Tear-off device for opening drink cans

A tear-off opening device for a drink can comprising a tab (1) with grip device (2) for tearing off, able to place in communication an interior with an exterior of the can, by means of a corresponding opening (3), a shaped lamina (4) being positioned underneath the tab (1) and secured underneath a lid (6) for a segment (41) that partially surrounds the edge of an opening (3), whilst at least a remaining segment (42) stays free, said lamina (4) having a conformation able to vary from a first stable configuration in which, with the can closed, it is drawn up underneath the tab (1), to successive and transitory configurations that take place during an extraction of the lamina (4) through the opening (3) and to a final stable configuration in which, with the extraction completed, the lamina (4) forms a stable spout with related opening (9) whose free edges belong to the free remaining segment (42) of the lamina (4), wherein the lamina (4) is ideally composed by three parts:

• a central part (5), corresponding to the opening (3) produced by a tearing of the tab (1) and secured to an inner face of the lid (6) at least along its own segment opposite to the one corresponding to the device (2) for gripping the tab (1) itself, two lateral parts (7a, 7b), symmetrical relative to the central part (5), each secured to the inner face of the lid (6) of the can for a certain segment of their perimeter starting from the union of the central part (5);
• in said first stable configuration the lamina (4) being with its own lateral parts (7a, 7b) folded, in such a way that the free portion of their perimeter projects inwards, allowing the central part (5) of the lamina (4) to remain underneath the tab (1) itself;
• in said final stable configuration the lamina (4) having, when the extraction has been completed, at least its own portions of said lateral parts (7a, 7b) in contact against the inner face of the lid (6), whilst the spout (8) comprises a bottom constituted by the central part (5) and lateral walls constituted by the extraction portion of the lateral parts (7a, 7b), the free edges of the bottom and the lateral walls defining a contour of the opening (9) for an outflow of a drink, wherein the lateral walls (7a, 7b) of the lamina (4) have geometric interference means (13) for providing geometric interference with the lid (6), such as to prevent it from re-entering the can once extracted and to render the spout (8) stable.