Patent ID: 7699568

Claim:
A fastening assembly having a screw attachment adapted to be disposed around a fastening piece secured to a main fastening body and sandwiched between a head of the fastening piece and a securing object so that the screw attachment bears a securing force of the fastening piece to press the securing object, the screw attachment comprising: a pair of radially expandable arms made of a shape restoring material and forming a ring having an inner diameter and an outer diameter, below a reverse transformation temperature of the shape restoring material, said pair of radially expandable arms having a securing force bearing shape with the inner diameter of the ring being smaller than an outer diameter of the head of the fastening piece and, at and above the reverse transformation temperature of the shape restoring material said pair of radially expandable arms having a restored shape with the inner diameter of the ring being larger than the outer diameter of the head of the fastening piece wherein said fastening piece has an inclined seating surface; the fastening assembly comprising: a main fastening body, a fastening piece screwed in the main fastening body, and a securing object having a through hole to pass the fastening piece, wherein the main fastening body has an internal thread engaged with the fastening piece, and a seat ring is disposed between the securing object and the screw attachment.