Trajectory compensation for tiltable stopper-poured molten metal casting vessel

1. A casting apparatus for pouring molten metal into a sprue cup of a mold, comprising:

a vessel having a molten metal-receiving chamber generally extending between a filling end and a pouring end, said vessel including a nozzle disposed in a bottom surface of said chamber proximate to said pouring end;

a stopper cooperating with said nozzle to control a downward gravity flow of molten metal through said nozzle;

a first support for pivotably supporting said vessel to provide a horizontal tilt axis substantially coincident with said nozzle;

a second support connected to said vessel at a point away from said tilt axis and having a tilt drive for controlling a pivot position of said vessel;

a tilt angle controller detecting a level of molten metal within said chamber and engaging said tilt drive to maintain said level of said molten metal within said chamber at a generally constant head height defined between an upper surface of the molten metal and a nozzle exit of said nozzle;

a horizontal support rail for slidably supporting said vessel to provide a horizontal movement perpendicular to said tilt axis; and

a horizontal drive for controlling said horizontal movement in response to said pivot position so that a trajectory of said flow of molten metal is directed toward a substantially fixed point within said sprue cup.

2. The apparatus of claim 1 further comprising:

an inclination sensor for measuring said pivot position; and

a horizontal position controller for engaging said horizontal drive in response to said measured pivot position.

3. The apparatus of claim 1 wherein said horizontal drive is comprised of hydraulic cylinders.

4. The apparatus of claim 1 wherein said horizontal drive is comprised of motor-driven adjustment screws.

5. The apparatus of claim 1 wherein said vessel is movable parallel to said tilt axis to follow a moving mold.

6. A method of pouring molten metal into a mold comprising the steps of:

transferring molten metal into a vessel having a molten metal-receiving chamber generally extending between a filling end and a pouring end, said vessel including a nozzle disposed in a bottom surface of said chamber proximate to said pouring end, wherein a stopper cooperates with said nozzle to control a downward gravity flow of molten metal through said nozzle;

pivotally supporting said vessel to provide a horizontal tilt axis substantially coincident with said nozzle;

locating said nozzle above a sprue cup of said mold;

controlling a position of said stopper relative to said nozzle to provide a variable flow rate during filling of said mold;

controlling a tilt of said vessel to maintain a level of said molten metal within said chamber at a generally constant head height defined between an upper surface of the molten metal and a nozzle exit of said nozzle so that said step of controlling said position of said stopper need not compensate for any changes in said level of molten metal; and

horizontally sliding said vessel perpendicularly to said tilt axis in response to said controlled tilt so that a trajectory of said flow of molten metal is directed toward a substantially fixed point within said sprue cup.

7. The method of claim 6 wherein said substantially fixed point is comprised of a center point of said sprue cup.

8. The method of claim 6 wherein said sliding step is comprised of:

measuring said tilt; and

driving said vessel to a horizontal position corresponding to said measured tilt.