Patent ID: 9341210
Filing Date: 2016-05-17
CPC Classification: F16B

Claim Text:
1. A fastener, comprising: a first member including a flange portion, and a leg portion extending from the flange portion, forming an insertion hole opening at the flange portion, divided around a shaft line to form a plurality of leg pieces, and formed with a guided portion in an inner circumferential portion of the insertion hole opening; and a second member having a base portion on one end thereof and a guide portion formed from a vicinity of another end of the second member toward the base portion, and pressed into the insertion hole opening of the first member so as to contact the guide portion with the guided portion and to expand the plurality of leg pieces, wherein the guide portion has a curved surface curved outwardly and having a tangent angle changing relative to the shaft line at a contact point with the guided portion from another end side toward a base portion side, and an insertion force into the first member at the contact point is held approximately constant, and the guide portion of the second member is arranged so that when Young's modulus of the leg portion is presumed to be constant, and a frictional force at the contact point is presumed to be 0, and an opening amount of each of the plurality of leg pieces at an arbitrary point on the curved surface is V and the tangent angle is θ, a relationship of V sin θ=constant is established at the arbitrary point on the curved surface.