초록 ▼

A high speed plastic-forming process forms a curved wall section with a compound radius along the outer edge of a sheet of plastic foam material. The process includes first die cutting the flat sheet material to a shape having an initial edge curvature, followed by securing the die cut piece to a ca

A high speed plastic-forming process forms a curved wall section with a compound radius along the outer edge of a sheet of plastic foam material. The process includes first die cutting the flat sheet material to a shape having an initial edge curvature, followed by securing the die cut piece to a carousel which passes the curved outer edge section of sheet material past heaters that controllably heat the top and bottom surfaces of the moving curved edge section. The carousel then passes the pre-heated edge section into contact with an elongated stationary curved forming shoe along the outer edge of the carousel to progressively bend the pre-heated section into a curved wall section of compound radius. The carousel then passes the formed wall section into contact with an elongated stationary curved cooling rail extending around most of the outer edge of the carousel downstream from the forming shoe. The cooling rail holds the sheet material in the curved shape while the temperature is reduced sufficiently to stabilize it in a set configuration. The heating zone length and temperature and the relative lengths of the forming shoe and cooling rail are proportioned to allow continuous feeding of die cut pieces onto the carousel, with finished parts being formed and removed after one revolution of the carousel.

대표청구항 ▼

[ We claim:] [1.] A process for fabricating plastic foam sheet material with a wall section having a compound radius, comprising the steps of:placing a generally flat piece of plastic foam sheet material on a carousel and rotating the carousel so that an exposed section of the sheet material carried

[ We claim:] [1.] A process for fabricating plastic foam sheet material with a wall section having a compound radius, comprising the steps of:placing a generally flat piece of plastic foam sheet material on a carousel and rotating the carousel so that an exposed section of the sheet material carried by the carousel travels past (a) a heating zone, (b) a forming zone, and (c) a cooling zone along an outer region of the rotating carousel,heating the exposed outer section of the sheet material to a forming temperature in the heating zone (a),thereafter bending the pre-heated section of sheet material into a wall section of a curved shape having a compound radius controlled by rotating the pre-heated section of sheet material into surface contact with a forming shoe in the forming zone (b), the forming shoe having a curved length and a curved face contacting the pre-heated section of sheet material, andthereafter transferring the formed wall section to the cooling zone (c) comprising an elongated cooling rail having a fixed curved surface positioned for surface contact with the formed wall section for holding the wall section in its curved shape while reducing the temperature of the wall section to stabilize it in the curved shape.