BREAK-IN RESISTANT CYLINDER FOR LOCKS

Technical Field

The present invention relates to a break-in resistant cylinder for locks, particularly suitable to thwart break-in actions which comprise impulsive percussions on at least one portion of the cylinder.

Background Art

Locks currently exist which comprise a cylinder (in which the opening key is to be inserted) provided with a stator and a rotor which are mutually coupled by means of a plurality of coding pins and tumbler pins which can slide within stator and rotor channels: each stator channel faces, and is aligned with, the respective rotor channel when the cylinder is in the closed configuration (the key is not inserted or is inserted but not rotated with respect to the insertion configuration).

An axially-acting elastic element is provided between the bottom of the stator channel and the lower surface of the tumbler pin and is designed to keep the tumbler pin spaced from said bottom, barring external actions which entail the lowering of the tumbler pin (for example the insertion of the key in the cylinder).

The key, by way of its contoured (coded) profile, acts on the upper surface of the coding pins, lowering them and placing the shear line which separates the bottom of the coding pin from the apex of the tumbler pin in perfect alignment with the shear line that is present between the rotor and the stator, which are substantially mutually disengaged (when the key is inserted). The rotor (when the key is inserted, therefore with the coding pins lowered according to the coding) can be turned by turning the head of the key, which protrudes from the cylinder: in this manner it is possible to open the lock.

Highly effective break-in techniques have been devised recently which are based on the possibility of the effractor to acquire uncoded keys

of the same type as the one associated with a given cylinder.

A key of this type has to be shaped by providing a succession of grooves whose depth is equal to, or greater than, the maximum depth that is present in the original key (associated with the cylinder of interest) and possibly by removing a small part of material from the portion of the key that abuts against the front of the cylinder.

Once this "generic" key has been provided, the break-in action consists in inserting the key in the cylinder, subjecting it to torque and rhythmically striking its protruding head with a means of substantial mass. The percussion of the mass on the head of the key entails a small and very fast advancement of the key in the cylinder, with a consequent impulsive impact of the inclined surface of each of the grooves against the head of the respective coding pin of the cylinder: as a consequence of this impact, the coding pin transfers the accumulated energy to the tumbler pin (since they rest against each other), which is propelled toward the bottom of the stator channel, compressing the spring or other elastic means.

If, following a certain number of successive percussions, all the tumbler pins are at the same time each completely within the respective stator channel, at that instant the rotor and the stator are mutually disengaged (the rotor can rotate freely): the torque applied to the head of key at that moment entails a rotation of the rotor and therefore the opening of the lock.

The described break-in action is substantially applicable to all types of cylinder and is therefore extremely dangerous also in view of the fact that often it does not even leave marks which might indicate that tampering has occurred.

Disclosure of the Invention

The aim of the present invention is to obviate the above cited drawbacks and meet the mentioned requirements, by providing a break-in resistant cylinder for locks which cannot be opened with the described

break-in method.

Within this aim, an object of the present invention is to provide a break-in resistant cylinder for locks which is simple, relatively easy to provide in practice, safe in use, effective in operation, and has a relatively low cost.

This aim and this and other objects which will become better apparent hereinafter are achieved by the present break-in resistant cylinder for locks, of the type which comprises a stator provided with a substantially cylindrical longitudinal cavity for accommodating a rotor with a longitudinal recess for the insertion of a key, said rotor and said stator comprising a plurality of channels which are substantially aligned and face each other when the cylinder is in the closed configuration, channels for accommodating respective coding pins, tumbler pins and any elastic means designed to prevent the rotation of the rotor within the stator if the key is not present in said longitudinal recess, characterized in that at least one of said elements accommodated within a respective channel, i.e., the coding pin and the tumbler pin, is constituted by at least two sleeves, which have a closed end and an open end for access to an internal seat, the open ends of said two sleeves facing each other and resting against each other by way of the action of at least one elastic element which is accommodated within said seats and is rigidly coupled to the bottom of said seats. Brief Description of the Drawings

Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment of a break-in resistant cylinder for locks, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a sectional front view, taken along a transverse vertical plane, of a first embodiment of a cylinder according to the invention in the inactive configuration; Figure 2 is a sectional front view, taken along a transverse vertical

plane, of a first embodiment of a cylinder according to the invention, with the key, modified for break-in purposes, inserted therein;

Figure 3 is a sectional front view, taken along a transverse vertical plane, of a first embodiment of a cylinder according to the invention with the key, modified for break-in purposes, inserted therein and the secondary element in the lowered configuration as a consequence of the percussions applied to the key;

Figure 4 is a sectional side view, taken along a longitudinal vertical plane, of a first embodiment of a cylinder according to the invention with the key, modified for break- in purposes, inserted therein, and the secondary element in the lowered configuration as a consequence of the percussions applied to the key;

Figure 5 is a sectional side view of the coding pin of a first embodiment of a cylinder according to the invention; Figure 6 is an exploded sectional side view of the coding pin of a first embodiment of a cylinder according to the invention;

Figure 7 is a sectional front view, taken along a transverse vertical plane, of a second embodiment of a cylinder according to the invention in the inactive configuration; Figure 8 is a sectional front view, taken along a transverse vertical plane, of a second embodiment of a cylinder according to the invention, with the key, modified for break-in purposes, inserted therein;

Figure 9 is a sectional front view, taken along a transverse vertical plane, of a second embodiment of a cylinder according to the invention with the key, modified for break-in purposes, inserted therein, and the secondary element in the lowered configuration as a consequence of the percussions applied to the key;

Figure 10 is a sectional side view, taken along a longitudinal vertical plane, of a second embodiment of a cylinder according to the invention with the key, modified for break-in purposes, inserted therein, and the secondary

pad in the lowered configuration as a consequence of the percussions applied to the key;

Figure 11 is a sectional side view of the tumbler pin of a second embodiment of a cylinder according to the invention; Figure 12 is an exploded sectional side view of the tumbler pin of a second embodiment of a cylinder according to the invention. Ways of carrying out the Invention

With reference to the figures, the reference numeral 1 generally designates a break-in resistant cylinder for locks. The cylinder 1 comprises a stator 2, which is provided with a substantially cylindrical longitudinal cavity 3 for accommodating a rotor 4. The rotor 4 has a longitudinal recess 5 through which it is possible to insert a key 6.

The rotor 4 and the stator 2 comprise a plurality of channels 7, which are substantially mutually aligned and face each other (when the cylinder 1 is in the closure configuration) and are designed to accommodate respective coding pins 8, tumbler pins 9 and any elastic means 7a. The coding pins 8, the tumbler pins 9 and the elastic means 7a perform the function of preventing the rotation of the rotor 4 within the stator 2 if the key 6 is not present within the longitudinal recess 5.

At least one of the elements accommodated within a respective channel 7, i.e., either the coding pin 8 or the tumbler pin 9, is constituted by two sleeves 10 and 11, which have a closed end (respectively 10a and Ha) and an open end (respectively 10b and l ib) for accessing a respective internal seat (12 and 13 respectively).

The two sleeves 10 and 11 have the open ends 10b and l ib which face each other and rest against each other. Mutual contact is ensured by forcing obtained by inserting within the seats 12 and 13 an elastic element 14 which is rigidly coupled to the bottom 12a and 13a of the seats 12 and 13.

According to the embodiment described in Figures 1 to 6, the element constituted by the two sleeves 10 and 11 is the coding pin 8; according to the embodiment described in Figures 7 to 12, the element constituted by the two sleeves 10 and 11 is the tumbler pin 9. In particular, from a constructive and production standpoint, the elastic element 14 is an axially-acting spring, whose length at rest is substantially shorter than the distance between the bottoms 12a and 13a of the seats 12 and 13, in order to keep the sleeves 10 and 11 in constant mutual contact: in particular, by providing a helical spring with tightly packed turns of the mentioned length, it can be verified that each mutual spacing of the sleeves 10 and 11 is matched by an opposite reaction of the spring which is intended to move them closer together again.

According to another embodiment (not described in the figures but easy to deduce), it is possible to provide a cylinder 1 in which both the coding pin 8 and the tumbler pin 9 are constituted by at least two sleeves 10 and 11 , doubling the uncoupling effect and further increasing the difficulty of any break-in (in particular making it impossible to perform a break-in of the impulsive type).

The tumbler pin 9 is constituted by a substantially cylindrical body, which is provided with two end heads whose diameter is substantially larger than the diameter of the body. This particular shape facilitates the inclination of the axis of the tumbler pin 9 and the subsequent locking thereof between the stator 2 and the rotor 4 in case of break-in attempts using an impulsive method. The surfaces of the open ends 10b and l ib are substantially inclined with respect to the plane which is perpendicular to the axis of the sleeve (10 and/or 1 1) and are mutually complementary in the case of two facing sleeves 10 and 11 : the impulsive break- in action is axial (with respect to the coding pin 8 and the tumbler pin 9), the presence of these inclined surfaces ensures that part of this action is broken down according to a component

which is perpendicular to the axis and facilitates the locking of at least one of the two sleeves 10 and 11 along the shear line between the stator 2 and the rotor 4.

In the case of an impulsive break- in action, the sleeves 10 and 11 associated by means of the elastic element 14 are in fact arranged in an axially offset configuration, tending to be interposed between the stator 2 and the rotor 4.

It has thus been shown that the invention achieves the intended aim and object. The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may further be replaced with other technically equivalent ones. 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 particular, it is possible to provide any number of compartments 10 at will, each of which is matched by a respective unit 11 , said compartments being distributed along the portion of the channel 7 of the stator 2, according to production requirements.

Moreover, it is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer. In practice, the materials used, as well as the shapes and dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims.

The disclosures in Italian Patent Application No. BO2006A000044 from which this application claims priority are incorporated herein by reference.