Blind fastener assembly

A blind fastener assembly, adapted to be installed in a workpiece having a first and a second surface with an opening extended therebetween, said blind fastener assembly comprising:

• expander means including an enlarged head at one end thereof formed to bear against the first surface of the workpiece, a tapered nose portion at the other end thereof, a shank portion therebetween, and a bore therethrough, said shank portion being dimensioned to fit into and extend through the opening in the workpiece wherein said tapered nose portion and a portion of said shank portion extend beyond the second surface of the workpiece;
• a pin member including an enlarged head and an elongated shank portion extending from said enlarged head, said elongated shank portion being received within said bore in said expander means, one end of said elongated shank portion being disposed adjacent to said tapered nose portion of said expander means and the other end of said elongated shank portion being disposed adjacent to said enlarged head of said expander means;
• resilient washer means comprising a coil spring having a predetermined radial thickness and an outer diameter, said coil spring being positioned about said pin member shank portion between said tapered nose portion and said one end of said elongated shank portion of said pin member, said coil spring being dimensioned to fit through the opening in the workpiece in its unexpanded state and being formed to be axially moved toward the second surface of the workpiece and unwound and expanded over said tapered nose portion to its fully expanded condition disposed entirely on said shank portion of said expander means;
• and
• expandable sleeve means having a first end and a second end, said expandable sleeve means being carried on said pin member shank portion with said first end disposed adjacent said coil spring and said second end disposed adjacent said one end of said elongated shank portion of said pin member and dimensioned to pass through the opening in the workpiece, said sleeve means having a counterbore at said first end thereof, said counterbore forming an annular wall at said first end having an inner diameter less than the outer diameter of the coil spring and extending over a portion of the axial length of said expandable sleeve means wherein the radial thickness of said annular wall is less than said radial thickness of said coil spring, said second end of said sleeve means being operably engaged with said pin member, said first end of said sleeve means abutting said coil spring and advancing towards the second surface of the workpiece when said pin member is axially displaced relative to said expander means, said sleeve means being proportioned to expand over said expander means tapered nose portion and force said coil spring to expand over said tapered nose portion and said shank portion of said expander means ahead of said first end of said sleeve to said fully expanded condition of said coil spring when said pin member is fully axially displaced such that the entire annular surface bearing area of said coil spring bears against the second surface of the workpiece.