Patent ID: 8784522

Claim:
An air filter system ( 30 ) for the intake air of internal combustion engines, comprising: a filter housing ( 10 ); an annular filter element ( 1 ) replaceably received into a chamber within the filter housing; a secondary housing ( 20 ) secured to and closing the filter housing ( 10 ) such that the secondary housing and filter housing enclosed the filter element in the chamber therein, the secondary housing including: at least one locking element ( 22 ) operable to engage the filter housing and the filter element to lock the housing closed and lock the filter element therein; wherein the filter housing ( 10 ) is designed to internally accommodate and lock the filter element ( 1 ) therein; wherein the filter element ( 1 ) includes an end disk ( 8 ) secured onto an axial end face of the filter element ( 1 ), the end disk sealingly closing the axial end face separating a raw side from a clean side of the filter element; at least one fastening element ( 7 ), each embodied as an elongated axial protrusion ( 7 ) having a first end arranged at and secured onto a radially outer portion of the end disk ( 8 ), the elongated axial protrusion ( 7 ) elongated in an axial direction extending axially away from the end disk ( 8 ); wherein the filter housing ( 10 ) on its exterior forms a least one receptacle ( 12 ) arranged on the exterior of the filter housing and having an axially extending hole ( 12 ) extending through the receptacle and opening at opposing axial sides of the receptacle; wherein the protrusion ( 7 ) extends axially from the filter element end disk and completely through the hole and continues outwardly beyond the hole when the filter element ( 1 ) is assembled with the filter housing ( 10 ) in such a way that the filter element ( 1 ) is accommodated in the filter housing ( 10 ); wherein a portion of the axial protrusion that continues outwardly beyond the hole has a locking surface; wherein the at least one locking element ( 22 ) of the secondary housing ( 20 ) engages the at least one fastening element ( 7 ) in such a way, when the filter element ( 1 ) is accommodated in the filter housing ( 10 ) and is disposed between the filter housing ( 10 ) and the secondary housing ( 20 ), that the secondary housing ( 20 ) is detachably clamped to the filter housing ( 10 ).