Patent Publication Number: US-2021169705-A1

Title: Apparatus for manufacturing absorbent core of disposable worn article, and replacement method for replacing part of the apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to an apparatus for manufacturing an absorbent core of a disposable worn article and a method for replacing a part of the apparatus. 
     BACKGROUND ART 
     As a method for manufacturing an absorbent core of this type, an absorbent body is typically formed by allowing a crushed fiber to be adsorbed on a fiber-stacking depression formed on the outer circumference of a fiber-stacking drum. 
     While the fiber-stacking depression of the drum is formed in a predetermined pattern on the outer circumferential surface of a cylindrical fiber-stacking ring, there is a need to change the pattern in accordance with the size of the worn article, for example. The pattern is formed of segments such as a large number of templates and mesh members arranged along the circumferential direction of the drum. 
     On the other hand, a hood for drawing the fiber onto the drum and a conveyer for introducing a carrier web onto the drum are opposing the outer circumferential surface of the drum. 
     With the apparatus of the first patent document identified below, the fiber-stacking drum is slidable in the axial direction of the rotation shaft so that the drum can be moved away from the hood and the conveyer. This allows for replacement of segments of the drum such as a large number of templates and mesh members, while preventing interference by the hood and the conveyer. 
     CITATION LIST 
     Patent Literature 
     First Patent Document: U.S. Pat. No. 4,995,141 (front page) 
     SUMMARY OF INVENTION 
     With the prior art, however, there is a need to disassemble segments from the drum for replacement. Therefore, for each change of size, there is a need to disassemble a large number of segments and to assemble a large number of other segments. This may lower the facility utilization rate. 
     It is an object of the present invention to provide an apparatus for manufacturing an absorbent core of a disposable worn article and a method for replacing a part of the apparatus, with which it is possible to improve the facility utilization rate. 
     The apparatus of the present invention is an apparatus for manufacturing an absorbent core of a disposable worn article, including:
         a dispenser  1  for dispensing a crushed fiber;   a fiber-stacking drum  2  for stacking the fiber dispensed from the dispenser  1  on an outer circumferential surface  2   f  of the drum  2  while sucking the fiber from the outer circumferential surface  2   f  toward an inside of the drum  2 ; and   a fixed frame  5  for rotatably supporting the fiber-stacking drum  2 , wherein the fiber-stacking drum  2  includes:   a rotation shaft  20  that is rotated;   a wheel  21  attached to one end of the rotation shaft  20 ; and   a cylindrical fiber-stacking ring  22  provided on an outer circumference portion of the wheel  21  for stacking the fiber, wherein:   a suction chamber  6  is fixed to the fixed frame  5 , wherein the suction chamber  6  is arranged on an inner side of the fiber-stacking ring  22  and produces a suction force from an outer circumference toward an inner circumference of the fiber-stacking ring  22 ;   the fiber-stacking drum  2  is supported by the fixed frame  5  so as to be slidable relative to the fixed frame  5  in an axial direction S, in which an axial line L of the rotation shaft  20  extends; and   the wheel  21  is removably attached to the one end of the rotation shaft  20  via a fastener  23 .       

     The method of the present invention is a replacement method for replacing the wheel  21  and the fiber-stacking ring  22  of the fiber-stacking drum  2  of the manufacturing apparatus, the replacement method including the steps of:
         moving the fiber-stacking drum  2  at an operation position P 1  to a replacement position P 2  away from the dispenser  1  by sliding the fiber-stacking drum  2  in a first direction D 1  along the axial line L;   loosening the fastener  23  to remove the wheel  21  and the fiber-stacking ring  22  from the rotation shaft  20 ;   attaching another wheel  21 A and another fiber-stacking ring  22 A to the one end. of the rotation shaft  20 , in place of the wheel  21  and the fiber-stacking ring  22  having been removed; and   sliding the rotation shaft  20 , to which the other wheel  21 A and the other fiber-stacking ring  22 A have been attached, in a second direction D 2 , which is opposite to the first direction D 1 .       

     According to the present invention, the fiber-stacking ring  22  and the wheel  21  can be replaced without disassembling the fiber-stacking ring  22  into segments. Therefore, the replacement operation can be done in a short amount of time. This, as a result, improves the facility utilization rate. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic front view of a manufacturing apparatus showing one example of the present invention. 
         FIG. 2  is a perspective view showing a segment disassembled. 
         FIG. 3  is a schematic back view of the manufacturing apparatus. 
         FIG. 4A  is a vertical cross-sectional view showing a fiber-stacking drum, etc., while in operation, and  FIG. 4B  is a cross-sectional view showing the details of a fiber stacking ring. 
         FIG. 5  is a vertical cross-sectional view showing the fiber stacking drum, etc., during replacement. 
         FIG. 6  is a schematic side view showing a method for removing a fiber stacking ring. 
         FIG. 7  is a schematic side view showing a method for installing a fiber-stacking ring. 
     
    
    
     Note that sliders and bearing inner and outer races are colored in gray for ease of understanding of the drawings. 
     DESCRIPTION OF EMBODIMENTS 
     Preferably, with the apparatus of the present invention, the fiber-stacking drum  2  further includes a cylindrical bearing cylinder  24  for rotatably supporting the rotation shaft  20 ; and
         the fiber-stacking drum  2  including the bearing cylinder  24  is supported by the fixed frame  5  so as to be slidable relative to the fixed frame  5  in the axial direction S.       

     In this case, there is no need for a configuration where the rotation shaft  20  can slide in the axial direction S relative to the bearing cylinder  24 . Therefore, it is possible with the bearing cylinder  24  to reliably axially support the rotation shaft  20 , which rotates at a high speed. 
     More preferably, an output section M 1  of a motor M for rotating the rotation shaft  20  is linked to the other end of the rotation shaft  20 ; and
         the motor M, together with the bearing cylinder  24 , is supported by the fixed frame  5  so as to be slidable relative to the fixed frame  5  in the axial direction S.       

     In this case, the replacement can be done while the motor M remains linked to the rotation shaft  20 . Thus, it is possible to realize a stable rotation of the motor M and the rotation shaft  20 , which rotate at a high speed. 
     More preferably, the manufacturing apparatus further includes:
         a slider  25  fixed to the bearing cylinder  24 ; and   a linear guide  41  for guiding the slider  25  in a direction parallel to the axial direction S.       

     In this case, it is possible to reliably and easily slide the fiber-stacking drum  2  in the axial direction S. 
     More preferably, the manufacturing apparatus further includes an actuator  7  for sliding the slider  25  along the linear guide  41 . 
     In this case, it is possible to slide the fiber-stacking drum  2  in the axial direction S by operating the actuator  7 . 
     Any feature illustrated and/or depicted in conjunction with one of the aforementioned aspects or the following embodiments may be used in the same or similar form in one or more of the other aspects or other embodiments, and/or may be used in combination with, or in place of, any feature of the other aspects or embodiments. 
     EMBODIMENTS 
     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. 
     One embodiment of the present invention will now be described with reference to the drawings.
         An absorbent core to be manufactured by the present manufacturing apparatus is used as the core of incontinence pads as well as disposable pants and diapers, for example, and has an hourglass-like shape, for example.       

     As shown in  FIG. 1 , the present manufacturing apparatus includes a dispenser  1 , a fiber-stacking drum  2 , a suction chamber  6 , a guide roll  8  and a conveyer  9 . 
     The dispenser  1  includes a dome-shaped case  10  and a defibrator (a defibration machine)  11 . The defibrator  11  defibrates (crushes) a pulp dispensed from upstream into a fibrous material to produce a fluff pulp (fiber). The fluff pulp fills up the case  10 , and with the suction chamber  6  of the fiber-stacking drum  2  set at a negative pressure, the fluff pulp is stacked onto the fiber-stacking ring  22  of the fiber-stacking drum  2 . Such defibration and fiber-stacking are techniques well known in the art, and are disclosed in JP2009-112438A, for example.
         Note that a granular material of a polymer compound having a high absorption capacity called “SAP” (super absorbent polymer particles) may be added as a material of the absorbent core.       

     The fiber-stacking ring  22  of  FIG. 4A  is generally cylindrical and includes a plurality of, or a large number of, segments  3  arranged along the circumferential direction R of  FIG. 1 .
         For the sake of illustration,  FIG. 2  shows components of one segment  3  disassembled and arranged in a flat layout. Each segment  3  includes a template  31 , a mesh member  32  and a lattice member  33 , etc.       

     A large number of, or countless, through holes  32   a  are formed in the mesh member  32  by performing an etching process well known in the art on a thin metal plate. The through holes  32   a  are sized so that they allow air therethrough but can receive the fiber and SAP. For example, a pair of templates  31  are provided and arranged on the outer circumferential surface side of the mesh member  32 , forming a fiber-stacking depression  30 .
         Note that for the sake of illustration, meshes of the mesh member  32  are shown enlarged and only some of them are shown.       

     The pair of templates  31  and  31  are spaced apart from each other in the width direction D, wherein the space therebetween forms the fiber-stacking depression  30 . The fiber stacked in the fiber-stacking depression  30  becomes an absorbent core of an individual worn article. 
     That is, the fiber-stacking drum  2  of  FIG. 1 , while continuously rotating in the circumferential direction R, sucks the fiber dispensed from the dispenser  1  toward the suction chamber  6  on the inner side from an outer circumferential surface  2   f  ( FIG. 4A ) of the fiber-stacking ring  22 , thereby continuously stacking the fiber onto the outer circumferential surface  2   f  of a predetermined fiber-stacking depression  30  of  FIG. 4B . That is, the fiber is stacked on the outer circumferential surface  2   f  of the cylindrical fiber-stacking ring  22  defining the fiber-stacking depression  30 . 
     The lattice member  33  of  FIG. 2  is formed of frames  33   a  extending in the width direction. D and the circumferential direction R so as not to inhibit suction of the fiber. The lattice member  33  is in contact with the mesh member  32  and supports the inner circumferential surface of the mesh member  32 , which is vulnerable to an external force. 
     As shown in  FIG. 3 , the suction chamber  6  is arranged over a predetermined section of the fiber-stacking drum  2  in the circumferential direction R, and is connected to a negative pressure source (not shown) via a plurality of ducts  61  so that the inside of the chamber is at a negative pressure. 
     As shown in  FIG. 4A , the suction chamber  6  is arranged close to the inner circumference side of the fiber-stacking ring  22  of the fiber-stacking drum  2 . That is, the suction chamber  6  is fixed to the fixed frame  5 , wherein the suction chamber  6  is in contact with the inner circumference of (arranged on the inner side of) the fiber-stacking ring  22  and produces a suction force exerting from the outer circumference of the fiber-stacking ring  22  toward the inner circumference of the fiber-stacking ring  22 . For example, this suction chamber  6  may be fixed to the fixed frame  5  via the ducts  61 . 
     The fixed frame  5  is a vertical place well known in the art that supports the various machine parts of the apparatus for manufacturing a disposable worn article. As will be described below, the fixed frame  5  rotatably supports the fiber-stacking drum  2 . 
     As shown in  FIG. 4A , the fiber-stacking drum  2  includes a rotation shaft  20  that is rotated, a wheel  21  attached to the distal end (one end) of the rotation shaft  20 , and the cylindrical fiber-stacking ring  22 . 
     The fiber-stacking ring  22  is provided on the outer circumference portion along the edge of the wheel  21  for stacking the fiber. The wheel  21  is removably attached to the distal end (one end) of the rotation shaft  20  via a fastener  23 . For example, the fastener  23  may include a plurality of bolts, which pass through the wheel  21  and are screwed into the distal end of the rotation shaft  20 . 
     As shown in  FIG. 4A  and  FIG. 4B , the fiber-stacking ring  22  includes a pair of annular frame rings  29 . A large number of segments  3  are arranged next to each other in the circumferential direction R as shown in  FIG. 1  along the annular frame rings  29 . 
     As shown in  FIG. 4B , the pair of frame rings  29 ,  29  are linked to each other in the axial direction S via the lattice member  33 . The template  31 , the mesh member  32  and the lattice member  33  of each segment  3  are fixed between the pair of frame rings  29 ,  29  in the axial direction S. 
     As shown in  FIG. 4A , the fiber-stacking drum  2  further includes a cylindrical bearing cylinder (a cylindrical bearing sleeve)  24  that rotatably supports the rotation shaft  20 . An output section of a servomotor M that rotates the rotation shaft  20  is linked to the proximal end (the other end) of the rotation shaft  20  via a decelerator G and a coupling J. The motor M is fixed to the bearing cylinder  24  via the decelerator G. 
     A link portion  26  is attached to the bearing cylinder  24 , and a case  28  extending in the axial direction S is attached to one end of the link portion  26 . A portion of the rotation shaft  20  and the coupling J are accommodated inside the case  28 , and the opening of the case  28  is covered (lidded) by the decelerator G. That is, the rotation shaft  20  and the coupling J are accommodated in the space that is formed by the bearing cylinder  24 , the case  28  and the decelerator G, and it is therefore possible to prevent the crushed fluff pulp (fiber) from being stuck on the rotation shaft  20 , etc. 
     The bearing cylinder  24  is fixed to a slider  25 . That is, the slider  25  is attached to the bearing cylinder  24  via the link portion  26  and a moving plate  42 . The slider  25  is guided by a linear guide  41  in the direction parallel to the axial direction S. The linear guide  41  is fixed to the fixed frame  5  via a base  4 . Note that the slider  25  is colored in gray in the figures. 
     An actuator  7  such as an air cylinder is attached to the base  4 . That is, the actuator  7  is fixed to the fixed frame  5  via the base  4 . In other words, the actuator  7  is attached to a non-rotating portion of the present manufacturing apparatus. 
     The actuator  7  slides the motor M, the bearing cylinder  24  and the fiber-stacking drum  2  in the axial direction S via the slider  25 , the moving plate  42  and the link portion  26 . 
     For example, the moving plate  42  is fixed to the distal end of a rod  71  of an air cylinder  7 , and the fiber-stacking drum  2  slides between the operation position P 1  of  FIG. 4A  and the replacement position P 2  of  FIG. 5 . 
     Thus, the fiber-stacking drum  2 , together with the motor M and the bearing cylinder  24 , is supported by the fixed frame  5  so as to be slidable relative to the fixed frame  5  in the axial direction S, in which the axial line L of the rotation shaft  20  extends. 
     In the present embodiment, since the axial line L of the rotation shaft  20  and the axial line L of the motor M are arranged on the same axial line, the bearing cylinder  24 , the motor M and the fiber-stacking drum  2  can easily slide in the axial direction S. 
     Next, a method for manufacturing an absorbent core will be described briefly.
         While manufacturing an absorbent core, the fiber-stacking drum  2  is set to the operation position P 1  of  FIG. 4A .       

     A carrier web W is continuously introduced from the guide roll  8  onto the fiber-stacking drum  2  of  FIG. 1 . On the other hand, while the fiber-stacking drum  2  continuously rotates in the circumferential direction R, the fiber dispensed from the dispenser  1  is sucked by the suction chamber  6  toward the inside from the outer circumferential surface  2   f  of the fiber-stacking drum  2  (the outer circumferential surface  2   f  of the fiber-stacking depression  30 ). Thus, the fiber is continuously stacked on the outer circumferential surface  2   f  ( FIG. 4B ) of the fiber-stacking depression  30 , thereby producing a continuous core C. 
     In  FIG. 1 , as well known in the art, the carrier web W dispensed from the guide roll  8  is laid over the stacked continuous core C. Then, the continuous core C and the carrier web W are rolled out of the fiber-stacking drum  2  as an integral material. Then, as well known in the art, it may be severed into absorbent cores of individual worn articles on the downstream side (not shown). Instead of producing the continuous core C, individual absorbent cores may be produced by fiber-stacking on the fiber-stacking drum  2 . 
     Next, a replacement method for replacing the wheel  21  and the fiber-stacking ring  22  of the fiber-stacking drum  2  of the manufacturing apparatus. 
     In order to replace, first, the operator slides the fiber-stacking drum  2  of  FIG. 4A  from the operation position P 1  to the replacement position P 2  of  FIG. 5 . That is, the wheel  21  and the fiber-stacking ring  22  are moved from the operation position P 1  to the replacement position P 2  of  FIG. 5  by sliding the motor M, the bearing cylinder  24  and the fiber-stacking drum  2  in the first direction D 1  along the axial line L by protruding the rod  71  of the air cylinder  7  of  FIG. 4A . Thus, the wheel  21  and the fiber-stacking ring  22  move to a position away from the dispenser  1  ( FIG. 1 ). 
     Note that the first direction D 1  means the direction from the proximal end (the proximal end of the rotation shaft  20 ) to which the output section M 1  of the motor M is linked toward one end (one end of the rotation shaft  20 ) to which the wheel  21  is attached. 
     Then, the operator loosens the fastener  23  of  FIG. 5  and removes the wheel  21  and the fiber-stacking ring  22  from the rotation shaft  20 . As shown in  FIG. 6 , the wheel  21  and the fiber-stacking ring  22  having been removed are moved onto a first platform truck  101 . 
     The operator moves another wheel (a substitute wheel)  21 A and another fiber-stacking ring (a substitute fiber-stacking ring)  22 A of  FIG. 7  from a second platform truck  102  and attaches them to the distal end of the rotation shaft;  20 , in place of the wheel  21  and the fiber-stacking ring  22  of  FIG. 6  having been removed. The segments  3  on the other fiber-stacking ring  22 A may be of a different pattern from the segments of the removed fiber-stacking ring  22 . 
     Thereafter, through an opposite procedure from the removal, the operator actuates the actuator  7  to slide the rotation shaft  20 , to which the other wheel  21 A and the other fiber-stacking ring  22 A have been attached, together with the motor M and the bearing cylinder  24  of  FIG. 5 , in the second direction D 2 , which is opposite to the first direction D 1 . 
     Thus, replacement can be done quickly when manufacturing worn articles of different sizes, for example. 
     While one embodiment has 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, the replacement of the wheel and the fiber-stacking ring may be done for a change in the shape of the absorbent core, instead of a change in size.   When replacing the fiber-stacking ring, only segments may be replaced without replacing the wheel.   A plurality of through holes may be provided in the wheel for reducing the weight thereof.   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 an apparatus for manufacturing an absorbent core of a disposable worn article, 
     REFERENCE SIGNS LIST 
     
         
           1  Dispenser, 
           10 : Case, 
           11 : Defibrator 
           2 : Fiber-stacking drum, 
           2   f : Outer circumferential surface, 
           20 : Rotation shaft, 
           21 : Wheel 
           22 : Fiber-stacking ring, 
           29 : Frame ring 
           21 A: Another wheel, 
           22 A: Another fiber-stacking ring 
           23 : Fastener, 
           24 : Bearing cylinder, 
           25 : Slider, 
           26 : Link portion, 
           28 : Case 
           3 : Segment, 
           30 : Fiber-stacking depression, 
           31 : Template, 
           32 : Mesh member 
           32   f:  Inner circumferential surface side, 
           33 : Lattice member, 
           33   a : Frame 
           4 : Base, 
           41 : Linear guide, 
           42 : Moving plate 
           5 : Fixed frame, 
           6 : Suction chamber, 
           61 : Duct 
           7 : Actuator, 
           71 : Rod, 
           8 : Guide roll, 
           9 : Conveyer 
           101 ,  102 : Platform truck. 
         C: Continuous core, 
         L: Axial line, 
         S: Axial direction 
         M: Motor, 
         M 1 : Output section, 
         G: Decelerator, 
         J: Coupling 
         P 1 : Operation position, 
         P 2 : Replacement position. 
         R: Circumferential direction, 
         D: Width direction, 
         D 1 : First direction, 
         D 2 : Second direction 
         W: Carrier web