| 摘要 |
Torque indicating means are provided on a nut which is to be threaded on a shank wherein the nut is to rotate in unison with the shank until a predetermined torque is reached, at which stage a closure or stop 2 welded to the nut 1 at one end thereof fractures either along preformed zones of weakness 4 or at one or more welds 7, thereby enabling the bore through the nut to be opened by the shank so that the nut can rotate freely relative to the shank. The invention finds particular application as a means for indicating the extent of setting of a resin or like setting mixture during the installation of a resin or like bonded rock bolt. A dimple 8 is provided to provide an axial abutment for the bolt 10 to avoid sharp edges coming into contact with the closure 2 and severing it prematurely. <IMAGE> |
