Slip-forming machine and process for laying concrete mix adjacent to plastic concrete mix

A machine for laying a slab of concrete adjacent to a previously laid slab of concrete that may still be in a plastic condition, said machine comprising:

• a tractor capable of moving over the ground in a direction of advance;
• a frame mounted rigidly on the tractor and including a generally horizontal slideway;
• a hopper carried by the frame for receiving a concrete mix;
• a slip form also carried by the frame and having a top wall and spaced apart first and second side walls which are fixed in position with respect to the top wall, at least the first side wall being located beyond the side of the tractor and further being unobstructed on its outwardly presented face so that it may be brought against the edge of the previously laid slab of concrete without having the tractor move upon such previously laid slab or otherwise damaging the edge of that slab, the slip form also having an open bottom, a leading end that is connected with the hopper so that concrete mix will flow from the hopper into the slip form and an open trailing end from which the concrete mix extrudes as the tractor moves the slip form over the ground, the slip form at its leading end being supported on the frame such that it can pivot relative to the frame about a generally vertical axis, the slip form further having a slide that is located above its top wall and to the rear of the pivot axis, with the slide being engaged with the slideway on the frame such that the slip form in the region of its slide is prevented from moving upwardly or downwardly but may move laterally, whereby the trailing end of the slip form is supported by the slide;
• and force exerting means connected between the slip form and the frame for adjusting the lateral position of the trailing end of the slip form with respect to the frame and for further urging the trailing end of the slip form against the edge of the previously laid slab of concrete with substantial force, whereby the concrete which extrudes from the trailing end of the slip form forms a slab that is adjacent to the previously laid slab.

A process for laying a slab of concrete mix along a previously laid slab that is still plastic and has an edge along its side, said process comprising:

• moving a tractor along a path that is to the side of the previously laid slab, with the tractor carrying a frame and a slip form supported on the frame such that its leading end pivots relative to the frame about a vertical axis while its trailing end is free to move laterally limited distance, but is confined in the vertical direction, the slip form having spaced apart first and second side walls and a top wall extended between the side walls, the first side wall being unobstructed on its outwardly presented surface;
• introducing a concrete mix into the slip form in sufficient quantity to enable the concrete mix to extrude from the trailing end of the slip form as a slab, guiding the tractor along the path by sensing its position relative to the edge of the previously laid slab;
• and forcing the slip form laterally toward the previously laid slab so that the unobstructed outwardly presented surface of the first side wall for the slip form bears with considerable force against the edge of the previously laid slab as the concrete mix extrudes from the slip form;
• and adjusting the height of the slip form so that the concrete mix extruded from it is essentially flush with the previously laid slab.