Apparatus and method for forming a clamshell assembly

A die set for progressively forming a clamshell container assembly from a blank having leading and trailing portions, the die set comprising

• female die means formed to include first and second mold cavities, male die means including a first die for engaging the first mold cavity to establish a first pressing station and a second die for engaging the second mold cavity to establish a second pressing station,
• press means for providing relative movement between the male and female die means,
• first stop means for selectively blocking movement of a blank relative to the female die means to position a leading portion of a blank at the first pressing station so that one container portion of a clamshell container assembly is formed in the first mold cavity upon mating engagement of the female and male die means during a first pressing operation,
• shift means for selectively moving the leading portion of said blank relative to the female die means to conduct the leading portion of said blank past the second pressing station and the trailing portion of said blank past the first pressing station, and
• second stop means for engaging the partially formed blank following operation of the shift means to position the trailing portion of said partially formed blank at the second pressing station so that the remaining container portion of the clamshell container assembly is formed in the second mold cavity upon mating engagement with the male and female die means during a subsequent pressing operation.

A press die system for progressively converting each blank in a series of blanks moving in a downstream direction through the press die system into a clamshell assembly having interconnected first and second containers, each blank including interconnected leading and trailing portions, the press die system comprising

• a female die assembly formed to include upstream and downstream mold cavities,
• downstream control means coupled to the female die assembly for aligning a trailing portion of a selected blank moving over the female die assembly in a predetermined downstream position overlying the downstream mold cavity,
• upstream control means coupled to the female die assembly for aligning a leading portion of a succeeding blank following behind said selected blank and moving over the female die assembly in a predetermined upstream position overlying the upstream mold cavity, and
• male die means for substantially simultaneously pressing the trailing portion of the selected blank into the downstream mold cavity and the leading portion of the succeeding blank into the upstream mold cavity so that one of the first and second containers is formed in each of said selected and succeeding blanks during one pressing cycle of operation of the male die means.

A method of progressively converting each blank in a stream of moving blanks into a clamshell assembly having interconnected first and second containers, each blank including interconnected leading and trailing portions, the method comprising the steps of

• providing a die set having female die means formed to include first and second mold cavities, male die means for mateably engaging the first and second mold cavities, and press means for providing relative movement between the male and female die means,
• introducing a first blank provided in the stream of moving blnaks into the die set through a space intermediate the male and female die means,
• first aligning a leading portion of the first balnk in a predetermined ustream position intermediate the first mold cavity and the male die means to establish a first presssing station.
• first moving the male die means into mating engagement with the first mold cavity to form a first container in the leading portion of the first blank in its predetermined upstream position, thereby providing a partially formed first blank,
• conducting the partially formed first blank in a downsteam direction toward the second mold cavity,
• second aligning a trailing portion of the partially formed first blank in a predetermined downstream position intermediate the second mold cavity and the male die means to eastablish a second pressing station, and
• second moving the male die means into mating engagement with the second mold cavity to form a second container in the trailing portion of the initial blank in spaced relation to the previously formed first container so that a clamshell assembly having interconnected first and second containers is produced.