Method of and apparatus for making sintered powdered metal parts

Claim 1

THAT METHOD OF MAKING A SINTERED POWDERED METAL PART WHICH COMPRISES: POSITIONING PERMABLE CERAMIC MOLDS SO AS TO DFINE A MOLD CAVITY, CHARGING SAID CAVITY WITH A SUBSTANTIALLY HOMOGENEOUS MASS OF POWDERED METAL, COMPACTING SAID MASS OF POWDERED METAL IN SAID CAVITY WITHOUT SUBSTANTIAL SEPARATION OF PARTICLES THEREOF OF DIFFERENT SIZES,PURGING AIR FROMSAID MOLDS AND SAID COMPACTED MASS OF POWDERED METAL THROUGH THE PORES OF SAID PERMEABLE MOLDS, HEATING SAID MOLDS WITH THE COMPACTED MASS OF POWDERED METAL IN THE CAVITY THEREOF IN A CONTROLLED NON-OXIDIZING SINTERING ATMOSPHERE TO AN ELEVATED TEMPRATURE SO AS TO BRING SAID MOLDS AND SUCH MASS TO A SUBSTANTIALLY UNIFORM TEMPERATURE AT OR JUST BELOW THE LOWER END OF THE SINTERING TEMPERATURE RANGE FOR SAID POWDERED METAL, GRADUALLY ANDUNIFORMLY HEATING SAID MOLDS AND SUCH MASS THROUGH THE LOWER PORTION OF SAID SINTERING TEMPERATURE RANGE FOR A TIME PERIOD SUFFICIENT TO SINTER SAID MASS AND SO THAT ALL OF SUCH MASS WILL BE UNIFORMLY SINTERED AT SUBSTANTIALLY THE SAME TEMPERATURE LEVEL AT SUBSTANTIALLY THE SAME TIME DURING SAID PERIOD, VENTING GAS FROM THE MOLD CAVITY THROUGHTHE PORES OF SAID PERMEABLE MOLDS AS THE HEATING PROCEEDS,SLOWLY COOLING SAID HOT SINTERED MASS AND MOLDS IN A NEUTRAL ATMOSPHERE, SAID METHOD BEING CHARACTERIZED IN THAT SAID MOLDS ARE MOVABLE RELATIVE TO EACH OTHER AND EXERT A YIELDING PRESSURE ON SAID MASS IN SAID MOLD CAVITY SO THATG THE ADJACENT SURFACES OF SAID MOLDS AND SUCH MASS REMAIN IN INTIMATE CONTACT WITH EACH OTHER DURING THE HEATING AND COOLING THEREOF, AND THAT SAID MOLDS HEAT AND COOL THE MASS SOLELY BY THE CONDUCTION OF HEAT THROUGH SAID MOLDS WHICH SHIELD SAID MASS FROM RADIANT HEATING AND COOLING.