Profiled key for cylinder locks

A key for use in a cylinder lock with a rotatable key plug having a profiled keyway. The key comprises an elongated, substantially flay key blade (120; 120′) having a longitudinal profile groove (122; 122′) extending along at least a portion of the length of the key blade. The groove has 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. The undercut portion (129; 129′) of the groove is expanded, at its innermost part adjacent to and inside said ridge portion, into a longitudinally extending pocket (135; 135′).

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a key for use in a cylinder lock with a rotatable key plug having a profiled key hole or keyway, said key comprising:an elongated, substantially flat key blade having a longitudinal profile groove extending along at least a portion of the length of the key blade, with an inner wall of said groove being substantially parallel to a side surface of said flat key blade,said longitudinal profile groove having an undercut portion adjacent to and inside a ridge portion of the key blade, the outside of said ridge portion forming a lower side surface of the key blade, at a lower part thereof,said side surface at the lower part of said key blade lying substantially in the same plane as an upper side surface of the key blade at an upper part thereof, above said longitudinal profile groove, andthe inside of said ridge portion facing said inner wall of said groove.

Such a key with an undercut groove is previously known, e.g. from U.S. Pat. No. 5,715,717 (Widén) or U.S. Pat. No. 5,640,865 (Widén). Such keys have proven to be very useful in that they provide an improved security. The key profile is quite distinguished from conventional keys, and it is rather difficult to copy such keys. Moreover, they permit a great variation of the cross-sectional profile, which is a great advantage.

OBJECT OF THE INVENTION

However, over time, there is a constant need for further distinguishing profiles and many more possible variations thereof.

A further object of the invention is to make it even more difficult to copy such profiled keys with ordinary lock smith tools.

SUMMARY OF THE INVENTION

In order to achieve these objects, the undercut longitudinal profile groove, at its innermost part inside said ridge portion, is expanded into a longitudinal pocket having opposite lateral walls and a lowermost transverse end wall, which is substantially flat or slightly curved, and one of said opposite lateral wall portions of said pocket forms an inside wall of said ridge portion, wherein the vertical dimension of said ridge portion, measured in a plane of said side surface of the key blade, is more than half of the smallest width of said undercut groove adjacent to said side surface, said smallest width being measured as a perpendicular projection onto said inner wall of said longitudinal groove. The inside wall of the ridge portion may be substantially parallel to a side surface of the key blade, so that the ridge portion forms a massive and strong material portion extending in parallel to the side surface of the key blade. The pocket inside the ridge portion may have a substantially rectangular cross-section, a substantially circular cross-section, with a relatively large curvature, or some other configuration.

In this way, the material of the key blade is used in an optimum way, and a new kind of profile is obtained, and it will be very difficult to copy such keys, especially if they are produced by stamping and milling. A cutting disc is normally not enough. Rather, it will be necessary to use broaching tools and a well-controlled use of such tools in order to secure exact dimensions of the pocket-like extension of the groove. This is of great importance for key control and high security to the end user of the key.

With such a configuration of the undercut groove, many advantages are obtained at the same time, as will be explained further below.

Other preferable features are stated in the dependent claims and will appear from the detailed description below.

BRIEF DESCRIPTION OF SOME PREFERRED EMBODIMENTS

FIGS. 1 through 5show a prior art lock and key system with a key blade having an undercut profile groove in a side surface thereof, such as the system disclosed in U.S. Pat. No. 5,715,717 (Widén). The lock10is of the kind having a housing11with a rotatable key plug12accommodated in a cylindrical bore of the housing. In the key plug12, there is a central longitudinal keyway or key hole13having a sectional profile corresponding to an associated key20provided with conventional recesses21at the upper edge thereof and a profile groove22at a side surface23of the key blade. As appears fromFIG. 3, the key also has a grip portion24.

The operation of the lock is more readily understood from the cross-sectional view inFIG. 4. The key plug12is rota-table within the housing11and can be locked against rotation by means of a longitudinal row of upper and lower locking pins14a,14b. Each pair of such locking pins can be positioned with their abutting end surfaces at the shear line between the key plug12and the housing11. In this position, as shown inFIG. 4, the key plug12is rotatable. Here, as is well-known in the art, the locking pins are positioned so as to release the lock by means of a properly cut key20.

The full profile of the key20(of prior art design) is illustrated inFIG. 5, as disclosed e.g. in the above-mentioned U.S. Pat. No. 5,715,717 (Widén). Accordingly, this prior art key has a longitudinal profile groove22extending longitudinally along the key blade at a depth which is slightly greater than half the thickness of the key blade. InFIG. 5, the central plane of the key blade is denoted “A”. The longitudinal groove22has an inner wall24and opposite walls25and26. One of these opposite walls, in particular the wall or surface26located closest to the base edge27of the key blade is undercut and extends in a plane being inclined so as to face inwardly towards the bottom wall or surface24. This lower side wall26of the undercut groove22forms an inside wall of a ridge portion28, the outside of which forms part of the above mentioned side surface23of the key blade.

The prior art key blade shown inFIGS. 2,3,4and5also has two further longitudinal grooves30and31on the other side of the key (to the left inFIG. 5).

The undercut portion29of the longitudinal groove22has many advantages, as explained in the above-mentioned U.S. Pat. No. 5,715,717 (Widén), especially with regard to increasing the number of possible profile variations, improved resistance against picking the lock and high security against unauthorized key copying.

According to the present invention and as illustrated inFIGS. 6 through 9, a further improvement resides in a modification of the undercut groove. This modification comprises an expansion or extension of the innermost part of the undercut portion of the groove122(FIG. 7) so as to form a longitudinal pocket-like configuration135. In these Figures, all reference numerals relating to the key correspond to those shown inFIG. 5, although they have been supplemented with the digit “1” before the number given inFIG. 5.

The downwardly extended pocket-like configuration135of the modified undercut groove122, is (in this particular embodiment) substantially rectangular in cross-section, with opposite lateral walls132and133being parallel to each other, and a lowermost transverse end wall134, being parallel to the lower edge surface127of the key blade and facing upwardly in the direction of the central plane A of the key blade.

The innermost lateral wall132of the pocket-like extension135adjoins with the inner wall124of the undercut groove, but is slightly displaced inwardly (away from the groove opening) so as to form a step136, whereas the opposite lateral wall133forms the inside wall of the ridge portion128, in parallel to the external side surface123of the key blade.

Thus, the surfaces123,133and132are substantially parallel to each other.

The ridge portion128is somewhat longer, measured in parallel to the central plane A of the key blade, than the prior art structure (FIG. 5). More particularly, the ridge portion128has a vertical dimension h, which is more than half of the smallest width w of the undercut groove122, this smallest width w being measured as a perpendicular projection onto the bottom wall124of the longitudinal groove122. Also, the vertical dimension h of the ridge portion128is greater than the distance d between the lowermost transverse end wall134and the lower edge surface127of the key blade. This structure is advantageous for several reasons:by varying the width, depth (in the plane A) and longitudinal extension of the pocket-like configuration, the profile shape can be varied considerably;because of the opposite lateral wall portions132,133the total width of the undercut portion of the profile groove122can be accommodated in a limited region laterally, so that the total width of the key blade can be kept rather small. It appears fromFIGS. 5 and 7that the total width of the new key blade is about the same;the corresponding tongue portion, which may form a part of a longitudinal rib150at a side wall of the key way (seeFIGS. 8 and 9), will be stronger and does not have to have a pointed or sharp end portion, as in the prior art structure (compareFIG. 4);the pocket-like extension135of the undercut portion of the groove122will make it much more difficult to make copies of such keys, since it is not sufficient to use only a cutter disk. Normally, other tools also have to be used. Accordingly it will be difficult for others than specialized manufacturers to produce such key blanks;the relatively long vertical extension of the ridge portion128, in parallel to the central plane A of the key blade, will make it possible to cut rather deep recesses in the ridge portion. Accordingly, just like in the prior art embodiment ofFIGS. 1-5, it is possible to provide many vertical levels of code recesses in this material region, seeFIG. 6. Of course, this will also facilitate lock and key systems having a very high number of code combinations.

InFIGS. 8 and 9there is shown an embodiment with a side locking tumbler105, which is guided in a cylindrical cavity106in the rotatable key plug112. In principle, the arrangement is similar to those disclosed in the U.S. Pat. Nos. 4,756,177 (Widén) and 5,715,717 (Widén).

The parts that correspond to the previous, prior art embodiment (FIG. 5) have been given the same reference numerals, with the digit “1” added before the numbers shown inFIG. 5.

Accordingly, the side tumbler105is rotatable around its cylindrical axis, so that a transversally projecting finger105awill pivot back and forth when the projecting finger105afollows a wave-like coded surface on the side of the key blade (seeFIG. 6), in this case in the ridge portion128(seeFIG. 7). When the side tumbler105is correctly positioned, a recess105bin its cylindrical surface will register with corresponding projections108aon a side bar108(FIG. 9). In this way, the side bar may move radially inwards so as to permit rotation of the key plug112.

The projecting finger105aon the side tumbler105will contact the wave-like code pattern on the side of the key blade120, as shown inFIG. 6, while pivoting back and forth and also moving vertically up and down. When the key blade is fully inserted, the various side tumbler projections105awill be located in the concavities102a,102b,102c,102d,102eand possibly also (or alternatively) onto an upper code surface portion102fat an uppermost extra code level. Such an upper, extra code level is disclosed in the published international patent application WO2005/028789 (Winloc et al).

It would be possible to provide an even deeper pocket-like extension135of the undercut portion of the profile groove, in parallel to the central vertical plane A of the key blade. Then, the number of possible code levels in the ridge portion133(seeFIGS. 6 and 7) would be larger than in prior art structures.

It should be noted that the new configuration of the undercut groove122, with the pocket-like extension135, is useful even without having a side tumbler105. Then, the ridge portion is basically continuous and does not have any cuts or codes.

Also, if at least one side tumbler is used, it does not have to be rotatable, but can be guided for elevational movement only. Furthermore, the side tumbler does not have to operate as a locking means for locking the key plug against rotation. Alternatively, it may serve only as a blocking element, which prevents incorrectly cut keys from being fully inserted into the key way13of the lock10. Such a blocking element is disclosed in a patent application being filed by the same applicant on the same day as the earliest priority date of this application.

The exact configuration or shape of the longitudinally extending pocket may be modified in various ways within the scope of the present invention. InFIG. 10, there is shown an embodiment where the inner wall124of the longitudinal profile groove122merges smoothly with the adjoining lateral wall132of the pocket-like configuration135, without any step (136inFIG. 7).

InFIG. 11, the pocket-like configuration135is similar to the one inFIG. 7, but the lowermost transverse end wall134′ is rounded or curved.

The embodiment shown inFIG. 12is similar to the one inFIG. 11, but the lowermost transverse end wall134″ is shorter (but still curved), and the inner wall124of the groove merges smoothly with the adjoining lateral wall132(as inFIG. 10).

InFIG. 13, the pocket-like configuration135′ is modified into a circular cross-section. Accordingly, in this embodiment, the lateral walls132,133and the lowermost end wall134are all formed as circular arcs merging with each other.

The embodiment shown inFIG. 14is like the one shown inFIG. 10, but the lateral wall132adjoining the inner wall124is provided with a longitudinal recess132a, which is rectangular in cross-section.

The embodiment ofFIG. 15is similar to the one ofFIG. 14, but there is also a longitudinal recess133ain the lateral wall133opposite to the longitudinal recess132a.

The embodiment inFIG. 16is similar to the one inFIG. 15, but there is a longitudinal rib133b(instead of a recess133a) opposite to the longitudinal recess132a.

The modified embodiment shown inFIG. 17comprises relatively small longitudinal recesses132c,133c,134cwith part cylindrical cross-sections in the lateral walls133and132and the lowermost end wall134, respectively. Except for these part-circular recesses, this embodiment corresponds to the one shown inFIG. 7.

The embodiments ofFIGS. 14 through 17are included to illustrate that the opposite lateral wall portions and the lowermost transverse end wall of the longitudinal pocket may be provided with irregular surface portions.

The key blade120″ shown inFIG. 18is composed of a lower part150″, which is identical or similar to the lower parts of the key blades shown inFIGS. 10-17, and an upper part151″, which is identical to the lower part150″, but turned upside down. In this way the key blade150″,151″ can be inserted either way into an associated key hole, either as shown inFIG. 18or turned upside down (the profile is then exactly the same because of the symmetry of the lower and upper parts).

Finally,FIGS. 19 through 27show modified embodiments similar to those shown inFIGS. 10 through 17. Thus, the keys321through329each have a cross-sectional profile corresponding to those shown inFIGS. 10 through 17, respectively, except that the upper part of the ridge portion228is uniformly thick, and the inside226thereof is parallel to the central plane of the key blade.

In all embodiments described above, and in the appended claims, it is assumed that the inner wall124of the longitudinal undercut groove122,122′,122″ is substantially parallel to the central plane A of the key blade and a side surface123,123′,123″ thereof. Within this definition, the inner wall may be oriented at a small angle to said central plane A, this angle being normally no more than 15.

The longitudinally extending pocket may be shorter than the length of key blade and extend along only a portion thereof.

Also, the longitudinal profile rib at the key plug may be interrupted or formed as one or more separate elements mounted in the key plug.