The present invention relates to a cylinder lock and associated key.

Cylinder locks and associated keys are known the characteristics of which are described in European Patent no. EP 1121502 (priority, Italian application no. BO98A000586 filed on 15 October 1998) in the name of the same Applicant. In this document a cylinder lock is described the code of which cannot be deciphered immediately from the outside, in order to hinder the tampering thereof.

This result is obtained by arranging at least one pin at right angles, with respect to the key way, in the rotor of the cylinder, the pin having a respective end that protrudes into the channel.

The pin is associated with respective complementary pins that can translate elastically between a configuration in which they are fully accommodated in the rotor and at least one configuration of simultaneous accommodation in the stator and in the rotor, with consequent coupling of these two parts.

The pin and the respective complementary pin are arranged on regions that differ from the expansion (generally downward) of the stator (which accommodates the pins and the complementary pins that are intended to mate with the encoding of the key as in any cylinder lock).

In the case described in European Patent no. EP1 121502, the key has a movable tumbler, which is forced elastically into conditions of substantial coplanarity with a respective surface of the key; such tumbler is accommodated slidingly in a respective seat of the key.

When the key is inserted in the keyway, the key actuates the pins, arranging them so that the complementary pins are in the configuration of total accommodation in the stator, allowing an optional movement of the rotor as a result of an action of rotation of the key.

The presence of the movable tumbler in the key, associated with the at least one pin dedicated thereto, ensures a greater security of the lock against effractive actions, which are generically defined as lock-picking (mechanical tampering).

The pin that acts on the movable tumbler is, in fact, constituted by an actual pin provided with an end stem, which engages in a complementary pin provided with a cavity of shape and dimensions that are complementary to those of the stem. Adapted elastic means are arranged between the pin and the complementary pin and are intended to keep them at the maximum mutual distance.

When the lower end of the pin abuts against the movable tumbler, a compression of the elastic element arranged between the movable tumbler and its seat in the key is generated: the elastic action of the elastic element controlled by the tumbler will be stronger than that of the elastic means interposed between the pin and the complementary pin, thus producing a compression of those means.

In practice, a movement of the rotor will be possible only when the respective key is inserted correctly in the keyway of the lock, so as to release the at least one perpendicular pin provided with the above mentioned elastic means.

However, numerous difficulties arise in terms of encryption and encoding of the pins and of the movable tumbler associated with them.

The pins that cooperate with the movable tumbler of the key, which are described and claimed in European Patent no. EP1121502, in fact have predefined and standardized dimensions, as does the tumbler, which has a shape and dimensions that are imposed by those of the pins that can be associated with it.

The aim of the present invention is to solve the problems described above, by proposing a cylinder lock and associated key that have high security against effractive action of the type of lock-picking.

Within the scope of this aim, an object of the invention is to propose a cylinder lock and associated key that allows the dimensional encoding of pins that interact with the movable tumbler of the key.

A further object of the present invention is to provide a cylinder lock and associated key that are low cost, easily and practically implemented and safe in application.

This aim, as well as these and other objects that will become better apparent hereinafter, are achieved by a cylinder lock and associated key, which comprises a fixed stator and a rotor, which is accommodated in a respective cavity of said stator and can rotate with respect to said stator, said rotor comprising a substantially longitudinal compartment for the functional accommodation of a key that comprises a grip from which an elongated body extends which is provided with encoding depressions and protrusions on its outer surface, between said rotor and said stator there being respective accommodation channels for translating encoding elements, said channels being open onto said substantially longitudinal compartment, characterized in that said rotor comprises at least one auxiliary duct, which faces said substantially longitudinal compartment and is extended at least partially in said stator, for the sliding accommodation of at least one encoding unit constituted by at least one contoured dowel and at least one bushing, said dowel being accommodated at least partially in the internal cavity of said bushing, axially acting elastic means being interposable between said dowel and said bushing, the end front of said bushing, which faces said substantially longitudinal compartment, abutting, in the configuration of use, against the head of a movable tumbler, which is accommodated elastically in a recess of said key.

Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the cylinder lock and of the associated key according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a front sectional view, taken along a transverse plane that is perpendicular to the axis of symmetry of the rotor, of a cylinder lock that accommodates an associated key according to the invention in the inactive configuration;

Figure 2 is a front sectional view, taken along a transverse plane that is perpendicular to the axis of symmetry of the rotor, of a cylinder lock that accommodates an associated key according to the invention in a partially open configuration;

Figure 3 shows the lock of Figure 1 , in the view of Figure 1 , without the key in the inactive configuration;

Figure 4 shows the lock of Figure 1 , in the view of Figure 1, without the key during an attempt at effractive tampering;

Figure 5 shows the lock of Figure 1, in the view of Figure 1 , provided with a key with a movable tumbler the height of which is lower than that intended, in the inactive configuration;

Figure 6 shows the lock of Figure 1, in the view of Figure 1, provided with a key with a movable tumbler the height of which is lower than that intended, during an attempt at effractive tampering;

Figure 7 shows the lock of Figure 1, in the view of Figure 1, provided with a key that lacks a movable tumbler, in which there is a hollow instead of the tumbler, in the inactive configuration;

Figure 8 shows the lock of Figure 1, in the view of Figure 1, provided with a key that lacks a movable tumbler, in which there is a hollow instead of the tumbler, during an attempt at effractive tampering;

Figure 9 shows the lock of Figure 1, in the view of Figure 1, provided with a key with a surface that faces an auxiliary duct of the stator and rotor and is flat and continuous, in the inactive configuration;

Figure 10 shows the lock of Figure 1, in the view of Figure 1, provided with a key with a surface that faces an auxiliary duct of the stator and rotor and is flat and continuous, during an attempt at effractive tampering; Figure 1 1 shows the lock of Figure 1, in the view of Figure 1, provided with a key with a movable tumbler the height of which is different from that intended, in the inactive configuration;

Figure 12 shows the lock of Figure 1, in the view of Figure 1, provided with a key with a movable tumbler the height of which is different from that intended, during an attempt at effractive tampering;

Figure 13 is a front sectional view, taken along a transverse plane that is perpendicular to the axis of symmetry of the rotor, of a possible variation of a cylinder lock that accommodates an associated key according to the invention, in the inactive configuration;

Figure 14 is a front sectional view, taken along a transverse plane that is perpendicular to the axis of symmetry of the rotor, of the variation of Figure 13 according to the invention, in a partially open configuration;

Figure 15 is a front sectional view, taken along a transverse plane that is perpendicular to the axis of symmetry of the rotor, of another possible variation of a cylinder lock that accommodates an associated key according to the invention, in the inactive configuration;

Figure 16 is a front sectional view, taken along a transverse plane that is perpendicular to the axis of symmetry of the rotor, of the variation of Figure 15 according to the invention, in a partially open configuration;

Figure 17 is a front sectional view, taken along a transverse plane that is perpendicular to the axis of symmetry of the rotor, of a further possible variation of a cylinder lock that accommodates an associated key according to the invention, in the inactive configuration;

Figure 18 is a front sectional view, taken along a transverse plane that is perpendicular to the axis of symmetry of the rotor, of the variation of Figure 17 according to the invention, in a partially open configuration;

Figure 19 is a front sectional view, taken along a transverse plane that is perpendicular to the axis of symmetry of the rotor, of an additional possible variation of a cylinder lock that accommodates a corresponding key according to the invention, in the inactive configuration;

Figure 20 is a front sectional view, taken along a transverse plane that is perpendicular to the axis of symmetry of the rotor, of the variation of Figure 19 according to the invention, in a partially open configuration;

Figure 21 shows the lock of Figure 19, in the view of Figure 19, provided with a key with a movable tumbler the height of which is greater than that intended, in the inactive configuration;

Figure 22 shows the lock of Figure 19, in the view of Figure 19, provided with a key with a movable tumbler the height of which is greater than that intended, during an attempt at effractive tampering.

With particular reference to these figures, the reference numeral 1 generally designates a cylinder lock and the reference numeral 2 designates the associated key.

The cylinder lock 1 comprises a fixed stator 4 and a rotor 3, which is accommodated in a respective cavity 5 of the stator 4 and can rotate with respect to the stator 4 in such cavity 5, upon an external action (generally performed by the key 2 for opening and/or closing the lock 1).

The rotor 3 comprises a substantially longitudinal compartment 6 for the functional accommodation of the key 2.

In turn, the key 2 comprises a grip from which an elongated body extends which is provided with encoding depressions and protrusions on its outer surface.

Respective accommodation channels are provided between the rotor 3 and the stator 4 for translating encoding elements according to the traditional method of providing cylinder locks: such channels are in fact open onto the substantially longitudinal compartment 6 in order to allow respective pins which are accommodated therein to interact with the encoding depressions and protrusions that are arranged on the outer surface of the key 2.

The pins adopted for interaction with the depressions and protrusions of the key 2 will preferably be constituted by two mutually separate elements (normally known as pin and complementary pin) that are aligned and spring-loaded: the shape of such separate elements will preferably be chosen from among those of the known type which are intended to hinder effractive actions of the type of lock-picking.

According to the invention, the rotor 3 comprises at least one auxiliary duct 7, which faces the substantially longitudinal compartment 6.

The auxiliary duct 7 extends at least partially in the stator 4 as well (defining a specific recess 8 that is described better hereinafter) and is intended to accommodate slidingly at least one encoding unit 9 constituted by at least one contoured dowel 10 and at least one bushing 11.

The dowel 10 is accommodated at least partially in the internal cavity 12 of the bushing 11.

It should be noted that, in order to keep the dowel 10 and the bushing 11 in the configuration of maximum overall length of the encoding unit 9 that they constitute in the inactive configuration, axially acting elastic means 13 can be interposed between the dowel 10 and the bushing 11 : in practice, as in the accompanying figures, these means can be an axially acting helical spring, although the use of different elastic means intended to achieve the same purpose is not excluded.

The end front 11a of the bushing 11, which faces the substantially longitudinal compartment 6, abuts, in the configuration of use, against the head 14 of a movable tumbler 15, which is accommodated elastically in a recess 16 of the key 2.

More specifically, a predefined portion that extends at least partially in the stator 4 of the at least one auxiliary duct 7 (a duct 7 that, as illustrated previously, faces the substantially longitudinal compartment 6) defines a recess 8 that has inclined mutually opposite limiting surfaces and a maximum depth at its portion that is aligned with the auxiliary duct 7, when this is in the inactive configuration and the rotor 3 has not undergone any rotation with respect to the stator 4.

The recess 8 accommodates, in the inactive configuration, the end of the dowel 10.

The contoured dowel 10 comprises, in particular, a main stem 17 of diameter smaller than the diameter of the internal cavity 12 of the bushing 1 1 and an end head 18 of diameter substantially complementary to the diameter of the internal cavity 12 for its snug sliding therein.

In practice, therefore, the dowel 10 predominantly has a narrow diameter, while only its end head 18 has a larger diameter, which is in any case smaller than the diameter of the cavity 12 in order to be able to slide freely therein.

It should be duly pointed out that the main stem 17 comprises a protruding ridge 19, which is arranged proximate to the end that is opposite to the end head 18 of the dowel 10, which has an outside diameter that is substantially complementary to the diameter of the internal cavity 12 (and therefore substantially similar to the diameter of the end head 18) for its snug sliding in the cavity 12.

The bushing 1 1 has a maximum diameter at its end heads and a minimum diameter at its central part which is interposed between said end heads.

The diameter in the vicinity of the channel 2 of the bushing 1 1 is proximate to and smaller than the diameter of the auxiliary duct 7 for the free snug sliding of the bushing 11 in the auxiliary duct 7.

The bushing 11 has, instead, a length that is substantially similar to the length of the rotor portion of the auxiliary duct 7 and comprises the internal cavity 12, which extends from one of its ends to beyond its centerline.

The bushing 11 furthermore comprises, at its edge that is proximate to the opening of its cavity 12, a protruding radial frame 20: the protrusion of the radial frame is even more evident if one takes into account the reduction in diameter of the bushing 11 at its central part (interposed between the two end heads of which the diameter is close to, and smaller than, the diameter of the auxiliary duct 7). It should be noted that one head is the frame 20, which has a larger diameter than that of the auxiliary duct 7.

The auxiliary duct 7, proximate to the shear plane between the rotor 3 and the stator 4, comprises an indentation 21 the shape and dimensions of which are complementary to those of the protruding radial frame 20 for its sliding accommodation.

The bottom of the indentation 21, however, constitutes a stroke limiting shoulder for the frame 20 in order to prevent the bushing 1 1 itself from descending, along the auxiliary duct 7, beyond a predefined height.

With particular reference to the arrangement assumed by the bushing 1 1 in the installation configuration (and therefore in the configuration of use of the lock 1), i.e., when it is inserted in the auxiliary duct 7, the surface directed toward the stator 4 of the protruding radial frame 20 is beveled with a substantially frustum-like shape.

This allows a sliding of such bevel of the protruding radial frame 20 on the mutually opposite and oppositely inclined surfaces of the recess 8 of the stator 4.

It is furthermore specified that, according to a particular constructive solution of unquestionable interest in practice and in application, axially acting elastic means 13 are interposed between the bottom of the cavity 12 of the bushing 11 and the protruding ridge 20 of the dowel 10.

The overall length of the encoding unit 9, i.e., of the dowel 10 and of the bushing 11, when the spike 22 of the dowel 10 abuts against the bottom 23 of the cavity 12, is substantially similar (slight differences in length, compensated by the action of the elastic means controlled by the tumbler 15, are possible) to the distance in a radial direction between the outer surface of the head 14 of the movable tumbler 15 and the internal surface of the stator cavity 5 (i.e., equal to the length of the rotor portion of the auxiliary duct 7 from which the thickness of the key 2 has been subtracted at its region that accommodates the tumbler 15, when the tumbler 15 is compressed against the bottom of the respective accommodation recess 16).

According to a possible constructive solution of unquestionable interest in practice and in application, the end front 11 a of the bushing 1 1 can comprise a protrusion 24 the shape and dimensions of which are complementary to those of a receptacle 25 arranged on the head 14 of the movable tumbler 15; when the lock 1 is in the configuration of free rotation of the rotor 3 with respect to the stator 4, the protrusion 24 is accommodated at least partially in the receptacle 25.

The complementary shape of the protrusion 24 and of the receptacle 25 will allow the accommodation of the former in the latter exclusively if key 2 used to try to open the cylinder lock 1 is the one dedicated to that lock 2: a key 2 that does not have a correctly shaped receptacle 25 will not allow the correct entry of the protrusion 24 therein and will cause the jamming of the encoding unit 9 in the auxiliary duct 7 (in particular, if the receptacle 25 is deeper, the head 18 of the dowel 10 will abut, interfering with them, against the complementarily inclined walls of the recess 8 of the stator 4, thus preventing the rotation of the rotor 3 with respect to the stator 4). If instead the receptacle 25 is less deep, the frame 20 will jam against the complementarily inclined walls of the recess 8 and against the plane 3 a.

With particular reference to the constructive solution described previously, the head 14 of the movable tumbler 15 of the key 2 can optionally have a convex shape: in such case, the receptacle 25 will be arranged substantially proximate to the top of the convexity of the head 14 of the tumbler 15.

As an alternative, it should be noted that the head 14 of the movable tumbler 15 of the key 2 could also be flat: in this version, the receptacle 25 is arranged centrally on the head 14.

A further constructive variation identifies a head 14 of the movable tumbler 15 which has a concave shape: according to this variation, the receptacle 25 is arranged substantially proximate to the bottom of the concavity of the head 14 of the tumbler 15.

If it is desired to analyze the operation of the lock 1 according to the invention, in association with the respective key 2, it becomes necessary to analyze some of the possible steps of possible effractive tampering.

In particular, if an attempt is made to pick the lock 1 without inserting the key 2 in the longitudinal compartment 6 (or rather without inserting any key 2), a hypothesis shown in Figures 3 and 4, it will be found that once the encoding elements that translate in the stator and rotor channels are released in order to uncouple the rotor 3 from the stator 4, the encoding unit 9 will continue to mutually couple them.

In fact, upon an attempt to turn the rotor 3 with respect to the stator 4, the dowel 10 will tend to tilt, arranging itself at an angle with respect to the internal cavity 12 of the bushing 1 1 : the end head 18 of the dowel will then jam against the frame 20 of the bushing 1 1 and in the recess 8 of the stator 4, thus preventing any rotation of the rotor 3 with respect to the stator 4.

In such configuration, the frame 20 will abut against the bottom of the recess 21 that constitutes a shoulder for the radial translations toward the center of the rotor 4 of the bushing 11.

If the burglar has a key that has a tumbler of reduced height that is complementary to the dowel 10 and the bushing 1 1 (a situation shown by way of example in Figure 15), what will happen is that the rotor 3 will jam, because the dowel 10 and the bushing 11 are arranged at the stroke limit with respect to each other (the interposed spring 13 is completely compressed) and the channel 7 is occupied completely by them: the dowel 10 and the bushing 1 1, therefore, will be unable to descend.

A similar situation occurs when the burglar has a solid key the shape of which is similar to the one assumed by the key in Figure 13 or in Figure 15 (i.e., the key of the burglar will have a hollow at the tumbler 15 the shape and dimensions of which are similar to those assumed when the key of Figures 13 and 15 has the tumbler compressed by the dowel 10 and the bushing 1 1).

But if the burglar has a key that has characteristics similar to those of the key 2 that is complementary to the lock 1, but the key of the burglar has a tumbler that is lower than the tumbler 14 of the original key 2, once again an arrangement of the bushing 1 1 will occur by which its frame 20 will rest against the bottom of the hollow 21.

The consequence is that once again the dowel 10 will tend to tilt, arranging itself at an angle with respect to the internal cavity 12 of the bushing 11 and preventing rotations of the rotor 3 with respect to the stator 4.

It is important to note that the lock 1 according to the invention, during an attempt at effractive tampering, can undergo a small rotation (a few degrees) of the rotor 3 with respect to the stator 4: this small rotation causes the locking of the dowel 10 with respect to the bushing 11 in configurations that prevent additional rotations of the rotor 10, thus ensuring that the lock 1 cannot be opened.

A case similar to the two described previously occurs if the burglar tries to use a key that comprises a cutaway (therefore the absence of material) at the auxiliary duct 7 (where the original key 2 comprises the tumbler 15); this solution is shown by way of example in Figures 7 and 8.

Also in this case, the frame 20 of the bushing 1 1 will rest against the bottom of the hollow 21 and the tumbler 10 will tend to tilt, arranging itself at an angle with respect to the internal cavity 12 of the bushing 1 1, thus preventing rotations of the rotor 3 with respect to the stator 4 (except for a possible minimal rotation of a few degrees).

Figures 9 and 10 instead show a condition in which the burglar has a solid key, i.e., a key in which the auxiliary duct 7 faces a continuous flat surface of the key when it is inserted in the longitudinal compartment 6 of the rotor 3.

The frame 20 of the bushing 11, as in the preceding cases, will rest against the bottom of the hollow 21 and the pin 10 will tend to tilt, arranging itself at an angle with respect to the internal cavity 12 of the bushing 11, thus preventing rotations of the rotor 3 with respect to the stator 4 (except for a possible minimal rotation of a few degrees).

A different hypothesis relates instead to the case in which the burglar has a key that is provided with a tumbler but in which the tumbler is lower than that of the original key 2 (a possibility shown schematically in Figures 11 and 12).

If an attempt is made to turn the key (assuming that, as in the preceding cases, the burglar has been able to release the other translating encoding elements), a condition similar to that of the preceding cases will occur in which the dowel 10 will arrange itself at an angle, thus preventing further rotations of the rotor 3 with respect to the stator 4.

A further hypothesis to be considered is the one relating to the use, on the part of the burglar, of a key 2 that is provided with a tumbler 15 but in which the tumbler 15 is higher than that of the original key 2: in this case, the bushing 11 will protrude from the rotor portion of the auxiliary duct 7, and be accommodated partially in the stator recess 8.

If an attempt is made to turn the key 2 (and the rotor 3 with it), what will happen is that the bushing 11 will become misaligned and will tilt, jamming its frame 20 against the outer surface of the rotor 3 that is proximate to the auxiliary duct 7. This transverse arrangement of the bushing 11 (allowed by the reduced-diameter portion arranged between the two end heads) will block the rotor 3, preventing the opening of the lock 1.

According to a particular constructive solution of unquestionable interest in practice and in application, the rotor 3, in the vicinity of the end front of the rotor portion of the auxiliary duct 7, comprises a peripheral flattened region 3a: the presence of this flattened region 3a will facilitate the misalignment of the bushing 1 1, which will tilt, jamming its frame 20 against the flattened region 3a if the tumbler 15 is higher than that of the original key 2.

This last effraction possibility is exemplified in Figures 21 and 22 in relation to a lock 1 that is similar to the one shown in Figure 1 : it should be noted that the versions of the lock 1 shown in Figures 13, 15, 17 and 19 also hinder, in the same manner (i.e., by means of the misalignment of the bushing 11 with consequent locking of the rotor 3, owing to the frame 20 jammed in the recess 8 in such condition), any attempt to force the lock 1 using a key with a movable tumbler that is higher than expected.

The tumbler shown in Figures 21 and 22 in turn can comprise end receptacles 25 that are complementary to the end of the bushing 12. If the burglar has a key that replicates this shape but does not exactly match the original key, what will happen is that the rotation of the rotor 3 will be blocked in a manner similar to that identified by Figure 22.

It has thus been demonstrated that the lock 1 according to the invention can be opened only by using the key 2 that is complementary thereto: the use of keys lacking movable tumblers and/or the use of keys that have movable tumblers of incorrect height (higher or lower than that expected) or are incorrectly shaped will cause the blocking of the lock 1 following a rotation of a few degrees of the rotor 3 with respect to the stator 4, imposed with one of these keys for purposes of effraction.

The present invention is particularly interesting since it makes it possible, by way of a variation of the length of the dowel 10 and of the bushing 1 1 when they are mutually coupled (and therefore optionally also the variation of the depth of the internal cavity 12), to modify the encoding of the encoding unit 9, making it possible to provide a plurality of different variations, each of which can be opened exclusively with a respective key 2 that is dedicated to it.

Furthermore, the fact that when the lock 1 lacks a key 2 inside it, the bushing 1 1 and the dowel 10 are not coupled in a packed configuration (therefore the fact that the spike 22 of the dowel 10 is not resting against the bottom of the cavity 12) makes it harder for any burglar to identify their overall length when they assume this configuration. Only by knowing this overall length would it be potentially possible to reproduce a key with a movable tumbler the height and maximum stroke of which are adapted to allow opening (i.e., to reproduce a key that is identical to the original key 2).

In practice, the lock 1 according to the invention offers the same advantages offered by a spring-loaded pin/complementary pin assembly of the known type (in which, therefore, it is not possible to identify straightforwardly the overall length in order to deduce how to arrange them for release) and at the same time it utilizes the typical advantages of a technical solution in which the dowel 10 and the bushing 11 are in a packed configuration (in the manner described previously), a condition for which, that is to say, any elastic means 13 interposed between them cease to have an important role.

Conveniently, the present invention solves the problems described previously, by proposing a cylinder lock 1 and an associated key 2 that have high security against an effractive action of the type of lock-picking, for the reasons already described.

Advantageously, the cylinder lock 1 and the associated key 2 allow the dimensional encoding of the encoding unit 9 that interacts with the movable tumbler 15 of the key 2 (in particular the dimensional encoding of the dowel 10, the bushing 11 and the depth of the internal cavity 12).

Usefully, the cylinder lock 1 is low cost, easily and practically implemented, and safe in application.

Finally, it should be noted that if the key has a movable tumbler 15 of height lower than the thickness of the key 2 and which therefore defines a concavity with respect to the surface of the key 2, it will not be necessary to provide a slot that is aligned with the tumbler 15 as in the constructive solutions of the known type.

The encoding unit 9 in fact is able to yield (the dowel 10 is accommodated in the cavity 12 inside the bushing 11 with the interposition of a spring 13) and therefore it can partially enter the recess 8, it can therefore reduce its length while the key 2 is being inserted and it can extend again upon the alignment (of the unit 9) with the tumbler 15 (which in turn yields elastically).

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the accompanying claims; all the details may furthermore be replaced with other, technically equivalent elements.

In the examples of embodiment shown, individual characteristics, given in relation to specific examples, may in reality be interchanged with other, different characteristics that exist in other examples of embodiment.

In practice, the materials employed, as well as the dimensions, may be any according to the requirements and the state of the art.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.