| 摘要 |
A blind fastener with an axially extending sleeve having an axially extending internally threaded passage therethrough. A head at one end has an axially facing surface thereon with a periphery which is centered on its axis. A mandrel includes an axially extending threaded shank that is threaded into and through the passage. A torque-off groove is formed on the shank. Torque tool engaging surfaces are accessible at the head end of the sleeve, and blind upsetting structure is axially movable by rotating the mandrel to form an enlarged body at the unheaded end of the sleeve. A nut is threaded to the mandrel with a bearing face facing toward the surface of the head of the sleeve. The bearing face of the nut is concavely shaped so as to make contact with and thereby to make a retention engagement with at least some points around the periphery to hold the sleeve against rotation relative to the nut when the mandrel is drawn into the sleeve with the nut pressed against the head.
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