Description

The invention relates to a cylinder lock and key combination, wherein the lock comprises a cylinder shell, a cylinder key plug rotatably mounted in the shell, and wherein the key com¬ prises an essentially flat key blade, which is insertable into a key slot in the longitudinal direction of the cylinder key plug and which has a transversally projecting, solid base por¬ tion extending in the longitudinal direction and having side recesses for engagement with a row of side tumblers being movably mounted in the cylinder key plug.

Such a combination is known from SE-B-7906023-2 (GKN Stenman AB) , wherein a side shelf at the upper side of the solid base portion of the key blade is substantially perpendicularly ori¬ ented relative to the main plane of the key blade. Side reces¬ ses extend downwards from the side shelf for engagement with essentially circular-cylindrical side tumbler pins, which in turn engage with a side bar in the region of the shear line between the shell and cylinder key plug of the lock. The side recesses form a coded pattern with code shelfs, which define certain mutually engaging positions of the key and the side tumblers, and transitional portions therebetween, said tran¬ sitional portions being concavely curved in order to enable a movable linear contact with the end edges of the side tumblers when the key is being inserted into the key slot.

The known lock and key system has proven to function very well and has come to wide spread practical use. However, the system is subject to certain drawbacks, viz.: the key is relatively wide and heavy because of the solid base portion, which must have a substantial height (in the plane of the key blade) in order to accommodate a plurality of different levels of the

code shelfs, so that the desired number of code com¬ binations can be obtained; the key slot in the cylinder key plug is by necessi¬ ty relatively wide in the total height extension corresponding to the solid base portion of the key, which will increase the risk of unauthorized manipu¬ lation of the lock by means of picking tools.

Against this background, the object of the present invention is to achieve a lock and key combination which eliminates the above-mentioned drawbacks and which comprises a more slender key and a smaller key slot in the cylinder key plug.

This object is achieved, according to the invention, basically in that the key comprises a lip projecting upwards from the base portion and in that the key slot has a corresponding cross-sectional profile with a downwardly projecting tongue, as stated in detail in the appended claims 1, 2 and 9. Further advantageous features are stated in the other claims and in the detailed description below.

As a result of the arrangement with a longitudinal lip, which projects upwards from the solid, wider base portion of the key blade, this solid base portion can be made lower, i.e. having less vertical extension (in the plane of the key blade) , since the vertical extension of the lip can also be used for the coded side recesses. Correspondingly, the cross-sectional area of the widened lower part of the key slot will be substantial¬ ly smaller because of the downwardly projecting tongue, which fits into the space between the lip and the rest of the key blade.

The solid, wider portion of the key blade can be made even lower, if the side tumblers of the lock are non-rotatably guided or rotatable to a limited extent in the cylinder key plug and at least a part of the lower end portion of the re¬ spective side tumbler is obliquely curved into conformity with

the cylindrical shape of the cylinder key plug. Compare the claims 12 and 13.

The side recesses of the key blade may then extend practicall all the way down to the lower edge of the key blade, so that the solid, wider base portion of the key blade and the corre¬ sponding lower, widened portion of the key slot may obtain a minimal vertical extension.

In case the side tumblers are non-rotatably guided in the cylinder key plug, the number of code combinations can be further increased in that each side tumbler has an end portion or a side projection, which is specifically longitudinally displaced and which engages with the bottom surface portions of the side recesses of the key, in a corresponding manner as disclosed in the specification TJS-A-5 067 335 (Widen) . With such a code system, the establishment of a system with master keys and slave keys is facilitated.

Alternatively, the number of code combinations can be in¬ creased by making the side tumblers rotatable to a limited extent and positionable in side recesses conformed thereto in the key. The side recesses can then be specifically distribu¬ ted longitudinally and/or be obliquely positioned.

The invention also relates to a key blank according to claim 9. Such a key blank with an upwardly projecting lip, extending at the side along the rest of the key blade, is difficult to manufacture with ordinary locksmith tools. Here, it is an advantage that the manufacture must be made with a special equipment in a controlled manner, so that the distribution of key blanks can be controlled and unauthorized production of key blanks is made more difficult.

The invention will be explained further below with reference to the appended drawings illustrating three different embodi¬ ments.

Fig. la and Fig.lb illustrate in perspective views a lock and a corresponding key, respectively, according to the invention;

Fig. 2 illustrates a key having an alternative configuration of its side recesses;

Fig. 3 illustrates a key blank for making a key according to Fig. lb or 2;

Fig. 4 shows, to a larger scale, a cross-section through the lock according to Fig. la with an inserted and partially turned key;

Fig. 5 illustrates the lock according to Fig. la in a locked position (without key) ;

Fig. 6a illustrates, in a cross-sectional view, a second em¬ bodiment of a lock according to the invention;

Fig. 6b illustrates, to a larger scale, a side tumbler associ¬ ated with the lock according to Fig. 6a;

Fig. 7 illustrates, in a cross-sectional view, the lock accor¬ ding to Fig. 6a with an inserted key;

Fig. 8 illustrates, in a perspective view, a key blank for making a key associated with the lock according to Figs. 6a and 7;

Fig. 9 illustrates, in a cross-sectional view, a third embodi¬ ment of a lock according to the invention;

Fig. 10 illustrates the lock according to Fig. 9 with an in¬ serted key;

Fig. 11 illustrates, to a larger scale, a side tumbler asso¬ ciated with the lock according to Figs. 9 and 10; and

Fig. 12 is a top view of the side tumbler according to Fig. 11.

The lock and key combination illustrated in Figs, la and lb include a cylinder lock 100 and a key 200. The cylinder lock 100 consists essentially of a shell 101 and a cylinder key plug 102 being rotatable therein and having a longitudinal ke slot 103. In a conventional manner, the lock is provided with a row of central, spring loaded tumbler pins 104 with upper and lower pin portions 104a, 104b in the shell 101 and the cylinder key plug 102, respectively (cf Figs. 4 and 5), the pin portions 104b cooperating with coded V-shaped recesses 20 in the upper edge portion of the key 200.

Moroever, substantially as described in the above-mentioned specification SE-B-7906023-2, the cylinder lock 100 has a row of side tumbler pins 105, which are mounted in their entirety in holes in the cylinder key plug 102 so as to cooperate, on the one hand, with a longitudinal side bar 106, which is movable in the region between the shell 101 and the cylinder key plug 102, and, on the other hand, with coded side recesses 202 of the key 200.

When a key 200 associated with the lock has been inserted into the lock 100 and is turned around, the pin portions 104a,104b as well as the side bar 106 will clear the shear line between the cylinder key plug 102 and the shell 101 so as to release the lock.

The side recesses 202 (and 302 respectively in Fig. 2) may, e.g., be formed with planar side surface portions 203 and smoothly curved bottom surface portions 204, as illustrated in Fig. lb, or with curved, approximately part-cylindrical side surface portions 303 and planar bottom surface portions 304, as illustrated in Fig. 2 for a modified key 300 with upper recesses 301 and side recesses 302.

The keys 200,300 are made of a key blank 250 according to Fig. 3 having a cross-sectional profile fitting with a certain, required play into the key slot 103. Like the key known from the above-mentioned SE-B-7906023-2, the key blank 250 has a substantially flat, elongate blade part 251 extending in a main plane (through the lines A and B) and having a lower, solid base portion 252. The upper portion 253 of the blade part 251 is much narrower than the base portion 252 and has a substantially uniform thickness, and in this upper portion 253 the V-shaped recesses 201 and 301, respectively, are cut.

The side recesses 202 and 302, respectively, are formed in the solid, wider base portion 252 at the side surface thereof. According to the present invention, the base portion 252 has an upwardly projecting lip extending in the longitudinal direction of the key at a transversal distance from the rest of the key blade, so that a space or longitudinal groove 255 is formed between the lip 254 and the upper portion 253 of the blade part.

As will be seen from a comparision of Fig. lb, Fig. 2 and Fig. 3, the side recesses extend downwardly from the upper edge of the lip 254 and generally down to different levels in the side part of the solid base portion 252. In certain cases the side recesses 202, 302 extend only in the region of the lip 254, whereas in other cases they can extend substantially further down past the bottom of the groove 255. The side recesses 202, 302 thus extend downwardly in certain cases only through the lip 254 and in other cases also through the solid base portion 252.

The lip 254 preferably tapers upwardly and comprises, in the embodiment shown in Fig. 3, an external side surface 256, which extends in the same plane as the side surface of the solid portion 252, an upper relatively narrow surface 257 and an internal, sloping side surface 258, which extends obliquely upwardly and outwardly from the rest of the key blade.

The cross-sectional profile of the key slot 103 corresponds t the profile of the key blank 250 and thus comprises a narrow, upper portion 107 extending substantially in a plane, and a widened, lower portion 108 (corresponding to the base portion 252 of the key blank 250) . At the transition between the lowe widened portion 108 and the upper portion 107, the cylinder key plug 102 has an obliquely downwardly projecting tongue 109, which fits into the longitudinal groove 252 of the key blank 250 (and the keys 200, 300) and which substantially re- duces the size of the key slot 103.

In the embodiment illustrated in Figs, la, 2, 4 and 5, corre¬ sponding to the lock and key combination described in the above-mentioned SE-B-7906023-2 except for the lip 254 of the key and the tongue 109 of the key slot of the lock, the side tumbler pins 105 are circular-cylindrical and freely rotatable in their circular-cylindrical holes in the cylinder key plug 102. The side tumbler pins 105 will therefore not extend further down than to the level N in Fig. 5 with their lower edge portion. Consequently, the lowest side recesses 302 can¬ not be located further down than this level N, and the total vertical extension of the base portion 252 and the lip 254 will therefore be substantially greater than the maximum height of the side recesses 302 (as measured in a plane paral- lei to the main plane of the key through the lines A and B in Fig. 3).

In the embodiment according to Figs. 6a, 6b, 7 and 8, the lock 600 is substantially like the lock 100 in Figs, la, 4 and 5, thus having a rotatable cylinder key plug 602 in a shell 601 and a row of central tumbler pins 604a, 604b and side tumblers 605. However, the latter are not rotatable about their axes but have a non-circular cross-section, which substantially corresponds to the digit 8, along their total height. Compare Fig. 6b. The side tumblers 605, which cooperate with a side bar 606, have a lower obliquely curved portion 605a, the cur¬ vature of which corresponds to the cylindrical shape of the

cylinder key plug. Compare Figs. 6a and 7. Hereby, the portion of the side tumbler 605 located adjacent to the key slot 603 can extend vertically further down than the side tumbler 105 of the previous embodiment.

Consequently, the solid portion 552 of the key blank 550 (see fig. 8) can be provided with a smaller height than is the case for the key blank 250 according to Fig. 3. The finished key 500 (see Fig. 7) , i.e. with upper recesses and side recesses, may therefore be more slender and "flatter", since its solid base portion 552 has a minimal vertical extension, i.e. corre¬ sponding to the level differences desired for the side reces¬ ses. As illustrated in Figs. 7 and 8, the cross-sectional profile of the key may be provided with conventional guiding grooves 561, 562 and ridges 563.

The key slot 603 will be correspondingly narrow with a down¬ wardly projecting tongue 609 adjacent to the widened, lower portion 608, which, however, has a small vertical height in this case.

In Figs. 9 through 12 there is shown a third embodiment of a lock with a shell 801, a cylinder key plug 802, central tumbler pins (not shown), side tumblers 805, a side bar 806 and a corresponding key 700 (Fig. 10) .

The side tumblers 805 are non-rotatably guided in the cylinder key plug 802, like in the previous embodiment, but in this case they are provided with a side projection 805b, which has a limited extension vertically (in Fig. 6, the side projection 605b extends along the total height) . The side projections 805b have specifically displaced lower end portions 805c in a similar manner as described in US-A-5067335, for engagement with corresponding side recesses of the key, which are speci- fically displaced in the longitudinal direction. Hereby, the number of code combinations can be increased or, preferably, be retained in spite of fewer level differences of the side

recesses of the key. Consequently, the base portion of the ke 700 can in this case be even lower vertically, and the key slot 803 will be correspondingly smaller.

Finally, it should be pointed out that the expressions "up¬ wardly projecting", "upper", "lower", etc. refer to the orien¬ tation of the key and the lock as illustrated in the drawing figures.