Trim in place thermoforming apparatus

Claim 1

In apparatus for repeatedly forming plastic containers having laterally extending peripheral flanges from successive portions of a generally continuous flexible plastic sheet including a forming press having mold means for forming containers from said heated, softened thermoplastic sheet portions, heated plate means within said press for heating each successive sheet portion prior to forming, means for reciprocating one of said mold means and heated plate means toward the other, sheet-advancing means for advancing each sheet portion through the press and means in the press for sealing plural areas of each sheet portion prior to forming and for reducing the thickness of the sheet portions around the periphery of each container after forming without entirely severing the containers from the sheet portion, the improvement wherein said heated plate means includes a series of adjacent forms separated from each other by spacer plates, each of said forms generally conforming in peripheral contour to that of said containers, each mold of said mold means including a cavity aligned opposite one of said forms having a surface configuration of one of said containers, said improvement further including a series of blades mounted in said plate means each of which has a relatively blunt leading end extending slightly beyond the leading surfaces of said forms for sealing and reducing the cross section of each sheet portion during each cycle of the forming press, each of said blades surrounding one of said forms in heat transfer contact therewith and being aligned opposite the periphery of one of said molds.