Patent ID: 8714883
Filing Date: 2014-05-06
Classification: E21D

Abstract:
1. A friction bolt, for frictionally engaging the internal surface of a bore drilled into a rock face, the friction bolt comprising: an elongate, generally circular tube which is expandable radially, the tube having a leading end and a trailing end, an expander mechanism disposed within the tube for applying a load tending to expand at least a section of the tube radially, an elongate tendon disposed longitudinally within the tube and in connection at or towards one end of the tendon with the expander mechanism and in connection at or towards an opposite end of the tendon with an anchor arrangement, the tendon being actuatable to expand the expander mechanism and to remain connected between the expander mechanism and the anchor arrangement while the expander mechanism is expanded, and an end fitting at the trailing end of the tube, the end fitting including a central opening through which the tendon extends, the opening being sized to frictionally engage the outer surface of the tendon to resist axial movement of the tendon within the tube and to position the anchor end of the tendon concentric with the tube, wherein the expander mechanism comprises a pair of expander elements, a first of which is secured relative to the tube and a second of which is secured to the elongate tendon, actuation of the tendon being operable to cause relative movement between the first and second expander elements to cause the expander mechanism to expand.