Patent Publication Number: US-10316547-B2

Title: Locking system, key and key blank

Description:
The present invention relates to a locking system having a lock cylinder and a key; to a key for use in such a locking system; and to a key blank for manufacturing such a key. 
     A locking system can comprise a lock cylinder and a key. The lock cylinder can have a cylinder housing, a cylinder core rotatably supported in the cylinder housing and having a keyway, and a plurality of tumblers which partly project into the keyway of the cylinder core. The key can have a key bow (also called a key head) and a key shaft which extends, starting from the key bow, along a key axis in a key introduction direction and which has a shaft profile to act on the tumblers of the lock cylinder. Such a locking system can in particular comprise a plurality of keys and/or a plurality of lock cylinders, wherein provision can be made, on the one hand, that a respective key is suitable to open a plurality of different lock cylinders and wherein provision can be made, on the other hand, that a plurality of different keys can be suitable to open the same lock cylinder. 
     So that a respective key can open a respective lock cylinder, the key must first be configured with such an exact fit to the keyway of the cylinder core that at least an introduction region of its key shaft can be introduced into the keyway. The rotation of the cylinder core in the cylinder housing for opening the lock cylinder is, however, initially prevented by the tumblers which are as a rule preloaded into a position blocking the cylinder core with respect to the cylinder housing. Only when the shaft profile of the key acts on the tumblers and thus displaces them into a releasing position can the cylinder core be rotated in the cylinder housing so that the lock cylinder can be opened. 
     In this respect, the dimension by which a respective tumbler has to be displaced to achieve the releasing position can vary from tumbler to tumbler. For this purpose, different tumblers which differ, for example, in their lengths or in the size of a cut-out or in another manner and thus have respective different release positions can be inserted into the tumbler receivers which are provided in the cylinder core and in the cylinder housing. In this manner, different lock cylinders can be encoded differently with an otherwise like configuration by the fitting with different combinations of different tumblers. 
     Whether a respective key is suitable to open a lock cylinder then depends on whether the shaft profile has a suitable configuration to act on the tumblers of the lock cylinder exactly such that all the tumblers are displaced into a respective release position. The key can thus be encoded for one lock cylinder (or also for a plurality of lock cylinders) by the specific configuration of the shaft profile. The so-called secret code is therefore encoded in the shaft profile of the key in such keys. 
     The shaft profile alone is, however, not sufficient to ensure that all the tumblers are displaced into the respective releasing position. For this purpose, the shaft profile also has to be correctly aligned relative to the tumblers, in particular along the key axis or key introduction direction. A key fitting into the keyway can generally be introduced into the keyway at different depths within the keyway. The tumblers are, however, only displaced into the respective release position and thus only release the cylinder core for a rotation when the key is introduced into the keyway to the correct axial introduction depth and is thus aligned exactly relative to the tumblers such that regions of the shaft profile corresponding to a respective tumbler act on this respective tumbler. 
     It is therefore necessary to fix the correct axial introduction depth by the cooperation of the key and of the lock cylinder. The key bow, which projects out of the keyway on a completely introduced key and which is typically widened with respect to the key shaft for a better gripping of the key, can for this purpose typically form one or more abutments which abut the lock cylinder, for example, an end side of the cylinder core and/or of the cylinder housing, from the outside. Alternatively or additionally, the key tip, i.e. the end of the key shaft opposite the key bow, can also abut the end of the keyway opposite the key introduction opening. Such abutments are particularly easy to produce since only one or more simple edges have to be provided at the key bow or the key shaft only has to have a specific length. 
     However, this is accompanied by the fact that such keys can be copied relatively simply. Key blanks adapted for a respective lock system, for instance, can thus already have the required abutments at the key bow and/or a key shaft of the required length. Only the shaft profile then has to be transferred onto an initially non-profiled encoding section of the key shaft of a key blank for a key copy. This can take place in a largely automated manner in a copying machine. For this purpose, the original keys to be copied and a key blank matching it are clamped into the machine which then traces the vertical extent of the shaft profile of the original key and synchronously to this cuts the same vertical extent as a shaft profile into the encoding section of the key shaft of the key blank or drills it for dimple keys in which the shaft profile is located at the broad side or broad sides of the key shaft. 
     So that the copied shaft profile is applied axially correctly to the key blank, such a copying machine can have respective abutment surfaces at which the abutments of both the original key and of the key blank are aligned. It is achieved in this manner that the key copy produced from the key blank as a result has the same alignment of the shaft profile to the abutments as the original key. The simple copying ability of such keys reduces the security of the locking system. 
     It is therefore an object of the invention to provide a locking system, a key and a key blank which offer increased security and whose copying ability is made more difficult. 
     The object is satisfied by a locking system having the features of claim  1 . In particular, an abutment section is formed at the key shaft between the key bow and the shaft profile, said abutment section having an abutment profile i.e. a dimension difference, in the axial direction. The abutment profile comprises at least one projection aligned in the key introduction direction and an undercut formed between the projection and the shaft profile. The lock cylinder furthermore comprises a movable counter-abutment, wherein the abutment section of the key and the movable counter-abutment of the lock cylinder are advantageously arranged and configured such that, on the introduction of the key into the keyway, at least one abutment surface of the abutment section (in particular an abutment surface of the projection and/or of the undercut) abuts the movable counter-abutment of the lock cylinder and in so doing forms the only active abutment formed at the key for limiting the introduction of the key into the keyway to a correct axial introduction depth. In this respect, the projection or the undercut or both can be active as an abutment or as abutments. 
     In addition to the shaft profile, a further profile is therefore provided, namely said abutment profile at the key, which, unlike the shaft profile, does not serve to act on the tumblers in accordance with the secret code, but rather to fix the introduction depth of the key in the keyway. The fact that a section of the key shaft has a profile means in this respect that the surface contour of this section varies in its height along the extent of the respective profiled section in a direction perpendicular to the extent and in so doing increases in size at least once and decreases in size at least once. Since the shaft profile extends along the key axis, its vertical extent therefore varies in the radial direction. This can be the case, for example, in the manner of notches or dimples. The vertical extent thus varies in the axial direction in the abutment profile which is preferably aligned radially or substantially radially to the key axis. The abutment profile consequently has at least one axially aligned projection and one undercut. The vertical extent of a respective profile can be configured in different manners, for example at least sectionally constant, stepped, linear or increasing or decreasing in a different manner. The profile can be produced by simple cutting out, for example. Different means are, however, also conceivable. The projection of the abutment profile can thus, for instance, be formed as a pin or as tongue which is connected to the key shaft. 
     The provision of an abutment profile makes the copying of such a key using conventional cutting machines substantially more difficult. Since the projection is aligned in the key introduction direction and consequently the undercut is also aligned substantially axially to the key axis, the abutment profile cannot be cut out of the same direction as the shaft profile which extends axially and whose vertical extent therefore varies radially. The forming of the undercut is thus in particular not possible in a simple manner. 
     It is furthermore a major aspect of the invention that the explained abutment section does not abut an outer surface of the lock cylinder, but rather cooperates with the movable counter-abutment within the keyway. In this manner, the reference point for the axial position of the shaft profile is displaced into the cylinder core. The copying of such key using conventional copying machines which are designed for a reference point at the end side of the cylinder core is also hereby made difficult. 
     Furthermore, in accordance with the invention, it is not only the reference point which is made deeper with respect to the end side of the cylinder core, is namely displaced into the interior of the cylinder core, but a special counter-abutment is rather also provided. Instead of a static counter-abutment provided at the cylinder core itself and/or at the cylinder housing, the counter-abutment is namely configured as movable in accordance with the invention. This movability advantageously makes it possible that the introduction depth of the key can be dependent on the position of the movable counter-abutment. This can be utilized for a further increase in the security of the locking system as will be explained further below. In addition, the copying of the key is made even more difficult by such a variable reference point. Due to its movability, the counter-abutment furthermore does not hinder the sliding along of the shaft profile of the key shaft disposed upstream of the abutment section. 
     So that the cooperation of the abutment section with the movable counter-abutment can have an advantageous effect in the explained manner, it is important that the key also does not abut the lock cylinder outside the keyway and also does not abut a static element within the keyway. For otherwise at least one further reference point would be present for the axial position of the shaft profile which would again simplify the more difficult copying of the key. 
     It is therefore advantageous that the abutment section or one or more abutment surfaces of the abutment section forms the only effective abutment formed at the key for limiting the introduction of the key into the keyway to a correct axial introduction depth in order hereby to ensure the correct interaction of the shaft profile with the tumblers. However, this does not preclude the fact that in general further abutments are provided at the key, for instance in the form of exposed features which may e.g. be necessary or useful in the manufacture of the key, but which are not active as abutments when the key is introduced into the keyway. The key can additionally—for example with a so-called reversible key whose key shaft is radially symmetrical to allow an introduction of the key into the keyway in two different rotational orientations of the key—generally have further abutment sections which can equally abut the movable counter-abutment within the keyway. However, only a respective one of these abutment sections forms the active abutment, i.e. the abutment actually abutting the movable counter-abutment of the lock cylinder on the introduction of the key into the keyway. 
     In accordance with an advantageous embodiment, the movable counter-abutment is supported in the cylinder core displaceable radially to the keyway. The abutment is consequently supported displaceable radially to the key axis with a key introduced into the keyway. In this manner, the forces acting on the movable counter-abutment on the abutment of the abutment section at the movable counter-abutment are directed in a different direction (namely axially) than the direction of movability of the counter-abutment (namely radially) so that the counter-abutment is not unintentionally displaced by the abutment itself. 
     The movable counter-abutment is preferably preloaded along said radial direction toward the keyway, for example by means of a compression spring likewise received in the cylinder core. 
     The movable counter-abutment is preferably formed as one of the tumblers of the lock cylinder, in particular as the tumbler arranged closest to the key introduction opening of the keyway. No separate movable counter-abutment thus has to be provided in addition to the tumblers provided for the locking function so that the lock cylinder can be particularly simple and/or compact. The tumblers are in particular pin tumblers which have a respective core pin and a housing pin which are arranged in the releasing position of the respective pin tumbler just completely in the cylinder core or in the cylinder housing so that their common boundary surface coincides with the common boundary surface of the cylinder core and the cylinder housing and the tumbler therefore releases the cylinder core for a rotation with respect to the cylinder housing. The tumblers can, however, also be disk tumblers or other types of tumblers. 
     The movable counter-abutment can, however, alternatively also only be formed (similar to the core pin of a pin tumbler) as a cylindrical pin or the like which is displaceable radially to the keyway and is preferably preloaded in a radial direction, but without cooperating with a housing pin or otherwise having the blocking function of a pin tumbler. 
     The abutment section is preferably aligned radially, i.e. perpendicular, to the key axis. It is, however, not absolutely necessary that the abutment section or the at least one abutment surface is aligned exactly perpendicular to the key axis. It is rather sufficient that the abutment section is aligned at least sectionally substantially radial to the key axis such that it can absorb the axial forces occurring on the abutment at the movable counter-abutment without substantial radial force actions occurring by which, for instance, the preferably radially movable counter-abutment could be displaced. 
     In a preferred embodiment, the shaft profile and the abutment section are aligned at least regionally radially in the same direction relative to the key axis. The shaft profile and the abutment section can in particular substantially form an L-shape aligned in a common radial direction in a side view. When the movable counter-abutment is configured as a tumbler, such a design in particular simplifies the cooperation of both the shaft profile and of the abutment section with this tumbler. This in particular applies to keys whose shaft profile is formed as notches at a narrow side of the key shaft. In contrast, it can be advantageous with dimple keys whose shaft profile is formed as dimples at a broad side of the key shaft if the abutment section is formed at a narrow side of the key shaft, that is if the shaft profile and the abutment section are aligned radially in respective directions perpendicular to one another with respect to the key axis. 
     The key in particular has an introduction region which can be introduced into the keyway of the lock cylinder and has an outer region adjacent thereto, wherein the abutment section is formed completely within the introduction region of the key. The introduction region is consequently defined such that it—unlike said outer region of the key—is located within the keyway when the key is completely introduced into the keyway, i.e. when the key is introduced into the keyway to the correct axial introduction depth to displace all the tumblers into the respective releasing position. The introduction region of the key can, for example, have a special cross-section which corresponds to the cross-section of the keyway perpendicular to the key introduction direction. The axial extent of the introduction region with respect to the key axis in particular exactly corresponds to the correct axial introduction depth of the key which is predetermined by the cooperation of the abutment section with the movable counter-abutment. 
     It is furthermore advantageous if the abutment section of the key and the movable counter-abutment of the lock cylinder are arranged such that the key bow is spaced apart from the lock cylinder (in particular from an end side of the cylinder housing or of the cylinder core) when the key is introduced into the keyway up to the correct axial introduction depth (as is predetermined by the cooperation of the abutment section with the movable counter-abutment). The key bow is therefore in particular located completely in said outer region of the key. The key bow, which is typically radially widened with respect to the key shaft to be able to be gripped better, furthermore does not form an abutment in this manner, for instance for an end side of the lock cylinder. It is thus ensured that the key bow cannot represent any reference point for the axial position of the shaft profile which simplifies the copying of the key. 
     In accordance with an advantageous embodiment, the shaft profile is formed as an arrangement of a plurality of notches. With such notches, the vertical extent of the profile increases or decreases continuously section-wise, with all increases and/or all decreases optionally being able to take place at the same pitch angle. The tumblers can advantageously be urged into a respective position in the radial direction due to the notches with their angled flanks despite the axial introduction movement of the key with respect to the key axis. Alternatively or additionally to this, the shaft profile can also comprise an arrangement of a plurality of dimples. 
     The abutment profile is in contrast preferably formed as a step or as an arrangement of a plurality of steps (in particular two steps) in which the vertical extent of the profile is stepped, that it is sectionally constant, and changes abruptly between these sections. The steps of constant height are then in particular aligned exactly perpendicular to the axial introduction movement of the key and are therefore particularly suitable as abutment surfaces. For example, said projection can have an end side extending perpendicular to the key axis, with the base of said undercut being able to form a further end side in the sense of a bottom of the corresponding step which in particular likewise extends perpendicular to the key axis. Provided that said projection has a plurality of steps, the abutment profile can have a plurality of end sides extending perpendicular to the key axis, but offset from one another in the axial direction, with said undercut being provided between the projection and the key shaft or the shaft profile. The profile of this undercut can likewise be stepped in accordance with the plurality of steps. In general, each of these plurality of end sides of the abutment section can serve as an abutment surface for abutting the movable counter-abutment. This is, however, not absolutely necessary. It is rather sufficient—and can also be of advantage—if only a single one of a plurality of end sides of the abutment section is active as an abutment surface. 
     Said abutment surface of the abutment section can generally be provided at the projection or at the undercut, or both at the projection and at the undercut of the abutment profile. In the last-named case, in particular two or more abutment surfaces offset relative to one another are provided and are active together as the abutment. 
     The abutment profile can in particular have at least one end side which is aligned perpendicular to the key axis and which forms said abutment surface or one of a plurality of abutment surfaces for abutting the movable counter-abutment of the lock cylinder. Such an end side or abutment surface can be provided at the projection of the abutment profile, for example. Provision can alternatively or additionally be made that the undercut has at least one end side which is aligned perpendicular to the key axis (for example at the base of the undercut) and which forms an abutment surface for abutting the movable counter-abutment of the lock cylinder. 
     In accordance with a further embodiment, the abutment profile can have at least two projections. These projections can be arranged next to one another and/or aligned in parallel with one another. The projections can furthermore be of equal length or of different length. Alternatively or additionally to the at least two projections, the abutment profile can have at least two undercuts. In such an embodiment, the complexity of the abutment profile is increased. The copying of the key is thereby advantageously made more difficult. 
     In a preferred embodiment, the movable counter-abutment of the lock cylinder has a counter-profile for cooperating with the abutment profile of the key. The counter-profile is in particular configured such that it is aligned in parallel with the abutment profile with a key introduced into the keyway. A stable abutment effect is achieved in this manner. The movable counter-abutment, which is configured as a pin tumbler, for example, is preferably aligned perpendicular to the key introduction direction in this respect. The counter-profile then preferably has an extent varying in the key introduction direction. 
     The counter-profile can in particular have an annular groove or a plurality of annular grooves whose respective cross-sections can differ in their size, depth and shape when the movable counter-abutment is a pin tumbler. Such annular grooves can be produced in a constructively simple manner. 
     The counter-profile of the movable counter-abutment is preferably configured completely or only regionally (i.e. only in a part region of the projection and undercut) complementary to the abutment profile of the key. The abutment profile and the counter-profile therefore have a vertical extent in the respective region which corresponds to the inverse of the respective other one. The counter-profile has a projection, for example, where the abutment profile has an undercut, and vice versa. When the abutment profile and the counter-profile are configured completely complementary, that is can come to lie substantially seamlessly at one another, a particularly large common contact area can thereby advantageously be formed. 
     However, the profiles are not necessarily completely complementary with one another. In accordance with an advantageous embodiment, the abutment profile of the key can only be configured regionally complementary to the counter-profile of the movable counter-abutment. This can be realized, for example, in that the respective extents of the profiles correspond in quality, but not necessary also in quantity everywhere. This is the case, for example, when the position of an elevated portion in the one profile corresponds to the position of a recess in the other profile, but the height of this elevated portion does not correspond to the depth of this recess. In such an embodiment, the abutment profile does not contact the counter-profile completely flush, but only sectionally, with a key introduced into the keyway to the correct axial introduction depth. The abutment profile can, for example, only contact the counter-profile with the projection, but not with the base of the undercut, or only with the base of the undercut, but not with the projection. This has the advantage that it cannot be seen from the key alone which sections of the abutment profile actually abut the counter-profile and thus represent a reference point for the correct axial position of the shaft profile. The actual reference point can thus be masked to make a copying of the key even more difficult. Different abutment profiles and in particular different abutment surfaces at the different keys can furthermore still be used in different lock cylinders within a locking system in order thus to increase the system versatility. 
     It is in particular preferred with such an embodiment if the abutment profile is only configured regionally complementary to the counter-profile such that when the abutment section abuts the movable counter-abutment, only an end side of the projection, but not a base of the undercut set back with respect to the end side, contacts the movable counter-abutment as an abutment surface and hereby forms said only active abutment for limiting the introduction of the key to the correct axial introduction depth. The projection of the abutment section can, for example, engage into said annular groove of the movable counter-abutment and can abut a peripheral surface of the base of the annular groove, with a collar of the movable counter-abutment bounding the annular groove admittedly engaging into the undercut of the abutment section, but not contacting the base of the undercut. In other words, with such an embodiment, the projection projects further with respect to the base of the undercut than the collar of the movable counter-abutment with respect to the base of the annular groove. It is hereby particularly difficult subsequently to reproduce the abutment profile by means of manual reworking after an automatic copying of the key by means of a cutting machine since, for example, the reference point for the correct removal depth is missing when the projection is filed off. 
     It is, however, conversely possible that the abutment profile is configured only regionally complementary to the counter-profile such that when the abutment section abuts the movable counter-abutment, only a base of the undercut set back with respect to the projection, but not an end side of the projection, contacts the movable counter-abutment as an abutment surface so that only the base of the undercut of the abutment section forms said only active abutment which defines the correct axial introduction depth on the introduction of the key into the keyway. 
     Since a counter-profile is provided with which the abutment profile cooperates on the abutment of the abutment section at the movable counter-abutment, an extended secret code can be encoded. For the abutment profile and the counter-profile can be configured such that the introduction of the key is limited exactly to the correct axial introduction depth in which the key opens the lock cylinder only when the abutment profile and the counter-profile cooperate in a suitable manner—which depends on the presence of a key with the correct abutment profile for a respective lock cylinder. 
     It is preferred in this connection if the abutment profile and the counter-profile are configured such that they interlock on an abutment of the abutment section at the movable counter-abutment at least regionally (i.e. completely or only regionally). The actual interlocking in this respect depends on whether the key has the abutment profile matching the counter-profile of the movable counter-abutment. Only if this is the case is it ensured that the abutment profile and the counter-profile interlock in a correct manner. Otherwise the key abuts on the introduction into the keyway at an introduction depth in which it—despite a possible correct shaft profile—cannot open the lock cylinder due to the incorrect axial alignment of the shaft profile relative to the tumblers. This advantageously also applies to a copied key whose abutment profile does not exactly coincide with the abutment profile of the original key. 
     In accordance with an advantageous embodiment, the shaft profile is formed such that, on an introduction of the key into the keyway, the movable counter-abutment is aligned for an interlocking of the counter-profile and of the abutment profile, in particular in a direction radial to the key axis. Even if the abutment profile formed at a key and the counter-profile of the movable counter-abutment are configured to match one another, it will depend on the position of the movable abutment, for example displaceable within the cylinder core, whether the abutment profile and the counter-profile are aligned relative to one another such that they can actually interlock. On an introduction of the key into the keyway, the movable counter-abutment can be acted on, for example, by the shaft profile and can thereby change its position. If the movable counter-abutment is configured as one of the tumblers, the shaft profile can, for instance, advantageously be configured exactly with respect to the abutment profile and to the counter-profile such that the movable counter-abutment adopts that position, at the latest just before the abutment profile reaches the counter-profile, in which the abutment profile and the counter-profile can interlock with an exact fit. The security of the locking system is increased due to this complex interplay of the shaft profile, abutment profile and counter-profile and the copying of the key is made more difficult, in particular when copying without knowledge of the counter-profile of the movable counter abutment. 
     The object of the invention is also satisfied by a key for use with a lock cylinder in a locking system in accordance with one of the described embodiments. In this respect, the key can have a key bow and a key shaft which extends, starting from the key bow, along a key axis in a key introduction direction and has a shaft profile for acting on tumblers received in the lock cylinder. An abutment section can furthermore be formed between the key bow and the shaft profile, said abutment section having an abutment profile having at least one projection aligned in the key introduction direction and having an undercut formed between the projection and the shaft profile. The abutment section in particular forms the only active abutment formed at the key for limiting the introduction of the key into a keyway of the lock cylinder to a correct axial introduction depth. The advantages of such a key named above in connection with the locking system in accordance with the invention, in particular the key&#39;s more difficult copying ability, also result independently of the respective associated lock cylinder. 
     The abutment section of the key is in particular aligned radially to the key axis. The shaft profile and the abutment section can furthermore be aligned radially in the same direction or in respective directions perpendicular to one another relative to the key axis. It is furthermore preferred if the key has an introduction region which can be introduced into the keyway of the lock cylinder and an outer region which is adjacent thereto and the abutment section is formed completely within the introduction region. The abutment section of the key can have at least one abutment surface for abutting a counter-abutment of the associated lock cylinder, with the abutment surface being provided at the projection and/or at the undercut of the abutment profile. 
     The object of the invention is furthermore also satisfied by a key blank for manufacturing such a key. In this respect, the key blank has a key bow and a key shaft which extends, starting from the key bow, along a key axis in a key introduction direction and the key blank has an encoding section for forming a shaft profile for acting on tumblers received in the lock cylinder. An abutment section is furthermore formed at the key shaft between the key bow and the encoded section, said abutment section having an abutment profile having at least one projection aligned in the key introduction direction and having an undercut formed between the projection and the encoded section. This abutment section forms the only active abutment present at the key blank for limiting the introduction of a key produced from the key blank into a keyway of the lock cylinder to a correct axial introduction depth. 
     The key blank therefore substantially differs from the previously described key in that instead of the shaft profile an encoding section is provided from which the shaft profile is only formed, for example by cutting or drilling, on the manufacture of a key from the key blank. The abutment profile can in this respect have one or more of the features (singly or in combination) which were described above in connection with the abutment profile of a key in accordance with the invention or of the key of a locking system in accordance with the invention, from which the advantages named there result. 
     The abutment section of the key blank is in particular aligned radially to the key axis. The encoding section and the abutment section can furthermore be aligned radially in the same direction or in respective directions perpendicular to one another relative to the key axis. It is furthermore preferred if the key blank has an introduction region provided for introduction into the keyway of the lock cylinder and an outer region which is adjacent thereto and the abutment section is formed completely within the introduction region. The abutment section of the key blank can have at least one abutment surface for abutting a counter-abutment of the associated lock cylinder, with the abutment surface being provided at the projection and/or at the undercut of the abutment profile. 
    
    
     
       The invention will be described in more detail in the following only by way of example with reference to the drawings. 
         FIG. 1  shows an embodiment of a part of a locking system in accordance with the invention in a schematic cross-sectional view; 
         FIG. 2  shows the key of the locking system shown in  FIG. 1 ; 
         FIG. 3  shows an embodiment of the core pin of the movable counter-abutment formed as a tumbler of the lock cylinder of a locking system in accordance with the invention; 
         FIG. 4  shows the key shaft, the movable counter-abutment formed as a tumbler and a further tumbler of an embodiment of a locking system in accordance with the invention; 
         FIG. 5A  shows a key shaft, a movable counter-abutment formed as a tumbler and a further tumbler of a locking system, wherein the abutment profile of the key shaft is not configured in a suitable manner for cooperating with the counter-profile of the tumbler; 
         FIG. 5B  shows a key shaft, a movable counter-abutment formed as a tumbler and a further tumbler of a locking system, wherein the abutment profile of the key shaft matches the counter-abutment; 
         FIG. 6A  shows a key shaft, a movable counter-abutment formed as a tumbler and a further tumbler of a locking system, wherein the abutment profile of the key shaft is not configured in a suitable manner for cooperating with the counter-profile of the tumbler; 
         FIG. 6B  shows a key shaft, a movable counter-abutment formed as a tumbler and a further tumbler of a locking system, wherein the abutment profile of the key shaft matches the counter-abutment; 
         FIG. 7  shows the key shaft of an embodiment of a key in accordance with the invention; 
         FIGS. 7A to 7G  show detailed views of various embodiments of a respective abutment section corresponding to the encircled portion in  FIG. 7 ; 
         FIGS. 8A to 8C  show detailed views of a respective abutment section and of a respective movable counter-abutment configured as a tumbler of further embodiments; 
         FIG. 9  shows an embodiment of a key blank in accordance with the invention; and 
         FIG. 10  shows a key of the locking system having a shaft profile formed as at least one of a plurality of notches and a plurality of dimples. 
     
    
    
       FIG. 1  shows a substantially cylindrical cylinder core  13  and a movable counter-abutment  15  of a lock cylinder  11  of a locking system in accordance with the invention. The movable counter-abutment  15  is configured as a pin tumbler, with only the core pin thereof, but not the associated housing pin being shown. The movable counter-abutment  15  could, however, also be configured without a housing pin or also completely differently in the embodiments shown. The locking system furthermore comprises a key  17  which is shown introduced into the cylinder core  13 . The tumbler  15  is displaceably supported in the one of a plurality of tumbler receivers  21  in the cylinder core  13  closest to a key introduction opening  19  of the cylinder core  13 , and is displaceable radially to the cylinder axis Z of the cylinder core  13 . The movable counter-abutment is in this respect the first tumbler  15  of the lock cylinder  11 . Further tumblers  23  (not shown here, cf.  FIGS. 4 to 6 ) are received in the remaining tumbler receivers  21 . In this respect, the first tumbler  15  and the further tumblers  23  can be formed substantially the same, that is can have approximately the same diameter. Optionally, the movable counter-abutment  15  configured as a tumbler can, however, also differ, for instance, in its dimensions from the further tumblers  23  and can, for example, be smaller in diameter. 
     The key  17  is introduced into a keyway  25  of the cylinder core  13 . In this introduced state, the key  17  acts on the first tumbler  15  which is preloaded radially toward the keyway  25  such that the first tumbler  15  is urged radially against the preload radially outwardly into a position in which the core pin terminates flush with the cylinder core  13  and thus releases it for a rotation about its cylinder axis Z with respect to the cylinder housing, not shown, of the lock cylinder  11 . 
     As can be more clearly recognized in the individual representation of the key  17  in  FIG. 2 , the key  17  comprises a key bow  27  from where a key shaft  29  extends along the key axis S in a key introduction direction (arrow to the right). The key shaft  29  has a shaft profile  31 , which extends in parallel with the key axis S, in the form of a plurality of notches  33  in which the secret code of the key  17  is encoded and which are suitable to act on the first and the further tumblers  15 ,  23  on an introduction of the key  17  into the keyway  25  and thereby to displace them radially. 
     An abutment section  35  is formed at the key shaft  29  between the key bow  27  and the shaft profile  31 . The abutment section  35  has an abutment profile  37  in the form of a projection  39  aligned in the key introduction direction (arrow) and in the form of an undercut  41  formed between the projection  39  and the shaft profile  31  so that the abutment profile  37  is stepped (cf. in particular  FIGS. 7A to 7G ). Both the end side of the projection  39  preferably aligned perpendicular to the key axis S and the base of the undercut  41  preferably aligned perpendicular to the key axis S face in the key introduction direction and can thus serve (individually or together) as a respective abutment surface for abutting the first tumbler  15 . The abutment section  35  extends, starting from the shaft profile  31 , radially to the key axis S away from it in the same radial direction in which the shaft profile  31  is also aligned (downwardly in the Figures). In this manner, the shaft profile  31  and the abutment section  35  substantially form an L shape. 
     As is shown in  FIG. 1 , on an introduction of the key  17  into the keyway  25 , the abutment section  35  abuts the first tumbler  15  within the keyway  25  so that the introduction of the key  17  is thereby limited to the shown correct axial introduction depth at which the tumblers  15 ,  23  release the cylinder core  13  for a rotation with respect to the cylinder housing. The abutment element  35  in this respect represents an abutment of the key  17  at which otherwise no abutments are provided for abutting elements of the lock cylinder  11  and for limiting the introduction of the key  17 . 
     The key  17  has an introduction region  43  and adjacent thereto an outer region  45  which are delineated from one another by a chain-dotted line in  FIG. 2  for illustration purposes. The introduction region  43  can be introduced into the keyway  25  of the lock cylinder  11 . In contrast, the outer region  45  remains outside the keyway  25 , as can be seen in  FIG. 1 , even with a key  17  introduced into the keyway  25  to the correct axial introduction depth. In this respect, the abutment section  35  is formed completely within the introduction region  43  to be able to abut the first tumbler  15  within the keyway  25 . The key bow  27  is, in contrast, part of the outer region  45  and is moreover arranged such that it is spaced apart from the lock cylinder  11  with a key  17  introduced into the keyway  25  up to the correct axial introduction depth. 
     An embodiment of a movable counter-abutment  15  is shown in  FIG. 3  which is configured as a core pin of the first tumbler and which substantially corresponds to the embodiment shown in  FIG. 1 , but is a little longer. The core pin  15  is substantially cylindrical with an obtusely angled conical tip  47 . Separated from the tip  47  by a collar  49 , the core pin  15  has a peripheral constriction in the form of an annular groove  51 . The core pin  15  thus always has the same vertical extent independently of its rotational position within its tumbler receiver  21  (cf.  FIG. 1 ) toward the key introduction opening  19  of the keyway  25  and can in this manner form a counter-profile  53  for cooperating with the abutment profile  37  of the key  17 . 
     In this respect, the annular groove  51  and the collar  49  of the first tumbler  15  are formed to this extent complementary to the projection  39  and to the undercut  41  of the abutment profile  37  shown in  FIGS. 1 and 2  in that the widths of the projection  39  and of the annular groove  51  coincide and the widths of the undercut  41  and of the collar  49  coincide such that the projection  39  exactly fits into the annular groove  51  and the collar  49  exactly fits into the undercut  41 . In this manner, the abutment profile  37  and the counter-profile  53  interlock on an abutment of the abutment section  35  at the first tumbler  15 . However, this is only possible when the first tumbler  15  adopts the position in its tumbler receiver  21  which is correct and which is radial with respect to the cylinder axis Z, in which position the core pin  15  does not block the cylinder core  13  (cf.  FIG. 1 ). This is achieved in that the shaft profile  31  is configured accordingly and urges the core pin  15  into the shown releasing position within its tumbler receiver  21  on an introduction of the key  17  into the keyway  25 , at the latest directly before the abutment profile  37  reaches the counter-profile  53 . 
     The key shaft  29  of a key  17  in accordance with the invention and the movable counter-abutment  15  configured as a core pin of the first tumbler as well as the core pin of a further tumbler  23  are each shown in different embodiments in  FIGS. 4 to 6 . In this respect, the embodiments substantially differ by the different configuration of the abutment profile  37  and of the counter-profile  53 . The key  17  and the core pins  15 ,  23  are each shown in the position in which they are arranged when the key  17  is introduced into the keyway  25  up to the abutment of the abutment section  35  at the first tumbler  15 . 
     The abutment profile  37  of the embodiment shown in  FIG. 4  has two projections  39  and two undercuts  41  (cf. also  FIG. 7B ). The counter-profile  53  at the core pin of the first tumbler  15  is configured as two annular grooves  51  of a corresponding width with adjacent collars  49 . The two profiles  37 ,  53  are thus formed complementary to one another and can interlock. The introduction of the key  17  into the keyway  25  is thereby exactly limited to the correct axial introduction depth in which the shaft profile  31  is aligned relative to the tumblers  15 ,  23  such that it urges all the tumblers  15 ,  23  (of which only two are shown by way of example) into their releasing position. This releasing position can be recognized in  FIGS. 4 to 6  in that the end of the respective core pin  15 ,  23  opposite the tip  47  terminates exactly flush with the jacket surface  55  of the cylinder core  13  (which is only indicated by a line marking the jacket surface  55  in  FIGS. 4 to 6 ). 
     In contrast, in  FIGS. 5A and 6A , not all of the tumblers  15 ,  23  are urged into their respective releasing positions. This is due to the fact that the abutment profiles  37  of the embodiments shown in  FIGS. 5A and 6A  are not configured in a suitable manner for cooperating with the counter-profile  53  of the first tumbler  15  which corresponds to the first tumbler  15  shown in  FIG. 1 . This can have the consequence, as shown, that the abutment section  35  abuts the first tumbler  15  before the key  17  has been introduced so far into the keyway  25  that the shaft profile  31  urges all the tumblers  15 ,  23  into their respective release positions. In  FIGS. 5A and 6A , the further tumbler  23  therefore projects beyond the jacket surface  55  of the cylinder core  13  and thus prevents an opening of the lock cylinder  11 . It can be recognized from this that a part of the secret code of the locking system can also be encoded in the abutment profile  37  (or in the counter-profile  53 ) in addition to the shaft profile  31  (or the length of the core pins of the tumblers  15 ,  23 ). 
     The embodiments shown in  FIGS. 5B and 6B  differ from those in  FIGS. 5A and 6A  in that the respective counter-profile  53  of the core pin of the first tumbler  15  does not correspond to the counter-profile of the core pin  15  in  FIG. 4 , but only has an annular groove  51 . The annular groove  51  is in this respect formed in its respective axial position and width such that it exactly corresponds to the projection  39  of the respective abutment profile  37 . In other words, the respective abutment profile  37  of the key  17  in  FIGS. 5B and 6B  (as already in  FIG. 4 ) matches the respective counter-abutment  53  of the first tumbler  15  of the lock cylinder  11  and can therefore open the lock cylinder  11 . 
     Further embodiments of the abutment profile  37  in a plurality of detail views are shown by way of example in  FIGS. 7A to 7G . In this respect, the region of the key shaft  29  which is marked by the circle in  FIG. 7  and which comprises the abutment section  35  is shown magnified in each case. It can be recognized from the examples that the abutment profile  37  can differ with respect to the number of projections  39  and undercuts  41  as well as with respect to their respective positions and widths. The abutment profiles  37  are admittedly each formed as steps (with the exception of the undercut  41  in  FIG. 7F ). The abutment profiles  37  can, however, generally also differ with respect to their shapes. 
     A further embodiment is shown in  FIG. 8A  in which the abutment profile  37  of the key  17  and the counter-profile  53  of the movable counter-abutment  15  are admittedly complementary with respect to the sequence of elevated portions and recesses along the extent of the abutment element  35  radial to the key axis S (cf.  FIG. 2 ) or along the core pin axis K, but not with respect to the respective dimension of the elevated portions and recesses. For the projection  39  of the abutment profile  37  extends further forward than the annular groove  51  of the counter-profile  53  is deep. Nevertheless, the abutment profile  37  and the counter-profile  53  can interlock and can limit as an abutment the introduction of the key  17  into the keyway  25  (cf.  FIG. 1 ) to a correct axial introduction depth. Such differences from an also quantitatively exact complementary design of the abutment profile  37  and of the counter-abutment profile  53  can be used directly to mask the actual reference point active as an abutment for the correct alignment of the shaft profile  31  and thus to make a copying of the key  17  more difficult. 
     The detailed views of  FIGS. 8B and 8C  show two further embodiments in which, as in the embodiment shown in  FIG. 8A , no completely complementary configuration of the abutment profile  37  and of the counter-profile  53  is provided, but the projection  39  rather projects further than the annular groove  51  is deep so that the collar  49  does not abut the base of the undercut  41 . However, in these embodiments, the respective profiles  37 ,  53  of the abutment section  35  and of the movable counter-abutment  15  are more complex in this respect since the projection  39  does not have a constant height, but is rather of a two-step design, since a section of the projection  39  (the lower in  FIG. 8B  and the upper in  FIG. 8C ) extends further in the key introduction direction (cf.  FIG. 2 ) than the other projection  39 . The projection  39  thus has two end sides which extend perpendicular to the key axis, but are mutually offset in the axial direction. In a corresponding manner, the annular groove  51  of the counter-profile  53  is likewise configured in two steps at the movable counter-abutment  15  in a matching manner thereto. These embodiments further illustrate the variation possibilities in the design of the abutment profile  37  and of the counter-profile  53 . 
     An embodiment of a key blank  57  in accordance with the invention for manufacturing a key  17  for use with a lock cylinder  11  in a locking system is shown in  FIG. 9 . The key blank  57  substantially differs from the key  17  shown in  FIG. 2  in that it does not have any shaft profile  31  at the key shaft  29 , but rather has an encoding section  59  in its place. This encoding section  59  is provided to be provided with a shaft profile  31  in the manufacture of a key  17  from the key blank  57 . 
     The key blank  57  also has an abutment section  35  which is suitable for forming an abutment profile  37 . In the embodiment of the key blank  57  shown in  FIG. 9 , the abutment section  35  already has an abutment profile  37  with a projection  39  and an undercut  41  formed between the projection  39  and the encoding section  59 . The abutment section  35  of the key blank  57  could, however, also be blank initially, that is without an abutment profile  37  which is only formed on the manufacture of a key  17  from the key blank  57 . Provision can additionally be made that the already present abutment profile  37  has to be changed or supplemented in the manufacture of a key  17  from the key blank  57  in order to match a specific counter-profile  53  in a lock cylinder  11 . Further projections  39  and/or undercuts  41  may, for example, have to be added in the abutment section  35 . 
     Like the key  17  shown in  FIG. 2 , the key blank  57  also has an introduction region  43  which is provided for introduction into the keyway  25  of the lock cylinder  11  and it has an outer region  45  adjacent thereto. The introduction region  43  and the outer region  45  are separated from one another by a chain-dotted line in  FIG. 9 . The abutment section  35  is in this respect located in the introduction region  43 . In the introduction region  43 , and preferably only in this region and not also in the outer region  45 , the key shaft  29  of the key blank  57  can have a cross-section which differs form a simple rectangle due, for example, to longitudinal recesses formed therein, said cross-section being able to be matched to a corresponding cross-section of the keyway  25  of a lock cylinder  11  which a key  17  produced from the key blank  57  should be able to open. 
     REFERENCE NUMERAL LIST 
     
         
           11  lock cylinder 
           13  cylinder core 
           15  movable counter-abutment, core pin of the first tumbler 
           17  key 
           19  key introduction opening 
           21  tumbler receiver 
           23  core pin of a further tumbler 
           25  keyway 
           27  key bow 
           29  key shaft 
           31  shaft profile 
           33  notch 
           35  abutment section 
           37  abutment profile 
           39  projection 
           41  undercut 
           43  introduction region 
           45  outer region 
           47  tip 
           49  collar 
           51  annular groove 
           53  counter-profile 
           55  jacket surface 
           57  key blank 
           59  encoding section 
         K core pin axis 
         S key axis 
         Z cylinder axis