The invention relates to a key for operating a cylinder of a cylinder lock.

Cylinder locks and respective keys ae commonly known. Generally, a cylinder lock including a lock case having a cylinder rotatable relative to the lock case, and a number of tumblers for releasably blocking rotation of the cylinder. The lock and key are configured to interact, in particular such that inserting the key into the lock to move the tumblers to respective cylinder release positions so that the cylinder can be rotated with respect to the lock case (in particular from a first cylinder position to maintain a locked state of the lock and a second cylinder position that provides a releasing state of the lock).

One type of lock system includes a key, having a blade with two flat sides and longitudinal outer edges extending in parallel. A first of the two flat sides includes a central longitudinal groove, part of opposite inner surfaces of the groove having a rehef for operating cyhnder lock tumblers. Such a key is relatively sturdy (thick and strong) and has the benefit that is does not require a tumbler operating rehef on one of its longitudinal edges, so that the relief can be protected against external impacts (e.g. in case the key is dropped), and so that damage to clothing by the rehef (e.g. in case the key is held in a pocket of a user’s clothing) can be avoided.

Since the key is relatively sturdy, it has been found that a possibility exist that a non-matching key (that does not have a matching thumber operating relief) can be used to force or break a lock to a release position. The same holds for non-matching lock testing tools (key-like elements) that are used by lock certification test institutes (such tools have the same general shape as the key that is to be inserted into the lock). Also, in the known lock-key system, it can be difficult for a user to determine if the key has been properly inserted into the lock, i.e. to a required axial key position for turning the key to open the lock.

Sturdy keys are known is many different variants. For example, EP3321454 relates to a high-security locking device comprising a barrel lock and a sturdy flat key, having a first encryption in the form of a first groove, a second encryption in the form of a second groove, and a third encryption comprising a series of first alveoli with different depth.

W02020/001901 discloses a flat sturdy key for a cylinder lock, comprising at least one coded face extending along the longitudinal extension of the flat key. WO2015/008303 teaches a sturdy key having a slot arranged between the end of the key and a region intended for alignment with the front surface of the respective cylinder when the key is in the conditions for insertion in a cylinder.

The present invention aims to provide an improved key. In particular, the invention aims to solve or alleviate the above-mentioned problems.

According to an aspect of the invention this is achieved by the features of claim 1.

In particular, there is provided a key for operating a cylinder of a cylinder lock, the key including a blade having two flat sides and longitudinal outer edges extending in parallel, wherein a first of the two flat sides including a central longitudinal groove, part of opposite inner surfaces of the groove having a relief for operating cylinder lock tumblers, characterized in that each of the longitudinal outer edges of the blade includes a notch, defining a notched blade section there-between, the notched blade section being located at a longitudinal position between a proximal head section of the blade and the relief of the longitudinal groove.

In particular, it is preferred that a transversal cross-section of the notched blade section is significantly (i.e. at least 25%, preferably at least 35%) smaller than the transversal cross-section of an adjacent notchless blade section (the notchless section being located distally with respect to the notched blade section, and both the notched blade section and adjacent notchless blade section being located proximally with respect to the relief). In this way, good results can be achieved.

Similarly, it is preferred that a width of the notched blade section is preferably significantly (i.e. at least 25% and preferably at least 35%) smaller than a width of the (notchless, reliefless) blade section located adjacent to and distally with respect to the notched blade section.

The notches in the outer edges of the blade can provide significant local weakening of the key, at a position externally with respect to the key section (i.e. relief) that is to operate a lock. Therefore, the key is not suited or not well suited to force a non-matching lock (having one or more tumblers that can not be moved to release positions by that key) from a locked condition to an opened condition, since chances are high that the key will break and/or bend, at the weakened section between the notches, when a high torque is applied to the key (and e.g. in case the relief-section of the blade of the key has entered the lock cylinder). Still, the key remains well suited to open a matching lock, since in that case the key only has to apply a relatively low torque to tun a cylinder of the lock (when the key has moved respective tumblers to their cylinder release positions). It follows that the notched blade section provides a blade weakening section of the key.

Besides, the two notches in the parallel longitudinal edges of the key can provide visual indicators to a user of a key insertion position, improving key operation.

Also, an aspect of the invention provides a cylinder lock, including a lock case having a cylinder rotatable relative to the lock case, and a number of tumblers for releasably blocking rotation of the cylinder, the lock being configured to interact with a key according to the invention, in particular to move the tumblers to cylinder release positions when the key is inserted into a key receiving space of the cylinder, the relief of the longitudinal groove of the key in particular being configured to cooperate with the tumblers of the lock to release the cylinder so that the key can be rotated to a unlocking state after being inserted into the cylinder.

In this way, above-mentioned advantages can be achieved.

Further advantageous aspects of the invention are described in the dependent claims. The invention will now be explained in more detail with reference to the drawings, showing non-hmiting embodiments.

Figure 1A depicts a front view of an example of a key according to a first embodiment of the invention;

Figure IB depicts a back view of the key shown in Fig. 1A;

Figure 1C is a cross-section over line IC-IC of Fig. 1A, through a notched blade section;

Figure ID is a cross-section over line ID-ID of Fig. IB, through a non-notched blade section distally with respect to the notched blade section;

Figure 2A is a front view of the key of Figure 1A in a lock according to an embodiment of the invention, with the key in an idle position;

Figure 2B is a cross-section over line IIB-IIB of Figure 2A;

Figure 2C is a cross-section over line IIC-IIC of Figure 2A;

Figure 2D is a cross-section over line IID-IID of Figure 2C;

Figure 3 is similar to Figure 2C, showing the key in an unlocking position;

Figure 4 is similar to Figure 2C, showing placement of a key without notches;

Figure 5 A shows a front view of an example of a key according to a second embodiment;

Figure 5B is a cross-section over line VA-V of Figure 5A;

Figure 6 is a perspective partly opened view of part of a lock according to a second non-limiting embodiment of the invention; Figure 7 A is a perspective view of a key guiding part of the lock of

Figure 6;

Figure 7B is a front view of the key guiding part shown in Fig. 7A; and

Fig. 7C is a side view of the key guiding part shown in Fig. 7 A.

Similar or corresponding features are denoted by similar or corresponding reference signs in the present patent application.

Figures 1-2 show an example of a lock system, including a key 10 and cylinder lock 1 (the key 10 for operating a cyhnder of the cylinder lock).

As follows from Figures 1A, IB and 1C, the key 10 includes a blade 11 (usually made of one or more metals and/or alloys, e.g. stainless steel or the-like) having two (straight) flat sides 12 and longitudinal (straight) outer edges 13 extending in parallel. In particular, the outer edges and flat sides define a generally rectangular outer contour of the blade when viewed in lateral cross-section (see Fig. 1C). Also, in particular, the two flat sides 12 extend in parallel with respect to each other (and in parallel with respect to a center line of the blade), and normally with respect to the two outer edges 13. The outer edges 13, facing away from each other, can be shghtly curved viewed in cross-section (see Fig. IB). According to an embodiment, a width W of each of the flat sides (the width W in particularly being measured normally/laterally with respect to a blade center line, and measured in parallel with respect to those flat blade sides) is significantly larger than a thickness D of the outer edges (e.g. at least about 3 times larger), the thickness D in particular being measured normally with respect to said width W (and both the width W and thickness D being perpendicular with respect to a longitudinal direction of the blade). For example, the blade’s width W can be constant, viewed along a blade’s longitudinal direction, except for a notched section 13b as is explained below. The key blade 11 can include a proximal head section 11a, configured to receive a user operating torque for turning the key. The head section 11a (shown with dashed lines in Fig. 1A) can e.g. be embedded or enclosed e.g. in a cover part 21 but that is not required.

At least a first flat side 1 of the blade 11 can include a central longitudinal groove 14. The example of Figure 1 shows a key wherein both sides 12 include a central longitudinal groove 14, 18 (each longitudinal groove e.g. being defined by opposite parallel inner groove sides and a parallel groove bottom side).

Figure 5 shows another example, having a single central longitudinal groove 14’ on one side and two parallel grooves 18’ on the other side (each of the latter grooves 18’ being defined by a groove bottom side and inner groove side extending in parallel).

For example, at least one of the two flat sides 12 can include a central longitudinal groove 14, 18 part of opposite inner surfaces 14a, 18a of the groove 14, 18 having a relief 15 for operating cylinder lock tumblers 4. Preferably, at least in the first embodiment, each of the longitudinal grooves

14, 18 of the two external blade faces includes the tumbler operating relief

15.

The relief 15 can locally widen the respective longitudinal groove, in lateral direction (i.e. the relief can be provided by an array of laterally notched sections of an inner wall of the groove 14, 18). As is commonly known, the tumbler operating relief of such a key 10 is shaped to operate all tumblers of a matching lock to move those tumblers to respective lock releasing positions once the key has been inserted into the lock. A said longitudinal groove 14, 18 can include an outwardly widening, e.g. tapered, section at a distal tip of the blade (see Fig. 1A).

Advantageously, each of the longitudinal outer edges 13 of the blade 11 includes a notch 13a, defining a notched blade section lib there between, the notched blade section 1 lb being located at a longitudinal position between the proximal head section 11a of the blade 11 and the relief 15 of the longitudinal groove 14, 18. In this way, a significant local weakening of the key 10 is obtained, at a position externally with respect to the section that contains the relief 15. For example, the blade’s width W can be the same at both a proximal and distal edge/end of the notches 13a (i.e. of the notched blade section 13b), viewed along a blade’s longitudinal direction (see Figures 1A, IB).

Good results can be achieved in case a transversal cross-section of the notched blade section lib (i.e. a respective area of that cross-section, shown hatched in Fig. ID) is at least 25% smaller (preferably at least 35% smaller, for example at least 40% smaller) than the transversal cross-section (i.e. a respective area of that cross-section, shown hatched in Fig. 1C) of a blade section that is located adjacent to the notched blade section lib (and proximal with respect to the relief 15). In other words, the blade 11 can have at least 25% less blade material when viewed in the former cross-section compared to the blade 11 viewed in the latter cross-section (the latter cross- section being near/adjacent to the first cross-section, and being distally with respect to the first cross-section, i.e. being located between the relief 15 containing section of the blade and the notched section of the blade when viewed in blade’s longitudinal direction).

For example, regarding the embodiment shown in Figure 1, a transversal cross-section of the notched blade section 1 lb can be smaller than 15 mm ² , and for example larger than 10 mm ² , the cross-section preferably being in the range of 11-13 mm ² .

Also, for example, a transversal cross-section of the adjacent (n on- notched) blade section can be at least about 20 mm ² , for example in the range of 20-30 mm ² , (more particularly 20-22 mm ² ).

Also, a depth H of each of the notches 13a that define the notched blade section lib can be at least 1 mm, which is a significant depth providing significant blade weakening. An axial length of each of the notches 13a (i.e. measured in parallel with respect to a center line of the key) is preferably relatively small, and can e.g. be about 1-2 mm, preferably about 1 mm, or a different length (e.g. longer than 2 mm). For example, the two opposite notches 13a can locally reduce a width of the blade by at least 25% (in particular such that the width is at least reduced with respect to an adjacent non-notched blade section located distally with respect to the notched blade section lib, i.e. longitudinally between the notched section lib and a rehef 15 containing blade section, as follows from the drawings).

A local width V of the blade between the notches 13a can e.g. be at least 2 mm smaller than the width W of the blade distally with respect to (and adjacent to) those notches 13a, see Fig. ID. As will be appreciated by the skilled person, the distal blade section that extends distally with respect to the notched blade section lib enters the cylinder during operation, for operating the lock.

In other words: the width W of the notchless blade section that is located distally with respect to (and next to) the notched blade section 1 lb is (significantly, i.e. at least 25%) larger than the width V of the notched blade section lib.

It follows that the width V of the notched blade section 1 lb is preferably at least 35% smaller than the width W of the blade section that is located adjacent to that notched blade section lib (and in particular located proximally with respect to the relief 15, and distally with respect to the notched blade section 1 lb), for example at least 40% smaller.

According to a non-hmiting embodiment, a thickness of the blade 11 (i.e. a lateral distance between the two blade sides 12) can be in the range of 2-3 mm.

Naturally, different blade dimensions can also be implemented.

According to a preferred embodiment, the or each longitudinal groove 14, 18 reaches from a tip of the blade 11c to and through the notched blade section lib. In this way, the longitudinal groove or grooves 14, 18 can provide further local material reduction of the notched blade section 1 lb (thereby enhancing weakening of that section). Figures 2 A, 2B show an example of a cylinder lock 1, including a lock case 2 having a cylinder 3 rotatable relative to the lock case 2, and a number of tumblers 4 for releasably blocking rotation of the cylinder 3. As will be appreciated, the cylinder 3 can be coupled to or cooperate with bolting means BM of the lock, such that the cylinder 3 can retain those bolting means BM in a bolting state when the cylinder 3 is in a first rotational position with respect to the case 2, wherein the cylinder 3 releases the bolting means BM when the cylinder 3 has been turned over a certain angle from the first to a second rotational position.

The lock can be configured to interact with the key 10 shown in Figure 1. The lock 1 can e.g. be a bicycle lock (for example a bicycle ring lock), or a different type of lock, e.g. a padlock, as will be appreciated by the skilled person. In Figures 2A-2D, the key 10 has been inserted in the cylinder 3 of the lock (i.e. in a key receiving space or slot of the cylinder), in particular to move the tumblers 4 to cylinder release positions. In particular, the relief 15 of the longitudinal groove of the key 10 can cooperate with the tumblers 4 of the lock 1 to release the cylinder 3 so that the key can be turned from the depicted first key position to a unlocking state (shown in Fig. 3), turning the cylinder to a lock release position.

For example, the lock can include an external key insertion opening (slot) 9a defined by an integral key guiding part 9 of the lock case 2, in particular by a hardened steel plate (i.e. plate-like element) 9 that is connected to or attached to another part of the lock case 2. The key insertion slot 9a can be located axially in line with a center axis of the cyhnder 3

In particular, the key guiding part 9 can have a rotationally fixed position with respect to the lock case 2 (such that an inserted key 10 is to be turned with respect to the key guiding part 9 for turning the cylinder). It is preferred that the key guiding part 9 is made of hardened steel, to protect the interior of the lock (i.e. the cyhnder 3) against drilling operations. The key insertion slot 9a of the key guiding part 9 can e.g. have a generally rectangular (or elongated) contour/shape, e.g. substantially matching a contour (viewed in cross-section) of a blade 11 of the respective key 10, as well as a central widened section for receiving the notched section 1 lb of the key 10 (when the key is in a fully inserted position in the lock). The key guiding part 9 of the lock case 2 can include or define opposite notch guide rims 9b for guiding the notched section 1 lb of the key blade 11 during key rotation, from an idle state to an unlocking state, with respect to the lock 1. Thus, the opposite notch guide rims 9b can enclose said central widened section of the key insertion slot 9a. In particular, a distance Ql between those opposite notch guiding sections 9b (i.e. a width of a respective central widened section of the key insertion slot 9a) is smaller than a main lateral width Q2 of a key entry slot 9a. It follows that a fully inserted key 10 has its notched section lib located in the key guiding part 9, between the guiding notches 13a thereof. From that position, the key 10 can be turned for turning the cylinder 3, wherein the notched blade section lib can rotate within the key guiding part of the lock 1 (the two notches 13a of the key 10 receiving the guide rims 9b of the guiding part 9), to a second position (shown in Figure 3).

In case a matching key 10 has been inserted in the lock 1 (so that all cylinder tumblers are moved to release positions by the key), the key 10 can be turned using relatively little torque to open the lock. On the other hand, in case a non-matching key (or key-like element) is inserted that does include a blade having the two notches in longitudinal edges, but does not have the proper relief to operate all the tumblers of the cylinder, turning the inserted key (or key -like element)with respect to the lock case 2 will lead to relatively high torque in the blade such that the key (or key-like element) can deform or break between the notches.

Figure 4 shows that a blade of an inserted key NMK that does not have a notched section can not be turned with respect to the key guiding part 9 (since the guide rims 9b block key rotation), in which case the key guiding part 9 prevents key rotation and lock operation directly.

Figures 5 A, 5B depict another example of a key 10’. A difference of this example with the above-described first embodiment is that the key 10’ includes two straight longitudinal grooves 18’, extending along the edges of the key in the second key side (instead of a central longitudinal groove 18), these two grooves 18’ e.g. not including a tumbler operating relief. Besides, the blade of the key 10’ of the second embodiment can have a generally smaller cross-section (mm ² ) than the blade 11 of the first embodiment. For example, regarding the embodiment shown in Figure 5, a transversal cross- section of the notched blade section 1 lb’ can be smaller than 10 mm ² , and for example larger than 7 mm ² , the cross-section e.g. being in the range of 7- 8 mm ² . Also, for example, a transversal cross-section of the adjacent (non- notched) blade section of the second embodiment can be at least about 11 mm ² , for example in the range of 12-13 mm ² .

Regarding the second embodiment, as in the first embodiment, good results can be achieved in case a transversal cross-section of the notched blade section lib’ (i.e. a respective area of that cross-section) is at least 25% smaller (preferably at least 35% smaller, for example at least 40% smaller) than the transversal cross-section (i.e. a respective area of that cross-section) of a blade section that is located adjacent to the notched blade section 1 lb and proximal with respect to the relief 15.

Operation of the second embodiment is the same as that of the first embodiment, wherein the key 10’ also includes a weakened section lib’ in its blade 11’, by notches 13’ between a cylinder operating relief 15’ and a key head section.

Figure 6 depicts a lock 1’ having an external key insertion opening (slot) 9a’ defined by an integral key guiding part 9’ of the lock case 2, in particular by a hardened steel plate 9’. The key guiding part 9’ is depicted in more detail in Figures 7 A, 7B, 7C. Similar to the above-described first example, the key guiding part 9’ of the lock case 2’ can include or define opposite notch guide rims 9b’ for guiding the notches 13a’ of the longitudinal outer edges 13 of the key blade 11’ during key rotation, from an idle state to an unlocking state, with respect to the lock 1. The opposite notch guide rims 9b’ can enclose a central widened section of the key insertion slot 9a’. In the present example, the central widened section is shaped to allow a maximum turning angle of the key 10’ during key operation. For example, the key guiding part 9’ can include blade blocking sections 9c’ arranged to abut (and stop) one or both of the flat sides 12 of the notched blade section 1 lb when the fully inserted key 10’ has been turned to an unlocking state with respect to the lock 1’. Thus, during operation, a maximum key turning angle can be defined by the shape of the central widened section of the key receiving slot. The key guiding part 9’ can interact (via the blocking section 9c’) with the weakened section 1 lb’ of the blade, reducing chances that a user tries turning the key further than required for opening the lock.

The invention is by no means limited to the embodiments specifically disclosed and discussed here above. Many variations thereof are possible, including but not limited to combinations of parts of embodiments shown and described.

For example, any dimension or number mentioned in this apphcation can be the respective dimension or number plus or minus 10% of that dimension or number.

Also, it is preferred that a key guiding part 9 is fixed (i.e. rotationally fixed) with respect to a lock case 2 but that is not required. Alternatively, the lock case can include a key guiding part to provide a key opening that is rotatable, together with the key, during operation.