Electric/pneumatic rim press

A press for molding an element in a mold defined by upper and lower mold parts which when closed cooperate to define a mold cavity therebetween, said press comprising a frame, an upper platen arrangement mounted on the frame and defining thereon a horizontally enlarged and downwardly facing press surface on which the upper mold part is mounted, a lower platen arrangement defining thereon a horizontally enlarged and upwardly facing press surface on which the lower mold part is mounted, at least one of said platen arrangements being vertically movable toward and away from the other platen arrangement for movement between respective closed and open positions of the mold, a drive unit drivingly connected to at least said one platen arrangement for effecting movement thereof between said open and closed positions, a mold closing device provided on a first said platen arrangement for permitting limited vertical displacement of the mold part of said first platen arrangement for displacing said last-mentioned mold part vertically toward and into closing engagement with the opposed mold part and for holding said opposed mold parts closed with a closure force, said mold closing device comprising a first gas inflatable and flexible pressure device which is mounted on said first platen arrangement and which when pressurized expands to effect vertical displacement of a booking plate which mounts the respective mold part thereon to cause the respective mold part to be vertically displaced into a closed engaged position with respect to the opposed mold part and for imposing a vertically directed closing force on the latter, and a mold cracking assist mechanism provided on said first platen arrangement, said cracking assist mechanism comprising a second gas inflatable and flexible pressure device which is mounted on said first platen arrangement and which when pressurized expands to impose a vertically directed opening force on the respective mold part to assist in effecting separation thereof from the opposed mold part.

A press for molding an element in a mold defined by upper and lower mold parts which when closed cooperate to define a mold cavity therebetween, said press comprising a frame, an upper platen arrangement mounted on said frame and defining thereon a horizontally enlarged and downwardly facing press surface on which said upper mold part is mounted, a lower platen arrangement defining thereon a horizontally enlarged and upwardly facing press surface on which said lower mold part is mounted, one of said platen arrangements being vertically movable toward and away from the other said platen arrangement for movement between respective closed and open positions of the mold, a pair of vertically elongated drive shaft units drivingly connected to said one platen arrangement for effecting movement thereof between said open and closed positions, each said drive shaft unit comprising an elongate screw shaft which extends vertically and is rotatably supported relative to said upper and lower platen arrangements and which is rotatably engaged with a nut member which surrounds said screw shaft and is mounted on said one platen arrangement, a drive mechanism connected to said screw shafts for effecting rotation thereof, and a cracking mechanism including a flexible and inflatable member provided on a first said platen arrangement which when inflated expands and imposes a vertically-directed opening force on the mold part of said first platen arrangement to effect separation of the last-mentioned mold part from the opposed mold part.