| 摘要 |
A fastener for use in concrete includes a shank and a head. The shank has a tip distal most from the head. The shank includes a first helical thread formation having a thread form thereon formed from two portions disposed upon opposite lateral sides of the thread form. The thread form has a root and the two portions include an alternating series of lobe members and base portions. The lobe members have a height as measured from the root and the base portions have a height as measured from the root. The height of the lobe members is greater than the height of the base portions and the height of the base portions is greater than zero. The fastener includes a second helical thread formation that is disposed adjacent to and spaced from the first helical thread formation. |
