Rotary welding device and related method

Abstract

To provide a rotary device capable of responding to a variation in a working circumference without an operator intervening manually to satisfy necessity to vary a radial position of a plurality of welding units, which are configured to weld a continuous web while a rotary part rotates through a predetermined circular arc, relative to an axis of rotation of a rotary element to vary weld spacing.SOLUTION: A rotary device for welding a continuous web comprises: a rotary means 2 rotating about an axis of rotation 2a; a plurality of welding units 3 mounted on the rotary means 2 so as to be angularly spaced from each other; and movement means configured to vary radial positions of the plurality of welding units 3 by moving the plurality of welding units 3 toward the axis of rotation 2a of the rotary means 2 or away from the axis of rotation 2a. The rotary device is supported by a load-bearing structure 8 connected to the plurality of welding units 3 so as to correspond to radial movement of the plurality of welding units 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rotary welding apparatus and related methods.

[0002] In particular, the apparatus according to the present invention is configured to weld a continuous web along a direction transverse to the web feed direction according to a predetermined welding interval.

[0003] For example, the apparatus of the present invention is configured to weld a continuous web to make absorbent articles or diapers, and in particular to weld the side gathers of pant-type diapers.

[0004] In other embodiments, the apparatus of the present invention is configured to weld a continuous web for manufacturing pouches that contain food and confectionery products such as chocolate or confections, beverage bottles and brick packs, solid, liquid, and semi-solid foods, products of the tobacco industry, products of the cosmetics industry, products of the pharmaceutical industry, products of the personal care and home care industries.

[0005] In particular, the continuous web can be used to make packs or pouches for containing liquid or solid products.

Background Art

[0006] Prior art apparatuses for welding absorbent articles typically include a rotating part on the circumferential surface of which a continuous web of absorbent articles to be welded is disposed.

[0007] A plurality of welding units are configured to weld the continuous web while the rotating part rotates through a predetermined arc.

[0008] These welding units are angularly spaced from each other about the axis of rotation of the rotating part.

[0009] The welding interval of the continuous web is determined by the angular distance between one welding unit and the adjacent welding unit.

[0010] For a continuous web, the welding interval is defined by the linear distance between two different welds arranged in sequence in the longitudinal development direction of the web.

[0011] To optimize costs, there is an increasing need to manufacture different product formats by changing the welding interval using the same rotary welding device.

[0012] To change the welding interval of the device, it is necessary to change the radial position of the welding unit with respect to the rotation axis of the rotating element so as to determine a working circumference along which the desired welding interval can be obtained.

[0013] Changing the working circumference means changing the arc between each welding unit and the adjacent welding unit. The element supporting the continuous web must be arranged along that arc to ensure that the web part welded by the corresponding welding unit is under tension.

[0014] In this regard, there is a need to develop an element for supporting the continuous web that can respond to changes in the working circumference without operator manual intervention, avoiding the need for manual removal and reassembly of parts, thus speeding up the work and ensuring that the part of the continuous web to be welded is correctly tensioned.

[0015] In fact, it should be noted that if parts are manually removed during a format change performed manually, the continuous web arranged on the support element is cut, and after reassembling the parts, the continuous web needs to be wound around the support element again.

[0016] In practice, this is a very time-consuming process due to the related operations.

[0017] Regarding the change of the working circumference, there is a need to be able to change this circumference without interruption in order to create standard and non-standard formats.

Summary of the Invention

[0018] To meet this need, there is provided a rotating device for welding a continuous web, preferably for manufacturing absorbent articles or for manufacturing a pouch for containing liquid or solid products, the rotating device comprising rotating means that rotate around its rotation axis, and a plurality of welding units that are attached to the rotating means so as to be angularly spaced apart from each other for welding the continuous web.

[0019] It should be noted that the angular distance between the welding units defines the welding interval.

[0020] Each welding unit is configured to move from a non-operating position to an operating position and from the operating position to the non-operating position during the rotation of the rotating means.

[0021] The moving means is configured to change the radial position of the welding unit by moving the welding unit towards or away from the rotation axis of the rotating means.

[0022] By changing the radial position of the welding unit, the welding interval of the continuous web can be changed.

[0023] A first support element and a second support element for supporting the continuous web, which are respectively arranged upstream and downstream of the same welding unit with respect to the rotation direction of the rotating means, keep the continuous web under tension when the welding unit is in the operating position.

[0024] The first support element and the second support element associated with each corresponding welding unit are supported by a load-bearing structure extending around the rotation axis of the rotating means.

[0025] The load-bearing structure is connected to the welding unit such that the radial movement of the welding unit corresponds to the movement of a first support element and a second support element towards and away from the axis of rotation of the rotating means.

[0026] Advantageously, the simultaneous movement between the welding unit and the support element of the continuous web enables the management of format changes of the rotating device without the assistance of an operator.

[0027] At least one first support element and at least one second support element associated with each corresponding welding unit are arranged in pairs between two welding units such that the continuous web wound around the first support element and the second support element defines a polygonal outer perimeter whose length is variable according to the position of the first support element and the second support element with respect to the axis of rotation of the rotating means.

[0028] Advantageously, by arranging the first support element and the second support element in pairs between one welding unit and the next welding unit in the direction of rotation of the rotating means, the continuous web can be arranged along a polyline that globally defines the outer perimeter of the polygon. This enables the management of the support elements at each position with respect to the axis of rotation of the rotating means without problems of space or interference between the support elements.

[0029] As shown in detail in FIGS. 3 and 4, the load-bearing structure comprises a mounting body for each pair of at least one support element and at least one second support element, and a connection body for each connecting the load-bearing structure to the corresponding welding unit.

[0030] Advantageously, the connection body connecting the load-bearing structure to the welding unit enables the entire load-bearing structure to be moved when the welding unit is moved.

[0031] The mounting body is movably coupled to the respective corresponding connection bodies that are different from each other.

[0032] Each mounting body is movable toward and away from the corresponding connection body.

[0033] Advantageously, each mounting body can move from an initial position of minimum length to a final position of maximum length. In this way, the first support element and the second support element can be arranged at a minimum position closest to the rotation axis of the rotating means and a maximum position farthest from the rotation axis so as to support the continuous web such that the welding interval ranges from the minimum length to a maximum length considerably longer than the minimum length.

[0034] For example, with respect to the welding interval sizes obtained in the case of absorbent hygiene products, this corresponds to a welding interval of minimum length for size S and a welding interval of maximum length for size XL, and in total at least four welding interval lengths correspond to sizes S, M, L, and XL.

[0035] For example, FIG. 1 shows a rotating device configured in a minimum length.

[0036] For example, FIG. 2 shows a rotating device configured in a maximum length.

[0037] Each mounting body includes a first element and a second element, each of which is connected to the corresponding connection body.

[0038] Each first element and each second element of the mounting body include a first portion slidably coupled to a corresponding connection body of a load-bearing structure along a radial direction with respect to the rotation axis of the rotating means.

[0039] Advantageously, by sliding the first element and the second element of each mounting body, the positions of the corresponding first support element and second support element can be translated.

[0040] Each first element and each second element of the mounting body include a second portion slidably coupled to a corresponding first portion along a circumferential direction with respect to the rotation axis of the rotating means, as shown in FIG. 4.

[0041] The first support element and the second support element are supported by the second portions of the first and second elements of the mounting body.

[0042] Advantageously, by further sliding the second portion and the first portion relative to each other, the mounting body can be radially expanded to counteract the welding units moving away from each other during the radial movement away from each other.

[0043] Each mounting body supports a respective housing member for accommodating the corresponding first support element and second support element.

[0044] The first support element and the second support element supported by the same housing member are associated with respective welding units that are different from each other.

[0045] The first support element and the second support element are arranged on the corresponding housing member at a constant distance. More specifically, they are arranged at the first end and the second end of the housing member.

[0046] This constant distance defines a side of a constant length of the outer perimeter of a polygon obtained by the radial displacement of the housing member.

[0047] Each housing member is movably coupled to the corresponding mounting body of the load-bearing structure, in particular to the second portions of the corresponding first and second elements.

[0048] As shown in FIG. 5, the load-bearing structure is slidably coupled to a mounting frame connected to a rotating means.

[0049] The first support element and the second support element are in the form of rollers and each rotates about its respective axis of rotation.

[0050] Advantageously, the roller structure makes it possible to define a contact zone with the continuous web along a line transverse to the longitudinal development of the web and to define each corner of the polyline obtained by winding the web around the roller.

[0051] The holding means are provided for holding a portion of the continuous web that is not intended to be welded.

[0052] The holding means comprise a first flexible element and a second flexible element that extend around the axis of rotation of the rotating means and between which the above-mentioned portion of the continuous web is arranged.

[0053] Advantageously, the first flexible element and the second flexible element for holding a portion of the continuous web not involved in welding facilitate the maintenance and cleaning of the device when the continuous web needs to come out of the device.

[0054] The invention also relates to a rotating method for welding a continuous web, preferably for manufacturing absorbent articles, or for manufacturing a pack or pouch for containing a liquid or solid product, wherein a plurality of welding units for welding the continuous web are arranged around a common axis of rotation so as to be angularly spaced from each other.

[0055] The method includes a step of conveying the continuous web around the axis of rotation and a step of welding the continuous web during the step of conveying the continuous web.

[0056] Depending on the resulting welding intervals, the method includes a step of changing the radial position of the welding unit and, simultaneously, a step of changing the position of the continuous web towards or away from the axis of rotation. The continuous web extends around the axis of rotation so as to define a polygonal outer periphery of variable length depending on the radial position of the continuous web with respect to the axis of rotation so as to be adaptable to the change in the radial position of the welding unit.

Brief Description of the Drawings

[0057] Further features and advantages of the present invention will become more apparent in the following non-limiting description of some preferred embodiments of the rotary welding apparatus, as schematically shown in the accompanying drawings.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0058] Reference numeral 1 indicates a rotating device for welding the continuous web 4 according to the present invention.

[0059] Preferably, the rotary welding apparatus 1 manufactures an absorbent article or a part thereof, or a pouch for containing a liquid or solid product.

[0060] The rotating device 1 includes a rotating means 2 that rotates about its rotation axis 2a, and a plurality of welding units 3 attached to the rotating means 2 so as to be angularly spaced apart from each other for welding the continuous web 4.

[0061] Preferably, the rotating means 2 includes a cylindrical drum attached to a shaft that rotates around the rotation axis 2a.

[0062] Each welding unit 3 is configured to move from a non-operating position to an operating position and from the operating position to the non-operating position during the rotation of the rotating means 2.

[0063] With respect to their rotation around the rotation axis 2a, the welding units 3 move from the non-operating position to the operating position within the arc of the working circumference.

[0064] The length of the arc of the working circumference is a function of the time required to weld the continuous web 4.

[0065] The moving means 5 is configured to change the radial position of the welding unit 3 by moving the welding unit 3 towards or away from the rotation axis 2a of the rotating means 2.

[0066] In other words, the moving means 5 translates the welding unit 3 towards or away from the rotation axis 2a of the rotating means 2.

[0067] The moving means 5 simultaneously moves all the welding units 3 towards or away from the rotation axis 2a of the rotating means 2.

[0068] For each welding unit 3, at least one first support element 6 and at least one second support element 7 for supporting the continuous web 4 are arranged upstream and downstream of the welding unit 3 in the rotation direction of the rotating means 2, respectively.

[0069] The first support element 6 and the second support element 7 are in the form of rollers 23 and each rotates around its respective rotation axis 23a.

[0070] The first support element 6 and the second support element 7 are capable of keeping the continuous web 4 under tension when the welding unit 3 is in the operating position.

[0071] The first support element 6 and the second support element 7 associated with each corresponding welding unit 3 are supported by a load-bearing structure 8 connected to the welding unit 3.

[0072] The radial movement of the welding unit 3 corresponds to the movement by the load-bearing structure 8 and moves the first support element 6 and the second support element 7 towards and away from the rotation axis 2a of the rotating means 2.

[0073] The load-bearing structure 8 enables all the welding units 3 to be simultaneously moved together with a first support element 6 and a second support element 7 that support the continuous web 4 so as to perform a format switching operation without the help of an operator.

[0074] The first support element 6 and the second support element 7 associated with each corresponding welding unit 3 are arranged in pairs between two welding units 3.

[0075] In this way, the continuous web 4 wound around the first support element 6 and the second support element 7 defines a polygonal outer periphery with a variable length according to the positions of the first support element 6 and the second support element 7 with respect to the rotation axis 2a of the rotating means 2.

[0076] Advantageously, the polygonal configuration enables the formation of a function of supporting the continuous web 4 along the minimum and maximum polygonal lengths, regardless of the sizes of the first support element 6 and the second support element 7.

[0077] The load-bearing structure 8 includes a mounting body 9 for mounting the first support element 6 and the second support element 7.

[0078] Each mounting body 9 supports a pair of at least one first support element 6 and one second support element 7.

[0079] The load-bearing structure 8 includes a plurality of connection bodies 10, and each connection body 10 connects the load-bearing structure 8 to the corresponding welding unit 3.

[0080] In order to be able to transition from a minimum-length configuration to a maximum-length configuration, the mounting body 9 is movably coupled to the corresponding respective connection bodies 10 that are separate from each other.

[0081] Each mounting body 9 is movable towards and away from the corresponding connection body 10.

[0082] In other words, each mounting body 9 is capable of translational movement toward and away from the corresponding connection body 10.

[0083] Each mounting body 9 includes a first element 11 and a second element 12 connected to the corresponding connection body 10.

[0084] Each first element 11 and each second element 12 of the mounting body 9 include a first portion 13 slidably connected to the corresponding connection body 10 of the load-bearing structure 8 along a radial direction toward and away from the rotation axis 2a of the rotating means 2.

[0085] In other words, the first portions 13 of each first element 11 and each second element 12 perform translational movement with respect to the connection body 10 of the load-bearing structure 8 toward and away from the rotation axis 2a of the rotating means 2.

[0086] Each first element 11 and each second element 12 of the mounting body 9 include a second portion 14 slidably connected to the corresponding first portion 13 along a circumferential direction with respect to the rotation axis 2a of the rotating means 2, and the second portions 14 of the first element 11 and the second element 12 move toward and away from each other.

[0087] The first support element 6 and the second support element 7 are supported by the second portions 14 of the first element 11 and the second element 12 of the mounting body 9.

[0088] Each mounting body 9 supports respective housing members 15 for accommodating the corresponding first support element 6 and second support element 7.

[0089] More specifically, the first support element 6 and the second support element 7 supported by the same housing member 15 are associated with respective welding units 3 that are different from each other.

[0090] The first support element 6 and the second support element 7 are arranged at a certain distance on the corresponding housing member 15. More specifically, they are arranged at the first end 15a and the second end 15b of the housing member 15.

[0091] Each housing member 15 is movably coupled to the respective mounting body 9 of the load-bearing structure 8, specifically to the second portion 14 of the respective first element 11 and second element 12.

[0092] The load-bearing structure 8 is slidably coupled to a mounting frame 16 connected to the rotating means 2.

[0093] The mounting frame 16 includes a plurality of guides 22 along which the load-bearing structure 8 slides.

[0094] The rotary welding device 1 includes holding means 17 for holding a portion of the continuous web 4 that is not intended to be welded.

[0095] The holding means 17 includes a first flexible element 18 and a second flexible element 19 that extend around the rotation axis 2a of the rotating means 2 and between which a portion of the continuous web 4 that is not welded is disposed.

[0096] In order to adapt the lengths of the first flexible element 18 and the second flexible element 19 to changes in the position of the welding unit 3 of the first support element 6 and the second support element 7 relative to the rotation axis 2a of the rotating means 2, the first tensioning means 20 and the second tensioning means 21 are each configured to change the lengths of the first flexible element 18 and the second flexible element 19.

[0097] The present invention also aims at a rotary method for welding a continuous web, preferably for manufacturing absorbent articles or for manufacturing a pouch for containing liquid or solid products. A plurality of welding units 3 for welding the continuous web 4 are arranged around a common rotation axis 2a so as to be angularly spaced from each other.

[0098] The method includes a step of conveying a continuous web 4 around a rotation axis 2a and a step of welding the continuous web 4 during the step of conveying the continuous web 4.

[0099] Depending on the resulting welding interval, the method includes a step of varying the welding interval, which step is a step of varying the radial position of the welding unit 3 and which includes, at the same time, a step of varying the position of the continuous web 4 towards or away from the rotation axis 2a.

[0100] The step of varying the position of the continuous web 4 includes arranging the continuous web 4 around the rotation axis 2a so as to define an outer periphery of a polygon having a variable length depending on the radial position of the continuous web 4 with respect to the rotation axis 2a so as to be adaptable to the variation in the radial position of the welding unit 3.

Claims

1. A rotating device for welding a continuous web, comprising: Rotating means (2) that rotates around its rotation axis (2a); A plurality of welding units (3) for welding the continuous web (4), which are attached to the rotating means (2) so as to be angularly spaced from each other, and each welding unit (3) is configured to move from a non-operating position to an operating position and from the operating position to the non-operating position during the rotation of the rotating means (2); Moving means (5) configured to change the radial position of the plurality of welding units (3) by moving the plurality of welding units (3) towards or away from the rotation axis (2a) of the rotating means (2); At least one first support element (6) and at least one second support element (7) respectively arranged upstream and downstream of the same welding unit (3) with respect to the rotation direction of the rotating means (2) for supporting the continuous web (4), and the at least one first support element (6) and the at least one second support element (7) keep the continuous web (4) under tension when the welding unit (3) is in the operating position; The first support element (6) and the second support element (7) associated with each corresponding welding unit (3) are supported by a load-bearing structure (8) connected to the plurality of welding units (3) so as to correspond to the movement of the first support element (6) and the second support element (7) towards and away from the rotation axis (2a) of the rotating means (2) due to the radial movement of the plurality of welding units (3); At least one first support element (6) and at least one second support element (7) associated with each corresponding welding unit (3) are arranged in pairs between two welding units (3), and the continuous web (4) wound around the first support element (6) and the second support element (7) defines a polygonal outer perimeter with a variable length according to the positions of the first support element (6) and the second support element (7) with respect to the rotation axis (2a) of the rotating means (2). A rotating device.

2. The load-bearing structure (8) comprises a mounting body (9) for at least one pair of each at least one support element (6) and at least one second support element (7), and a connection body (10) for connecting each of the load-bearing structures (8) to a corresponding welding unit (3), the apparatus according to claim 1.

3. The mounting body (9) is movably coupled to corresponding respective connection bodies (10) different from each other, and each mounting body (9) is movable towards and away from the corresponding connection body (10), the apparatus according to claim 2.

4. Each mounting body (9) includes a first element (11) and a second element (12), and the first element (11) and the second element (12) are connected to corresponding respective connection bodies (10), the apparatus according to claim 2 or 3.

5. Each first element (11) and each second element (12) of the mounting body (9) comprise a first portion (13) slidably connected to a corresponding connection body (10) of the load-bearing structure (8) along a radial direction with respect to the rotation axis (2a) of the rotation means (2), the apparatus according to claim 4.

6. Each first element (11) and each second element (12) of the mounting body (9) comprise a second portion (14) slidably connected to the first portion (13) along a circumferential direction with respect to the rotation axis (2a) of the rotation means (2), and the first support element (6) and the second support element (7) are supported by the second portions (14) of the first element (11) and the second element (12) of the mounting body (9), the apparatus according to claim 5.

7. Each mounting body (9) supports a respective housing member (15) for accommodating a corresponding first support element (6) and a second support element (7), and the first support element (6) and the second support element (7) supported by the same housing member (15) are associated with corresponding respective welding units (3) different from each other, the apparatus according to any one of claims 2 to 6.

8. The first support element (6) and the second support element (7) are arranged at a certain distance on the corresponding housing member (15), and are arranged at the first end (15a) and the second end (15b) of the housing member (15). The device according to claim 7.

9. The device according to claim 7 or 8, wherein each housing member (15) is movably coupled to the corresponding mounting body (9) of the load-bearing structure (8).

10. The device according to claim 9 when dependent on claim 6, wherein each housing member (15) is movably coupled to the second part (14) of the first element (11) and the second element (12).

11. The device according to any one of claims 1 to 10, wherein the load-bearing structure (8) is slidably coupled to a mounting frame (16) connected to the rotating means (2).

12. The device according to any one of claims 1 to 11, wherein the first support element (6) and the second support element (7) are in the form of rollers (23), each rotating about its respective rotation axis (23a).

13. The holding means (17) holds the portion of the continuous web (4) not intended to be welded. The holding means (17) extends around the rotation axis (2a) of the rotating means (2) and has a first flexible element (18) and a second flexible element (19) with the portion of the continuous web (4) disposed therebetween. The device according to any one of claims 1 to 12.

14. A rotating method for welding a continuous web, wherein a plurality of welding units (3) for welding the continuous web (4) are arranged around a common rotation axis (2a) so as to be angularly spaced from each other. The rotating method includes the step of conveying the continuous web (4) around the rotation axis (2a) and the step of welding the continuous web (4) during the step of conveying the continuous web (4). Depending on the resulting welding interval, the rotation method includes a step of changing the welding interval, which step includes a step of changing the radial position of the plurality of welding units (3), and a step of changing the position of the continuous web (4) towards or away from the rotation axis (2a), and the step of changing the position of the plurality of welding units (2a) is executed simultaneously with the step of changing the position of the continuous web (4). The rotation method, wherein the step of changing the position of the continuous web (4) includes arranging the continuous web (4) around the rotation axis (2a) so as to define an outer periphery of a polygon having a variable length according to the radial position of the continuous web (4) with respect to the rotation axis (2a) in order to adapt to the change in the radial position of the plurality of welding units (3). Claim 15 A machine for manufacturing an article or for manufacturing a pack or pouch for containing a liquid or solid product, the machine comprising a rotating device for welding a continuous web according to any one of claims 1 to 13. Claim 16 The machine according to claim 15, wherein the article is an absorbent article.

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