Patent ID: 7322222

Claim:
A press molding device for press molding of a sheet blank, the sheet blank comprising a product section and a grip section surrounding the product section, the device comprising: an upper die being provided with alternately disposed protruding corners and indented corners; and a lower die being provided with alternately disposed protruding corners and indented corners so as to mesh with the upper die; wherein the device is configured to press mold a bead comprising grooves and tongues disposed alternately within the grip section by meshing the upper die and the lower die, wherein the device is configured to press mold the product section while gripping the bead with the upper die and the lower die; wherein the upper die and the lower die are provided with a first protruding corner, a second protruding corner, a third protruding corner, and a fourth protruding corner disposed within the grip section from an outer periphery of the grip section towards an inner periphery thereof; wherein the upper die comprises the first protruding corner and the third protruding corner, wherein the first protruding corner and the third protruding corner are configured to form grooves; wherein the lower die comprises the second protruding corner and the fourth protruding corner, wherein the second protruding corner and the fourth protruding corner are configured to form tongues; wherein a subtended angle of the first protruding corner and a subtended angle of the fourth protruding corner are greater than or equal to 90 degrees and less than or equal to 120 degrees.