Closed shot die casting

A die casting apparatus comprising:

• a die having a die cavity;
• a shot sleeve having an outer wall with an axial internal bore and axially spaced apart ends, one end of said internal bore in fluid communication with said die cavity, said shot sleeve further having a filling hole formed through said outer wall adjacent the other end;
• a plunger disposed in said internal bore of said shot sleeve for reciprocating axial movement therein past said filling hole to inject molten material in said shot sleeve into said die cavity;
• a filling cylinder having an axial internal bore disposed with its axis angularly offset across the axis of said shot sleeve and spaced apart from the axis of said shot sleeve, a central extent of said filling cylinder overlapping and partially intersecting said shot sleeve at said filling opening such that the internal bores of the shot sleeve and of the filling cylinders are in fluid communication through said filling opening, said filling cylinder having an opening for the introduction of molten material into said internal bore of said filling cylinder;
• a slide valve means disposed in said internal bore of said filling cylinder for reciprocating axial movement therein between a first position in which said slide valve is withdrawn from said filling hole to allow molten material to flow from said internal bore of said filling cylinder through said filling hole into the internal bore of said shot sleeve and a second position in which said slide valve overlyingly seals said filling hole to prevent molten material from exiting said internal bore of said shot sleeve as said plunger moves past said filling hole to inject the molten material into said die cavity.

A method for closed shot die casting comprising:

• providing a shot sleeve having an axial internal bore in fluid communication with the cavity of a die;
• providing a filling cylinder axially angularly offset with respect to the axis of said shot sleeve and spaced apart from the axis of said shot sleeve with a central extent of the filling cylinder overlapping and partially intersecting the shot sleeve at a filling hole, the filling cylinder having an internal bore overlapping and partially intersecting the internal bore of the shot sleeve in fluid communication therewith through the filling hole;
• introducing molten material into the filling cylinder;
• allowing the molten material to flow from the filling cylinder through the filling hole into the internal bore of the shot sleeve to completely fill the internal bore of the shot sleeve with molten material;
• advancing a slide valve within the internal bore of the filling cylinder to overlyingly seal the filling hole;
• and
• advancing a plunger within the internal bore of the shot sleeve past the filling hole to inject the molten material into the cavity of the die.

A metal delivery system for a die casting apparatus comprising:

• a shot sleeve having an axial internal bore and a filling hole in fluid communication with said internal bore;
• a filling cylinder having an axial internal bore disposed with its axis angularly offset with respect to the axis of said shot sleeve, said filling cylinder at least partially intersecting said shot sleeve at an intersection, said filling hole formed at said intersection such that both of said internal bores are in fluid communication with each other through said filling hole, and such that molten material in said filling cylinder may pass through said filling hole into said shot sleeve and completely fill said shot sleeve, said filling cylinder further having an opening for the introduction of molten material into said internal bore of said filling cylinder;
• a slide valve disposed in said internal bore of said filling cylinder for reciprocating axial movement therein between a first position in which said filling hole is open to allow molten material to flow from said internal bore of said filling cylinder through said filling hole into the internal bore of said shot sleeve to completely fill said shot sleeve and a second position in which said slide valve is disposed at said filling hole and prevents molten material from flowing between said internal bore of said filling cylinder and said internal bore of said shot sleeve through said filling hole;
• a plunger disposed in said internal bore of said shot sleeve for reciprocating axial movement therein through said intersection;
• said slide valve formed with a void disposed in alignment with said intersection when said slide valve is in said second position, said void allowing said plunger to pass through said intersection unobstructed.

An improved metal-delivery system for a die-casting apparatus, said system comprising:

• a shot sleeve defining an elongated shot bore having an axis;
• a shot plunger reciprocable within said shot bore;
• a filling cylinder defining an elongated filling bore having an axis, said shot bore and said filling bore at least partially intersecting one another so as to be in fluid communication with one another, the axes of said shot bore and said filling bore being nonparallel;
• a slide valve reciprocable within said filling bore, said slide valve being operable between a filling position permitting molten metal to flow from said filling bore to said shot bore and a shot position prohibiting molten metal from flowing from said filling bore to said shot bore, said slide valve defining a passageway aligned with said shot bore when said slide valve is in said shot position and dimensioned to permit said shot plunger to pass therethrough, whereby said shot plunger can reciprocate past said slide valve in said shot position.