Rotating device for welding continuous webs

Abstract

To allow a radial position of a rotary element of a continuous web rotary welding device to define a welding interval, and to provide a rotary welding device for a continuous web capable of changing the radial position of a welding unit to a rotating shaft so as to acquire a desired welding step along an operation outer circumference.SOLUTION: A rotary welding device includes an element (5) for rotating around a rotating shaft (5a), one or more elements (9) for supporting continuous webs (2) supported by the rotary element (5), and a plurality of units (6) for welding the continuous webs (2) supported by the rotary element (5). The rotary welding device includes first movement means configured so as to instruct a relative rotation of an anvil element to a welding tip, and second movement means configured so as to move the anvil element to the welding tip, and is configured so as to change a relative position of the welding tip to the rotating shaft (5a) of the rotary element (5).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rotary welding apparatus for a continuous web.

[0002] In particular, the device according to the invention is configured to weld the web along a direction transverse to the web feed direction according to a predefined weld spacing. [Background technology]

[0003] As is known, rotary welding devices use a rotating element that supports a number of welding units configured to weld a continuous web during rotation of the rotating element about its own axis of rotation.

[0004] The radial positions of these welding units relative to the axis of rotation of the rotating element define predefined operating circumferences of the welding units and define respective weld spacings.

[0005] To change the welding step of the apparatus, it is necessary to determine the operating perimeter and change the radial position of the welding unit relative to the axis of rotation of the rotating element to obtain the desired welding step along the operating perimeter. Summary of the Invention

[0006] In this connection, a need has been felt to manufacture a rotary device for welding a continuous web, comprising an element rotating about its own axis of rotation in order to be able to vary the steps for welding the continuous web, one or more elements for supporting the continuous web supported by the rotating element, and a plurality of units for welding the continuous web supported by the rotating element.

[0007] Each welding unit is configured to transition from a non-operating position to an operative position and from the operative position to the non-operating position.

[0008] Each welding unit includes a welding tip and an anvil element movable relative to the welding tip.

[0009] Each welding unit includes a first moving means configured to rotationally drive the anvil element relative to the welding tip from an initial position where the anvil element is angularly spaced from the welding tip to a final position and from the final position to the initial position.

[0010] In the final position, the surface (7a) of the welding tip (7) and the surface (8a) of the anvil element (8) are parallel to each other and the axis (7b) perpendicular to said surface (7a) of the welding tip and the axis (8b) perpendicular to the surface (8a) of the anvil element (8) are aligned along the same alignment axis (V).

[0011] Each welding unit includes a second moving means for moving the anvil element relative to the weld tip from a start position to an arrival position and from the arrival position to the start position, where in the start position the surfaces of the weld tip and the anvil element are parallel and aligned with each other along the same alignment axis, and in the arrival position the surfaces of the anvil element and the weld tip contact a portion of the continuous web in the area disposed therebetween.

[0012] The first drive means drives the first moving means to move the anvil element from the initial position to the final position or from the final position to the initial position.

[0013] The second drive means drives the second moving means to effect transition from the start position to the arrival position or from the arrival position to the start position.

[0014] The first drive means and the second drive means are configured to vary the relative position of the weld tip with respect to the axis of rotation of the rotating element.

[0015] Advantageously, the first and second drive means make it possible to determine the working circumference of the respective welding unit according to the required welding spacing. [Brief description of the drawings]

[0016] Further features of the present invention and its advantages will become more apparent in the following non-limiting description of preferred but non-exclusive embodiments of a rotary welding apparatus for a continuous web, as illustrated in the accompanying drawings. [Figure 1] 1 is a schematic front view of a rotary welding apparatus for absorbent articles according to the present invention; [Diagram 2] 2 is a schematic plan view of a continuous web processed by the apparatus of FIG. 1; [Diagram 3] FIG. 2 is a schematic side view of the welding unit of FIG. 1 in a non-operating position. [Figure 4] FIG. 2 is a schematic side view of the welding unit of FIG. 1 in an operating position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The numeral 1 in this specification denotes a rotary welding apparatus for continuous webs.

[0018] The device 1 according to this specification is configured for welding a continuous web 2 according to a welding spacing P.

[0019] The continuous web 2 has at least two overlapped edges intended to be welded by the device 1 according to the welding spacing P.

[0020] The continuous web 2 has a main longitudinal development L.

[0021] The apparatus 1 is configured to weld a continuous web 2 along a direction T transverse to the longitudinal development direction L.

[0022] More specifically, and with reference to FIG. 2, the apparatus 1 performs a plurality of welds along a transverse direction T of the continuous web 2 in respective weld areas 4 according to weld spacing P.

[0023] For example, the continuous web 2 is a continuous strip of absorbent articles, in particular a continuous web of pant diapers, so-called "training pants".

[0024] The continuous strip is a continuous absorbent article that is folded along the centerline of the absorbent pad.

[0025] For example, an apparatus according to the present invention is configured to weld a continuous web of absorbent article or diaper to weld the side gathers of elasticated diaper pants around the waist of a user.

[0026] According to a further example, the continuous web 2 is a continuous strip of pouches containing a liquid, in particular a liquid food product, such as a beverage, or a solid food product, such as an injection substance.

[0027] Downstream of the device 1, cutting means (not shown) act on each welded area 4 of the continuous web 2, in particular on its respective centre line, in order to separate the same into individual lengths 3.

[0028] The rotary welding device 1 comprises a rotating part 5 which rotates about its rotation axis 5a.

[0029] The axis of rotation 5a of the rotating part 5 is preferably a horizontal axis.

[0030] Alternatively, the axis of rotation 5a of the rotating part 5 is a vertical axis.

[0031] The apparatus 1 comprises a number of welding units 6 for welding a continuous web 2 .

[0032] These welding units 6 are attached to the rotating part 5 and therefore rotate about the axis of rotation 5a of the rotating part 5.

[0033] The welding units 6 are arranged at equal angular intervals from one another around the rotation axis 5 a of the rotating part 5 .

[0034] The circumferential spacing of these welding units 6 determines the weld spacing “P” of the welded area 4 of the continuous web 2 .

[0035] The diameter defined by the spacing of the welding units 6 around the rotation axis 5a of the rotating part 5 is therefore a varying parameter.

[0036] Each welding unit 6 comprises a welding tip 7 and a counter element 8 for the welding tip 7 , i.e. anvil element 8 .

[0037] The anvil element 8 of each welding unit 6 has a contact surface 8 a for a portion of the continuous web 2 .

[0038] The contact surface 8a of the anvil element 8 has an axis 8b perpendicular to the surface 8a.

[0039] The contact surface 8a has a predefined weld pattern.

[0040] The welding tip 7 of each welding unit 6 has a contact surface 7 a for a portion of the continuous strip 2 .

[0041] The contact surface 7a of the weld tip 7 has an axis 7b perpendicular to the surface 7a.

[0042] Preferably, the welding tip is an ultrasonic welding tip 7 .

[0043] Alternatively, the welding tip 7 is a thermo-mechanical tip.

[0044] Preferably, each welding tip 7 of the welding unit 6 is arranged towards the inside of the rotating part 5 and the corresponding anvil element 8 is arranged towards the outside.

[0045] In this way the relative overall dimensions are optimized making the solution more compact and therefore more preferred.

[0046] Each welding unit is configured to transition from a non-operating position to an operative position and from the operative position to the non-operating position.

[0047] In the non-operative position, a surface 8a of the anvil element 8 is relatively spaced from a surface 7a of the welding tip 7 that contacts the portion of the continuous web 2 (see FIG. 3).

[0048] In the non-operating position, an axis 7b perpendicular to the surface 7a of the welding tip is incident on an axis 8b perpendicular to the surface 8a of the anvil element 8.

[0049] In the operating position of the welding unit 6 , the surface 8 a of the anvil element 8 and the surface 7 a of the welding tip 7 are disposed between them and are in contact with the portion of the continuous web 2 which is intended to become the welding area 4 .

[0050] In the operating position, an axis 7b perpendicular to the surface 7a of the welding tip and an axis 8b perpendicular to the surface 8a of the anvil element 8 are aligned along the same alignment axis V.

[0051] The apparatus 1 comprises a number of support elements 9 for supporting a continuous web 2 .

[0052] These support elements 9 for supporting the continuous strip 2 are attached to the rotating part 5 and therefore rotate about the axis of rotation 5a of the rotating part 5 (see FIG. 3).

[0053] The welding units 6 and the supporting elements 9 are mounted one on top of the other.

[0054] In other words, each welding unit 6 is disposed between a corresponding respective pair of support elements 9 .

[0055] Each support element 9 has a holding surface 12 for holding the continuous web 2 .

[0056] The support surface 12 of each support element 9 is preferably curved.

[0057] Alternatively, the support surface 12 of each support element 9 is preferably a flat surface.

[0058] Preferably, these support elements 9 are configured to hold the continuous web 2 by suction.

[0059] In this regard, the support surface 12 is provided with a pattern of suction holes.

[0060] The apparatus 1 comprises a station 10 for feeding a continuous web 2 to be welded and an outfeed station 11 for the welded continuous web 2 .

[0061] The continuous web 2 is fed through the feed station 10 by a roller 13, preferably a suction roller, rotating about its axis of rotation 13a, so that it wraps around the holding surface 12 of the support element 9 without slipping.

[0062] It should be noted that when the continuous web 2 is a continuous strip of absorbent articles, the continuous web 2 is wrapped around the support element 9 of the apparatus 1 so that a continuous series of overlapping elastic gathers faces towards the front of the apparatus where it is accessible to the operator.

[0063] The welded continuous web 2 is fed through an outfeed station 11 by a roller 14, preferably a suction roller, rotating about its axis of rotation 14a.

[0064] A rotation axis 13a of the supply roller 13 for the continuous web 2 and a rotation axis 14a of the transport roller 14 for the continuous web 2 which is welded to the supply roller 13 are parallel to each other.

[0065] The axis of rotation 5 a of the rotating element 5 is parallel to the axes of rotation 13 a , 14 a of the feed roller 13 of the continuous web 2 and of the transport roller 14 of the welded continuous web 2 .

[0066] According to the invention, each welding unit 6 comprises first moving means 15 for moving the anvil element 8 relative to the welding tip 7 by imparting a movement of the anvil element 8 towards the welding tip 7 and a movement of the anvil element 8 away from the welding tip 7.

[0067] The movement consists in positioning the anvil element 8 in a position in which the anvil element 8 is aligned with the welding tip 7, i.e. in a mutual position in which the contact surface 8a of the anvil element 8 is parallel to the contact surface 7a of the welding tip 7 and the axis 8b perpendicular to the contact surface 8a of the anvil element 8 is aligned with the axis 7b perpendicular to the contact surface 7a of the welding tip 7 along the same alignment axis V.

[0068] The first moving means 15 is configured to rotationally drive the anvil element 8 relative to the welding tip 7 from an initial position in which the anvil element 8 is angularly spaced from the welding tip 7 to a final position in which the surfaces 7a of the welding tip 7 and the anvil element 8 are parallel and aligned with each other along the same alignment axis V, and from the final position to the initial position.

[0069] In the initial position, the direction of the axis 8b perpendicular to the surface 8a of the anvil element 8 is incident on the direction of the axis 7b perpendicular to the surface 7a of the welding tip 7 so as to form a particularly acute angle.

[0070] The first movement means 15 comprises at least one articulation system 30 which comprises at least one control crank 19 and a lever 21, the lever 21 being moved by the crank 19 which oscillates about its oscillation axis 21a.

[0071] Oscillation of lever 21 about oscillation axis 21a causes anvil element 8 to move towards and away from welding tip 7, i.e., transitions anvil element 8 from an initial position to a final position relative to welding tip 7, or from the final position to the initial position.

[0072] The first moving means 15 comprises at least a first connecting rod 20 connected to the crank 19 and a second connecting rod 22 connected to the first connecting rod 20 and to a lever 21 .

[0073] A first connecting rod (20) and a second connecting rod (22) transmit the controlled movement from the crank (19) to the lever (21).

[0074] In particular, the second connecting rod 22 is connected to the lever 21 in a central position with respect to the main longitudinal development of the lever 21 .

[0075] The first connecting rod 20 is rotatably connected to the crank 19 by a pin 38 .

[0076] The pin 38 connecting the first connecting rod 20 to the crank 19 is integral with the crank 19 .

[0077] The second connecting rod 22 is connected in a rotatable manner to a corresponding part of the lever 21 by means of a pin 39 which is integral with the lever 21 .

[0078] The first connecting rod 20 is rotatably connected to the second connecting rod 22 by a pin 40 .

[0079] The crank 19, the first connecting rod 20, the second connecting rod 22 and the lever 21 of the first moving means 15 define an articulated "toggle" system.

[0080] The first movement means 15 comprises a pair of articulation systems 30 arranged opposite each other.

[0081] According to an alternative embodiment, for each welding unit 6 the first movement means 15 comprise a synchronously driven double articulated "toggle" system.

[0082] Counterclockwise rotation of the crank 19 causes relative movement of the first connecting rod 20 and the second connecting rod 22, which causes the lever 21 to oscillate clockwise about the oscillation axis 21a, so that the anvil element 8 moves from an initial position to a final position or from the final position to the initial position relative to the welding tip 7.

[0083] With reference to the illustrated embodiment, counterclockwise rotation of the crank 19 causes counterclockwise oscillation of the lever 21 about the oscillation axis 21a, which results in the anvil element 8 moving away from the welding tip 7, i.e., transitioning from the final position to the initial position.

[0084] In the final position of the anvil element 8 relative to the welding tip 7 , at least the first connecting rod 20 and the second connecting rod 22 are aligned with each other in an inclined position relative to the position of the lever 21 .

[0085] In particular, in the mutual alignment position, at least the first connecting rod 20 and the second connecting rod 22 are arranged along a direction perpendicular to the position of the lever 21 .

[0086] In this position of mutual alignment, the connecting pins 38, 39, 40 from the crank 19 to the lever 21 are arranged parallel to one another.

[0087] The first driving means 17 controls the movement of the first moving means 15 .

[0088] The configuration assumed by the crank 19, the first connecting rod 20, the second connecting rod 22 and the lever 21 in the final position of the anvil element 8 relative to the welding tip 7 is such that no welding forces are transmitted to the first drive means 17, since the forces are de-multiplied by the configuration assumed by the articulation system 30 of the first moving means 15.

[0089] The first drive means 17 controls the movement of the crank 19 of the articulation system 30 of the first movement means 15 .

[0090] The first drive means 17 is configured to be movable in a radial direction relative to the rotation axis 5 a of the rotation element 5 .

[0091] Advantageously, the radial movement of the first drive means 17 makes it possible to modify the operating circumference of each welding unit 6 without modifying the elements of the articulation system 30 of the first moving means 15, thus maintaining its motion transmission ratio.

[0092] Each welding unit 6 comprises second moving means 16 for moving the anvil element 8 relative to the welding tip 7 from a start position in which the contact surface 8a of the anvil element 8 and the contact surface 7a of the welding tip 7 are parallel and aligned with each other along the same alignment axis V, to a arrival position in which the contact surface 8a of the anvil element 8 and the contact surface 7a of the welding tip 7 contact the continuous web 2 arranged therebetween.

[0093] The arrival position corresponds to the operating position of the welding unit 6 .

[0094] From the start position to the arrival position, the anvil element 8 translates towards the corresponding welding tip 7 until it comes into contact with the continuous web 2 disposed between the anvil element 8 and the corresponding welding tip 7 .

[0095] Conversely, the second moving means 16 is configured to translate the anvil element 8 away from the welding tip 7 and thus release the continuous web 2 disposed therebetween.

[0096] The second moving means 16 is driven by a second driving means 18 .

[0097] The second movement means 16 comprises at least one articulation system 33 comprising a crank 34 for controlling a connecting rod 35 rotatably connected to the oscillating axis 21 a of the lever 21 .

[0098] The crank 34 and the connecting rod 35 are rotatably connected by a pin 41 .

[0099] The pin 41 is connected to the crank 34 .

[0100] The crank 34 , connecting rod 35 and lever 21 define an articulated “toggle” system 33 .

[0101] According to an alternative embodiment, for each welding unit 6 the second movement means 16 comprise a synchronously driven double articulated "toggle" system.

[0102] In the arrival position, the connecting rod 35 is arranged along a direction perpendicular to the crank 34 .

[0103] In the arrival position, the connecting rod 35 is arranged along a direction perpendicular to the lever 21 .

[0104] The second movement means 16 comprises a pair of articulation systems 33 arranged opposite each other.

[0105] The second moving means 16 comprises a pneumatic system 37 configured to determine the translation towards or away from the anvil element 8 and vice versa relative to the welding tip 7 by means of the articulation system 33 described above.

[0106] The pneumatic system 37 makes it possible to apply and maintain a predefined pressure between the anvil element 8 and the welding tip 7 so that the pressure remains as constant as possible throughout the entire welding process, i.e. as long as the welding unit 6 is in the operating position.

[0107] The region of the continuous web 2 disposed between the surface 8 a of the anvil element 8 and the surface 7 a of the welding tip 7 is welded when the welding tip 7 is actuated to form the weld region 4 .

[0108] The pneumatic system 37 is connected to the crank 34 of the second movement means 16 .

[0109] The pneumatic system 37 comprises a piston 44 , the rod 45 of which is rotatably connected to an arm 46 which is rotatably connected to the crank 34 of the second moving means 16 .

[0110] In the arrival position, the arm 46 to which the rod 45 of the piston 44 is connected is aligned with the arm 46 which is connected to the crank 34 .

[0111] This alignment advantageously allows the force generated by the pneumatic system 37 to be transferred directly to the weld tip 7 .

[0112] The lever ratio of the articulation system 33 makes it possible to multiply the force generated by the pneumatic system 37 .

[0113] Advantageously, this alignment makes it possible to isolate the forces generated by the pneumatic system from the articulation system 33 of the second movement means 16, preventing said forces from affecting the second drive means 18.

[0114] The second drive means 18 controls the movement of the crank 19 of the articulation system 30 of the first movement means 15 .

[0115] The second drive means 18 is configured to be movable in a radial direction relative to the rotation axis 5 a of the rotation element 5 .

[0116] Advantageously, the radial movement of the second drive means 18 makes it possible to vary the operating circumference of each welding unit 6 without modifying the elements of the articulation system 33 of the second moving means 16 and thus maintaining its motion transmission ratio.

[0117] The first drive means 17 and the second drive means 18 each comprise a single control member 26 , a first drive transmission unit 32 and a second drive transmission unit 24 .

[0118] The control unit 26 comprises a drum 29 which rotates about its axis of rotation and which has several slide tracks 28 for the cam follower rollers 27 on its periphery.

[0119] The first motion transmission unit 32 comprises a bar-shaped element 31 having at one end at least one cam follower roller 27 configured to engage a corresponding track 28 of the drum 29 .

[0120] The rod-shaped elements 31 extend in a radial direction relative to the rotation axis 5 a of the rotation element 5 .

[0121] The track 28 of the drum is configured to impart rotation of the bar-shaped elements 31 along at least one stretch.

[0122] The rotation of the rod-shaped element 31 causes the first moving means 15 to move.

[0123] The first drive transmission unit 32 comprises at least one rotational transmission element 43 provided on a rod-like element 31 to the crank 19 of the articulation system 30 of the first movement means 15 .

[0124] The transfer element 43 is slidably constrained to the bar element 31 for varying the radial position of the anvil element 8 .

[0125] The transfer element 43 is constrained to rotate with the rod element 31 whatever position it takes along the rod element 31 .

[0126] The crank 19 is rotatably connected to a transmission element 43 by means of a shaft 25 which rotates about its axis of rotation 25a.

[0127] The crank 19 of the double articulated system 30 is connected to a shaft 25 .

[0128] The second motion transmission unit 24 comprises a bar-shaped element 23 having at one end at least one cam follower roller 27 configured to engage a corresponding track 28 of a drum 29 .

[0129] The rod-shaped elements 23 extend in a radial direction relative to the rotation axis 5 a of the rotation element 5 .

[0130] The track 28 of the drum is configured to impart rotation of the bar-shaped elements 23 along at least one section.

[0131] The rotation of the rod-like element 23 causes the actuation of the motion transmission unit 32 for moving the second moving means 16 .

[0132] The second drive transmission unit 24 comprises at least one rotational transmission element 48 provided on a rod-like element 23 to a crank 19 of the articulation system 33 of the second movement means 16 .

[0133] The transfer element 48 is slidably constrained to the bar element 23 so as to allow the radial position of the anvil element 8 to be varied.

[0134] Whatever position the transfer element 48 takes along the rod element 23 , it is constrained to rotate with the rod element 23 .

[0135] The crank 34 is rotatably connected to a transmission element 48 by a shaft 49 which rotates about its axis of rotation 49a.

[0136] The crank 34 of the double articulated system 33 is connected to a shaft 49 .

[0137] The rotation of the rod-like element 23 causes the actuation of a motion transmission unit 24 for moving the second moving means 16 .

[0138] Advantageously, the possibility of translating the motion transmission elements 43, 48 of the first drive means 17 and the second drive means 18 along the respective rod-shaped elements 31, 23 makes it possible to change the position of the anvil element 8 relative to the rotation axis 5a of the rotating element 5.

[0139] This change in position allows the operating perimeter to be defined according to the weld spacing.

Claims

1. 1. A rotating apparatus for sealing a continuous web, comprising: A rotating element (5) that rotates about its own axis of rotation (5a); one or more elements (9) for supporting the continuous web (2) supported by said rotating element (5); a plurality of units (6) for welding the continuous web (2) supported by the rotating element (5), Each welding unit (6) is configured to transition from a non-operating position to an operating position and from said operating position to said non-operating position; Each welding unit (6) comprises a welding tip (7) and an anvil element (8) movable relative to said welding tip (7); Each welding unit (6) comprises a first moving means (15) configured to rotationally drive said anvil element (8) relative to said welding tip (7) from an initial position in which said anvil element (8) is angularly spaced from said welding tip (7) to a final position and from said final position to said initial position, in said final position, the surface (7a) of the welding tip (7) and the surface (8a) of the anvil element (8) are parallel to each other and an axis (7b) perpendicular to the surface (7a) of the welding tip (7) and an axis (8b) perpendicular to the surface (8a) of the anvil element (8) are aligned along the same alignment axis (V); each welding unit (6) comprises second moving means (16) for moving said anvil element (8) relative to said welding tip (7) from a start position, in which said surface (7a) of said welding tip (7) and said surface (8a) of said anvil element (8) are parallel and aligned along the same alignment axis (V), to a arrival position, in which said surface (8a) of said anvil element (8) and said surface (7a) of said welding tip (7) are in contact with a portion of the continuous web (2) in the area located therebetween, and from said arrival position to said start position, a first driving means (17) drives said first moving means (15) to move said anvil element (8) from said initial position to said final position or from said final position to said initial position; a second drive means (18) drives the second moving means (16) to effect a transition from the start position to the arrival position or from the arrival position to the start position; A rotating device, wherein the first driving means (17) and the second driving means (18) are configured to vary the relative position of the welding tip (7) with respect to the rotation axis (5a) of the rotating element (5).

2. 2. The device according to claim 1, wherein the first drive means (17) comprises at least one motion transmission element (43) for transmitting motion to the first moving means (15) and a rod-shaped element (31), the motion transmission element (43) being slidably constrained to the rod-shaped element (31) so as to translate along the rod-shaped element (31) and to change its relative position along the rod-shaped element (31).

3. 3. The device according to claim 2, wherein the rod-shaped element (31) of the first drive means (17) is configured to rotate, the rotation of the rod-shaped element (31) causing the actuation of the first moving means (15) via at least one motion transmission element (43).

4. 4. The apparatus according to claim 1, wherein the second drive means (18) comprises a motion transmission element (48) for transmitting motion to the second moving means (16) and a rod-shaped element (23), the motion transmission element (48) being slidably constrained to the rod-shaped element (23) so as to translate along the rod-shaped element (23) and change its relative position along the rod-shaped element (23).

5. 5. The device according to claim 4, wherein the rod-shaped element (23) of the second drive means (18) is configured to rotate, the rotation of the rod-shaped element (23) causing the actuation of the second moving means (16) via at least one motion transmission element (48).

6. 6. Apparatus according to claim 4 or 5 when dependent on claim 2 or 3, wherein cam means (26) drive the rotation of the rod-like elements (23, 31) of the first drive means (17) and the second drive means (18).

7. 7. Apparatus according to any one of claims 1 to 6, wherein the first moving means (15) comprises at least one articulation system (30) comprising a crank (19) moved by the first driving means (17) and a lever (21) moved by the crank (19) so as to oscillate about an oscillation axis (21a) for controlling the angular movement of the anvil element (8) relative to the welding tip (7) from the initial position to the final position and from the final position to the initial position.

8. 8. The device according to claim 7, wherein the first moving means (15) comprises at least a first connecting rod (20) connected to the crank (19) and a second connecting rod (22) connected to the first connecting rod and to the lever (21), the first connecting rod (20) and the second connecting rod (22) transmitting movement from the crank (19) to the lever (21).

9. 9. Apparatus according to claim 7 or 8, wherein the second movement means (16) comprises at least one articulation system (33) comprising a crank (34) moved by the second drive means (18) and a connecting rod (35) rotatably connected to the oscillation axis (21a) of the lever (21).

10. 10. Apparatus according to claim 9, wherein the second moving means (16) comprises a pneumatic system (37) configured to determine, via the articulation system (33), a translation relative to the welding tip (7) towards or away from the anvil element (8) and vice versa.

11. A rotating device as described in any of claims 1 to 10, wherein the rotating device is a rotating device for sealing a continuous web to produce absorbent articles or to produce bags for containing liquid or solid products.

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