Belt scale for weighing products

Abstract

Belt scale (100) for weighing products (130), the belt scale (100) comprising a weighing area (102) for weighing products (130), a circulating conveyor belt (101) for conveying products (130) into the weighing area (102), and a drive device (103) for driving the conveyor belt (101), wherein the conveyor belt (101) comprises two rows (250, 260) of engagement openings (251, 252, 261, 262, 263), wherein the engagement openings (251, 252, 261, 262, 263) are arranged alternately in the two rows (250, 260) when viewed in a transport direction (T) of products (130), wherein the drive device (103) comprises two drive pulleys (131, 132), each The drive disc (131, 132) comprises engagement elements (311, 321) and each drive disc (131, 132) is arranged to engage in exactly one of the two rows (250, 260) of engagement openings (251, 252, 261, 262, 263) for driving the conveyor belt (101),wherein an angle (Σ) formed between two immediately adjacent access openings (262, 261) in one of the first of the two rows (250, 260) and the access opening (251) nearest to these access openings (262, 261) of the other of the two rows (250, 260) is less than 10° or less than 5° or less than 2.5°.

Description

[0001] The present invention relates to a belt weighing scale for weighing products according to claim 1 and a method for weighing products using a belt weighing scale for weighing products according to claim 12. State of the art

[0002] Belt weighing systems are well known from the prior art.

[0003] DE 10 2021 100 928 A1 describes a known belt weighing system in which a conveyor belt is set in motion in the transport direction via a suitable drive element or motor and can transport a product into a weighing area in which the product can be weighed and its weight determined.

[0004] In order to make the movement of the conveyor belt by means of the drive device as reliable as possible, in particular without slippage, it is known to provide a drive roller and / or deflection roller with engagement elements that can engage in engagement openings of the conveyor belt in order to ensure a transmission of the resulting drive force.

[0005] However, each engagement of the engagement elements with the openings in the conveyor belt transmits an impulse and thus a shock to the conveyor belt. This can lead to vibrations in the conveyor belt at a specific frequency (which is essentially equal to the rotational speed of the respective engagement elements divided by the distance between them), negatively affecting the accuracy of weight determination using the belt weigher. Task

[0006] Based on the known state of the art, the technical problem to be solved is therefore to specify a belt weighing scale for weighing products in which the accuracy of the weight determination of the products is increased. Solution

[0007] This problem is solved according to the invention by the belt weighing scale according to claim 1 and the method for weighing products with a belt weighing scale according to claim 12. Advantageous embodiments of the invention are described in the dependent claims.

[0008] The belt weighing scale according to the invention for weighing products comprises a weighing area for weighing the product, a circulating conveyor belt for conveying products into the weighing area, and a drive device for driving the conveyor belt, wherein the conveyor belt comprises two rows of engagement openings, wherein the engagement openings are arranged alternately in the two rows when viewed in a transport direction of products, wherein the drive device comprises two drive discs, each drive disc comprising engagement elements, and each drive disc is arranged to engage in exactly one of the two rows of engagement openings for driving the conveyor belt.

[0009] The alternating arrangement of the access openings means that when the conveyor belt moves in the direction of transport and when viewed in the direction of transport of products, in each of the two rows an access opening follows a closed area of ​​the conveyor belt, and when viewed perpendicular to the direction of transport, a closed area of ​​the conveyor belt in one of the two rows lies at the same height as an access opening in the other of the two rows.

[0010] This ensures that at any given time, at most one engagement element is either entering or exiting an opening. While this results in more impacts on the conveyor belt due to the engagement or exiting of the engagement elements, these impacts are of lower intensity / amplitude (since only one engagement element enters or exits an opening at any given time). This reduces the amplitude of the resulting impacts, making it easier to filter out these disturbances and thus increasing the reliability of product weight determination.

[0011] In one embodiment, the two drive pulleys are rotatably mounted about a common drive axis. The drive pulleys can, in principle, be identical in design, allowing them to be arranged along one direction of rotation about the drive axis such that the engagement elements are arranged alternately or offset from each other in the direction of rotation. The belt weigher can thus be manufactured cost-effectively.

[0012] It can be arranged that each of the two drive pulleys is assigned to exactly one drive element of the belt conveyor scale and that the two drive pulleys can move synchronously with each other. This allows the torques acting on the conveyor belt to be reduced, while at the same time taking into account forces acting differently on different sides of the conveyor belt when controlling the drive elements.

[0013] The two drive pulleys can be rigidly connected mechanically. For example, they can be formed as a single piece or rigidly connected via detachable or non-detachable connecting elements. This design is structurally simple.

[0014] It is possible to arrange the two drive pulleys on a single drive roller, and for the drive roller to be rotated by a drive element of the grinding belt scale to drive the conveyor belt. This embodiment reduces the number of separate components, thus reducing the potential for failure.

[0015] The angle formed between two immediately adjacent engagement openings in one of the two rows and the nearest engagement opening in the other of the two rows can be less than 10°, less than 5°, or less than 2.5°. Since the engagement elements alternately engage on different sides of the conveyor belt, large distances between the engagement openings can negatively affect the conveyor belt's positioning during operation and its wear. Within the angular range provided in this embodiment, the impact on the conveyor belt is particularly minimal, while still allowing for sufficiently large engagement openings and engagement elements.

[0016] The access openings can be designed as recesses in the conveyor belt pointing towards the drive pulleys. Preferably, the recesses do not extend completely through the thickness of the conveyor belt perpendicular to the transport plane, so that the conveyor belt is essentially closed on the surface facing away from the drive pulleys, or at least has no access openings. This prevents persistent contamination of the conveyor belt and thus also avoids impairments to the product quality of the weighed products. It also improves the weighing result.

[0017] It can be provided that at least two pairs of adjacent engagement openings in one of the two rows have the same distance apart. Preferably, all pairs of adjacent engagement openings can also have the same distance apart. In this embodiment, a pair of adjacent engagement openings is understood to mean that the engagement openings are directly adjacent, i.e., there is no other engagement opening in the same row between them. This distributes the loads acting on the conveyor belt evenly and also simplifies the design of the drive pulleys.

[0018] It may be provided that an engagement opening of one of the two rows, viewed in the transport direction of the products, is located in a position between two adjacent engagement openings of the other of the two rows and offset transversely to the transport direction, wherein the distance of the engagement opening in one of the two rows to one of the two adjacent engagement openings of the other of the two rows in the transport direction is between 25% and 75% of the distance of the two adjacent engagement openings.

[0019] Preferably, the spacing can be exactly 50%, with the distance being measured from the respective centers of the access openings. This achieves the most uniform possible distribution of the access openings in the opposing rows, which equalizes the forces acting on the conveyor belt during transport.

[0020] In one embodiment, it is provided that the engagement openings and the engagement elements are shaped in such a way that the engagement elements can be inserted into the engagement openings and / or removed from the engagement openings in a substantially impact-free manner.

[0021] The fact that the removal of the engagement elements from the engagement openings can be carried out essentially without impact means that only a small impulse transfer from the engagement elements to the conveyor belt occurs in the area of ​​the engagement openings in a direction perpendicular to the transport plane. Such an impulse input could occur, for example, due to tilting or the release of tilting between the engagement openings and the engagement elements. Preferably, the impulse transfer in a direction perpendicular to the transport direction is less than or at most 25%, more preferably less than or at most 10%, and more preferably less than or at most 5% of the magnitude of the impulse that is transferred from an engagement element to the conveyor belt in the transport direction. This can be ensured, for example, by avoiding an angular or edged shape for the engagement elements and / or engagement openings.These are each designed as elements that essentially have a curved surface.

[0022] The engagement elements and / or the engagement openings can include a contact surface for contacting the engagement openings and / or the engagement elements, which consists of or comprises a flexible material. This minimizes the impulse transfer to the conveyor belt, particularly in directions perpendicular to the transport plane or transport direction, thus reducing any impairment of the weighing result.

[0023] According to the invention, a method for weighing products using a belt weigher is provided, the belt weigher comprising a weighing area in which a product is weighed, a circulating conveyor belt for conveying the product into the weighing area, and a drive device for driving the conveyor belt, wherein the conveyor belt comprises two rows of engagement openings, the engagement openings being arranged alternately in the two rows when viewed in a transport direction of products, wherein the drive device comprises two drive discs, each drive disc comprising engagement elements, and each drive disc being arranged to engage in exactly one of the two rows of engagement openings for driving the conveyor belt, the method comprising conveying at least one product into the weighing area by the conveyor belt and weighing the product in the weighing area.During the movement of the conveyor belt in the direction of product transport, an engagement element of one and then the other of the two drive pulleys alternately engages with one and then the other of the two rows of engagement openings. This method allows the weight of the product to be determined with greater accuracy.

[0024] All of the described embodiments can be combined with each other. Brief description of the characters Fig. Figure 1 shows a belt sander according to one embodiment. Fig. Figure 2 shows a conveyor belt of a grinding belt scale according to one embodiment in a top view. Fig. Figure 3 shows an embodiment of the drive discs. Fig. Figure 4 shows another embodiment of the drive discs. Fig. Figure 5 shows an embodiment of a conveyor belt together with a drive pulley. Detailed description

[0025] Fig. Figure 1 shows a belt scale 100 for conveying and weighing products 130 (especially foodstuffs such as dough, sausage, or cheese) according to one embodiment. The basic design of belt scales is well known to those skilled in the art. The belt scale 100 shown here includes, by way of example, a frame 110 to which several components of the belt scale can be mounted. For example, a power supply or control unit can be provided as component 111 (e.g., in the form of a mains connection or a computer with associated memory and a corresponding processor).

[0026] The belt weighing scale 100 further comprises a weighing area 102 in which, for example, a product 130, positioned in or placed in the weighing area 102, can be weighed using a load cell (not shown). To transport this product 130 into the weighing area 102, the belt weighing scale also includes a conveyor belt 101 on which the product 130 is arranged and transported along the transport direction T, for example, towards the weighing area 102 or subsequently, after the product's weight has been measured, away from it. Upstream and / or downstream of the belt weighing scale, further equipment, such as for processing the product 130, can be arranged. The conveyor belt 101 can be designed as an endless circulating conveyor belt.

[0027] According to the invention, the belt weigher 100 further comprises at least one drive unit 103, which can drive the conveyor belt 101 in the transport direction T. The drive unit 103, according to the invention, comprises at least two drive pulleys 131 and 132, which have engagement elements (not shown) that can engage in engagement openings (also not shown) of the conveyor belt 101 in order to exert a force on the conveyor belt in the transport direction T and thus drive the conveyor belt. The drive pulleys can be provided as physically separate components, which, for example, but not necessarily, are rotatably mounted on a common axis of rotation. Alternatively, the drive pulleys 131 and 132 can also be rigidly connected to each other, for example by screws and / or adhesive bonds.The mechanically rigid connection can be detachable or non-detachable, whereby a detachable mechanically rigid connection is to be understood as a connection that allows non-destructive separation of the drive discs 131 and 132 (e.g. screw connections or click connections or plug connections).

[0028] Fig. Figure 2 shows a more detailed view of the conveyor belt 101 according to one embodiment. In the view shown here, the conveyor belt is depicted as consisting of a continuous material and can, for example, be made of or comprise rubber or a plastic material. Alternatively, it is also possible that the conveyor belt 101 consists of a plurality of mutually movable elements that together form the conveyor belt.

[0029] According to the invention, the conveyor belt 101 comprises two rows 250 and 260 of openings 251 and 252, respectively, and 261, 262, and 263, wherein the rows of engagement openings 250 and 260 are preferably arranged parallel to each other but spaced apart (transversely to the transport direction T) in the conveyor belt 101. The rows 250 and 260 preferably extend parallel to the transport direction T, such that the distance of an engagement opening 251 to a center line of the conveyor belt 101 is equal to the distance of another engagement opening 252 of the same row 250 to this center line. The same applies to the engagement openings 261 to 263 of the second row 260 of engagement openings.

[0030] It is preferably provided that the rows 250 and 260 have a distance to an outer boundary of the conveyor belt transverse to the transport direction T that is smaller than the distance of the engagement openings of the rows 250 and 260 to a center line of the conveyor belt. Preferably, the distance to the outer boundary of the conveyor belt is at most 50% greater than the maximum dimension of the engagement openings in a transport plane that includes the transport direction T and runs through the conveyor belt. The area exposed between the rows 250 and 260 is thus available for product transport, whereby the risk of contamination of the engagement openings 251, 252, and 261 to 263 is minimized.

[0031] According to the invention, the engagement openings 251, 252, 261, 262 and 263 are arranged alternately in the transport direction T as seen from the product, so that in the transport direction T the Fig. In the illustration shown, for example, the engagement opening 263 first passes an imaginary measuring line M perpendicular to the transport direction, and then an engagement opening 252 from the other row 250 of engagement openings passes the imaginary measuring line. The distance between successive engagement openings 263 and 252 from different rows (here denoted by d) can, in principle, be arbitrary. However, it is preferred that the distance d (measured from the center point of the respective engagement opening to the center point of the respective other engagement opening of the other row in the transport direction T) is approximately half the distance between the adjacent engagement openings 261 and 262 of a row 260. The same applies to the alternating arrangement of the engagement openings with respect to the distances between the engagement openings 251 and 252 in the other row 250.Alternatively, it can also be provided that the distance d is between 20 and 80% of the distance between adjacent intervention openings 261 and 262 in one of the rows, preferably between 25% and 75%.

[0032] Furthermore, it may be provided, but is not required, that the distances L1 and L2 as well as P1 of immediately adjacent access openings in a row 250 or 260 are always identical for all pairs of immediately adjacent access openings in at least the same row, i.e., L1 = L2. It may also be provided that the distances of all pairs of immediately adjacent access openings of both rows 250 and 260 are identical, i.e., L1 = L2 = P1.

[0033] Furthermore, it can be provided that the angle α formed by two engagement openings of one of the two rows (here, row 260) and an engagement opening 251 of the other row 250 is as small as possible. This ultimately means that the distance of an engagement opening of one row to an engagement opening of the other row arranged directly upstream or downstream in the transport direction T is small compared to the width of the conveyor belt 101 perpendicular to the transport direction T, or small compared to the distance between the engagement openings of different rows. The ratio of the distance to the width can, for example, be at most 1 / 5, at most 1 / 10, or at most 1 / 20.

[0034] Since the conveyor belt 101 is driven by pulling the conveyor belt 101 in the transport direction T by means of the drive pulleys and the engagement elements provided on them (see also the description of the Fig. 3 to 5), a minimal angle α reduces shear forces that can act on the conveyor belt due to the alternating engagement of the engagement elements. It is particularly preferred if the angle α is less than 10°, less than 5°, or less than 2.5°.

[0035] Fig. Figure 3 shows an embodiment of the drive discs 131 and 132. In the embodiment shown here, the drive discs are not, or at least not rigidly, connected to each other, but are rotatably arranged on a drive axis or rotation axis R, but can, in principle, be rotated independently of each other about this axis R. Each of the drive discs is assigned a drive element 412 or 422, which can drive the respective drive disc 131 or 132, so that the drive disc is rotated about the drive axis R. The drive elements can, for example, be designed as servo motors or actuators.

[0036] Each drive disk comprises a number of engagement elements 311 in the circumferential direction. These are arranged in each drive disk at a distance r1 for drive disk 131 and a distance r2 for drive disk 132 from each other, preferably with the distances r1 and r2 being equal. The distances r1 and r2 are measured in the circumferential direction of the respective drive disk in a plane that is preferably perpendicular to the axis of rotation R.

[0037] The distances r1 and r2 are chosen such that the engagement elements 311 of the drive pulley 131 can engage in the engagement openings of a row 260 of engagement openings of the conveyor belt (see Fig. 2) and the engagement elements 321 of the drive disc 132 into the engagement openings of the other row 250 of engagement openings (see Fig. 2) engages. In this sense, as can be seen here, the drive discs 131 and 132 are arranged offset along the direction of rotation about the axis R such that the engagement elements of one drive disc do not run on a line parallel to the drive axis R with the engagement elements of the other drive disc.

[0038] The drive pulleys 131 and 132 are preferably arranged and / or driven such that they engage in the alternating engagement openings of the rows 250 and 260 and thus move the conveyor belt 101 (shown here only schematically) in the transport direction T. By providing separate drive elements 412 and 422, each of the drive pulleys can be controlled independently of the other drive pulley, in order to ensure, for example, that the forces transmitted to the conveyor belt are always the same.

[0039] Fig. 4 shows one for Fig. 3. Alternative embodiment. Here, the drive discs 471 and 472 are shown with the corresponding embodiments. Fig. The engagement elements 481 and 482 described in section 3 are rigidly connected to each other and rotatably mounted about the axis R. The rigid connection can be achieved, for example, by a common drive shaft or similar, ensuring that the drive discs 471 and 472 are arranged relative to each other in a manner that is rigid, i.e., does not change, at least in the direction of rotation about the axis R. In particular, it can be provided that the drive discs 471 and 472 are arranged on or connected to a drive roller 473 and / or are implemented as part of the drive roller 473.

[0040] In the embodiment shown here, exactly one drive element 490 (for example, a servo motor or actuator) is provided to drive the drive roller 473 and thus the drive discs 471 and 472, which reduces the number of components moving relative to each other as well as current-carrying components and can reduce the susceptibility to errors.

[0041] Fig.Figure 5 schematically shows a conveyor belt 101 and a drive pulley 131 with engagement elements and engagement openings 511 arranged on the conveyor belt. In this illustration, the engagement opening 511 extends only partially through the conveyor belt 101, so that there is no engagement opening on the side of the conveyor belt 101 opposite the drive pulley 131. This preferably results in the surface of the conveyor belt 101, on which the product is transported, being completely closed. This prevents contamination of the conveyor belt or openings in the conveyor belt by the product, which can improve hygienic conditions during product weighing, even during extended operation of the belt weigher.

[0042] As can be seen here, it can be provided that the engagement elements 531 and, accordingly, the engagement openings 511 have corresponding outer surfaces.

[0043] In particular, it can be provided that the engagement elements 531 and the engagement openings 511 have no edges and / or corners and / or have substantially convex curved surfaces (in the case of the engagement elements) or concave curved surfaces (in the case of the engagement openings). This prevents impacts due to tilting, which could negatively affect the measurement of the weight of the transported product. Alternatively or additionally, it can also be provided that the engagement openings 511 and / or the engagement elements 531 comprise a surface that comes into contact with the engagement element 531 or, correspondingly, with the engagement opening 511, and that consists of or comprises flexible material 512 (e.g., PU or rubber). This at least partially absorbs impacts exerted on the conveyor belt by the engagement elements or the drive pulleys, thus reducing the impulse transfer to the product in the weighing area. 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 10 2021 100 928 A1

[0003]

Claims

[1] Grinding belt scale (100) for weighing products (130), the grinding belt scale comprising a weighing area (102) for weighing products, a circulating conveyor belt (101) for conveying products into the weighing area and a drive device (103) for driving the conveyor belt, wherein the conveyor belt (101) comprises two rows (250, 260) of engagement openings (251, 252, 261, 262, 263), wherein the engagement openings are arranged alternately in the two rows as seen in a transport direction (T) of products (130), wherein the drive device (103) comprises two drive pulleys (131, 132), wherein each drive pulley comprises engagement elements (311, 321) and each drive pulley is designed to engage in exactly one of the two rows (250, 260) of engagement openings for driving the conveyor belt (101) is arranged. [2] Grinding belt scale (100) according to claim 1, wherein the two drive disks (131, 132) are rotatably mounted about a common drive axis (R). [3] Grinding belt scale (100) according to claim 1 or 2, wherein each of the two drive pulleys (131, 132) is assigned exactly one drive element (412, 422) of the grinding belt scale (100) and wherein the two drive pulleys can be moved synchronously with one another. [4] Grinding belt scale (100) according to claim 1 or 2, wherein the two drive pulleys (471, 472) are mechanically rigidly connected to one another. [5] Grinding belt scale (100) according to claim 4, wherein the two drive pulleys (471, 472) are arranged on a drive roller (473) and wherein the drive roller can be rotated by a drive element (490) of the grinding belt scale (100) for driving the conveyor belt (101). [6] Grinding belt scale (100) according to one of claims 1 to 5, wherein an angle (α) formed between two immediately adjacent engagement openings (262, 261) in a first of the two rows (250, 260) and the engagement opening (251) of the other of the two rows (250, 260) closest to these engagement openings is less than 10° or less than 5° or less than 2.5°. [7] Grinding belt scale (100) according to one of claims 1 to 6, wherein the engagement openings (511) are formed as recesses in the conveyor belt (101) pointing in the direction of the drive pulleys (131). [8] Grinding belt scale (100) according to one of claims 1 to 7, wherein at least two pairs of adjacent engagement openings (251, 252, 261, 262, 263) in one of the two rows (250, 260) have the same distance. [9] Grinding belt scale (100) according to one of claims 1 to 8, wherein an engagement opening (251) of one of the two rows (250, 260) is located in a position between two adjacent engagement openings (261, 262) of the other of the two rows (250, 260) and offset transversely to the transport direction (T), as seen in the transport direction (T) of the products (130), the distance (d) of the engagement opening in one of the two rows to one of the two adjacent engagement openings of the other of the two rows in the transport direction being between 25% and 75% of the distance between the two adjacent engagement openings. [10] Grinding belt scale (100) according to one of claims 1 to 9, wherein the engagement openings (511) and the engagement elements (531) are shaped such that engagement of the engagement elements into the engagement openings and / or removal of the engagement elements from the engagement openings can take place substantially smoothly. [11] Grinding belt scale (100) according to one of claims 1 to 10, wherein the engagement elements (531) and / or the engagement openings (511) comprise a contact surface for coming into contact with the engagement openings and / or the engagement elements, which contact surface consists of a flexible material or comprises a flexible material (512). [12] Method for weighing products (130) with a grinding belt scale (100) for weighing products, the grinding belt scale comprising a weighing area (102) in which a product is weighed, a circulating conveyor belt (101) for conveying product into the weighing area and a drive device (103) for driving the conveyor belt (101), wherein the conveyor belt comprises two rows (250, 260) of engagement openings (251, 252, 261, 262, 263), wherein the engagement openings (251, 252, 261, 262, 263) are arranged alternately in the two rows in a transport direction (T) of products, wherein the drive device (103) comprises two drive pulleys (131, 132), wherein each drive pulley comprises engagement elements (311, 321) and each drive pulley (131, 132) is arranged to engage in exactly one of the two rows (250, 260) of engagement openings (251, 252, 261, 262, 263) for driving the conveyor belt (101),the method comprising transporting at least one product (130) into the weighing area by the conveyor belt (101) and weighing the product in the weighing area, wherein during a movement of the conveyor belt in the transport direction of the product, an engagement element of one and the other of the two drive pulleys alternately engages one and the other of the two rows of engagement openings.

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