High strength blind bolt with uniform high clamp over an extended grip range

摘要

In general a blind fastener for securing workpieces is shown and which blind bolt has a core pin with a blind side head and a plurality of threads or locking grooves and a nut adapted to be threaded onto the pin threads; the blind bolt which has a main sleeve structure and an expandable blind side sleeve structure is set by a relative axial force applied to the pin which forces the expandable sleeve structure against the main sleeve structure causing the expandable sleeve to expand and form a load bearing blind head; the blind fastener includes a grip adjuster structure which defines a cavity having a depth selected to define the grip range of the fastener with the grip cavity generally located externally of the workpieces; the core pin head acts on the expandable sleeve and main sleeve structures to cause a frangible portion in the grip adjuster structure to shear and receive the main sleeve structure after which the blind head engages the blind side of the workpieces, with none of the clamp load developed being shared by the main sleeve structure. The blind threaded fastener can be adapted to be installed by the same installation tool used to install non-blind threaded fasteners of the same nominal diameter.