Hollow stackable plastic products

Abstract

A molded thin-walled hollow, stackable plastic product, having an open top, a closed bottom and side walls; wherein the side walls include a series of circumferential sections joined by circumferential strips, with the upper of two adjacent wall sections having a greater diameter than the lower adjacent wall section to thereby define a circumferential ridge at the bottom of each upper wall section. The circumferential strip joining a pair of the wall sections is a circumferential isthmus having an isthmus distance, which is the minimum distance between the mold parts defining the isthmus, that is significantly shorter than the predominant thickness of the adjacent wall sections. The isthmuses, which are aligned at an acute angle with respect to each of the joined wall sections, improve the rigidity of the molded thin-walled hollow product. The wall sections include a plurality of spaced protruding ridges extending between adjacent circumferential strips. When the molded product is a hand-held vending cup the combination of the circumferential ridges and the spaced protruding ridges prevent burning of the fingers.

I claim: 
     
       1. A molded thin-walled hollow, .[.stackable.]. plastic product, having an open top, a closed bottom and side walls; wherein the side walls include .[.a series of circumferential strips,.]. .Iadd.at least one perimetric strip joining an upper side wall section and a lower side wall section, .Iaddend.with the upper .[.of two adjacent.]. wall .[.sections.]. .Iadd.section .Iaddend.having a minimum .[.diameter.]. .Iadd.cross-sectional area .Iaddend.greater than a maximum .[.diameter.]. .Iadd.cross-sectional area .Iaddend.of the .[.lowe adjacent.]. .Iadd.lower .Iaddend.side wall section to thereby define a .[.circumferential.]. .Iadd.perimetric .Iaddend.ridge at the bottom of .[.each.]. .Iadd.the .Iaddend.upper wall section;   wherein the .[.circumferential.]. .Iadd.perimetric .Iaddend.strip joining .[.a pair of.]. said upper and lower wall sections is a .[.circumferential.]. .Iadd.perimetric .Iaddend.isthmus having an isthmus distance which is the minimum thickness of said strip defining the isthmus, that is significantly shorter than the predominant thickness of the adjacent wall sections; and   wherein said isthmus is aligned at an acute angle with respect to each of the wall sections joined by said isthmus, with the juncture of the isthmus and the upper wall section being closer to the bottom of the product than the juncture of the isthmus and the lower wall section.   
     
     
       2. A product according to claim 1, wherein .Iadd.the side walls include a series of said perimetric strips joining a series of side wall sections and .Iaddend.the wall sections include a plurality of spaced protruding ridges extending between adjacent .[.circumferential.]. .Iadd.perimetric .Iaddend.strips. 
     
     
       3. A product according to claim 2, wherein the spaced protruding ridges radially protrude from wall section in one direction and radially protrude from a wall section adjacent thereto in the opposite direction. 
     
     
       4. A product according to claim 1, wherein the side .[.wall includes.]. .Iadd.walls include .Iaddend.a plurality of said .[.circumferential.]. .Iadd.perimetric .Iaddend.strips that are said .[.circumferential.]. .Iadd.perimetric .Iaddend.isthmuses and .[.join said circumferential.]. .Iadd.wherein each strip joins a pair of adjacent said .Iaddend.side wall sections. 
     
     
       5. A product according to claim 4, wherein .Iadd.the side walls further include a plurality of perimetric strips that join side wall sections, that are not perimetric isthmuses, and that .Iaddend.alternate .[.circumferential.]. .Iadd.with said perimetric .Iaddend.strips .Iadd.that .Iaddend.are said .[.circumferential.]. .Iadd.perimetric .Iaddend.isthmuses. 
     
     
       6. A product according to claim 4, wherein the wall sections include a plurality of spaced protruding ridges extending between adjacent .[.circumferential.]. .Iadd.perimetric .Iaddend.strips. 
     
     
       7. A product according to claim 4, wherein the isthmus distance is shorter in the .[.circumferential.]. .Iadd.perimetric .Iaddend.isthmuses that are nearer to the bottom.