| 摘要 |
An improved roof anchor (10) is described which includes U-bolt (24) the upper end of which extends above a slate-piece (22) to provide an attachment point for a safety harness. The legs (26, 28) of the U-bolt (24) pass through the slate-piece and sarking and extend down the sides of truss (12). The lower ends of the legs are threaded and extend through apertures on lower plate (32) to receive nuts and washers (34) to clamp plate (32) against the truss (12). An upper plate member (36, 52) is located on the upper surface of the surface of the sarking and below the slate-piece (22). Convex washers (40, 42) are attached to the upper surface of the plate member (36, 52) for engaging the underside of the slate-piece (22) and complementary washers (44, 46) are welded on legs (26, 28) whereby portions of the slate-piece around the apertures (45) are clamped between washer pairs (40, 44) and (42, 46). In the event of a fall, a force applied to the U-bolt via a harness is resisted by upper plate member (36, 52) acting on the upper face of the truss (12) and the lower plate (32) acting on the lower face of the truss (12) distributing the force along the truss so as to minimise bending movements. The attachment point can incorporate a ladder hook. Embodiments of the invention are described. |
