Sprue pin and reservoir combination

Claim 1

IN AN INVESTMENT MOLD CONTAINING INVESTMENT MATERIAL FOR THE PRODUCTION OF CASTINGS BY THE LAST WAX PROCESS, AN INTEGRAL, THERMOPLASTIC SPRUE PIN AND RESERVOIR, ONE END OF SAID SPRUE PIN SUPPORTING A WAX PATTERN AND THE OTHER END SUPPORTED BY A SUPPORTING BASE, THE WAX PATTERN AND THE PORTION OF THE SPRUE PIN AND RESERVOIR ABOVE THE SUPPORTING BASE BEING EMBEDDED IN THE INVESTMENT MATERIAL; THE THERMOPLASTIC COMPOSITION OF THE SPRUE PIN AND RESERVOIR COMBINATION BEING OF SUCH NATURE THAT IT HAS A VOLATILIZING POINT ABOVE THAT OF WAX; IT VOLATILIZES COMPLETELY BELOW THE TEMPERATURE TO WHICH THE MOLD IS HEATED IN THE MAKING OF THE CASTING; AND, THE SPRUE PIN AND RESERVOIR MADE THEREFROM IS REASONABLY RIGID; THE INTEGRAL THERMOPLASTIC SPRUE PIN AND RESERVOIR COMPRISING A HOLLOW SPRUE PIN HAVING INTERMEDIATE ITS ENDS, AN INTEGRAL BULBOUS RESERVOIR MEMBER OF A LARGER CROSS-SECTIONAL AREA THAN THAT OF THE SPRUE PIN, THE RESERVOIR BEING LOCATED ALONG THE LENGTH OF THE SPRUE PIN WITH RESPECT TO THE END OF THE SPRUE PIN TO WHICH THE WAX PATTERN IS TO BE ATTACHED, IN SUCH A MANNER, THAT WHEN USED IN THE LOST WAX PROCESS, METAL FLOWS THROUGH THE SPRUE INTO THE MOLD CAVITY AT A SUFFICIENT RATE TO PREVENT POROSITY DEVELOPING IN A CASTING FORMED IN THE MOLD CAVITY, AND WHEREIN THE METAL SPRUE MAY BE READILY CUT FROM THE CASTING.