Trench excavating and shoring apparatus

Claim 1

A ditch-digging and trenching machine comprising: support means receivable in a trench to be advanced by the cutting of a face thereof, said trench having a pair of lateral walls, said support means including a plurality of spreadable elements disposed one above another and each comprising a pair of wall-engaging shields, and respective spreading means for urging the shields of said elements apart and against said lateral walls to grip the latter; a cutter assembly adapted to be thrust against said face and including a frame extending substantially the height of said face, a worm conveyor journaled in said frame and having at least one flight provided with picks adapted to mill away said face and carry detritus therefrom to the surface, and drive means for rotating said worm conveyor. a respective piston-and-cylinder arrangement connected between each of said spreadable elements and said frame and actuatable to force said worm conveyor against said face, said drive means being disposed out of said trench above grade, each of said piston-and-cylinder arrangements being actuatable independently of the piston-and-cylinder arrangements of the other spreadable elements; and a transverse conveyor receiving detritus from said worm conveyor above grade for carrying the detritus away from the trench.