Safety rail apparatus

Claim 1

In combination, a structure such as a building having concrete wall portions, an elongated non-metallic tube embedded in a concrete wall of the structure adjacent an outer face thereof to confine the tube against transverse expanding deformation, said tube having walls defining an internal cavity and having a continuous longitudinal entrance slot into said cavity and being of less transverse dimension than said cavity, a block member movable longitudinally in said cavity and of greater width than said slot to prevent escape of the block member through said entrance slot, the walls of said cavity converging toward said slot whereby forces on said block directed toward said slot tend to cause lateral expansion of said tube and a terminal fitting secured to said block member and extending slidably through said slot and having means for the releasable attachment thereto of movable means to be held adjacent said concrete wall, whereby tensioning of the terminal fitting by said movable means causes the block to exert the internal expanding force on the tube, resisted by the enclosing concrete wall.