| 摘要 |
<p>A fastener including a metal portion having a threaded shank adapted to be threaded into a workpiece, a head and an annular flange between the head and the shank. The surface of the head and the upper surface of the flange are irregular so that, when a plastic head is molded around the head and flange of the metal portion, the metal and plastic portions are relatively fixed to each other. The plastic portion includes a section which extends around the periphery of the flange and under the marginal portion of the latter and which mates with an annular deformation extending around the periphery of the underside of the flange to reduce the possibility of failure of the plastic portion as that portion is forced against a workpiece. The section of the plastic portion under the flange is annular and may provide a recess for receiving a resilient sealing ring or, in the alternative, it may be formed with an annular rib which deforms and forms a seal as the fastener is threaded down to bring the annular section into engagement with the workpiece.</p> |
