| 摘要 |
PROBLEM TO BE SOLVED: To use a power-driven turning tool other than a hand control driver and ensure strength of a butterfly type head by providing a recessed part for fitting of the turning tool at the center of the top of a bolt with the butterfly type head capable of screwing by turning with fingers. SOLUTION: A wing bolt 1 is provided with a butterfly type head part 3, which is provided with a pair of right and left butterfly wings 4 extending in the orthogonal direction to the axial direction of the screw part 2 on a side surface of the butterfly head part 3, at one end of a screw part 2. A recessed part for fitting a turning tool which is composed of a cross recess 5 is provided at the center of a top 3a of the head part 3, and the crosswise direction of the cross recess 5 between lengthwise and crosswise directions is made agree with a projecting direction of the butterfly wings 4. Wall thickness near a base part of the butterfly wings 4 is thereby prevented from being thin, and strength against rotary torque can be ensured. A flange part 6 is formed with an outer periphery of a connection part of the head part 3 to the screw part 2 so as to provide a contact surface to an object to be secured, and the cross recess 5 is integrally formed with the butterfly wings 4 at the tune of closed die forging of the wing bolt 1. The manufacturing cost of the wing bolt 1 is thereby almost similar to those of conventional bolts, and the wing bolt can be rotated by power and a hand control driver, or directly rotated with hand.
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