| 摘要 |
A screw-threaded fastener 10 for attaching articles 28 of predetermined thicknesses to sheet metal 30, the fastener 10 including a head 12 at one end, a generally cylindrical elongate shank, a tip 22 at the other end, a plurality of discrete threaded sections 26a and 26b on the shank and at least one annular unthreaded shank portions 24 between each pair of the thread sections 26a and 26b. The annular unthreaded shank portion 24 is spaced from the head at a predetermined distance or at predetermined distances which correspond to the predetermined thickness of articles to be fastened. Thus, when the head 12 of the fastener 10 is seated, the fastener is free to rotate without continued advancement with the sheet metal 30 being located at the unthreaded portion 24. Naturally when a plurality of unthreaded portions 24 are included the fastener 10 can accommodate articles of different thickness. The annular portions 24 can be given a greater axial extent to allow the screw to move relative to the panel when the panel is compressed in the vicinity, thereby preventing the screw head from penetrating an overlying membrane. <IMAGE> |
