Closure device for a container having a cylindrical opening

摘要

The invention relates to a safety closure device 1 for a container, the device including an inner and an outer cap coacting together. On initial depression of the outer cap 3 of the device when on a neck of a container, the lower (as viewed) surface of a frangible disc 18 in the outer cap bears on the upper surfaces (as viewed) of a boss 17 on the inner cap. The boss has a greater diameter than the disc 18 but a smaller diameter than a circular aperture in the outer cap 3 in which the disc 18 is situated. The boss 17 rides into the aperture when pressure is applied to the outer cap, bearing on lugs 19 and 20 holding disc 18 and rupturing them; the pressure being considerably increased where the lugs bear on the sharp edge of the boss at the transition from the uppermost surface to the boundary wall thereof. The disc 18 is released when lugs 19 and 20 rupture, to "spring" out of the aperture and away from the closure device leaving a circular hole behind. This indicates that operation of the device to remove it from the container had been effected or attempted, and the effect is enhanced by selection of different colors for the two caps. A seal 21 of the inner cap provides a can flex to accommodate to any shape of mouth of the opening, including cases where the outer edge thereof is angled or curved toward the center.