Ditch lining apparatus

A self-propelled apparatus for extruding and forming a substantially U-shaped concrete lining within a previously dug ditch, characterized by the ability to form the concrete lining within the ditch while accurately controlling the slope of the interior bottom surface of the lining, and comprising the combination of:

• (a) prime mover means for propelling said apparatus along the ground surface, said prime mover means including a frame and a plurality of rotatable drive members supporting said frame for movement over the ground surface,
• (b) primary control means associated with said prime mover means for causing said prime mover means to follow a predetermined path of travel adjacent the ditch and to vertically adjust said frame relative to said rotatable members to maintain said frame moving at a predetermined elevation,
• (c) a hopper carried by said frame and adapted to extend downwardly into the ditch for receiving the concrete material and for directing the same into the ditch,
• (d) mold means supported on said frame and communicating with said hopper for receiving concrete material from said hopper and for molding the material into a substantially U-shaped lining within the ditch in covering relation to the bottom and sides thereof as the apparatus moves along the ground, said mold means including a forming member supported for vertical movement with respect to said frame, said forming member being substantially U-shaped in cross-section and defining with the sides and bottom of the ditch an extrusion opening through which the concrete material passes to form the U-shaped concrete lining in the ditch as said prime mover means moves along the ground, and
• (e) secondary control means associated with said forming member for vertically adjusting the same relative to said frame and independently of the level of the bottom of the ditch, said secondary control means including forming member adjustment means for varying the vertical position of said forming member relative to said hopper so that the slope of the interior bottom surface of the concrete lining is accurately controlled as said prime mover means propels said apparatus along the ground surface and adjacent the previously dug ditch.