The present invention relates to a break-in resistant lock, particularly of the type which can be operated by means of double-web keys.
Locks associated with double-web keys are constituted by a main box-like body which is provided with a (substantially transverse) seat which is suitable for the insertion of the key.
The key, once inserted, is arranged so that its coded portion is aligned with a plurality of code plates (usually known as tumblers) which can perform a partial translational motion in preset directions.
The rotation of the key in the seat entails a movement of the plates (tumblers) which is matched by the disengagement of a rod (normally engaged by interference on the plates): such rod can thus be made to perform a translational motion by the rotary motion of the key in the seat.
The bolts are stably coupled on the front portion of the rod: the translational motion of the rod entails the protrusion of the bolts from the front edge of the lock, with a consequent stable engagement thereof in the receptacles of the iamb. ensuring correct closure of the door in which the lock is installed.
A lock according the preamble of claim 1 is disclosed by
This type of lock ensures a good level of protection against destructive break-in actions, since the generous dimensions allow embodiments of the armored type.
However, this type is subject to break-in actions of the type normally known as lock picking.
These techniques adopt specific tools to be inserted in the seat which is adapted to accommodate the key: by means of these tools, by keeping the rod under tension in the direction that corresponds to the retraction of the bolts, the effractor can "lift" the plates individually until the rod is released and said rod retracts as a consequence of the applied mechanical tension.
Although these break-in techniques are rather complex, they have a distinctly high success rate and therefore make all double-web key locks substantially unsafe.
The aim of the present invention is to provide a break-in resistant lock which is provided with means adapted to contrast any break-in action which falls within the field of lock picking.
Within this aim, an object of the present invention is to provide a break-in resistant lock for double-web keys of the type which can be recoded, provided with means adapted to contrast any break-in action which falls within the field of lock picking.
Another object of the present invention is to provide a break-in resistant lock which has low costs, is relatively simple to provide in practice and is safe in application.
This aim and these and other objects, which will become better apparent hereinafter, are achieved by the present break-in resistant lock, of the type that comprises a box-like body for accommodating a plurality of contoured plates provided with a respective portion which is suitable for detachable engagement on a corresponding area of a rod which can perform a translational motion and supports, at its free end, at least one bolt which can retract jointly with said rod, said plates being able to perform a vertical translational motion by way of the action of the key and releasing the translational motion, when they are lifted, of said rod and of said bolts for their retraction and protrusion, at least one of said plates being constituted by a respective rear plate and by a respective front tumbler, which are mutually coupled by means of a complementary contoured portion provided on their mutually facing edges, characterized in that said front tumbler comprises a protruding arm which is interposed between the front of the rear plate and a protective housing, said arm having a shape and dimensions which are complementary to the interspace provided between said plate and said housing to prevent the possibility to access the plate with break-in tools.
Further characteristics and advantages of the invention will become better apparent and evident from the following detailed description of a preferred but not exclusive embodiment of a break-in resistant lock, illustrated by way of non-limiting example in the accompanying drawings, wherein:
With reference to the figures, the reference numeral 1 generally designates a break-in resistant lock.
The lock 1 comprises a box-like body 2 for accommodating a plurality of contoured plates 3 which are provided with a respective portion (not visible in the figure) suitable for detachable engagement on a corresponding area of a movable rod 4, which supports, at its free end 5, at least one bolt 6 which can retract jointly with the rod 4.
With particular reference to the embodiment shown in the accompanying figures, the rod 4 supports (with its end 5) four bolts 6 arranged in a parallel configuration.
The plates 3 can perform a vertical translational motion by way of the action of the key (not visible in the figure), and are designed to release the translational motion, when they are lifted, of the rod 4 and accordingly of the bolt 6 for their retraction and protrusion.
At least one of the plates 3 is constituted by a respective rear plate 7 (a plate 7 which is adapted to cooperate directly with the rod 4 for the translational motion of the bolts 6) and a respective front tumbler 8 (the lower surface 8a of which constitutes the abutment against which the surface of the key acts during the actuation of the lock 1).
The plate 7 and the tumbler 8 are mutually coupled by means of a complementarily shaped contoured portion which is provided on their mutually facing edges 9: the contoured portion (which is zigzag-shaped in the accompanying figures) is designed to allow to mutually couple the plate 7 and the tumbler 8 according to a plurality of different configurations, ensuring the possibility to code the lock 1. The new coding must be performed according to the typical methods of the particular lock 1 being used, by using a suitable key or a specific tool.
The front tumbler 8 comprises a protruding arm 10, which is interposed between the front of the rear plate 7 and a protective housing 11.
The arm 10, in order to ensure the best possible resistance against break-in actions, has a shape and dimensions which are complementary to the interspace provided between the plate 7 and the housing 11 in order to prevent accessibility to the plate 7 with break-in tools.
In traditional locks it is possible to interpose a break-in tool between the housing 11 and the traditional tumblers: in this manner, the tool can come into contact with the plates 7, producing their translational motion. This translational motion releases the rod 4 and therefore allows the retraction of the bolts 6.
The presence of the arm 10 of the tumbler 8 makes it impossible to access the plates 7 and therefore thwarts any break-in attempt.
The protruding arm 10 is arranged downward and laterally with respect to the front tumbler 8.
It should be noted that according to an embodiment which is particularly interesting in terms of application, at least two of the various tumblers 8 that are present in the respective contoured plates 3 have a protruding arm 10.
According to a particular embodiment which is adapted to ensure maximum safety of the lock 1 according to the invention with respect to break-in actions, all the tumblers 8 of the contoured plates 3 have a respective protruding arm 10.
The portion 12 of the protective housing 11 faces and lies proximate to the end 13 of the arm 10 which is jointly connected to the tumbler 8.
The portion 12 tapers toward the end 13 and its tip 14 rests against (or faces and is proximate to) the end 13.
More particularly, the end 13 comprises an abutment 15 (constituted by a small substantially flat step) for stable resting with a complementary arrangement of its surface with respect to the surface of the tip 14 of the housing 11.
The abutment 15, according to an alternative embodiment, can simply face and be proximate to the surface of the tip 14.
According to a possible embodiment, the arm 10 can be rigidly coupled to the tumbler 8 at the end 13 by way of suitable anchoring means. It should be noted that the tumbler 8 generally comprises the arm 10: accordingly, they are formed monolithically.
It has thus been shown that the invention achieves the proposed aim and objects.
The invention thus conceived is susceptible of numerous modifications and variations, as defined by the appended claims.
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.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.