Patent ID: 8205473

Claim:
A key for use in a cylinder lock with a rotatable key plug having a profiled key way, said key comprising: an elongated key blade ( 120 ) with a relatively wide lower portion and a relatively narrow upper portion, there being a step-like transition region between the wider lower portion and the narrow upper portion, said key blade ( 120 ) having a longitudinal profile groove ( 122 ) located adjacent to said step-like transition region and extending along at least a portion of the length of the key blade, with an inner wall ( 124 ) of said groove being oriented substantially in parallel to or at a small angle, no more than 15°, to a side surface ( 123 ) of said lower portion of said key blade, said longitudinal profile groove ( 122 ) having, at a lower part thereof, an undercut portion ( 129 ) adjacent to and inside a ridge portion ( 128 ) of the key blade, the outside of said ridge portion forming a part of said side surface ( 123 ) of said lower portion of the key blade, in said relatively wide lower portion up to said step-like transition region ( 142 ), and the inside of said ridge portion facing said inner wall of said groove, said longitudinal profile groove ( 122 ) defining, at an upper part thereof, a width (w), perpendicularly to said side surface ( 123 ) of said lower portion of said key blade, between an upper wall ( 144 ) and said ridge portion ( 128 ), wherein said undercut portion ( 129 ) of said longitudinal profile groove ( 122 ), at its innermost part inside said ridge portion ( 128 ), is extended or expanded downwardly, in a direction which is substantially parallel to said side surface ( 123 ) of the key blade, into a longitudinal pocket ( 135 ) having a uniform width with opposite substantially parallel lateral wall portions ( 132 , 133 ) and a lowermost transverse end wall ( 134 ), which is substantially flat or slightly curved, and which is substantially parallel to a lower edge portion ( 127 ) of the key blade and faces upwardly in a direction being parallel to central plane (A) of the key blade towards said upper wall ( 144 ) of said longitudinal profile groove ( 122 ) with said opposite lateral wall portions ( 132 , 133 ) of said pocket ( 135 ) being substantially parallel to said side surface ( 123 ) of the flat key blade ( 120 ).