The present invention relates to a cylinder lock having a locking cylinder, known as a revolving plug, which is adapted to receive an axially insertable key. In cylinder locks of this type, the plug is provided with tumbler plates which themselves have recesses that form abutment edges which allow the key to be inserted. When a key is inserted into the plug, tumbler springs which coact with the tumbler plates cause the latter to engage a longitudinal edge of the key, the arrangement being such that only when the appropriate key has been inserted, will all of the tumbler plates be out of engagement with a recess that is provided in a stationary, non-rotatable part surrounding the plug. Thus, in conventional cylinder locks of this type, the proper key has to be inserted in order to move all of the tumbler plates out of the recess of the non-rotatable part, so that only then can the inserted key be used to turn the revolving plug.
For obvious reasons, it has been sought to build cylinder locks of the above type which are as simple and compact as possible and which at the same time provide as large a number of locking variations as possible. Thus the industry has sought to build locks of this type which, while using a minimum number of parts and as little space as possible, will provide a maximum number of locking combinations, any one of which allow the lock to be opened only with the use of the key specifically adapted to such locking combination.
It is therefore, an object of the present invention to provide a cylinder lock which is compact, which nonetheless is capable of providing a large number of locking combinations, and which can be mass-produced at low cost. Such a lock is suitable not only for general purposes, but is particularly well suited for use in the automotive field, especially as a door lock for motor vehicles. For such application, the key to the door lock must frequently serve as the ignition key as well. Moreover, the compactness is especially important in the automotive field, in view of the limited available space in which the lock must be accomodated, namely, in the space between the sheet constituting the outer panel of the door and the crank disc. In modern automotive design in particular, the available space is continually decreasing.
It is another object of the present invention to provide a cylinder lock of the above which can be used with a reversible key, i.e., a key which can be inserted into the lock in either one of two positions.