Patent Publication Number: US-9414647-B2

Title: Upper die for button attachment

Description:
This application is a divisional application of U.S. patent application Ser. No. 13/498,163 which is a national stage application of PCT/JP2010/061904 which claims priority to PCT Application No. PCT/JP2009/066957, all of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The subject invention relates to a button, and an upper die for button attachment. 
     BACKGROUND ART 
     When a button is attached to a cloth, generally, the button is positioned over a horizontally-arranged cloth, a button-fixing member is supported by a lower die under the cloth, and a shaft of the button-fixing member pierce the cloth. Next, after the shaft has passed through an attachment hole of the button, an upper die coupled to a pressing machine is moved down towards the lower die, thereby the shaft being swaged through press-deformation by a bottom of the upper die. Japanese Examined Patent Laid-Open No. 61-43443 and Japanese Examined Utility Model Laid-Open No. 4-2979 disclose examples of conventional upper dies. 
     In the conventional upper dies, however, when the shaft of the button-fixing member is press-deformed for button-attachment, the shaft is deformed to radially outwardly expand in an entire circumferential direction. Therefore, if the cloth is thick, the outward radial expansion of the shaft fails, and there may be cases where enough button attachment power and button strength are not secured. On the other hand, if the cloth is thin, there may be a case where the shaft extends radially outwardly more than required to cause a surplus portion, resulting in that formability may be degraded. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] Japanese Examined Patent Laid-Open No. 61-43443 
     [PTL 2] Japanese Examined Utility Model Laid-Open No. 4-2979 
     SUMMARY OF INVENTION 
     Technical Problem 
     The subject invention provides a button with better formability where enough button attachment power and button strength are secured regardless of thickness of the cloth and so on, and an upper die for button attachment that is for producing said button. 
     Solution to Problem 
     In order to solve the above problem, one aspect of the invention provides a button including: a button body that is placed over a first main surface of a sheet having the first main surface and a second main surface opposing to the first main surface, the button body having a hole over the first main surface; and a fixing member including a base that is placed over the second main surface, and a shaft that projects from the base and passes through the hole from the second main surface towards the first main surface side, in which a distal portion of the shaft includes: a plate-like base portion provided over the button body and covering the hole; and a plurality of ribs integrally formed with the base portion and onto a surface of the base portion, and radially extending from a center to a circumference of the base portion. 
     One embodiment of a button according to the subject invention further includes a circular rib that is formed on the surface of the base portion and is integrally formed with the base portion and the rib, the circular rib being provided concentrically with an outer edge of the base portion. 
     Another aspect of the subject invention provides a button including: a button body that is placed over a first main surface of a sheet having the first main surface and a second main surface opposing to the first main surface, the button body having a hole over the first main surface; and a fixing member including a base placed over the second main surface, and a shaft that projects from the base and passes through the hole from the second main surface towards the first main surface side, in which a distal portion of the shaft includes: a plate-like base portion provided over the button body and covering the hole; and a plurality of ribs integrally formed with the base portion and radially projecting from an outer edge of the base portion. 
     In one embodiment of a button according to the subject invention, the thickness of the plurality of ribs is thinner than the thickness of the base portion. 
     Yet another aspect of the subject invention provides an upper die for button attachment for swaging an distal portion of a shaft that projects towards a first main surface side and passes through a hole towards the first main surface side, in which a button body with a hole is provided over the first main surface of a sheet having the first main surface and a second main surface opposing to the first main surface, and in which a fixing member having a base and a shaft projecting from the base is positioned over the second main surfaces, the upper die for button attachment including: an effect bottom that contacts with the shaft for swaging the shaft, and in which the effect bottom includes: a plurality of peripheral recesses provided on a rim that defines an outer edge of the effect bottom; an expansion allowing portion for allowing an expansion of the shaft towards an outer side in the radial direction during swage, the expansion allowing portion being provided at inner side of the rim; and a plurality of peripheral projections projecting in a longitudinal direction of the upper die for attachment than the peripheral recess at the rim, the plurality of peripheral projections being provided in a mutually separated manner in a circumferential direction of the rim. 
     In one embodiment of the upper die for button attachment according to the subject invention, the peripheral projection further projects towards the expansion allowing portion from the rim. 
     In one embodiment of the upper die for button attachment according to the subject invention, the thickness of the peripheral projection is formed to be gradually thicker towards the expansion allowing portion from the rim. 
     In one embodiment of the upper die for button attachment according to the subject invention, the expansion allowing portion is a recessed groove that expands towards the rim from a center of the effect bottom. 
     In one embodiment of the upper die for button attachment according to the subject invention, the expansion allowing portion includes: a central recess upwardly diverging at the center of the effect bottom; a circular recess upwardly diverging in a circular manner at a periphery of the central recess; a circular projection relatively downwardly diverging at an interface between the central recess and the circular recess. 
     In one embodiment of the upper die for button attachment according to the subject invention, the expansion allowing portion includes: an expansion effect surface that presses the shaft during swage; and a sidewall that is provided along a circumference of the expansion effect surface. 
     In one embodiment of the upper die for button attachment according to the subject invention, the expansion effect surface is movable up and down along the sidewall. 
     Advantageous Effects of Invention 
     According to the subject invention, there are provided a button with better formability where enough button attachment power and button strength are secured regardless of thickness of the cloth and so on, and an upper die for button attachment to produce that button. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective cutaway view showing a button according to a first embodiment of the subject invention 
         FIG. 2  is a front view of the button according to the first embodiment. 
         FIG. 3  is a sectional view of the button according to the first embodiment. 
         FIG. 4  is a sectional view showing an alternative example of the button according to the first embodiment. 
         FIG. 5  is a perspective view showing an upper die for swaging the shaft of the button to deform according to the first embodiment. 
         FIG. 6  is a front view of the upper die shown in  FIG. 5 . 
         FIG. 7  is an assembling process view (No. 1) of the button according to the first embodiment. 
         FIG. 8  is an assembling process view (No. 2) of the button according to the first embodiment. 
         FIG. 9  is an assembling process view (No. 3) of the button according to the first embodiment. 
         FIG. 10  is an assembling process view (No. 4) of the button according to the first embodiment. 
         FIG. 11  is a perspective cutaway view showing a button according to a second embodiment of the subject invention. 
         FIG. 12  is a front view of the button according to the second embodiment. 
         FIG. 13  is a sectional view of the button according to the second embodiment. 
         FIG. 14  is a perspective view showing an upper die for swaging the shaft of the button to deform according to the second embodiment. 
         FIG. 15  is a front view of the upper die shown in  FIG. 14 . 
         FIG. 16  is an assembling process view (No. 1) of the button according to the second embodiment. 
         FIG. 17  is an assembling process view (No. 2) of the button according to the second embodiment. 
         FIG. 18  is an assembling process view (No. 3) of the button according to the second embodiment. 
         FIG. 19  is a partially expanded view of the button according to an alternative example of the first embodiment. 
         FIG. 20  is a perspective view of the upper die according to an alternative example of the first embodiment. 
         FIG. 21  is a partially expanded view of the button according to an alternative example of the second embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the subject invention will be explained with reference to drawings. In the disclosures of the drawings below, the same or like portions have been designated by the same or like reference signs. The embodiments below exemplify the apparatus and method for embodying the technical idea of the subject invention, and the technical idea of the subject invention should not be limited to structures, arrangements, materials and so on of the components discussed below. 
     The First Embodiment 
     Button 
     As shown in  FIGS. 1 to 3 , the button according to a first embodiment of the invention has a button body  20  having a hole  24 A and placed over a first main surface  1   a  of a sheet  1  which has the first main surface  1   a  and a second main surface  1   b  opposing to the first main surface  1   a , and a fixing member  30  having a base  31  placed over the second main surface  1   b  and a shaft  32  that projects from the base  31  and protrudes to the first main surface  1   a  side after passing through the hole  24 A from the second main surface  1   b.    
       FIGS. 1 to 3  show an example where a female snap button  20 A is used as the bottom body  20 . The female snap button  20 A includes a cylinder side  22 A and a disk-like bottom  23 A which define a coupling recess  21 A for receiving a coupling-projection of a male snap, not shown in figure, in a removable manner. The hole  24 A (See  FIG. 3 ) extending through the bottom  23 A is provided at the center of the bottom  23 A, and an distal portion  32   a  of the shaft  32  protrudes from the hole  24 A to the first main surface  1   a  side. 
     The fixing member  30  is normally made of resin, and examples of which are polyamide (PA), polyacetal (POM), polycarbonate (PC), denatured polyphenylene ether (m-PPE), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), glass-fiber-reinforced polyethylene terephthalate (GF-PET), cyclic polyolefin (COP) and so on. It may be made of metal such as a brass and an aluminum alloy and so on. As shown in  FIG. 7 , the base  31  is shaped like a disk, and the shaft  32  before being swaged is shaped to upwardly extend from the center of the base  31  and to become thinner towards its tip. 
     As shown in  FIG. 1 , the distal portion  32   a  of the shaft  32  has a plate-like base portion  321   a  that is placed on the button body  20  to cover the hole  24 A and a part of the bottom  23 A, and ribs  322   a  that radially extends from the center to the circumference of the base portion  321   a  and formed integrally with the base portion  321   a  and onto the surface of the base portion  321   a . The planar shape of the base portion  321   a  should not be limited, and various shapes, such as an oval, a rectangle, and a polygon may be selected. As shown in  FIG. 2 , the planar shape of the base  312   a  is formed to be circular congruently with the outer shape of the female snap button  20 A, thereby buttons with superior fancy appearance being obtained. The thickness of the base portion  321   a  can be varied in accordance with the thickness of the sheet, which is a fixing object. As shown in  FIG. 2 , the ribs  322   a  are formed at 6 locations by 60 degree interval in the circumferential direction of the base portion  321   a . The number of ribs  322   a  should not be limited to 6 locations and, for example it may be formed at 8 locations by 45 degree interval. Alternatively, it may be formed at 5 locations by approximately 72 degree interval. As shown in  FIG. 1 , the thickness of the rib  322   a  is formed to be gradually thinner radially outwardly from the center of the base portion  321   a . At the central surface portion of the base portion  321   a , there is provided a circular rib  323   a  that is connected to an end of the rib  322   a  and is provided concentrically with the outer edge of the base portion  321   a . The circular rib  323   a  is integrally formed to the base portion  321   a  and the rib  322   a.    
     The shape of the button body  20  should not be limited to the example shown in  FIGS. 1 to 3 , and other various shapes may be selected. For example, as shown in  FIG. 4 , the male snap button  20 B may be selected as the button body  20 . The male snap button  20 B includes a cylinder side  22 B and a disk-like bottom  23 B which define a coupling-projection  21 B to be received by a coupling recess of a female snap, not shown in figure, in a removable manner. The hole  24 B is provided at the center of the bottom  23 B, and the distal portion  32   a  of the shaft  32  protrudes from the hole  24 B. 
     As for the sheet  1 , it should not be particularly limited insofar as it is a sheet-like member such as a thin plate of leather, paper, plastic, or rubber and so on, other than the cloth. Further, in the subject invention, the surface at a side onto which the button body  20  is attached is defined as the first main surface  1   a , and the surface at a side onto which the fixing member  30  is attached is defined as the second main surface  1   b , however, it should be appreciated that the surface at a side onto which button body  20  is attached may be the second main surface  1   b  and the surface at a side onto which the fixing member  30  is attached may be the first main surface  1   a.    
     According to the button of the first embodiment, the ribs  322   a , which are integral with the base portion  321   a , are provided in the coupling recess  21 A of the button body  20 . The ribs  322   a  are radially provided on the base portion  321   a , thereby the entire surface of the base portion  321   a  being strengthened. As a result of this, it is possible to supply a button which has enough button attachment power and button strength and in which damages are suppressed even in a case where cloth thickness is thick. Further, formability and fancy appearance are improved because the ribs  322   a  are radially extending on the base portion  321   a.    
     Upper Die for Button Attachment 
     As shown in  FIG. 5 , an upper die for button attachment  10 A (hereinafter simply referred to as an “upper die  10 A”) according to the first embodiment has an effect bottom  11 A that contacts with a tip  32   d  of the shaft  32  for swaging the shaft  32  (See  FIG. 7 ). The effect bottom  11 A has peripheral recesses  15 A provided on a rim  12 A defining an outer edge of the effect bottom  11 A, an expansion allowing portion  13 A provided at inner side of the rim  12 A (central of the effect bottom  11 A), and peripheral projections  14 A provided in a mutually separated manner in the circumferential direction of the rim  12 A. 
     The expansion allowing portion  13 A is positioned at the inner side of the rim  12 A, and is a recessed groove (space) expanding towards the rim  12 A from the center of the effect bottom  11 A. The expansion allowing portion  13 A contacts with the tip  32   d  (See  FIG. 7 ) of the shaft  32  and receives the deformation of the tip  32   d  of the shaft  32  during swage, and serves as an expansion guiding region for causing the tip  32   d  of the shaft  32  to greatly expand radially outwardly. The expansion allowing portion  13 A has a central recess  131   a  upwardly diverging at the center of the effect bottom  11 A, a circular recess  133   a  upwardly diverging around the central recess  131   a , and a circular protrusion  132   a  relatively downwardly diverging at the interface between the central recess  131   a  and the circular recess  133   a.    
     As shown in  FIG. 7 , the central recess  131   a  and the circular recess  133   a  are both upwardly diverging in the effect bottom  11 A, and their depths are substantially equal. The cross-sectional view of the central recess  131   a  is reversed U-shape, and the cross-sectional view (along one of the radius) of the circular recess  133   a  is an obtuse isosceles triangle shape, and its apical angle is collapsed to flatten the bottom end  1333  of the circular recess  133   a . Further, the distal end of the circular protrusion  132   a  is slightly rounded. 
     As shown in  FIG. 5 , the peripheral recess  15 A and the peripheral projection  14 A are alternatingly arranged side by side along the rim  12 A in the circumferential direction of the rim  12 A. The number of the peripheral recess  15 A and the peripheral projection  14 A should not be limited in particular. The peripheral projections  14 A are provided to protrude from the peripheral recesses  15 A in the longitudinal direction of the upper die  10 A (arrow direction shown in  FIG. 5 ). The peripheral projections  14 A further extends from the rim  12 A towards the expansion allowing portion  13 A (the center of the effect bottom  11 A). The peripheral recess  15 A serves as a portion that allows the outward radial expansion of the shaft  32  when the shaft  32  is swaged. The peripheral projection  14 A serves as a portion that limits the outward radial expansion of the shaft  32  at the time of swage. 
     As shown in  FIG. 6 , a bottom  14   a  of the peripheral protrusion  14 A has a shape (substantially triangle shape) which gradually narrows towards the center of the effect bottom  11 A in its width in the circumferential direction, and a top  14   b  positioned at the center side of the effect bottom  11 A is rounded. In the example shown in  FIG. 6 , the bottom  14   a  of the peripheral projection  14 A is provided in a horizontal plane orthogonal to the longitudinal direction of the upper die, but this should not be a ground for limitation. As shown in  FIG. 5 , the thickness (the length parallel to the longitudinal direction of the upper die  10 A) of the peripheral projections  14 A is formed to be gradually thicker from the rim  12 A towards the expansion allowing portion  13 A (the center of the effect bottom  11 A). 
     The peripheral recess  15 A is a strap-like bottom surface along the rim  12 A. This bottom surface may be a slope being inclined upwardly towards the center of the effect bottom  11 A, or may be a flat being parallel to the bottom surface of the peripheral projection  14 A. 
     Attachment Process 
     Next, an attachment process for attaching the female snap button  20 A onto the sheet  1  using the upper die for button attachment  10 A of  FIG. 5  will be described.  FIG. 7  shows an arrangement of the main components in an up and down direction (axial direction) just before the female snap button  20 A being attached to the cloth that is one example of the sheet  1  and, from above, the upper die for button attachment  10 A, the female snap button  20 A, the sheet  1 , the fixing member  30 , and the lower die  40  for supporting the fixing member  30  are disclosed. The lower die  40  has, on its front surface, a support recess  41  capable of receiving the base  31  of the fixing member  30 . When the fixing member  30  is placed in the support recess  41 , an axis of the shaft  32  of the fixing member is aligned with the axis of the upper die  10 A. 
     At an initial attachment stage in  FIG. 8 , the shaft  32  of the fixing member  30 , after pierced the sheet  1 , protrudes to the coupling recess  21 A side of the female snap button  20 A above after passing through the hole  24 A of the female snap button  20 A. Next, as shown in  FIG. 9 , the upper die  10 A is moved down (there may be a case where the lower die  40  is moved up) to receive the tip  32   d  of the shaft  32  of the fixing member  30  by the central recess  131   a  of the effect bottom  11 A. This allows centering being automatically performed. Following to this, the upper die  10 A is further moved down, and the circular protrusion  132   a  of the effect bottom  11 A bites into the shaft  32 . Subsequent to this initial event, the effect bottom  11 A press-deforms the shaft  32  against the upper surface (bottom surface)  23 A′ of the bottom  23 A of the female snap button  20 A as shown in  FIG. 10 , thereby the female snap button  20 A being fixed onto the sheet  1 . While this shaft  32  is swaged, the shaft  32  overreaches the hole  24 A and expands radially outwardly on the bottom  23 A′ of the female snap button  20 A. The outwardly expanded allowance portion is received and press-deformed by the circular recess  133   a . This outward radial expansion of the shaft  32  bumps into the 6 peripheral projections  14 A shown in  FIG. 5 , and is greatly expanded radially outwardly at the circular recess  133   a  and the peripheral recess  15 A between the two peripheral projections  14 A sitting side by side in the circumferential direction. 
     As shown in  FIG. 5 , the peripheral projections  14 A are formed to be gradually thinner in its thickness from the center of the effect bottom  11 A towards the rim  12 A, and the top  14   b  is rounded as shown in  FIG. 6 . Owing to this, the existence of the peripheral projections  14 A hardly serves to prevent the outward and radial deformation of the shaft  32 . The shape of the end portion  32   a  of the shaft  32  matches with the shape of bumps and dips of the effect bottom  11 A. Thus, the distal portion  32   a  of the swaged shaft is formed to have a radially-outwardly-greatly-expanded portion (rib  322   a ) corresponding to the recess  133   a , and a less-expanded portion (not shown) corresponding to the peripheral projections  14 A which are alternatingly arranged in the circumferential direction. Finally, its appearance is formed to be a radial shape (petal shape) with 6 ribs as shown in  FIG. 1 . 
     As such, by the attachment method using the upper die for button attachment according to the first embodiment, for example, even in a case where the sheet  1  is thick, the shaft  32  of the fixing member  30  is gathered between the peripheral projections  14 A and is deformed radially and outwardly to a relatively great extent, and thus the required button attachment power is secured. Even in a case where the sheet  1  is thin, the outward and radial deformation of the shaft  32  is decentralized in the circumferential direction and less power is required for swage, and therefore the load of the pressing machine is prevented to be greater. 
     Second Embodiment 
     Button 
     The button according to a second embodiment of the subject invention, as shown in  FIGS. 11 to 13 , has the button body  20 A having the hole  24 A on the first main surface  1   a  and placed over the first main surface  1   a  of the sheet  1  that has the first main surface  1   a  and the second main surface  1   b  opposing to the first main surface  1   a , and the fixing member  30  having the base  31  that is placed over the second main surface  16  and the shaft  32  that projects from the base  31  and protrudes to the first main surface  1   a  side after passing through the hole  24 A from the second main surface  1   b.    
       FIGS. 11 to 13  show an example where a female snap button  20 A is used as the button body  20 . The female snap button  20 A includes the cylinder side  22 A and the disk-like bottom  23 A which define the coupling recess  21 A for receiving a coupling-projection of a male snap in a removable manner. The hole  24 A (See  FIG. 16 ) extending through the bottom  23 A is provided at the center of the bottom  23 A, and the distal portion  32   b  (See  FIG. 13 ) of the shaft  32  protrudes from the hole  24 A to the first main surface  1   a  side. 
     The fixing member  30  is normally made of a resin, and examples of which are polyamide (PA), polyacetal (POM), polycarbonate (PC), denatured polyphenylene ether (m-PPE), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), glass-fiber-reinforced polyethylene terephthalate (GF-PET), cyclic polyolefin (COP) and so on. It may be made of metal such as a brass and an aluminum alloy and so on. As shown in  FIG. 16 , the base  31  is shaped like a disk, and the shaft  32  before being swaged is shaped to extend upwardly from the center of the base  31  and to become narrower towards its tip. 
     As shown in  FIG. 11 , the distal portion  32   b  of the shaft  32  has a plate-like base portion  321   b  that is placed on the button body  20  to cover the hole  24 A (not shown in Figure) and a part of the bottom  23 A, and ribs  322   a  that radially project from an outer edge of the base portion  321   a  and are integrally formed to the base portion  321   a  at the outer edge of the base portion  321   b . The planar shape of the base portion  321   b  should not be limited in particular, and various shapes, such as an oval, a rectangle, and a polygon may be selected. As shown in  FIG. 12 , the shape of the base portion  321   b  is formed to be circular, thereby buttons with superior fancy appearance being obtained. The thickness of the base portion  321   a  can be varied in accordance with the thickness of the sheet which is a fixing object. The ribs  322   b  have a semi-circular or semi-oval shape as of its planar shape, and are respectively formed at 6 locations by 60 degree interval in the circumferential direction at the outer edge of the base portion  321   b . The number of ribs  322   b  should not be limited to 6 locations and, for example, it may be formed at 8 locations by 45 degree interval. Alternatively, it may be formed at 5 locations by approximately 72 degree interval. The rib  322   b  is formed to be thinner than the base portion  321   b  in its thickness (sheet thickness direction). Although not illustrated in figures, it should be appreciated that the male snap button may be selected as the button body  20  in replace to the female snap button  20 A. The sheet  1  should not be particularly limited insofar as it is a sheet-like member such as a thin plate of leather, paper, plastic, or rubber and so on, other than the cloth. 
     According to the button of the second embodiment, substantially planner plate-like base portion  321   b  and the ribs  322   b  being integral with the base portion  321   b  are provided in the coupling recess  21 A of the button body  20 . The button body and the fixing member  30  are closely fixed by the base portion  321   b  and ribs  322   b , and therefore, even in a case where the cloth thickness is thick, damages are suppressed and a button having enough button attachment power and button strength may be obtained. Furthermore, formability may be improved, and fancy appearance may improve. 
     Upper Die for Button Attachment 
     As shown in  FIG. 14 , an upper die for button attachment  10 B according to the second embodiment (hereinafter simply referred to as an “upper die  10 B”) has an effect bottom  11 B that contacts with a tip  32   d  (See  FIG. 16 ) of the shaft  32  for swaging the shaft  32 . The effect bottom  11 B has peripheral protrusions  14 B provided along the rim  12 B defining an outer edge of the effect bottom  11 B, peripheral recesses  15 B respectively provided along the rim  12 B in a mutually separated manner, and expansion allowing portion  13 B that allows the outward radial expansion of the shaft  32  and is provided at inner side of the rim  12 B (central of the effect bottom  11 B). 
     The expansion allowing portion  13 B is positioned at inner side of the rim  12 B, and is a recessed groove (space) extending towards the rim  12 B from the center of the effect bottom  11 B. The expansion allowing portion  13 B serves as an expansion guiding region for causing the shaft  32  to greatly expand radially outwardly. The expansion allowing portion  13 B has an expansion effect surface  131   b  that is a flat press-surface for contacting with the shaft  32  and a sidewall  132   b  formed along the circumference of the expansion effect surface  131   b . In the example shown in  FIG. 16 , the upper die  10 B is configured by a pillar-like member  100  provided at the center and a tube-like member  101  that accommodates the member  100  in its inside. In this case, the bottom surface of the member  100  is an expansion effect surface  131   b , and the inner sidewall of the member  101  is the sidewall  132   b . The expansion effect surfaces  131   b  is movable in up and down along the sidewall  132   b . For example, the expansion effect surface  131   b  is placed at deeper position than the bottom surface of the peripheral recess  15 B as shown in  FIG. 14  before swage. At the moment of swage, the expansion effect surface  131   b  moves along the sidewall  132   b  to be closer to the bottom surface of the peripheral recess  15 B (See  FIG. 18 ) in order to contact with and deform the shaft  32 . 
     As shown in  FIG. 14 , the peripheral recess  15 B and the peripheral protrusion  14 B are arranged alternately in the circumferential direction of the rim  12 B. The peripheral protrusion  14 B is arranged to project in the longitudinal direction of the upper die  10 B (arrow direction) than the peripheral recess  15 B. The peripheral recess  15 B serves as a portion that allows the outward radial expansion of the shaft  32  when the shaft  32  is swaged. The peripheral protrusion  14 B serves as a portion that restricts the outward radial expansion of the shaft  32  during swage. 
     As shown in  FIG. 15 , the peripheral recesses  15 B are a strap-like bottom surfaces along the rim  12 B. This bottom surface may be a slope being inclined upwardly towards the center of the effect bottom  11 B, or may be a flat being parallel to the bottom surface of the peripheral protrusions  14 B. The peripheral recesses  15 B are formed at 6 locations by 60 degree interval in the circumferential direction of the upper die  10 B of a tubular or column-like shape. The number of the peripheral recesses  15 B should not be limited to 6 locations and, for example, it may be formed at 8 locations by 45 degree interval. Alternatively, it may be formed at 5 locations by approximately 72 degree interval. 
     Attachment Process 
     Next, the attachment process for attaching the female snap button  20 A to the sheet  1  using the upper die for button attachment  10 B of  FIG. 14  will be described.  FIG. 16  shows an arrangement view of the main components in up and down direction (axial direction) just before the female snap button  20 A being attached to the cloth that is one example of the sheet  1  and, from above, the upper die for button attachment  10 B, the female snap button  20 A, the sheet  1 , the fixing member  30 , and the lower die  40  for supporting the fixing member  30  are disclosed. The lower die  40  has, on its front surface, a support recess  41  that is capable to receive the base  31  of the fixing member  30 ; and when the fixing member  30  is placed in the support recess  41 , an axis of the shaft  32  of the fixing member is aligned with the axis of the upper die  10 B. 
     At an initial stage of attachment, the shaft  32  of the fixing member  30 , after pierced the sheet  1 , protrudes to the side of the coupling recess  21 A of the female snap button  20 A above after passing through the hole  24 A of the female snap button  20 A. Next, as shown in  FIG. 17 , the upper die  10 A is moved down (there may be a case where the lower die  40  is moved up) to accommodate the shaft  32  of the fixing member  30  by the expansion allowance portion  13 B of the effect bottom  11 B. From here, the upper die  10 A is further moved down (alternatively the expansion effect surface  131   b  is moved down along the sidewall  132   b ) resulting in that the distal portion  32   b  of the shaft  32  is press-deformed by the expansion effect surface  131   b  as shown in  FIG. 18 . Accordingly, the shaft  32  is expanded radially outwardly above the hole  24 A over the bottom surface  23 A′ of the bottom portion  23 A of the female snap button  20 A. A portion of this outwardly expanded allowance portion is press-deformed while it is received by the peripheral recess  15 B, and therefore rib  322   b  is formed inside of the peripheral recess  15 B and the female snap button  20 A is fixed onto the sheet  1 . By the attachment method using the upper die for button attachment according to the second embodiment, even in a case where the sheet  1  is thick, the shaft  32  of the fixing member  30  is gathered at the expansion allowing portion  13 B and is deformed relatively greatly towards the outer side in deformation direction to allow its remaining portion to expand towards the peripheral recess  15 B, and thus the required button attachment power is secured. Even in a case where the sheet  1  is thin, the outward and radial deformation of the shaft  32  is decentralized in the circumferential direction, less power is required for swage, and thus the load of the pressing machine is prevented to be greater. 
     Other Embodiments 
     Embodiments of the subject invention have been explained as above, however the descriptions and drawings partially consisting this disclosure should not be interpreted to limit the subject invention. For example, a brim  151  defining the border between the peripheral recess  15 A and the expansion allowing portion  13 A is provided between the peripheral recess  15 A and the expansion allowing portion  13 A of the upper die  10 A shown in  FIG. 5 , but this should not be a ground for limitation. For example, the strap-like bottom surface shown in  FIG. 5  may be formed to be a slope shape gradually inclined upwardly towards the expansion allowing portion  13 A, and the end of the strap-like bottom portion may be formed integrally and continuously with the circular recess  133   a  without the formation of the rim  151 . 
     The circular rib  323   a  shown in  FIG. 1  may be omitted. That is, as shown in  FIG. 19 , the button may be configured by a plate-like base portion  321   a  that is formed by a rise of the central portion, is positioned on the button body  20  (not shown in figure), and covers the hole  24  (not shown in Figure) and a portion of the bottom  23 A, and ribs  322   a  being formed integrally with the base portion  321   a  and onto a surface of the base portion  321   a  and extending radially from the center to the circumference of the base portion  321   a . The outer end of the rib  322   a  is not necessarily positioned on the outer edge of the base portion  321   a , and the external end of the rib  322   a  may be positioned at an inner side than the outer edge of the base portion  321   a.    
     The central recess  131   a , circular protrusion  132   a , and circular recess  133   a  may be omitted. That is, as shown in  FIG. 20 , the expansion allowing portion  13 C may be formed from the expansion effect surface  131   c  that is a press-surface for pressing the tip  32   d  of the shaft  32  at the time of swage, and the expansion peripheral surface  132   c  that is positioned around the expansion effect surface  131   c . In this case, the expansion effect surface  131   c  may be curved-surface or flat-surface. The expansion peripheral surface  132   c  may be curved surface or sloped surface expanding upwardly from the expansion effect surface  131   c  towards a rim  12 C. 
     In the example shown in  FIG. 11 , the rib  322   b  of the distal portion  32   b  of the shaft  32  is formed to be thinner than the base portion  321   b  in its thickness (sheet thickness direction). However, it should be appreciated that, as shown in  FIG. 21 , the thickness of the rib  322   c  and the base  321   c  at the distal portion  32   c  of the shaft  32  may be the same. Additionally, the member  100  and the member  101  shown in  FIG. 16  may be formed integrally. Further, as shown in  FIG. 17 , the expansion effect surface  131   b  is illustrated to be perpendicular to the sidewall  132   b  in figure, however, it may have a sectional reversed U-shape curved surface according to the shape of the button to be produced. 
     As explained above, it should be appreciated that various embodiments which are not clearly disclosed herein would be suggested by the subject invention, and they are modified and performed without departing from the spirits thereof at the time of reduction to practice. 
     REFERENCE SIGNS LIST 
     
         
           1  . . . Sheet 
           1   a  . . . First main surface 
           1   b  . . . Second main surface 
           10 A,  10 B . . . Upper die for button attachment 
           11 A,  11 B . . . Effect bottom 
           12 A,  12 B . . . Rim 
           13 A,  13 B . . . Expansion allowing portion 
           14 A,  14 B . . . Peripheral protrusion 
           15 A,  15 B . . . Peripheral recess 
           20  . . . Button body 
           20 A . . . Female snap button 
           20 B . . . Male snap button 
           21 A . . . Coupling-recess 
           21 B . . . Coupling-projection 
           22 A, 22 B . . . Side 
           23 A, 23 B . . . Bottom 
           24 A, 24 B . . . Hole 
           30  . . . Fixing member 
           31  . . . Base portion 
           32  . . . Shaft 
           321   a , 321   b  . . . Base portion 
           322   a , 322   b  . . . Rib 
           323   a  . . . Circular rib 
           40  . . . Lower die 
           41  . . . Support recess