Patent ID: 7448509

Claim:
A combination of large and small covers for a water bag, comprising: a base which is in form of a cylinder vertically provided with an extension rim around a periphery of an end of said base, a vertical wall of said base being provided with exterior threads, another end of said base being provided with a leak-proof flange, said extension rim of said base being provided with a handle; a cover of small diameter having a periphery provided with exterior threads, an upper end of said cover of small diameter being provided with an expanding rim, a top end of said cover of small diameter being provided with a switch piece; a cover of large diameter having a skirt provided with interior threads engaged with said exterior threads of said base, said cover of large diameter having a center hole with interior threads for coupling with said exterior threads of said cover of small diameter, said cover of large diameter being provided with a rough portion at an outer rim of said cover of large diameter, said outer rim of said cover of large diameter being provided with a handle; said cover of small diameter being connected to an inner ring via a connecting string, said inner ring having a diameter larger than that of said center hole of said cover of large diameter and disposed through other side of said center hole thereby preventing said cover of small diameter from being lost; and said cover of small diameter being engageable with said center hole of said cover of large diameter; and said cover of large diameter being coupled with said base which is combined with a water bag; whereby when a user intends to refill liquid to said water bag, it is only necessary to switch off said cover of small diameter, and when said user intends to clean an interior of said water bag, it is only necessary to switch off said cover of large diameter and stretch a hand inside of said water bag.