Flap folding system for disposable article to be worn

A flap folding system for a disposable article, includes: main pads each for receiving a main body on a main holding surface thereof provided along a conveyance circle about a main rotation shaft and moving along the conveyance circle following rotation of the main rotation shaft while holding the main body on the main holding surface; a pair of side pads provided for each main pad adjacent to the conveyance circle of the main pad each for receiving an end portion of the flap in a girth direction on a sub-holding surface thereof provided along the conveyance circle and holding the end portion of the flap on the sub-holding surface; and a folding mechanism for rotating the side pads with respect to the main pad so that the sub-holding surfaces of the side pads oppose the main holding surface of the main pad, thereby folding the flap.

TECHNICAL FIELD

The present invention relates to a folding system for side flaps of disposable worn articles.

BACKGROUND ART

Folding systems for folding disposable worn articles have been proposed in the art (see the first to third patent documents below). For example, in the second patent document, end portions of an article are folded by swing arms adjacent to a member for holding the article. However, the swing arms only swing so as to lift up end portions of articles, and if pliant portions such as flaps of worn articles are attempted to fold with such a folding device, variations may occur in the fastening positions.

CITATION LIST

Patent Document

SUMMARY OF INVENTION

Technical Problem

However, with a conventional folding system, it is not possible to accurately fold wide, soft portions such as side flaps of worn articles.

It is therefore an object of the present invention to provide a folding system capable of accurately folding side flaps of a disposable worn article.

Solution to Problem

In order to achieve the object set forth above, a flap folding system of the present invention is a device for folding a flap of a worn article having: a main body including a back portion covering a rear torso of a wearer, a crotch portion covering a crotch of the wearer, and a front portion covering a front torso of the wearer; and a flap extending in a girth direction from an edge portion of one of the back portion and the front portion of the main body to be fastened to the other one of the back portion and the front portion, the folding system comprising: a main rotation shaft; a plurality of main pads each for receiving at least the main body on a main holding surface thereof provided along a (virtual) conveyance circle about the main rotation shaft and moving along the conveyance circle following rotation of the main rotation shaft while holding the main body on the main holding surface; a pair of side pads provided for each of the main pads adjacent to each of the main pads on the conveyance circle for receiving at least an end portion of the flap in the girth direction on sub-holding surfaces thereof provided along the conveyance circle and holding the end portion of the flap on the sub-holding surfaces; and a folding mechanism for rotating the pair of side pads with respect to each of the main pads so that the sub-holding surfaces of the pair of side pads oppose the main holding surface of each of the main pads, thereby folding the flap.

Advantageous Effects of Invention

With the present invention, flaps are folded while end portions of the flaps are held by the holding surfaces, it is possible to accurately fold wide, soft flaps.

DESCRIPTION OF EMBODIMENTS

It is preferred in the present invention that the folding mechanism rotates the pair of side pads with respect to the main pad to a position such that the sub-holding surfaces oppose the main holding surface and the sub-holding surfaces are parallel to the main holding surface.

In this aspect, the rotation is done to a position (the squarely-opposing position) where the sub-holding surfaces oppose, and are parallel to, the main holding surface, i.e., the sub-holding surfaces squarely oppose the main holding surface, thereby allowing for more accurate folding of flaps.

It is preferred in the present invention that the folding mechanism includes: arms rotating about a pair of first axes parallel to the main rotation shaft; wrists rotatably supporting the side pads about a pair of second axes parallel to the first axes at a tip of the arms; and a driving mechanism for rotating the arms and the wrists in a predetermined rotation direction so as to fold the flap.

In this aspect, the side pad is rotatably supported via both the arm and the wrist, thereby allowing the sub-holding surface of the side pad to be squarely facing the main holding surface.

It is preferred in the present invention that the driving mechanism includes: an arm rotating mechanism for rotating the arm about the first axis so that the side pad moves from a first position adjacent to the main pad to a second position on an outer (circumferential) side of the main pad as the main pad rotates along the conveyance circle following the rotation of the main rotation shaft; and a wrist rotating mechanism for rotating the side pad about the second axis at the wrist following the rotation of the arm by the arm rotating mechanism.

In this aspect, the side pad rotates about the wrist while revolving together with the arm, and smooth folding can therefore be expected.

It is preferred in the present invention that the main pad and the side pads pick up a laminated web to be the worn article at a pickup position upstream of a folding position where the folding is done, and the main pad hands over the laminated web to a conveyer device downstream at a hand-over position downstream of the folding position.

It is preferred in the present invention that the folding system further includes a severing device for severing the laminated web being stretched along the conveyance circle by the main pad and the side pads at a severing position between the pickup position and the folding position.

In this aspect, the web is held in a stretched state, thereby allowing for accurate severing.

It is preferred in the present invention that the holding of the main body by the main pad is done at least in an area of the main pad where the side pads oppose the main pad.

In this aspect, fastening is done in a state where the main body to which the flap is fastened is held and the flap is also held, thereby allowing for accurate fastening.

In the present invention, a first fastener member may be provided on a skin-contact surface side of the flap to be folded, and a second fastener member may be provided on the main body on which the folded flap lies so as to engage with the first fastener member.

In the present invention, the main pads, the pairs of side pads and the folding mechanisms may be arranged in two rows along the conveyance circle, with the main pads of the two rows arranged in a staggered pattern with each other.

In this aspect, two rows of worn articles arranged in a staggered pattern obtained by severing a single web in a generally S-shaped pattern can be folded in parallel.

The present invention will be understood more clearly from the following description of preferred embodiments taken in conjunction with the accompanying drawings. Note however that the embodiments and the drawings are merely illustrative and should not be taken to define the scope of the present invention. The scope of the present invention shall be defined only by the appended claims. In the accompanying drawings, like reference numerals denote like components throughout the plurality of figures.

Embodiment 1 of the present invention will now be described with reference to the drawings.

As shown inFIG. 10, a diaper1of Embodiment 1 includes a diaper body2, and a pair of flaps3. The diaper body2includes a front portion20covering the front torso of the wearer, a back portion21covering the rear torso of the wearer, and a crotch portion22covering the crotch between the front portion20and the back portion21.

As shown inFIG. 1B, each flap3extends out from an edge portion E1of the diaper body2in a girth direction Y.

A first fastener member formed by a male touch fastener4is fixed to a skin-contact surface side3aof an end portion E2of each flap3in the girth direction Y.

On the other hand, a second fastener member formed by a female touch fastener5is provided on a non-skin-contact surface2bof the front portion20. As shown inFIG. 1C, the male touch fasteners4engage with the female touch fastener5.

Note that where the non-skin-contact surface2bof the diaper body2is formed by a non-woven fabric, the second fastener member may be formed by the non-woven fabric.

The term “skin-contact surface side” as used herein refers to the side which faces the skin surface of the wearer when the diaper1is worn, and the “non-skin-contact surface side” refers to the side opposite to the skin-contact surface side.

An adsorbent body (not shown) is provided on the diaper body2.

Three-dimensional gathers may be provided on the diaper body2.

The diaper body2may include around-leg portions23which have been cut so as to conform to the legs of the wearer. Elastic members formed by rubber threads, or the like, for example, may be provided so as to conform to the legs of the wearer in the around-leg portion23or portions of the flaps3that are connected to the around-leg portions23.

Moreover, an elastic member for fitting the diaper1to the wearer may be provided in portions of the front portion20and the back portion21of the diaper body2which are to be present around the torso and in the flaps. The elastic member may be, for example, a plurality of rubber threads or rubber tapes, a material including a film or a thermoplastic resin, or the like.

A laminated web W to be the diaper1is folded in two in the crotch portion22as shown inFIG. 1A, and is folded so that a skin-contact surface2aof the back portion21and the skin-contact surface2aof the front portion20indicated by a two-dot-chain line lie on each other. As shown inFIG. 10, the skin-contact surface side3a(FIG. 1B) of the flap3is folded toward the female touch fastener5of the front portion20of the diaper body2, and the diaper1is shipped with the set of fasteners4and5engaged with each other and the pair of flaps3tentatively attached to the diaper body2.

When wearing the diaper1, a wearer puts it on as if it were a pants-type diaper, with the flaps3tentatively attached to the diaper body2. On the other hand, if the diaper1does not sufficiently fit to the wearer, the male touch fasteners4of the flaps3may be once taken off the female touch fastener5of the diaper body2, and the male touch fasteners4may be re-attached to the female touch fastener5, thereby fitting the diaper1to the wearer.

Next, a folding system for severing the diaper1and folding the flaps3as shown inFIGS. 1A to 1Cwill be described.

As shown inFIG. 2, this folding system includes a folding drum9. A cutter roller32is arranged so as to oppose the folding drum9.

The folding drum9includes a plurality of folding units10rotating about a main rotation shaft91. The folding drum9includes a fixed frame15for rotatably supporting the main rotation shaft91ofFIG. 7, and a rotating frame16rotatably supported about the fixed frame15. A torque from a motor (not shown) is input to the main rotation shaft91, and the rotating frame16rotates about the main axis LM following the rotation of the main rotation shaft91.

As shown inFIGS. 6A and 6B, each folding unit10includes an anvil31(FIG. 3), a main pad11, a pair of side pads12, and a pair of folding mechanisms40.

Each folding unit10including the anvil31(FIG. 3), the main pad11, the side pads12and the folding mechanisms40is attached to the rotating frame16shown inFIG. 7, and rotates about the main axis LM together with the rotating frame16following the rotation of the main rotation shaft91.

As shown inFIG. 4, the anvil31forms a severing device30together with the cutter roller32and a blade33.

The severing device30severs the web W into individual diapers downstream of the pickup position1P of the web W.

In this folding system, the main pad11and the side pads12ofFIG. 2pick up the web W to be the diaper1at the pickup position1P upstream of the folding position3P where the folding is done. The main pad11hands over the diaper1to a conveyer device (not shown) at the hand-over position4P downstream of the folding position3P. The folding position3P is located downstream of the severing position2P.

The main pad11receives at least the main body2on a main holding surface11swhich is provided along the conveyance circle C (FIG. 5C) about the main rotation shaft91. Then, the main pad11moves along the conveyance circle C following the rotation of the main rotation shaft91while holding the main body2on the main holding surface11s. As shown inFIG. 6A, a plurality of air holes h1are open on the main holding surface11sfor holding the main body2through suction by a negative pressure, for example.

For each main pad11, a pair of side pads12are arranged adjacent to the main pad11on the conveyance circle C (FIG. 5C) of the main pad11. The side pads12receive at least the end portions E2of the flaps3in the girth direction Y ofFIG. 3on the sub-holding surfaces12swhich are provided along the conveyance circle C (FIG. 5C). Then, the end portions E2of the flaps3are held on the sub-holding surfaces12s. A plurality of air holes h2ofFIG. 6Aare open in the sub-holding surface12sfor holding the flaps3through suction by a negative pressure, for example.

The pressing mechanism50includes an endless third belt B3wound around a plurality of rollers51. The third belt B3presses an area of the diaper body2ofFIG. 1Awhere the flaps3are not lying thereon on the folding drum9. Thus, the two-folded area of the diaper body2that cannot be held by the suction of the main holding surface11sis pressed from the outer (circumferential) side of the folding drum9.

The folding mechanism40ofFIG. 4rotates the pair of side pads12with respect to the main pad11so that the sub-holding surfaces12sof the pair of side pads12oppose the main holding surface11sof the main pad11as shown inFIG. 5C, thereby folding the flaps3.

The folding mechanism40will now be described.

As shown inFIGS. 4,5A and5C, the folding mechanism40rotates the pair of side pads12with respect to the main pad11to a position such that the sub-holding surfaces12soppose the main holding surface11sand the sub-holding surfaces12sare parallel to the main holding surface11s. Each folding mechanism40includes an arm13, a wrist14, and a driving mechanism41.

The arm13ofFIG. 7rotates about one of a pair of first axes L1parallel to the main rotation shaft91. At the tip of each arm13, the wrist14rotatably supports the side pad12about one of a pair of second axes L2. The second axes L2are parallel to the first axes L1. The driving mechanism41ofFIG. 4rotates the arm13and the wrist14in a predetermined rotation direction so as to fold the flap3.

InFIG. 4, the driving mechanism41includes a pair of arm rotating mechanisms42and a pair of wrist rotating mechanisms43. Each folding unit10has a left-right symmetric structure about the normal L3of the drum. One arm rotating mechanism42and one wrist rotating mechanism43will now be described.

As each main pad11rotates along the conveyance circle C following the rotation of the main rotation shaft91(FIG. 2), the arm rotating mechanism42rotates the arm13about the first axis L1so that the side pad12moves from the first position P11adjacent to the main pad11ofFIG. 4to the second position P12on the outer (circumferential) side of the main pad11ofFIG. 5C.

On the other hand, the wrist rotating mechanism43rotates the side pad12about the second axis L2at the wrist14following the rotation of the arm13by the arm rotating mechanism42. With the rotation of the wrist14and the rotation of the arm13, the side pad12rotates to the second position P12and the sub-holding surface12srotates to oppose the main holding surface11s, thereby folding the flap3, as shown inFIG. 5C.

The air holes h1of the main pad11are provided at least in portions where the sub-holding surfaces12sof the side pads12oppose the main pad11or areas in the vicinity thereof. Therefore, it is possible to hold not only the flaps3but also the diaper body2even during the folding process.

Next, the details of the structure of the arm rotating mechanism42will be described.

As indicated by a two-dot-chain line ofFIG. 2, a circumferential cam groove17is formed in the fixed frame15. On the other hand, a rotating member44is rotatably supported by the rotating frame16ofFIG. 7for each arm rotating mechanism42. A cam follower18is attached to the rotating member44at a position that is eccentric with respect to the rotating member44. A first pulley P1is attached coaxially to the rotating member44.

The rotating member44rotates about the main rotation shaft91together with the rotating frame16while the rotating member44swings as the cam follower18ofFIG. 2is guided along the cam groove17, thereby making the first pulley P1reciprocally rotate together with the rotating member44.

An arm rotation shaft45is rotatably attached to the rotating frame16. A second pulley P2and the arm13are attached respectively to one end and the other end of the arm rotation shaft45. As the first pulley P1reciprocally rotates, the arm13swings via an endless first belt B1, the second pulley P2and the arm rotation shaft45, thereby making the side pad12reciprocate between the first position P11ofFIG. 4and the second position P12ofFIG. 5C.

Next, the details of the structure of the wrist rotating mechanism43will be described.

A third pulley P3is provided coaxially with the arm rotation shaft45on the other end of the arm rotation shaft45ofFIG. 7. The third pulley P3is fixed to a rotating frame16A so as not to rotate.

As shown inFIGS. 5A and 5B, fourth to sixth pulleys P4to P6are arranged around the third pulley P3. An endless second belt B2is wound around these pulleys P3to P6. The sixth pulley P6ofFIG. 7is fixed to one end of the rotation shaft forming the wrist14. The side pad12is fixed to the other end of the wrist14.

Now, if the first pulley P1ofFIG. 5Arotates in the closing direction R1, the first belt B1also rotates in the closing direction R1, thereby making the second pulley P2and the arm13rotate in the closing direction R1. On the other hand, since the third pulley P3ofFIG. 5Bdoes not rotate, the second belt B2rotates in the closing direction R1following the rotation of the arm13ofFIG. 5A, and the sixth pulley P6ofFIG. 5Brotates in the closing direction R1. Thus, the side pad12rotates in the closing direction R1together with the wrist14.

Therefore, the wrist14rotates in the closing direction R1following the rotation of the arm13ofFIG. 5Ain the closing direction R1. Thus, as shown inFIG. 5C, as the arm13rotates in the closing direction R1, the side pad12rotates about the first axis L1while rotating about the second axis L2. The side pad12rotates to an attitude such that the sub-holding surface12sis parallel to the main holding surface11s, so that the sub-holding surface12sopposes the main holding surface11s.

Thus, by the rotation, the flaps3of the diaper1ofFIG. 1Bare folded as shown inFIG. 10.

Note that the action by which the side pad12ofFIG. 5Creturns from the second position P12back to the first position P11as shown inFIG. 4(the opening action) is reverse from the rotation action in the closing direction R1, and will not be further described below.

Next, the operation of producing diapers1from the web W will be described.

As shown inFIG. 1A, the web W in which the diaper bodies2are folded in two is supplied, in the form of a continuous member, onto the folding drum9at the pickup position1P ofFIG. 2.

In the angle θ1including the pickup position1P, the side pads12are in the open, first position P11. Therefore, the main holding surface11sand the sub-holding surfaces12sshown inFIG. 3receive the web W by sucking and holding the web W. In this process, the diaper body2is placed on the main holding surface11swith the flaps3bridging between the main holding surface11sand the sub-holding surfaces12s, as shown inFIG. 3, thus holding the web W on these surfaces11sand12s.

Note that through the angle θ1ofFIG. 1, the diameter of the cam groove17is constant.

As the folding drum9ofFIG. 2rotates in this state, the web W being stretched along the conveyance circle C by the main pad11and the side pads12is severed along the severing line CL ofFIG. 1Aat the severing position2P between the pickup position1P and the folding position3P into individual diapers1as shown inFIG. 1B.

The severed diaper1is folded as follows at the folding position3P ofFIG. 2.

In the angle θ2about the main rotation shaft91, the diameter of the cam groove17gradually decreases as it extends downstream Y1. Through the angle θ2, as the folding unit10rotates downstream Y1, the arms13and the wrists14rotate in the closing direction R1(FIG. 5A).

That is, as the folding unit10rotates toward the folding position3P, the cam follower18is guided along the cam groove17so that the arm13rotates in the closing direction R1and the wrist14ofFIG. 5Arotates in the closing direction R1as described above. As the arms13and the wrists14rotate so that the sub-holding surfaces12ssquarely oppose the main holding surface11sas indicated by the folding position3P ofFIG. 5C, the flaps3ofFIG. 10are folded and the male touch fasteners4come into contact with, and engage with, the female touch fastener5.

At this point, as the sub-holding surfaces12ssquarely oppose the main holding surface11s, the touch fasteners4and5engage with each other while squarely opposing each other, thus making the engagement between the touch fasteners4and5reliable.

Thus, the flaps3of the diaper1ofFIG. 1Care folded and the folded flaps3are fixed to the diaper body2via the male touch fasteners4and the female touch fastener5, thereby making it possible to hold the flaps3in a folded state.

The folded state may be maintained through the angle θ3about the main rotation shaft91ofFIG. 2. Then, in the angle θ4, the closed arms13and the closed wrists14rotate in the opening direction.

Note that through the angle θ4, the diameter of the cam groove17gradually increases as it extends downstream Y1.

Before the arms13and the wrists14start opening, suction through the air holes h2provided in the sub-holding surfaces12sofFIG. 6Ais discontinued.

After the arms13and the wrists14are opened, the diaper1is handed over to the conveyer device (not shown) at the hand-over position4P ofFIG. 2. In this hand-over process, suction through the air holes h1provided in the main pad11ofFIG. 6Ais discontinued.

Note that the folding unit10which has handed over the diaper1continues to rotate toward the pickup position1P.

In Embodiment 2, a single folding drum is used to sever two strips of laminated web W shown inFIG. 9Ainto individual diapers1and folding the flaps3.

As shown inFIG. 10, in the present embodiment, two rows of folding units10are arranged in a staggered pattern. With the present embodiment, the anvil31of a folding unit10of one row protrudes into between folding units10and10of the other row.

That is, in Embodiment 1 ofFIG. 3, the anvil31of a folding unit10of one row is placed between folding units10and10of the same row. In contrast, in Embodiment 2, the anvil31of a folding unit10of one row protrudes toward the other row as shown inFIGS. 11A and 11B.

While preferred embodiments have been described above with reference to the drawings, obvious variations and modifications will readily occur to those skilled in the art upon reading the present specification.

For example, a flap may extend out in the girth direction from an edge of the front portion. The first and second fastener members may be absent, and the flaps may be tentatively fastened to the main body by a hot-melt adhesive.

Pads do not need to be sucked by a negative pressure, but a web may be held on pads by piercing a plurality of needles through the web.

The mechanism for rotating the arms and the wrists may be gears instead of belts. Mechanisms for rotating the arms and the wrists may be provided separately from each other.

It is not necessary to rotate both the arms and the wrists as long as the side pads are rotated so that the sub-holding surfaces oppose the main holding surface.

Thus, such variations and modifications shall fall within the scope of the present invention as defined by the appended claims.

INDUSTRIAL APPLICABILITY

The present invention is applicable to folding systems for folding flaps of worn articles such as disposable diapers.

DESCRIPTION OF THE REFERENCE NUMERALS