Measuring device

Abstract

Measuring device (10) for measuring the distance and / or speed of an object moving relative to the measuring device (10), comprising a measuring unit (12) comprising a measuring wheel (14) with a running surface (16) for placing on the object, and a holding unit (20) for attaching the measuring unit (12) to a stationary component, wherein the holding unit (20) has a holding arm (22) and an axle element (30), wherein the measuring unit (12) is arranged on the holding arm (22) and the axle element (30) is rotatably mounted on the holding arm (22) at a distance from the measuring unit (12), wherein a spring element (40) is attached to and / or in the axle element (30) transversely to the axis (32) of the axle element (30) in a rotationally fixed manner to the axle element (30), which extends further along the holding arm (22) in the direction of the measuring unit (12) and is fixed at least at one point along this extension on the holding arm (22), characterized by that the holding unit (20) has a fastening element (70) and a connecting adapter (50), wherein the axle element (30) is rotationally fixed to the connecting adapter (50), wherein the fastening element (70) can be fixed to the stationary component and the connecting adapter (50) is mounted in a guide of the fastening element (70) so as to be rotationally fixed and displaceable for movement between a mounting position (80) and a measuring position (90), wherein, by means of a relative rotation of the axle element (30) to the holding arm (22) compared to the mounting position (80) in the measuring position (90), the spring element (40) exerts a contact force (42) on the holding arm (22), which presses the measuring wheel (14) against the object.

Description

[0001] The invention relates to a measuring device for measuring the displacement and / or velocity of an object moving relative to the measuring device, comprising a measuring unit with a measuring wheel having a running surface for contact with the object, and a holding unit for attaching the measuring unit to a stationary component. The holding unit comprises a holding arm and an axle element, wherein the measuring unit is arranged on the holding arm and the axle element is rotatably mounted on the holding arm at a distance from the measuring unit. A spring element is attached to and / or in the axle element transversely to the axis of the axle element and is rotationally fixed to the axle element. The spring element extends further along the holding arm in the direction of the measuring unit and is fixed to the holding arm at least at one point along this extension. The present disclosure further relates to a method for mounting such a measuring device on a stationary component.

[0002] The measuring devices according to the invention are used in the automation industry to determine the path and / or speed of an object, for example a conveyor belt, wherein the conveyor belt moves relative to the measuring device. For this purpose, the measuring device is attached to a component that is stationary relative to the conveyor belt or to each object to be measured.

[0003] Such measuring devices typically comprise a measuring wheel with a preferably rubberized, knurled, or similarly treated running surface, which is attached to the shaft of a rotary encoder. The preferably rubberized, knurled, or similarly treated running surface of the measuring wheel is frictionally engaged with the object, particularly its surface, for example, a conveyor belt. The movement of the object causes the measuring wheel of the measuring device to move along with it, so that the rotation of the measuring wheel is transmitted via the shaft to the rotary encoder with precise angular accuracy. The encoder can then determine the position and / or speed of the measuring wheel and thus of the object, for example, the conveyor belt.

[0004] To obtain an accurate measurement of the distance and / or speed, slip-free contact between the conveyor belt and the measuring wheel is required. For this purpose, a holding unit is usually provided to attach the measuring device to the stationary component. This unit is attached and fixed to the stationary component and simultaneously presses the measuring wheel against the surface of the conveyor belt with a preferably predetermined force. This ensures slip-free measurement. The necessary force is often provided by a spring element.

[0005] In known assembly procedures for these measuring devices, for example, a gauge can be positioned between the measuring wheel and the surface of the object, and the holding unit can be pre-tensioned such that, after fixing the measuring device to the stationary component and removing the gauge, the spring element exhibits the specified force. However, this briefly overstretches an existing spring element during assembly. Furthermore, precautions are often necessary to prevent damage to the spring element or excessive pre-tensioning of the spring element.

[0006] Alternatively, it is also known to manually adjust the preload, particularly by adjusting the internal rotation of the spring element within the holding unit, thus controlling the force required to press the measuring unit against the object. However, this represents an additional effort during the assembly of the measuring device. Furthermore, operator errors can occur, resulting in inaccurate or, in the worst case, unusable measurements.

[0007] The object of the present invention is to improve upon the prior art described above. In particular, the object of the present invention is to provide a measuring device that enables simple and, in particular, operator-error-protected mounting of the measuring device in a measuring position on an object.

[0008] The problem is solved according to the invention by a measuring device according to independent claim 1. Further developments of the measuring device according to the invention are described in the dependent claims, the description, and the drawings. Features and advantages described in relation to the measuring device according to the invention also apply to the method disclosed herein, and vice versa.

[0009] According to the invention, the problem is solved by a measuring device for measuring the distance and / or speed of an object moving relative to the measuring device, comprising a measuring unit comprising a measuring wheel with a running surface for contact with the object, and a holding unit for attaching the measuring unit to a stationary component. wherein the holding unit has a holding arm and an axle element, wherein the measuring unit is arranged on the holding arm and the axle element is rotatably mounted on the holding arm at a distance from the measuring unit, wherein a spring element is attached to and / or in the axle element transversely to the axis of the axle element in a rotationally fixed manner to the axle element, which extends further along the holding arm in the direction of the measuring unit and is fixed at least at one point along this extension on the holding arm.The measuring device according to the invention is characterized in that the holding unit has a fastening element and a connecting adapter, wherein the axle element is rotationally fixed to the connecting adapter, wherein the fastening element can further be fixed to the stationary component and the connecting adapter is mounted in a guide of the fastening element so as to be rotationally fixed and displaceable for movement between a mounting position and a measuring position, wherein, by means of a relative rotation of the axle element to the holding arm in the measuring position compared to the mounting position, the spring element exerts a clamping force on the holding arm, which presses the measuring wheel against the object.

[0010] In short, with the connecting adapter in its mounting position, the measuring wheel can be placed with its running surface on the object to mount the measuring device according to the invention. The connecting adapter is then pressed towards the object, causing it to move along the guide in that direction. Due to the measuring wheel already being in contact with the object, the section of the retaining arm connected to the axle element is automatically pivoted relative to the section of the retaining arm connected to the measuring device as the connecting adapter is moved from the mounting position to the measuring position. Because of the rotationally fixed connection between the connecting adapter and the axle element, pressing down on the connecting adapter tensions the spring element, which is fixed at one end to the axle element and at the opposite end to the retaining arm. This creates a contact force for the measuring wheel against the object.In this way, the clamping force can be created with a simple movement during the assembly of the measuring device. A stop, which will be explained in more detail later, allows the device to be pressed down precisely to the stop, thus generating a predefined clamping force without additional aids or tools.

[0011] Further details of the measuring device according to the invention are described below.

[0012] The measuring device according to the invention is designed for measuring the distance and / or speed of an object moving relative to the measuring device. Such an object can, for example, be a conveyor belt. For this purpose, the measuring device has a measuring wheel with a running surface which, for example, may preferably be rubberized, knurled, or similarly prepared to ensure slip-free contact with the object's surface.

[0013] A mounting unit for the measuring device enables the entire measuring device to be attached near and / or to the object being measured. In particular, the mounting unit allows the measuring device to be attached to a stationary component, such as a housing or an internal structural element of the object.

[0014] This attachment to the stationary component enables a contact arrangement or positioning of the measuring unit, in particular the running surface of the measuring wheel, on a surface of the object. The measuring unit and, spaced apart from it, an axle element are arranged on a support arm of the holding unit, preferably on two opposing end sections of the support arm. Via the axle element, which is rotatably mounted in and / or through the support arm, the support arm is at least indirectly connected to a fastening element, which, as already explained above, serves to attach the entire measuring device to a stationary component.

[0015] A spring element is arranged on and / or within the axle element, fixed against rotation. Within the holding unit, the spring element extends from the axle element along the holding arm towards the measuring unit. Along this extension, the spring element is fixed to the holding arm at at least one point, for example, by positive locking via projections on the holding arm and / or by clips and / or screws. This at least one point of fixation is preferably located on the holding arm closer to the measuring unit than on the axle element, particularly in the last quarter or even more preferably in the last tenth of the spring element's extension towards the measuring unit.

[0016] The pivoting bearing of the axle element allows the holding arm to be swivelled around the axis defined by the axle element. The axle element itself does not rotate, or only minimally, during such a swivelling motion. This causes the spring element to deflect, as it is fixed to the axle element in a rotationally rigid manner (both on and / or within it) and also fixed to the holding arm. The force generated by this deflection is used to press the measuring unit, particularly its measuring wheel, located on the holding arm against the object.

[0017] In order to ensure the slip-free contact between the object and the measuring wheel required for an accurate measurement of the object's path and / or speed in a repeatable and adjustable manner, the measuring device according to the invention further provides a fastening element and a connecting adapter as elements of the holding unit.

[0018] The connecting adapter is rotationally fixed to the axle element. In other words, the connecting adapter and the axle element form a unit that can be moved together, for example, translated, and can also be rotated together.

[0019] The fastening element is, in particular, the part of the holding unit that serves to actually attach the measuring device to the stationary component. For this purpose, the fastening element has appropriately shaped fastening features, such as threads, holes, and / or bores for screws.

[0020] Furthermore, the fastening element has a guide in which the connecting adapter is mounted so as to be rotatably displaceable between a mounting position and a measuring position. Thus, the relative position of the connecting adapter to the fastening element can be changed, while the rotational position or angle of rotation of the connecting adapter, and therefore also of the axle element to which the connecting adapter is rotatably connected, remains unchanged.

[0021] The mounting position is further away from the object than the measuring position. Moving the connecting adapter from the mounting position to the measuring position therefore causes a movement towards the object. Via the axis element connected to the connecting adapter, the holding arm, and thus in particular the measuring unit, is automatically moved towards the object. The mounting and measuring positions are preferably chosen such that the measuring wheel of the measuring unit makes contact with the object at the latest during this movement. From this point onwards, for the remaining distance of the connecting adapter's movement to the measuring position, the holding arm pivots around the axis element, since the axis element is connected to the connecting adapter, but the holding arm can no longer fully follow this movement due to the measuring unit's contact with the object.

[0022] This automatically results in a relative rotation of the axis element to the holding arm in the measuring position. This causes the spring element, which is both rotationally fixed to the axis element and simultaneously fixed to the holding arm, to deflect. This deflection, in turn, generates a force that acts in the opposite direction. Since the deflection is primarily caused by the contact of the measuring wheel of the measuring unit against the object, a contact force is generated that presses the measuring wheel against the object.

[0023] As described above, generating and adjusting the contact force requires only moving the device, in particular the connecting adapter, from the mounting position to the measuring position. Time-consuming calibrations, for example with gauges, or adjustment procedures on the measuring device to set the contact force can be avoided. By preferably pre-setting and thus predefining at least the measuring position, and preferably also the mounting position, the risk of operator error during the setup and installation of the measuring device according to the invention can be further reduced.

[0024] Furthermore, the measuring device according to the invention can be characterized in that a projection is provided on the axle element on a side facing away from the measuring unit, and a first stop is provided on the holding arm, wherein the relative rotation of the axle element relative to the holding arm, and thus the contact force, is limited by the projection abutting the first stop. As described above, the contact force is caused by a relative rotation of the axle element relative to the holding arm, since this deflects the spring element. A projection on the axle element follows this relative rotation; in other words, it also moves relative to the holding arm. However, a positive-locking abutment of the projection against a correspondingly positioned stop on the holding arm, which can be provided as an add-on part or integrally with the holding arm, prevents further movement of the projection and thus further rotation of the axle element relative to the holding arm.This limits the relative rotation, which in turn limits the resulting contact force. This prevents the measuring wheel from being pressed too firmly against the object.

[0025] Furthermore, the measuring device according to the invention can be designed such that the contact force is limited to a value between 10 N and 20 N, preferably to a value of 14 N. The set contact force should preferably fulfill two requirements. Firstly, slip-free contact between the object and the measuring wheel should be ensured; secondly, any influence on the object by the pressed measuring wheel should be minimized. Limiting the contact force to a value between 10 N and 20 N, preferably 14 N, has proven particularly suitable for fulfilling both requirements. A reproducible contact force of the same magnitude, especially 14 N, also makes it possible to compare measurements on different objects, since this ensures that the adjustable measurement parameters of the different measurements remain consistent.

[0026] According to one embodiment, the measuring device according to the invention can further be designed so that, in the measuring position, the projection of the axle element abuts the first stop. In other words, the positions of the projection and the stop, as well as the relative positioning and orientation of the elements of the holding unit, in particular the holding arm and the axle element, are designed to be coordinated with one another in such a way that the set, limited contact force is achieved and generated in the measuring position. This can further facilitate the provision of reproducible measuring conditions.

[0027] Additionally or alternatively, the measuring device according to the invention can also be designed such that the spring element is fastened in a through opening in the axle element, with a head section of the spring element forming the projection. The opening can, for example, be formed by a bore. By arranging a section of the spring element in a through opening of the axle element, the rotationally fixed arrangement of the spring element with respect to the axle element can be ensured particularly easily. The arrangement can include a positive-locking and / or force-locking fastening of the spring element, for example by screwing it in via appropriately provided threads. A material-locking fixation, for example by gluing, is also possible alternatively or additionally.A head section of the spring element can protrude from the through-opening on the side of the axle element facing away from the measuring unit, extending over an outer surface of the axle element and thereby forming the projection. An additional component for providing the projection is therefore no longer necessary. Thus, the design of the measuring device according to the invention can be simplified.

[0028] According to one embodiment of the measuring device according to the invention, the axle element and the connecting adapter can each have corresponding, radially asymmetrical, and positively interlocking axial contact surfaces for rotationally fixed connection. In other words, when the connecting adapter and the axle element are arranged together, the axial contact surfaces form a positive fit that extends parallel to the axle and is radially asymmetrical. This ensures a rotationally fixed connection between these two elements. Perpendicular to the axle, the contact surfaces can, for example, have an elliptical shape or a circular shape in which at least one, and in particular two, opposing linear sections are inserted.

[0029] Furthermore, the measuring device according to the invention can be characterized in that the fastening element for slidably mounting the connecting adapter has a linear guide device. This allows the sliding movement from the mounting position to the measuring position to be provided as a simple, straight, and linear translation. This is a particularly simple movement, which further simplifies the handling of the measuring device according to the invention during installation.

[0030] According to one embodiment, the measuring device according to the invention can further be provided that the linear guide includes an elongated hole in the fastening element, preferably formed by an elongated hole in the fastening element. An elongated hole represents a mechanically particularly simple and, in particular, also uncomplicated type of linear guide or guide device. The complexity of the measuring device according to the invention can thus be further reduced.

[0031] The measuring device according to the invention can also be designed such that two axial guide lugs, arranged symmetrically to the axis, are provided on the connecting adapter for engaging in the elongated hole of the fastening element. The two guide lugs are guided in the elongated hole. The radially symmetrical arrangement of the two guide lugs to the axis ensures that the axis is positioned between the two guide lugs. The axis also moves along and at the level of the elongated hole. In addition to positioning the axis, the two guide lugs also ensure, in particular, the rotationally fixed guidance of the connecting adapter by the fastening element.

[0032] According to one embodiment of the measuring device according to the invention, the guide lugs can further be formed by screws that engage in corresponding threaded receptacles arranged in the connecting adapter, whereby the connecting adapter can be fixed to the fastening element, at least in the measuring position, by tightening the screws. The use of screws screwed into threaded holes avoids the need to mold complex protruding elements onto the connecting adapter, for example, through machining and / or a casting or deep-drawing process. This simplifies the overall manufacturing of the measuring device according to the invention. Furthermore, these screws enable the connecting adapter to be fixed to the fastening element, at least in the measuring position.Since the holding arm, and consequently the measuring unit with its measuring wheel, are firmly connected to the connecting adapter, the entire measuring device, especially the position of the measuring wheel and the contact force acting on it, can be fixed and secured. This enables reliable and consistent measurements using the measuring device according to the invention.

[0033] The measuring device according to the invention can also be designed such that the two guide lugs or the two threaded receptacles are provided on the connecting adapter in such a way that no relative rotation of the axle element with respect to the holding arm occurs in the mounting position. The mounting position represents the starting position for arranging the measuring device according to the invention on the object. By preventing a relative rotation of the axle element with respect to the holding arm in this mounting position, it is particularly ensured that no deflection of the spring element occurs in the mounting position and thus no force acts on the holding arm. Unnecessary stress on the spring element can thereby be avoided. This is particularly advantageous for embodiments of the measuring device according to the invention that are stored and / or delivered with a connecting adapter pre-assembled on the mounting element in the mounting position.

[0034] According to one embodiment, the measuring device according to the invention can be characterized in that the connecting adapter has two further threaded receptacles, wherein, relative to the existing threaded receptacles, the two further threaded receptacles are provided as mirror images on a plane perpendicular to the extent of the spring element in the mounting position in the connecting adapter, whereby screws which are screwed into the two further threaded receptacles form guide lugs that enable a mirrored arrangement of the measuring device with respect to the object. All features and advantages described above for the first pair of threaded receptacles can also be achieved for the mirrored arrangement of the measuring device on the object if screws are screwed into the second pair of threaded receptacles formed by the further threaded receptacles to form the guide lugs.The screws from the first pair of threaded mounts are preferably removed. This mirrored arrangement allows, for example, when measuring a conveyor belt, the measuring device to be repositioned to respond to a change in the conveyor belt's direction of travel. Alternatively or additionally, it can also be selected whether such a conveyor belt should be measured in the direction of travel towards or away from the measuring device.

[0035] According to one embodiment, the measuring device according to the invention can further be provided with a second stop on the holding arm, wherein, compared to the first stop, the second stop on the holding arm is mirrored along the extent of the spring element in the mounting position. This second stop offers the same advantages already described above for the first stop, only for the mirrored arrangement of the measuring device according to the invention with respect to the object to be measured. In particular, this second stop can limit the contact force, preferably to a value between 10 N and 20 N, and more specifically to a value of 14 N.

[0036] To mount a measuring device for measuring the distance and / or speed of an object moving relative to the measuring device according to the invention on a stationary component, a method disclosed herein can be used, which is characterized by the following steps: a) Attaching the fastening element to the stationary component, b) Arranging the connecting adapter with the holding arm and the measuring unit attached to it on the fastening element in its mounting position, c) Moving the connecting adapter along the preferably linear guide, in particular in the direction of the object, from the mounting position to the measuring position, and d) Fixing the connecting adapter in the measuring position on the mounting element.

[0037] This method is provided for mounting a measuring device according to the invention. All features and advantages described by a measuring device according to the invention can therefore also be achieved by the method disclosed herein.

[0038] In a first step a) of the method, the fastening element is attached to the stationary component. This can be done, for example, by screwing, clipping, or similar means to the stationary component. This fastening is preferably carried out in a position close to the object to be measured, so that the measuring wheel of the measuring unit of the measuring device according to the invention can reliably perform the intended measurement after assembly.

[0039] In the next step b), the connecting adapter, together with the support arm already attached to it and the measuring unit mounted thereon, is positioned in its assembly position on the fastening element. Since the measuring unit is already arranged on the support arm, and the support arm is connected to the connecting adapter via the axle element, after completion of step b), the entire measuring device according to the invention is arranged on the stationary component near the object to be measured.

[0040] In the following step c), the connecting adapter is moved along the preferably linear guide in the fastening element into the measuring position. The measuring position is preferably closer to the object compared to the mounting position. As already explained above, the use of the measuring device according to the invention results in a relative rotation of the axle element, which is non-rotatably connected to the connecting adapter, relative to the holding arm, which in turn causes a deflection of the spring element. This generates a preferably defined contact force that presses the measuring wheel against a surface of the object to be measured. The intended measurement can thus be carried out.

[0041] To ensure that the connecting adapter, and thus the entire measuring device, remains in the measuring position, the connecting adapter, and therefore the axis element, the holding arm, and in particular the measuring unit, is fixed in the measuring position in the final step d) of the procedure. Where applicable, this can preferably be done by tightening screws that are already present, for example, to provide guide lugs on the connecting adapter.

[0042] Furthermore, the method can be characterized in that step b) is performed before step a). In other words, the measuring device according to the invention can be pre-assembled, that is, with a connecting adapter already arranged on the fastening element, which in turn is connected via the axle element to the holding arm and the measuring unit arranged thereon. The entire pre-assembled measuring device can be attached to the stationary component via the fastening element.

[0043] In the following, embodiments of the measuring device according to the invention are described by way of example with reference to the figures. The figures show in detail Fig. 1 an exploded view of a first embodiment of the measuring device according to the invention in a first perspective, Fig. 2 the exploded view of the Fig. 1 in a second perspective, Fig. 3 the Fig. 1 first embodiment shown in a perspective view, and Fig. 4 a view of a second embodiment of the measuring device according to the invention.

[0044] The Fig. 1, Fig. 2 and Fig. Figure 3 shows a first embodiment of the measuring device 10 according to the invention, wherein the Fig. 1, Fig. Two views of an exploded diagram from different angles and Fig. Figure 3 shows a perspective view of an assembled measuring device 10. The three figures are described together below.

[0045] A measuring device according to the invention particularly comprises a measuring unit 12 with a measuring wheel 14, the running surface 16 of which is used to measure the distance or speed of an object moving relative to the measuring device 10, for example a conveyor belt (not shown). For this purpose, the running surface 16 of the measuring wheel 14 should advantageously be provided with a defined contact force 42 (see figure). Fig. 4) are pressed against a surface of the object to ensure slip-free contact and thus error-free measurement. According to the invention, the illustrated measuring device 10 has a holding unit 20 for this purpose.

[0046] The holding unit 20 has, in particular, a holding arm 22 on which, as shown, the measuring unit 12 is arranged in an end section. An axle element 30 is also connected to the holding arm 22 and is rotatably mounted in the holding arm 22 about its axis 32, in the illustrated embodiment also in an end section opposite the end section with the measuring unit 12. In other words, the holding arm 22 is also pivotable about the axis 32 due to the rotatable mounting of the axle element 30.

[0047] Furthermore, a spring element 40 is provided which, as shown, is attached transversely, and in particular perpendicularly, to the axis 23 in a through opening 36 of the axle element 30. The spring element 40 extends further along the retaining arm 22 and is fixed to the retaining arm 22, particularly near the measuring unit 12, in the illustrated embodiment by a positive-locking clamping of the end of the spring element 40 facing the measuring unit 12. This ensures that when the retaining arm 22 pivots relative to the axle element 30, the spring element 40 is deflected, since it is both rotationally fixed to the axle element 30 in the opening 36 and also fixed to the retaining arm 22. As explained below, this can be used for the controlled and reproducible generation of a contact force 42 (see Figure 1). Fig. 4).

[0048] Furthermore, the holding unit 20 of the measuring device 10 according to the invention comprises a fastening element 70 and a connecting adapter 50. The fastening element 70 is specifically designed for attachment to a stationary component (not shown) and, for this purpose, has corresponding fastening devices, such as the clearly visible H-shaped recess in the illustrated embodiment. The connecting adapter 50, in turn, provides a connection between the fastening element 70 and the axle element 30 or the holding arm 22.

[0049] In particular, the measuring device 10 according to the invention is provided in such a way that the connecting adapter 50 and the axle element 30 are arranged in a rotationally fixed manner relative to one another. This can be achieved, for example, as shown, by a positive-locking axial contact of non-radially symmetrical mutual contact surfaces 38, 52 on the axle element 30 and on the connecting adapter 50, wherein the two components are generally fixed to one another by a screw connection. Here, the contact surfaces 38 on the axle element 30 are particularly in Fig. 2, the contact surfaces 52 on the connecting adapter 50 in particular in Fig. Figure 1 shows. In other words, the axle element 30 and the connecting adapter 50 form a unit with respect to rotations.

[0050] Furthermore, it is provided that the connecting adapter 50 is guided in a rotationally fixed manner by the fastening element 70, in particular between a mounting position 80 ( Fig. 1, Fig. 2, Fig. 3) and a measuring position 90 ( Fig. 4) Rotationally fixed and movable means in particular that the position of the connecting adapter 50 changes translationally, but its rotational position remains unchanged.

[0051] In the illustrated embodiment, this is achieved by a linear guide element 72 of the fastening element 70, into which two guide lugs 54 of the connecting adapter 50, radially opposed with respect to the axis 32, engage. The guide element 72 can, as shown, preferably be formed by an elongated hole 74. Furthermore, screws 56 fastened in corresponding threaded receptacles 58 provided in the connecting element 50 can also preferably form the guide lugs 54.

[0052] If the connecting adapter 50 is now moved from the mounting position 80 towards the measuring position 90 (see below) Fig. 4) If the axle element 30 is displaced, this occurs purely translationally, without the connecting adapter 50 rotating. This also acts on the axle element 30 via the contact surfaces 52, 30. Overall, this displacement is also transmitted to the holding arm 22 and thus also to the measuring unit 12 via the bearing of the axle element 30. When the measuring wheel 14 now contacts the object to be measured, the end of the holding arm 22, on which the measuring unit 12 is arranged, can no longer follow the displacement; the holding arm 22 rotates relative to the axle element 30. The end of the spring element 40 fixed to the holding arm 22 is thus also deflected relative to the end of the spring element 40 attached to the axle element 30, thereby generating a contact force 42 that presses the running surface 16 of the measuring wheel 14 against the object to be measured (cf. Fig. 4).

[0053] To limit this contact force, provisions can be made in the measuring device 10 according to the invention. For example, as shown, the holding arm 22 can have a first stop 24 against which a projection 34 of the axle element 30 abuts during relative rotation. This prevents further relative rotation of these two elements, thereby also limiting the deflection of the spring element 40 and thus automatically the achievable contact force 42, preferably to values ​​between 10 N and 20 N, and in particular to a value of 14 N. The projection 34 on the axle element 30 can preferably be formed by a head section 44 of the spring element 40, which protrudes from the through opening 36 in the axle element 30.

[0054] Furthermore, as for example in Fig. As is clearly visible, the connecting adapter 50 has additional threaded receptacles 60, which allow the screws 56 to be repositioned. These additional threaded receptacles 60 are mirrored relative to the existing threaded receptacles 58 on a plane perpendicular to the extension of the spring element 40. This makes it possible to create modified guide lugs 54 simply by repositioning the screws 56, enabling a mirrored arrangement of the measuring device 10 with respect to the object. To also provide the above-described limitation of the contact force 42 for this mirrored arrangement, the holding arm 22 can have a correspondingly arranged second stop 26, as shown.

[0055] In summary, the measuring device 10 according to the invention enables particularly simple assembly, and in particular, the adjustment of the contact force 42 can be made especially easy and error-resistant. The following steps are carried out for the assembly of the measuring device 10, whereby the order of steps a) and b) can also be reversed: a) Attaching the fastening element 70 to the stationary component, b) Arranging the connecting adapter 50 with the retaining arm 22 and the measuring unit 12 arranged thereon on the fastening element 70 in its mounting position 80, c) Moving the connecting adapter 50 along the guide in the fastening element 70, in particular in the direction of the object, from the mounting position 80 to the measuring position 90, and d) Fixing the connecting adapter 50 in the measuring position 90 on the fastening element 70.

[0056] In particular, in step c) the contact force 42 is generated and adjusted, preferably automatically limited as described above by appropriate design of the measuring device 10 with a projection 34 on the axle element and a stop 24, 26 on the holding arm 22.

[0057] Fig. Figure 4 now shows an illustration of a further embodiment of the measuring device 10 according to the invention. From the one described in the Fig. The embodiment shown in Figures 1-3 differs essentially only in that the spring element 40 and the measuring wheel 14 are arranged on the same side of the retaining arm 22. Fig. However, 1-3 are on different pages. In the remaining features, the two embodiments largely agree, so that the fundamental properties of the one in Fig. 4 illustrated embodiment of the measuring device 10 according to the invention refers to the above description of the Fig. 1 - 3 are referred to.

[0058] The difference, however, is in Fig. Figure 4 shows the measuring device 10 in measuring position 90. It is clearly visible that the measuring wheel 14 rests on a surface with its running surface 16. However, what is shown is not an object to be measured, but merely a table surface for demonstration purposes.

[0059] Nevertheless, it is clearly visible that the spring element 40 is deflected, since one end, near the measuring unit, is fixed to the retaining arm 22, and its opposite end is rotationally fixed in the axle element 30. This deflection generates the contact force 42, which presses the running surface 16 of the measuring wheel 14 against the surface. Furthermore, it is also evident that the relative rotation of the axle element 30 with respect to the retaining arm 22 is limited by a positive-locking contact of the projection 34 formed by the head section 44 of the spring element 40 with the first stop 24 of the retaining arm 22. As shown, preferably the positioning of the projection 34 and the first stop 24 can be selected to match the relative rotation of the axle element 30 and the retaining arm 22 such that in the measuring position 90, the projection 34 abuts the first stop 24. Reference sign 10 Measuring device 12 Unit of measurement 14 measuring wheel 16 tread surface 20 Holding unit 22 Support arm 24 first attack 26 second attack 30 axle element 32-axis 34 lead 36 Opening 38 contact area 40 spring element 42 Contact force 44 Head section 50 connection adapters 52 contact area 54 Lead nose 56 screw 58 threaded mount 60 additional threaded inserts 70 Fastening element 72 Guide system 74 Slotted hole 80 Mounting position 90 measuring position

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