| 摘要 |
A blind fastener for fastening workpieces of a crushable or composite material and which provides a blind head having a large bearing area against the adjacent blind side of the workpieces and having a main sleeve with a tapered nose and an expandable sleeve with the expandable sleeve having a primary section and a secondary section with the secondary section having a wall of reduced cross-sectional area and of a lower hardness and/or material strength than the primary section such that after the secondary section has moved past and been expanded over the tapered nose the leading end of the primary section will substantially not move radially inwardly as it is moved over the tapered nose and at a preselected axial or column load the secondary section will substantially fold or collapse to form the blind head with a large bearing area while the primary section will substantially not buckle whereby the pin can provide a visual and/or measurable indication that the fastener has been installed in a proper grip condition. |
