MINE ROOF OR ROCK BOLT EXPANSION ANCHOR OF THE BAIL TYPE

摘要

ABSTRACT OF THE DISCLOSUREA bail type expansion anchor for mine roofs and thelike including a threaded bolt, and expander cone nut, and an ex-pansible shell assembled together, with the shell formed from anintegral blank of sheet metal having a pair of initially flat rec-tangular leaves bent to semi-cylindrical configuration with sideedges thereof in abutment with each other to define a completecylinder and having a bail strap of U-shaped configuration extend-ing upwardly from the leaves and along side the cone nut. The boltis threaded through the cone nut with the cone nut extending be-tween the leaves of the shell, and the bail portion of the shellincludes a circular top portion having a pop-out center having aninterrupted circular periphery of slightly larger diameter thanthe bolt aligned with the bolt and connected to the remainder ofthe bail by frangible uncut attachment sections, designed to bebroken out from the bail upon predetermined rotation of the boltand form an aperture for passage of the bolt therethrough.