| 摘要 |
<p>The tennis practice net includes a pair of primary, opposite frame members; and a pair of secondary, opposite frame members. The members are disposed to define a rectangular frame. A web is elastically disposed within the frame and attached at its periphery to each membeR. Linkages pivotally attached to each frame member hold the members at right angles. Pivots at the ends of each secondary member are disposed such that increasing the spacing between the primary members swings the linkages to increase the spacing between the secondary members, to stretch the web in orthogonal directions.</p> |
