Apparatus for producing plates and similar articles

A press for the production of articles of low silhouette such as plates including:

• a mold having a cavity;
• a rigid upper pressing punch having a lower profile shaped in accordance with the interior shape of the article to be pressed and adapted for downward travel toward said cavity;
• an elastic membrane having a peripheral rim, said elastic membrane sealing the top of said cavity of said mold and secured at said rim, said membrane having a recess therein corresponding to the shape and dimensions of the article to be pressed for receiving a pulverulent porcelain composition, said membrane including an annular groove for shaping the foot of the plate, said elastic membrane having a relaxed position with a shape corresponding to the shape of the lower surface of the article, and being of substantially uniform thickness, which thickness is sufficient that it can be deformed for filling with the pulverulent material and return to its relaxed position;
• means providing a source of vacuum connected to said cavity for drawing said membrane downwardly into said cavity to position it for receipt of said pulverulent material;
• means providing a source of fluid pressure connected to said cavity for applying pressure to said membrane and the pulverulent porcelain composition on said membrane when said pressing punch is lowered on the pulverulent porcelain composition for deflecting the membrane to press the pulverulent material against said punch;
• a resiliently mounted ring surrounding said upper pressing punch, said ring seating on the membrane rim when the punch moves to closed position, said ring and said upper pressing punch having opposing contact surfaces, each of said contact surfaces having opposing grooves which together form a hollow annular cavity, a said means providing source of vacuum communicating with said annular cavity;
• an insert for the mold having means at its inner edge interfitting with the rim of said membrane;
• a securing ring for securing said insert rim in said lip, said securing ring surrounding said membrane and including a step for fitting over the peripheral portion of the upper surface of the rim of the membrane;
• fluid passage channels through said insert;
• a residual space in the top profile of the insert in the vicinity of the channels for exposing the membrane to the vacuum when the same is applied to said insert channels to draw the membrane snugly against the top profile of the insert;
• and
• said insert having outer and inner parts, said inner part being adjustable vertically and including a platen which rests against the central lower part of said membrane, thereby facilitating molding of angled sides of the article spring urging said inner part into raised position.