Expansion-type anchor, sleeve used in same, and construction method

An expansion anchor comprising:

• a hollow anchor body formed with a non-expansive section and an expansive section at a portion to be inserted into a pre-formed hole in an installation region, the expansive section being expansively deformable in a direction orthogonal to an axis of the anchor body;
• an expansion actuator that is capable of expansively deforming the expansive section of the anchor body;
• and
• a sleeve that externally surrounds at least a portion of the expansive section of the anchor body,
• wherein the sleeve and the anchor body are configured to be movable relative to each other such that, when a pull-out force is exerted on the anchor body with the expansive section expanded, the sleeve is stopped in the pre-formed hole while allowing the anchor body to retreat;
• wherein the sleeve spans the expansive section and the non-expansive section of the anchor body;
• wherein the expansive section of the anchor body is formed with an axially elongated inner slit that allows the expansive section to be expansively deformable in the direction orthogonal to said axis, and
• wherein the expansion actuator comprises a group of balls arranged in the anchor body at least within the expansive section, and a bolt that forwardly pushes the group of balls.