Weighing system with astaxation lever

Abstract

The invention relates to a weighing system (10) comprising - a base (12), - a load sensor (14) which is articulated to the base (12) by means of a parallel link arrangement, - a translation lever (24) pivotably attached to the base (12) by means of a translation lever joint (25), the first translation lever arm (241) of which is connected to the load sensor (14) via a load coupling band (28) and the second translation lever arm (242) of which carries an element of an electromagnetic compensatory sensor arrangement (26), - an astaxation force generating element (42) fixed on one side at the base (12), by means of which an astaxation force can be generated which can be introduced into an introduction point (32) on the force flow path, and - an astaxation lever (36) pivotably attached to the base (12) by means of an astaxation lever joint (40), which is connected to the introduction point (32) at a first coupling point by means of an astaxation coupling band (34) and which is operatively connected to the astaxation force generating element (42) at a second coupling point. The invention is characterized in that the introduction point (32) is rigidly connected to the load receiver (14) and the astaxation coupling band (34) is extended longitudinally in the longitudinal direction (L) of the weighing system (10) and has a different length than each of the parallel links (16a, 16b).

Description

Field of invention

[0001] The invention relates to a weighing system comprising a vertical direction, a longitudinal direction oriented perpendicular to it, and a lateral direction oriented perpendicular to both, comprising - a base, - a load sensor which is articulated at its base by means of a parallel link arrangement comprising two parallel links aligned to each other, spaced apart in the vertical direction and extending longitudinally in the longitudinal direction of the weighing system, - a translation lever pivotally mounted at the base by means of a translation lever joint, the first translation lever arm of which is connected to the load sensor via a load coupling strap and the second translation lever arm of which carries an element of an electromagnetic-compensating sensor arrangement, - an astaxation force generating element fixed on one side at the base, by means of which an astaxation force can be generated that can be introduced into an introduction point located on a force flow path from the load transducer to the sensor arrangement, and - an astaxation lever pivotally attached to the base by means of an astaxation lever joint, which is connected to the introduction point at a first coupling point, which is arranged at a first distance to the astaxation lever joint, by means of an astaxation coupling band, and which is operatively connected to the astaxation force generating element at a second coupling point, which is arranged at a second distance to the astaxation lever joint. State of the art

[0002] Such a weighing system is described in DE 10 2023 132 262 A1.

[0003] Gravimetric measuring devices, i.e., weighing devices, operating on the principle of electromagnetic compensation have long been known to those skilled in the art. For example, EP 2 690 415 A1 discloses such a weighing device.

[0004] The basic principle is that the deflection of a load-bearing device relative to a base, caused by the weight of a load, is transmitted via a lever mechanism to a sensor, which in turn exerts an electromagnetic force on the lever arm that opposes the deflection. This compensating force depends on the current supplied to the coil of a moving-coil assembly that generates the compensating force. If the current is selected such that the load-induced deflection of the lever is exactly compensated, and the lever arm is therefore in its equilibrium position despite the applied load, the compensating current represents a precise measure of the required compensating force and thus of the weight of the applied load.

[0005] Technically, such a system is generally implemented as follows: A parallel link arrangement connects the load cell, to which a weighing device, such as a weighing pan, can be attached, to a fixed base. This ensures that, with correct positioning of the weighing device, its degrees of freedom are limited—at least for small deflections—to a largely vertical, tilt-free movement. The load cell is connected to a transmission lever, specifically to the lever arm on the load cell side, via a coupling band. Here, a coupling band is understood to be a predominantly long, flexible connection, primarily in only one bending direction.A thin strip of sheet metal is often used for this purpose, frequently exhibiting thin spots near its end fixing points. This means that the strip, which is already primarily flexible in one dimension due to its shape, is ultimately articulated at its fixing points. The transmission lever is pivotally mounted on a fixed lever joint, referred to here as the transmission lever joint. This pivot point marks the boundary between the load-sensing lever arm, referred to here as the first transmission lever arm, and the sensor-side lever arm, referred to here as the second transmission lever arm. The coil of a moving-coil assembly is usually fixed at the end of the sensor-side lever arm. It is immersed in the magnetic field of a fixed, usually pot-shaped, magnet, typically a permanent magnet. Reverse arrangements with a fixed coil and a fixed (permanent) magnet are also conceivable but uncommon.The position of the lever in a predefined reference load situation (usually unloaded for conventional scales, loaded for comparators) represents its equilibrium position. This can be detected by a separate position sensor, which typically operates on an optical principle, or the lever can be adjusted so that, in the reference load situation, it is in a position interpreted by the position sensor as equilibrium. When the coil is energized, a magnetic field corresponding to the coil current is generated, which interacts with the magnetic field of the permanent magnet, resulting in a force acting on the lever arm on the sensor side. Conversely, placing a load on the load cell results in a mechanical force acting on the lever arm on the load cell side.By means of a suitable control system, such a device can be operated in such a way that every (infinitesimal) load-induced deflection of the transmission lever is detected by the position sensor and converted into a compensatory change in the coil current. In this way, the transmission lever remains in its equilibrium position (apart from infinitesimal deflections), whereby the current flowing through the coil at the end of a transient process is representative of the load placed on the load cell, the weight of which can be determined with high precision by corresponding measurement of the coil current.

[0006] The mechanical component of this complex system is often referred to in technical jargon as the weighing system. Those skilled in the art will recognize that relative orientation terms relating to the weighing system, such as "above" or "over" and "below" or "under," are to be understood here in the context of the intended alignment of the weighing system within a functioning scale. The same applies to terms such as the "vertical direction" of the weighing system, i.e., the vertical direction or direction of action of gravity; the "longitudinal direction" of the weighing system, i.e., the horizontal direction or principal direction of distance between the load cell and the base, or the longitudinal extension direction of the parallel links; and the "lateral direction" of the weighing system, i.e., the direction perpendicular to the two aforementioned.

[0007] Modern weighing systems are highly precision-manufactured, often monolithic devices that, despite the use of advanced precision technology, can exhibit deviations from an ideal system. In particular, the so-called stiffness of the joints in such a weighing system represents one such deviation. Stiffness refers to the restoring force that a real joint (as opposed to an ideal joint) exerts against its deflection. It is generally not possible to define the equilibrium position of the lever as the position in which the lever joint is exactly at rest, i.e., in which no stiffness-related torque acts. Instead, a slightly different lever position is usually defined as the equilibrium position using the position sensor. A possibleThe coil current required to maintain this equilibrium position against a stiffness-induced torque in the moving-coil arrangement is subsequently treated as the offset current. This process is referred to as "taring" the balance. However, a further deviation from the ideal system lies in the finite resolution with which the position sensor can detect the position of the transmission lever, particularly its equilibrium position. A deviation from the defined equilibrium position below this resolution limit therefore leads to a stiffness-induced torque that is not compensated by taring and adds—positively or negatively—to the torque caused by the weight of the item being weighed. The magnitude of this "error" torque—given a specific positional deviation of the transmission lever—depends on the actual joint stiffness. This is known as...Astasing aims to minimize the slope of this essentially linear dependence, so that the inevitable real deviations from the defined equilibrium position due to the finite position sensor resolution result in the lowest possible error torque.

[0008] Various stabilizing devices are known to those skilled in the art. One known stabilizing device is to design the transmission lever such that its center of gravity lies above the lever joint, i.e., above its exact pivot axis. This leads to an instability of the equilibrium position of the transmission lever. Any deflection of the lever, due to its elevated center of gravity, results in a torque that amplifies the deflection. This torque counteracts the inverse stiffness torque of the lever joint. Conversely, stabilization can be achieved by shifting the lever's center of gravity below its pivot axis. A disadvantage of this approach is that both the joint stiffness and the center of gravity of the lever are subject to manufacturing variations and therefore only very rarely compensate for each other perfectly. Furthermore, the system exhibits increased susceptibility to tilting.

[0009] A similar principle, known from EP 0 359 978 B1, produces a similar result but is less prone to tipping. In this principle, the transmission lever has a coupling point above its lever joint for one end of a tension spring, the other end of which is fixed at the base, so that the tension spring is stretched vertically across the transmission lever joint. This exerts a force on the transmission lever, acting vertically from top to bottom and passing through the transmission lever joint. This force is introduced into the transmission lever via the spring coupling point, which acts as the introduction point for the astaxation force. The mechanical implementation of this principle, still considered extremely advantageous, as revealed in this approximately 35-year-old publication, is no longer compatible with modern, extremely high-resolution scales.In particular, it would be desirable to reduce the force acting on the transmission lever joint in the equilibrium position in order to prevent material creep in the area of ​​the joint, which is typically designed as an extremely delicate thin section. Furthermore, the direction of action of the spring force of the tension spring, designed as a helical spring, cannot be reproduced with sufficient precision to ensure that it always passes exactly through the pivot axis of the transmission lever, which would be necessary for high-resolution, modern scales.

[0010] The aforementioned, generic German patent application DE 10 2023 132 262 A1 addresses this problem and solves it by not attaching the spring, which can be described as an astaxation spring, directly to the transmission lever, but only indirectly via an astaxation lever pivoted at its base and an astaxation coupling band fixed to it. The point of application of the astaxation force and the (vertical) direction of this force application remain unchanged compared to the aforementioned design. The point of application, which is rigidly connected to the lever and located directly above the transmission lever joint, is subject to pivoting movements during operation of the weighing system. The astaxation coupling band experiences corresponding bending movements with corresponding energy absorption at the bending points, i.e., particularly at thin-section joints of the coupling band. This has proven disadvantageous in the context of the design of extremely high-resolution scales.

[0011] From DE 10 2021 132 094 B3, a weighing system is known with two parallel transmission levers attached to the load sensor, each coupled to a moving-coil assembly. The two transmission levers have different, in particular opposite, astasing. By appropriately controlling the moving-coil assemblies, it is possible to distribute the force flow between the two transmission levers in such a way that optimal astasing is achieved for the overall force flow. This design is very complex, expensive, and space-consuming, especially due to the double moving-coil assembly.

[0012] From DE 1 238 229 A, a purely mechanical scale is known in which the vertical load cell is connected to a base in a parallelogram-like fashion via a lower link and an upper link, which simultaneously acts as a transmission lever with a counterweight. The load cell is biased against the base by means of a vertically oriented tare spring. It is also biased against the base by means of a horizontally oriented compensation spring arranged vertically between the links. The compensation spring is longer than the horizontal distance between the load cell and the base-side bearing points of its links. When the compensation spring is in a precisely horizontal position, its tensile force is supported by the lower link.However, when the load sensor deflects, the compensation spring, which is no longer perfectly horizontal, exerts a torque around the base-side pivot point of the lower link. The vertical component of this torque acts on the load sensor in the direction of the deflection. With correct adjustment of the compensation spring, this is intended to compensate for changes in the spring constant of the counterweight spring that occur due to its non-ideal, real-world properties during deflection. Task

[0013] The object of the present invention is to further develop a weighing system of the generic type in such a way that the astaxation coupling belt is subject to a lower energy absorption due to movement. Description of the invention

[0014] This problem is solved in conjunction with the features of the preamble of claim 1 by the fact that the introduction point is rigidly connected to the load sensor and the astasing coupling band is extended longitudinally in the longitudinal direction of the weighing system and has a different length than each of the parallel links.

[0015] Preferred embodiments are the subject of the dependent claims.

[0016] The basic idea of ​​the invention lies in relocating the point of application for the astaxation force from the transmission lever to the load cell. The linear movements of the load cell during operation are significantly smaller than the pivoting movements of the transmission lever, whose primary function is precisely to amplify the minimal movements of the load cell in order to measure them with high resolution. For the fundamental effectiveness of the astaxation force—namely, as an additive contribution to the measured weight force in the case of destabilizing astaxation, or as a subtractive contribution to the measured weight force in the case of stabilizing astaxation—its specific point of application is irrelevant. However, the point of application does play a significant role with regard to minimizing the bending stress on the astaxation coupling band, through which the astaxation force is introduced.The inventive choice of the introduction point on the load cell thus reduces the bending stress on the astaxation coupling band, which is recognized as disadvantageous, without impairing the fundamental operating principle of astaxation.

[0017] However, the geometric consequences arising from the relocation of the application point are problematic with regard to force transmission. In the unloaded equilibrium state, no (astaxation) force should act on the load cell or the downstream force flow path; in the deflected state, however, precisely the astaxation force compensating for the joint stiffness should act, specifically, when introduced at an application point located on the load cell itself, in or against the direction of the gravitational force. The vertical orientation of the astaxation coupling band described in the prior art cannot therefore be maintained with the relocation of the application point according to the invention, as this would lead to a force acting continuously, i.e., even in the unloaded equilibrium state.

[0018] According to the invention, the astaxation coupling band is therefore designed to extend longitudinally in the direction of the weighing system, i.e., essentially horizontally or perpendicular to the direction of movement of the load cell, or parallel to the parallel links in their unloaded equilibrium position. The latter description, in particular, represents the functional core of this feature. At the same time, the astaxation coupling band must have a different length than the (typically equally long) parallel links. In the equilibrium position, especially when the parallel links are aligned exactly horizontally, the astaxation coupling band runs exactly parallel to the parallel links and, in particular, also exactly horizontally. A force introduced via the astaxation coupling band into the point of application of the load cell is thus aligned exactly perpendicular to the load cell or to the direction of gravity.Therefore, no astaxating force acting in or against the direction of gravity acts on the load cell. Any force applied perpendicular to it is supported by the parallel links. However, if the load cell deflects (due to the load), the parallel links and the astaxating coupling band are no longer parallel to each other due to their different lengths. Furthermore, neither is exactly perpendicular to the gravitational force. A tensile force exerted on the astaxating coupling band by the astaxating force-generating element via the astaxating lever can then no longer be fully supported by the parallel links and therefore results in a vertical force component on the load cell, namely the desired astaxating force. Its magnitude can be appropriately selected by suitable design of the components involved, e.g.,...by choosing the strength and / or direction of force action of the astaxation force-generating element, the length ratio of the astaxation coupling band and parallel links, their positioning, etc.

[0019] Particularly if the anti-static coupling band is longer than either of the parallel control arms, a destabilizing anti-static effect results. This will be desirable in most cases. If a stabilizing anti-static effect is desired, the anti-static coupling band can be made shorter than the parallel control arms.

[0020] Both variants with a (functionally) two-armed astaxation lever and variants with a (functionally) single-armed astaxation lever are conceivable. In the former variant, this means that the astaxation lever has two astaxation lever arms arranged on opposite sides of the astaxation lever joint. The first of these is connected to the introduction point via the astaxation coupling band, and the second is operatively connected to the astaxation force-generating element. In other words, the first and second coupling points are located on opposite sides of the astaxation lever joint, or on different astaxation lever arms of the astaxation lever. The magnitudes of the first and second distances, i.e., the distance of the first and second coupling points from the astaxation lever joint, can be the same or different.In the second variant, both coupling points are arranged on the same pivot arm of the pivot lever. Preferably, the first and second distances, i.e., the distances of the first and second coupling points from the pivot lever joint, are different. This describes both structurally true single-arm designs of the pivot lever and those in which the pivot lever, although structurally extending on both sides of the pivot lever joint, is functionally used only on one side, i.e., as a single-arm lever. Designs in which the first and second distances are equal are also conceivable.

[0021] For reasons of installation space, the inlet point and the astaxation coupling band are preferably arranged vertically between the parallel links of the weighing system. However, it is also conceivable to position the inlet point and the astaxation coupling band above or below the parallel link assembly.

[0022] The astax lever is preferably extended longitudinally in the vertical direction of the weighing system. That is, it is essentially perpendicular to the astax coupling belt, or, in other words, essentially vertical. In such a position, an astax force introduced into the second astax lever arm, namely the force generated by the astax force generating element, is introduced into the astax coupling belt with maximum transmission. The same applies to the equally preferred embodiment of an astax lever extending longitudinally in the horizontal direction. This can, in particular, be arranged completely and in a space-saving manner vertically between the parallel links.

[0023] In contrast, a maximum transmission of the astaxation force is not guaranteed in an inclined arrangement. Such a transmission may nevertheless be desirable. If the astaxation lever, as provided in an alternative embodiment, is extended longitudinally at an angle to the vertical and / or horizontal direction of the weighing system, the distance spanned by the astaxation coupling band can be increased, particularly if the first coupling point is further away from the load sensor than the second coupling point. This allows the length of the astaxation coupling band to be increased in a space-saving manner. The effects on the adjustment of the resulting astaxation force acting on the load sensor arise from geometric considerations.

[0024] To further increase the length of the astaxation coupling band, the entry point can alternatively or additionally be arranged on a projection extending towards the side of the load cell facing away from the base. However, the functionally significant factor here is not so much the relationship of the projection to the base, but rather its relationship to the fixing point of the astaxation coupling band on the first astaxation lever arm, i.e., to the first coupling point.

[0025] The astaxant force-generating element is preferably designed as a spring, in particular as a tension spring. The first end of the spring is fixed at the base, preferably on the side of the astaxant lever facing the load-bearing device, and its second end is fixed at the second coupling point. This fixing can be a linkage. However, the spring will generally be sufficiently flexible to compensate for the minute deviations from a purely linear movement of the second coupling point that occur during the expected small deflections of the astaxant lever. At the other, first coupling point, compensation is achieved by the properties of the coupling strap, whose flexibility is precisely defined or limited by its shape.

[0026] The coupling band is preferably flexible primarily in the vertical direction, i.e., about bending axes aligned in the width direction of the weighing system. However, to compensate for manufacturing tolerances regarding the exact alignment of its connections to the entry point on the one hand and the coupling points on the astaxation lever on the other, a section of the astaxation coupling band is preferably designed as a decoupling thin section with reduced thickness and / or width. In this area, the coupling band exhibits increased flexibility in the width direction of the weighing system, i.e., about vertical bending axes.

[0027] Advantageously, the strength of the astaxation force is adjustable. This can be achieved, for example, by making the fixed position of the spring at the base adjustable relative to the base in the direction of the spring's force.

[0028] Further adjustment options are also considered advantageous in order to influence the geometric relationships and thus precisely adjust the resulting astaxation force. This allows even the smallest manufacturing tolerances to be compensated for, enabling access to resolution levels previously unattainable in weighing technology. Therefore, it appears advantageous to design at least one of the following elements to be adjustable: - the point of entry relative to the load sensor, specifically in the vertical direction of the weighing system, - the astaxing lever joint together with the astaxing lever relative to the base, namely in the vertical and / or longitudinal direction of the weighing system, - the first coupling point relative to the astaxation lever, specifically in its longitudinal direction, - the second coupling point relative to the astaxation lever (36), specifically in its longitudinal direction, and / or - as mentioned above, a fixed position of the spring at the base relative to the base, namely in the direction of force exerted by the spring.

[0029] Further details and advantages of the invention will become apparent from the following specific description and the drawings. Brief description of the drawings

[0030] They show: Fig. 1: a highly schematic representation of a first embodiment of a weighing system according to the invention with a two-armed astaxation lever, Fig. 2: a highly schematic representation of a second embodiment of a weighing system according to the invention with a single-arm aspiration lever, Fig. 3: a highly schematic representation of a third embodiment of a weighing system according to the invention with an inclined, two-armed astation lever, Fig. 4: a highly schematic representation of a fourth embodiment of a weighing system according to the invention with an inclined, single-arm aspiration lever, Fig. 5: a highly schematic representation of a fifth embodiment of a weighing system according to the invention with a forward-extended astaxation coupling belt as well as Fig. 6: a two-part functional diagram to illustrate the operating principle according to the invention. Description of preferred embodiments

[0031] Identical reference symbols in the figures indicate identical or analogous elements.

[0032] Fig. Figure 1 shows a highly schematic side view of a weighing system 10 according to the invention in a first embodiment. The base 12 of the weighing system 10, often referred to in technical jargon as the "main" or "system support," is only indicated in the figures. The weighing system 10 has a Roberval mechanism by means of which a load cell 14 is articulated to the base 12 via two parallel links 16a, 16b. Both parallel links 16a, 16b are articulated on one side to the base 12 and on the other side to the load cell 14 by means of joints, here referred to as Roberval joints 18, which are preferably designed as thin sections of material. The load cell 14 is connected to a load carrier 20, this connection being effected in the illustrated embodiment via a cantilever arm 22.

[0033] Furthermore, the weighing system 10 has a transmission lever 24, which is composed of a first transmission lever arm 241 on the load-sensing side and a second transmission lever arm 242 on the base side. The boundary between the first and second transmission lever arms 241, 242 is located in the longitudinal direction of the transmission lever 24 at the level of a transmission lever joint 25, which is preferably designed as a thin section of material and by means of which the transmission lever 24 is pivotally articulated to the base 12. At its free end, the second transmission lever arm 242 carries components of a sensor arrangement 26. In the illustrated case, this is, firstly, the moving coil 261 of an electromagnetically compensating sensor which also includes a base-fixed pot magnet 262. Furthermore, the second transmission lever arm 242 carries the target 263 of an optical position sensor, which is not shown.

[0034] The free end of the first transmission lever arm 241 is connected to the load receiver 14 via a load coupling band 28. In particular, the load coupling band 28 can consist of a sheet metal strip which has a coupling band joint 30 designed as a thinning point of material near each of its two ends.

[0035] In this respect, the weighing system according to the invention does not differ from known weighing systems for electromagnetically compensated scales (EMF scales) and also corresponds to them with regard to its basic functionality. A load placed on the weighing carrier 20 exerts a weight force on the load sensor 14, which tends to deflect vertically downwards to avoid this force. The force, or the resulting deflection, is transmitted via the load coupling band 28 to the transmission lever 24, whose first transmission lever arm 241 tends to be pulled downwards and whose second transmission lever arm 242 tends to be pushed upwards. The deflection is detected by the optical position detector, and the coil 261 of the sensor 26 is energized with precisely the amount necessary to completely suppress the deflection and hold the transmission lever 24 in its equilibrium position after a settling-in period.The compensation current through coil 261 required for this purpose is representative of the weight force exerted by the item being weighed.

[0036] The special feature of the present invention relates to the specific way in which an astaxation force is introduced.

[0037] In the vertical direction H between the parallel links 16a, 16b, i.e., below the upper parallel link 16a and above the lower parallel link 16b, an entry point 32 is located on the load-bearing element 14. The entry point 32 is characterized, firstly, by being rigidly connected to the load-bearing element 14 and, secondly, by having means for fixing an anti-static coupling band 34 there. This fixing can be a pivot point. Usually, however, it is a clamp or a one-piece, particularly monolithic, design. Particularly in cases where the anti-static coupling band is rigidly fixed to the entry point 32, it has a coupling band joint 38 located near its end, which is preferably designed as a thin section of material. The anti-static coupling band 34 extends horizontally, i.e.,The astaxing coupling band 34 extends along the longitudinal direction L of the weighing system 10 and is fixed at its end furthest from the load sensor to a first astaxing lever arm 361 of an astaxing lever 36. This fixing point is also referred to here as the first coupling point. The fixing can be either a pivot or a rigid fixation, in the latter case also allowing for a coupling band joint 38 near the end. The astaxing coupling band 34 is suitable for transmitting tensile forces between the load sensor 14 and the astaxing lever 36. Due to its band shape, it is bendable, particularly in the vertical direction H. Perpendicular to this, i.e., in the lateral direction of the weighing system 10, it is virtually inflexible, at least over the majority of its length. However, in the illustrated embodiment, a decoupling thin section 341 is provided in the central region of the astaxing coupling band 34, at which the coupling band is also bendable in the lateral direction.This end decoupling thinness 341 serves to compensate for any offset in width between the introduction point 32 and the first coupling point that may be caused by manufacturing or assembly.

[0038] The static lever 36 is pivotally connected to the base 12 by means of an static lever joint 40. The second static lever arm 362 is connected at its free end to an static force-generating element 42, which here is specifically designed as a spring 420, in particular as a tension spring. This pivot point is also referred to here as the second coupling point. The end of the spring 420 furthest from the lever is fixed to the base 12. Thus, by means of the spring 420, a tensile force, which is translated and redirected by the static lever 36 and transmitted by means of the static coupling band 34, can be applied to the load-bearing device 14, in particular to its application point 32. In the Fig. In the equilibrium state shown in Figure 1, in which the stabilizing coupling band 34 runs exactly horizontally and parallel to the parallel links 16a, 16b, this tensile force is completely supported by the parallel links 16a, 16b, so that no deflecting force acts on the load-bearing element 14. The deliberately different lengths of the parallel links 16a, 16b on the one hand and the stabilizing coupling band 34 on the other have no effect in this equilibrium position. In the illustrated embodiment, the stabilizing coupling band 24 is, in particular, longer than each of the parallel links 16a, 16b.

[0039] The in Fig. The equilibrium position shown in Figure 1 is represented in the even more schematic functional diagram of Fig. 6a is shown again in solid lines. Furthermore, in Fig. Figure 6a shows the (highly exaggerated) situation of a deflection of the load cell 14, as can occur in particular when a load to be weighed is placed on the weighing platform 20. For this purpose, in Fig. 6a dotted lines are used. The deflection of the load-bearing device 14 is caused by its linkage to the base 12 by means of two parallel links 16a, 16b, of which in Fig. Figure 6a shows only one, without tilting. In addition to a vertical movement component, the finite length of the parallel links 16a, 16b also results in a slight offset in the longitudinal direction L, which, however, does not play a significant role here. What is crucial for the functional principle of the present invention is that, due to the different lengths of the parallel links 16a, 16b on the one hand and the stabilizing coupling band 34 on the other, a loss of parallelism occurs between the two in the deflected state, a parallelism that was still present in the equilibrium state. To illustrate this, Figure 6a shows... Fig. 6b shows the deflected position with the parallel link 16b offset vertically upwards for illustrative purposes. In particular, the deflected parallel link 16b was offset to the same height as the deflected astaxation coupling band 34. In this representation, it is easy to see that the two are no longer parallel to each other.

[0040] A tensile force exerted by the spring 420 via the antistatic lever 36 and the antistatic coupling band 34 on the load-bearing device 14 is therefore no longer fully supported by the parallel links 16a, 16b, but instead results in a torque around the pivot point of the parallel link 16b at the base 12, i.e., around the Roberval joint 18. The vertical force component of this torque corresponds to a vertical force directed in the direction of deflection of the load-bearing device 14. This is the desired, destabilizing antistatic force, which occurs exclusively in the deflected state and is dependent on, and in particular essentially proportional to, the current deflection.In a hypothetical case, not shown here, in which the astaxating coupling band 34 is shorter than the parallel links 16a, 16b, or in the case that the spring 420 was designed as a compression spring or as a tension spring on the opposite side of the astaxating lever 36, a stabilizing astaxating force would occur.

[0041] Fig. Figure 2 shows a similar variant with a single-armed astaxing lever 36. Here, the spring 420 and the astaxing coupling band 34 act on the same (single) arm of the astaxing lever (36). Accordingly, the spring 420 must act in the opposite direction.

[0042] The greater the difference in length between the astaxation coupling band 34 on the one hand and the parallel links 16a, 16b on the other, the stronger the resulting astaxation force for a given deflection of the load-bearing device 14. Fig. 3, Fig. 4 to Fig. Figure 5 schematically shows further embodiments in which the astaxation coupling band 34 differs from the embodiments of the Fig. 1 and Fig. 2 is extended without changing the geometry of the rest of the weighing system 10. Both approaches shown for extending the astasing coupling belt 34 can be implemented individually or in combination.

[0043] In the embodiment of Fig. 3 The two-armed astatic lever 36 is arranged at an angle, with its second astatic lever arm being located further towards the load-sensing device than its first astatic lever arm 361. The resulting extension of the astatic coupling band 34 is obvious. Fig. Figure 4 shows a similar variant with a single-armed astaxing lever 36. Here, the spring 420 and the astaxing coupling band 34 act on the same (single) arm of the astaxing lever (36).

[0044] Fig.Figure 5 shows a variant in which the entry point 32 is arranged on a forward-projecting projection 141 of the load cell 14, i.e., extending away from the base 12. In such an embodiment, the astaxation coupling band 34 must cross the load cell 14, which can be achieved, for example, by a corresponding opening in the load cell 14. This variant can also be implemented with a single-arm astaxation lever 36.

[0045] For the sake of simplicity, embodiments in which the astasis lever 36 is longitudinally extended in the width direction or at least inclined (also) to the width direction of the weighing system 10 have been omitted here. However, those skilled in the art will easily be able to deduce such variants from the present disclosure.

[0046] Of course, the embodiments discussed in the detailed description and shown in the figures represent only illustrative examples of the present invention. In light of this disclosure, a wide range of variations is available to those skilled in the art. In particular, variants are conceivable in which the spring 42 is designed as a compression spring instead of a tension spring and / or acts in the opposite direction on the second astaxation lever arm 362. This allows those skilled in the art to generate the desired positive or negative astaxation in each individual case. With regard to the specific mechanics of any adjustability of the entry point 32, all known and potentially yet-to-be-developed precision mechanical implementations are also available to those skilled in the art. Reference symbol list 10 weighing system 12 base 14 load cells 141 lead 16a upper parallel link 16b lower parallel link 18 Roberval joint 20 weighing carriers 22 Cantilever 24 translation levers 241 first translation lever arm 242 second translation lever arm 25 Translation lever joint 26 Sensor arrangement 261 Moving coil 262 Pot magnet 263 Target 28 Load coupling strap 30 coupling ligament joint 32. Introductory point 34 Astaxation coupling band 341 Decoupling thin spot 36 Astatic levers 361 first astaxation lever arm 362 second astaxation lever arm 38 Coupling ligament joint 40 Astaxating lever joint 42 Astatic force generating element 420 spring H Altitude direction from 10 L Longitudinal direction of 10

Claims

[1] Weighing system (10) comprising a vertical direction (H), a longitudinal direction (L) oriented perpendicular to it and a lateral direction oriented perpendicular to both, comprising - a base (12), - a load sensor (14) which is articulated at the base (12) by means of a parallel link arrangement comprising two parallel links (16a, 16b) aligned to each other, spaced apart in the vertical direction and extending longitudinally (L) in the longitudinal direction (L) of the weighing system (10), - a translation lever (24) pivotably attached to the base (12) by means of a translation lever joint (25), the first translation lever arm (241) of which is connected to the load sensor (14) via a load coupling band (28) and the second translation lever arm (242) of which carries an element of an electromagnetic compensatory sensor arrangement (26), - an astaxation force generating element (42) fixed on one side at the base (12), by means of which an astaxation force can be generated which can be introduced into an introduction point (32) located on a force flow path from the load transducer (14) to the sensor arrangement (26), and - an astaxation lever (36) pivotably connected to the base (12) by means of an astaxation lever joint (40), which is connected to the introduction point (32) at a first coupling point, which is arranged at a first distance to the astaxation lever joint (40), by means of an astaxation coupling band (34), and which is operatively connected to the astaxation force generating element (42) at a second coupling point, which is arranged at a second distance to the astaxation lever joint (40), characterized by, that the introduction point (32) is rigidly connected to the load sensor (14) and the astaxation coupling band (34) is longitudinally extended in the longitudinal direction (L) of the weighing system (10) and has a different length than each of the parallel links (16a, 16b). [2] Weighing system (10) according to claim 1, characterized by , that the astaxation coupling band (34) has a greater length than each of the parallel links (16a, 16b). [3] Weighing system (10) according to any one of the preceding claims, characterized by , that the astaxation lever (36) has two astaxation lever arms (361, 362) arranged on different sides of the astaxation lever joint (40), the first astaxation lever arm (361) of which is connected to the introduction point (32) by means of the astaxation coupling band (34) and the second astaxation lever arm (362) of which is operatively connected to the astaxation force generating element (42). [4] Weighing system (10) according to one of claims 1 to 2, characterized by, that both coupling points are arranged on the same astaxation lever arm of the astaxation lever (36), wherein the first and second distances are different. [5] Weighing system (10) according to any one of the preceding claims, characterized by , that the introduction point (32) and the astaxation coupling band (34) are arranged in the vertical direction (H) of the weighing system (10) between the parallel links (16a, 16b). [6] Weighing system (10) according to any one of the preceding claims, characterized by , that the astaxation lever (36) is longitudinally extended in the vertical direction (H) of the weighing system (10). [7] Weighing system (10) according to any one of claims 1 to 5, characterized by , that the astaxation lever (36) is longitudinally extended in the width direction of the weighing system (10). [8] Weighing system (10) according to any one of claims 1 to 5, characterized by , that the astaxation lever (36) is extended longitudinally at an angle to the vertical direction (H) and / or to the horizontal direction of the weighing system (10). [9] Weighing system (10) according to claim 8, characterized by , that the first coupling point is further away from the load receiver (14) than the second coupling point. [10] Weighing system (10) according to any one of the preceding claims, characterized by , that the introduction point (32) is arranged on a projection (141) extending towards the side of the load cell (14) facing away from the base. [11] Weighing system (10) according to any one of the preceding claims, characterized by , that the astaxation force generating element (42) is designed as a spring (420) whose first end is fixed to the base (12) and whose second end is fixed to the second astaxation lever arm (362). [12] Weighing system (10) according to claim 11, characterized by , that the spring (420) is designed as a tension spring. [13] Weighing system (10) according to one of claims 11 to 12, characterized by , that the spring (420) is fixed on the side of the astaxing lever (36) facing the load receiver (14) at the base (12). [14] Weighing system (10) according to any one of the preceding claims, characterized by , that the strength of the astaxation force is adjustable. [15] Weighing system (10) according to any one of claims 11 to 13 or according to claim 14, insofar as it relates back to claim 11, characterized by , that at least one of the following elements is adjustable, namely: - the introduction point (32) relative to the load sensor (14), namely in the vertical direction (H) of the weighing system (10), - the astaxing lever joint (40) together with the astaxing lever (36) relative to the base (12), namely in the vertical direction (H) and / or in the longitudinal direction (L) of the weighing system (10), - the first coupling point relative to the astaxation lever (36), namely in its longitudinal extension direction, - the second coupling point relative to the astaxation lever (36), namely in its longitudinal direction, - a fixing position of the spring (420) at the base (12) relative to the base (12), namely in the direction of force action of the spring (420).

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