Patent ID: 8196498

Claim:
A method for applying a continuous punching to a chain roller; wherein, a raw block having a first surface and a second surface; said method comprising steps of: a first punching: said first surface of said raw block being punched to form a first chamfering indentation; a second punching: said first chamfering indentation of said first surface being further punched to form a second chamfering indentation larger than said first chamfering indentation; said second surface being punched to form a first square indentation; a third punching: said second chamfering indentation of said first surface being punched to form a second square indentation; a fourth punching: two third square indentation being formed by punching said first surface and said second surface, respectively, thereby propelling a middle wall between the two third square indentations outside said raw block via a first blanking, so that a first opening having two first chamfer surfaces respectively disposed at two ends thereof being formed; a fifth punching: said first chamfer surfaces disposed at said two ends of said first opening being compressed toward an interior of said first opening to form a stepped hole; and a sixth punching: a redundant thickness of said stepped hole being propelled outside said raw block via a second blanking to form a second opening with two second chamfer surfaces; a height of each said second chamfer surface being greater than 0% to 5% of a height of said second opening.