Vacuum molding apparatus

Claim 1

A vacuum molding apparatus having a pair of members (14, 20) moveable relative to each other under the action of a ram (18), the apparatus including a sealing ring (16) surrounding one of the members (14) that is in sealing en­gagement therewith and carries a second seal (50) for creating a seal between the two members (14, 20) during molding of the part, characterized by means (62, 64), separate from the ram (18), for breaking the seal between the upper and lower members (14, 20) of the apparatus after the part (12) has been formed.

Claim 6

An apparatus according to one of the claims 1 to 4 characterized in that said sealing ring (16) includes a plurality of air cylinders (22) normally causing piston rod (26) thereof to be fully extended, and wherein the kicker cylinders (62) provide sufficient force to partially retract the piston rods (26) of the sealing ring cylinders (22) during breaking of the seal.

Claim 7

An apparatus according to one of the claims 1 to 5 characterized in that said kicker cylinders (62) are hydraulic cylinders and the cylinders (22) of the sealing ring (16) are air cylinders.

Claim 8

An apparatus according to one of the claims 1 to 5 used for compression molding a charge into a part, said apparatus comprising a moveable upper die (14) a sealing ring (16) surrounding the upper die (14), said sealing ring (16) having a plurality of first cylinders (22) having normally downwardly extending piston rods (26) the ends of which carry a first sealing device (46) making wiping sealing engagement with an outer side surface (38) of the upper die (14), the ends of the piston rods (26) further carrying a second seal (50); a lower die (20) cooperating with the upper die (14) to form a mold cavity in the shape of the desired part (12); ram means (18) for moving the upper die (14) and sealing ring (16) downwardly until the second seal (50) abuts a fixed member (52) surrounding the lower die (20) thereby defining a vacuum chamber (54) encompassing the mold cavity; vaccum means for evacuating the vacuum chamber (54); said ram means (18) being further adapted to continue downward movement of the upper die (14) until the mold cavity is defined; and kicker cylinder means (64) surround­ing the lower die (20) and being vertically in line with a portion of the sealing ring (16), said kicker cylinder means (64) having piston rods (62) that raise upwardly to overcome the force of the sealing ring cylinders (22) to thereby break the seal provided by the second seal (50) after the part (12) has been formed thereby facili­tating quick opening of the mold.

Claim 9

A method of compression molding a part with an appara­tus according to the one of the claims 1 to 7 characterized by placing a charge on a lower die (20) of a compression molding apparatus (10); using a ram (18) to move an upper die (14) into a position wherein a seal is made between the upper and lower dies (14, 20); creating a vacuum; forming the part (12); and using a plurality of kicker cylinders (62) to break the seal between the upper and lower die (14, 20) so that the dies (14, 20) can be quickly opened.