초록 ▼

Rotational molding apparatus for molding a kayak and the like in a mold (12). The apparatus includes an oven (A) having an oven chamber (40). A frame (B) pivotally supports oven (A) above a ground floor (10). Mold (12) rotates about a roll axis (123) on a carriage (C) while in oven chamber (40). Ove

Rotational molding apparatus for molding a kayak and the like in a mold (12). The apparatus includes an oven (A) having an oven chamber (40). A frame (B) pivotally supports oven (A) above a ground floor (10). Mold (12) rotates about a roll axis (123) on a carriage (C) while in oven chamber (40). Oven (A) pivots about a pivot axis (72) in counter-pivotal movement. Oven pivot axis (72) is spaced a distance “d”from roll axis (123) of mold (12). This causes a pendular motion to be imparted to the mold (12). Mold (12) thus swings to and fro in an arc as oven (A) pivots. Mold (12) rotates about its roll axis (123) at the same time. A well-controlled, even distribution of plastic material in the mold occurs by this combination of motions. A desired pattern of heat distribution is applied along the length of mold (12) by a series of hot air openings (50a-50d) and a like number of openings on an opposing side of a hot air plenum (49).

대표청구항 ▼

Apparatus for rotationally molding an article in a mold having a curvature, said apparatus including an oven, heating means for supplying heated air to said oven and mold, for melting resinous material inside the mold, a carriage for carrying a mold in and out of said oven, cooling means for cooling

Apparatus for rotationally molding an article in a mold having a curvature, said apparatus including an oven, heating means for supplying heated air to said oven and mold, for melting resinous material inside the mold, a carriage for carrying a mold in and out of said oven, cooling means for cooling the mold, track means for guiding said carriage in and out of said oven, first driven means for moving said carriage in and out of said oven, and second drive means for rotating said mold carried by said carriage about a mold roll axis, wherein said apparatus comprises: frame means for supporting said oven above a floor; connector means carried by said frame means for pivotally connecting said oven to said frame means including an oven pivot axis spaced a distance above said mold roll axis; a pendulum arm defined by the distance between said oven pivot axis and said mold roll axis by which an effective pendular motion is imparted to said mold as said oven pivots in counter-pivotal motion; and third drive means for swinging said oven in said counter-pivotal motion about said pivot axis as said mold rotates about said mold roll axis inside said oven in a manner that said mold swings to and fro in a controlled arc having a curvature curved in the direction of said curvature of said mold so that dwell time during which said resinous material crosses a mid-region of the mold is increased in proportion to the arc and a prescribed distribution of plastic material may be produced within said mold.