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EP-4735843-A1 - WEIGHING SYSTEM AND COUPLING STRIP

EP4735843A1EP 4735843 A1EP4735843 A1EP 4735843A1EP-4735843-A1

Abstract

The invention relates to a weighing system (10), comprising a base (14), a load sensor (18) coupled in a vertically movable manner to the base (14) by means of a parallel link assembly, and a lever (24) hinged in a pivotable manner to the base (14) by means of a lever joint (22) and having a first lever arm (241) arranged on one side of the lever joint (22) and a second lever arm (242) arranged on the other side of the lever joint (22) and configured to receive a sensor arrangement, wherein the first lever arm (241) is coupled in a vertical-force-transmitting manner to the load sensor (18) by means of a coupling strip (30) which is fixed both to the first lever arm and to the load sensor (18). The invention is characterised in that the coupling strip (30) has two functional regions, which are characterised with respect to directly adjacent regions by a smaller width and smaller thickness, specifically – a thin-point joint (32), which has, in the longitudinal direction of the coupling strip (30), a thickness which initially reduces and after reaching a thickness minimum point increases again in order to define a localised first pivot axis (321) which extends parallel to the width direction and perpendicular to the longitudinal direction of the coupling strip (30), and – a resilience region (34, 34'), which has, in the longitudinal direction of the coupling strip (30), a thickness which initially reduces, after reaching a thickness minimum remains the same over a section which at least corresponds to its width and then increases again in order to define a continuous group of second pivot axes (341) parallel to the first pivot axis (321).

Inventors

  • GEISLER, MATTHIAS
  • Müller, Michael
  • BAJOHR, ULRICH

Assignees

  • Sartorius Lab Instruments GmbH & Co. KG

Dates

Publication Date
20260506
Application Date
20240618

Claims (19)

  1. 1. Weighing system (10) comprising a base (14), a load receiver (18) coupled to the base (14) in a vertically movable manner by means of a parallel link arrangement and a lever (24) pivotally articulated to the base (14) by means of a lever joint (22) with a first lever arm (241) arranged on one side of the lever joint (22) and a second lever arm (242) arranged on the other side of the lever joint (22) and designed to receive a sensor arrangement, wherein the first lever arm (241) is coupled to the load receiver (18) in a vertical force-transmitting manner by means of a coupling band (30) fixed both to it and to the load receiver (18), characterized in that the coupling band (30) has two functional areas which are characterized by a reduced width and reduced thickness compared to immediately adjacent areas, namely - a thin joint (32) which has a thickness which initially decreases in the length direction of the coupling band (30) and then increases again after reaching a point-like thickness minimum in order to define a localized, first pivot axis (321) which extends parallel to the width direction and perpendicular to the length direction of the coupling band (30), and - a resilience region (34, 34') which has a thickness which initially decreases in the length direction of the coupling band (30), remains constant after reaching a thickness minimum over a distance at least corresponding to its width and then increases again in order to define a continuous family of second pivot axes (341) parallel to the first pivot axis (321).
  2. 2. Weighing system (10) according to claim 1, characterized in that the thin-point joint (32) has a biconcave or bifacial V-shaped thickness profile in the longitudinal direction.
  3. 3. Weighing system (10) according to one of the preceding claims, characterized in that the thin-point joint (32) has a width which initially decreases in the longitudinal direction and then increases again after reaching a point-specific width minimum which is colocalized with the associated Dieken minimum.
  4. 4. Weighing system (10) according to claim 3, characterized in that the thin-point joint (32) has a biconcave or bilaterally V-shaped width profile in the longitudinal direction.
  5. 5. Weighing system (10) according to one of the preceding claims, characterized in that the thin-point joint (32) has a length between 2 mm and 20 mm, in particular between 4 mm and 6 mm.
  6. 6. Weighing system (10) according to one of the preceding claims, characterized in that the thin-point joint (32) has a thickness between 10 pm and 100 pm, in particular between 40 pm and 60 pm, at its minimum thickness.
  7. 7. Weighing system (10) according to one of the preceding claims, characterized in that the end regions of the resilience region (34, 34') have a bifacially rounded or oblique thickness profile in the length direction.
  8. 8. Weighing system (10) according to one of the preceding claims, characterized in that the resilience region (34, 34') has a width which initially decreases in the longitudinal direction and then increases again after reaching a width minimum which extends colocalized with the associated Dieken minimum.
  9. 9. Weighing system (10) according to one of the preceding claims, characterized in that the resilience region (34, 34') has a length between 5 mm and 50 mm, in particular between 6 mm and 10 mm.
  10. 10. Weighing system (10) according to one of the preceding claims, characterized in that the resilience region (34, 34') has a thickness between 50 pm and 150 pm, in particular between 80 pm and 120 pm, in the region of its thickness minimum.
  11. 11. Weighing system (10) according to one of the preceding claims, characterized in that the coupling band has a plurality of resilience regions (34').
  12. 12. Weighing system (10) according to claim 11, characterized in that the plurality of resilience regions (34') are arranged parallel to one another.
  13. 13. Weighing system (10) according to one of the preceding claims, characterized in that a lateral pivot region (39) is arranged in the length direction between the thin-point joint (32) and the resilience region (34, 34'), which consists of one or more parallel webs (392) extending in the length direction of the coupling band (30), each having a web width that is less than the thickness of the coupling band (30) in this region.
  14. 14. Weighing system (10) according to one of the preceding claims, characterized in that the length of the coupling band (30) is between 20 mm and 150 mm, in particular between 80 mm and 100 mm.
  15. 15. Weighing system (10) according to one of the preceding claims, characterized in that the width of the coupling band (30) outside the functional areas (32; 34, 34') and - if present - the lateral pivoting area (39) is between 5 mm and 10 mm.
  16. 16. Coupling band (30), consisting of a sheet metal strip, for vertical force-transmitting coupling between a load receiver (18) of a weighing system (10) and a first lever arm (241) of a lever (24) of the weighing system (10), characterized in that two functional areas are formed spaced apart from one another in the length direction of the sheet metal strip, which are characterized by reduced width and reduced thickness compared to immediately adjacent areas, namely - a thin joint (32) which has a thickness which initially decreases in the length direction of the coupling band (30) and then increases again after reaching a point-like thickness minimum in order to define a localized, first pivot axis (321) which extends parallel to the width direction and perpendicular to the length direction of the coupling band (30), and - a resilience region (34, 34') which has a thickness which initially decreases in the length direction of the coupling band (30), remains constant after reaching a thickness minimum over a distance at least corresponding to its width and then increases again in order to define a continuous family of second pivot axes (341) parallel to the first pivot axis (321).
  17. 17. Coupling band (30) according to claim 16, characterized in that it has several resilience regions (34').
  18. 18. Coupling band (30) according to claim 17, characterized in that the plurality of resilience regions (34') are arranged parallel to one another.
  19. 19. Coupling band (30) according to one of claims 16 to 18, obtained by - Providing a coupling band blank made of a spring-elastic metal sheet, - Laser processing of the coupling band blank to create length ranges of different thickness and/or width.

Description

weighing system and coupling belt Description field of the invention The invention relates to a weighing system comprising a base, a load receiver coupled to the base in a vertically movable manner by means of a parallel link arrangement, and a lever pivotally articulated to the base by means of a lever joint with a first lever arm arranged on the one hand of the lever joint and a second lever arm arranged on the other hand of the lever joint and designed to receive a sensor arrangement, wherein the first lever arm is coupled to the load receiver in a manner that transmits vertical forces by means of a coupling band fixed both to it and to the load receiver. The invention further relates to a coupling band, consisting of a sheet metal strip, for the vertical force-transmitting coupling between the load receiver of such a weighing system and the first lever arm of its lever. State of the art Generic weighing systems and coupling belts for them are known from DE 30 12 344 A1. The central component of an electronic scale, especially one that works according to the principle of electromagnetic compensation, is its weighing system. The term weighing system refers here to the mechanical lever mechanism by means of which a weighing carrier of the scale, which serves to hold the weighing goods to be weighed, is connected to the electronic sensor of the scale, typically a plunger coil arrangement with optical lever position detection. The weighing system comprises a base, by means of which it can be fixed to a platform or a housing of the scale. A so-called load receptor is articulated to said base via a parallel link arrangement, often referred to as a Roberval mechanism. The weighing goods carrier mentioned above is fixed directly or indirectly to the load receptor in the final assembled state of the scale. The parallel link arrangement serves to prevent the load receptor or the weighing goods carrier from tipping over, at least in the case of small deflections of the load receptor, which essentially occur on an arc with the radius of a parallel link length. A typical weighing system also comprises a lever which serves to transmit the path and force and which is articulated to the base via a lever joint. A first lever arm of said lever is coupled to the load receptor in order to transfer its movement caused by the weight of the weighing goods to the lever. A second lever arm of the lever is typically equipped with a receptacle for lever-side components of an electronic sensor, in particular a plunger coil, which interacts in a manner that is generally known and not relevant here with other base-side sensor components mounted on the base, in particular a magnet pot. Such a weighing system thus represents the "heart" of a scale, whereby similar weighing systems can be used in scales that are otherwise differently equipped. For the above-mentioned coupling between the first lever band and the load receiver, a connection, often generally referred to as a coupling, is required which is suitable on the one hand for transmitting vertical forces between the load receiver and the first lever arm and on the other hand is sufficiently flexible to achieve decoupling with regard to any non-vertical force components. As mentioned, a parallel link mechanism can prevent the load receiver from tipping, but cannot prevent its circular arc movement in addition to the vertical, also inherent horizontal movement components. However, these must not be transferred to the lever, as the corresponding non-vertical force components would distort the measured weight value, which is unacceptable, especially with extremely high-resolution precision scales. In order to combine both requirements, namely vertical coupling and non-vertical decoupling, said couplings can be in the form of thin metal strips can be designed as so-called coupling bands. If the coupling band is designed to be sufficiently thin, non-vertical decoupling can be achieved that is sufficient even for extremely high-resolution scales. However, it has been found that corresponding weighing systems are extremely susceptible to lateral acceleration forces, such as those that typically occur during transport, especially when shipping scales. Therefore, a great deal of effort must be put into packaging the scales to ensure that they arrive at the recipient with undamaged coupling bands. The theoretical approach of only fixing the coupling band to the load receptor and first lever arm after the scale has been set up at the destination is practically impossible to implement for legal calibration reasons. DE 32 42 954 A1 discloses a coupling designed as a coupling rod, which has a functional area tapered in thickness and width near its respective fixing areas on the load receiver and the first lever arm. Together, these functional areas are intended to generate the elasticity of the coupling required for non-vertical decoupling. Coupling rods of this type are more robust than coupl