| 摘要 |
A dagger-like anchor drivable into a hollow wall and adapted to receive a fastener screw to hold an object adjacent the wall. The anchor is fabricated from a sheet metal blank, shaped, folded and hardened to define a head having a hole to threadably receive the screw, and a pair of normally juxtaposed flat blades aligned with the hole and extending from the head, the blades terminating in triangular sections coming to a point to penetrate the wall. The blades are each provided at offset intermediate positions with a tab that projects through a complementary slot in the other blade. When the anchor is driven into the wall so that its head lies against the outer surface of the wall, and the fastener screw is then inserted in the hole and turned to advance between the blades, the screw acts to spread the blades and their tabs apart. This causes the tabs to engage the screw to create within the body of the wall a truss whose base chords are formed by the projecting tabs engaging the screw and whose side chords by the blades, the screw then forming the central strut of the truss. The truss acts as a reverse wedge to enhance the holding power of the anchor.
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