초록 ▼

An upper thermoforming mold is positioned above a lower thermoforming mold on a platen. The platen is provided with an array of position-controlled hydraulic cylinders. A controller drives the array of cylinders to uniformly advance the two molds together once heated sheets of thermoplastic material

An upper thermoforming mold is positioned above a lower thermoforming mold on a platen. The platen is provided with an array of position-controlled hydraulic cylinders. A controller drives the array of cylinders to uniformly advance the two molds together once heated sheets of thermoplastic material have been formed thereon. By controlling the position of each actuator, forces may be applied at different levels to the platen to bring about uniform molded parts and reduced deflection of the molds.

대표청구항 ▼

[ I claim:] [1.] A twin-sheet thermoforming apparatus comprising:a) a frame;b) an upper mold mounted for vertical movement on the frame;c) a platen mounted beneath the upper mold;d) a lower mold mounted to the platen;e) a plurality of hydraulic actuators mounted to the platen and acting on the lower

[ I claim:] [1.] A twin-sheet thermoforming apparatus comprising:a) a frame;b) an upper mold mounted for vertical movement on the frame;c) a platen mounted beneath the upper mold;d) a lower mold mounted to the platen;e) a plurality of hydraulic actuators mounted to the platen and acting on the lower mold, wherein each actuator has an extensible piston for vertically displacing the lower mold;f) a sensor mounted to each actuator for determining the position of the piston;g) a controller means for controlling the application of pressurized hydraulic fluid to the hydraulic actuators, wherein the controller means is connected in data receiving relationship to receive piston position information from the sensors, and wherein the controller means performs the additional function of controlling the actuators to uniformly advance the lower mold to drive a first means for forming a molded thermoplastic sheet on the lower mold into engagement with a second means for forming a molded thermoplastic sheet on the upper mold and thereby minimize deflection of the lower mold, the upper mold being separated from the lower mold by the intervening first means and the second means; andh) means for supplying precise quantities of hydraulic fluid including hydraulic pumps and each pump is controlled by the controller means, the pumps being incrementable by the controller means to cause a precise and repeatable advancement of the connected actuator.