Patent ID: 8070040

Claim:
A pre-tensioned breakaway fastener assembly for use in attaching a tooling member to an assembly device, the fastener assembly comprising: an upper annular plate having a first through bore; a lower annular plate axially spaced from the upper plate and having a first through bore axially aligned with the upper plate first bore, one of the first and the second annular plates having at least one second through bore radially spaced from the respective first through bore; a breakaway fastener having a head, an end opposite the head, an elongate shank between the head and the end, and an assembly device threaded engagement portion adjacent the end, the fastener shank further having a predetermined fracture portion having a narrowed cross section portion positioned on the shank between the head and the breakaway fastener assembly device threaded engagement portion, the breakaway fastener axially positioned through the upper and the lower plate first bores; a compressible spring member positioned between the upper and lower plates radially spaced from the shank; and at least one compressive fastener radially spaced from the breakaway fastener and axially positioned through the second bore in one of the upper or lower plate and removably engagable through contact with the other of the plates to axially compress the spring member, wherein the breakaway fastener is adapted to be pretensioned on disengagement of the compressive fastener with the other of the plates.