Abstract: An automatic molten metal injector is provided which has no rotary frictional parts and is thus durable. The injector has a furnace holding a molten metal to a predetermined level and having a first port. A fixed sleeve is provided in the furnace so as to be submerged in the molten metal and has a second port communicating with the first port. A slide sleeve having a side wall formed with a third port and a closed bottom wall is received in the fixed sleeve so as to be vertically slidable between a raised position in which the third port communicates with the second port, and a lowered position in which the third port communicates with the interior of the furnace. A piston is vertically slidably received in the slide sleeve. A drive unit individually or simultaneously raises and lowers the slide sleeve and the piston.

Abstract: An automatic molten metal supply and injection device which can prevent mixing of air into molten metal being supplied, which can reduce the possibility of explosion and the development of pores, and which makes it possible to supply molten metal irrespective of whether the molds are open or closed. The device includes a body for guiding molten metal, a sleeve having a suction port and a discharge port for opening and closing communication between a molten metal passage of the body and the suction port, a first piston axially movably mounted in the sleeve for sucking molten metal in the sleeve into a predetermined amount through the suction port and extruding the thus sucked molten metal through the discharge port, and a second piston axially movably mounted in the first piston for opening and closing the discharge port and for pressurizing molten metal being discharged through the discharge port. The first and second pistons are movable independently of each other.