초록 ▼

A refrigerator liner of a vacuum formed plastic with a thickness of about 0.007″to 0.050″has each corner formed without crinkling when thermal insulation material is foamed against the outer surface of the liner. The non-crinkling of each corner of the refrigerator liner is accomplished through form

A refrigerator liner of a vacuum formed plastic with a thickness of about 0.007″to 0.050″has each corner formed without crinkling when thermal insulation material is foamed against the outer surface of the liner. The non-crinkling of each corner of the refrigerator liner is accomplished through forming each of the corners with a flat surface having its periphery as a circle during vacuum forming of the refrigerator liner rather than with a spherical radius. This enables the flat surface to be placed in tension when moved against a corresponding flat surface of a foam plug by the pressure produced during foaming of the foamed thermal insulation material. This results in each corner having a central portion with a convex cross section and an outer portion surrounding the central portion and concave in cross section whereby it does not appear to be crinkled.

대표청구항 ▼

A method of forming each corner of intersecting walls of a very thin structure of a vacuum formed plastic to avoid crinkling of each corner because of movement of the structure due to its thinness when pressure is applied to the outer structure of the structure during foaming of a liquid foam includ

A method of forming each corner of intersecting walls of a very thin structure of a vacuum formed plastic to avoid crinkling of each corner because of movement of the structure due to its thinness when pressure is applied to the outer structure of the structure during foaming of a liquid foam including: forming each corner of the intersecting walls of the structure with a flat surface during vacuum forming of the structure; disposing the vacuum formed structure with its inner structure in spaced relation to a foam plug having a flat surface at each corner corresponding to the flat surface at each corner of the vacuum formed structure so as to have a predetermined clearance therebetween; disposing the vacuum formed structure with its outer surface in spaced relation to a casing to form a space therebetween; and supplying a liquid foam into the space between the vacuum formed structure and the casing so that the liquid foam converts into plastic foam during foaming to adhere the plastic foam to the outer surface of the vacuum formed structure and the inner surface of the casing with the foaming pressure on the outer surface of the vacuum formed structure causing movement of the inner surface of the vacuum formed structure against the foam plug including the flat surface of each corner of the vacuum formed structure engaging the corresponding flat surface of the foam plug so that the flat surface of each corner of the vacuum formed structure is placed in tension to avoid crinkling of each corner of the vacuum formed structure.