Patent ID: 10415620

Abstract:
An expansion anchor includes a hollow shaft 3 and a bolt 9 to be screwed thereinto from a base end side of the hollow shaft. The hollow shaft 3 is formed, at a portion thereof short of a tip end 3a, with a radially expansive portion 7 which includes slits 6, and a multiplicity of balls 10 are inserted into the radially expansive portion 7. When the bolt 9 is screwed, the balls 10 push against each other and move radially. As a result, the radially expansive portion 7 deforms expansively for securely engaging with a pre-formed hole 2. Even when the radially expansive portion 7 expands, stress does not concentrate at a specific portion of an installation region 1, so that it is possible to provide a high withdrawal resistance while preventing cone-type failure. The management of the withdrawal resistance can be easily performed by screwing the bolt 9) using a wrench with a torque limiter or by screwing the bolt 9 using a torque wrench.