| 摘要 |
In rock or roof bolts, in particular combined rigid profile and stretch or strain roof bolts, the bolt bar, except for the bar tip is surrounding by a sheathing tube and the end thereof projecting out of the drillhole mouth is made tensionable with respect to the rock by means of an anchor plate and a screw means. To ensure the immediate loadbearing capability of such a roof or rock bolt, in particular in the filling mortar method, at least one portion (5) of the sheathing tube (3) is provided as expansion element with cutouts (7) distributed into slots (8) and the bolt tip (2) is formed as abutment.
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