Transition on the fly
A system is provided for varying the width of a molded concrete slab on the fly as the slab is being molded. Position and height of the paving machine relative to an external reference system are determined and controlled using at least two 3D stringless reference objects. An additional sensor provides a signal corresponding to a frame width and thus a concrete slab width, and an actuator controls the frame width actively as the paving machine advances.
1. A slipform paving machine apparatus, comprising:
a machine frame including a main frame module and at least one laterally extendable side frame member, the at least one laterally extendable side frame member being laterally extendable relative to the main frame module to vary a frame width;
at least one first side ground engaging unit and at least one second side ground engaging unit;
front and rear first side height adjustable supports supporting the machine frame from the at least one first side ground engaging unit;
at least one second side height adjustable support supporting the machine frame from the at least one second side ground engaging unit;
a variable width mold supported from the machine frame beneath the machine frame and laterally between the at least one first side ground engaging unit and the at least one second side ground engaging unit, the mold being configured to mold concrete into a concrete structure having an upper surface and lateral concrete sides as the machine moves forward in an operating direction;
at least two three-dimensional (3D) stringless reference objects configured to correspond to positions of the objects relative to an external reference system; and
a carrier frame having the at least two 3D stringless reference objects fixedly attached to the carrier frame so that a distance between the at least two 3D stringless reference objects is fixed, the carrier frame being supported from at least one of the main frame module and the at least one laterally movable side frame member.
2. The apparatus of claim 1 , wherein:
the carrier frame is fixed relative to one of the main frame module and the at least one laterally movable side frame member, and the carrier frame is movable relative to the other of the main frame module and the at least one laterally movable side frame member.
3. The apparatus of claim 2 , wherein:
the carrier frame is fixed to the at least one laterally movable side frame member; and
the machine further includes a travelling support between the carrier frame and the main frame module for supporting the carrier frame from the main frame module while allowing relative lateral movement between the carrier frame and the main frame module.
4. The apparatus of claim 1 , wherein:
the carrier frame is laterally adjustably positioned on the main frame module.
5. The apparatus of claim 1 , further comprising:
a width actuator configured to vary the frame width;
a width sensor arranged to generate a width signal corresponding to a change in the frame width; and
a controller configured to receive input signals from the 3D stringless reference objects and the width sensor, the controller also configured to control height adjustment of one or more of the side height adjustable supports and to control the width actuator so that the frame width can be varied as the machine moves forward in the operating direction.