Dust buster filter for a vacuum cleaner

Claim 1

A dust buster filter for a vacuum cleaner comprising: a filter body made up of three layers of unwoven cloth of different thickness, said three layers of unwoven cloth sandwitching a plastic rectangular ring between the edges of every two neighboring layers, said three layers of unwoven cloth and said two plastic rings being fused together by means of a super-sonic fusing machine, the upper layer of unwoven cloth provided with four holes properly spaced apart to correspond with and fitted into by four cylindrical protrusions on the back surface of the rim of a dirt entrance; a dirt entrance being provided with a circumferential flat rim around its central opening, said rim being provided with four cylindrical protrusions to correspond with and fit into the four holes in the upper layer of unwoven cloth; and said upper layer of unwoven cloth and said rim of the dirt entrance being joined firmly with each other with hot melted glue, and said four protrusions on said rim fitting into and glued with said four holes in said upper layer of unwoven cloth by means of hot melted glue such that dirt entrance may be firmly and unseparably joined with said upper layer of unwoven cloth.