Ultrasonic welding apparatus and method

Abstract

The present invention performs control such that ultrasonic energy is applied to a web by driving a horn via an ultrasonic wave generator in one of a forward path and return path of an anvil, and ultrasonic energy is not applied to the web in the other of the forward path and return path.

Description

[Technical Field]

[0001] The present invention relates to an ultrasonic welding apparatus and method. [Background technology]

[0002] A known device has a horn that rotates with a drum and an anvil that cooperates with the horn, and as the drum rotates, the anvil moves back and forth in the axial direction of the drum to perform welding processing on a web clamped between the horn and the anvil (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6228232 (Abstract) Summary of the Invention

[0004] In this prior art, welding is performed on both the reciprocating movements of the anvil, but there are problems such as the web shifting during the reciprocating movements of the anvil, causing misalignment between the welding marks on the outward movement and the welding marks on the return movement, resulting in unstable welding strength and a poor appearance.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an ultrasonic welding apparatus and method that can form welding marks with stable welding strength and excellent appearance.

[0006] The ultrasonic welding device of the present invention includes a conveying drum 200 that conveys a web W along an outer peripheral surface 44a while rotating; At least one horn 14 is disposed radially inside or outside the outer peripheral surface 44a of the conveying drum 200 and rotates together with the conveying drum 200; At least one anvil 15 is arranged on the other side of the outer peripheral surface 44a in the radial direction of the conveying drum 200, and rotates together with the conveying drum 200; a moving mechanism 300 that reciprocates the anvil 15 in the direction of the axis L1 of the conveying drum 200 in accordance with the rotation of the conveying drum 200, and clamps the web W between the anvil 15 and the horn 14 on the outgoing path OB and the returning path IB of the anvil 15; an ultrasonic generator 16 that vibrates the horn 14 to apply ultrasonic energy to the web W sandwiched between the anvil 15 and the horn 14; and a control device 500 that vibrates the horn 14 via the ultrasonic generator 16 to apply ultrasonic energy to the web W on either the outbound path OB or the inbound path IB, and controls so that ultrasonic energy is not applied to the web W on the other of the outbound path OB or the inbound path IB.

[0007] On the other hand, the ultrasonic welding method of the present invention includes a conveying drum 200 that conveys the web W along the outer peripheral surface 44a while rotating, At least one horn 14 is disposed radially inside or outside the outer peripheral surface 44a of the conveying drum 200 and rotates together with the conveying drum 200; An ultrasonic welding method for welding the web (W) using an ultrasonic welding device including at least one anvil (15) that is arranged on the other side of the outer peripheral surface (44a) in the radial direction of the conveying drum (200) and rotates together with the conveying drum (200), a step of transporting the web W by the transport drum 200; a step of reciprocating the anvil 15 in the direction of the axis L1 of the conveying drum 200 in accordance with the rotation of the conveying drum 200, and clamping the web W between the anvil 15 and the horn 14 on the outgoing path OB and the returning path IB of the anvil 15; a step of vibrating the horn 14 to apply ultrasonic energy to the web W sandwiched between the anvil 15 and the horn 14; The method includes a step of vibrating the horn 14 via the ultrasonic generator 16 to apply ultrasonic energy to the web W on either the outgoing path OB or the returning path IB, and controlling the horn 14 so that ultrasonic energy is not applied to the web W on the other of the outgoing path OB or the returning path IB.

[0008] According to the present invention, the web is welded only on the outward or return path, which prevents misalignment of the weld marks, unstable weld strength, and poor appearance.

[0009] In the present invention, "welding webs" may mean welding multiple overlapping webs together, or may mean welding a single web laminate folded in two, i.e., performing a so-called side seal. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a process diagram for explaining an outline of the method for producing a disposable diaper according to the present invention. [Figure 2] FIG. 2 is a front view of the main part of the ultrasonic welding device according to the present invention. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of a part of FIG. [Figure 5] FIG. 5 is a front view showing the horn holding mechanism of FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a schematic diagram showing the relationship between the rotational position and the linear position of the anvil. [Figure 9] FIG. 9 is a schematic perspective view showing the linear movement of the anvil in the forward path. [Figure 10] FIG. 10 is a schematic perspective view showing the linear movement of the anvil in the return path. DETAILED DESCRIPTION OF THE INVENTION

[0011] In the present invention, preferably, when ultrasonic energy is not applied to the web W, the control device 500 is configured to control the ultrasonic generator 16 so as not to vibrate the horn 14.

[0012] In this case, it is possible to suppress the generation of unnecessary vibrations to the web W during transport.

[0013] In the present invention, the moving mechanism 300 is preferably configured so that the anvil 15 moves back and forth so that the average moving speed of the anvil 15 on one of the outgoing path OB or the returning path IB, where the ultrasonic energy is applied, is smaller than that on the other path.

[0014] In this case, the slow movement speed of the anvil on one side allows for sufficient welding of the web, and the fast movement speed of the anvil on the other side does not increase the time required for the anvil to move back and forth in the welding process.

[0015] In the present invention, the movement mechanism 300 is preferably configured so that the anvil 15 overruns the welding region α where the web W is to be welded.

[0016] In this case, ultrasonic welding can be performed on the web over the entire area in the direction crossing the web transport direction.

[0017] In the present invention, preferably, the control device 500 controls the ultrasonic generator 16 so as not to vibrate the horn 14 in the overrun region β.

[0018] In this case, damage caused by contact between the anvil and the horn can be prevented.

[0019] The features described and / or illustrated in connection with one of the above embodiments or examples below may be used in the same or similar manner in one or more other embodiments or examples, and / or in combination with or in place of features of the other embodiments or examples.

[0020] The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and explanation, and should not be used to define the scope of the present invention. The scope of the present invention is defined only by the claims. In the accompanying drawings, the same part numbers in multiple drawings indicate the same or corresponding parts. [Example]

[0021] Before describing the apparatus according to the embodiment of the present invention, the structure and manufacturing method of a disposable diaper 70, which is an example of a diaper manufactured by the apparatus, will be described below.

[0022] Referring to FIG. 1, the disposable diaper 70 has a front portion 70a that is placed on the wearer's abdomen when worn, a rear portion 70b that is placed on the wearer's buttocks, and a crotch portion 70c that extends from the front portion 70a between the wearer's legs to the rear portion 70b.

[0023] Both side edges of the front abdominal portion 70a and both side edges of the rear dorsal portion 70b are welded to each other at two welded portions S so that the front abdominal portion 70a and the rear dorsal portion 70b are connected in an annular shape.

[0024] A method for manufacturing the disposable diaper 70 will now be outlined.

[0025] <Transportation process P1> In the transport step P1, the web W extending in a specific direction is transported along its longitudinal direction. In the following description, the flow direction of the web W is defined as the horizontal direction, and the direction perpendicular to the horizontal direction in FIG. 1 is defined as the vertical direction.

[0026] The web W has an inner web that faces the wearer's body surface when worn, an outer web that faces the wearer's outside when worn, and an elastic member sandwiched between the inner and outer webs. The inner and outer webs and the elastic member are not shown in the figures.

[0027] <Leg hole forming process P2> In the leg hole forming step P2, a leg hole L is formed in the center of the web W in the longitudinal direction.

[0028] The region of the web W between the two leg holes L corresponds to the crotch portion 70c. The two longitudinal positions of the region of the web W that corresponds to the crotch portion 70c correspond to the front abdominal portion 70a and the back portion 70b, respectively.

[0029] <Absorbent body bonding process P3> In the absorbent body joining step P3, the absorbent body Ab is joined to the web W at a position between the two leg holes L.

[0030] The absorbent body Ab includes a liquid-permeable sheet, a water-repellent sheet that is water-repellent and breathable, and an absorbent core sandwiched between the liquid-permeable sheet and the water-repellent sheet (the liquid-permeable sheet, water-repellent sheet, and absorbent core are not shown in the figures).

[0031] Although the method of joining the absorbent body Ab onto the web W has been described, it is also possible to join the absorbent core by sandwiching it between the inner web and the outer web of the web W. In this case, the inner web is made of a liquid-permeable sheet, and the outer web is made of a water-repellent and breathable sheet.

[0032] <Folding process P4> In the folding step P4, the web W on which the absorbent body Ab is placed is folded in half in the longitudinal direction, whereby the portion of the web W corresponding to the front abdominal portion 70a and the portion corresponding to the rear portion 70b are overlapped with each other.

[0033] <Welding process P5> In the welding process P5, the portions corresponding to the side edges of the front abdominal portion 70a and the portions corresponding to the side edges of the rear portion 70b between two adjacent absorbents Ab in the folded web W (object to be welded) are ultrasonically welded to each other.

[0034] Specifically, in the welding step P5, the web W is ultrasonically welded in an area including the position to be cut in the cutting step P6, which will be described later. This provides a side seal that forms a loop around the waist portion of the worn article, thereby forming the diaper into a pants-type diaper.

[0035] The welded portions S are formed in vertical welded ranges D1 in the portions corresponding to the side edges of the front abdominal portion 70a and the portions corresponding to the side edges of the back portion 70b.

[0036] <Cutting process P6> In the cutting step P6, the web W is cut along cutting lines extending in the vertical direction at the center of the welded portion S formed in the welding step P5. As a result, the web W (continuous body) is cut into individual disposable diapers 70.

[0037] Next, an overview of the ultrasonic welding device 1 according to the present invention will be described.

[0038] As shown in FIG. 2, the ultrasonic welding device 1 includes a conveying drum 200 that conveys the web W in the circumferential direction along an outer peripheral surface 44a while rotating. The peripheral speed of the transport drum 200 and the transport speed of the web W are set to be the same so that the web W does not slip on the outer peripheral surface 44a.

[0039] The transport drum 200 includes a horn 14 that is disposed radially inward of the transport drum 200 relative to the outer circumferential surface 44 a and rotates together with the transport drum 200 . The transport drum 200 also includes an anvil 15 that is disposed radially outward of the transport drum 200 relative to the outer circumferential surface 44 a and rotates together with the transport drum 200 . In this example, ten horns 14 and ten anvils 15 are provided.

[0040] The movement mechanism 300 of FIG. 4 moves the anvil 15 back and forth in the direction of the axis L1 of the transport drum 200 as the transport drum 200 rotates. As will be described later, the web W (FIG. 2) is clamped between the anvil 15 and the horn 14 during the forward and backward movements of the anvil 15. It should be noted that the web W is omitted from the illustrations of FIGS.

[0041] 2 is provided for each horn 14, and vibrates the horn 14 to apply ultrasonic energy to the web W sandwiched between the anvil 15 and the horn 14. The horn 14 vibrates, for example, in a direction intersecting the plane of the web W.

[0042] The control device 500 of Figure 3 vibrates the horn 14 via the ultrasonic generator 16 to apply ultrasonic energy to the web W on either the outbound path or the return path, and controls so as not to apply ultrasonic energy to the web W on the other of the outbound path OB or the return path IB. The control device 500 of this example controls the ultrasonic generator 16 so as to apply ultrasonic energy to the web W on the outgoing path OB and not to apply ultrasonic energy to the web W on the returning path IB. In this specification, "no ultrasonic energy is applied" also includes the case where the horn vibrates to an extent that does not result in welding of the web.

[0043] Next, the ultrasonic welding apparatus 1 that performs the welding step P5 will be described in detail with reference to FIG.

[0044] The ultrasonic welding device 1 ultrasonically welds the web W that has been folded in half in the folding process P4 and introduced via the introduction roller F1, and sends the welded web W to the cutting process P6 via the discharge roller F2.

[0045] Specifically, as shown in Figure 3, the ultrasonic welding device 1 includes a drive shaft support member 2 erected on a predetermined work surface, a cam drum (drive mechanism) 3 fixed to the drive shaft support member 2, a cam follower (drive mechanism) 23 provided in the cam groove 3a of the cam drum 3, a drive shaft 4 supported rotatably relative to the drive shaft support member 2 around the axis L1, a rotating drum 5 fixed to the drive shaft 4, ten welding units 6 fixed to the rotating drum 5, ten power transmission mechanisms 7 (only two are shown in Figure 3) for transmitting power from the cam drum 3 and the cam follower 23 to the welding units 6, a slip ring (rotary connector) 8 and a rotary joint 9 provided at the base end of the drive shaft 4, an electric wire guide member 11 and a pipe connection member 12 provided at the tip end of the drive shaft 4, and a motor 10 for rotating the drive shaft 4.

[0046] In FIG. 3, the direction parallel to the axis L1 of the drive shaft 4 is defined as the X direction, the vertical direction in FIG. 3 is defined as the Z direction, and the direction perpendicular to the XZ plane is defined as the Y direction.

[0047] 3 and 4, the drive shaft support member 2 supports the components (excluding the drive shaft support member 2) of the ultrasonic welding device 1 on a work surface. Specifically, the drive shaft support member 2 is a plate-like member having a through hole 2a formed therein that penetrates in the X direction.

[0048] The cam drum 3 is fixed to the drive shaft support member 2 with one end of the cam drum 3 in the X direction fitted into the through hole 2a of the drive shaft support member 2. In this state, the axis of the cam drum 3 coincides with the axis L1.

[0049] A cam groove 3a is formed on the outer peripheral surface of the cam drum 3. Although details will be described later, the cam groove 3a has a shape that allows the cam follower 23, which rotates about the axis L1, to move in the X direction. The cam drum 3 and the cam follower 23 correspond to a drive mechanism that drives the anvil 15 so that the anvil 15 moves relative to the horn 14, which will be described later.

[0050] As shown in Fig. 3, the drive shaft 4 is driven to rotate by the motor 10. Specifically, a belt V1 is stretched between a pulley 4a provided midway along the drive shaft 4 and a pulley 10a provided on the output shaft of the motor 10. As the output shaft of the motor 10 rotates, power from the motor 10 is transmitted to the drive shaft 4 via the belt V1. The motor 10 is fixed to the drive shaft support member 2 via a bracket (not shown).

[0051] The drive shaft 4 passes through the cam drum 3 in the X direction while being rotatable relative to the cam drum 3. In other words, the drive shaft 4 is indirectly supported by the drive shaft support member 2 via the cam drum 3. The base end of the drive shaft 4 is located on the opposite side of the drive shaft support member 2 from the cam drum 3, and the tip end of the drive shaft 4 is located on the opposite side of the cam drum 3 from the drive shaft support member 2.

[0052] The rotating drum 5 includes a disk 5a fixed to the tip of the drive shaft 4, a covering wall 5b extending in the X direction from the periphery of the disk 5a and covering the outer peripheral surface of the cam drum 3, and an adjusting plate 5c detachably attached to the side of the disk 5a opposite the covering wall 5b. The disk 5a and the adjusting plate 5c correspond to a rotating body that can rotate around an axis L1.

[0053] The adjustment plate 5c is formed with a screw hole 5e (see FIG. 4) for attaching the welding unit 6.

[0054] 4 to 7, the welding unit 6 including the horn 14 and the anvil 15 will be described below. Note that since the ten welding units 6 have the same configuration, only the configuration of one welding unit 6 shown in FIGS. 4 to 7 will be described.

[0055] The welding unit 6 includes a horn (second welding device) 14 and an anvil (first welding device) 15 that weld the web W by clamping the web W, an ultrasonic generator 16 connected to the horn 14, a cooling jacket 17 (cooler) that cools the ultrasonic generator 16, an attachment portion 18 that allows the welding unit 6 to be attached to the rotating drum 5 (adjustment plate 5c), a base 19 that is connected to the end of the attachment portion 18 and extends in the X direction, a horn holding mechanism 20 that is provided at the tip of the base 19 and holds the horn 14, and an anvil holding mechanism 21 that is provided at the base end of the base 19 and holds the anvil 15.

[0056] 2 and 3, the mounting portion 18 allows the welding unit 6 to be mounted on the rotating drum 5 with the horn holding mechanism 20 arranged on the same circumference centered on the axis L1. Furthermore, the mounting portion 18 can be mounted on the rotating drum 5 (adjustment plate 5c) so that the mounting position of the welding unit 6 with respect to the rotating drum 5 can be adjusted in the radial direction centered on the axis L1 (the Z direction in FIGS. 4 to 6).

[0057] 4 and 5, horn holding mechanism 20 holds horn 14 in a state in which horn 14 is open facing radially outward.

[0058] Specifically, the horn holding mechanism 20 comprises a covering member 42 that covers the horn 14 from one radial side (the lower side in Figures 4 and 5) and both sides in the Y direction, a horn support member 43 that supports the horn 14 inside the covering member 42, and a pair of web support members (welded portion support members) 44 fixed to the covering member 42.

[0059] The covering member 42 includes a bottom plate 42a and a pair of side plates 42b erected on both ends of the bottom plate 42a in the Y direction. An insertion hole 42c penetrating the bottom plate 42a in the Z direction is formed in the bottom plate 42a. The ultrasonic generator 16, which is disposed radially inside the covering member 42, is connected to the horn 14 through the insertion hole 42c.

[0060] Horn support member 43 is fixed to covering member 42 and supports the middle portion of horn 14 (the portion corresponding to the node of the vibration from ultrasonic generator 16). The width dimension of horn 14 in the X direction corresponds to the width of welding range D1 of welding portion S formed on web W (see FIG. 1).

[0061] Each web support member 44 is attached to the end face of each side plate 42b so as to extend on both sides of the tip of the horn 14 in the circumferential direction centered on the axis L1. Specifically, each web support member 44 has a support portion 44a (outer peripheral surface 44a) extending in the circumferential direction from the horn 14 and a bent portion 44b bent from the end in the circumferential direction. The disk 5a, adjustment plate 5c, mounting portion 18, and web support member 44 of the rotating drum 5 correspond to a rotary support mechanism that is rotatable about the axis L1 and can support the continuously supplied web W on the circumference centered on the axis L1.

[0062] The radial outer peripheral surface 44a of the web support member 44 functions as a support surface for supporting the web W. Specifically, the width dimension in the X direction of the outer peripheral surface 44a corresponds to the width dimension D2 (see FIG. 1) between the waist side end and the crotch side end of the web W.

[0063] As shown in FIG. 5, bent portion 44b is bent from support portion 44a so as to be positioned closer to axis L1 (FIG. 4) than straight line L2 connecting the tips of adjacent support portions 44a between two horns 14.

[0064] This allows the portion of the web W (see FIG. 1) including the welded portion S to be supported by the support portion 44a and the tip of the horn 14, and also allows the portion of the web W including the absorber Ab, which is thicker than the welded portion S, to be disposed between adjacent bent portions 44b. Therefore, unlike when the web W is supported on the same plane, it is possible to prevent portions of the web W other than the absorber Ab from floating up due to the thickness of the absorber Ab.

[0065] 4 to 7, anvil holding mechanism 21 holds anvil 15 so as to be movable in the X direction relative to horn holding mechanism 20 (horn 14).

[0066] As shown in Figures 6 and 7, specifically, the anvil holding mechanism 21 includes a pair of rail holding plates 45 that are erected on the base 19 and face each other in the Y direction, a pair of rails 46 that are respectively held by the rail holding plates 45, a pair of sliders 47 that respectively engage with the rails 46 so as to be movable in the X direction, a main body 48 to which both sliders 47 are fixed, three rotating shafts 49 to 51 that are provided on the main body 48, four timing pulleys 52 to 55 that can rotate around the rotating shafts 49 to 51, timing belts V2 and V3 that are stretched over the timing pulleys 52 to 55, and a connecting member (see Figure 4) 59 that connects the timing belt V2 to the rail holding plates 45.

[0067] The main body 48 is attached to the rail holding plate 45 (base 19) in a state in which it can move in the X direction by the engagement between the rail 46 and the slider 47.

[0068] 7, the rotating shafts 49 to 51 each extend in the Y direction, are aligned in the X direction, and are rotatable relative to the main body 48 about an axis parallel to the Y direction. A timing pulley 52 is provided at one end of the rotating shaft 49. A timing pulley 53 is provided at the end of the rotating shaft 50 on the same side as the timing pulley 52, and a timing pulley 54 is provided at the end of the rotating shaft 50 opposite the timing pulley 53. A timing pulley 55 is provided at the end of the rotating shaft 51 on the same side as the timing pulley 54, and an anvil 15 is provided at the end of the rotating shaft 51 opposite the timing pulley 55.

[0069] The timing belt V2 is wound around a timing pulley 52 and a timing pulley 53. The timing belt V3 is wound around a timing pulley 54 and a timing pulley 55. The connecting member 59 connects the rail holding plate 45 to a part of the timing belt V2 located on the axis L1 side of the timing pulleys 52 and 53.

[0070] When the main body 48 moves in the X direction relative to the rail holding plate 45 (base 19), a force that moves the timing belt V2 in the X direction is transmitted from the rail holding plate 45 through the connecting member 59. This causes both timing pulleys 52 and 53 to rotate, and the rotation of the timing pulley 53 causes the timing pulley 54 to rotate. As a result, the movement of the timing belt V3 causes the timing pulley 55 to rotate, which in turn causes the anvil 15 to rotate.

[0071] Details of the structure of the ultrasonic welding apparatus described above are disclosed in US2017 / 0027762A1, the entire disclosure of which is incorporated herein by reference.

[0072] Here, the relationship between the rotational position and linear movement position of the anvil 15 about the axis L1 in FIG. 3 is set by the cam groove 3a as follows, for example.

[0073] In the range (first section) from rotational position R0 to rotational position R1 in FIG. 8, the anvil 15 accelerates from the origin position of linear motion (FIG. 9) toward the stroke end (FIG. 10) (hereinafter, this direction is referred to as forward).

[0074] In the range from rotational position R1 to rotational position R2 (second section), the anvil 15 moves forward at a constant speed (first speed V1). During this movement, the web W is welded between the horn 14 and the anvil 15.

[0075] In the range from rotational position R2 to rotational position R3 (third section), the anvil 15 decelerates (backward acceleration is applied to the anvil 15) so as to stop at the stroke end (FIG. 10) at rotational position R3. In this example, the web W is not welded while the anvil 15 moves from the rotational position R2 to the original rotational position R0.

[0076] In the range from rotational position R3 to rotational position R4 (fourth section), the anvil 15 accelerates backward from the stroke end toward the origin position.

[0077] In the range from rotational position R4 to rotational position R5 (fifth section), the anvil 15 moves backward at a constant speed (second speed V2).

[0078] In the range from rotational position R5 to rotational position R0 (sixth section), the anvil 15 decelerates (forward acceleration is applied to the anvil 15) so as to stop at the origin position at rotational position R0.

[0079] The transport drum 200 in FIG. 2 rotates at a constant peripheral speed, and therefore the welding unit 6 including each anvil and horn also rotates at a constant peripheral speed together with the transport drum 200. On the other hand, as shown in FIG. 8, the first to third sections T1 to T3 corresponding to the outbound leg OB are longer in distance than the fourth to sixth sections T4 to T6 corresponding to the inbound leg IB. In this example, the first speed V1 of the anvil 15 in the second section T2 where welding is performed is slower than the second speed V2 of the anvil 15 in the fifth section T5 where welding is not performed. Therefore, the weld strength is stable even when welding is performed only on the forward path. On the other hand, in this example, the second speed V2 is greater than the first speed V1, and the average movement speed of the anvil 15 on the return path IB is greater than the average movement speed of the anvil 15 on the outgoing path OB. Therefore, the time it takes for the anvil 15 to move from the origin position, pass through the stroke end, and return to the origin position again is not long. In this example, the moving mechanism 300 is configured so that the average moving speed of the anvil 15 in the outgoing path OB during which the ultrasonic energy is applied is smaller than that in the returning path.

[0080] In this way, the speed difference of the anvil is obtained by forming the cam groove 3a in FIG. 3 asymmetrically so that the cam (follower) 23 in FIG. 3 is positioned at one end position and the other end position in the axial direction of the cam drum at rotational position R0 (origin position) and rotational position R3 (stroke end) in FIG. 8.

[0081] In this example, the control device 500 controls the ultrasonic generator 16 to perform welding only on the forward path, but it may also have modes for controlling the ultrasonic generator 16 to perform welding only on the return path or on both the forward and return paths.

[0082] Next, an example of the ultrasonic welding method of the present invention will be outlined.

[0083] As shown in FIG. 2, the web W is transported in the circumferential direction by the transport drum 200. As the conveying drum 200 rotates, the anvil 15 moves back and forth in the direction of the axis L1 of the conveying drum 200, as shown in FIGS. The web W is clamped between the anvil 15 and the horn 14 as the anvil 15 reciprocates in an outgoing path OB (FIG. 9) and an ingoing path IB (FIG. 10).

[0084] 9 is vibrated to apply ultrasonic energy to the web W sandwiched between the anvil 15 and the horn 14. The horn 14 vibrates, for example, in a direction intersecting the plane Ws of the web W.

[0085] In this example, the anvil 15 in FIG. 9 moves linearly from the origin position to the stroke end along the outward path OB, and in the welded region α corresponding to the second section, the anvil 15 moves at a first speed V1. In the welding region α, the control device 500 (Figure 3) vibrates the horn 14 via the ultrasonic generator 16, thereby applying ultrasonic energy to the web W clamped between the anvil 15 and the horn 14, and a welding portion S shown in gray in Figure 10 is formed in the web W. In this example, the anvil 15 moves so as to overrun the welding region α of the web W, and the horn 14 may be controlled not to vibrate in the overrun region β.

[0086] On the other hand, in case the web W shifts in a direction intersecting the conveying direction (the direction of the axis L1), the horn 14 may be set to vibrate not only in the welding area α, but also just before entering the welding area α and just after leaving the welding area α.

[0087] During the return path IB in which the anvil 15 in FIG. 10 returns from the stroke end to the origin position, the control device 500 controls the ultrasonic generator 16 so as not to apply ultrasonic energy to the web W. When ultrasonic energy is not applied to the web W, the horn 14 may be controlled not to vibrate.

[0088] In this example, the average movement speed of the anvil 15 on the outgoing path OB is smaller than the average movement speed of the anvil 15 on the returning path IB. In particular, the movement speed of the anvil 15 passing through the welded area α on the outgoing path OB is smaller than the movement speed of the anvil 15 passing through the welded area α on the returning path IB.

[0089] In the welding region α, the amplitude of the ultrasonic waves, the pressing force of the horn 14 and the anvil 15 against the web W, the moving speed of the anvil 15, the welding area per unit area, and the number of welding surfaces may be changed as appropriate.

[0090] As described above, the preferred embodiment has been described with reference to the drawings, but those skilled in the art will easily imagine various changes and modifications within the obvious scope upon reading this specification. For example, the anvil may be positioned radially inward of the outer periphery of the web support member, and the horn may be positioned radially outward of the outer periphery. The drum may be provided with only one set of horn and anvil, or multiple sets of horn and anvil. Furthermore, portions of the pants-type wearing article other than the so-called side seals may be welded. Therefore, such changes and modifications are to be construed as falling within the scope of the present invention as defined by the claims. [Industrial Applicability]

[0091] The present invention can be used in production equipment for disposable wearing articles such as disposable pants, diapers, and sanitary products, as well as in production equipment for medical wound dressings and the like. [Explanation of symbols]

[0092] 1: ultrasonic welding device 2: drive shaft support member 2a: through hole 3: cam drum 3a: cam groove 4: drive shaft 4a: pulley 5: rotating drum 5a: disc 5b: covering wall 5c: adjusting plate 5e: screw hole 6: welding unit 7: power transmission mechanism 8: slip ring 9: rotary joint 10: Motor 10a: Pulley 11: Wire guide member 12: Pipe connection member 14: Horn 15: Anvil 16: Ultrasonic generator 17: Cooling jacket 18: Mounting portion 19: Base 20: Horn holding mechanism 21: Anvil holding mechanism 23: Cam follower 42: Covering member 42a: Bottom plate 42b: Side plate 42c: Insertion hole 43: Horn holding member 44: Web support member 44a: Outer circumferential surface 44b: Bending portion 45: Rail holding plate 46: Rail 47: Slider 48: Main body portion 49-51: Rotating shaft 52-55: Timing pulley 59: Connecting member 70: Disposable diaper 70a: Front abdomen 70b: Back 70c: Crotch 200: Transport drum 300: Movement mechanism 500: Control device Ab: absorber D1: welding area D2: width F1: lead-in roller F2: lead-out roller L: leg hole L1: axis L2: straight line S: welding area OB: Outbound IB: Inbound P1: Conveying process P2: Leg hole forming process P3: Absorbent body joining process P4: Folding process P5: Welding process P6: Cutting process V1: Belt V2, V3: Timing belt W: Web Ws: Web surface α: Welded area β: Overrun area

Claims

1. a conveying drum (200) that conveys the web (W) along an outer peripheral surface (44a) while rotating; At least one horn (14) arranged on one side of the outer circumferential surface (44a) in the radial direction of the conveying drum (200) and rotating together with the conveying drum (200); At least one anvil (15) is arranged on the other side of the outer circumferential surface (44a) of the conveying drum (200) in the radial direction, and rotates together with the conveying drum (200); a moving mechanism (300) that reciprocates the anvil (15) in the axial direction (L1) of the conveying drum (200) in accordance with the rotation of the conveying drum (200) and clamps the web (W) between the anvil (15) and the horn (14) on the outward path (OB) and the return path (IB) of the anvil (15); an ultrasonic generator (16) that vibrates the horn (14) to apply ultrasonic energy to the web (W) sandwiched between the anvil (15) and the horn (14); a control device (500) that vibrates the horn (14) via the ultrasonic generator (16) to apply ultrasonic energy to the web (W) during either the outgoing path (OB) or the returning path (IB), and controls the horn (14) so ​​as not to apply ultrasonic energy to the web (W) during the other of the outgoing path (OB) or the returning path (IB), The moving mechanism (300) is configured so that the anvil (15) overruns beyond a welding area (α) where the web (W) is to be welded; The control device (500) controls the ultrasonic generator (16) so as not to vibrate the horn (14) in the overrun region (β), The moving mechanism (300) moves the anvil (15) at a constant speed when the anvil (15) moves through the welding region (α), and starts decelerating the anvil (15) when the anvil (15) has passed through the welding region (α); The moving mechanism (300) is configured so that the average moving speed of the anvil (15) in one of the outgoing path (OB) and the returning path (IB) to which the ultrasonic energy is applied is smaller than that in the other path. Ultrasonic welding equipment.

2. 2. The ultrasonic welding apparatus according to claim 1, wherein the control device (500) is configured to control the ultrasonic generator (16) so as not to vibrate the horn (14) when ultrasonic energy is not applied to the web (W).

3. a conveying drum (200) that conveys the web (W) along an outer peripheral surface (44a) while rotating; At least one horn (14) arranged on one side of the outer circumferential surface (44a) in the radial direction of the conveying drum (200) and rotating together with the conveying drum (200); and at least one anvil (15) arranged on the other side of the outer circumferential surface (44a) in the radial direction of the conveying drum (200), the anvil (15) rotating together with the conveying drum (200), A step of transporting the web (W) by the transport drum (200); a step of reciprocating the anvil (15) in the direction of the axis (L1) of the conveying drum (200) in accordance with the rotation of the conveying drum (200), and clamping the web (W) between the anvil (15) and the horn (14) on the outward path (OB) and the return path (IB) of the anvil (15); vibrating the horn (14) to apply ultrasonic energy to the web (W) sandwiched between the anvil (15) and the horn (14); and a step of vibrating the horn (14) via an ultrasonic generator (16) of the ultrasonic welding device to apply ultrasonic energy to the web (W) during either the outgoing path (OB) or the returning path (IB), and controlling the ultrasonic generator (16) so that ultrasonic energy is not applied to the web (W) during the other of the outgoing path (OB) or the returning path (IB), The anvil (15) moves the web (W) so as to overrun beyond the welding area (α) to be welded, The horn (14) is not vibrated in the overrun region (β), The anvil (15) moves at a constant speed when moving through the welding area (α), and starts to decelerate when it has passed through the welding area (α); The anvil (15) reciprocates so that the average moving speed of the anvil (15) in one of the outgoing path (OB) and the returning path (IB) to which the ultrasonic energy is applied is smaller than that in the other path. Ultrasonic welding method.

4. 4. The ultrasonic welding method according to claim 3, wherein the horn is controlled not to vibrate when ultrasonic energy is not applied to the web.

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