Expansion Bolt Arcuate Edges Borehole Hold

The patent applies local quality by creating end sections with reduced wall thickness at specific locations on the expansion segments. These localized thin-walled regions are positioned to face the expansion body, allowing them to be preferentially deformed and pressed against the borehole wall with higher pressure, thereby creating stress peaks that improve anchoring without compromising the overall structural integrity of the expansion sleeve.

The patent employs curvature by forming arcuate edges (first and second edges) on the expansion segments instead of straight edges. These curved edges concentrate the contact pressure with the borehole wall at specific points along the arc, creating stress peaks that enhance penetration and friction. The arcuate shape allows for more effective distribution of expansion forces while maintaining high localized pressure for improved hold.

The patent applies segmentation by dividing the expansion sleeve into multiple expansion segments separated by slots. Each expansion segment can independently deform and expand during the anchoring process, allowing for more effective contact with the borehole wall. The segmentation is achieved while maintaining integral connection through the annular connecting section, which provides the necessary structural continuity.

The patent implements the nesting principle by having the expansion segments nested within the borehole wall during expansion. The expansion segments, with their reduced wall thickness end sections, are designed to be inserted into the borehole and then expanded outward, nesting themselves against the borehole wall to create a secure fit. The integral annular connecting section ensures that these nested segments remain structurally connected.