Cap structure with elastic turnover cover

Claim 1

A snap-type cap structure made of synthetic resin, comprising: a body having a first circumferential wall; a cover having a second circumferential wall being placable on said first circumferential wall, said first and second circumferential walls being connected to each other by a first hinge having two sides; a pair of first recesses provided in the first circumferential wall, one adjacent each of said two sides of said first hinge; a pair of second recesses provided in the second circumferential wall, said second recesses being aligned with said first recesses; an elastic band fitted in each aligned set of first and second recesses, and connecting said first and second circumferential walls; wherein each of said elastic bands is connected to opposite ends of said first and second recesses through a second hinge and a third hinge at respective ends of each of said bands, with said second and third hinges being positioned at outer circumferential edges of said first and second recesses in a closed state, said elastic bands are curved into said first and second recesses from the outer circumferential edges thereof, so as to have C-shaped sections in the closed state and in a fully open state in which said cover is turned over and, the elastic bands are adapted to be non-linearly deformed from an original C-shaped section shape in the closed state through a deformed shade at an equilibrium state located between the closed state and the fully open state and then restored to the same original C-shaped section shape by elasticity at the fully open state, said deformation increasing from the closed state to the equilibrium state and decreasing from the equilibrium state to the fully open state.