| 摘要 |
The invention concerns a fastener comprising a foot and a head comprising a plate to which said foot is linked, a wedge and a shank connecting said plate to said wedge, which comprises a back-plate, a rim and flexible arms connecting said rim to said back-plate, each arm comprises a first and a second curved section, and an elbow connecting them, said first section is connected to said back-plate by a first end of said arm and said second section is connected to said rim by a second end of said arm, said back-plate and each flexible arm are configured such that the distance between the center of said back-plate and said second section increases along said second section from said elbow to said rim. |
