Patent ID: 7513763

Claim:
A center mechanism for manipulating a bladder in a tire curing press comprising a lower plate ring adapted to carry a lower bead of the bladder, an upper plate ring adapted to carry an upper bead of the bladder, a first piston chamber, a second piston chamber positioned radially interior from said first piston chamber, an outer piston shaft operatively interconnected to said lower plate ring and received at least partially within said first piston chamber, an inner piston shaft operatively interconnected to said upper plate ring and received at least partially in said second piston chamber, an outer piston coupled to the bottom of said outer piston shaft, an inner piston coupled to the bottom of said inner piston shaft, said outer piston being adapted for reciprocating travel within said first chamber and said inner piston being adapted for reciprocating travel within said second chamber, a main port, wherein operating fluid is provided through said main port to selectively raise said outer piston shaft and said inner piston shaft, said main port being in simultaneous fluid communication with said first chamber, beneath said outer piston shaft, and said second chamber, beneath said inner piston shaft, an outer piston port in fluid communication with said first chamber above said outer piston, and an inner piston port in fluid communication with said second chamber above said inner piston, wherein said outer piston port and said inner piston port may be selectively provided with pressurized operating fluid to force said outer piston and said inner piston downward.