Extending stairs, at the hatch to an attic and the like, has mountings for the legs of the mechanism at the hatch box and hatch cover, and the return spring fitting gives a smooth deployment and limits the opening angles

摘要

The extending stairs, for access to an attic and the like, has a hatch box (50) and a swing hatch cover (51). One leg (10) of the extending mechanism is linked to the hatch box by a swivel joint (31), and a second leg (20) is linked to the first leg and the hatch cover. A mounting at the first leg is a linkage point for one end of a coil spring (59), held at the hatch box at the other end. The spring linkage point is at a gap from the swivel joint, so that the longitudinal axis of the fitted spring can intersect the rotary axis of the swivel joint without fouling, when the hatch cover is pulled open.