Button and Upper Die for Button Attachment

A button comprising:

• 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, wherein
• a distal portion of the shaft comprises:
• 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.

An upper die for button attachment for swaging a distal portion of a shaft that projects towards a first main surface side and passes through a hole of a button body towards the first main surface side, wherein the button body with the 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 wherein 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 comprising:

• an effect bottom that contacts with the shaft for swaging the shaft, wherein
• the effect bottom comprises:
• 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.