Screw attachment, fastening assembly having screw attachment, and process of releasing fastening assembly

Abstract

A screw attachment ( 10, 10′, 10″ ) disposed around a fastening piece ( 17 ) secured to a main fastening body ( 25 a ), the screw attachment sandwiched between a head ( 17 b ) of the fastening piece and a securing object ( 22 ) so that the screw attachment bears a securing force of the fastening piece to press the securing object. The screw attachment includes a pair of arms ( 12, 13 ) made of a shape restoring material. Each arm has a fore end, and the fore ends are joined to each other with an adhesive material that is softened when heated. The arms expands radially such that the screw attachment is released from the head of the fastening piece when heat or force is applied to the arms.

1 . A method disassembling a fastening assembly, the fastening assembly having a main fastening body, a fastening piece engaged with an internal thread of the main fastening body, a securing object having a through hole to pass the fastening piece, and a screw attachment disposed around the fastening piece and sandwiched between a head of the fastening piece and the 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, the 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, the method comprising the steps of:
 a) heating at least the screw attachment at or above the reverse transformation temperature of the shape restoring material;   b) causing the pair of radially expandable arms to horizontally radially expand such that the inner diameter of the ring is larger than the outer diameter of the head of the fastening piece; and   c) removing the screw attachment together with the securing object from the main fastening body.   
   
   
       2 . A method of disassembling a fastening assembly, the fastening assembly having a main fastening body, a fastening piece having an inclined seating surface and engaged with an internal thread of the main fastening body, a securing object having a through hole to pass the fastening piece, and a screw attachment disposed around the fastening piece and sandwiched between a head of the fastening piece and the 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, the 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, the method comprising the steps of:
 a) heating at least the screw attachment at or above the reverse transformation temperature of the shape restoring material;   b) causing the pair of radially expandable arms to horizontally radially expand such that the inner diameter of the ring is larger than the outer diameter of the head of the fastening piece; and   c) removing the screw attachment along the inclined seating surface together with the securing object from the main fastening body.   
   
   
       3 . A method disassembling a fastening assembly, the fastening assembly having a main fastening body, a fastening piece engaged with an internal thread of the main fastening body, and having a neck that is formed with an engagement shoulder larger than the internal thread in diameter, a securing object having a through hole to pass the fastening piece, and a screw attachment disposed around the fastening piece and sandwiched between a head of the fastening piece and the 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, the 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, the method comprising the steps of:
 a) heating at least the screw attachment at or above the reverse transformation temperature of the shape restoring material;   b) causing the pair of radially expandable arms to horizontally radially expand such that the inner diameter of the ring is larger than the outer diameter of the head of the fastening piece; and   c) removing the screw attachment together with the securing object from the main fastening body.   
   
   
       4 . A method disassembling a fastening assembly, the fastening assembly having a main fastening body, a fastening piece engaged with an internal thread of the main fastening body, a securing object having a through hole to pass the fastening piece, a compressed spring disposed between the securing object and the main fastening body to resiliently pressing the securing object against the main fastening body, and a screw attachment disposed around the fastening piece and sandwiched between a head of the fastening piece and the 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, the 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, the method comprising the steps of
 a) heating at least the screw attachment at or above the reverse transformation temperature of the shape restoring material;   b) causing the pair of radially expandable arms to horizontally radially expand such that the inner diameter of the ring is larger than the outer diameter of the head of the fastening piece;   c) removing the screw attachment together with the securing object from the main fastening body; and   d) automatically separating the securing object from the main fastening body with the compressed spring.