| 摘要 |
<p>A tamper resistant screw (30) comprises a shank ((31) and a head (30a) having a top surface (32) on the opposite side thereof to the shank (31) and there being at least five channels (18) in the top surface (32) extending radially from a central part (35) of the top surface (32) disposed transversely of the longitudinal axis (X-X) of the shank (31), the channels (18) each having side surfaces (20) at opposite sides of a bottom surface (21), the side surfaces (20) being disposed at equal distances from and on opposite sides of a radial plane (P) containing the longitudinal axis (X-X) of the shank (31) and being of increasing depth from a minimum depth where they are closest to the central part (35) to a maximum depth at the periphery of the head (30a) and no channel (18) being disposed diametrically opposite any other channel.</p> |
