| 摘要 |
<p>Rolled bars suited for use as reinforcement, particularly in mining applications. The bar of the invention allows employment of a bar with a smaller average diameter than a conventional bar of the same stength and material composition. In a preferred form, the bar comprises a length of substantially circular cross section bar having a rolled deformation (2B) located symmetrically thereon throughout its entire length; the deformation comprising raised surfaces above a minor diameter (3B) of the bar; at least one end portion of the length having a threaded portion (4B) included in the raised surfaces; the threaded portions not extending in depth to the minor diameter. In one embodiment shown the rolled deformation is in the form of a spiral suitable for receiving a coarsely threaded nut. The bar is particularly suited to application as a rock bolt, allowing for the initial use of a finely threaded nut threaded thereon, followed after a blasting operation by the use of a coarsely threaded nut.</p> |
