Lock and key combination with rotatable locking tumblers

A lock and key combination including

• a lock (200) having a cylindrical bore (202) accommodating a rotatable key plug (300) with a longitudinally extending key slot (370) for receiving a key blade (102) and at least one locking tumbler (320) arranged in said key plug for engagement with a code pattern (120) on said key blade, and
• a key (100) with said key blade,
• said at least one locking tumbler (320) having
• a key sensing portion (340), which is provided with two mutually spaced formations (341, 342) configured to engage with said code pattern (120) on said key blade,
• a body portion (330), which is rotatably journalled in a cavity (360) in said key plug, and
• a locking portion (350), which is formed on said body portion and is configured to cooperate with a locking mechanism (310) adapted to lock said key plug against rotation unless a key blade with a correctly cut code pattern is inserted into the lock,
• said two mutually spaced formations (341, 342) on said key sensing portion being located so as to define a specific rotary position of said body portion (330) upon inserting the key blade fully into the key slot, thereby releasing said locking mechanism and permitting rotation of said key plug in said cylindrical bore,
• characterized in that
• said body portion (330) of said at least one locking tumbler has two opposite, substantially flat side surfaces (331, 332) and a peripheral edge surface forming a contour,
• said cavity (360), accommodating an associated one of said at least one locking tumbler, is larger than said contour of said body portion (330) so as to permit a translatory as well as a rotary movement of said locking tumbler in a movement plane within said cavity, said movement plane being parallel to the rotary axis of said key plug (300), and
• said code pattern on said key blade comprises at least one wave-like guiding surface (120a) extending longitudinally along said key blade (102), and
• said locking tumbler (320), when the key blade is being inserted into said key slot, is caused to perform well-defined translatory as well as limited rotary movements in said movement plane,
• while being controlled by said two mutually spaced formations (341, 342), which engage with said at least one wave-like, longitudinally extending guiding surface (120a) of the key blade, and also being guided at said two opposite, substantially flat side surfaces (331, 332) by two associated walls (361, 362) of said cavity (360), so as to be retained precisely in said movement plane,
• said locking portion (350) of said at least one locking tumbler being movable, as a consequence of said translatory and rotary movements, into a final well-defined position, enabling said locking mechanism (310) to be released.