weighing sensor screw

Abstract

Weighing transducer (1) with a force application area (2) and a land body (3), wherein the land body (3) is connected to the force application area (2) via at least one parallelogram link (4, 5) and the land body (3) is connected to a fixed area, wherein four attachment points (12, 13) are arranged on the land body (3) which span a mounting area (10), wherein two front attachment points (12) are located a smaller distance to the force application area (2) than two rear attachment points (13), wherein the four attachment points (12, 13) are screwed to a fixed area, characterized in that the attachment points (12, 13) form the corners of a trapezoid in a top view of the mounting area (10), wherein the trapezoid is designed such that the two parallel base sides have different lengths.

Description

AREA OF INVENTION

[0001] Weighing transducer with a force application area and a base body, wherein the base body is connected to the force application area via at least one parallelogram linkage and the base body is connected to a fixed area, wherein four mounting points are arranged on the base body, wherein two front mounting points are located closer to the force application area than two rear mounting points, and wherein the four mounting points are bolted to a fixed area. TECHNICAL BACKGROUND

[0002] Scales measure the force applied to the force application area of ​​the weighing transducer. Typically, such scales are equipped with weighing transducers that have a monolithic structure, where the essential components of the transducer, in particular at least the base, the load-bearing area, and the parallelogram linkage, are machined from a single block of material. These weighing transducers have a force application area, which is connected, for example, to a weighing pan, and a base, which is connected to a stationary area, in particular a scale housing. The force to be measured is applied to the force application area. Weighing transducers can consist of either an elastically deformable body or a lever mechanism that operates on the principle of electromagnetic force compensation.

[0003] Numerous methods for connecting a weighing sensor to a fixed area are known in the prior art. For example, it is known to fasten the weighing sensor with only one screw. It is also known to fasten a weighing sensor with two screws, the screws being located either in the longitudinal direction or perpendicular to an imaginary connecting line from the respective center of the screws.

[0004] DE 31 47 470 A1 describes a monolithic weighing transducer with three attachment points each, which connect the weighing transducer to a base plate and a load-bearing device, wherein the three attachment points each are arranged symmetrically and run along a longitudinal extension plane of the weighing transducer.

[0005] EP 1 574 829 A1 discloses a three-point screw connection in which the triangle with legs of equal length is symmetrical to the longitudinal plane.

[0006] DE 199 23 207 C1 discloses a weighing sensor with four mounting points, these being arranged in a rectangular pattern.

[0007] A disadvantage of the prior art, however, is that with a two-point mounting, the weighing sensor can tilt along the connecting axis of the mounting points. With a three-point mounting, the front mounting point can tilt because it is a point-like structure. With the known four-point mounting, thermal stress can occur. SUMMARY

[0008] It is therefore an object of the invention to provide a weighing sensor which eliminates or at least reduces the known disadvantages of the prior art.

[0009] This task is achieved in a weighing transducer of the type mentioned above by means that the mounting points are trapezoidal. The trapezoidal arrangement of the mounting points improves the support reactions in the area of ​​the mounting points and on the land body, particularly on the projecting area of ​​the land body, in such a way that it reduces the tilting in the front area of ​​the mounting points in the transverse direction to the weighing transducer.

[0010] In a further embodiment, at least one, preferably two, mounting points are arranged in a projecting area of ​​the land body. Support in the area of ​​the projecting area of ​​the land body has the advantage of preventing or reducing deflection of this area. This avoids or reduces measurement errors resulting from deflection of the load cell due to the force being measured. Preferably, one base side of the trapezoidally arranged mounting points is located in the area of ​​the projecting area of ​​the land body. In particular, the shorter base side of the trapezoidally arranged mounting points is located in the area of ​​the projecting area of ​​the land body.

[0011] In a further embodiment, at least one mounting point, preferably two mounting points, is arranged in the area of ​​the at least one parallelogram link. This places the mounting points further inwards in the longitudinal plane of the parallelogram link, thereby maintaining the torsional stiffness of the parallelogram link in the outer area.

[0012] In a further embodiment, at least one attachment point, preferably two attachment points, is arranged in the area of ​​the pivot points of the at least one parallelogram link. This only slightly reduces the torsional stiffness of the parallelogram link.

[0013] In a further embodiment, the length of the shorter base side of the trapezoidally arranged mounting points is at least twice the diameter of a mounting point, and the length of the shorter base side of the trapezoidally arranged mounting points is at most five times the diameter of a mounting point. This keeps the distance between the two mounting points as small as possible. This arrangement prevents or reduces stress on the weighing sensor and prevents it from tilting.

[0014] In a further embodiment, at least one thin section is arranged between the front mounting points and the rear mounting points, or between the front mounting points and the main body. This serves to additionally decouple the mounting points from the stationary, housing-side area. The thin section prevents thermal stresses. In particular, at least one pivot point of the parallelogram linkage can be arranged between the mounting points.

[0015] In a further embodiment, the trapezoidally arranged mounting points form an isosceles trapezoid. Due to the isosceles shape, the stresses occurring on the weighing sensor are distributed evenly or reduced.

[0016] In a further embodiment, at least one spacer is arranged at the mounting points, preferably being integrally connected to the mounting points. The spacer serves to ensure that the weighing sensor, in particular the at least one parallelogram link, maintains a sufficient distance from the stationary area so that, during weight measurement, the parallelogram link or the weighing sensor does not come into contact with the stationary area. Alternatively, the spacer can also be designed as a bolt that is connected to the mounting points. For this purpose, the mounting points can have an internal thread and the bolt a corresponding external thread. List of characters

[0017] Further advantageous aspects will become apparent from the following description of preferred embodiments with reference to the drawings, wherein: Fig. 1. A schematic representation of a weighing sensor Fig. Figure 2 is a first top view of a weighing sensor. Fig. 3a is a second top view of a weighing sensor Fig. 3b is a schematic representation of the weighing sensor according to Fig. 3a Fig. 4a is a third top view of a weighing sensor Fig. 4b is a schematic representation of a section of the weighing sensor according to Fig. 4a DETAILED DESCRIPTION OF THE EXECUTION EXAMPLES

[0018] Fig. Figure 1 shows a schematic representation of the weighing sensor. 1 according to one exemplary embodiment. The weighing sensor 1 includes a force application area 2 , a continental body 3 , an upper parallelogram linkage 4 as well as a lower parallelogram linkage 5 , wherein the upper parallelogram linkage 4and the lower parallelogram linkage 5 , front joint areas 6 and rear joint points 7 exhibit. The continental body 3 has a projecting area 8 on, which extends from the mainland body 3 in the direction of the force application area 2 extends and thus into the lever system 9 protrudes. On the projecting area 8 of the continental body 3 is at least one lever of the lever system 9 supported by a first support joint. Furthermore, the mainland body 3 four attachment points 12 , 13 arranged, which form a fastening area 10 stretch out.

[0019] Fig. Figure 2 shows the weighing sensor 1 according to Fig. 1 in a first view. The attachment points 12 , 13 are on the continental body 3arranged in a trapezoidal shape. Two of the attachment points 12 , 13 are in the area of ​​the rear joint 7 of the lower parallelogram linkage 5 arranged in the lower parallelogram linkage. 5 There is a recess for this. 15 arranged. The front mounting points 12 , which are located in the area of ​​the rear joints 7 are preferably arranged in the immediate vicinity of a center line M of the weighing sensor 1 arranged at the front mounting points. 12 arranged symmetrically to the center line M.

[0020] Fig. 3a shows another arrangement of the attachment points 12 , 13 on the continental body 3 , with the front mounting points 12 on the projecting area 8 of the continental body 3 are arranged. Preferably the front mounting points12 in the immediate vicinity of a center line M of the weighing sensor 1 arranged at the front mounting points. 12 arranged symmetrically to the center line M. Furthermore, the lower parallelogram link has a recess for this purpose. 14 on.

[0021] Fig. Figure 3b shows a schematic representation of the weighing sensor. 1 according to Fig. 3. The weighing sensor 1 is advantageous with the projecting area 8 of the continental body 3 over a thin spot 16 connected. The front mounting points 12 are at one end 18 of the projecting area 8 arranged in the direction of the force application area 2 shows. Preferably, the attachment points are 12 in the last third of the projecting area 8 arranged in the direction of the force application area 2shows. Furthermore, the end can 18 of the projecting area 8 or the last third of the projecting area 8 a narrower area 17 exhibiting the narrow area 17 in the Y direction it has a smaller extent than the rest of the projecting area 8 Furthermore, in the narrow area 17 at least one joint of at least one lever of the lever system 9 arranged.

[0022] Fig. 4a shows another arrangement of the attachment points 12 , 13 on the continental body 3 , with the front mounting points 12 in the area of ​​the lower parallelogram linkage 5 are arranged. In particular, the attachment points 12 in the area of ​​the lower parallelogram linkage 5 in the longitudinal plane or in the X-direction, it is positioned further inwards. Thus, the lower parallelogram link has5 a recess 14 as well as another recess 15 , which are located between the recess 14 and the rear joint 7 of the lower parallelogram linkage 5 is located. The recess 15 It has an elliptical or rectangular geometry. Preferably, the front mounting points are 12 in the immediate vicinity of a center line M of the weighing sensor 1 arranged at the front mounting points. 12 arranged symmetrically to the center line M.

[0023] Fig. Figure 4b shows a schematic representation of a section of the weighing sensor. 1 according to Fig. 4a. Here it can be seen that the front mounting points 12 lie lower than the rest of the projecting area 8 of the continental body 3This is achieved by preferably using a milling cutter to clean the area around the front mounting points. 12 It is milled off. This creates a flat surface. 19 around the front mounting points 12 created, which around the front mounting points 12 There are no differences in elevation. Therefore, there is no difference in elevation or step. 20 between the projecting area 8 and the flat surface 19 , which are located within the projecting area 8 The two front mounting points are present. 12 within the flat surface 19 arranged. Preferably the flat surface 19 an elliptical or rectangular geometry. Due to the flat surface 19 No stresses can occur during the mounting of the weighing sensor. 1 with a fixed area.

[0024] In the Fig. 1 to Fig. 4b is the length of the shorter base side of the trapezoidally arranged fixing points. 12 , 13 maximum five times the diameter of a mounting point 12 , 13 Furthermore, the trapezoidally arranged fastening points 12 , 13 form an isosceles trapezoid. In particular, the attachment points 12 , 13 arranged symmetrically to the center line M.

[0025] In the Fig. 3a to Fig. 4b is between the front mounting points 12 and the rear mounting points 13 a rear joint 7 of the parallelogram linkage ( 4 , 5 ) arranged. Reference symbol list 1 weighing sensor 2 Force application area 3 continental bodies 4 upper parallelogram linkage 5 lower parallelogram linkage 6 front pivot points parallelogram linkage 7 rear pivot points parallelogram linkage 8 projecting area of ​​the continental body 9 lever system 10 Mounting area 12 front mounting points 13 rear mounting points 14 Recess parallelogram linkage 15 Recess parallelogram linkage 16 thin spots 17 narrow area of ​​the projecting area 18 End of the projecting area 19 flat surface Level 20 M Center line QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 3147470 A1

[0004] EP 1574829 A1

[0005] DE 19923207 C1

[0006]

Claims

[1] Weighing transducer (1) with a force application area (2) and a land body (3), wherein the land body (3) is connected to the force application area (2) via at least one parallelogram link (4, 5) and the land body (3) is connected to a fixed area, wherein four attachment points (12, 13) are arranged on the land body (3), wherein two front attachment points (12) are located a shorter distance from the force application area (2) than two rear attachment points (13), wherein the four attachment points (12, 13) are bolted to a fixed area, characterized by , that the attachment points (12, 13) are trapezoidal in shape. [2] Weighing transducer (1) according to claim 1, characterized by , that the two front attachment points (12) are arranged in a projecting area (8) of the mainland body (3). [3] Weighing transducer (1) according to claim 2, characterized by, that one base of the trapezoidally arranged attachment points (12, 13) is located in the area of ​​the projecting area (8) of the mainland body (3). [4] Weighing sensor (1) according to claim 3, characterized by , that the shorter base of the trapezoidally arranged attachment points (12, 13) is located in the area of ​​the projecting area (8) of the mainland body (3). [5] Weighing sensor (1) according to any one of the preceding claims, characterized by , that a step (20) is arranged between the projecting area (8) and a flat surface (19), wherein the flat surface (19) is arranged within the projecting area (8). [6] Weighing sensor (1) according to claim 5, characterized by , that the two front attachment points (12) are arranged within the flat surface (19), [7] Weighing sensor (1) according to any one of the preceding claims, characterized by, that the two front mounting points (12) are arranged in the area of ​​the at least one parallelogram link (4, 5). [8] Weighing sensor (1) according to any one of the preceding claims, characterized by , that the two front mounting points (12) are arranged in the area of ​​the joint (7) of the at least one parallelogram link (4, 5). [9] Weighing sensor (1) according to any one of the preceding claims, characterized by , that the length of the shorter base of the trapezoidally arranged fixing points (12, 13) corresponds at most to five times the diameter of a fixing point (12, 13). [10] Weighing transducer (1) according to any one of the preceding claims, characterized by , that the joint point (7) of the parallelogram linkage (6, 7) is arranged between the attachment points (12, 13). [11] Weighing sensor (1) according to any one of the preceding claims, characterized by, that the trapezoidally arranged attachment points (12, 13) form an isosceles trapezoid. [12] Weighing sensor (1) according to any one of the preceding claims, characterized by , that the attachment points (12, 13) are arranged symmetrically to a center line (M). [13] Weighing sensor (1) according to any one of the preceding claims, characterized by , that at least one recess (14, 15) is arranged in at least one parallelogram link (4, 5).

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