The invention relates to a method for making a key of a disc tumbler cylinder lock, as well as to a key blank and a series key for a disc tumbler cylinder lock.

BACKGROUND OF THE INVENTION

A disc tumbler cylinder lock is a widely used lock structure which comprises a fixed outer cylinder, in ^¬ side which there is an inner cylinder. Inside the inner cylinder there are a number of tumbler discs arranged as a pack of discs to be rotated with a key of the lock from their locking positions to opening positions. Each tumbler disc comprises a circumferential notch, a key opening corresponding to the cross-sectional profile of the key so as to form a key passageway, and a circum ^¬ ferential limiter which, in cooperation with a rotation opening of the inner cylinder, is arranged to limit the path of movement of the disc tumbler to a specific cir ^¬ cular sector. In addition, the lock comprises a tumbler bar which in a locked position locks the inner cylinder to the outer cylinder. When the circumferential notches of all tumbler discs are rotated to the position of the tumbler bar, the tumbler bar is arranged to free the inner cylinder to rotate relative to the outer cylinder for opening the lock in a way that the tumbler bar is received in the groove formed by the circumferential notches .

The opening combinations of the disc tumbler cylinder lock amount to millions, but they still are limited. A number of additional combinations have therefore been developed by using keys of a different cross-sectional profile, whereby only a specific key profile fits in the key opening extending through the tumbler discs. The keys of different lock models use a different num ^¬ ber of evenly spaced notches having a standard angle which are made by key cutters manufactured for this purpose. Thus, for example in the ASSA Abloy company's key series Classic®, Exec® and Sento®, only notches corresponding to tumbler disc angles 0°, 18°, 36°, 54°, 72° and 90° are cut on the keys. As to the key series Protec®, the notches to be cut on the keys correspond to tumbler disc angles 0°, 15°, 30°, 45°, 60°, 75° and 90° .

As the variations increase, misopenings in the lock sets increase as well, and locks will open by keys that do not belong to the lock set. For example, residents of an apartment building will have access with their own keys to the apartments of a neighbouring building. The misopenings of lock sets are attempted to be con ^¬ trolled for example with software based on automatic data processing whereby, after the computed variations are complete, it is no more possible to rekey the se- ries in the lock sets. Thus, the only option is to re ^¬ new the lock set as a whole. Renewing a lock set is a very expensive and difficultly predictable operation.

To remedy the problems with current technology, the number of code tumblers should be raised and all ma ^¬ chines and devices on the market for making keys should be replaced with machines and devices that would allow the making of cuts on the keys corresponding to the new tumblers . The invention is also related to a lock assembly device used for making tumbler discs which is disclosed in international patent application PCT/FI2014/050333. The compact lock assembly device enables quick making of tumbler discs regardless of place with accurate and ex ^¬ act notch machining.

OBJECTIVE OF THE INVENTION

The objective of the invention is to remedy the defects of the prior art mentioned above. Specifically, the ob ^¬ jective of the invention is to disclose a novel tech ^¬ nique for extending the size of lock sets and continu ^¬ ing their lifespan in a safe way without increasing the misopening possibilities.

SUMMARY OF THE INVENTION

In the method according to the invention for making a key of a disc tumbler cylinder lock, the key is cut to have lock-model-specific standard angle notches corre ^¬ sponding to tumbler discs of the lock for rotating, when the key is turned in the lock, the tumbler discs of the lock to certain lock-model-specific standard ro ^¬ tation angles. According to the invention, the key is provided with a shape for rotating, when the key is turned in the lock, at least one tumbler disc of the lock to a position that differs from its lock-model- specific standard rotation angles for multiplying the variations of the lock.

The differing shape according to the invention is made in one embodiment of the invention before cutting the lock-model-specific standard angle notches. Thus, the key blank already has the differing shape when it is cut to have the lock-specific notches.

In a second embodiment of the invention, the shape is made at the same time with cutting the lock-model- specific standard angle notches. However, this reguires that the existing cutter machines are modified in ways that such shape that differs from the standard notches can be made .

In a third embodiment, the shape is made after cutting the lock-model-specific standard angle notches. When the above-mentioned inventive shape is made at a dif ^¬ ferent time than the lock-model-specific standard angle notches, they can be made with other cutters or corre ^¬ sponding machines so as to avoid modifications of the standard cutter machines.

Depending on the embodiment, the shape according to the invention can be made by cutting a notch on the shank of the key or by shaping the shank of the key or by adding the shape to the shank of the key. The essential feature is that the shape forms a notch having an angle that differs from the lock-model-specific standard an- gle notches, i.e. the shape rotates one or more tumbler discs to an angle to which they cannot be rotated by any of the standard angle notches.

The invention further relates to a key blank comprising a bow and a shank. According to the invention, the shank comprises a shape arranged to rotate at least one tumbler disc of a disc tumbler cylinder lock corresponding to the key blank to a position that differs from lock-model-specific standard rotation angles. The shape according to the invention may be in a series lock set area, i.e. in the area for cutting a series lock set notch. The shape may also be immediately after an area of a raising zero at the tip of the shank of the key blank.

The shape according to the invention preferably has an angle approximately halfway between standard cutter an ^¬ gles. Depending on the lock sets, the standard cutter angles are for example the angles 0°, 18°, 36°, 54°, 72° and 90° or the angles 0°, 15°, 30°, 45°, 60°, 75° and 90°. It is not obligatory that the angle of the notch with the inventive shape is halfway between standard angles, but it is sufficient that this shape differs to a notable degree from the standard angles, i.e. that malfunctions in the lock are not able to oc ^¬ cur. In general, in precision-made disc tumbler cylin ^¬ der locks it is sufficient to have even a difference of one degree from the standard angles to differentiate between operations of the locks.

The invention further relates to a series key compris ^¬ ing a bow and a shank as well as lock-model-specific standard cutter angle notches cut on the shank and cor- responding to tumbler discs of a lock that corresponds to the profile of the shank. According to the inven ^¬ tion, the series key comprises a shape that differs from said notches, arranged to rotate at least one tum ^¬ bler disc of the lock to a position that differs from the lock-model-specific standard rotation angles. The inventive shape mentioned above may be a notch or a pro ection .

Preferably, the shape has an angle which is approxi- mately halfway between standard cutter angles. The lock-model-specific standard cutter angles may be for example the angles 0°, 18°, 36°, 54°, 72° and 90° or the angles 0°, 15°, 30°, 45°, 60°, 75° and 90°. ADVANTAGES PROVIDED BY THE INVENTION

The method, key blank and series key according to the invention have notable advantages over the prior art. The size of lock sets can be extended and their lifespan continued in a safe way by means of the inven- tion without increasing misopenings. When the combina ^¬ tions of a specific lock set have been used up, it is possible to bring into use a completely new lock set, i.e. a new lock set in the old lock set, by using a single shape that differs from the standard angles in the keys. This is done in the simplest way by making such differing notch already in the key blanks. Then, the normal standard angle notches can be made with the existing standard cutter machines on the blank provided with such a notch so that they do not fit in any exist- ing locks already in use. A new lock cylinder with new tumbler discs is then made by filling uncut tumbler discs in the inner cylinder of the lock, by rotating, with the new key, the tumbler discs to the opening po ^¬ sition determined by the key, and by cutting the rotat- ed tumbler discs to have a notch for a tumbler bar as described in more detail in the above-mentioned inter ^¬ national patent application PCT/FI2014/050333.

Even a single new notch or other shape that differs from the standard angles doubles the number of differ ^¬ ent combinations for use in the lock set. When the an ^¬ gle of this notch in changed and it is maintained dif ^¬ ferent from the standard angles, yet another new combi ^¬ nation series is obtained. For example, with factory- made key blanks it is thus possible, by changing the angle of a single notch, to multiply the number of dif ^¬ ferent locking combinations of the same lock series in a safe and secure way. The safety of widely used and old lock series is even increased by the invention, be ^¬ cause the keys are provided with notch angles which, with the normal key cutters as such, are not even pos ^¬ sible to be made. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail with ref ^¬ erence to the accompanying drawings, in which

Fig. 1 illustrates a conventional key blank,

Fig. 2 illustrates the key blank according to the in- vention and

Fig. 3 illustrates the key according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 illustrates a conventional key blank which com- prises a bow 1 and a shank 2. Such uncut key blanks with a smooth shank are used by locksmithing stores when they make keys for locks with their cutter machines . Fig. 2 illustrates the key blank according to the invention, which also comprises a plate-shaped bow 1 and a cross-sectionally semicircular shank 2. However, the shank 2 is already beforehand in factory conditions or otherwise before making the actual tumbler notches ma- chined to have a shape 3, i.e. a notch in this embodi ^¬ ment. The angle 4 of the notch, shown at the tip of the key blank in a dotted line, differs from all angles which are used in a lock model corresponding to this key as tumbler notches. In Fig. 3, tumbler notches have been made on the key blank of Fig. 2, i.e. the key is ready. The angles of the tumbler notches vary along the shank as follows: the angle of a first notch 5 is 54°,

the angle of a second notch 6 is 0°,

the angle of a third notch 7 is 18°,

the angle of a fourth notch 8 is 36°,

the angle of a fifth notch 9 is 90°,

the angle of a sixth notch 10 is 36°,

the angle of a seventh notch 11 is 18°,

the angle of an eighth notch 12 is 0°,

the angle of a ninth notch 13 is 54°,

the angle of a tenth notch 14 is 0°.

The last one before an area 15 of a raising zero is the new and inventive shape 3 already provided on the blank as shown in Fig. 2, i.e. a notch with an angle of approximately 82° in this embodiment. Thus, the angle of this notch 3 is such that it does not appear in any standard tumbler notches of this lock model, which are 0°, 18°, 36°, 54°, 72° and 90°. 82° is just about in the middle of the last two angles, i.e. 72° and 90°.

Thus, by making a key having a tumbler notch with a differing angle which rotates a corresponding tumbler disc of the lock in a differing way, a completely new lock series for use in an existing lock set is obtained. It is completely safe to bring all key combina ^¬ tions used previously in this lock set into use again, because the keys are made new and unique due to the new notch 3 that differs from the other notches. In this embodiment, this new and inventive notch 3 is made im ^¬ mediately after the area 15 of the raising zero before the actual tumbler notch area of the key. However, there is no objection to making this new and differing notch in the actual tumbler notch area, i.e. as one of these ten tumbler notches.

Because the angle of the notch 3 differs from the con- ventional angles, it cannot be made with the existing key cutter machines. It is therefore made already be ^¬ forehand on the key blank according to the invention. Locksmiths are thus provided with key blanks having one notch with a differing angle for making the keys. When the tumbler notches of the key are cut, the tumbler discs of the lock can be made with the device and meth ^¬ od according to the above-mentioned international pa ^¬ tent application PCT/FI2014/050333. The locksmith will therefore only need basic tumbler discs free of the notches for a tumbler bar and key blanks according to the invention provided with the differing notch 3, and thereby new lock series can be created and even large lock sets safely rekeyed without the risk that the keys would fit in inappropriate locks.

The invention has been described above by way of exam ^¬ ple with reference to the accompanying drawings, dif ^¬ ferent embodiments of the invention being possible within the scope defined by the claims.