The present invention relates to a forced entry-resistant lock.

Many locks are commercially available which, thanks to specific coding methods and to particular constructive configurations, prevent forced entry actions of various kinds and are thus particularly secure.

The use of a technique known as "impression technique" (or also “impressioned key” or “impression with wax” and other materials that wear easily) by many burglars has been spreading in recent times. This allows to crack even very secure locks and is silent (therefore it does not draw the attention of people who might report the forced entry attempt).

This is a technique by which, by means of resins, wax and/or materials that wear easily, it is possible to make an illegal cast of a copy of the key (active or direct impression).

The burglar requires a probe element (constituted by a blank key with minimized coding onto which a layer of material that is easily deformable or easily removable by abrasion is deposited). By means of such an element it is possible to take an impression of the cavity intended for the key, and of the coding (depending on the position to which the pins must be brought to ensure opening). The impression of the key remains imprinted on the probe element as a result of its insertion and its continuous and alternating movement in clockwise and counterclockwise rotation: this movement causes the head of the pins that abuts against the layer of material deposited on the probe element to deform or abrade said layer until the thickness corresponding to the correct coding is reached at each pin. At this point cloning has taken place: the intruder has detected the shape of the key and can thus open the lock. Moreover, with the probe element thus shaped, it is easy to reproduce an all-metal key with similar geometries (allowing to crack that lock when desired at later times).

Moreover, fully mechanical probe elements have recently been made commercially available which do not require the deposition of the additional layer of material, since they include elastic portions whose elastic constant and protrusion from the key surface can be varied until the lock opens. The principle, however, remains the same: through continuous alternating rotary movements applied to the probe element, the head of the pins of the lock acts on the elastic portions until their correct protrusion from the surface of the element is caused, which will allow to open the lock.

The aim of the present invention is to solve the problems described above by providing a forced entry-resistant lock that is protected against forced entry actions performed with the impression technique.

Within this aim, an object of the invention is to provide a forced entry-resistant lock that is also protected against forced entry actions based on the impression technique and performed with fully mechanical probe elements that do not require the deposition of the layer of additional material.

Another object of the invention is to provide a forced entry-resistant lock that differs as little as possible from those currently commercially available from the standpoint of construction and of the geometry of its components.

Another object of the invention is to provide a forced entry-resistant lock that ensures a good level of protection also against different forced entry approaches.

A further object of the present invention is to provide a forced entryresistant lock that has low costs, is relatively simple to provide in practice and is of assured application.

This aim and these objects, as well as others which will become better apparent hereinafter, are achieved by a forced entry-resistant lock of the type comprising a stator within which a rotor is rotatable, said rotor being provided with a longitudinal channel along which respective coding pins and driver pins face each other and can slide within ducts of said rotor and said stator which are perpendicular to the axis of rotation of said rotor, said channel being adapted for the insertion of a key shaped according to a predetermined code, characterized in that at least one of said coding pins has an axially symmetrical shape and comprises, at its end that abuts against the front of the respective driver pin in the assembled configuration, a substantially disk-like head having a larger diameter than the portion of the coding pin proximate thereto.

Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the forced entry-resistant lock, illustrated by way of nonlimiting example in the accompanying drawings, wherein:

Figure 1 is a schematic sectional front view, taken along a transverse plane, of a lock according to the prior art;

Figure 2 is a schematic sectional side view, taken along a transverse longitudinal plane, of a forced entry-resistant lock according to the invention;

Figure 3 is a sectional view, taken along the plane III-III of Figure 2, of the forced entry-resistant lock of Figure 2;

Figure 4 is a schematic sectional side view, taken along a longitudinal plane, of a forced entry-resistant lock according to the invention in which a key is inserted into the respective keyway;

Figure 5 is a sectional view, taken along the plane V-V of Figure 4, of the forced entry-resistant lock of Figure 4;

Figure 6 is a sectional view that is the opposite of the one of Figure 5;

Figure 7 is a sectional view of Figure 5, in which a counterclockwise rotation of the key by a few degrees has been performed;

Figure 8 is the sectional view of Figure 5, in which a clockwise rotation of the key by a few degrees has been performed;

Figure 9 is a sectional view that it the opposite section of the one of Figure 7;

Figure 10 is a sectional view of a further embodiment of a forced entry-resistant lock according to the invention, in which a counterclockwise rotation of the key by a few degrees has been performed;

Figure 11 is a sectional view of a further embodiment of a forced entry-resistant lock according to the invention, in which a counterclockwise rotation of the key by a few degrees has been performed;

Figure 12 is a sectional view of a further embodiment of a forced entry-resistant lock according to the invention in which a counterclockwise rotation of the key by a few degrees has been performed;

Figure 13 is a sectional view of a further embodiment of a forced entry-resistant lock according to the invention in which a counterclockwise rotation of the key by a few degrees has been performed;

Figure 14 is an enlarged-scale view of a detail of the lock of Figure 9.

With reference to the figures, the reference numeral 1 generally designates a forced entry-resistant lock and the reference letter A designates a traditional lock according to the prior art.

The lock A comprises a stator B within which a rotor C is rotatable which is provided with a longitudinal channel D along which respective coding pins E and driver pins F face each other and can slide within ducts G that pass through the rotor C and the stator B. Such ducts G are perpendicular to the axis of rotation of the rotor C. The channel D is configured to be able to accommodate a key which is shaped according to a predefined code and by means of which it is possible to rotate the rotor C with respect to the stator B, since the key is adapted to align the end fronts of each coding pin E and each driver pin F with the interface surface between the stator B and the rotor C (thus eliminating the constraints on the mutual rotation of the rotor C and the stator B).

A traditional lock A is vulnerable to forced entry attempts performed with the so-called "impression method" (or "impressioned key" or "wax impression"): in fact, by inserting in the channel D a key X in which all the thicknesses at the codes are minimized and in which respective layers made of deformable material (e.g., an elastomer and the like) or of a material that wears easily (e.g., wax, plasticine and the like) have been deposited, it is possible to proceed with a repetition of small alternating rotations that result in the deformation/wear of the layer by the tip of each coding pin E. After a certain number of alternating cycles of small rotations of the rotor C with respect to the stator B, the key X perfectly replicates the original key and it is thus possible to rotate the rotor C with respect to the stator B, opening the lock A.

To obviate such severe drawbacks, the new forced entry-resistant lock 1 according to the invention comprises a stator 2 within which a rotor 3 can rotate which is provided with a longitudinal channel 4 along which respective coding pins 5 and driver pins 6 face each other and are able to slide within ducts 7 of the rotor 3 and of the stator 2 which are perpendicular to the axis of rotation of the rotor 3.

In the assembly configuration, the driver pins 6 do not directly face the channel 4 since they abut, with their end directed toward the channel 4, against a corresponding end of a respective coding pin 5 (also accommodated within the same duct 7).

It is specified that the channel 4 is configured to allow the insertion of a key 8 that is shaped according to a predefined code.

According to the invention, at least one of the coding pins 5 has an axially symmetrical shape and advantageously comprises, at its end that abuts against the front of the respective driver pin 6 in the assembly configuration, a substantially disk-like head 9 having a larger diameter than the portion 10 of the coding pin 5 that is proximate thereto.

The part of the head 9 that is contiguous to the portion 10 comprises a frustum-shaped ring 9a: the frustum-shaped ring 9a has a very important function in aiding the proper operation of the lock according to the invention, since it reduces (to the point of eliminating it) the effectiveness of forced entry actions based on the "impression" technique (also known as "impressioned key" or "wax impression" technique). The function of the inclined ring 9a will be described hereinafter.

With particular reference to an embodiment of unquestionable interest in application, illustrated by way of non-limiting example in the accompanying Figures 3, 5, 6, 7, 8 and 9, it is specified that the at least one coding pin 5 provided with the disk-like head 9 can advantageously comprise a first part 11 that is substantially frustum-shaped and has the minimum diameter at its portion 10 that is proximate to the head 9 and a second tapered part 12 formed between the end region, having the maximum diameter, of the first part 11 and the front of the coding pin 5, which is designed to abut against the surface of the key 8 when it is inserted in the channel 4.

According to an alternative embodiment, illustrated by way of nonlimiting example in the accompanying Figures 10 and 11, the at least one coding pin 5 provided with the disk-like head 9 may advantageously comprise a substantially cylindrical first segment 13 formed between the portion 10 of the coding pin 5 that is associated with the head 9 and an at least partially frustum- shaped front element 14 having a maximum outside diameter that is at least proximate to the diameter of the head 10 and is tapered at its end directed toward the channel 4, in the assembly configuration.

In accordance with a further embodiment, illustrated by way of nonlimiting example in the accompanying Figures 12 and 13, at least one coding pin 5 provided with the disk-like head 9 positively comprises at least one groove 15 at its portion 10 that is proximate to the head 9 and at least one annular shoulder 16 having a diameter that is proximate to the diameter of the head 9. Upstream of the at least one annular shoulder 16 there is usefully a substantially cylindrical region 17 that has a smaller diameter than the shoulder 16 and has an end bulb 18 that has a larger diameter and in which the end that is directed toward the channel 4 is tapered. For the purpose of identifying the geometric and dimensional aspects that ensure that the coding pin 5 according to the invention constitutes an effective protection against forced entry, it is specified that the maximum diameter of the at least one coding pin 5 is favorably smaller than and proximate to the diameter of the duct 7 within which it can slide. The maximum diameter of the coding pin 5 is the one which, in the various configurations examined so far, can be found in the head 9, in the second tapered part 12, in the front element 14, in the shoulders 16 and in the end bulb 18.

It is noted that the diameter of the portion 10 of the coding pin 5 according to the invention (the portion 10 proximate to the disk-like head 9) is conveniently smaller than the maximum diameter by at least 10%: this reduction in diameter ensures engagement of the undercut formed by the assembly of the head 9 and of the portion 10 on the edge of the part of the rotor 3 of the channel 4 when the rotor 3 is partially rotated with respect to the stator 2. Hereinafter, the operation and method by which the lock 1 according to the invention hinders any forced entry attempts performed with the impression (or "impressioned key" or wax impression) technique will be described in greater detail.

In order to maximize security against forced entry actions, it is specified that the lock 1 according to the invention may comprise at least two coding pins 5 (potentially even all of the coding pins 5 that are present may be shaped according to the teachings of the present invention) provided with a respective disk-like head 9, so that at each of them it is possible to block rotation (the edge of the part of the duct 7 that is located in the rotor 3 engages the portion 10 of the coding pin 5, preventing the partial rotations that allow to impress the proper code on a key 100 intended for forced entry).

It is specified that the driver pin 6 also can efficiently comprise at least one end sleeve 19 the dimensions of which are larger than the diameter of the part 20 of the driver pin 6 that is proximate to it.

This shape makes it possible to hinder additional forms of forced entry, such as for example (but not exclusively) lockpicking carried out by means of tools of the type of picks and the like.

Moreover, it is appropriate to specify that the lock 1 according to the invention can validly comprise at least one axially acting spring 21 on the bottom of at least one of the ducts 7 which abuts against one end of a respective driver pin 6 to push said driver pin 6, and the coding pin 5 aligned therewith, toward the channel 4.

Finally, it is noted that the coding pins 5 may favorably have a different length: the length increments/decrements that can be observed between one coding pin 5 and another have discrete and predefined extents. By using coding pins 5 of different lengths it is possible to obtain the desired coding of the lock 1 , which will match that of the key 8 associated therewith.

It is not excluded to obtain this coding also by modifying the shape of the end front of each coding pin 5 (the front facing the channel 4): the key 8 in this case will need to have, at each coding pin 5, a cavity the shape and dimensions of which are complementary to those of the respective shaped end front.

The operation of the invention is as follows.

In the case of normal operation, the insertion of the key 8 in the channel 4 produces the correct alignment of the interface surface between the coding pins 5 and the driver pins 6 at the interface surface between the stator 2 and the rotor 3, and therefore it is possible, by applying a moment, to turn the key 8 and the rotor 3 until the lock 1 is opened.

Should an attacker attempt to open the lock 1 by using a key 100 with reduced thickness and coated with a material that is easily deformed or easily subject to abrasion, by applying the impression technique (also known as the "impressioned key" or wax impression technique) the lock 1 will be found to be unopenable.

In fact, in the course of the movement of the rotor 3 (alternating rotary motion with a stroke of minimum extent, which is used to impress the correct shape on the key 100 by means of the head of the coding pins 5), the coding pin 5 according to the invention locks against the edge of the part of the duct 7 that is present in rotor 3 (as shown in Figures 9 to 13). Such locking prevents the impression of the correct shape to the key 100 (the necessary abrasion/deformation of said key does not occur) and the free rotation of the rotor 3 with respect to stator 2, thus thwarting the forced entry action.

If the frustum-shaped ring 9a is present (on the part of the head 9 that is contiguous to the portion 10), it is specified that when the edge of the part of the duct 7 that is present in the rotor 3 abuts against it (while the forced entry attempt based on the impression or "impressioned key" or wax impression technique is in progress) an axial thrust is generated on the coding pin which will tend to make it partially retract into the stator part of the duct 7 (thus moving it away from the key 100 provided with the means for undergoing coding by the coding pins 5 of the lock 1 itself). The thrust applied by the edge of the part of the duct 7 of the rotor 3 on the frustumshaped ring 9a can in fact be interpreted as the application of a force on an inclined plane: this force is therefore divisible into its components, one of which is applied to the frustum-shaped ring 9a along the direction of the axis of the coding pin 5 that comprises it and is oriented toward the respective driver pin 6.

This result is also achieved with respect to forced entry tools designed for the purpose of opening locks by using the impression technique (also known as "impressioned key" or wax impression technique), such as the device known as "Topolino" or "Topolino decoder."

Advantageously, the present invention solves the problems described earlier by providing a forced entry-resistant lock 1 protected against forced entry actions performed with the impression technique.

Conveniently, the lock 1 according to the invention is also protected against forced entry actions based on the impression technique and performed with fully mechanical probe elements that do not require the deposition of the layer made of additional material (such as the device known as "Topolino" or "Topolino decoder").

The lock 1 according to the invention advantageously differs as little as possible from the standpoint of construction and of the geometry of its components from those currently commercially available.

Advantageously, the lock 1 according to the invention ensures a good level of protection against different forced entry approaches as well.

Validly, the lock 1 according to the invention is found to be relatively simple to provide in practice and of low cost: these characteristics make the lock 1 according to the invention an innovation of assured application.

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 exemplary embodiments shown, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments.

In practice, the materials used, 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.