Patent ID: 8721227

Claim:
A mine roof bolt comprising: an elongated rod having a first end and a second end; a protruding portion extending radially outward from the elongated rod; and a polymer coating layer covering the protruding portion and at least a portion of the elongated rod between the first and second end, the polymer coating layer comprising a plurality of tapered segments, the polymer coating layer having a first end positioned adjacent the protruding portion and a second end positioned opposite the first end of the polymer coating layer, the polymer coating layer comprising a polymeric material and having a first thickness at the protruding portion and a second thickness at a remaining portion of the elongated rod, wherein the elongated rod has a first position where the elongated rod has a predetermined axial position relative to the polymer coating layer and a second position where the elongated rod has a displaced axial position relative to the first position, the elongated rod is movable relative to the polymer coating layer from the first position to the second position in a direction extending from the first end of the polymer coating toward the second end of the polymer coating, the protruding portion and the elongated rod defining a transition between the protruding portion and the elongated rod, the transition including one of a radiused portion and a planar portion that defines a 90 degree angle between the transition and the elongated rod, and wherein, after installation, the protruding portion is configured to pull through the polymer coating layer with the elongated rod configured to move from the first position to the second position in response to dynamic loading of the mine roof bolt to absorb the dynamic loading in a controlled manner.