| 摘要 |
The invention relates to a countersunk screw (1) having a threaded shank (2) and a countersunk head (4), which latter has a conical surface (6) tapering at a countersinking angle (.alpha.) in the direction of the threaded shank (2). The conical surface (6) has a plurality of ribbed protrusions (16) distributed over the periphery and jointly defining a conical enveloping surface with a cone angle (.beta.). ~The countersinking angle (.alpha.) of the conical surface (6) is less than the cone angle (.beta.) of the ribbed protrusions (16). The ribbed protrusions (16) have outer bearing surfaces (18), which define the conical enveloping surface and which, in terms of their areal size, are dimensioned in dependence on a material-specific surface pressure such that, in a screw application for fastening fittings or the like by screwing into a sinkhole between the ribbed protrusions (16) and the respective sinkhole, a certain, surface-damage-preventing surface pressure is generated. The ribbed protrusions (16) are additionally designed such that, in a screw application involving direct, countersinking screwing into a soft material, such as, in particular, wood, they have a milling effect.
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