Connecting element, in particular arm, of a coordinate measuring machine and method for manufacturing a connecting element

Abstract

Connecting element (1), in particular arm, of a coordinate measuring machine, wherein the connecting element (1) comprises the following: - Connections (19, 20) at opposite end regions of the connecting element (1) with respect to a longitudinal direction for mounting the connecting element (1) to at least one other part of the coordinate measuring machine, - at least three longitudinal belts (2, 3, 4, 5) extending from one end area to the other end area along the longitudinal direction, - a plurality of diagonal braces (7 to 14), each extending along a direction oblique to the longitudinal direction from one of the longitudinal chords (2, 3, 4, 5) to another of the longitudinal chords (2, 3, 4, 5) and connecting them together, characterized in that at least one pair (7 and 11, 8 and 12; 9 and 11, 10 and 12) of the diagonal braces (7 to 14) is present, consisting of a first diagonal brace (7, 8; 9, 10) and a second diagonal brace (11, 12; 11, 12), which, viewed in a construction direction transverse to the longitudinal direction, are spaced apart from one another and are skew to each other, wherein the first diagonal brace (7, 8; 9, 10) and the second diagonal brace are connected by a straight line in the direction of the The additional strut (24, 25) running in the direction of construction are connected to each other.

Description

[0001] The invention relates to a connecting element, in particular an arm of a coordinate measuring machine, and a method for manufacturing such a connecting element. In particular, the invention also relates to a coordinate measuring machine with the connecting element and a method for manufacturing a coordinate measuring machine.

[0002] The term coordinate measuring machine (CMM) encompasses all types of devices used to determine the coordinates of workpieces. In one class of CMMs, the coordinates are surface coordinates, meaning the coordinates of surface points on workpieces are determined. The term CMM specifically includes classic CMMs, such as portal and gantry-type machines, and / or CMMs with a movable bridge, on which, in particular, a quill with a sensor that can move relative to the bridge is mounted, as well as articulated arm machines and machines with a hexapod mechanism. Furthermore, it includes machines in which at least one sensor is fixed with respect to at least one degree of freedom of the relative movement between the sensor and the workpiece, and in which the workpiece to be measured is movable relative to the at least one sensor, as in a machine with a movable measuring table.The term coordinate measuring machine also encompasses machines that, while not primarily designed as coordinate measuring machines, are configured to operate like one. In particular, these machines have at least one measuring sensor used to determine the coordinates. Examples include robots, such as robot arms with rotary joints, to which a sensor for detecting the workpiece surface (e.g., a fringe projection sensor) is attached instead of or in addition to a tool, or machine tools to which a measuring sensor (e.g., a tactile sensor) is attached instead of or in addition to a machining tool. Hexapod mechanisms are also known, to which a sensor for detecting the workpiece surface (e.g., a tactile sensor) is attached instead of a machining tool.

[0003] Person-operated (e.g., hand-held) coordinate measuring machines are also known, in which at least one sensor is mounted on a movable mechanism. In this case, there is no motor drive to generate the sensor's movement, or the motor drive assists the person's movement. Both scanning and scanning of the object being measured are possible, each from a fixed position with a fixed sensor orientation.

[0004] The invention is not limited with regard to the types of sensors used by a coordinate measuring machine to determine the coordinates. Tactile sensors have already been mentioned as an example; these can be, for instance, of the switching or measuring type. In particular, the tactile sensors can be passive or active. Active sensors can be designed to generate a probing force with which a tactile probe contacts the surface of a workpiece to be measured. Optical sensors are frequently used as an alternative or in addition. Furthermore, there are, for example, capacitive and inductive sensors.

[0005] In many cases, the sensor is movable relative to the base of the coordinate measuring machine. Especially in this case, but also when the sensor is stationary, it is essential to support it. This requires at least one connecting element of the coordinate measuring machine. Alternatively or additionally, other parts of the coordinate measuring machine can be connected to another part of the machine via a connecting element, whereby "connected" optionally also allows movement of the connecting element relative to at least one other connected part. In particular, the connecting element can therefore be articulated, i.e., connected to the respective other part via at least one joint. In a specific case, the connecting element is directly connected to the sensor via a port, or directly to a coupling device for attaching and / or holding the sensor.

[0006] The present invention relates in particular to a connecting element of one of the aforementioned coordinate measuring machines. For example, the coordinate measuring machine could be a SCARA robot. Such a measuring machine was offered, for example, by Carl Zeiss Industrial Metrology GmbH, Oberkochen, Germany, under the name ScanMax. The measuring machine has a stationary column with a vertically movable Z-carriage. A rocker arm is attached to this carriage by means of a pivot joint. At the front end of the rocker arm, another pivot joint with an arm attached to it is mounted. A sensor (e.g., tactile) is arranged at the front end of the arm. The connecting element according to the invention could, for example, be the aforementioned arm or a part of the rocker arm. In order to make such a connecting element rigid, i.e., dimensionally stable, while maintaining low weight, it can be assembled from several parts, e.g., welded or bonded.

[0007] WO 92 / 18 715 A1 discloses a spatial structure particularly suitable for use in high-precision coordinate measuring machines. Hollow frame components are described, which have unidirectional fibers lying parallel to the longitudinal axes of the respective components. Several of the components can be connected to each other at one end by a connector. An embodiment of a frame structure with such components is described in the Fig. 5 and Fig. Figure 6 shows components running diagonally with their longitudinal axis and components running in a longitudinal direction of a frame structure with their longitudinal axis, which are connected to each other via connectors.

[0008] US 6,202,316 B1 describes a structure for use in a coordinate measuring machine made of a composite material in which metallic material is bonded to non-metallic material. The spatial frame structure can be a modified I-strut.

[0009] DE 297 05 152 U1 relates to machining centers consisting of multiple columns, a pair of linear guides resting on the columns, a gantry movable in the X-direction on the linear guides, a crossbeam movable in the Y-direction on the gantry, and a quill held movable in the Z-direction by the crossbeam. A gantry design is disclosed as a prestressed lightweight strut frame. The figures show a construction with longitudinal chords and diagonal braces, which are not explained in detail in the description.

[0010] It is often desirable for components of coordinate measuring machines to be rigidly designed so that they do not change their shape, or only minimally, due to the forces exerted on them during operation. Particularly in cases where a sensor is connected to the base of the coordinate measuring machine via rigid components, any deformation of these components under load is therefore small or negligible. It is, of course, possible to take even a small deformation into account when determining the coordinates of a measured object, especially a workpiece, and to correct for it computationally.

[0011] It is therefore an object of the present invention to provide a connecting element for a coordinate measuring machine that exhibits high stiffness at low weight, in particular high stiffness with respect to a direction transverse to a longitudinal direction of the connecting element. In particular, the connecting element should preferably have no joints, i.e., be / be manufactured from a single piece. It is a further object of the present invention to provide a method for manufacturing such a connecting element. Furthermore, it is optionally additional objects of the present invention to provide a coordinate measuring machine with such a connecting element and a method for manufacturing such a coordinate measuring machine.

[0012] A connecting element (claim 1) and a method (claim 6) for its manufacture are proposed, the connecting element comprising at least three longitudinal chords extending from one end region to another. A plurality of diagonal braces extend along a direction oblique to the longitudinal direction from one of the longitudinal chords to another, connecting them together. In structural engineering terms, each of the diagonal braces preferably forms a truss with other parts of the connecting element, such as at least one longitudinal chord, another diagonal brace, and / or a connection in one of the end regions of the connecting element. Therefore, a truss-like structure can be described. In particular, at least one of the trusses can be triangular, with slight deviations from the triangular shape being permissible, especially in the area of ​​the connections.

[0013] The connecting element can be described in particular as a lightweight beam or truss girder. In particular, some embodiments of the truss girder can be described as box-shaped overall. Furthermore, the aforementioned webs and / or longitudinal chords can be rod-shaped components.

[0014] Longitudinal chords and diagonal braces preferably run not only along their respective directions, but in the direction of the longitudinal chord, and in this case, they run in a straight line for at least a portion of their length. "Along the direction" therefore means, in contrast to "in the direction of the longitudinal chord," that the component can also run in a different direction that deviates slightly from "the direction." An example is described below in which the distances between the various longitudinal chords decrease along the longitudinal direction.

[0015] The connecting element has terminals at its opposing ends for mounting it to at least one other part of the coordinate measuring machine. As mentioned, at least one of the terminals can be part of a joint. However, it is also possible that at least one of the terminals serves as a fixed connection to the respective other part of the coordinate measuring machine and is therefore not part of a joint. Regardless of whether the terminal forms a joint or not, in a simple case, at least one of the terminals could be, for example, a solid area of ​​material with or without recesses and / or cavities. Alternatively, it could be, for example, a joint component that, when interacting with a corresponding joint component, allows for rotational movement.Alternatively or additionally, the connection can, for example, include a guide for guiding the linear movement of a part mounted on it, or conversely, have a section that can interact with such a guide. Overall, however, the type of connection and thus the way the connecting element is attached to other parts of a coordinate measuring machine is not limited to specific designs.

[0016] It is proposed that: A connecting element, in particular an arm, of a coordinate measuring machine, wherein the connecting element has the following features: - Connections at opposite end regions of the connecting element with respect to a longitudinal direction for mounting the connecting element to at least one other part of the coordinate measuring machine, - at least three longitudinal belts extending from one end area to the other along the longitudinal direction, - a plurality of diagonal struts, each extending along a direction oblique to the longitudinal direction from one of the longitudinal chords to another of the longitudinal chords and connecting them together.

[0017] Furthermore, the following is proposed: A method for manufacturing a connecting element, in particular an arm, of a coordinate measuring machine, wherein connections of the connecting element are made on end regions of the connecting element that are opposite each other with respect to a longitudinal direction, in order to be able to mount the connecting element via the connections on at least one other part of the coordinate measuring machine, wherein the method further comprises: - Manufacturing at least three longitudinal belts such that the longitudinal belts extend from one end area to the other end area along the longitudinal direction, - Manufacturing a plurality of diagonal braces such that the diagonal braces each extend along a direction oblique to the longitudinal direction from one of the longitudinal chords to another of the longitudinal chords and connect them together.

[0018] Further features of the invention are described on page 9.

[0019] The combination of longitudinal chords with diagonal braces enables a lightweight yet rigid design. Weight and stiffness depend on the specific implementation of the construction. Furthermore, such a connecting element can be manufactured in one piece, for example by milling or casting.

[0020] In this description, an axis is understood to be a straight line fixed in space, running in a direction corresponding to that straight line. It follows that a direction does not have a fixed spatial position, and, for example, all parallel straight lines run in the same direction.

[0021] Preferably, viewed in the direction of a structural axis extending transversely and, in particular, perpendicular to the longitudinal direction, at least one of the diagonal braces and at least one of the longitudinal chords (e.g., exactly one of the longitudinal chords), which the at least one of the diagonal braces connects to another of the longitudinal chords, lie side by side. They run offset from each other such that the at least one of the diagonal braces runs in a first plane containing the structural axis, and the at least one of the longitudinal chords runs in a second plane parallel to the first plane. "Side by side" in the aforementioned viewing direction means that a cross-section of the diagonal brace and the longitudinal chord occupy adjacent and preferably abutting areas in a third plane extending perpendicular to the viewing direction and thus also perpendicular to the structural axis.Although the diagonal brace connects the longitudinal chord to another longitudinal chord, its diagonal course, oblique to the longitudinal direction, does not necessarily have to begin or end directly at the longitudinal chord. For example, the diagonal brace and the longitudinal chord can be connected via a particularly short intermediate section, such as if this intermediate section is located at the end of the connecting element. This intermediate section then does not run obliquely to the longitudinal direction in the same way as the diagonal brace.

[0022] As mentioned, the structural axis runs transversely and, in particular, perpendicular to the longitudinal direction. If the structural axis is not exactly perpendicular to the longitudinal direction, it may, for example, form an angle with the longitudinal direction of no more than 10 degrees, in particular no more than 5 degrees, and preferably no more than 2 degrees. The structural axis is an imaginary axis; that is, none of the struts and none of the chords need to contain the structural axis, although this is possible. As mentioned, however, the diagonal strut runs in a first plane that contains the structural axis. In particular, in the case of a connecting element that has four longitudinal chords arranged in the manner of the edges of a cuboid, the first plane may also run in the longitudinal direction.The first plane can therefore be described in particular as being spanned by the construction axis, which runs transversely (especially perpendicularly) to the longitudinal direction, and by a longitudinal axis running in the longitudinal direction. In this case, the second plane, in which the longitudinal chord runs, is spanned by another longitudinal axis running in the longitudinal direction and by a further axis running parallel to the construction axis.

[0023] This situation can also be expressed as follows: The diagonal brace and the longitudinal chord, which the diagonal brace connects to another longitudinal chord, are not aligned along the design axis. This allows a molded part, which is part of a mold for producing the connecting element, to be removed precisely along the design axis from the connecting element produced in the mold. This process is called demolding. The direction of the design axis can be referred to as the demolding direction. In particular, the mold can have at least two mold halves (especially the aforementioned molded part and another molded part). Preferably, as will be described in more detail below, the mold does not have cores or slides for producing the area with the diagonal brace and the longitudinal chord, i.e.,In particular, the central part of the connecting element, from one end to the other, can be manufactured exclusively using two mold halves. This does not preclude the connections of the connecting element from being manufactured using at least one additional mold part, although it is preferred that the entire connecting element be manufactured exclusively using two mold halves. Of course, post-processing can still take place after the connecting element has been demolded. "Exclusively using two mold halves" therefore refers to the process of manufacturing the connecting element with a single mold.

[0024] The manufacturing process for the fastener therefore preferably includes a mold casting step. In this process, the molten and / or flowable material for the fastener is poured into a mold, where it then solidifies and / or hardens. Typically, metals are used, with alloys of several metals often employed to manufacture the fastener. However, it is not excluded that at least one non-metallic material is added to the metallic material, or that the melt or liquid material poured into the mold consists predominantly of a material other than metal, or is completely metal-free.

[0025] Particularly in metal casting, the casting process can be sand casting, permanent mold casting, or die casting. Basically, any casting method suitable for manufacturing a connecting element for a coordinate measuring machine is an option. Preferably, it is a casting process in which the mold is not lost.

[0026] Regarding the manufacturing process, the connecting element can therefore be produced using a hollow mold, particularly in a casting process. For details, please refer to the manufacturing-related descriptions of the connecting element. In particular, when manufacturing the aforementioned area with the diagonal brace and the longitudinal chord, only two mold halves can be used, and cores or slides can be avoided in this area.

[0027] Preferably, a plurality of diagonal braces are present, connecting at least one of the longitudinal chords to another. In particular, several of the diagonal braces can run parallel to each other and connect the same longitudinal chord to the same other longitudinal chord. In this case, the multiple diagonal braces are arranged one behind the other in the longitudinal direction. Furthermore, along the length of the connecting element, from one end region to the other, diagonal braces can follow one another, connecting the same longitudinal chord to the same other longitudinal chord and alternating in a first inclined direction and a second inclined direction. As mentioned above, each inclined direction is understood to be a direction running obliquely to the longitudinal direction.Alternatively or additionally, at least one of the diagonal braces can connect a first longitudinal chord to a second longitudinal chord, and at least one of the diagonal braces can connect a third longitudinal chord to a fourth longitudinal chord. In this case, the at least one first and at least one second of the diagonal braces are located on opposite sides of the connecting element (viewed perpendicular to the longitudinal direction of the connecting element). Specifically, in the case of a total of four longitudinal chords, a group of diagonal braces arranged one behind the other in the longitudinal direction of the connecting element can be provided on each of the two opposite sides of the connecting element.In the case of a total of three longitudinal chords, at least one of the diagonal struts can connect a first longitudinal chord with a second longitudinal chord, and at least one of the diagonal struts can connect the first longitudinal chord with a third longitudinal chord.

[0028] With reference to the preceding paragraph, at least one group of diagonal struts lying one behind the other in the longitudinal direction, considered in the direction of a construction axis running perpendicular to the longitudinal direction, and a longitudinal chord associated with the group, which the diagonal struts of the group connect with the same other of the longitudinal chords, can lie side by side as described above.

[0029] According to the claims, at least one pair of diagonal braces is provided, consisting of a first diagonal brace and a second diagonal brace, which, viewed in a construction direction that runs transversely (and in particular perpendicularly) to the longitudinal direction, are spaced apart from one another and run at an angle to each other. The first diagonal brace and the second diagonal brace are connected to each other by an additional brace that runs straight and in the direction of the construction direction.The term "straight path" of the additional strut includes the case where, in the case of manufacturing the connecting element using a hollow mold, the additional strut tapers along the demolding direction and / or has at least a surface inclined to the demolding direction (for example, at an angle of no more than 3 degrees, in particular no more than 2 degrees, and for example, no more than 1 degree to the demolding direction). This also applies accordingly to the cross struts and / or cross supports described later.

[0030] The first and second diagonal braces are positioned one behind the other in a direction that runs perpendicular (and especially perpendicular) to the longitudinal direction, and they do not connect the same pair of longitudinal chords. For example, in the case of a total of four longitudinal chords, the first diagonal brace connects the first longitudinal chord to the second, and the second diagonal brace connects the third to the fourth. In the case of a total of three longitudinal chords, the first diagonal brace connects the first longitudinal chord to the second, and the second diagonal brace connects the first to the third. One advantage of this pairwise skew arrangement (as opposed to a parallel or substantially parallel arrangement of the diagonal braces) is that the overall structure can be made stiffer.A further advantage relates to the aforementioned, preferably present, additional strut that connects the first and second diagonal struts. This additional strut runs in a straight line in the design direction. If the connecting element also has the feature described above (at least one diagonal strut and longitudinal chord lying side by side in the viewing direction of the aforementioned design axis), then the direction of the design axis is also the design direction. In particular, the additional strut can therefore be easily produced by forming it in a cavity between the two mold halves mentioned above. Furthermore, the demolding direction is a direction in which the additional strut extends in a straight line from the first diagonal strut to the second diagonal strut.The demolding direction is the same for both mold halves, but the mold halves are demolded in opposite directions.

[0031] The spatial arrangement of the first and second diagonal braces therefore allows, at least in the area where the pair of diagonal braces is located or will be located, the use of only two mold halves. No cores or slides are required there. The mold halves can be easily demolded from the casting-produced connecting element in the straight line following the direction of the additional brace.

[0032] The additional strut therefore has the advantage of enabling simple manufacturing of the connecting element, at least in the area of ​​the diagonal strut pair, using only two mold halves. Furthermore, the additional strut increases the overall stiffness of the connecting element in the area of ​​the diagonal strut pair.

[0033] Preferably, the connecting element has several pairs of diagonal braces, each connected to the other by an additional brace. All these additional braces run parallel to each other in the same straight line. The number of pairs of diagonal braces, each with an additional brace, depends on the design of the overall construction of the connecting element, and in particular on the longitudinal length of the connecting element.

[0034] In particular, the aforementioned design direction runs transversely and preferably perpendicular to the longitudinal direction. However, depending on the overall design of the connecting element, the longitudinal direction can also be defined in different ways with respect to the same connecting element. This means that different directions, each forming a small angle with one another (for example, an angle of no more than 20 degrees, in particular no more than 10 degrees, and preferably no more than 5 degrees), can each be defined as the longitudinal direction. This applies particularly in the case where the multiple longitudinal flanges do not run parallel to one another. The accompanying figures, which will be described in more detail later, show an example of a tapered cross-section of the connecting element where this is the case.In particular, if the longitudinal chords are not parallel to each other, the longitudinal direction can be chosen such that at least one longitudinal segment of at least one of the longitudinal chords extends exactly in the longitudinal direction. However, if the longitudinal chords run parallel to each other in a straight line, it is more appropriate to define the longitudinal direction as the direction in which the longitudinal chords extend in a straight line.

[0035] Alternatively or additionally, in a structural direction that runs transversely and preferably perpendicular to the longitudinal direction, a section of one of the longitudinal chords and a section of one of the diagonal braces are positioned one behind the other at a distance from each other. These two sections are connected to each other by a transverse brace or support, which runs straight and in the direction of the structural direction. This structural direction is identical to the structural direction mentioned above if at least one of the additional braces described above is present. Regarding the advantages of this embodiment, reference is made to the preceding description of the diagonal braces running at an angle to each other with an additional brace.

[0036] Furthermore, the invention relates to a coordinate measuring machine with the connecting element according to one of the embodiments described in this description. The connecting element is connected at one end to a first part of the coordinate measuring machine and at the opposite end to a second part of the coordinate measuring machine.

[0037] Regarding the procedure, it is proposed that the connecting element be connected to a first part of a coordinate measuring machine in one end area and to a second part of the coordinate measuring machine in the opposite end area.

[0038] According to one embodiment of the coordinate measuring machine, a sensor of the coordinate measuring machine, which is used to measure the coordinates of a measured object during the operation of the coordinate measuring machine, is connected to a base of the coordinate measuring machine via the connecting element.

[0039] Alternatively or additionally, the connecting element is movable and the sensor is moved into a different position by a movement of the connecting element or can be moved into a different position and / or the sensor is aligned differently by a movement of the connecting element or can be aligned differently.

[0040] Exemplary embodiments of the invention will now be described with reference to the accompanying drawing. The individual figures in the drawing show: Fig. 1 A first embodiment of a connecting element in an isometric view from an oblique angle above, Fig. 2 the in Fig. 1. Connecting element shown in a side view, Fig. 3 that in Fig. 1 and Fig. 2 connecting elements shown in a top view, Fig. 4 a coordinate measuring machine with two different connecting elements and Fig. 5 a second embodiment of a connecting element, wherein the connections of the connecting element are shown only schematically.

[0041] Fig. Figure 1 shows a connecting element 1 having four longitudinal straps 2, 3, 4, 5. The four longitudinal straps 2, 3, 4, 5 extend longitudinally along the connecting element 1 from a first connection area 21 to a second connection area 22. The connection areas 21, 22 are each part of a connection 19, 20. In the embodiment shown here, the connections 19, 20 are each part of a pivot joint. However, the type and function of the connection are irrelevant to the invention. Rather, the connections could, for example, also be for fixed mounting on another part of a coordinate measuring machine, or connections for implementing a ball joint, or connections for enabling linear movement of the connecting element relative to the part of the coordinate measuring machine to which the connecting element 1 is mounted when the coordinate measuring machine is in an operational state.

[0042] Fig. 2 and Fig. 3 also show views of the in Fig. 1. The connecting element shown is 1. The longitudinal belt 5 already mentioned is only visible from the top view. Fig. 3 recognizable as a longitudinal belt. In the views of the Fig. 1 and Fig. 2. This longitudinal chord 5 is completely or partially concealed by other areas of the connecting element 1. The four longitudinal chords 2, 3, 4, 5 are located at the corners of a parallelogram when viewed in a cross-sectional plane perpendicular to the longitudinal direction. That this parallelogram is not a rectangle is evident from the top view of Fig. 3. It should be noted, however, that terms such as top view, from above, from below, or from the side only refer to representations of the Fig. 1 to Fig. 3 are related and serve to describe the different orientations of the views and their content. In practice, this can be found in the Fig. 1 to Fig. The connecting element shown in Figure 3 can be mounted in different ways as part of a coordinate measuring machine. For example, the axis of rotation realized by the connections shown cannot be, in the assembled state, as would be expected from the Fig. 1 does not correspond to running from top to bottom, but rather from front to back or from left to right.

[0043] Returning to the arrangement of the longitudinal belts 2, 3, 4, 5, it is in Fig. 3 at the very top of the figure, regarding the orientation of the top view. Fig. 3 lower longitudinal belt 5 visible. In the Fig. 1. This longitudinal belt lies behind the front, upper longitudinal belt 3 in the direction of view. Furthermore, it is from Fig. 1 the rear upper longitudinal belt 2 is recognizable, which is visible in the top view of the Fig. 3 is visible near the rear lower longitudinal belt 5. Furthermore, it shows Fig. 3, that the representation of the Fig. 1 front lower longitudinal belt 4 inside of the one shown in the illustration of the Fig. 1 front upper longitudinal belt 3 is arranged. In the plane of the top view of the Fig. Therefore, the aforementioned rear longitudinal belts 2, 5 and the aforementioned front longitudinal belts 3, 4 are arranged offset from one another. This makes it possible to manufacture the connecting element 1 with only two mold halves and without slides or cores of the mold, with the demolding direction perpendicular to the plane of the figure. Fig. 3. To enable this, further features of the connecting element are provided, which are explained in the following description.

[0044] From above, the Fig. 3 are located at the top of the representation of the Fig. 3 Between the aforementioned rear longitudinal chords 2, 5, there are a total of four diagonal braces 13, 14. Two of these diagonal braces are designated with the reference numeral 13 because they run parallel to each other, and the same applies to two further diagonal braces 14, which also run parallel to each other, but not to the diagonal braces 13. The diagonal braces 13 extend from the lower rear longitudinal chord 5 in the illustration of the Fig. 1 upwards to the upper rear longitudinal belt 2. They each end in a contact area 15, which is shown in the illustration of the Fig. 1 lies behind the upper rear longitudinal chord 2. At this contact area 15, the diagonal strut 14 begins, extending diagonally downwards to the rear lower longitudinal chord 5.

[0045] The front longitudinal belts 3, 4 are also in the plane of view of the top view of the Fig. 3 are offset from each other parallel to each other. However, as mentioned, the upper front longitudinal chord 3 is located on the outside and the lower front longitudinal chord 4 on the inside of the arrangement. In the top view, it can also be seen that there are a total of four diagonal braces 9, 10 between the longitudinal chords 3, 4. Again, the diagonal braces 9 and 10 run parallel to each other in pairs. As can be clearly seen from the view of the Fig. As can be seen in Figure 1, the diagonal struts 9 extend from the upper left, starting at the connection area 21 or a web 28, and thus from the upper front longitudinal chord 3 to the lower right, to the lower front longitudinal chord 4. Adjoining these, the diagonal struts 10 extend from the ends of the adjacent diagonal struts 9 and from the lower front longitudinal chord 4 to the upper right, to the upper front longitudinal chord 3. They terminate at the aforementioned web 28 or at the connection area 22.

[0046] The aforementioned arrangement of the four longitudinal chords 2, 3, 4, 5, viewed in cross-section at the corners of a parallelogram, is not strictly necessary. Rather, the arrangement could, for example, also form the corners of a trapezoid when viewed in cross-section. In this case, for example, the arrangement would correspond to the representation of the Fig. The front upper longitudinal belt should be offset inwards and the front lower longitudinal belt should be offset outwards. In the top view of the Fig. In this case, the two upper longitudinal chords would be on the inside and the two lower longitudinal chords on the outside. Further combinations or variations of the relative arrangement of the longitudinal chords are possible. Furthermore, it is not absolutely necessary for the longitudinal chords to extend lengthwise and thus be parallel to each other. Rather, the at least three longitudinal chords (and this also applies in particular to exactly four longitudinal chords) can simply run along the longitudinal direction and thus, for example, form the framework for a connecting element that tapers conically in the longitudinal direction. Such a connecting element is in Fig. Figure 4 is shown and designated with reference numeral 43. However, two of the longitudinal belts extend parallel to each other.

[0047] The Fig. 1 to Fig. The connecting element 1 shown in Figure 3 has further diagonal braces, namely those diagonal braces that connect the upper longitudinal chords 2, 3 and the lower longitudinal chords 4, 5 respectively. The diagonal braces 7, 8 are again arranged in pairs parallel to each other. This also applies to the lower diagonal braces 11, 12, which are best seen from the top view of the Fig. 3 are recognizable. The upper diagonal struts 7 attach to the connection area 21 or to the web 28 and extend to the rear upper longitudinal chord 2. They thus connect the front upper longitudinal chord 3 to the rear upper longitudinal chord 2 via the connection area 21 or the web 28. The diagonal struts 8 connect the rear upper longitudinal chord 2 to the web 28 or the connection area 22 and thus indirectly to the front upper longitudinal chord 3. The lower diagonal struts 11, 12 connect the lower longitudinal chords 4, 5 to each other. The diagonal struts 11 connect the connection area 21 to the front lower longitudinal chord 4 and thus indirectly connect the rear lower longitudinal chord 3 to the front lower longitudinal chord 4. The diagonal struts 12 connect the lower front longitudinal chord 4 to another of the ones shown in the illustrations. Fig. 1 to Fig. 3 not easily visible bridge or with the connection area 22. Thus, they indirectly connect the lower rear longitudinal strap 5 with the lower front longitudinal strap 4.

[0048] Corresponding to the four longitudinal chords 2, 3, 4, 5 and the diagonal struts 7 to 14, which each connect two of the longitudinal chords 2 to 5, there are in the representation of the Fig. 1 upper diagonal braces 7, 8, front diagonal braces 9, 10, lower diagonal braces 11, 12 and rear diagonal braces 13, 14. The upper diagonal braces 7, 8 and the lower diagonal braces 11, 12, as well as the front diagonal braces 9, 10 and rear diagonal braces 13, 14, can each be described as opposite each other if one considers the viewing directions of the Fig. 2 and the Fig. 3. Viewing directions are selected that extend perpendicular to the longitudinal direction of the connecting element 1. There is a special feature regarding the upper diagonal struts 7, 8 and the lower diagonal struts 11, 12. Since the connecting element 1 can be manufactured using only two mold halves, and since the upper diagonal struts 7, 8 and the lower diagonal struts 11, 12 are visible in the top view of the Fig. 3 intersecting each other and thus actually running at an angle to each other, there are, in the top view of the Fig. At each of the 3 apparently existing intersection points, an additional strut 24, 25 is added, which originates from the Fig. 1 and the Fig. 2 are recognizable. These additional struts 24, 25 run in a straight line in the direction of a construction axis, which is perpendicular to the longitudinal direction. The direction of the construction axis is perpendicular to the plane of the figure. Fig. 3. Furthermore, the additional struts 24, 25 connect the corresponding pairs of the obliquely running upper and lower diagonal struts 7, 11 and 8, 12. They extend in the demolding direction, which is the same direction perpendicular to the plane of the figure. Fig. 3 is and is therefore equal to the direction of the construction axis. Although the additional struts 24, 25 run straight in the demolding direction, their surfaces form a small angle of approximately 2 degrees with the demolding direction, i.e., the surfaces run slightly obliquely to the demolding direction. The resulting draft angle facilitates demolding the mold halves from the connecting element. Preferably, all surfaces of all components along which the mold halves are moved during demolding have such a draft angle. The draft angle is also visible from the top view of the Fig. 3 recognizable, namely on the edge lines of the diagonal struts 9, 10 and 13, 14 as well as on the edge lines of the connection areas 21, 22.

[0049] Due to the additional struts 24, 25, the stiffness of the connecting element 1 is particularly high in this demolding direction, and this design feature allows the use of only two mold halves, at least in the central longitudinal section of the connecting element 1 between the connection area 21 and the other connection area 22 at the opposite end. Depending on the design of the connections 19, 20, it is conceivable to use a core or a slide there during the manufacturing process using a mold. Due to the increased stiffness in the demolding direction, the connecting element 1 is particularly suitable for higher loads in this demolding direction and thus in the direction in which the additional struts 24, 25 extend. Therefore, if, for example,If a high load is present at one of the ends in the longitudinal direction of the connecting element 1, it is advantageous if the connecting element 1 is mounted in such a way that the direction of gravity coincides with the demolding direction and thus with the direction of the course of the additional struts 24, 25.

[0050] As can be seen from the depiction of the Fig. As can be seen in Figure 1, the special design of the connecting element 1 has a further special feature. In the middle of its longitudinal extension, at the junction of the two middle front diagonal struts 10, 9 and at the junction of the two middle upper diagonal struts 8, 7, the aforementioned web 28 is located. Immediately at the junction of the upper diagonal struts 8, 7 and adjacent to this web 28, a transverse strut 29 extends, as shown in the illustration. Fig. 1 from top to bottom to the lower front longitudinal belt 4. This cross brace 29 also enables the production of the central longitudinal section of the connecting element 1 using only two mold halves and increases the stiffness in the demolding direction. If one considers the top view of the Fig. 3. A closer look at the transition of the lower central diagonal struts 12, 11 reveals another area where two components of the connecting element 1, which are not directly adjacent to each other, overlap. As can be seen from the view of the Fig. As can be seen in Figure 1, a transverse support 30 is located there, extending downwards from the rear upper longitudinal belt 2 in the demolding direction to the aforementioned transition area of ​​the two middle lower diagonal braces 12, 11. This transverse support 30 also increases the rigidity and allows production with only two mold halves. The transverse support 30 has essentially the same functions as the transverse brace 29, so the transverse support 30 can also be considered a transverse brace.

[0051] Depending on the orientation of the upper and lower longitudinal chords and diagonal braces, further such areas can arise in which such cross braces, cross supports, or additional braces are located. In the specific embodiment of the connecting element 1, which is described in Fig. 1 to Fig. As shown in Figure 3, such areas are located directly adjacent to the connection areas 21, 22. However, the overlaps at these points could be avoided with a slightly different arrangement of the diagonal struts.

[0052] Compared to the one in the Fig. 1 to Fig. Numerous modifications can be made to the connecting element 1 shown in Figure 3. For example, the length of the connecting element in the longitudinal direction can be chosen differently, and therefore the number (four in the case of connecting element 1) of the diagonal struts arranged in a zigzag pattern can be different. In principle, a specific diagonal strut at the front, back, bottom, or top does not necessarily have to be followed by another diagonal strut extending in a different direction in a zigzag arrangement. Furthermore, the offset of the diagonal struts in pairs opposite each other does not have to be half a period of the zigzag sequence of diagonal struts, as in connecting element 1, but can also be, for example, only a quarter or a third of the period. With regard to the upper and lower diagonal struts, this then means that the additional struts are no longer located at the positions shown in the top view. Fig. Figure 3 shows that, depending on the required transverse stiffness and the design of the overall structure, it could also be avoided that diagonal struts opposing each other in pairs in the demolding direction are present. Regarding the Fig. For example, diagonal braces 11 and 8 could be omitted. However, cross brace 29 and cross support 30 could be retained. Thus, while there would not be an additional brace to connect opposing diagonal braces, there would at least be a cross brace or cross support extending from a longitudinal chord to a diagonal brace. In this case, this cross brace or cross support runs in a structural direction perpendicular to the longitudinal direction and connects the skew structural components, namely a longitudinal chord and a diagonal brace. These components are then positioned at a distance from each other and one behind the other in the structural direction. This configuration is not only found in variations of the specific design in Fig. 1 to Fig. The connection element 1 shown in section 3 is possible, but generally.

[0053] Fig. Figure 4 shows a coordinate measuring machine 31, which has a fixed base 33. A column 35 extends upwards from this base 33. A guide 37 is located on this column 35 for guiding the movement of a carriage 39 in the longitudinal direction of the column 35. If the vertical axis is designated as the Z-axis, then the Z-axis extends, for example, in the longitudinal direction of the column 35, and a relative movement of the carriage 39 to the column 35 along the guide 37 in the Z-direction is possible.

[0054] The slide 39 has a first joint 40 for the rotation of a first connecting element 41 relative to the slide 39. The axis of rotation of this joint 40 extends parallel to the longitudinal axis of the column 35. The first connecting element 41 therefore has a connection that forms part of the first joint 40. A second joint 42 is formed at a connection of the first connecting element 41 opposite this connection, through which the first connecting element 41 is rotatably connected to a second connecting element 43. The axis of rotation of the second joint 42 is also aligned parallel to the longitudinal axis of the column 35.

[0055] The second connecting element 43 has a connection to the second joint 42 and, at its opposite end, a connection for mounting a sensor 36. The sensor 36 is, for example, a tactile push button as shown.

[0056] Connecting elements 41 and 43 are each designed with longitudinal chords, which are connected to each other in pairs via diagonal braces. Details of the construction of connecting elements 41 and 43 are described in the Fig. 4 not shown. It is only apparent that there are longitudinal belts and diagonal braces between the connections.

[0057] ZB, the connecting element 1 can be made of Fig. 1 to Fig. 3 instead of the first connecting element 41. In this case, the distance between the axes of rotation of the joints 40, 42 would change, since the lengths of connecting element 1 and connecting element 41 differ.

[0058] Fig. Figure 5 shows a further embodiment of a connecting element 1. In Fig. 5 will use the same reference symbols as in Fig. 1 to Fig. 3 is used, but not for identical components, rather for corresponding components. The in Fig. The connecting element 1 shown in Figure 5 has only three longitudinal straps 2, 3, 4. In the illustration of the Fig. In the diagram, longitudinal straps 2 and 3 are the upper longitudinal straps, and longitudinal strap 4 is the only lower longitudinal strap. In a cross-section perpendicular to the longitudinal direction of the connecting element 1, longitudinal straps 2, 3, and 4 are therefore located at the vertices of a triangle. Preferably, the longitudinal straps 2, 3, and 4 are arranged such that they form an equilateral triangle.

[0059] Again, the connecting element 1 is designed such that, at least in its central longitudinal section (i.e., between the connection areas 21, 22), it can be manufactured using only two mold halves. Slides or cores are also not required in this central longitudinal section. The demolding direction extends in the illustration of the Fig. 5 from front to back, specifically in the plane of the zigzag chain of diagonal struts 7, 8. Viewed in this demolding direction, or more precisely in a plane perpendicular to the demolding direction, the rear upper longitudinal chord 2 and the front upper longitudinal chord 3 are offset from each other. In other words, the front upper longitudinal chord 3 is lower than the rear longitudinal chord 2.

[0060] Nevertheless, even in the connecting element 1 with its only three longitudinal chords, two groups of diagonal struts 9, 10 on the one hand and 11, 12 on the other, arranged in a zigzag pattern one behind the other, run at a distance from each other, at least in their central extension section. Again, the pairs of diagonal struts 9, 11 and 10, 12 run obliquely to each other and one behind the other in the demolding direction, also at a distance from each other. Additional struts 24, 25 are located at the overlap areas present when viewed in the demolding direction. Due to the in Fig. From the selected viewing direction, the additional struts 24 are more clearly visible than the additional struts 25. Further overlap areas, particularly between a longitudinal chord on the one hand and a diagonal strut on the other, are not required or present due to the design with only three longitudinal chords. However, such overlap areas could be present at the connection areas 21 and 22.

[0061] Therefore, the connecting element 1 exhibits high stiffness in the aforementioned demolding direction, although it is shown in the representation of the Fig. 5 below only has a longitudinal belt 4 and no diagonal struts extend zigzag-shaped in a plane spanned by the longitudinal direction of the connecting element 1 and the demolding direction. List of reference symbols 1 connecting element 2 - 5 longitudinal belt 7 - 14 diagonal brace 15 Contact area 19, 20 connection 21, 22 Connection area 24, 25 Additional strut 28 Bridge 29 Cross brace 30 Cross support 31 Coordinate measuring machine 33 Base 35 pillar 36 Sensor 37 Leadership 39 sleds 40, 42 joint 41, 43 Connecting element

Claims

[1] Connecting element (1), in particular arm, of a coordinate measuring machine, wherein the connecting element (1) comprises: - connections (19, 20) on end regions of the connecting element (1) which are opposite one another in a longitudinal direction for mounting the connecting element (1) to at least one other part of the coordinate measuring machine, - at least three longitudinal belts (2, 3, 4, 5) extending from one end region to the other end region along the longitudinal direction, - a plurality of diagonal struts (7 to 14) each extending along a direction oblique to the longitudinal direction from one of the longitudinal chords (2, 3, 4, 5) to another of the longitudinal chords (2, 3, 4, 5) and connecting them to one another, characterized byin that at least one pair (7 and 11, 8 and 12; 9 and 11, 10 and 12) of diagonal struts (7 to 14) is present, which consists of a first diagonal strut (7, 8; 9, 10) and a second diagonal strut (11, 12; 11, 12), which, viewed in a construction direction which runs transversely to the longitudinal direction, are located one behind the other at a distance from one another and run skewed to one another, wherein the first diagonal strut (7, 8; 9, 10) and the second diagonal strut are connected to one another by an additional strut (24, 25) which runs rectilinearly and in the direction of the construction direction. [2] Connecting element according to claim 1, wherein, viewed in the direction of a construction axis extending transversely to the longitudinal direction, at least one of the diagonal struts (7 to 14) and at least one of the longitudinal chords (2, 3, 4, 5), which the at least one of the diagonal struts (7 to 14) connects to another of the longitudinal chords (2, 3, 4, 5), lie next to one another and run offset from one another in such a way that the at least one of the diagonal struts (7 to 14) runs in a first plane containing the construction axis and the at least one of the longitudinal chords (2, 3, 4, 5) runs in a second plane parallel to the first plane. [3] Coordinate measuring machine (31) with the connecting element (41, 43) according to one of the preceding claims, wherein the connecting element (41, 43) is connected in one end region to a first part (39, 41) of the coordinate measuring machine (31) and is connected in the opposite end region to a second part (43, 36) of the coordinate measuring machine (31). [4] Coordinate measuring machine according to claim 3, wherein a sensor (36) of the coordinate measuring machine (31), which is used during operation of the coordinate measuring machine (31) for measuring coordinates of a measuring object, is connected to a base (33) of the coordinate measuring machine (31) via the connecting element (41, 43). [5] Coordinate measuring device according to claim 4, wherein the connecting element (41, 43) is movable and by a movement of the connecting element (41, 43) the sensor (36) is brought into a different position and / or is aligned differently. [6] Method for producing a connecting element (1), in particular an arm, of a coordinate measuring machine, wherein connections (19, 20) of the connecting element (1) are produced at end regions of the connecting element (1) that are opposite one another in a longitudinal direction, in order to be able to mount the connecting element (1) via the connections (19, 20) on at least one other part of the coordinate measuring machine, the method further comprising: - producing at least three longitudinal belts (2, 3, 4, 5) such that the longitudinal belts (2, 3, 4, 5) extend from one end region to the other end region along the longitudinal direction, - producing a plurality of diagonal struts (7 to 14) such that the diagonal struts (7 to 14) each extend along a direction running obliquely to the longitudinal direction from one of the longitudinal chords (2, 3, 4, 5) to another of the longitudinal chords (2, 3, 4, 5) and connect them to one another, wherein at least one pair of the diagonal struts (7 to 14), which consists of a first diagonal strut (7, 8; 9, 10) and a second diagonal strut (11, 12; 11, 12), is produced such that, viewed in a construction direction running transversely to the longitudinal direction, they lie one behind the other at a distance from one another and run skewed to one another, wherein the first diagonal strut (7, 8; 9, 10) and the second diagonal strut (11, 12; 11, 12) are connected by a additional struts (24, 25) running straight and in the direction of the construction direction are connected to one another. [7] Method according to claim 6, wherein, viewed in the direction of a construction axis extending transversely to the longitudinal direction, at least one of the diagonal struts (7 to 14) and at least one of the longitudinal chords (2, 3, 4, 5) which the at least one of the diagonal struts (7 to 14) connects to another of the longitudinal chords (2, 3, 4, 5) lie next to one another and are offset from one another in such a way that the at least one of the diagonal struts (7 to 14) extends in a first plane containing the construction axis and the at least one of the longitudinal chords (2, 3, 4, 5) extends in a second plane parallel to the first plane. [8] Method according to claim 6 or 7, wherein the connecting element (41, 43) is connected in one end region to a first part (39, 41) of a coordinate measuring machine (31) and is connected in the opposite end region to a second part (43, 36) of the coordinate measuring machine (31).

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