Patent ID: 9394934
Filing Date: 2016-07-19
CPC Classification: B21D,B21J,B21K,B23P,F16B,F16F,Y10T

Claim Text:
1. A fastening method for fastening a nut to a bolt by screwing, the fastening method comprising: preparing a nut including a tool mounting portion formed on a side of a seat surface, and an annular thin portion formed on the tool mounting portion opposite to the seat surface, supporting the bolt at a position of the bolt opposite to where the nut is attached using a work support base which is configured to be movable along an axial direction of the bolt, and swaging a plurality of places of the thin portion with punches from an outer circumferential direction in a state where the nut is fastened to the bolt, wherein the swaging causes a thickness of the thin portion to plastically deform so as to extend to a front end of the bolt partially in a circumferential direction to be closely adhered to a screw portion of the bolt, and wherein the work support base and the bolt move in a direction opposite to the front end of the bolt in accordance with a progress of the swaging.