Expansion fastening system with quick lock and release

A fastening device comprising in combination an assembly of a first fastening member and a second fastening member, the first fastening member being adapted to secure a first object to a second object when the second fastening member is inserted into the first fastening member;

• the first fastening member comprising
• a first head having an aperture extending throughout the first head, an inside surface, and an outside surface,
• a guide on the side of the inside surface to direct the second fastening member in a straight direction within the first fastening member,
• a neck having two opposite ends and an opening extending from one end to the opposite end, the opening being substantially concentric with the aperture, one end being connected to the inside surface of the first head;
• and
• a pair of expanding bodies, at least one of the expanding bodies having an engaging edge, the expanding bodies being flexibly connected to the end of the neck opposite the end connected to the inside surface of the head, the expanding bodies extending in a direction generally perpendicular to a plane containing the inside surface of the head, the expanding bodies disposed in a generally transverse relation with respect to each other, such that the expanding bodies are forced to open upon insertion of the second fastening member into the first fastening member through the aperture from the first surface;
• the second fastening member comprising an elongated body having
• an exterior portion, a back end constituting a second head and a pointed front end opposite to the back end, a diameter commensurate to the aperture of the first head of the first member, and a center axis,
• the exterior portion having
• an optional leading recessed engaging surface having a continuity from a front point located towards the pointed front end to a back point located towards the second head, and
• a retracting recessed engaging surface also having a continuity from a front point located towards the pointed front end to a back point located towards the second head,
• the leading surface and the retracting surface having a common back point, with the option that the leading surface and the retracting surface may be one and the same engaging surface,
• each recessed surface also having
• a bottom throughout said recessed surface, the bottom being closer to the center axis at the back point than at any other point adjacent to the back point, excluding points behind the back point, and
• an active wall adaptable to coact with and be guided by the first engaging edge, the active wall having a tangent, the projection of the tangent on a plane containing the center axis and being parallel to the tangent forming an angle with the center axis smaller than 90 degrees;
• the first engaging edge of the first fastening member being adaptable to apply pressure to any point of the bottom of the recessed area that the first engaging edge is in contact with, and the distance of which from the center axis is equal or greater than that of the distance of the back point from said back axis;
• and
• the first engaging edge of the first fastening member and the back point being equidistant from the first head when the second fastening member is driven entirely through the aperture of the first fastening member.

A fastening device comprising in combination an assembly of a first fastening member and a second fastening member, the first fastening member being adapted to secure a first object to a second object when the second fastening member is inserted into the first member;

• the first fastening member comprising
• a first head having an aperture;
• and
• an expanding body having an engagement edge, the expanding body being connected to and extending away from the head;
• the second member comprising an elongated body having
• a second head at one end, the second head having a shape adaptable to be turned by a driving tool;
• a leading point at the opposite end;
• a diameter commensurate to the aperture of the first fastening member;
• and
• threadline along at least part of the elongated body, with the requirement that the engagement edge is in yielding cooperation with and applies pressure on the threadline at an engagement position when the second member is completely inserted in the first member, so that
• the second member may be inserted completely in the first member without the second member turning when an adequate direct insertion force is applied on the second member through the aperture, and
• when the second head is turned by the driving tool in a preselected direction, after the second member has been completely inserted in the first member, the second head is forced to be at least partially advanced away from the first head,
• the diameter of the threadline becoming smaller at the engagement position as compared to the diameter of the threadline in front of it toward the leading point.

A fastening device comprising in combination an assembly of a first fastening member and a second fastening member, the first fastening member being adapted to secure a first object to a second object when the second fastening member is inserted into the first member;

• the first fastening member comprising
• a first head having an aperture extending throughout the first head, an inside surface, and an outside surface,
• a guide on the side of the inside surface to direct the second fastening member in a straight direction within the first fastening member,
• a neck having two opposite ends and an opening extending from one end to the opposite end, the opening being substantially concentric with the aperture, one end being connected to the inside surface of the first head;
• and
• a pair of expanding bodies, at least one of the expanding bodies having an engaging edge, the expanding bodies being flexibly connected to the end of the neck opposite the end connected to the inside surface of the head, the expanding bodies extending in a direction generally perpendicular to a plane containing the inside surface of the head, the expanding bodies disposed in a generally transverse relation with respect to each other, such that the expanding bodies are forced to open upon insertion of the second fastening member into the first fastening member through the aperture from the first surface;
• the second member comprising an elongated body having
• a second head at one end, the second head having a shape adaptable to be turned by a driving tool;
• a leading point at the opposite end;
• a diameter commensurate to the aperture of the first fastening member;
• and
• threadline along at least part of the elongated body, with the requirement that the engagement edge is in yielding cooperation with and applies pressure on the threadline at an engagement position when the second member is completely inserted in the first member, so that
• the second member may be inserted completely in the first member without the second member turning when an adequate direct insertion force is applied on the second member through the aperture, and
• when the second head is turned by the driving tool in a preselected direction, after the second member has been completely inserted in the first member, the second head is forced to be at least partially advanced away from the first head,
• the diameter of the threadline becoming smaller at the engagement position as compared to the diameter of the threadline in front of it toward the leading point.