Patent ID: 7665337

Claim:
A key for use in a cylinder lock with a rotatable key plug having a profiled keyway including a longitudinal profile rib at at least one side wall of the key way, said key comprising: an elongated, substantially flat key blade ( 120 ; 120 ′) having a longitudinal profile groove ( 122 ; 122 ′) extending along at least a portion of the length of the key blade, with a bottom wall ( 124 ; 124 ′) of said groove being substantially parallel to a side surface ( 123 ; 123 ′) of said flat key blade, said longitudinal profile groove having an undercut portion ( 129 ) adjacent to a ridge portion ( 128 , 128 ′), the outside of which forms part of a side surface ( 123 ; 123 ′) of the key blade and the inside of which comprises a side wall portion ( 126 ; 126 ′) being inclined and facing said bottom wall ( 124 ; 124 ′) of said groove, characterized in that said undercut portion ( 129 ; 129 ′) of said longitudinal profile groove is expanded, at its innermost part adjacent to said inclined side wall portion ( 126 ; 126 ′), into a longitudinally extending pocket ( 135 ; 135 ′), said pocket comprises opposite lateral walls ( 132 , 133 ) and a lowermost wall ( 134 ; 134 ′), and one of the opposite lateral walls ( 133 ; 133 ′) of said pocket forms an inside wall of said ridge portion ( 128 ; 128 ′); wherein the vertical dimension (h) of said ridge portion ( 128 ), measured in a plane of said side surface of the key blade, is more than half of the smallest width (w) of said undercut groove adjacent to said side surface, said smallest width being measured as a perpendicular projection onto said bottom wall ( 124 ) of said longitudinal groove.