Radially expanding plug for fixing screw in masonry bore - has axial V=grooves in bore and barrel, with former having radial and tangential walls

摘要

The plug comprises a sleeve with five or six grooves in both the bore and the barrel. the plug is of relatively rigid and inelastic synthetic material, the grooves running parallel to the axis of revolution, and the core void taking the form of a ratchet wheel in cross section. Each groove is thus, of a ratchet tooth section with a radial (3) and a tangential (4) wall, its edges locating on an inner circle (1). An angle of 30 deg. is subtended by the walls (3, 4) of each groove, a trapezoidal section tooth (8) being built onto the back of each tangential wall (4), and the walls otherwise being of uniform thickness. The geometry is such that max wall thickness centres (9) on the tangential walls (4), with a min applying between bore grooves.