| 摘要 |
PROBLEM TO BE SOLVED: To prevent a torque increase in a driver by forming a driving part whose diameter is enlarged from a tip end to a screw thread on an axial part tip end part, end forming an acute-angled blade in a screwing rotational direction on a circumferential surface of the driving part. SOLUTION: A screw thread 22 is formed around an axial part 21 of a wood screw 20, a driving part 23 whose diameter is enlarged is formed on a tip end part of the axial part 21 so as to bend from a tip end to an axial part 21, and a blade 24 having an acute angle in a rotational direction is formed around the driving part 23 in order to drive a screw in an object material. When a wood screw 20 is driven down into the object material by a driver, the wood screw 20 can be driven with a low resistance if the object material is made of sheet metal since the tip end part of the driving part 23 is formed in a sharply acute shape like an artillery shell shape. Also, if a conventional wall thickness part is generated on a penetrating hole formed on the sheet metal by a blade 24, the wall thickness part can be cut. Even if the wood screw 20 is completely screwed in the object material, the axial part 21 is fastened tightly on an edge part of the penetrating hole. It is thus possible to prevent increase of rotating resistance, and it is also possible to prevent a torque increase. |
