Improvements in self-drilling rock bolts

摘要

An improved method for installing a self-drilling rock bolt (10) as well as components and tools for use in the installation of such bolts is disclosed. The rock bolt (10) has a central bore (14), a drill bit (18) mounted at one distal end, and a nut (16) mounted on the other end. An assembly comprising a plate (102) having an aperture defining an engagement surface, and a part convex dome ball (120) defining a central bore having a central axis for receiving the rock bolt (10) and a convex external surface slideably engaged with the engagement surface of the plate is against a rock face; The rock bolt is then rotated to drill a hole in the rock face using the drill bit until the rock bolt is almost fully located inside the hole. The nut (16) defines springy arms (44) which engage with the dome ball (120) preventing axial movement of the nut and therefore the entire bolt, relative to the plate, while permitting relative rotation of the nut and plate. Next, an elongate generally cylindrical capsule (50) containing a two part resin separated by a film and having a first end and a second end is inserted into the bore of the rock bolt the first end of the capsule being covered by a cap. A plunger device (200) is used to apply a force to the cap, forcing the cap and capsule into the bore thereby forcing resin through the mixing means and out past the drill bit into the hole. The resin is allowed to set and the nut is turned using the plunger device (200) to tension the rock bolt.