Patent Description:
Elastic threads, so-called rubber threads, are often arranged around the leg holes of disposable pants and diapers.

One conventional example of a device and a method of this type will be described using <FIG> and <FIG>.

<FIG> is a conceptual diagram showing a method for manufacturing disposable pants from a layered material W in which elastic threads F are sandwiched between a pair of sheets S, and <FIG> is a perspective view of a device for manufacturing the layered material W.

As shown in <FIG>, the conventional manufacturing device includes a pair of nip rolls <NUM>, a pair of needles <NUM>, a pair of needle bodies <NUM> and a pair of belts <NUM>. The pair of nip rolls <NUM> are arranged with their axes <NUM> parallel to each other.

The pair of needles <NUM> are arranged upstream of the nip roll <NUM> in the conveyance direction X of the sheets S for guiding and arranging the elastic threads F between the pair of sheets S of <FIG> while dispensing the elastic threads F through through holes <NUM>, through which the elastic threads F pass. The pair of needles <NUM> of <FIG> are held in the needle bodies <NUM>, and the needle bodies <NUM> are attached to the belts <NUM>. The needle bodies <NUM> reciprocate with the reciprocating rotation of the belts <NUM>.

The pair of sheets S of <FIG> are supplied to the nipping section <NUM> between the pair of nip rolls <NUM> of <FIG>, and a plurality of elastic threads F are supplied meandering in a wave-like form between the sheets. After they are supplied, the layered material W is produced in which the elastic threads F are sandwiched between the pair of sheets S.

Thereafter, after leg holes H are formed in the layered material W, the layered material W is folded in two, sealed at side seals SS, and then cut into individual worn articles N. Thus, a worn article N is produced with the elastic threads F arranged along the leg holes H.

Devices and methods for arranging such elastic threads F are well known in the art (the first patent document).

[FIRST PATENT DOCUMENT] <CIT> (FIG. <NUM> to FIG. 5A)
<CIT> discloses an apparatus for manufacturing wearing articles including: a pair of nip rolls for nipping a first web and a first elastic member; a first moving section movable in a direction crossing the first web; and a first guide head provided on the first moving section for feeding the first elastic member at a position upstream of a position at which the first web is nipped, wherein the radius of at least one of the pair of nip rolls is about <NUM> to about <NUM>, and a distance between a plane including axes of the pair of nip rolls and a point at which the first guide head releases the first elastic member is about <NUM> or less. <CIT> discloses a vibration damping method for band-shaped bodies capable of efficiently damping the vibration of all steel sheets and band-shaped bodies exclusive of the steel sheets regardless of whether these bodies are magnetic or nonmagnetic. The vibration damping device has vibration detectors of a contactless type for detecting the vibration quantity of the band-shaped body (steel sheet) traveling along a traveling plane. The signals from these vibration detectors are inputted to a controller. The positions thereof and the vibration quantity are detected by this controller and are inputted to amplifiers. The pressure waves meeting the vibration quantity are oscillated toward the position of the antinode of the vibration mode of the steel sheet from prescribed pressure wave generators, by which the vibration of the steel sheet is damped. The band-shaped bodies to be subjected to vibration damping are not limited to the magnetic steel sheets alone and the vibration damping of the nonmagnetic materials is possible as well. <CIT> teaches to inhibit noise generation and deterioration of durability owing to belt vibration without deteriorating power performance. The vibration restraining device includes a primary pulley rotation number sensor and a secondary pulley rotation number sensor for detecting rotation speeds associating with vibration generated at a chord part of a metal belt which is not contacting with the pulleys at a side compressed along a forward direction from the primary pulley to the secondary pulley in the metal belt while the pulleys are rotating and a magnet force generation device, provided to face against the chord part, for generating magnetic force and an ECU for controlling the magnetic force generated by the magnetic force generation device. Based on the detected rotation speed, the ECU determines that vibration is generated at the chord part and, when the vibration generation is detected, magnetic force is generated by the magnetic force generation device.

The belts <NUM> of <FIG> are pulled alternately in the direction of rotation by a pair of pulleys 3P as they reciprocate, and thus the tension fluctuates periodically. This periodic tension fluctuation causes the belts <NUM> to vibrate in a direction orthogonal to surfaces 3a of the belts <NUM>, thereby causing the tips of the needles <NUM> to vibrate. Therefore, a mechanical guide member such as a linear guide has conventionally been provided to prevent the belts <NUM> or the needle bodies <NUM> from vibrating due to the vibration.

However, since the needle bodies <NUM> and the belts <NUM> are operated at a high speed, there is a risk that a mechanical guide member such as a linear guide mentioned above may be damaged due to friction. Therefore, there is naturally a limit to increasing the speed of operation.

Thus, an object of the present invention is to provide a device and a method for manufacturing a layered material capable of operating at a higher speed than before.

A manufacturing device of the present invention is a device for manufacturing a layered material W including an elastic thread F sandwiched between a pair of sheets S, including:.

On the other hand, a manufacturing method of the present invention is a method for manufacturing a layered material W including an elastic thread F sandwiched between a pair of sheets S, the method using a device for manufacturing the layered material W, the device including:.

According to the present invention, the stabilizer stabilizes the reciprocation of the needle <NUM>, and since the stabilizer is of a non-contact type, it causes no friction. Therefore, it is possible to operate at a higher speed than before.

In the present invention, the elastic thread F means a so-called thread rubber, but the material does not need to be rubber and may be any linear continuous elastomer as long as the material has a stretchable property.

In the present invention, the sheet S is continuous in the conveyance direction, and a web (nonwoven fabric) is generally employed as the sheet S.

The term "needle" does not mean a needle-like sharp pointed object, but rather an object which dispenses an elastic thread F from the through hole <NUM>, through which the elastic thread F passes.

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.

An embodiment of the present invention will now be described.

<FIG> show an embodiment of the present invention.

In <FIG>, a sheet S is supplied to each of a pair of nip rolls <NUM>, <NUM>, and elastic threads F are supplied between the pair of sheets S, S. The sheets S and the elastic threads F are layered together at the nipping section <NUM>. Note that in <FIG>, a pair of nip rolls <NUM> and a pair of placement units U are provided, and the pair of placement units U are provided symmetrically to each other. The pair of nip rolls <NUM>, <NUM> are in contact with each other in the nipping section <NUM> with the pair of sheets S and the elastic threads F therebetween.

The needle <NUM> may be provided with a plurality of through holes <NUM>, through which the elastic threads F pass, as clearly shown in <FIG>. As shown in <FIG>, the needles <NUM> are held on the needle bodies <NUM>.

The needle body <NUM> of <FIG> is attached to the belt <NUM>. The belt <NUM> forms a reciprocating section that reciprocates in a width direction Y of <FIG>, which intersects with the conveyance direction X of the sheet S. The needle <NUM> and the belt <NUM> form a part of the placement unit U of the elastic threads F.

Next, the placement unit U will be outlined.

As shown in <FIG>, each belt <NUM> is endless and wound around a pair of pulleys 3P of <FIG>.

The belt <NUM> indicated by a two-dot-chain line of <FIG> is driven by a motor <NUM> to reciprocally rotate via the pulleys 3P (<FIG>). The belt <NUM> is constantly tensioned by a cylinder <NUM> via a rod <NUM>, the motor <NUM> and the pulleys 3P (<FIG>). The cylinder <NUM> and the rod <NUM> prevent the belt <NUM> from slacking, and form a pressing mechanism that applies tension to the belt <NUM> so that the needle body <NUM> is close to a guide <NUM>.

As shown in <FIG>, the belt <NUM> is sandwiched between the plate-shaped needle body <NUM> and a mounting plate <NUM>, and the needle body <NUM> is attached to the surface 3a of the belt <NUM>. The guide <NUM> is arranged in the vicinity of the needle body <NUM> and the belt <NUM>. As shown in <FIG>, the guide <NUM> extends along the surface 3a of the belt <NUM> relative to the straight portion of the belt <NUM>.

The guide <NUM> of <FIG> includes an air tank <NUM> with an air passageway <NUM> formed therein, the air tank <NUM> being long along the belt <NUM>, and an air plate <NUM>, which covers an opening <NUM> formed on one side of the air tank <NUM> and includes a large number of outlet holes <NUM>. The outlet holes <NUM> of <FIG> are provided intermittently in the longitudinal direction <NUM> of the guide <NUM> for blowing out air. That is, the guide <NUM> of <FIG> is configured to push the belt <NUM>, to which the needle body <NUM> is attached, in the direction Z orthogonal to the surface 3a of the belt <NUM> by blowing out air.

As shown in <FIG>, in this example, the needle body <NUM> includes a pair of wings <NUM>, <NUM> projecting in a direction along the guide <NUM>. As clearly shown in <FIG>, a gap A is provided between the belt <NUM> and the guide <NUM> by the thickness of the needle body <NUM>. On the other hand, a minute gap is created between the needle body <NUM> and the guide <NUM> through which the air flowing out of the outlet holes <NUM> passes. This gap is so narrow that it cannot be represented in the figure, and forms an air layer. In other words, the needle body <NUM> of <FIG> includes a flat plate portion 11P that is surface-joined to the surface 3a of the belt <NUM>, and an air layer is formed between the flat plate portion 11P and the guide <NUM> by the air blowing out of the outlet holes <NUM>.

As shown in <FIG>, the large number of outlet holes <NUM> may be arranged in multiple rows (e.g., two rows) spaced apart from each other in the width direction 4D of the belt <NUM>. In this case, the air from the upper row of outlet holes <NUM> escapes upward and the air from the lower row of outlet holes <NUM> escapes downward, thereby increasing the probability with which the minute gap between the flat plate portion 11P of the needle body <NUM> and the guide <NUM> of <FIG> is maintained.

Next, the method for manufacturing the layered material W of <FIG> will be described.

As shown in <FIG>, a pair of sheets S are continuously supplied to the nipping section <NUM> between the pair of nip rolls <NUM>, and elastic threads F are continuously supplied from the through holes <NUM> of the needle <NUM> between the pair of sheets S. In this process, each needle <NUM>, together with the needle body <NUM>, reciprocates in a width direction Y by the drive of the belt <NUM> of <FIG>, and the elastic threads F are arranged in a wave-like form, as shown in this figure.

While the needle <NUM> is reciprocating, air constantly blows out of the outlet holes <NUM> of the guide <NUM> of <FIG>. On the other hand, the belt <NUM> is under tension as described above, and the air blowing out of the outlet holes <NUM> pushes the needle body <NUM> and the belt <NUM> of <FIG> in one direction in the direction Z orthogonal to the surface 3a of the belt <NUM>. Thus, the belt <NUM> and the needle <NUM> move in the width direction Y without swinging in the orthogonal direction Z.

On the other hand, since the needle body <NUM> and the belt <NUM> are not in contact with the guide <NUM>, it is possible to prevent the wear of these parts. Therefore, the belt <NUM> can operate at a high speed, which improves the productivity of the layered material W.

Otherwise, the structures and the method are similar to the conventional example shown in <FIG> and <FIG> discussed above, and the detailed description thereof is omitted. The placement unit U of <FIG> is described in <CIT> and <CIT>.

The invention conceived from the embodiments described above comprises the following preferred embodiments.

With a preferred manufacturing device, the guide <NUM> may be a magnetic guide instead of being an air guide. In the case of a magnetic guide, it may be a magnetic guide that makes use of magnetic repulsion.

In the case of these guides, an air layer is formed between the guide <NUM> and the needle body <NUM>.

That is, there is no limitation on the guide as long as the guide forms an air layer between the guide and the needle body to prevent them from contacting each other.

With a preferred manufacturing device, the reciprocating section is the belt <NUM>;.

In this case, since the belt <NUM> is pushed in one direction in the direction Z orthogonal to the conveyance direction X of the belt <NUM>, the belt <NUM> is unlikely to slack.

With a preferred manufacturing device, the guide <NUM> has a plurality of outlet holes <NUM> through which the air is blown out, the outlet holes <NUM> being arranged intermittently in the longitudinal direction <NUM> of the guide <NUM>.

In this case, since a plurality of air outlet holes <NUM> are provided in the longitudinal direction <NUM>, the force pushing the belt <NUM> by the blowing of the air is stabilized in the longitudinal direction <NUM>.

More preferably, a plurality of rows of outlet holes <NUM> of the guide <NUM> are provided spaced apart from each other in the width (vertical) direction 4D, which is orthogonal to the longitudinal direction <NUM> of the guide.

In this case, the air blown out through the plurality of rows of outlet holes <NUM> spreads out in the width direction 4D and forms a stable air layer.

More preferably, the needle body <NUM> includes the flat plate portion 11P that is surface-joined to the surface 3A of the belt <NUM>, the flat plate portion 11P facing the guide <NUM>, and an air layer of the air blown out through the outlet holes <NUM> is formed between the flat plate portion 11P and the guide <NUM>.

In this case, the air layer formed between the guide <NUM> and the flat plate portion 11P keeps constant the minute gap between the flat plate portion 11P and the guide <NUM>, thereby increasing the probability of realizing the anti-wear effect.

Preferably, the guide <NUM> includes the air tank <NUM>, which is long along the belt <NUM>, and the air plate <NUM>, which covers the opening <NUM> formed in the side surface of the air tank <NUM>, the side surface faces the surface of the belt <NUM>, and the outlet holes <NUM> are formed in the air plate <NUM>.

In this case, the cost of the guide <NUM> that is long along the belt <NUM> is reduced.

Preferably, a pressing mechanism is provided for applying tension to the belt <NUM> so that the flat plate portion 11P is close to the guide <NUM>.

In this case, the tension on the belt <NUM> keeps the flat plate portion 11P close to the guide <NUM>, and maintains a thin air layer between the guide <NUM> and the flat plate portion 11P.

Note that it is more preferred that the flat plate portion 11P is in contact with the guide <NUM> in a non-operating state when air is not blowing out.

With a preferred manufacturing method of the present invention, the stabilizer is the guide <NUM> extending along the surface 3a of the belt <NUM> (the reciprocating section); and
in the stabilizing step, the guide <NUM> presses the belt <NUM>, to which the needle body <NUM> is attached, in the direction Z orthogonal to the surface 3a of the belt <NUM> by blowing out air or by magnetic force, thereby suppressing swinging of the belt <NUM> in the orthogonal direction Z.

This prevents deterioration of the guide due to wear and allows for high speed operation.

Any feature illustrated and/or depicted in conjunction with one embodiment or preferred embodiments may be used in the same or similar form in one or more of the other embodiments, and/or may be used in combination with, or in place of, the other embodiments.

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, only one set of placement units may be provided. The guide may be a magnetic guide using magnetic repulsion instead of air blowing pressure.

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

Claim 1:
A device for manufacturing a layered material (W) including an elastic thread (F) sandwiched between a pair of sheets (S), comprising:
a pair of nip rolls (<NUM>) arranged with their axes (<NUM>) parallel to each other for nipping the elastic thread (F) between the pair of sheets (S) being conveyed in a conveyance direction (X);
a needle (<NUM>) arranged upstream of the nip rolls (<NUM>) in the conveyance direction (X) for guiding and arranging the elastic thread (F) between the pair of sheets (S) while dispensing the elastic thread (F) through a through hole (<NUM>), through which the elastic thread (F) passes;
a needle body (<NUM>) that holds the needle (<NUM>);
a reciprocating section, to which the needle body (<NUM>) is attached, for reciprocating in a width direction (Y), which intersects with the conveyance direction (X); and
a stabilizer that stabilizes the reciprocation of the reciprocating section,
wherein the stabilizer is a non-contact-type guide (<NUM>), wherein the guide (<NUM>) is an air guide or a magnetic guide.