Invention Grant
US4679963A Playground construction 失效
游乐场施工

Playground construction
Abstract:
A playground construction comprises an earthen floor beneath the surface of the earth, a trough extending downwardly beneath the floor and having drainage means therein. The floor and trough are lined with a water pervious fabric and an aggregate of drainage stone is utilized to fill the trough and to cover an area of the floor. The fabric material has overlapping edges which are secured together thus providing an envelope for the aggregate stone. A second layer of aggregate wood fiber is placed above the enveloped stone aggregate and terminates at the surface of the earth.
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