FASTENER SYSTEM FOR FIXING HARDENED PLATES

摘要

A fastener element (150) comprises a frusto-conical portion (162) and a threaded portion (164). The smallest outer diameter of the frusto-conical portion is adjacent the threaded portion. The largest outer width of the threaded portion is smaller than the smallest outer diameter of the frusto-conical portion. The frusto-conical portion is hardened to a Brinell hardness of at least 300 HB. A fastener system (150) has an elongate shaft 172) and a head portion (162) having a generally annular shape, a hole (164), and means for engaging the inside of the hole with the shaft. The head portion engages with the shaft and is relatively harder than the shaft. A hardened plate (152) comprising a frusto-conical hole (160) therein for receiving a complementary fastener element (162) for fastening the hardened plate to a work piece. The plate has a Brinell hardness of at least 300 HB.