Cantilever arm for receiving and measuring variable loads

Abstract

A cantilever arm (1, 20, 25, 40, 50, 60, 70) capable of being fixed at one end to an object, the cantilever arm comprising a resilient material and designed to receive a variable load (4), having a flat body (11) arranged with a surface adjusted vertically in operation, the cantilever arm having, in the operating position, a height (v) defined by an upper end region (6) and a lower end region (7), and a fixed side region (2) for fixing the cantilever arm (1, 20, 25, 40, 50, 60, 70) to the object. and on the other hand by its opposite cantilevered region (8), the cantilever arms (1, 20, 25, 40, 50, 60, 70) further comprising a force application device designed to support a load (4), the flat body (11) of the cantilever arms (1, 20, 25, 40, 50, 60, 70) comprising a deformation opening (10) and a connection device for a deformation sensor for measuring the deformation of the cantilever arms under the current load (4). The deformed opening (10) is formed by the flat body (11), penetrates the flat body, and is completely surrounded by the flat body, all edge areas of the deformed opening are in the plane of the flat body (11), the deformed opening has a horizontal extension (h) defined by the fixed side region (2) and the cantilever side region (8), and a vertical extension (v) defined by the upper end region and the lower end region, and under each current load (4), The cantilever arm (1, 20, 25, 40, 50, 60, 70) is configured to deform in a predetermined manner in response to a force applied thereto, the force application assembly being formed by the body (11) of the cantilever arm (1, 20, 25, 40, 50, 60, 70) and designed such that, in the operating position of the cantilever arm (1, 20, 25, 40, 50, 60, 70, at least a portion of the load (4) is introduced into the cantilever region (8), and the connection device is designed to clamp the deformation sensor between the fixed region (2) and the cantilever region (8) and to enable the sensor to be operational. The cantilever arm (1, 20, 25, 40, 50, 60, 70) is simple in design, inexpensive to manufacture, and allows for highly accurate measurement of a variable load (4) using a deformation sensor (35).

Description

[Technical Field]

[0001] The invention relates to a cantilever arm according to the preamble of claim 1 and to a frame according to the preamble of claim 18 comprising said cantilever arm.

[0002] From WO 02 / 025230 it is known to manage a warehouse of goods by storing or temporarily storing the goods in a storage area and determining the number of goods by weight. Likewise, product variations can be detected through the resulting changes in weight and automatically processed in the warehouse accounting. The weight of the goods is measured by scales or load cells installed in the storage area.

[0003] For example, for storage, it is convenient to use a frame with spaced vertical supports between which a number of shelves are mounted. Scales are then placed on the supports to provide support for the shelves, e.g., one shelf is supported on each side by a scale. Product variation is indicated by the change in weight recorded by the scales, the sum of the weight changes on both scales indicates the weight caused by the variation, and the ratio of the weight changes indicates the position on the shelf where the variation occurred.

[0004] EP 3845873 discloses a cantilever arm suitable for such a frame, which can be simply hooked onto the vertical support of the frame and, in a manner known per se, forms a support for a shelf on which items are placed. The shelf does not rest on the cantilever arm along its length (and depth), as is common in such frames, but only at its corners, and even at the corners, not on the body of the cantilever arm itself, but on a special force-applying portion of the cantilever arm that is reversibly arranged so as to be movable relative to the body of the cantilever arm. The reversible relative displacement causes deformation of the joint between the force-applying portion and the body of the cantilever arm, and a horizontally folded weighing portion of the joint is equipped with a strain gauge, the deformation signal of which is used to calculate the weight on the surface of the shelf. The change in weight can then be evaluated in the manner described in WO 02 / 025230, allowing the position of the displaced item to be determined.

[0005] EP 3845874 represents a further development of the type of cantilever arm disclosed in EP '873, in which a cantilever arm is made with "integrated weighing functionality" and further "is intended to specifically allow for the ability for a load cell to be incorporated into the shelf support or cantilever arm."

[0006] For this purpose, an "integral measuring body" is provided, which is designed as an additional cantilever arm, each with a force-applying portion, a joint portion, and a fixed portion. The cantilever arm fixed to the frame is provided with another cantilever arm, whose fixed portion is fixed to the main body of the cantilever arm fixed to the frame, so that the force-applying portion of the other cantilever arm can support the shelf. As a result, the joint portion of the other cantilever arm deforms in response to the weight applied by the shelf. This deformation is detected by four strain gauges placed at the joint portion, and the desired weight signal is generated by the evaluation electronics using a Wheatstone bridge.

[0007] The drawbacks of the disclosed device with nested cantilever arms are that it is a relatively complex structure, which makes the structure complex and expensive, and when used in a frame, for example as a shelf holder, it has large lateral dimensions.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a cantilever arm that is simple in structure and inexpensive to manufacture, which can be used to reliably detect even relatively small weight changes.

[0009] This object is achieved by a cantilever arm having the features of claim 1 or a frame having the features of claim 17.

[0010] The cantilever arm according to the present invention includes a force application device, a deformation opening, a connection device for connection to a deformation sensor (also referred to simply as a "force sensor"), and a force application device. Its flat design allows it to be manufactured in the simplest and most cost-effective manner, e.g., by stamping from a metal plate, and used without further shaping. Its lateral volume is as small as possible, which is useful, for example, when using the cantilever arm to build a storage frame, thereby maximizing storage space. The deformation opening is located in the flat body itself and has a horizontal extension, so that a relative displacement of the deformation opening's side edges, which are located in the plane of the flat body of the cantilever arm and horizontally spaced apart from one another, occurs under variable loads. This displacement is a measure of the weight of the load present and is perfectly detectable by conventional deformation sensors, since its value lies within the operating range of conventional deformation sensors. The deformation signal of the deformation sensor can be easily recorded and evaluated by evaluation electronics commonly known to those skilled in the art. In addition to the aforementioned challenges, the modified aperture allows for easy installation of a vibrating wire sensor, which is particularly suitable for measuring smallest differences in current load with high precision without long-term drift, without increasing the manufacturing effort or size of the cantilever arm. Further preferred embodiments have the features of the dependent claims.

[0011] The present invention will now be described in more detail with reference to the drawings. especially: FIG. 1 shows a side view of a cantilever arm according to the invention in a basic configuration; FIG. 2 shows an embodiment of a cantilever arm according to the invention with a modified connection device; FIG. 3 shows an embodiment of a cantilever arm according to the invention with a further modified connection device; FIG. 4 shows an embodiment of a cantilever arm according to the invention, equipped with a deformation sensor; FIG. 5 shows an embodiment of a cantilever arm according to the invention, in which the force application device is modified; FIG. 6 shows an embodiment of a cantilever arm according to the invention with a further modified force applicator; FIG. 7 shows an embodiment of a cantilever arm according to the present invention with a distortion correction aperture. FIG. 8 shows an embodiment of a cantilever arm according to the present invention with two distortion correction openings; FIG. 9 shows the deformation of a cantilever arm according to the invention, according to a simulation. FIG. 10 shows an embodiment of a cantilever arm according to the invention, with a reinforcing rib; FIG. 11 shows an embodiment with reinforcing ribs in a front view; and FIG. 12 shows a further embodiment of a cantilever arm according to the present invention.

[0012] FIG. 1 shows a side view of one embodiment of a cantilever arm 1 according to the present invention in its basic configuration. The cantilever arm 1 has a flat body 11 made of a resilient material, stamped, for example, from a 1-3 mm, or even 4 mm, thick metal plate, the outline of which is shown in the figure. Those skilled in the art can select a different thickness of metal plate suitable for the intended maximum load. The illustrated cantilever arm 1 can be used in particular with known, widely used storage frames with vertical support posts. For this purpose, it is provided with a fixed side region 2 with a hook 3 that can be inserted into a corresponding slot in the support post, as is commonly known. However, the fixed side region 2 can be modified by those skilled in the art in specific cases to be operatively attached to any other object (other than a vertical support post), i.e., to be placed in a vertical position.

[0013] The illustrated cantilever arm 1 is designed to be fixed on one side to a vertical post or other object and to project free on the other side. In the operating or fixed position, the cantilever arm 1 is arranged with its surface facing vertically, and the plane of FIG. 1 faces vertically. The cantilever arm 1 can support a vertical downward load 4, such as when items are loaded onto a shelf that is placed on the cantilever arm 1 in a known manner. The load varies depending on the type and number of items to be loaded onto the shelf. Methods for securely fastening a suitably designed shelf into a recess 5 are well known to those skilled in the art.

[0014] In the coordinate system shown in Figure 1, y represents the height, x represents the horizontal extent, and z represents the thickness of the cantilever arm 1, where z projects vertically out of the plane of the drawing. The height of the cantilever arm 1 is limited by the top region 6 and the bottom region 7. The horizontal extension of the cantilever arm 1 is limited by the fixed region 2 and the cantilever region 8.

[0015] The upper end region 6 together with the recess 5 forms a force application device 9, through which the load 4 is applied to the cantilever arm 1. The recess 5 is used in a known manner, for example to place a shelf, which is omitted for simplicity of the illustration, on the cantilever arm 1. The force application device 9 is therefore at least partially located in the cantilever region 8 and introduces at least a part of the operating load 4 into the cantilever region 8 during operation.

[0016] The modified opening 10 passes through the flat body 11 of the cantilever arm 1 and is arranged in the flat body 11 so as to be completely surrounded by the flat body 11. The modified opening 10 has a horizontal extension h, which is limited on one side by the fixed side region 2 and on the other side by the cantilever side region 8. Furthermore, the modified opening 10 has a vertical extension v, which is limited by the upper end region 6 and the lower end region 7. Finally, all edge regions of the modified opening 10 lie in the plane of the flat body 11, i.e. they are not formed in any way out of this plane.

[0017] In the illustrated embodiment, when load 4 acts on cantilever arm 1 across its entire horizontal extent (in the illustrated embodiment, force application device 9 spans the entire horizontal extent of the cantilever arm), at least a portion of load 4 is introduced into cantilever region 8. Because cantilever region 8 is cantilevered and not fixed, it moves downwards according to the restoring force characteristics of body 11, while fixed region 2 remains stationary. The deformation opening also deforms accordingly, with edge region 12 facing the fixed region being substantially unaffected by the displacement, while edge region 13 facing the cantilever region follows the displacement. Thus, opposing edge regions 12, 13 are displaced relative to each other according to the value of load 4 currently acting on them.

[0018] During operation, i.e. when an operating load 4 acts on the cantilever arm 1, no relative displacement occurs between the part of the force application device 9 arranged in the cantilever region 8 and the cantilever region 8, since the openings 5 ​​and 5' are fixedly arranged there. The operating load 4 acts on the deformation opening 10 via the cantilever region 8, causing the above-mentioned relative displacement of the edge regions 12, 13 of the deformation opening 10.

[0019] The cantilever arm 1 further comprises a connection device, formed in the illustrated embodiment by holes 14, 15, at which a suitable deformation sensor 16 (see, for example, FIG. 4), omitted for the sake of simplicity, can be fixed to the body 11. The relative displacement of the edge regions 12, 13 results in a relative displacement of the holes 14, 15, which displacement is detected by the deformation sensor 16. The deformation sensor 16 then generates a deformation or load signal, which can be output as a weight by suitable evaluation electronics generally known to those skilled in the art and can be used, for example, for warehouse accounting. The evaluation electronics, including associated cables etc., have been omitted to reduce the complexity of the illustration.

[0020] It should be noted that those skilled in the art can adjust the dimensions of the deformation opening by using simulation calculations or by testing so that the relative displacement of the edge regions 12, 13 under the intended range of assumed loads 4 falls appropriately within the operating range of the deformation sensor 16. Therefore, the connection device is preferably designed to operatively fasten the deformation sensor between the fixed region and the cantilever region. As will be explained below, the deformation sensor 16 is preferably designed as a vibrating wire sensor, but it can also be composed of an expandable body equipped with a strain gauge. Finally, the cantilever arm 1 is further provided with openings 17, as shown in the figure; these openings are used for fastening a cover, fastening a cable, etc., and are unrelated to the function of the cantilever arm 1 or the deformation opening 10 to measure the operating load 4.

[0021] The cantilever arm shown in Figure 1 has a very simple design, can be manufactured in a single stamping process, and can be used without any additional manufacturing steps other than the installation of the deformation sensor. Compared to conventional cantilever arms incorporating load cells or weight sensors, it is very cost-effective. At the same time, despite its thin body 11, it can withstand high loads due to its vertical operating state (which results in a very high moment of inertia in the load direction).

[0022] It should be noted that the force application device does not necessarily have to be designed to accommodate a shelf placed on the cantilever arm 1. For example, an opening 5' for suspending the operating load 4' could be provided instead of the recess 5. In this case, a person skilled in the art would be able to appropriately design the force application device so that the use of the cantilever arm according to the present invention is not limited to shelves on a conventional frame.

[0023] A cantilever arm capable of being fixed at one side to an object is obtained, the cantilever arm comprising a resilient material, designed to receive a variable load, having a flat body arranged in a vertically adjusted manner on a surface in operation, the cantilever arm having, in the operating position, a height defined by upper and lower end regions and a horizontal extension defined on one side by a fixed side region for fixing the cantilever arm to an object and on the other side by the opposite cantilever side region, the cantilever arm further comprising a force applying device designed to support the load, the flat body of the cantilever arm further forming a deformation opening and a connection device for a deformation sensor for measuring the deformation of the cantilever arm under a current load, the deformation opening being defined by the flat body and passing through the flat body and the flat body. the deformation opening is completely surrounded by a flat body, all edge areas of the deformation opening lie in the plane of the flat body, the deformation opening has a horizontal extension limited by a fixed side area and a cantilever side area and a vertical extension limited by an upper end area and a lower end area, and deforms accordingly in a predetermined manner under each current load; furthermore, the force application device is formed by the body of the cantilever arm and is designed such that, in the operating position of the cantilever arm, at least a part of the load is introduced into the force application device without causing a relative displacement between the force application device and the cantilever side area; the connection device is designed to clamp the deformation sensor between the fixed side area and the cantilever side area and to make the sensor operational.

[0024] 2 shows a section of a cantilever arm 20, which is designed essentially similarly to the cantilever arm 1 (FIG. 1), but in which the deformation opening 10 is provided with a modified connection device for connecting to a deformation sensor. The modified connection device here also comprises an arm 21 which protrudes from the edge region 12 into the deformation opening 10 and which, like the hole 15, is also provided with a hole 22 for fastening the deformation sensor. Since the arm allows the holes 15, 22 to be arranged essentially one above the other, the deformation sensor fastened via these holes 15, 22 is no longer inclined to the vertical (as in the embodiment of FIG. 1) but is instead aligned vertically, and the relative displacement of the holes 15, 22 is less susceptible to deformations or distortions of the deformation opening 10, which are caused not by the load 4 but by the shape of the body 11 of the cantilever arm 20. This eliminates even small measurement errors and improves the measurement accuracy achievable with the cantilever arm according to the invention.

[0025] Likewise, the arms can be provided so as to extend from the edge 13 of the deformation opening 10 into the deformation opening 10. The result is a cantilever arm with at least one arm whose connection device preferably projects from one of the side regions into the deformation opening and has connection means for a deformation sensor in its tip region.

[0026] 3 shows a further modified section of the cantilever arm 25 with a connection device for connection to the deformation sensor. Two arms 26 and 27 with holes 28 and 29 for fastening the deformation sensor are visible. The arms 26 and 27 protrude inward from one of the sides 12, 13 of the deformation opening 10, respectively, with the advantage that the holes are arranged one above the other (vertically), providing an ideal space for the deformation sensor within the deformation opening 10.

[0027] This preferably results in a cantilever arm in which the connection device has two arms, one arm protruding from the fixed side region and the other arm protruding from the cantilever side region into the deformation opening 10, each arm having a tip region with connection means (holes 28, 29) for the deformation sensor.

[0028] More preferably, the two arms are designed in such a way that the connection means for the deformation sensors (holes 28, 29) are arranged substantially vertically one above the other at a distance in the operating position of the cantilever arm 25. Thus, compared to an obliquely arranged deformation sensor (see also above), the distance between the holes 28, 29 is less affected by distortions of the deformation opening 10 that are not in the load direction of the operating load 4.

[0029] More preferably, the tip region of the arm from the fixed side region is closer to the upper side region, and the tip region of the arm from the cantilever side region is closer to the lower side region of the cantilever arm. Therefore, the distance between the holes 28, 29 is optimal, although it is slightly affected by distortion of the deformation opening 10 that is not in the load direction of the operating load 4. For such distortion, see, for example, the description of Figure 7 or Figure 8.

[0030] 4 shows a portion of the cantilever arm 25, for example as shown in FIG. 3, with a diagrammatically shown deformation sensor, designed as a vibrating wire sensor 35, operatively fastened to the connecting device. Vibrating wire sensors of the type diagrammatically shown are known to those skilled in the art and are available, for example, from Digi Sens AG under the designation KL66. Preferably, the cantilever arm according to the invention further comprises a deformation sensor operatively fastened to the connecting device.

[0031] The vibrating wire sensor 35 comprises an elastically deformable body (here, designed as a frame 36), which is connected at both ends to the holes 28 and 29 and is subjected to tension when the load 4 is applied. As a result, the body deforms, and the tension of the deformation measuring element (designed as a vibrating string 37) increases (or decreases) compared to the rest state. This changes the resonant frequency, allowing the deformation of the body (here, frame 36) to be detected, as well as the relative displacement of the holes 28 and 29. The deformation signal of the vibrating wire sensor 35 can be converted by the evaluation electronics into a signal representing the magnitude of the currently acting operating load 4 in a manner known to those skilled in the art. Preferably, the deformation sensor comprises an elastically deformable body fastened to a connecting device so as to be elastically deformed by the deformation of the deformation opening, and a deformation measuring element for detecting the deformation of the body is arranged on the body. More preferably, the deformation measuring element is designed as a vibrating wire, and the deformation sensor is designed as a vibrating wire sensor.

[0032] FIG. 5 shows a further embodiment of a cantilever arm 40 according to the invention, whose force applicator 9′ is designed so that, in the operating position of the cantilever arm 40, substantially the entire operating load is introduced into the cantilever region 8. For this purpose, the upper end region 6 is provided with a recess 5 only in the area of ​​the cantilever region 8 (see the description of FIG. 1), so that the weight of, for example, a shelf rests exclusively on the cantilever region 8. In this case, such a shelf can be designed to be elongated and shortened in the x-direction, so that it only covers the cantilever region 8, or it can extend up to the hook 3 but is not supported by the cantilever arm 40 outside the cantilever region 8. In general, the force applicator is preferably provided in the upper end region 6 and extends at least over the cantilever region. Even in this arrangement, the fixed arrangement of the openings 5 ​​and 5′ prevents any relative displacement between the force applicator 9 and the cantilever region 8, even under operating loads. The operating load 4 therefore acts on the deformation opening 10 via the cantilever region 8.

[0033] FIG. 6 shows a further embodiment of a cantilever arm 45 according to the invention, which, like the embodiment of FIG. 5, is designed so that in the operating position of the cantilever arm 40, substantially the entire operating load is applied to the cantilever side 8. In contrast to the arrangement of FIG. 5, however, the force application device 9 extends over the entire upper end region 6, as in the embodiment shown in FIG. 1. However, the cantilever arm 45 also has a preferably slot-shaped relief opening 46, which starts from the fixed side region 2, extends towards the cantilever side region 8, extends above the deformation opening 10, is located below the force application device 9 and preferably extends over the entire horizontal extent h of the deformation opening 10. The operating load 4 is therefore introduced by the force application device 9 only into the cantilever side region 8 (and only from there into the deformation opening 10). This prevents undesired distortion of the deformation opening 10; only the edge 13 facing the cantilever side region 8 is displaced downwards in an approximately translational manner, without tilting obliquely. For example, arm 27 (when using the embodiment of Figure 3) also displaces substantially translationally, i.e., arm 27 does not substantially assume other angular positions where the distance between holes 28, 29 (Figure 3) changes due to deformations of body 11 that do not represent the value of load 4. Note that, as before, during operation, load 4 is introduced into cantilevered portion (8) without causing any relative displacement between the cantilevered region and the portion of force applicator (9) located on cantilevered portion (8).

[0034] In other words, the relief opening 46 makes it possible to maintain the measurement accuracy even if the force application device 9 extends above or beyond the deformation opening 10 into the fixed region 2 (naturally, as shown in FIG. 6 , there are no hooks 3 present on the force application device 9). Preferably, the force application device 9 extends from the cantilever region 8 further above the deformation opening 10, particularly preferably beyond this and onto the fixed region 2. Even more preferably, starting from the fixed region 2, a relief opening 46, particularly preferably slot-shaped, is provided, which extends towards the cantilever region 8 and is located above the deformation opening 10, particularly preferably over its entire horizontal extent h.

[0035] 7 shows a further embodiment of a cantilever arm 50 according to the invention, which is provided with a preferably slot-shaped distortion correction opening 51. The distortion correction opening extends continuously around part of the circumference of the deformation opening 10, i.e., the height portion 52 extends over at least part of the height v of the deformation opening, and the horizontal portion 53 extends over at least part of the horizontal extent h of the deformation opening, thus forming an L-shaped structure. In the embodiment shown, portions 52, 53 extend over the entire horizontal x-extent and vertical y-extent of the deformation opening 10.

[0036] As previously discussed in the description of FIG. 1, when an actuation load 4 acts on a cantilever arm designed according to any of the figures, the cantilever arm is less likely to deform in the direction of actuation load 4, but only to the extent that the associated deformation of deformation opening 10 can be detected by a deformation sensor. In the horizontal, z-direction, the cantilever arm is thin, flat, and therefore flexible, so that under the actuation load 4, the body 11 of the cantilever arm will undesirably twist or deform, for example, about axis 54 (shown in dashed lines). Region 80 of body 11 located below axis 54, which includes at least a portion of fixed region 12, will largely remain in the desired vertical position, while region 81 located above axis 54, which includes the force applicator, will twist, bend, or kink somewhat in the z-direction and will remain in this position when actuation load 4 is stationary.

[0037] This twisting causes an unintended change in the distance between the holes 28, 29, but this change does not reflect the operating load 4 and depends on the flexibility of the body 11 in the bending of the z-direction. This undesired change in distance is detected by the deformation sensor and leads to an inaccurate measurement of the operating load 4, which may not be acceptable depending on the required measurement accuracy.

[0038] The distortion correction opening 51 prevents twisting in the z-direction of the edges of the deformation opening 10, particularly the edge region 13 and the upper edge region 55, because these regions are no longer pulled by the region 81 of the body 11 located above the axis 54, but are separated from them by the distortion correction opening 51. In other words, the distortion correction opening 51 improves measurement accuracy and prevents erroneous measurements due to the bending flexibility of the body 11.

[0039] FIG. 8 shows a further embodiment of a cantilever arm 60 according to the present invention, comprising the strain correction opening 51 shown in FIG. 7 and a second strain correction opening 61 designed similarly to the strain correction opening 51. The second strain correction opening 61 is also preferably slit-shaped and has an L-shaped structure. In the illustrated embodiment, portions 62, 63 of the second strain correction opening extend across the entire horizontal x-range or vertical y-range of the deformation opening 10, with the height portion 62 aligned along the fixed side edge 12 of the deformation opening 10 and the horizontal portion 63 aligned along the lower edge 64 of the deformation opening 10. This second strain correction opening 61 further reduces the effects of twisting and bending around the axis 54, further improving measurement accuracy. This is because the deformation opening 10 is substantially insensitive to twisting in the z-direction, but is still subject to deformation due to the operating load 4, which is detected by the deformation sensor as described above.

[0040] This preferably results in a cantilever arm with two distortion correction openings 51, 61 arranged so that together they extend completely around the deformation opening 10, but with adjacent ends of the two distortion correction openings spaced apart from each other by intermediate regions 65, 66 within the body of the cantilever arm.

[0041] Furthermore, a cantilever arm 50 is preferably obtained in which the transition region 65 provided on the fixed side region 2 side is simultaneously located on the upper end region 6 side, and the transition region 66 provided on the cantilever side region 8 side is simultaneously located on the lower end region 7 side. This configuration is particularly advantageous with respect to torsion in the z direction, and measurement errors caused by torsion in the z direction are substantially eliminated.

[0042] In summary, it can be seen that at least one distortion correction opening 51, 61 is provided, which extends continuously around the periphery of the deformation opening 10 at least partially over a height v on the side of the fixing region 2 or the side of the cantilever region 8 and at least partially over a horizontal range h on the side of the upper end region 6 or the side of the lower end region 7, and is preferably slit-shaped, and particularly preferably extends over the entire height v and horizontal range h of the deformation opening 10. Preferably, at least one of the distortion correction openings 51, 61 is located completely within the body 11, and particularly preferably both are located within the body 11.

[0043] It should be noted that, depending on the design of the cantilever arm according to the present invention, the position of axis 54 may change or twisting of body 11 may occur, as is common practice, such that body 11 is distorted in the z-direction out of the plane of the body. The distortion correction openings 51, 61 also achieve the desired effect, i.e., that unwanted twisting of body 11 does not cause measurement errors when measuring the value of operating load 4.

[0044] FIG. 9 shows a simulation calculation of deformation of the cantilever arm 50 of FIG. 8, in which the effect of the distortion correction openings 51, 61 is achieved by having the opposing edges of each distortion correction opening 51, 61 at different positions.

[0045] FIG. 10 shows a further embodiment of a cantilever arm 70 according to the invention, which has at least one, here two, reinforcing elements designed as reinforcing ribs 71 and 72 arranged on the body 11 to reduce twisting in the z-direction (according to the above explanation of FIGS. 7 to 9). Preferably, the strip-shaped reinforcing ribs 71 and 72 project from the body 11 in the z-direction, i.e. horizontally and at right angles (see also FIG. 11). This increases the moment of inertia of the body 11 of the cantilever arm 70 about an axis lying in its plane, for example about axis 54. Preferably, to prevent twisting of the body 11 of the cantilever arm 70, at least one reinforcing element (here reinforcing ribs 71 and 72) is provided, which extends from the fixed region 2 towards the cantilever region 8 and along at least one of the upper end region 6 and the lower end region 7 over the horizontal extent h of the deformation opening 10. This reduces twisting in the z direction under the operating load 4, further improving measurement accuracy.

[0046] FIG. 11 shows cantilever arm 70 with reinforcing ribs 71, 72, viewed from the direction opposite the x-direction according to arrow 73 shown in FIG. 10, with arrow 74 indicating the viewing direction into the cantilever arm in FIG. 10. Additionally, FIG. 11 shows vibrating wire sensor 35 according to FIG. 4, which is attached to arms 26, 27 and is not shown on cantilever arm 70 in FIG. 10. The vibrating wire sensor is attached to arms 26, 27 via a threaded connection, symbolized by lines 75, 76 (arms 26, 27 are omitted to reduce the complexity of the illustration). When operating load 4 is applied, twisting or bending of body 11 occurs along double arrow 77, and the reinforcing elements or ribs 71, 72 cause a slight shift in the z-direction of the associated neutral axis 78 of body 11. Because the sensor 35 is also positioned slightly adjacent to the body 11 in the z-direction, the displaced neutral axis 78 is closer to the sensor 35 than it would be without the reinforcing ribs 71, 72 (in which case the neutral axis would be within the body 11 and further away from the sensor 35). This is advantageous because measurement errors caused by bending or twisting along the double arrow 77 arise primarily because the corresponding neutral axis does not pass through the sensor 35, thereby falsifying the relative displacement of the holes 28, 29 and thus the measurement result. The reinforcing elements (here the reinforcing ribs 71, 72) have the dual effect of suppressing harmful distortions in the z-direction and thus reducing the measurement error, and, in the event of residual twist remaining, the neutral axis 78 of the body 11 is slightly displaced in the z-direction, reducing the corresponding residual measurement error. This results in high measurement accuracy.

[0047] Figure 12 shows a preferred embodiment cantilever arm 80 for most accurately measuring the operating load 4. Shown is a connection arrangement having the relief opening 46 of Figure 6, the two distortion correction openings 51, 61 of Figure 8, and the arms 26, 27 of Figure 7. Again, deformation sensors such as the vibrating wire sensor 35 have been omitted for clarity.

[0048] It should be noted that the features described above individually in the figures can be combined or omitted as desired by those skilled in the art in specific cases, since synergies between the features, which are obtained for example from the embodiment of figure 12, can also in principle be used individually or in different combinations.

[0049] As mentioned above, the cantilever arms according to the invention are further preferably used in adjacent pairs in a frame to jointly support shelves on which items can be stored and handled. Preferably, each cantilever arm is provided with a deformation sensor connected to an evaluation unit. This preferably results in a frame comprising at least one pair of identically designed and associated cantilever arms having any combination of the above features, each pair of cantilever arms jointly supporting shelves designed to accept variable operating loads.

Claims

1. A cantilever arm (1, 20, 25, 40, 50, 60, 70) capable of being fixed at one side to an object, said cantilever arm comprising a resilient material, designed to receive a variable load (4), and having a flat body (11) arranged with a surface adjusted vertically in operation, said body being defined in its operating position by a height (v) defined by an upper end region (6) and a lower end region (7), and by a fixed side region (2) for fixing said cantilever arm (1, 20, 25, 40, 50, 60, 70) to an object on one side, and by a cantilever side region (8) on the other side. The cantilever arm (1, 20, 25, 40, 50, 60, 70) has a horizontal extension (h) that is limited in one direction and the other direction, and the cantilever arm (1, 20, 25, 40, 50, 60, 70) further comprises a force application device designed to support a load (4), and the flat body (11) of the cantilever arm (1, 20, 25, 40, 50, 60, 70) is characterized in that it forms a deformation opening (10) and a connection device for a deformation sensor for measuring the deformation of the cantilever arm under a current load (4), the deformation opening (10) being formed by the flat body (11) and the flat body and is completely surrounded by said flat body (11), all edge areas of said deformation opening being in the plane of said flat body (11), said deformation opening having a horizontal extension (h) defined by said fixed side area (2) and said cantilever side area (8) and a vertical extension (v) defined by said upper end area and said lower end area, and under a respective current load (4), it deforms in a predetermined manner according to the current load, said force applying device further applying a force to the body (11) of said cantilever arm (1, 20, 25, 40, 50, 60, 70). and the connecting device is designed to clamp a deformation sensor between the fixed region (2) and the cantilever region (8) so that the deformation sensor is operable.

2. 2. A cantilever arm according to claim 1, wherein the connection device comprises at least one arm (21, 26, 27) projecting from a side region into the deformation opening (10) and having connection means for the deformation sensor in a tip region.

3. 2. A cantilever arm according to claim 1, wherein the connection device has two arms (26, 27), one arm protruding from the fixed side region (2) and one arm protruding from the cantilever side region (8) into the deformation opening (10), each arm (26, 27) having a tip region with connection means for the deformation sensor.

4. 4. A cantilever arm according to claim 3, wherein the two arms (26, 27) are designed such that, in the operating position of the cantilever arm, the connection means for the deformation sensors are arranged substantially vertically one above the other at a distance.

5. 5. A cantilever arm according to claim 3 or 4, wherein the tip region of the arm (28) from the fixed side region (2) is closer to the upper side region and the tip region of the arm from the cantilever side region (8) is closer to the lower end region (6) of the cantilever arm.

6. The cantilever arm of claim 1 further comprising a deformation sensor (35) operably fastened to the connection device.

7. 7. The cantilever arm of claim 6, wherein the deformation sensor (35) has an elastically deformable body (36) fastened to the connecting device so as to be elastically deformed by deformation of the deformation opening (10), and a deformation measuring element is arranged in the elastic body (36) to detect deformation of the elastic body (11).

8. 8. A cantilever arm according to claim 7, wherein the deformation measuring element is designed as a vibrating wire (37) and the deformation sensor is designed as a vibrating wire sensor (35).

9. 2. A cantilever arm according to claim 1, wherein the force application device is designed such that in the operating position of the cantilever arm, substantially the entire operating load (4) is introduced into the cantilevered region (8).

10. 2. A cantilever arm according to claim 1, wherein the force application device is provided in the upper end region (6) and extends over at least the cantilevered region (8).

11. 11. A cantilever arm according to claim 10, wherein the force application device extends from the cantilever region (8) further beyond the deformation opening (10), preferably beyond the deformation opening beyond the fixed region (2).

12. 2. A cantilever arm according to claim 1, characterized in that it is provided with a preferably slot-shaped relief opening (46) which starts from the fixed side region (2) and extends towards the cantilever side region (8) and extends above the deformation opening (10), preferably over the entire horizontal extent (h) of the deformation opening.

13. 2. A cantilever arm according to claim 1, wherein at least one distortion correction opening (51, 61) is provided, which extends continuously around the deformation opening (10)(10) with an L-shaped profile, preferably in the form of a slot, particularly preferably extending over the entire height (v) and horizontal extension (h) of the deformation opening (10)(10), at least partially over the height (v) on the side of the fixed side region (2) or the cantilever side region (8) and at least partially over the horizontal extension (h) on the side of the upper end region (6) or the lower end region (7).

14. 14. A cantilever arm according to claim 13, wherein two distortion correction openings (51, 61) are arranged so that they both extend completely around the deformation opening (10), but the adjacent ends of each of the two distortion correction openings (51, 61) are spaced apart from each other by an intermediate region (65, 66) in the body (11) of the cantilever arm.

15. 15. A cantilever arm according to claim 14, wherein the intermediate region (65) provided on the side of the fixed region (2) is also located on the side of the upper end region (6), and the transition region (66) provided on the side of the cantilever region is also located on the side of the lower end region (7).

16. 2. A cantilever arm according to claim 1, wherein at least one reinforcing element, a reinforcing rib (71, 72), is provided against torsion of the body (11) of the cantilever arm and extends from the fixed side region (2) to the cantilever side region (8) and along at least one of the upper end region (6) or the lower end region (7) over the horizontal extension (h) of the deformation opening (10).

17. 2. Cantilever arm according to claim 1, wherein the reinforcing elements are designed as reinforcing ribs (71, 72).

18. 16. A frame characterized by at least one pair of identically designed and inter-associated cantilever arms (1, 20, 25, 40, 50, 60, 70) according to any one of claims 1 to 15, each pair jointly supporting a shelf designed to accept a variable operating load (4).

19. 17. Frame according to claim 16, wherein the cantilever arms (1, 20, 25, 40, 50, 60, 70) are provided with deformation sensors connected to an evaluation unit.

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