Patent ID: 8974151
Filing Date: 2015-03-10
Classification: E02D,E21D

Abstract:
1. A constant-resistance large-deformation anchor rod, comprising a rod body, a tray, a nut, and a constant-resistance device, wherein the rod body has an outer surface, wherein the outer surface of the rod body has a helically thread structure; wherein the nut has an inner surface, wherein the inner surface of the nut has a helically thread structure; and wherein the constant-resistance device comprises a cylindrical structure having an inner surface and an outer surface, wherein the inner surface of the cylindrical structure has a helically thread structure and the outer surface of the cylindrical structure has a helically thread structure, wherein the helically thread structure of the outer surface of the cylindrical structure of the constant-resistance device matches the helically thread structure of the inner surface of the nut, and the helically thread structure of the inner surface of the cylindrical structure of the constant-resistance device matches the helically thread structure of the outer surface of the rod body for providing a stable work resistance, wherein in use, the constant-resistance device is threadedly sleeved onto a tail portion of the rod body, and the tray and the nut are sleeved onto a tail end portion of the constant-resistance device in turn, and wherein the nut is in a threaded connection with the constant-resistance device; when an axial tensile force acting on the anchor rod exceeds a static friction force between the constant-resistance device and the rod body, a relative displacement occurs between the rod body and the constant-resistance device, and the anchor rod is elongated; meanwhile, a micro deformation in a radial expansion form takes place in the constant resistance device for the relative displacement; during the relative displacement, the stable working resistance remains between the constant-resistance device and the rod body; and when the axial tensile force decreases to be equal to the static friction force between the constant-resistance device and the rod body, the constant-resistance device and the rod body return to the relatively static state without any further relative displacement, with the constant-resistance device restoring from the micro deformation state to the original state and thereby tightly sleeved onto the rod body again.