| 摘要 |
An improvement for use with protective panels that buttress the walls of an excavation is in the form of a knife structure that is releasably connected to the bottom edge of a protective panel by means of a plurality of cooperative connectors. The knife structure includes first and second knife walls attached at an acute angle to form a vertex edge. When secured by the connectors, the knife structure extends coextensively along the bottom edge of the panel. The knife structure preferably includes a top wall attached between the first and second knife walls, and the top wall and the first knife wall may be at a ninety degree angle to one another. Triangularly-shaped end plates and gusset plates may be included in the knife structure. Parallel guide walls may be mounted on the top wall to form a channel adapted to receive the bottom edge of the panel, and guide posts are located in the channel to mate with holes in the lower edge of the panel, if desired. The connectors are preferably axially aligned pairs, such as lugs, and a threaded rod may engage these lugs and be fastened to mount the knife structure. This improved structure may be used for each side panel where a protective structure incorporates plurality of side panels.
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