Casting apparatus and casting method

1. A casting apparatus for producing castings using molds each having a sprue, comprising

a mold-conveying means for conveying molds each containing a melt poured through said sprue;

nozzles each having a gas-introducing opening attachable to and detachable from said sprue;

a multi-axis, multi joint robot, wherein the multi-axis, multi joint robot vertically moves each nozzle to attach and detach said gas-introducing opening to and from said sprue, and wherein the multi-axis, multi joint robot engages a rail which horizontally extends above the mold-conveying means and horizontally moves following a mold conveyed by said mold-conveying means, while keeping the connection of said gas introducing opening to said sprue; and

a gas supply means connected to each nozzle for supplying a gas to said gas-introducing opening,

wherein said nozzle is connected to said multi-axis, multi joint robot, via a universal joint elastically displaceable in a direction of conveying said molds by said mold-conveying means.

2. The casting apparatus according to claim 1 , wherein a nozzle-position-detector capable of detecting the displacement of said nozzle by said universal joint is mounted to said multi-axis, multi joint robot, to control the movement of said multi-axis, multi joint robot such that the position of the nozzle detected by said nozzle-position-detector is within a predetermined range from a reference position.

3. The casting apparatus according to claim 1 , which comprises pluralities of gas supply units each constituted by a set of said nozzle and said multi-axis, multi joint robot.

4. The casting apparatus according to claim 3 , wherein said molds are successively conveyed by said mold-conveying means, and each of said gas supply units is successively operated for each of said molds.

5. The casting apparatus according to claim 1 , further comprising a melt-surface-detecting means for detecting the lowered degree of a surface of a melt poured through said sprue; said gas-introducing opening being connected to said sprue when the lowered surface level detected by said melt-surface-detecting means exceeds a threshold value.

6. A casting method for producing castings using the casting apparatus of claim 1 , comprising a step of providing the casting apparatus of claim 1 ;

a step of connecting said gas-introducing opening to a sprue of a mold into which a melt has been poured;

a step of conveying the mold to which said gas-introducing opening is connected, while introducing a gas into the mold through said gas-introducing opening; and

a step of detaching said gas-introducing opening from the sprue;

wherein in said conveying step, said gas-introducing opening connected to said sprue moves following the mold being conveyed.

7. The casting method according to claim 6 , wherein in said connecting step, said gas-introducing opening is connected to said sprue after a surface of said melt poured through said sprue is lowered to a predetermined height.

8. The casting method according to claim 6 , wherein the absolute value of acceleration of vertical vibration received by said mold is 19.6 m/s 2 or less in said conveying step.

9. The casting method according to claim 6 , wherein a reaction force generated by pushing said gas-introducing opening to said sprue for connection in said conveying step is 600 N or less.