Patent ID: 6969220

Claim:
A wall anchor for a screw of the type having a longitudinal axis comprising: two shafts having a respective generally tubular form of revolution about the axis and mutually opposed longitudinally; said two shafts comprising a head shaft having an internally free coaxial passage for a screw rod of the screw and bearing externally a transverse longitudinally end collar; a screw nut shaft having on the inside a coaxial internal screw thread capable of co-operating with said screw rod and bearing at its outer periphery a plurality of approximately longitudinal teeth distributed angularly about the axis, and forming a longitudinal projection with respect to the screw nut shaft longitudinally opposite to the head shaft with respect to the screw nut shaft; a plurality of approximately longitudinal bars distributed angularly about the axis disposed between the head shaft and screw nut shaft, said bars being plastically flexible in a direction away from the axis , in order to pass from an initial configuration to an anchoring configuration of the wall anchor; and each tooth converges towards the axis in a longitudinal direction going from the head shaft towards the screw nut shaft, and which tooth has a generally triangular shape defined by a side for connection to the screw nut shaft and by two free sides, said free sides forming cutting edges and come together to form a point such, that the teeth together define a point symmetrical with respect to the axis, projecting longitudinally on the screw nut shaft in said longitudinal direction.