Abstract: This invention pertains to a method and machine for slip forming concrete wall structures such as median barrier walls for highways. The slip form comprises a pair of opposite side walls each of which has a skirt member retractable and extensible relative to the lower portion thereof. A top wall separate from the side walls is mounted on the machine frame between the upper portions of the side walls, and each side wall and associated skirt member is movable as a unit relative to the top wall and each skirt member is independently movable relative to an associated side wall. The side walls are adjustably supported on the machine frame for adjustment laterally of the machine frame to accommodate top walls of varying widths and the top wall is verticaly adjustable relative to the machine frame independently of the side walls.

Abstract: Apparatus for slip-forming a pipe or drainage trench including a leading cutter which is attached to the front of a prime mover for digging a trench. A following cutter is also attached to the front of the prime mover, but behind the leading cutter to thereby level off the surface of the ground along the top of the trench. A rigid concrete shaping apparatus including a portion overlying the trench also includes a rigid tubular portion which is disposed within the trench. A roll of flexible plastic material is connected to the apparatus and this plastic material is sealingly connected at one end thereof to a source of air pressure which causes the plastic to inflate to a tubular shape. This plastic is thereby maintained in an inflated condition and extends along the length of the trench to a point inside of the tubular portion of the concrete shaping apparatus, at which point the plastic is pinched by rollers to thereby maintain the pressure within the inflated portion of the flexible tube.