Monolithic Weighing Block

Abstract

Monolithic weighing block manufactured according to the principles of generative manufacturing (3D printing). [Solution] The weighing block B includes linkages Lo, Lu connected to the weighing receiver F via a support joint GS, and a load receiving portion A for receiving the force of weight introduced along the height direction Z, the other ends of the linkages Lo, Lu being connected to the load receiving portion A via a linkage joint, whereby the load receiving portion A is guided parallel to the height direction Z relative to the weighing receiver F. The individual components of the weighing block B are configured to be monolithically connected together by being built layer by layer based on the principles of 3D printing.

Description

[Technical field]

[0001] The present invention relates to a monolithic weighing block and to a method for manufacturing the same. [Background technology]

[0002] Monolithic weighing blocks ("monoblocs") for weighing cells are known from the prior art. They contain one or more linkages and further components of the lever mechanism integrally connected thereto, such as parallel linkages, load receptors, areas referred to as weighing receivers, etc. What is referred to here as "weighing receiver" is an area of ​​the weighing block which remains essentially stationary during operation and serves to form a support or pivot point for the lever. Components of the electromagnetic force compensation (often permanent magnets) as well as position detectors are also carried by the weighing receiver. Summary of the Invention [Problem to be solved by the invention]

[0003] The monolithic design avoids in particular thermal stresses and eliminates the production costs that may arise from assembling the individual components of the weighing block. However, machining such weighing blocks is not possible arbitrarily, since the individual components may be located one behind the other in a first direction and must be separated from one another by corresponding cuts perpendicular to this direction (undercuts). Removal of material from the monoblock is therefore only possible at or in such directions, where other components do not impede access to the tool. Moreover, the material that is not removed but is functionally superfluous gives the monoblock unnecessary weight and the production of undercuts is expensive.

[0004] The production of monoblock structures is, in the prior art, limited to the machining of three-dimensional objects, where material can be precisely removed, for example by milling, erosion, drilling, etc. The remaining material areas form the individual elements of the monoblock, which are connected to one another. Since material removal is not possible at any position inside the monoblock, there is also limited shaping potential for constructing the individual elements, in particular for achieving the required stiffness with as little weight as possible. [Means for solving the problem]

[0005] The object of the present invention is therefore to provide a monoblock and a method for producing the same, which makes it possible to overcome these drawbacks. 23 The problem is solved by the method described in .

[0006] The findings on which the invention is based make it possible to produce monoblocks of particularly low weight, based on the principle of generative manufacturing known as 3D printing, in which thin layers of material are stacked one on top of the other in one direction, for example in the longitudinal direction X, and are thus gradually built up into a three-dimensional object. Unlike the prior art known so far, in which monoblocks are produced by material removal from a solid material, here the monoblock with its components is built up layer by layer by material addition. Surprisingly, the applicant has been able to verify in experiments that the high requirements for dimensional accuracy in the micrometer range when producing monoblocks can also be achieved with monoblocks produced by 3D printing. The preconceived notion of low production accuracy with 3D printing has also been overturned, even for the configuration of thin sections or joints, which in conventional monoblocks are often produced by parallel holes located closely next to each other. The use of 3D printing in this particular application for monoblocks offers several significant advantages:

[0007] In known monoblocks, functionally redundant material can only be removed to a limited extent, since certain components of the weighing block make tool access difficult or even impossible. The weighing block is accordingly heavier than necessary. Furthermore, relatively thick material areas heat up or cool more slowly than relatively thin material areas when the ambient temperature changes, so that time unnecessarily passes until a steady operating condition is reached. A monoblock manufactured according to the invention has material only where it is functionally required, so that the total weight is reduced to a minimum. The configuration of the individual components of the monoblock as a rod structure or at least with the smallest possible individual cross section further reduces the sensitivity to temperature changes.

[0008] - Up until now, it was necessary to process the blank block with tools (especially milling tools) from different sides, thereby removing material, in order to be able to mill out individual components, in particular inside the weighing block, from the whole. Such costly processing can be avoided with the present invention.

[0009] - Often complex weighing blocks (e.g. with two or more levers) cannot be produced without undercutting the block. To do this, material must be removed inside the block in a first direction and then in a second direction perpendicular to this. To be able to reach the machining position with a tool in both these cases, machining openings are often required in other components of the weighing block, in particular in the parallel linkages, which weaken them. In 3D printing, on the other hand, undercuts can be formed by zones in which the material layer is not built up. Tool guidance for material removal is not necessary here.

[0010] -Due to the high manufacturing precision, the individual components of the monoblock can be configured by 3D printing to be located very closely to one another, so that smaller intermediate spaces are required than would be possible with conventional tools. Erosion is also known for producing thin sections in a monoblock, but this requires that the section runs through the entire block, which severely limits the design freedom.

[0011] The individual components of the weighing block can be manufactured in such a way that they interpenetrate with one another or share part of the weighing block volume. This is possible in particular by the configuration of the components with cutouts or as rod structures, whereby sections of one rod structure can be created inside sections of the other. This technique, which results in a large number of undercuts, is not known in the prior art for monoblocks.

[0012] The weighing block according to the invention extends in a longitudinal direction X, a transverse direction Y perpendicular thereto, and a height direction Z perpendicular to both directions. At a first block end, the weighing block comprises a weighing receiver area, which is provided in particular for supporting a linkage or a lever. Parts of the force compensation system can also be attached to the weighing receiver. The weighing block further comprises two linkages extending in the longitudinal direction X and connected with their first ends to the weighing receiver via a support joint. With their second ends opposite the first ends, both linkages act on a common load receptor, which is guided by the linkages in the height direction Z relatively parallel to the weighing receiver. The load receptor serves to receive the force of the weight introduced in the height direction. Such a system, which in its simplest form does not require a force-transforming lever, is called a directly supported system, in which the movement of the load receptor caused by the force of the weight is compensated by a reaction force generated through the force compensation system. For example, a coil as part of this force compensation system can be arranged directly on the load receptor.

[0013] Such a lever-free system already allows the construction of components with the lowest possible weight by 3D printing. Furthermore, the weighing receiver, which must be constructed up to the coil area of ​​the load receiver to receive the magnets belonging to the force compensation system, for example, can penetrate the linkage. The weighing receiver and the linkage can be constructed in this way to be partially interlocking with each other, so that the individual rods, struts or other material areas of the linkage only have to have a minimal distance to the material areas of the weighing receiver.

[0014] A preferred embodiment of the weighing block comprises at least one first lever extending (preferably in the longitudinal direction X) between a first end region and a second end region (this extension direction, in which the lever constitutes a lever arm for changing the force, can also be called the main extension direction). The lever is connected in the first end region to the load receiver via a connecting member, which ensures a further transmission of the force from the load receiver to the lever. The connecting member comprises at least one load joint, whereby a section of the connecting member is pivotable relative to the lever or the load receiver about a pivot axis formed by the load joint. Furthermore, the first lever is also connected in the first end region to the weighing receiver via a support joint, which then also constitutes a pivot axis. The embodiment with at least one lever can be produced particularly well by 3D printing, since in that case the advantages mentioned above come into full effect.

[0015] The term "support joint" is used in the following to mean a joint which connects or supports a movable part of the monoblock, in particular a lever or a linkage, to the weighing receiver. A "linkage joint" is referred to as a joint via which a linkage is connected to a load receptor. Two movable sections of the weighing block are connected to one another via a "load joint". In particular, the load receptor is connected to the end of a lever via one or more load joints, the levers are also connected to one another via load joints. The load joints are usually part of a connecting element. All these joints each form a pivot axis around which the two sections which are connected to one another via a joint can be pivoted relative to one another.

[0016] A particularly preferred embodiment of the invention provides for the load joint to be configured as a cross spring joint. In this case, the two sections to be connected to one another in a jointed manner are connected to one another via at least two material webs which preferably do not come into contact with one another in the region of the pivot axis, one of the material webs forming an angle (α≠0°) with the other material web in a projection along the pivot axis. In contrast to so-called thin-walled joints, the pivot axis is generated here by two material webs which are axially located one behind the other and cross each other. The crossing angle is preferably in the range 45°<α<135° and is at most exactly 90°.

[0017] Due to the material webs lying one behind the other in the axial direction, the cross spring joint cannot be produced in the direction of its pivot axis without undercuts. At the same time, the crossing material webs have a horizontal or vertical extent transverse to the pivot axis, i.e. the joint takes up a certain amount of space transverse to the pivot axis. The load joint, through which the force is introduced into the lever in the region of the lever end, is advantageously arranged in the longitudinal direction of the lever in close proximity to the support joint supporting the lever, so that a short lever arm or a sufficiently high lever transmission ratio can be achieved, the pivot axes of both joints running parallel. However, the construction of the load joint as a cross spring joint is an obstacle to the construction of closely adjacent support joints, insofar as both joints are produced in the conventional manner, i.e. by removing material from a monolithic block. That is, each joint is then often constructed in the direction of the pivot axis by means of a bore, the diameter of which determines the minimum distance to the other adjacent joint. The cross spring joint produced in this way can only be constructed with a small axial distance relative to the other joint if both joints are located one behind the other while being axially offset from one another. In that case, however, the bore of one joint penetrates the design space of the other joint, which can only be prevented by costly undercuts. In contrast, the generative design of the weighing block according to the invention allows the construction of the support joint and the load joint with a small mutual distance, while at the same time applying the advantages of the cross spring joint for the load joint. This also works particularly well if the support joint of the lever, which is provided in the same lever end region as the load joint, is constructed as a cross spring joint of the above-mentioned type. In this case, the two joints are located one behind the other when viewed along the respective pivot axes (running parallel to one another) and their extent transverse to the respective pivot axes is greater than the distance between the respective pivot axes that defines the length of the lever arm.With conventional manufacturing methods, due to undercuts and due to the lack of material required around the joints for processing, such a structure is at least economically not possible, and probably not even technically possible, whereas with 3D printing, the joints can be configured and positioned in the above-mentioned manner, without the need for complex processing processes for this purpose.

[0018] The component serving for force transmission between two levers or between a lever and a load receiver comprises, in a preferred embodiment of the invention, at least one, preferably two cross spring joints of the type mentioned above, which are mutually spaced by a material web that also transmits the lever force. Depending on the extent of the respective joint transversely to the pivot axis, the joints can be arranged offset, one behind the other or side by side / one above the other, when viewed along their parallel pivot axis. Also in the connecting element, 3D printing allows for a mutually spaced arrangement of one or two cross spring joints (and the associated undercuts), and the configuration of the connecting element with at least one cross spring joint also independently provides the advantage of defining the pivot axis not via a thinned section, providing this special design form for the load joint itself. (This configuration of the connecting element according to the invention is not necessarily connected to the weighing block according to the invention, and independently provides the above-mentioned preferably separately protectable advantages).

[0019] Another preferred embodiment of the invention provides for the pivot axis of the support joint or linkage joint arranged on the linkage to be located at the vertex of a parallelogram, and the linkage is located one above the other in the Z direction in the form of an upper and lower linkage and extends between the load receiver and the weighing receiver in the X direction perpendicular thereto (other spatial arrangements are also conceivable). Such an arrangement advantageously makes it possible for the weighing receiver to extend between the linkages and thus form new support points.

[0020] Another preferred embodiment of the invention provides that at least one load or support joint connected to a lever is surrounded by the outer casing area of ​​the lever on one side, preferably on both sides, as viewed in the direction of its pivot axis. The lever can then also extend laterally of the joint (e.g. as viewed in the transverse direction Y) and have a sufficient Z dimension there for the desired stiffness. The arrangement of the joint laterally with respect to the lever connected to it offers design advantages: both members of the weighing block to be connected to each other by the joint can be arranged at least partially or completely one behind the other in the direction of the pivot axis, so that in this area the overall design height of both members, including the joint located between them, is less than the sum of the design heights of the individual members and the joint. For example, a lever to be pivoted about the Y axis can be supported on a weighing receiver via a support joint that is substantially in front of or behind the lever in the Y direction. In the prior art, the lever always passes by the pivot axis at a distance in the X or Z direction, because the configuration according to the invention requires (preferably) thin undercuts that are hardly producible in manufacturing by cutting.

[0021] Another preferred embodiment of the invention provides that at least two joints acting on the same lever are located one behind the other in the direction of their respective mutually spaced pivot axes, such that the joint cross sections formed perpendicular to the respective pivot axes overlap in the direction of the pivot axes in the projection. The advantages already explained above for load joints with a support joint when using cross spring joints can also be applied in the 3D printing according to the invention to other joint configurations with a certain lateral extent transverse to the pivot axis. Thereby, it is possible to select the pivot axis distance of two joints connected to the same lever, whose respective pivot axes are not aligned, spaced apart in one direction (X, Y, Z), smaller than the extent of at least one of the joints in said direction, so that a jointed connection of the levers is possible in a small space. Typically relevant here are combinations of different types of joints, i.e. load joints with support joints, linkage joints with load joints, etc. What is usually the case in this case is that the respective pivot axes are spaced apart from one another, i.e. are not aligned in a straight line.

[0022] The circumstance that the pivot axis of a joint according to the invention can also move through the element guided by the joint allows for a further preferred embodiment, in which at least one lever has a pocket for receiving the joint connected to it. The pocket thus surrounds the joint on at least one side and protects it from accidental loading and dirt. The monolithic arrangement of the pocket constituted by the lever and the joint located therein, which connects the lever in a pivotable manner, is hardly producible by conventional machining methods.

[0023] In addition to the space-saving arrangement of the joint relative to the lever (the pivot axis can also pass through the lever), each element of the pocket can assume several functions. The pocket then comprises at least one wall section from which on one side a first support section projects for connection with the joint, for example by acting there on two intersecting webs of a cross spring joint. On the other side of the wall section another support section can project for connecting elements of another joint. For example, it is conceivable that on one side of the pocket wall of the lever, seen in the transverse direction Y, a support joint is formed which supports the lever on the weighing receiver. The pocket wall then extends approximately along the XZ plane. The support joint acts on the lever side (for example from below) on a support section which projects laterally from an upper region of the pocket wall in the transverse direction Y. The joint then runs essentially next to or along the pocket wall and its pivot axis runs in the transverse direction Y.

[0024] On the other side of the pocket wall, diametrically opposite to the first support section, from the lower region of the wall, another support section projects in the transverse direction Y (opposite to the support section on the other side), which is intended to form the lower point of application of the connecting element. For this purpose, the connecting element has a load joint to be connected with the other support section, which runs from this support section upwards along the pocket wall on this side and whose pivot axis also runs in the transverse direction Y. Then, on both sides of the pocket wall, respectively, there are respectively arranged joints which act on the respective support sections which project towards the respective different sides of the pocket wall. The two support sections together with the pocket wall thus form an approximately "Z"-shaped cross section with sections which run perpendicular to one another.

[0025] The pivot axes of both joints can thus be located in close proximity next to each other, which produces a very high lever transmission ratio and at the same time allows the lever to configure a high bending stiffness with respect to bending moments about the Y axis, for example due to the height of the pocket wall. Both joints are located in front of or behind the pocket wall as viewed in the Y direction, preferably at a small Y distance relative to the pocket wall, so that the respective lateral extent transverse to the pivot axis of each joint does not restrict the configuration of the respective other joint, as is the case with the methods known from the prior art in cutting processes.

[0026] In another preferred embodiment of the invention, at least one further lever is provided, which has substantially the same purpose as the first lever, so that both levers are arranged one behind the other to achieve a higher transmission ratio of the weight force introduced via the load receptor than would be possible with only one lever. More than two levers can also be arranged one behind the other for this purpose, in which case the lever supported in the middle can also transmit additional forces with the same value.

[0027] The further lever extends between the first and second end regions and can extend in a longitudinal direction X or in the direction of extension of the first lever. However, the construction of the monoblock in 3D printing according to the invention allows the extension directions of the levers connected to one another to be selected differently. For example, the first lever can extend in the longitudinal direction X, whereas the further lever connected to it can extend obliquely or perpendicularly thereto, for example in the transverse direction Y or in the height direction Z. The connecting element connecting the levers to one another then has two joints whose pivot axes do not run parallel to one another. The levers arranged one behind the other can therefore extend arbitrarily in space, as can the pivot axes of the joints connected to them, so that the pivot axes of two joints, in particular of two support joints, no longer run parallel to one another but (when virtually displaced to an intersection) form an angle (β ≠ 0) (whereas in the previously known methods for producing monolithic weighing blocks, for processing reasons, it was customary to configure the pivot axes of all levers parallel to one another, since pivot axes running transverse to one another are not technically or economically possible to produce, in particular when several levers are connected). This allows high transmission ratios along different spatial directions, so that the extent of the weighing block can be optimally reduced in the X-, Y- or Z-direction, depending on the requirements.

[0028] The further lever is connected at its first end region to the second end region of the first lever via a connecting member having a load joint and further connected to the weighing receiver via a support joint. The further lever may be connected at its second end region to a further lever or may carry a component of a force compensation system and is then considered as the "last" lever.

[0029] If the second lever extends in substantially the same direction as the first lever connected to it, 3D printing offers a favorable option for arranging or configuring the levers in a space-saving manner. For example, one of the two levers can have a notch into which a section of the respective other lever protrudes or penetrates. The levers can then partially or completely penetrate each other, thus enabling a space-saving design. For example, the first lever can have a notch extending in the longitudinal direction X and opening upwards and / or downwards in the height direction Z, which surrounds the lever on both sides in the lateral direction Y. A section of the second lever or other components of the weighing block can extend through this notch. In this way, both levers can be configured with a high surface moment of inertia and therefore a high stiffness with respect to bending about the Y direction, for which a certain spread in the height direction is necessary. At the same time, the levers can then be positioned partially one behind the other or interdigitated with each other in the lateral direction Y. Conventional monoblocks with such levers can only be produced with difficulty, or even at all, since the separation of the respective levers in the lateral direction Y is only possible with a tool fed in the height direction H. However, when the levers are between parallel linkages in the height direction Z, or when individual sections of one lever prevent the tool feed to the other lever, such processing is usually only possible through additionally necessary cutouts in the linkages or levers, which weakens their rigidity.

[0030] A special embodiment of the invention provides that the monoblock comprises at least two levers that penetrate each other so as to jointly pass through the volume area of ​​the monoblock. A special advantage of 3D printing in the context of a monolithic weighing block then consists in that the levers of the monoblock only perform a virtual movement, in particular in the context of electromagnetic force compensation, since any lever deflection by the force compensation system is immediately corrected again, i.e. the levers practically do not move relative to each other, but have the movement freedom for this. Since the levers do not perform a real pivoting movement and accordingly do not require space for this, they can be configured to interlock with each other, so that the first lever is closely adjacent to or surrounded to a large extent or completely by the second lever. For example, a first lever configured as a rod structure around an elongated internal space extending in the extension direction of the lever is conceivable. The second lever is arranged partly or completely in the internal space of the first lever.

[0031] In this case, the individual sections or rods of the first lever can also penetrate the internal space in order to stably configure this lever. It is only necessary to ensure that the second lever does not collide with its respective sections or rods with the first lever. Since the levers do not perform actual pivoting movements, the individual sections of both levers can be configured to be located very close to each other, for example with a distance of less than 1000 μm or 500 μm. The individual sections or rods of each lever can then run in all spatial directions or obliquely thereto or in a curved shape, thereby achieving the required lever stiffness. At the same time, the respective levers can inseparably penetrate each other, by the mutually suspended sections of one lever, which form a closed material chain, passing through the corresponding material chain of the other lever.

[0032] Instead of being configured as a rod structure, the components of the weighing block can also exhibit a half-timbered structure with as thin walls as possible, formed by regular quadrangles, for example rhombuses, penetrating the component along one or more directions. The material-free areas can have the form of regular geometric bodies (cuboids, pyramids, spheres, prisms, etc.).

[0033] At least two components of the weighing block expediently form, in a section transverse to the directions X, Y, Z, in particular to the longitudinal direction X, a cross-sectional area with a cross section consisting of a number of separated partial areas, the envelopes of both cross sections at least partially overlapping, and at least one partial area of ​​one cross section being located inside the envelope of the other cross section. Components that are of particular concern here are weighing receivers, load receivers, levers, connecting elements, linkages or joints. By "envelope" is meant here the lateral division of the cross sections, which in each case connects the most outermost points of the cross sections with one another, like a kind of rubber band that is centered around the cross section. As is evident from this, the material area of ​​one component can extend through the material area of ​​the other component and is at the same time laterally looped as a result of this. A space-saving interlocking arrangement of the components is thus particularly well possible.

[0034] The mutual penetration does not have to be so carried out that one lever is placed completely inside the other: partial penetration is also possible, in that the volume enclosed by one lever partially projects into the volume enclosed by the other lever, which reduces the volume necessary to construct the weighing block and in particular its weight.

[0035] In another preferred embodiment of the invention, it is provided that the weighing receiver extends in the longitudinal direction X starting from the first block end between the respective parallel linkages and / or through the respective load receptors. The extension through the load receptor in particular offers the advantage that components of the force compensation system, such as permanent magnets or elements of the position detector, can also be supported beyond the load receptor. The weighing receiver extended into the area of ​​the load receptor also makes it possible to configure a support point for the lever inside the space surrounded by the load receptor. This allows the lever to be installed as long as possible from the load receptor to the first block end without being limited only by the space available between these two components. For example, it is conceivable to configure a support joint for the first lever, into which a force is to be introduced from the load receptor, partially or completely inside a recess in the load receptor. The weighing receiver can also have a corresponding recess, so that an end region can extend from the lever into the weighing receiver, whereby the largest possible lever length can also be realized there. A "cutout" in this case is to be understood as a material-free area extending in the direction X, Y or Z, which, in projection along this direction, is surrounded on all sides by the material of the respective component. (Such a guidance of the weighing receiver through the load receptor according to the invention is not necessarily connected to the weighing block according to the invention, but, regardless of this, provides the above-mentioned, preferably separately defensible advantages.)

[0036] It is further conceivable to configure the load receptors in the region between the upper and lower parallel linkages, so that they cover the load receptors in the height direction Z. The linkages can then be configured with a maximum length, the load receptors being essentially located within the vertices of the parallelogram formed in the lateral direction Y by the pivot axes of the linkage joints. (Such a configuration of the load receptors is not necessarily connected to the weighing block according to the invention, but even without this provides the above-mentioned preferably separately protectable advantages.)

[0037] The generative design of the weighing block according to the invention makes it possible for a lever to be surrounded, for example, on both sides in the lateral direction Y by another lever, which in turn is surrounded on both sides in the same direction by the weighing receiver F. That is to say, the lever is located surrounded laterally between the sections of the weighing receiver and is particularly well protected due to the reduced design height of the weighing block.

[0038] The above-described cross spring joint can also be produced in a preferred development by generative modeling according to the invention. At least three material webs jointly connect the first section to the second section, at least one of which forms an angle (α) with at least two other material webs in a projection along the pivot axis. At least three material webs are then constructed accordingly, preferably with the central web inclined by an angle (α) to both other webs pointing in the same direction. This angle preferably complies with the condition 45°<α<135°, preferably at most 90°. To construct such a joint, several material-free areas or undercuts located one behind the other in the pivot axis direction are required, which are hardly producible by cutting methods, especially if other joints of the same kind are to be provided at close intervals from them. However, the special stability of a cross spring joint consisting of three or more webs can be achieved by generative modeling of the joint. (The cross spring joint construction according to the present invention is not necessarily linked to the weighing block according to the present invention, but rather provides the above-listed and preferably separately defensible advantages without regard thereto.)

[0039] At least one section of the lever or the linkage or the joint or the weighing receiver or the load receiver or the connecting member is preferably configured as a rod structure. The entirety of these components is preferably configured as a rod structure, and it is highly preferred that the entire weighing block has such a structure. This allows the weight of the weighing block to be minimized, while at the same time the rod structure ensures the required stiffness of the individual components. The above-described mutual penetration of the two levers can also be realized for any other components of the functionally identical or different weighing blocks. The term "rod structure" is used here as representative of a structure consisting of several individual material sections combined together, in which mainly longitudinal forces but no or only little bending moments occur.

[0040] 3D printing of the weighing block according to the invention allows the construction of the individual components with less material, with high rigidity and space-saving arrangement relative to one another. Thus, an embodiment according to the invention is characterized in that the cross-sectional area of ​​at least 50%, preferably more than 80%, of all cross-sections occupied by the levers perpendicular to the main extension direction is smaller than the cross-sectional area of ​​the surface circumscribed by the envelope of the respective cross-section. As the relationship between the areas of the individual partial surfaces to be added together that give rise to the cross-section and the area enclosed by the envelope makes clear, 3D printing according to the invention allows a significant material saving in the very complex construction of the monolithic weighing block and at the same time allows a clever arrangement of the individual components in the areas vacated by the material saving.

[0041] The generative creation of the weighing block is not limited to the block as a whole, i.e. the advantages of 3D printing, which were surprisingly found for each component of the weighing block, apply to each component by itself. The subject of the invention is therefore also the components of the weighing block produced in this way, as well as the production of such components as 3D printing.

[0042] The method of the invention for producing weighing block components or the weighing block as a whole relies on the construction of the individual components by repeatedly applying thin material layers one above the other (3D printing). Starting from a first end, for example starting from a first block end, the block is preferably built up in thin layers, for example in the longitudinal direction X. The material-free areas in the interior of each layer form intermediate spaces or undercuts that separate the individual components from one another. The production of a component is preferably carried out "simultaneously" with the production of another component, where "simultaneously" is understood to mean that first all material areas of a certain layer are formed at a certain layer height and then the next higher layer is applied. In this way, the material construction of one component is interrupted by the material construction of at least one other component when both components require material construction at the same layer height. In theory, however, it is also possible to first construct one component partially or completely and subsequently produce another component.

[0043] Any material can be used for the weighing block, which on the one hand meets the requirements for high-precision 3D printing and on the other hand meets the requirements for normal material behavior in a monolithic weighing block. The monolithic construction of the weighing block does not exclude that different materials are used for different regions or components of the weighing block, which can nevertheless be monolithically connected to one another. For example, for the weighing receiver, which places particularly high demands on stiffness, a different material can be selected than for the load receptor, where the bending stiffness is possibly of only secondary importance. Furthermore, it is also conceivable to use electrically conductive materials, for example for printing coils or connections arranged on the last lever to position transducers or other sensors.

[0044] In one preferred embodiment, the weighing block is constructed partially or entirely of metal, preferably aluminum or an aluminum alloy.

[0045] The weighing block according to the invention is produced as a 3D print, although possibly necessary post-processing with cutting tools is not excluded.

[0046] An embodiment of a weighing block according to the invention will now be described in more detail with reference to the drawings, in which: [Brief description of the drawings]

[0047] [Figure 1] 1 shows a weighing receiver of a weighing block according to the invention; [Diagram 2] The embodiment of FIG. 1 is shown with a parallel linkage. [Diagram 3] The parallel linkage of FIG. 2 is shown with the load receptor acting thereon. [Figure 4] 4 shows a part of the load application part of FIG. 3 together with a first lever acting thereon. [Diagram 5] The first lever of FIG. 4 is shown with the second lever positioned below it. [Figure 6] 6 shows both levers of FIG. 5 joined by a connecting member. [Figure 7] A portion of the weighing receiver is shown with a lever projecting therein. [Figure 8] The weighing receiver is shown with the load receiving portions and the lever located between them. [Figure 9] 1 shows a side view of a weighing block according to the present invention. [Figure 10] 1 shows a schematic cross-sectional view of two levers passing through each other. [Figure 11] 1 shows a rod structure as an example of a linkage. [Figure 12] Two design examples are presented for each section of the weighing block component. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] FIG. 9 shows a schematic side view of a complete weighing block B according to the invention. The weighing block B extends in a longitudinal direction X, a transverse direction Y perpendicular thereto, pointing into the plane of the paper, and a height direction Z also perpendicular to both directions. A first (left-hand in FIG. 9) block end B1 is configured as a weighing receiver F over the entire Z height. Starting from the first block end B1, the weighing receiver F extends to the right in the longitudinal direction X with a reduced height towards the second block end B2. In the upper and lower areas of the first block end B1, upper and lower parallel linkages Lo, Lu, respectively, are provided at two support joints G, one behind the other in the transverse direction Y. S The pivot axis formed by the linkage joint extends in the lateral direction Y (not shown in detail).

[0049] The parallel linkages Lo, Lu extend in the longitudinal direction X to a load receiving portion A, which is provided for receiving the force of the weight indicated by the arrow. The parallel linkages Lo, Lu are connected to linkage joints G, which are located one behind the other in the lateral direction Y. R The pivot axis formed by the linkage joint and the support joint is located at the vertex of a parallelogram, so that the load receptor A is guided parallel in the height direction Z relative to the weighbridge by the parallel linkages Lo, Lu.

[0050] Between the upper and lower parallel linkages in the height direction Z not only extends the projecting section of the weighing receiver F but also the first linkage M and the second linkage H connected thereto. The second linkage H projects in the longitudinal direction X through the load receiver A and cooperates with its free end with a first part Q1 of an optical sensor Q, which detects the deflection of the lever relative to the second part Q2 of the optical sensor. The weighing receiver F also projects in the longitudinal direction X into a recess in the load receiver A and carries the second part Q2 of the optical sensor Q.

[0051] FIG. 1 shows in a schematic side view the completed weighing receiver F of the weighing block shown in FIG. 9. The weighing receiver F is partially constituted by a rod-like structure. At the first block end B1, the weighing receiver F is constituted by cutouts C which are provided for receiving the sections of the linkages H and M. The weighing receiver F has an outer contour of an approximately rectangular parallelepiped, the internal space remaining approximately free.

[0052] FIG. 2 shows the weighing receiver with the parallel linkages Lo, Lu arranged on it. These linkages have a half-timbered structure consisting of individual pyramids extending in the transverse direction Y. The upper side of the upper linkage Lo and the lower side of the lower linkage Lu are substantially closed, and both linkages have cutouts on the side facing away from the first block end B1 in the longitudinal direction X for accommodating the respective sections of the load receiving part A. The support joint G S via which the linkage is jointed to the weighing receiver F. The support joint is configured here as a cross spring joint.

[0053] FIG. 3 shows a schematic drawing of the load receiving part A. The load receiving part is the linkage joint G. R The support joint is connected to the parallel linkages Lo and Lu via the linkage joints, and the support joints have the same pivot axis A GS Or A GR , which in the embodiment of FIG. 3 all run parallel to one another in the transverse direction Y and are not fully illustrated. Load receiver A also shows an area with a half-timbered construction for weight reduction. The central area A of load receiver A M protrudes in the longitudinal direction X into the notch of the upper linkage Lo.

[0054] FIG. 4 shows the partially broken load receptor A from below in an oblique view. M In the region of the connecting element K, the connecting elements K are arranged as cross spring joints and are each connected to a pivot axis A which extends in the transverse direction Y. GLTwo load joints G arranged vertically in the height direction Z, L The upper load joint has area A of the load receptor A. M and serves to receive and further transmit the load introduced into the load receptor A. Between the two load joints of the connecting part K there is arranged a web which connects both joints to one another. The lower load joint fits into a pocket of the first lever H and acts on it in a first end region H1 of the lever H. The lever H extends in the longitudinal direction X as far as a second end region H2 where it is connected to the second lever M.

[0055] 5 shows the arrangement of a first lever H with a second lever M extending therethrough. The second lever M also extends in the X direction from a first end region M1 to a second end region M2 (see FIG. 6). In its first end region H1, the lever H is pivoted about a common pivot axis A for support on a weighing receiver (not shown). GS Two support joints G located one behind the other in the lateral direction Y form S The lever H is constructed almost symmetrically with respect to the central XZ plane, and the rear support joint G S are hidden in the respective areas of the lever structure in FIG. 5. Both support joints G S is configured as a cross spring joint (all cross spring joints shown in Figures 1 to 9 each comprise three webs located one behind the other in the direction of the pivot axis, which connect both sections to be guided in a mutually jointed manner, with the central web being inclined by 90° to the pivot axis relative to both other webs).

[0056] For a space-saving arrangement of both levers, the first lever H is pierced by a free space extending in the longitudinal direction X, which is occupied by the second lever M. Both levers are at least partially constructed as half-timbered structures.

[0057] FIG. 6 shows, from another perspective, how the first lever H is connected in its second end region H2 to the first end region M2 of the second lever M via a connecting member K. The connecting member K also contains two load joints arranged one above the other in the height direction Z (only the lower one is shown). Both load joints G L 4, the pivot axis A extends in the transverse direction Y. GL Both load joints are connected to each other via a web interposed between them. In contrast to the connecting member K in FIG. 4, here the web is pierced with a notch in order to reduce weight.

[0058] Lower load joint G L is located in a pocket T of the linkage M. The pocket T is aligned laterally Y with the lower load joint G L The wall sections W are connected to each other at their lower ends by a common support section V. The lower load joint G L acts on this support section V, thereby transferring the lever force transmitted by the first lever H through the connecting member K to the lever M. On the outside of both wall sections facing away from the lower load joint, there is a support joint G which supports the lever M on a weighing receiver (not shown). S (In Fig. 6, only the front joint is shown.) To support the lever M through this support joint, a lower load joint G L On the outer surface of each wall section W facing away from the wall section W, an upper support section V projects laterally outward in the lateral direction Y, which supports on its underside a support joint G which is configured as a cross spring joint. S Each wall section W of the pocket T thus has two support sections V, arranged on opposite sides in the lateral direction Y and offset from one another in the height direction Z, so that a cross section through each wall section, perpendicular to the longitudinal direction X, results in a substantially Z-shaped profile (with mutually perpendicular sections).

[0059] Both support joints G in the first end region M1 of the lever M S defines a pivot axis about which the lever can be pivoted relative to the weighing receiver. S Common pivot axis A of GS and the lower load joint G L Pivot axis A GL The distance between the joint G and the joint G determines the short lever arm of the lever M. To achieve a high transmission ratio, this distance should be chosen as short as possible. L ,G S have a certain extent transverse to the respective pivot axis (this extent is formed in particular by the webs of the cross spring joints), but based on the arrangement of the respective joints which are selected offset from one another in the transverse direction Y, these pivot axes can be formed in close proximity to one another.

[0060] the upper load joint G of the connecting member K acting in the second end region H2 of the lever H L For this purpose, the pivot axis A of the upper load joint is GL 2, the upper lever H is inserted into the upper lever H to such an extent that it passes through the upper lever H. This also results in a reduced design height, in particular in the height direction Z.

[0061] As mentioned above, FIG. 5 shows the support joint G provided in the first end region H1 of the lever H. S FIG. 6 shows a second support joint G, which faces this joint in the transverse direction Y. S (right edge of FIG. 6). There too, a pocket T is provided with a wall section which extends at least to one side of the support joint. A support section V projects outward from this wall section in the lateral direction Y, thereby forming an upwardly projecting support joint G. S It is designed to accommodate the web.

[0062] FIG. 7 shows the arrangement of FIG. 6, embedded in a weighing receiver F. Here it can be seen how both levers M, H in the region of the connection by the connecting piece K protrude into the recesses of the weighing receiver F, allowing the maximum lever length to be achieved. Furthermore, the front support joint G of the lower lever M S It can be seen how the weighing carrier is supported at its rear end in the X direction. The weighing carrier has an attachment area E1 for arranging the components of the force compensation system, in particular for arranging the permanent magnet D. Further in the X direction this is followed by another area E2 which is provided for receiving an element Q2 of the position detector Q.

[0063] Figure 8 shows the structure of Figure 9 in an oblique view, but without the upper and lower linkages Lo, Lu. One can see the coil P carried by the lower lever M via an extension screwed to it, which moves relative to a permanent magnet D carried by the weighing receiver F depending on the force of the weight received by the load receiver A and transmitted by the lever. The coil P and the permanent magnet D form elements of an electromagnetic force compensation system, by which the pivoting movement of the lever M is compensated and, from the coil current required for this, the force of the weight to be measured can be deduced.

[0064] The coil P and the permanent magnet D are arranged in the longitudinal direction X inside a recess in the load receiving part A in order to be able to configure the maximum lever length or transmission ratio in the shortest possible design space in the longitudinal direction X.

[0065] The individual components of the weighing block according to the invention preferably interpenetrate with each other, thereby reducing the design space. In the simplest case, this can take place by the first component having a recess into which the other component projects. However, it is particularly preferred that the components can also interpenetrate with each other, which is explained with reference to FIG. 10. Two components 1, 2 extending in the longitudinal direction X can be seen there in a cross section formed transversely to the longitudinal direction X. In this cross section, component 1 has an individual partial surface T1, whereas the cross section of component 2 is formed by combining the respective partial surface T2. The cross section of component 1 is circumscribed by an envelope V1, while the envelope V2 circumscribes the cross section of component 2. The mutual interpenetration of the two components is characterized in that the partial surface of each component is within the envelope of the other component. This allows a stable and particularly space-saving arrangement of the components. Naturally, more than two different components can also interpenetrate with each other in this way.

[0066] Moreover, as Fig. 10 clearly shows, the combined cross-sectional area of ​​the individual partial surfaces of a component is clearly smaller than the area circumscribed by the respective envelope of said cross-sectional area. For example, a lever configured as a rod structure can have a cross-sectional area of ​​component 1, with the individual partial surfaces T1 corresponding to the cross-sections through each rod with its varying dimensions. Component 2 can be another rod structure lever connected to this lever, and both levers can interpenetrate in the manner shown by way of example in Fig. 10. Fig. 10 is only intended to illustrate the interpenetration principle of interlocking components, these cross-sectional areas and partial surfaces can also have other consequences depending on the requirements.

[0067] Figure 11 shows two support joints G S via the weighing receiver (not shown) and two linkage joints G R1 shows an example of a linkage Lo configured as a rod structure, which is jointed to a load receiver, also not shown, via a linkage Lo. The rod structure design provides high stiffness in all directions of space at low weight. At the same time, the material-free space between the rods provides space for further components, through which the linkage can be passed. Additionally or alternatively, one or more further components of the weighing block may of course be configured as rod structures according to this example.

[0068] Figure 12(a) shows an example of a half-timbered construction of components formed from individual prisms or penetrated by prism-shaped cutouts. An alternative design can be seen in Figure 12(b), where a rectangular block is penetrated by a spherical cutout. Naturally, such and other design forms (even within each component) can be combined in any way necessary. [Explanation of symbols]

[0069] α Web angle at cross spring joint β Angle between two pivot axes displaced to the intersection 1,2 Components of weighing block (general) A Load Receptor A GL Load joint pivot axis A GR Linkage joint pivot axis A GS Pivot axis of support joint B Weighing block B1, B2 1st / 2nd block ends C Notch D Permanent magnet E1, E2 weighing receiver installation area F Weighing receiver G L Load Joint G R Linkage Joint GS Support Joint H First Lever H1, H2: First / second end regions of lever H K Connecting member L Load Receptor Lo Upper linkage Lu Lower Linkage M Second Lever M1, M2: first / second end regions of lever M P coil Q Position detector Q1, Q2 position detector components T-pocket T1,T2 partial surface V support area V1,V2 envelope X / Y / Z Longitudinal / Horizontal / Height

Claims

1. A weighing block (B) extending in a longitudinal direction (X), a lateral direction (Y) perpendicular to the longitudinal direction (X), and a height direction (Z) perpendicular to both directions (X, Y), the weighing block (B) being: a) a weighbridge (F) for supporting a linkage or lever; b) two said linkages (Lo, Lu), each of said linkages extending in a longitudinal direction (X) from a first end region to a second end region opposite said first end region, each said linkage (Lo, Lu) having at least one support joint (G S ) is connected to the weighing receiver (F) c) a load receiving portion (A) for receiving a weight force introduced along a height direction (Z), both said linkages each having a second end connected to at least one linkage joint (G R a weighing block which is connected to the load receiving part (A) via a load receiving part (B) and whereby the load receiving part (B) is guided parallel to the weighing receiver in a height direction (Z), d) the individual components of the weighing block (B) are constructed in a layer-by-layer manner based on the principles of generative manufacturing (3D printing) and are monolithically connected together; The at least two components (1, 2) of the weighing block are each provided with a plurality of separated partial surfaces (T 1 , T 2 ), and the envelope of both cross sections (V 1 , V 2 ) at least partially overlap, and at least one partial surface of each of the cross sections is located inside the envelope of the other cross section, and the components include the weighing receiver (F), the load receiver (A), the levers (H, M), the connecting element (K), the linkage, the joint (G L , G S , G R ) A weighing block (B).

2. The first end region (H 1 ) and a second end region (H 2 A first lever (H) is provided extending between the first end region (H 1 ) to transmit the force further through the load joint (G L ) and the first lever (H) is connected to at least one of the connecting members (K) including a support joint (G S ) and is connected to the weighing receiver (F) via the support joint (G S ) and the load joint (G L ) are both rotation axes (A GS , A GL 2. The weighing block (B) according to claim 1, characterized in that each of the weighing blocks (B) is formed with a first and a second weights (G1, G2, G3, G4) and a second weights (G5, G6, G7, G8, G9, G10, G11, G12, G13, G14, G15, G16, G17, G18, G19, G20, G21, G22, G23

3. The load joint (G L 3. The weighing block (B) according to claim 2, characterized in that, for connecting two sections of the weighing block to one another, at least two material webs are configured as cross spring joints which jointly connect a first section with a second section, one of the material webs forming an angle (α) with the other material web with 45°≦α≦135° when viewed in projection along the pivot axis.

4. The load joint (G L 4. Weighing block (B) according to claim 3, characterized in that the cross spring joint is arranged on the same lever as the weighing block (B).

5. 5. Weighing block (B) according to claim 2, characterized in that the connecting member (K) has two cross spring joints spaced apart from one another by a material web which transmits further forces.

6. The joint (G) disposed in the linkage (Lo, Lu) S , G R 6. Weighing block (B) according to claim 1, characterized in that the pivot axes of said weighing block (B) are located at the vertices of a parallelogram.

7. At least one of the load joints (G) is connected to the lever (H, M). L ) or the support joint (G S 7. Weighing block (B) according to claim 2, characterized in that the weighing block (B) is surrounded on one or both sides with respect to the direction of its pivot axis by the material area of ​​the lever.

8. 8. Weighing block (B) according to claim 2, characterized in that at least two joints acting on the same lever, whose pivot axes are not aligned in a straight line, are located one behind the other in the direction of the respective pivot axes so that the joint cross sections formed perpendicular to the respective pivot axes overlap when viewed in projection in the direction of the pivot axes.

9. A weighing block (B) according to any one of claims 2 to 8, characterized in that the pivot distance in one direction (X, Y, Z) of two joints connected to the same lever is greater than zero and smaller than the extent of at least one of the joints in said direction.

10. At least one of the levers (H, M) is connected to a first joint (G L 10. Weighing block (B) according to claim 2, characterized in that it has a pocket (T) for accommodating a weighing element (10).

11. The pocket (T) has a wall section (W) from which on one side the first joint (G L ) protrudes from said wall section, and on the other side of said wall section another support section (V) protrudes from said wall section, for connection with another joint (G S 11. Weighing block (B) according to claim 10, characterized in that it protrudes for connection with a weighing block (B).

12. Weighing block (B) according to claim 11, characterized in that both said support sections form a Z-shaped cross section together with said wall section (W).

13. The first end region (M 1 ) and a second end region (M 2 ), and the first end region (M 1 ) at the load joint (G L ) of the first lever (H) via the connecting member (K) having a second end region (H 2 ) and is connected to the support joint (G S A second lever (M) is provided which is connected to the weighing receiver via the support joint (G S ) and the load joint (G L 13. The weighing block (B) according to claim 2, characterized in that each of the first and second arms (12) forms a pivot axis.

14. 14. Weighing block (B) according to claim 2, characterized in that one of the two levers (H, M) has a notch in which a section of the other lever (M, H) is placed.

15. The weighing receiver (F) is arranged in the longitudinal direction (X) starting from the first block end (B1), a) extending between each of the parallel linkages (Lo, Lu), and / or A weighing block (B) according to any one of claims 1 to 14, characterized in that it extends through said load receiving portion (A).

16. 16. The weighing block (B) according to claim 1, characterized in that the load receiving portion (A) and / or the weighing receiver (F) are pierced by a notch extending in the longitudinal direction (X), in which at least one joint is arranged.

17. A weighing block (B) according to any one of claims 1 to 16, characterized in that the levers (H, M) are surrounded on both sides in the lateral direction (Y) by further levers (H, M), which are further surrounded on both sides in the lateral direction (Y) by the weighing receiver (F).

18. The joint (G R , G S , G L 18. The weighing block (B) according to claim 1 , characterized in that the weighing block (B) is configured as a cross spring joint, at least three material webs jointly connect a first section with a second section, at least one of the material webs forming an angle (α) with at least two other material webs in a projection along the pivot axis of 45°≦α≦135°.

19. The lever (H, M) or the joint (G S , G R , G L 19. The weighing block (B) according to claim 1 , characterized in that at least one section of the linkage (Lo, Lu) or the weighing receiver (F) or the load receiving part (A) or the connecting member (K) is configured as a rod structure.

20. 20. A weighing block (B) according to claim 1, characterized in that the cross-sectional area of ​​at least more than 50% of all cross-sections situated through the levers (H, M) perpendicular to the main direction of extension is smaller than the area circumscribed by the envelope of the respective cross-section.

21. 21. Weighing block (B) according to claim 1, characterized in that the pivot axes displaced to the intersection of the two joints form an angle (β≠β0).

22. A component of a weighing block (B) according to any one of claims 1 to 21, which is manufactured based on the principle of generative manufacturing (3D printing), said component being a lever (H, M) or a weighing receiver (F) or a load receiver (A) or a joint (G L , G S , G R ) or linkage (Lo, Lu) or connecting member (K).

23. 22. A method for manufacturing a weighing block (B) according to any one of the claims 1 to 21, in which the individual components are constructed by repeated application of thin material layers one above the other (3D printing).

24. 24. The method of claim 23, characterized in that material shaping with the thin material layer is performed in one of the directions (X, Y, Z).

25. 25. Method according to claim 23 or 24, characterized in that the material shaping of one component of the weighing block is interrupted by the material shaping of at least one other component.

26. A method for manufacturing at least one monolithic component of a weighing block (B) according to any one of claims 1 to 21, comprising generative manufacturing (3D printing) of at least one component, said at least one component being a lever (H, M) and / or a weighing receiver (F) and / or a load receiver (A) and / or a joint (G). L , G S , G R ) and / or linkages (Lo, Lu) or connecting members (K).

27. 22. The weighing block (B) according to any one of claims 1 to 21, characterized in that the weighing block is partially or entirely made of metal.

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