Method and device for packaging and sealing small-piece products on three continuously rotating working heads

Description

[0001] The present invention relates to a method and a device for packaging and sealing small-piece products such as chocolate pieces, stock cubes or stock tablets, hard caramels, soft caramels, washing machine or dishwasher tablets.

[0002] Intermittently operating packaging machines exist for wrapping stock cubes and tablets. These achieve outputs of up to 2,000 products per minute. However, due to the extremely short cycle times (60 ms), this places very high dynamic demands on the work components and leads to increased product stress due to impact and collision processes, as each processing step takes place within a product rest period (35-40 ms).

[0003] This output can hardly be increased, or only with considerable additional effort, since the increasing dynamic loads can no longer be adequately compensated for by, for example, lightweight construction measures. The process's susceptibility to product tolerances also remains problematic.

[0004] Currently, only very limited product tolerances can be processed at this high speed range. A further disadvantage is the high noise level already emitted by intermittent machines, which would increase with increasing output and would require even more complex shielding.

[0005] A proven alternative to intermittent operation is known from other industries such as chocolate, toffee, and hard candy. The application of a continuous operation principle significantly extends processing times, as each processing step is spread over several work cycles, keeping the product in constant motion without any intermediate stops. The processing operations take place during the movement.

[0006] EP 2 906 473 or WO 2014 / 056589 discloses a continuously operating, multi-lane packaging machine for small-sized products.

[0007] Another two-lane continuously operating packaging machine for stock cubes is known from EP 2 894 103. In this packaging machine, the products are fed in pairs on two lanes simultaneously, continuously positioned in pairs, and synchronized. A first single wheel (pick-up wheel) continuously receives products from both lanes and is fed packaging material (one section per lane) to the first wheel. A second single wheel (wrapping wheel) for both lanes creates the wrapping of each individual product on each lane from the packaging material. A third single wheel (tilting wheel) for both lanes transfers the products at the exit to an encapsulation module, where further folding processes and encapsulation (sealing) of the products on both lanes are carried out.

[0008] The present invention is based on the object of improving the known methods and devices for packaging and sealing small-sized products in order to achieve the most gentle processing of the products possible with the highest possible packaging performance or output.

[0009] To achieve this object, the invention provides the method according to claim 1 and the device according to claim 6.

[0010] A first aspect of the invention relates to a method for packaging and sealing small-sized products on three continuously rotating working heads, wherein each product is assigned a packaging material on the first working head, wherein each product with assigned packaging material is then transferred to the second working head, on which the product is packaged by folding the assigned packaging material around the product, wherein each packaged product is then transferred to the third working head, on which the packaging material assigned to each product is sealed. In this method, the folding and packaging processes are largely or completely carried out on the first two working heads, while the final third working head preferably serves exclusively for packaging sealing. Each working head preferably comprises the same number of working elements (e.g.gripper jaw pairs) and / or rotates at the same angular velocity around its axis of rotation. Preferably, the packaging material assigned to the product is sealed on the third working head on at least two sides of the product, preferably on two mutually facing sides of the product, particularly preferably on the two end faces of the product. Preferably, the product is fully packaged by folding the assigned packaging material around the product on the second working head, but at the latest on the third working head.

[0011] By applying the continuous operation principle to three rotating working heads, a significant increase in the output of a packaging machine can be achieved, particularly for pressure-sensitive products such as bouillon cubes and tablets. At the same time, product stress, which is crucial for these sensitive products, can be reduced and kept within acceptable limits. Furthermore, larger product tolerances can be processed at high speed. The method according to the invention ensures optimal product flow through the packaging machine, taking into account contamination processes and thermal processes. The complexity is limited to three continuously rotating working heads before the products are transferred, for example, to a discharge conveyor. The essential processing steps required for packaging are carried out in these three heads.

[0012] In order to solve accessibility problems, especially when there are multiple tracks, all heads are preferably mounted in a cantilevered frame at the rear.

[0013] The packaging machine according to the invention, particularly in the design for stock cubes and tablets, enables an output of up to 3000 pieces per minute.

[0014] Advantageous developments of the invention are the subject matter of the dependent claims.

[0015] It may be advantageous to package the products on the three continuously rotating rotary heads in multiple lanes on parallel product lines. This further increases the packaging performance of the method according to the invention. A multi-lane packaging machine is known from EP 2 906 473, the contents of which are incorporated herein by reference.

[0016] It can prove useful if the packaging material assigned to each product is sealed on the third working head laterally and optionally on the product base, preferably with the working element holding the product, wherein the working element preferably holds the product for at least one full rotation of the third working head about its axis of rotation, wherein the working element is particularly preferably heated by induction, most preferably heated in a state in which the working element is not holding a product. Corresponding sealing heads are known from DE 10 2018 209 185.4 and DE 10 2019 210 354.5, the contents of which are incorporated herein by reference. Using a corresponding sealing head, the sealing time can be extended to such an extent that sealing can take place within the continuous movement of the rotating head. The lateral sealing of the packaging material assigned to the product preferably takes place on the two end faces of the product.

[0017] It can be advantageous if the product transfer between the first work head and the second work head and / or the product transfer between the second work head and the third work head takes place exactly or essentially tangentially to the rotation axes of the respective work heads. This avoids rapid changes of direction and quality-reducing lateral acceleration of the product perpendicular to the direction of movement.

[0018] However, it may also be practical if the packaging of the product with packaging material comprises at least one of the following steps, of which steps A to D are preferably carried out in the specified order, preferably on the first working head, and / or steps E to J are preferably carried out in the specified order, preferably on the second working head: Step A: Holding the product across its width or between its end faces. This makes the front and rear side surfaces of the product (aligned with surface normals in and against the direction of movement or tangential to the pitch circle) as well as the upper and lower side surfaces (aligned with surface normals radially inward and outward to the rotation axis of the working head) accessible for wrapping with packaging. The product is preferably held by a working element or pair of gripper jaws, which clamps the product between its end faces. Step B: Assigning a packaging material to the product. The packaging material is preferably fed to the product from the front of the product, i.e., the side of the product leading in the direction of movement, so that the product essentially "runs into" the provided packaging material and carries it along in the movement direction.The packaging material is preferably held in contact with the product using packaging pliers. Step C: Arranging the packaging material in an L-shape around the product. The L-shape of the packaging material preferably covers the front and bottom, or the side surfaces leading in the direction of movement and the radially outward-facing side surfaces of the product. Step D: Arranging the packaging material in a U-shape around the product. The U-shape of the packaging material preferably covers the front, bottom and rear, or the side surfaces leading in and against the direction of movement, as well as the radially outward-facing side surfaces of the product. In this state, the product is preferably transferred to the downstream working head. Step E: Holding the product and the packaging material assigned to the product along their length so that the end faces of the product are exposed, and / or placing one leg of the U-shaped packaging material against the product.The product and the packaging assigned to the product are preferably held lengthwise by a working member or pair of gripper jaws, which clamps the product and the packaging assigned to the product lengthwise, i.e., along the product axis aligned along the direction of movement or tangentially to the pitch circle. Step F: Forming a first inner end fold from the packaging material projecting over each end of the product and folding this onto the end of the product. The order of steps F and G can be reversed. Step G: Arranging the packaging in tubular form around the product. This closes the packaging around the circumference of the product in a plane aligned perpendicular to the axis of rotation of the rotary head. Step H: Forming a second inner end fold from the packaging material projecting over each end of the product and folding this onto the end of the product.Ideally, the packaging material overhang is selected such that a small section of the product's end face is still exposed between the first and second inner end folds. The order of steps H and I can be swapped. Step I: Forming a first outer end fold from the packaging material protruding over each end face of the product and folding this onto the first and, if applicable, second inner end fold on each end face of the product. Step J: Forming a second outer end fold from the packaging material protruding over each end face of the product and folding this onto the first and second inner end folds as well as the first outer end fold on each end face of the product. .

[0019] Steps F to J are preferably carried out on both end faces of the product simultaneously, preferably symmetrically to the product center. With rectangular end faces, the packaging overhang is preferably selected to be large enough to ensure secure coverage of the two outer end folds. With a square end face, these folds preferably only abut one another or overlap minimally, whereby the overlap cannot be significantly increased. In the described embodiment - when the products are transferred from the second to the third working head with sufficient coverage of the last two folds - the step sequence FGIHJ should preferably be used. The first and last folds are preferably connected to one another to fix the packaging in the folded state.

[0020] The first and / or second inner front fold(s) is / are preferably folded over each of the two shorter side edges of a rectangular front side of the product.

[0021] The first and / or second outer front fold(s) is / are preferably folded over each of the two longer side edges of a rectangular front side of the product.

[0022] Another aspect of the present invention relates to a device for packaging and sealing small-sized products on three continuously rotating working heads, comprising: A first work head, which is designed to continuously rotate and assign a packaging material to each product. A second work head, which is designed to continuously rotate and receive each product with its associated packaging material from the first work head and package the product by folding the associated packaging material around the product. A third work head, which is designed to continuously rotate and receive each packaged product from the second work head and seal the packaging material assigned to each product.

[0023] The same advantages arise that were previously mentioned in connection with the method according to the invention.

[0024] Preferably, the second working head and / or the third working head is / are designed to completely package each product by folding the associated packaging material around the product.

[0025] Preferably, the third working head is designed to seal the packaging material assigned to each product on at least two sides of the product, preferably on two mutually opposing sides of the product, particularly preferably on the two end faces of the product.

[0026] It may be useful if the device has a product feeder for feeding the products to the first working head, preferably tangentially to its pitch circle, preferably on a plurality of parallel product paths. This optimally positions the products for subsequent product pick-up by the first working head. Preferably, all products to be picked up are positioned and oriented identically with respect to the respective working element of the first working head at the pick-up station. This allows a consistent packaging result to be achieved for each product.

[0027] It may prove practical if the device includes a product discharge device to remove the products from the third working head, preferably exactly or essentially tangentially to its pitch circle. This ensures that the products are discharged from the packaging device particularly gently.

[0028] According to the invention, the pitch circles of two or three of the working heads overlap when projected vertically and / or horizontally. This makes the design of the packaging device particularly compact. The pitch circle typically describes the path along which the product center is guided around the rotational axis of the working head. Alternatively, the pitch circle describes a circle around the rotational axis of the product-guiding rotary head, passing through the product center at the time of product pick-up and / or discharge.

[0029] According to the invention, the rotational axis of the third working head is arranged above the rotational axis of the second working head and above the rotational axis of the first working head. This places the sealing station at the top of the packaging process. The waste heat from the working elements rises upwards and therefore does not affect the first and second working heads below them, nor the packaging processes performed on them. Terms and definitions

[0030] The term "small-piece products" refers in particular to small-piece food products such as chocolate pieces, bouillon cubes or bouillon tablets, hard caramels such as candies, soft caramels such as chewy candies, but also small-piece consumer goods such as washing machine or dishwasher tablets. The small-piece products preferably have a cuboid shape, especially a cube shape, or at least a rectangular base. However, it is also possible to package other product shapes using the method according to the invention.

[0031] The term "fully packaged" means that after completion of all folding processes, all side surfaces, including the end faces, of the product are covered with packaging material, and that preferably no further folding or packaging steps follow within the scope of the device and method according to the invention.

[0032] The product is preferably packaged hermetically in its fully sealed state. The packaging is preferably hermetically sealed, and the overlapping packaging sections are hermetically sealed. The length, width, height, and sides of the product are measured in millimeters.

[0033] The terms length, width and height of the product are usually defined in relation to its direction of movement.

[0034] The length of the product is measured along the direction of movement, i.e. the longitudinal axis of the product runs along the direction of movement or tangentially to the pitch circle of the product-guiding working head.

[0035] The width of the product is measured perpendicular to the direction of movement, i.e. the transverse axis of the product is perpendicular to the direction of movement and parallel to the axis of rotation of the product-guiding working head.

[0036] The height of the product is also measured perpendicular to the direction of movement, i.e. the vertical axis of the product runs perpendicular to the direction of movement and radial to the axis of rotation of the product-guiding working head.

[0037] The product base is preferably the side of the product on which the overlap between the inner and outer folds occurs or the side of the product on which the packaging material overlaps to form the packaging tube.

[0038] The end faces of the product are preferably the sides of the product whose surface normals are aligned parallel to the axis of rotation of the product-guiding working head or which lie in planes aligned parallel to the path of movement of the product and / or the sides of the product between which the product is held clamped in the first and / or third working head and / or the sides of the product onto which the side folds of the packaging are or are folded.

[0039] In the first working head, the product is preferably gripped across its width, in the second working head, preferably across its length, and in the third working head, preferably across its width again. Short description of the characters:

[0040] They show: Fig. 1 a schematic view of the packaging method according to the invention and the packaging device according to the invention, which has a conveyor belt as a feeding device, a gripper head as a first working head, a packing head arranged above it as a second working head and a sealing head arranged above it as a third working head as well as a further conveyor belt as a discharge device. Fig. 2 a schematic sequence of the packaging steps of the product according to the method according to the invention. Detailed description of the preferred embodiments:

[0041] The invention is described below using the preferred embodiment with reference to the figures.

[0042] To implement a continuous packaging process, the packaging device 1 according to the preferred embodiment of the invention comprises a conveyor belt 2 as a product feed, a gripper head 3 as the first working head, a packing head 4 arranged above it as the second working head and a sealing head 5 arranged above it as the third working head, as well as a discharge belt 6 as the removal device. In addition, the packaging device 1 has an inductor 7 for inductively heating the working elements of the sealing head 5 and a packaging material feed 8, which feeds a packaging material or a packaging material blank V for each product P to the gripper head 3 exactly or essentially radially to its pitch circle T3 or radially to the circular segment-shaped movement paths P1, P2 of the products P on the first working head 3.

[0043] The products P are guided through the packaging device 1 in continuous motion, without intermediate stops, via various stations S1-S11. This can be done in one, two, or multiple lanes. The transfer of the products P from one to the subsequent work head 3, 4, 5 occurs in a tangential direction along the respective product lane P1, P2. The essential features of the invention are as follows: Product feed / conveyor system 2

[0044] In the conveyor device 2, a continuous product feed takes place in a regular product sequence, whereby the position of the products is synchronized with the subsequent first working head or gripper head 3. First working head - gripper head 3 (stations S1 to S5)

[0045] In the gripper head 3, individual products P are picked up by a working element, here by laterally arranged grippers, from the conveyor device 2 in a tangential direction. The feeding of a packaging material V can occur approximately in a radial direction, but also tangentially. The packaging material V is positioned next to the product P to be packaged (see Fig. 2b ) and secured with packaging pliers (not shown). The packaging material V is then folded onto the bottom of the product P (see Fig. 2c ) by optionally guiding the products P past a guide arch (not shown). Second working head - packing head 4 (stations S5 to S10)

[0046] The packing head 4 receives the products P with the associated packaging material V tangentially in the movement from the gripper head 3 by a working element, thereby grippers arranged at the front and rear in the direction of movement. The production of the complete fold wrap is carried out by forming a tubular wrapping from the packaging material V and folding the packaging overhang onto the end sides of the product in the Fig. 2 shown views (d) to (j).

[0047] The packing head 4 has movable folding elements (bottom folder, front folder) at each station, which, in conjunction with external folding elements (e.g. folding arch, folding switches, folding head), realize the folding. Third working head - Sealing head 5

[0048] The sealing head 5 receives the products P tangentially from the packing head 4 through a working element, namely grippers arranged laterally in the direction of movement. The grippers or specially designed elements fix the (preferably lateral) folds by gripping. The grippers are heated, so that the packaging V is sealed simultaneously during gripping.

[0049] To extend the sealing time, the sealing head 5 can alternatively be designed so that the products are held in it for more than one head revolution and sealed accordingly. A corresponding sealing head 5 is disclosed in German patent application DE 10 2019 210 354, the contents of which are incorporated herein by reference. Discharge device 6 or discharge line 6:

[0050] After the products P are sealed and the fold cannot reopen, the products P are transferred in a tangential direction to a continuously moving discharge line 6. Additional functions can be implemented in the discharge line 6 if required. These can include: Sealing device for the longitudinal seam Product quality detection Rejection of defective products Packaging material feed 8

[0051] The packaging material V is continuously unwound from a reel by a transport device. A cutting device separates individual packaging sections V and transfers them to the gripper head 3. A changeover device is used to change from an empty to a full reel during unwinding to avoid interrupting the processing. In a two- or multi-lane version of the machine, the packaging material feed preferably also includes longitudinal separation into a corresponding number of packaging webs and their diversion onto the respective product throughput lane, so that two or more packaging sections V are then provided simultaneously.

[0052] It is essential that the functions mentioned are executed in pairs simultaneously for each track P1, P2 in the case of a two-track design, and in parallel in the case of several tracks P1, P2 in a corresponding variety.

[0053] The product flow essentially takes place from bottom to top and from a feed side to a discharge side facing away.

[0054] The core concept of the invention is the realization of a packaging process with maximum output of up to 3000 units / min, combined with reasonable requirements for processable product tolerances and processing that is as gentle as possible to the product. The proposed functional principle of a continuously operating machine, particularly in the two-lane design, meets this requirement. Furthermore, such an arrangement ensures excellent accessibility to all process-relevant functional points with minimal space requirements. Environmental aspects, such as reducing noise emissions and vibration, are also taken into account. List of reference symbols

[0055] 1Packaging device 2Product feed or conveyor 3Gripper head 4Packing head 5Sealing head 6Product discharge or conveyor 7Inductor 8Packaging material feed F1, F2Inner front folds F3, F4Outer front folds PProduct P1, P2Product tracks S1-S11Folding and sealing stations T3, T4, T5Partial circles of the working heads VPackaging material X3, X4, X5Rotation axes of the working heads

Claims

1. Method for packaging and sealing small products (P) on three continuously rotating working heads (3, 4, 5), where each product (P) is assigned a packaging material (V) on the first working head (3), each product (P) with assigned packaging material (V) is then transferred to the second working head (4), where the product (P) is packaged by folding the assigned packaging material (V) around the product (P), wherein each packaged product (P) is then transferred to the third working head (5), on which the packaging material (V) assigned to each product (P) is sealed, wherein the partial circles (T3, T4, T5) of two or three of the working heads (3, 4, 5) overlap when projected in the vertical direction and / or in the horizontal direction, characterized in that the second working head (4) is arranged above the first working head (3) and the axis of rotation (X5) of the third working head (5) is arranged above the axis of rotation (X4) of the second working head (4) and above the axis of rotation (X3) of the first working head (3).

2. Method according to claim 1, characterized in that the products (P) are packaged on the three continuously rotating rotary heads (3, 4, 5) in multiple lanes on parallel product lanes (P1, P2).

3. Method according to one of the preceding claims, characterized in that the packaging material (V) assigned to each product (P) is sealed on the third working head (5) at the side and, if necessary, on the bottom of the product, preferably with the working member holding the product (P), wherein the working member preferably holds the product (P) for at least one full revolution of the third working head (5) about its axis of rotation (X5), wherein the working member is particularly preferably heated by induction, and most preferably heated in a state in which the working member does not hold any product.

4. Method according to one of the preceding claims, characterized in that that the product transfer between the first working head (3) and the second working head (4) and / or the product transfer between the second working head (4) and the third working head (5) takes place exactly or substantially in a tangential direction to the axes of rotation (X3, X4, X5) of the respective working heads (3, 4, 5).

5. Method according to one of the preceding claims, characterized in that the packaging of the product (P) with packaging material (V) comprises at least one of the following steps, of which steps A to D are preferably performed in the specified order, preferably on the first working head (3), and / or steps E to J are preferably performed in the specified order, preferably on the second working head (4): a. step A: holding the product (P) across its width or between its end faces. b. step B: assigning a packaging material (V) to the product (P). c. step C: arranging the packaging material (V) in an L-shape around the product (P). d. step D: arranging the packaging material (V) in a U-shape around the product (P). e. step E: holding the product (P) and the packaging material (V) assigned to the product (P) across the length so that the front sides of the product (P) are exposed, and / or placing one leg of the U-shaped packaging material (V) against the product (P). f. step F: forming a first inner front fold (F1) from the packaging material (V) protruding over each front side of the product (P) and fold it onto the front side of the product (P). g. step G: arranging the packaging material (V) in a tube shape around the product (P). h. step H: forming a second inner end fold (F2) from the packaging material (V) protruding beyond each end face of the product (P) and folding it onto the end face of the product (P). i. step I: forming a first outer end fold (F3) from the packaging material (V) protruding beyond each end face of the product (P) and fold it onto the first and, if applicable, second inner end folds (F1, F2) on each end face of the product (P). j. step J: forming a second outer end fold (F4) from the packaging material (V) protruding beyond each end face of the product (P) and folding it onto the first and second inner end folds (F1, F2) and the first outer end fold (F3) on each end face of the product (P).

6. Device (1) for packaging and sealing small products (P) on three continuously rotating working heads (3, 4, 5), comprising: a. a first working head (3) which is designed to continuously rotate and assign a packaging material (V) to each product (P). b. a second working head (4) which is designed to continuously rotate and take each product (P) with the assigned packaging material (V) from the first working head (3) and to package the product (P) by folding the assigned packaging material (V) around the product (P). c. a third working head (5) which is designed to continuously rotate and take each packaged product (P) from the second working head (4) and seal the packaging material (V) assigned to each product (P); wherein the partial circles (T3, T4, T5) of two or three of the working heads (3, 4, 5) overlap when projected in the vertical direction and / or in the horizontal direction; characterized in that the second working head (4) is arranged above the first working head (3) and the axis of rotation (X5) of the third working head (5) is arranged above the axis of rotation (X4) of the second working head (4) and above the axis of rotation (X3) of the first working head (3).

7. Device (1) according to claim 6, characterized in that the device (1) has a product feed (2) for feeding the products (P) to the first working head (3), preferably tangentially to its partial circle (T3), preferably on a plurality of parallel product paths (P1, P2).

8. Device (1) according to claim 6 or 7, characterized in that the device (1) has a product discharge (8) for discharging the products (P) from the third working head (5), preferably exactly or substantially tangentially to its pitch circle (T5).