| 摘要 |
A blind fastener for securing workpieces is provided having as principle components a stem member, a drive-nut, and a deformable annular means. The stem member has an externally-threaded-portion on the accessible-side thereof, and may have a stem-head on the nonaccesssible side thereof. The drive-nut to be screwed onto the externally-threaded-portion of the stem member. The deformable annular means has as principle parts a head which is larger in diameter than the diameter of the boreholes of the workpieces, and an intermediate-part adjacent the head and having an outside diameter slightly smaller than the diameter of the boreholes, and a deformable tail-part adjacent the intermediate-part and abutting the stem-head for securing the workpieces when the fastener is set. The outer-portion of the stem member contains a turning means for rotating the stem member relative to the drive-nut. The stem member contains a break groove which is operative when the fastener is set and upon further rotation of the stem member relative to the drive-nut will cause the stem member to break at the break groove. The break groove is located at a point on the stem member which, when the fastener is set, is substantially flush with the top outer surface of the head. The fasteners of this invention are particularly useful for the aircraft industry and in particular in applications where the head is a countersunk type.
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