Patent Application
20060272462
1. Field of the Invention
The present invention relates to a rotary cutter which comprises two rolls for holding a workpiece such as fibrous sheet therebetween so as to make cuts in the workpiece only halfway through its thickness from both sides thereof, and also relates to a method for manufacturing a fibrous product using the rotary cutter.
2. Description of the Related Art
Rotary cutters comprising two rolls have been widely used for making a desired pattern of cuts in fibrous products such as a nonwoven fabric, a stack of nonwoven fabrics, a stack of a nonwoven fabric and a fiber bundle layer, etc.
The rotary cutter 1 comprises a die roll 2 and an anvil roll 3 with their axes arranged parallel with each other. The die roll 2 includes a rotary shaft 4, a periphery 5 formed with a desired radius about the roll axis of the rotary shaft 4, and a plurality of cutting blades 6 projecting radially from the periphery 5. The die roll 2 is provided at its axially opposite ends with contact peripheries 7 and 7, which are formed with a radius slightly larger than the radius of the periphery 5. The cutting blades 6 projects lightly beyond the peripheries 7 and 7 to have their edges located radially outside the peripheries 7 and 7. On the other hand, the anvil roll 3 includes a rotary shaft 8 and a periphery 9 formed with a desired radius about the roll axis of the rotary shaft 8.
In this construction, the distance between the roll axis of the die roll 2 and the roll axis of the anvil roll 3 can be kept constant with the contact peripheries 7 and 7 kept in contact with the periphery 9 of the anvil roll 3. In addition, the cutting blades 6 provided on the die roll 2 can be pressed with desired force against the periphery 9 of the anvil roll 3 by pressing the contact peripheries 7 and 7 against the periphery 9 of the anvil roll 3 with desired force.
When the die roll 2 and the anvil roll 3 are driven to rotate in the directions of the arrows in synchronism with each other and a workpiece W is fed between the die roll 2 and the anvil roll 3, the workpiece W is locally cut by the cutting blades 6 with the workpiece W held between the edges of the cutting blades 6 of the die roll 2 and the periphery 9 of the anvil roll 3.
For example, the workpiece W comprises a substrate sheet Wa such as nonwoven fabric and fiber bundle layers Wb disposed on two sides of the substrate sheet Wa. The fiber bundle layer Wb is a bundle of fibers which individually extend continuously in a feed direction of the workpiece W. In other words, the individual fibers constituting the fiber bundle layer Wb extend in MD without interruption, before cutting with the cutter roller 1. The fiber bundle layers Wb are bonded to the substrate sheet Wa at bond lines Wc which are arranged at regular intervals in the feed direction (MD). When fed between the die roll 2 and the anvil roll 3, the workpiece W is held between the cutting blades 6 and the periphery 9 at positions between adjacent bond lines Wc, whereby the substrate sheet Wa is cut together with the fiber bundle layers Wb, forming cut lines Wd.
Thus, the fiber bundle layers Wb on two sides of the substrate sheet Wa are individually cut into separate portions each of which is fixed to the substrate sheet Wa at one bond line Wc so as to have ends obtained by formation of the cut lines Wd function as free ends. The resulting workpiece W can be used as a cleaning article for wiping the floor and the like, wherein the fiber bundle layers Wb are expected to have an effect of collecting dust like a brush.
In the rotary cutter 1 shown in
This results in that the individual fibers constituting the fiber bundle layers Wb are hardly separated from each other in the workpiece W having passed through the cutting process, so that when used as a cleaning article, for example, the fiber bundle layers Wb cannot take on a suitable brush-like form, whereby an expected duct collecting effect cannot be obtained.
In order to prevent the individual fibers constituting the fiber bundle layers Wb from being thermally fusion-bonded to each other along the cut lines Wd, accordingly, the workpiece W may be cut by adopting a so-called half-cut technique in which a workpiece is cut from one side only halfway through its thickness, instead of cutting the substrate sheet Wa and the fiber bundle layers Wb all together under high pressure. In this case, since the cutting force acts on only one of the fiber bundle layers Wb, thermal fusion-bonding between individual fibers can be eliminated or suppressed.
Japanese Unexamined Patent Publication No. 10-76494 discloses such a half-cut technique. In the technique disclosed in the above-identified Patent Publication, the edges of the cutting blades 6 of the rotary cutter shown in
However, if the half-cut technique disclosed in the above-identified Patent Publication is adopted to cut the workpiece W shown in
The present invention has been worked out in view of the shortcomings in the prior art set forth above. It is therefore an object of the present invention to provide a rotary cutter, in which cutting of a workpiece halfway through the thickness from both sides thereof can be done at once, and a method for manufacturing a fibrous product using the rotary cutter.
According to a first aspect of the present invention, there is provided a rotary cutter comprising a first roll rotatable about a first roll axis and a second roll rotatable about a second roll axis which is parallel to the first roll axis,
In the rotary cutter according to the first aspect of the present invention, the first roll and the second roll are driven to rotate in synchronism with each other so that the first cutting blade can be opposed to the second abutment at a distance apart and the first abutment can be opposed to the second cutting blade at a distance apart. When a workpiece is fed between the first roll and the second roll, the first cutting blade can penetrate only halfway through the workpiece from one side thereof and at the same time, the second cutting blade can penetrate only halfway through the workpiece from the other side thereof.
The rotary cutter according to the first aspect of the present invention may be constructed such that a first rib is provided to project radially from the periphery of the roll body of the first roll and the first cutting blade and the first abutment are formed in the first rib, and a second rib is provided to project radially from the periphery of the roll body of the second roll and the second cutting blade and the second abutment are formed in the second rib.
With the ribs each having one cutting blade and one abutment being provided on both the first roll and the second roll so as to be opposed to each other, a cut formed in one side of a workpiece having passed between the rolls can be located adjacent a cut formed in the other side of the workpiece. Accordingly, a completed product looks as if the two sides of the workpiece were cut at vertically opposed positions.
Preferably, the first and second abutments have a larger width than the edges of the first and second cutting blades.
With the width of the abutments being larger than that of the edges of the cutting blades, the abutments can serve as anvils, so that when the workpiece is held between the cutting blades and the abutments, the cutting blades easily penetrate halfway through the workpiece.
The rotary cutter according to the first aspect of the present invention may also be constructed such that the distance setting means includes a first contact periphery which is formed on the first roll with a radius larger than the periphery of the roll body of the first roll and a second contact periphery which is formed on the second roll with a radius larger than the periphery of the roll body of the second roll, wherein a distance between the first roll axis and the second roll axis is set by contact between the first contact periphery and the second contact periphery.
With the first contact periphery and the second contact periphery being kept in contact with each other, the distance between the first roll axis and the second roll axis can be optimally set.
According to a second aspect of the present invention, there is provided a method for manufacturing a fibrous product comprising:
In this method, for example, the fibrous product includes a substrate sheet and two fiber bundle layers disposed on and locally bonded to two sides of the substrate sheet, respectively, wherein one of the fiber bundle layers is cut by the first cutting blade and the other is cut by the second cutting blade. The fibrous product may be a cleaning article in which the fiber bundle layers thus cut have an effect of collecting dust.
The present invention will be understood more fully from the detailed description given hereinafter and from the accompanying drawings of the preferred embodiment of the present invention, which, however, should not be taken to be limitative to the invention, but are for explanation and understanding only.
In the drawings:
The present invention will be discussed hereinafter in detail in terms of the preferred embodiment according to the present invention with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, to those skilled in the art that the present invention may be practiced without these specific details. In other instance, well-known structures are not shown in detail in order to avoid unnecessary obscurity of the present invention.
The first roll 20 has a rotary shaft 21 and a roll body 22 secured to the rotary shaft 21. The rotary shaft 21 has an axis that is referred to as first roll axis O1. The roll body 22 has a periphery 22a that is a cylindrical surface formed with a radius about the first roll axis O1. On the periphery 22a of the roll body 22, there are disposed several first ribs 41. The individual first ribs 41 project radially from and extend axially on the periphery 22a so that adjacent first ribs 41 are parallel to each other.
Axially opposite side rings 24 and 24 are formed integral with the first roll 20 to have the first ribs 41 located therebetween. The side rings 24 and 24 have peripheries that are referred to as first contact peripheries 24a and 24a. The first contact peripheries 24a and 24a have a larger radius than the periphery 22a.
The second roll 30 has a rotary shaft 31, whose axis is referred to as second roll axis O2. The second roll 30 has a roll body 32, whose periphery 32a is a cylindrical surface formed with a radius about the second roll axis O2. The radius of the periphery 32a of the second roll 30 is identical to the radius of the periphery 22a of the first roll 20. Several second ribs 51 are disposed on the periphery 32a to project radially therefrom. The individual second ribs 51 extend axially so that adjacent second ribs 51 are parallel to each other.
Axially opposite side rings 34 and 34 are formed integral with the second roll 30 to have the second ribs 51 located therebetween. The side rings 34 and 34 have peripheries that are referred to as second contact peripheries 34a and 34a. The second contact peripheries 34a and 34a have a larger radius than the periphery 32a about the second roll axis O2. The radius of the second contact peripheries 34a and 34a is identical to the radius of the first contact peripheries 24a and 24a of the first roll 20.
The first contact peripheries 24a and 24a are pressed against the second contact peripheries 34a and 34a with a force applied to the first roll 20 and the second roll 30 so that the roll axes O1 and O2 approach each other, which results in keeping the first roll axis O1 and the second roll axis O2 in parallel with each other and at a constant distance apart from each other. Thus, the first contact peripheries 24a and 24a of the first roll 20 and the second contact peripheries 34a and 34a of the second roll 30 constitute distance setting means.
A synchronous gear 26 is secured to the rotary shaft 21 of the first roll 20, while a synchronous gear 36 is provided on the rotary shaft 31 of the second roll 30. The synchronous gears 26 and 36 are of the same pitch circle and in meshing engagement with each other. The synchronous gear 36 is composed of two spur gears 36a and 36b, wherein one spur gear 36a is secured to the rotary shaft 31 while the other spur gear 36b is biased circumferentially by means of spring. With the two spur gears 36a and 36b being circumferentially repelled from each other by means of spring and meshing with the synchronous gear 26, the backlash between the synchronous gears 26 and 36 is eliminated.
Between the rotary shaft 21 of the first roll 20 and the synchronous gear 26, a phase adjusting mechanism 27 is further provided. With this phase adjusting mechanism 27, the phase of the rotary shaft 21, which is secured to the roll body 22, in the rotational direction can be adjusted with respect to the phase of the synchronous gear 26 in the rotational direction, and the rotary shaft 21 can be locked to the synchronous gear 26 in the adjusted position. By adjusting the phases between the synchronous gear 26 and the roll body 22 in a state where the synchronous gears 26 and 36 are in meshing engagement with each other, each first rib 41 and its corresponding second rib 51 can be certainly opposed to each other in a plane containing the first and second roll axes O1 and O2, as the first and second rolls 20 and 30 are driven to rotate.
To this end, the first ribs 41 and the second ribs 51 are circumferentially arranged at the same pitch on the first roll 20 and the second roll 30, respectively. The first ribs 41 and the second ribs 51 are of the same length in the axial direction.
As shown in
As shown in the sectional view of
In the first roll 20, both the blade edge 42a of the first cutting blade 42 and the receiving surface 43a of the first abutment 43 are located closer to the roll axis O1 than the first contact peripheries 24a. Also in the second roll 30, both the receiving surface 52a of the second abutment 52 and the blade edge 53a of the second cutting blade 53 are located closer to the roll axis O2 than the second contact peripheries 34a.
A projecting dimension H1 of the blade edge 42a and the receiving surface 43a as measured radially from the periphery 22a is equal to a projecting dimension H2 of the blade edge 53a and the receiving surface 52a as measured radially from the periphery 32a. A distance 6 between the blade edge 42a of the first cutting blade 42 and the receiving surface 52a of the second abutment 52 and between the receiving surface 43a of the first abutment 43 and the blade edge 53a of the second cutting blade 53 is from 0.01 to 0.03 mm.
As the first roll 20 and the second roll 30 are driven to rotate in synchronism with each other, each first rib 41 is momentarily opposed to its corresponding second rib 51 as shown in
The first cutting blade 42 and the second cutting blade 53 are of the same sectional shape and of an included angle θ1 to have an increasing width from the blade edge 42a/53a toward the bottom. The included angle θ1 is about 20 to 70 degrees. On the other hand, the blade edge 42a of the first cutting blade 42 and the blade edge 53a of the second cutting blade 53 are of a width T1 in the range of 0.01 to 0.06 mm. The receiving surface 43a of the first abutment 43 and the receiving surface 52a of the second abutment 52 are of a width T2 which is larger than the width T1 of the blade edge and in the range of 0.08 to 1.0 mm.
The workpiece WA is a fibrous product, in which fiber bundle layers Wb, Wb are disposed on two sides of a substrate sheet Wa. Prior to the cutting process with the rotary cutter 10, the fiber bundle layers Wb, Wb are bonded to the substrate sheet Wa at bond lines Wc which are arranged at regular intervals in the feed direction (MD) of the workpiece WA to extend linearly in a direction (CD) perpendicular to MD.
The substrate sheet Wa is nonwoven fabric comprising thermoplastic fibers, such as spunbonded, meltblown or spunlaced nonwoven fabric. On the other hand, the fiber bundle layer Wb is a bundle of fibers which are unbonded to each other unless otherwise noted. For example, the fiber bundle layer Wb may be a fiber bundle obtained by opening tow, wherein individual fibers extend continuously in MD. The fibers constituting the fiber bundle layer Wb may be sheath/core bicomponent fibers of which the sheath is a low-melting resin such as polyethylene (PE) and the core is polyethylene terephthalate (PET) or polypropylene (PP).
Since both the substrate sheet Wa and the fiber bundle layers Wb contain thermoplastic fibers, the bond lines Wc can be formed by thermal fusion-bonding of the fibers constituting the substrate sheet Wa and the fibers constituting the fiber bundle layers Wb.
When the workpiece WA is fed between the first roll 20 and the second roll 30 that are rotating in synchronism with each other, the workpiece WA is held between the first rib 41 and the second rib 51 at a position between adjacent bond lines Wc.
As shown in
Immediately after the formation of the cut We, furthermore, the workpiece WA is cut from the lower side with the blade edge 53a of the second cutting blade 53 while the upper side is supported by the receiving surface 43a of the first abutment 43. Thus, the fiber bundle layer Wb disposed on the lower side of the substrate sheet Wa is formed with a cut Wf.
Accordingly, the fibrous product is suitable for use as a cleaning article for wiping the floor and the like.
In the fibrous product, furthermore, since each cut We formed in the fiber bundle layer Wb disposed on the upper side of the substrate sheet Wa is very close to its corresponding cut Wf formed in the fiber bundle layer Wb disposed on the lower side of the substrate sheet Wa, these cuts We and Wf look as if they were formed at the same position on the upper and lower sides. Accordingly, the fibrous product looks like having identical brush portions on both the upper and lower sides thereof.
It should be noted that although both the first ribs 41 provided on the first roll 20 and the second ribs 51 provided on the second roll 30 extend axially continuously in the embodiment shown in
The workpieces WA and WB may have nonwoven fabric layers in place of the fiber bundle layers Wb, Wb and these nonwoven fabric layers may be cut with a rotary cutter according to the present invention.
According to the present invention, as has been described hereinabove, cutting of a workpiece halfway through the thickness from both sides thereof can be done at once. Therefore, the rotary cutter according to the present invention is suitable for manufacturing a fibrous product having brush portions of fiber bundle layers on both sides thereof, for example. Furthermore, since thermal fusion-bonding of fibers at cuts is eliminated, a fibrous product having a dust collecting effect due to fluffing can be certainly obtained.
Although the present invention has been illustrated and described with respect to exemplary embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omission and additions may be made therein and thereto, without departing from the spirit and scope of the present invention. Therefore, the present invention should not be understood as limited to the specific embodiment set out above but to include all possible embodiments which can be embodied within a scope encompassed and equivalent thereof with respect to the feature set out in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003-17849 | Jan 2003 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10762881 | Jan 2004 | US |
| Child | 11464617 | Aug 2006 | US |
