Patent ID: 9677399
Date: 2017-06-13
CPC Classifications: E21D

Claim:
1. A yieldable rock anchor, comprising: an anchor element extending along a longitudinal center axis and having a first end, a second end and an outer surface, an anchor plate attached near the first end of the anchor element, and an anchor head secured to the first end of the anchor element and adapted to clampingly engage the anchor plate, wherein the anchor element is provided, on its outer surface with a plurality of ribs, and wherein one or more sleeves for covering some of the plurality of ribs, with each sleeve having two opposing ends and being fixedly arranged on the outer surface of the anchor element such that each of the opposing ends at least substantially sealingly engages the outer surface of the anchor element, while an inner surface of each sleeve is spaced apart from the outer surface of the anchor element except at the opposing ends of each sleeve.