| 摘要 |
A retractable cover for use over an opening such as a swimming pool is described. The cover comprises a number i (i≥3) of supporting joist means, each joist having a top and bottom surface; an even number j (j<i) of floor section means, each having a first and second end; the first end of a 1st floor section being pivotally fixed to the top surface of a 1st joist, and the first end of the jth floor section pivotally being fixed to the top surface of the ith joist, the first ends of the 2nd...j-1th floor sections being pivotally fixed to the top surfaces of joists between said 1 st and jth joists but spaced so that there is at least one joist between each joist with a floor section fixed to its top surface; said top ends of each adjacent floor section are pivotally joined above said at least one joist so the floor sections for a continuous pivotally joined floor, wherein, when the floor is retracted each of the joists is adjacent to, or a minimal distance away from the adjacent joist(s) and the floor sections are pivoted to form an accordion pleat arrangement, and when the cover is fully extended, the joists are separated out to a maximum separation distance, d, and the floor sections lie flat over said joist to form a continuous cover over said opening. |
