| 摘要 |
PURPOSE:To increase the strength of a bolt by a method wherein the circumference of core material having the threaded shape nearly equal to that of the bolt to be wrought is covered with a synthetic resin layer containing reinforced fiber and then the layer is hardened with a bolt molding die. CONSTITUTION:The circumference of the core material 1 is covered with a synthetic resin layer 2, 2 containing reinforced fiber and compression is applied to the bolt molding dies in the direction of the arrow. In this manner, undulation is imparted to the resin layer 2, 2 along the shape of a thread, stuck closely to the surface of the core material and the resin in the resin layer 2, 2 is hardened keeping such a state. Accordingly, the hardened resin layer 2',2' containing reinforced fiber is stuck solidly to the surface of the core material 1 to provide a synthetic resin bolt. |
