Abstract: 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.

Abstract: A protective panel may be used alone or paired to form a protective structure to provide a protected space in an excavation by buttressing the upright walls of the excavation. The protective panel is constructed of a corrugated aluminum sheet that has alternating, oppositely opening, longitudinal channels. The end edges and the lateral edges of the sheet are rigidified respectively by a transverse and longitudinal rigidifying members. Mounting stations are located on one side of the protective panel and are formed by transverse support plates that extend across the top of a selected channel and that are reinforced by gusset webs to create a beam section. A brace assembly may mount to the mounting station and may support the protective panel against an upright excavation wall; preferably, however, a pair of opposed protective panels are interconnected and retained apart by a plurality of spreader beams extending between opposed mounting stations to create a protective structure in the form of a trench box.

Abstract: A carriage assembly for suspending and supporting trench shields in an excavated trench has an axle member that spans the trench, a wheel assembly on each end of the axle member, a pair of bracket elements on the axle member and a support member depending from each bracket element for connection to a trench shield. The wheel assemblies have wheels that rotate with respect to the bracket elements and engage the surface of the ground laterally adjacent the trench. Adjustments are provided to selectively vary the spacing of the wheels and the bracket elements.