatus71is arranged adjacently thereto on the transmission pin68. For example, the first and second sensor element84,85are formed as a distance sensor, wherein the first sensor element84comprises a pot magnet having a coil and the second sensor element85is a disc made of a ferritic material which is fastened to the transmission pin68. This second sensor element85is preferably releasable on the transmission pin68and adjustable in its distance from the first sensor element84, such that an alignment of the penetration body41in an initial position is possible. The measuring device71operates according to the eddy current principle.

The further measuring device73comprises a first sensor element88arranged on a holder87, which is provided to be fixed in place or housing-fixed, as well as a second sensor element89which in turn engages the transmission pin68. According to a first embodiment, this second sensor element89can be formed as a ferrite ring, opposite to which is a coil that forms the first sensor element88. A deflection of the penetration body41in the X direction can thus be detected, which is generated during the introduction of the penetration point or the scratch through the surface onto the penetration body41and transmitted to the transmission pin68. In addition, a third sensor element90can also be provided in order to detect a deflection in the X direction, such that an improved statement on the deviation in the X direction can be identified by a comparison of the detected values to the first and third sensor element88,90. Alternatively, the third sensor element can also be arranged offset by 90°, such that the first sensor element88detects a deflection in the X direction and the third sensor element90detects a deflection in the Y direction.

FIG. 5shows a schematic arrangement of the individual components of the measuring arrangement11, which are connected to the controller33via control lines. Using this schematic depiction, a method for carrying out a hardness measurement and a method for determining the scratch resistance of the surface of a test body14is discussed in the following.

For the hardness measurement of a surface of the test body14, the test body14according toFIG. 5is positioned and fixed on a measurement table receptacle26of the measurement table25. The force generating apparatus44is supplied with an initial pressure. For example, the pressure chamber46can be provided with an ambient pressure. This is achieved by the control valve60being opened and the control valve56being closed. Subsequently, the measuring device12is moved towards the surface of the test body14along the Z axis, for example by means of the motor19of the tripod17. As soon as the penetration body41is seated on the surface of the test body14, a signal is detected by the first measuring device71, due to a merely slight longitudinal movement or plunging movement of the penetration body41relative to the housing47of the measuring device12along the Z axis, and the lowering movement of the measuring device12along the Z axis is stopped. Here, the plunging movement of the penetration body41can be transmitted to the transmission pin68, whereby the first sensor element84opposite the second sensor element85is removed from the first measuring apparatus and thus emits a measuring signal.

Starting from this start position for the hardness measurement, in which the penetration body41rests on the surface of the test body, the outlet control valve60is closed and the inlet control valve56is opened, such that the pressure chamber46is supplied with a test pressure. This pressure of the in-flowing pressure medium, said pressure being present in the inlet opening54, is detected with a pressure sensor49and is conveyed to the controller33. The build-up of the pressure in the pressure chamber can take place directly by means of the pump38or be provided by the pump38or by the container receptacle39and regulated by the inlet control valve56.

During the build-up of the test pressure in the pressure chamber46, the first and second pressure surfaces51,52are displaced. The first pressure surface51causes a penetration movement of the penetration body51into the test body14. The second pressure surface52is moved in the direction of the sensor66by means of the test pressure. The displacement of the second pressure surface52is determined, firstly, by the test pressure, wherein a spring constant of the material of the second pressure surface52proportionally counteracts this pressure. The sensor66detects a change in distance from the second pressure surface52, from which the test pressure acting on the penetration body41is determined, due to the detected test pressure of the spring constant of the second pressure surface52and the distance from the second pressure surface52, said distance being detected by the pressure sensor66.

Due to the detected measuring signals of the first measuring device71with respect to the penetration movement and the actual identified test force, the hardness of the surface of the test body14can be determined. The shape or geometry of the penetration body41is also included in determining the hardness of the surface. For example, the penetration body41can be pyramid-shaped. This penetration body can consist, in particular, of diamond, corundum, topaz or quartz.

After the penetration movement of the penetration body41is ended, for example, the measuring device12can be raised from the test body14and the outlet control valve60can subsequently be opened. The outlet control valve60can likewise be opened firstly and then the measuring device12raised, or both can take place simultaneously.

On the transmission pin68and assigned thereto on a housing portion, the measuring device12has a second or further measuring device73. During the penetration movement of the penetration body41into the test body14, displacement movements which are taking place in the plane of the surface of the test body14—i.e. in the XY direction—can thus likewise be detected and taken into account as further assessment parameters.

Subsequently, after the introduction of a penetration point in the test body14, an illustration of the penetration point can be identified with the optical detection apparatus29and an optical evaluation can also be carried out.

The test body14is positioned on a measurement table25or on a measurement table receptacle26of the measurement table25for identifying the scratch-resistance of a surface of a test body14. The measuring device12is positioned above the test body14, such that a penetration body41can be moved towards this test body by means of a feed movement perpendicular to the surface of the test body14. The pressure chamber46of the measuring device12is supplied with an initial pressure. This initial pressure can be an ambient pressure which is adjusted, for example, by the inlet control valve56being closed and the outlet control valve60being open. The penetration body51is located in a rest position or off position in which it is positioned by the first pressure surface51of the pressure chamber46and by the holding element75. The initial position of the measuring device12relative to the test body14is depicted inFIG. 5.

The measuring device12is subsequently moved towards the test body14. This takes place, for example, by means of the motor19. As soon as the placement of the penetration body41on the surface of the test body14has been detected by the first measuring device71, the motor19is stopped. The measuring device12is arranged in a start position relative to the test body14. This start position can be provided for a so-called pre-scan for identifying the scratch-resistance. This start position can also be provided for a measurement of the surface roughness of the surface of the test body.

Starting from this start position, a so-called pre-scan can firstly be carried out, i.e., the surface of the test body14is scanned along a pre-determined travelling route of the penetration body41. This travelling route is orientated tangential or perpendicular to the test body14and, for example, along the X axis. The measuring device12preferably stops, and the measurement table25is transported by a motor28in the arrow direction27according toFIG. 4, whereby the position of the surface and the contour of the surface are scanned and the measured signals are saved as pre-scratch profile data, also known as pre-scan. Subsequently, the measuring device12is raised from the test body14. The measuring device12and the measuring table25are positioned in the start position again. Subsequently, the same travelling movement as in the pre-scan according to arrow27is in turn driven by the controller33by means of the motor28. At the same time as this travelling movement, the pressure chamber46is supplied with a test pressure, whereby the penetration body41penetrates increasingly into the surface of the test body14during the travelling movement of the measurement table25. This penetration movement is detected by the first measuring device71. Simultaneously, the actual pressure prevailing during the travelling movement is detected via the sensor66. Additionally, a displacement of the penetration body44in the direction of arrow27—i.e. in the travel direction—is detected by means of the further measuring device73, in particular the by first and second sensor element88,89, via the controller33. At the end of the pre-determined travelling movement, after application of the pre-determined test force, the measuring device14is in turn raised from the test body12. The measuring signals detected during the introduction of the scratch93(FIG. 4) are stored and evaluated by the controller33in order to determine the scratch-resistance.

The measuring device12and the measurement table25can be returned to the start position again after the introduction of the scratch93into the test body14. A post-scan can take place subsequently. The penetration body41is positioned in the scratch93. In turn, a travelling movement of the measuring table25according to arrow27takes place, whereby the penetration body41is guided along the scratch93. The measuring signals are detected again by the first measuring device71and the further measuring device73and/or the sensor66during the travelling movement of the penetration body41into the scratch93.

Additionally, a displacement of the penetration body41in the Y direction can be detected during the pre-scan, the introduction of the scratch93and/or the post-scan by means of a third sensor90of the further measuring apparatus73. Alternatively, this third sensor element90can also detect a deflection in the X direction in addition to the first sensor element88.

The optical detection apparatus29can detect the scratch and additionally enable an optical evaluation after the introduction of the scratch93and/or after the post-scan.

Starting from the above-mentioned start position in which the penetration body41is placed on the surface of the test body14, the measurement of the surface roughness can be carried out. The penetration body41is moved along a pre-determined travelling route on the surface of the test body14. This travelling route is orientated tangentially or perpendicular to the test body14and, for example, along the X axis. The measuring device12can thus stop, and the measurement table25is —as depicted inFIG. 4—transported by a motor28in the arrow direction27. Alternatively, the measurement table25can also stop and the measuring device12can be transported. A relative movement of measurement table25and measuring device12is likewise possible. The travelling movement of the penetration body41along the longitudinal axis of the housing47or the Z axis, said travelling movement being generated by the roughness of the test body14, is transmitted by the transmission pin48and the pressure chamber46, whereby a path change between the second pressure surface52and the sensor66is detected and evaluated by means of the controller33. After the scanning of a pre-determined travelling route along the surface of the test body14, the measuring device12is raised again by the test body14.