Self drilling rock bolt

A self drilling rock bolt comprising first and second ends, a shaft extending between the ends, and an anchoring device, the first end having a drill tip to penetrate rock, the drill tip extending radially a distance greater than the radius of the shaft to provide a passage to convey fluids between the shaft and the wall of the drilled hole, the second end being adapted to be connected to a drilling apparatus to allow rotation of, and thrust to, the bolt, the anchoring device being operative to retain the bolt when located in a drilled hole and comprising a mandrel having one or more external surfaces that are inclined to the shaft, the mandrel being mounted to, or integrally formed with, the shaft and at least one expansion element overlaying the mandrel, wherein the at least one expansion element is displaced radially outwardly on a predetermined relative movement between the mandrel and the at least one expansion element.

A self drilling rock bolt comprising first and second ends, a shaft extending between the ends, and an anchoring device, the first end having a drill tip to penetrate rock and the second end being adapted to be connected to a drilling apparatus to allow rotation of, and thrust to, the bolt, the anchoring device being operative to retain the bolt when located in a drilled hole and comprising a mandrel having one or more external surfaces that are inclined to the shaft, the mandrel being mounted to, or integrally formed with, the shaft and at least one expansion element overlaying the mandrel, wherein the at least one expansion element is displaced radially outwardly on a predetermined relative movement between the mandrel and the at least one expansion element, the bolt being arranged to allow fluid to be passed between the ends when located in a drilled hole and the shaft incorporates an inner passage through which fluid is arranged to pass between the first and second ends.

A self drilling rock bolt comprising first and second ends, a shaft extending between the ends, an anchoring device, and a drill bit connected to an end of the shaft and incorporating a drill tip thereon which forms the first end of the bolt and is arranged to penetrate rock, the second end of the bolt being adapted to be connected to a drilling apparatus to allow rotation of, and thrust to, the bolt, the anchoring device being operative to retain the bolt when located in a drilled hole and comprising a mandrel having one or more external surfaces that are inclined to the shaft, the mandrel being mounted to, or integrally formed with, the shaft and at least one expansion element overlaying the mandrel, wherein the at least one expansion element is displaced radially outwardly on a predetermined relative movement between the mandrel and the at least one expansion element, and the drill bit being connected to the end of the shaft by a coupling that is arranged to impart rotation to the drill bit from the shaft when the shaft is rotated in at least one direction.

A self drilling rock bolt comprising first and second ends, a shaft extending between the ends, and an anchoring device, the first end having a drill tip to penetrate rock and the second end being adapted to be connected to a drilling apparatus to allow rotation of, and thrust to, the bolt, the anchoring device being operative to retain the bolt when located in a drilled hole and comprising a mandrel having one or more external surfaces that are inclined to the shaft, the mandrel being mounted to, or integrally formed with, the shaft, at least one expansion element overlaying the mandrel, and a connector, wherein the at least one expansion element depends from the connector and is displaced radially outwardly on a predetermined relative movement between the mandrel and the at least one expansion element, and the connector is captured to prevent axial movement of the at least one expansion element along the shaft.

A self drilling rock bolt comprising first and second ends, a shaft extending between the ends, a drive coupler connected to the shaft, and an anchoring device, the first end having a drill tip to penetrate rock and the drive coupler being disposed adjacent the second end and being adapted to be connected to a drilling apparatus to allow rotation of, and thrust to, the bolt, the anchoring device being operative to retain the bolt when located in a drilled hole and comprising a mandrel having one or more external surfaces that are inclined to the shaft, the mandrel being mounted to, or integrally formed with, the shaft and at least one expansion element overlaying the mandrel, wherein the at least one expansion element is displaced radially outwardly on a predetermined relative movement between the mandrel and the at least one expansion element.