Abstract:
There is provided a tapping screw having a high anti-loosening effect and a high pull-out resistance for resin-molded components. A tapping screw 1 according to the present invention is configured such that an intersection P between a root 10 and a clearance flank 8 of a thread 7 is set such that a first engaging rate ρ1 exceeds 50%, the first engaging rate ρ1 being percentage of an actual engaging height H1 to a hole 6 against a first thread height H2 from a crest of the, thread 7 to the intersection P, an intersection Q between the root 10 and a pressure flank 9 of the thread 7 is set such that a second engaging rate ρ2 is smaller than the first engaging rate ρ1 and no smaller than 50%, the second engaging rate ρ2 being percentage of the actual engaging height H1 to the hole 6 against a second thread height H3 from the crest of the thread 7 to the intersection Q, and the root of the thread inclines downward toward a tip direction, extending from the intersection P to the intersection Q thus set. By setting the first engaging rate ρ1 and the second engaging rate ρ2 in this manner, the root 10 inclining downward toward the tip direction provides a high pull-out resistance and a high anti-loosening effect.
Abstract:
A locking screw including a male screw and a female screw, the male screw being screwed into the female screw, the male screw including male threads and the female screw comprising female threads, wherein a male thread comprises a crest side flank surface and a root side flank surface connecting the crest side flank surface and a root of the male thread, a slope of the crest side flank surface is smaller than a slope of a female flank surface of the female thread, a slope of the root side flank surface is larger than the slope of the female flank surface, a connected portion of the crest side flank surface and the root side flank surface interferes with the female thread, and a clearance is formed between the root side flank surface and the female screw when the connected portion interferes with the female thread.
Abstract:
A locking screw includes a head and a leg that has a thread formed thereat. The screw is screwed into a female screw hole, at which a female screw is formed. An angle formed by flank surfaces on a root side of a male screw is smaller than an angle formed by flank surfaces constituting the female screw whereas a vertex formed by the flank surfaces on the crest side of the male screw is an obtuse angle greater than 90°. Furthermore, the flank surface on the root side and the flank surface on the crest side are connected to each other via an arcuate surface. The width of the crest of the male screw is greater than the width of the root of the female screw mating with the crest of the male screw. The resultant locking screw can exhibit a locking function on the thread crest side of the male screw. The male screw can be efficiently brought into contact with the female screw-so as to-interfere therewith, thus securely inhibiting the male screw from being loosened.
Abstract:
The present invention provides a screw, comprising a screw head having a drive recess and a screw shank having threads and being integrally formed with the screw head, wherein the drive recess includes a plurality of engaging grooves equiangularly radiating from an axis of the screw in plan view, a bottom face of each engaging groove having a steep slope, which is near to the screw shank, and a gentle slope, which is far from the screw shank, for enlarging the engaging area of the engaging grooves.
Abstract:
The present invention provides a screw, comprising a screw head having a drive recess and a screw shank having threads and being integrally formed with the screw head, wherein the drive recess includes a plurality of engaging grooves equiangularly radiating from an axis of the screw in plan view, a bottom face of each engaging groove having a steep slope, which is near to the screw shank, and a gentle slope, which is far from the screw shank, for enlarging the engaging area of the engaging grooves.