| 摘要 |
<p>The invention relates to a rock bolt (1) comprising a sleeve-like outer bolt portion (2) and an inner bolt portion (3) within the outer bolt portion, which bolt portions can be pushed within each other. The outer bolt portion is provided at its front and rear end with internal threads (5, 11) opposite in screw direction. The inner bolt portion (3) is provided at the front end with adjacent threads (5, 12) opposite in screw direction with respect to each other but equal in screw direction with respect to the thread (4, 11) of the outer bolt portion on that side. The bolt can be installed in a hole by pushing it first into the hole with the portions (2, 3) within each other, whereafter the inner bolt portion is screwed off the outer bolt portion, withdrawn from within the outer bolt portion and attached to the rear end of the outer bolt portion by means of the threads (12, 11).</p> |
