Double-bit safety lock

Abstract

 The lock comprises a box-shaped body (10) inside which a bolt (12) slidable along a first direction and a set of adjacent tumblers (14a, 14b) movable along a second direction orthogonal to the first direction are housed. Each tumbler (14a, 14b) has a toothed opening (30), a recess (26) and an upper slot (22) and a lower slot (24). A pin (44) protruding transversally from the bolt (12) passes through all the openings (30); a first guiding pin (40) fixed to the box-shaped body (10) passes through all the upper slots (22) and a second guiding pin (42) fixed to the box-shaped body (10) passes through all the lower slots (24). The lock also comprises: an auxiliary element (36) having an eyelet-shaped through-hole (38) and arranged within the upper slot (22) of at least one tumbler (14b), the first guiding pin (40) passing through the eyelet-shaped hole (38); and a device which is associated with the box-shaped body (10) and is suitable for stopping any movement along the second direction of the tumbler (14b), inside the upper slot (22) of which the auxiliary element (36) is inserted.

Description

[0001] The present invention relates to double-bit locks which are typically used in environments where it is required to ensure the greatest possible protection against attempted break-ins.

[0002] As is well-known, such a lock comprises a box-shaped body inside which a bolt slidable along a first direction and a set of adjacent tumblers (or "gorges") movable along a second direction orthogonal to the first direction are housed, each tumbler having a toothed opening, a recess and an upper slot and a lower slot. Moreover, a pin (or "mentonnet") which protrudes transversely from the bolt passes through all the openings, a first guiding pin fixed to the box-shaped body passes through all the upper slots and a second guiding pin fixed to the box-shaped body passes through all the lower slots.

[0003] Moreover, in recent times increasingly more sophisticated fraudulent opening systems have been developed, in particular of the "sensing" type which envisage the use of tools designed to decipher the coding of the lock, making it even possible to duplicate the key. Basically, these techniques are implemented by inserting simultaneously into the key-hole of the lock a first tool which pushes the bolt and second tool able to sense, in sequence, the configuration of the teeth in the openings present in each tumbler.

[0004] The prior art documents EP-903 455 and WO-2009/057170 describe locks provided with security devices which are designed to prevent attempted break-ins performed using the "sensing" technique. These security devices are typically incorporated in the lock at the time of its manufacture, it thus being practically impossible to incorporate them into pre-existing locks.

[0005] The object of the present invention is therefore to provide a lock able to withstand effectively fraudulent opening attempts by means of sensing, overcoming the drawbacks of the prior art.

[0006] This object is achieved by means of a lock of the type indicated at the start of the present description and characterized in that it also comprises:

• an auxiliary element having an eyelet-shaped through-hole and arranged within the upper slot of at least one of said tumblers, the first guiding pin passing through said eyelet-shaped hole, and
• a device which is associated with the box-shaped body and is suitable for stopping any movement (due to tampering) along a second direction of the at least one tumbler inside the upper slot of which said auxiliary element is inserted.

[0007] In the case where a sensing tool is used, this tends to cause, instead of displacement in the vertical direction of the tumbler with which the auxiliary element is associated, its displacement with a horizontal component, this being made possible by the presence of the eyelet-shaped hole; the latter in fact slides with respect to the pin which is thus prevented from performing its function of guiding the movement in the vertical direction. The displacement of the tumbler with a component in the horizontal direction, which may thus be defined as floating, causes it to bear against the catch device and consequently to be locked in position. In this way sensing is prevented and any attempt to decipher the coding of the lock is thwarted.

[0008] The lock according to the invention has external dimensions equivalent to those of a conventional lock, reproducing to a large extent the general structure of the latter with minimal and low-impact modifications. Consequently, it offers the advantage of ensuring the abovementioned security, without the need for manufacturing technology substantially different from conventional technology and without generating additional costs.

[0009] The lock according to the invention has the advantage that it may be made from a conventional non-security lock in a very simple manner. For this purpose it is in fact sufficient to replace the internal tumblers of the lock with modified tumblers which have a wider upper slot so as to be able to house the abovementioned auxiliary element, and further to fix the aforementioned catch device inside the box.

[0010] The present invention therefore also relates to a kit for upgrading conventional locks, which can be installed in a simple and easy manner and which comprises the modified tumblers, the auxiliary element and the catch device.

[0011] Further advantages and characteristic features of the present invention will become clear from the detailed description which follows, provided purely by way of a non-limiting example with reference to the accompanying drawings in which:

Figure 1 is a schematic elevation view of a lock according to the invention, which shows in particular the structure of one of the external tumblers of the set, some components having been omitted for greater clarity;

Figure 2 is a schematic elevation view, corresponding to Figure 1, which shows in particular the structure of one of the internal tumblers of the set;

Figures 3 and 4 are perspective views, from different angles, of components of the lock of the preceding figures;

Figure 5 is an elevation view of an external tumbler of the lock according to the preceding figures;

Figure 6 is an elevation view of an internal tumbler of the lock according to the preceding figures;

Figure 7 is an elevation view of an internal tumbler in relation to other components of the lock according to the preceding figures;

Figures 8 to 11 are schematic views, corresponding to Figure 1, which show respective successive steps of the closing movement of the lock according to the invention;

Figure 12 is a perspective view of a component of the lock according to the invention;

Figure 13 is a plan view of the catch member of the lock according to the invention;

Figure 14 is a side elevation view of the catch member of the lock according to the invention;

Figure 15 is a front elevation view of the catch member of the lock according to the invention;

Figure 16 is a cross-sectional view along the line XVI-XVI of Figure 14; and

Figure 17 is a cross-sectional view along the line XVII-XVII of Figure 13.

[0012] A security lock comprises (Figs. 1-7) a box-shaped body 10 which houses a bolt 12 slidable along a first substantially horizontal direction and a set of adjacent tumblers 14a, 14b normally movable along a second substantially vertical direction, orthogonal to the first direction.

[0013] In a manner known per se, the bolt 12 comprises a body or carrier in which a recess 16 is formed and from which there protrudes a plurality of locking heads 20 able to penetrate inside seats formed in a wall which defines an aperture closed by a shutter on which the lock is mounted (not shown in the figures). A key 18 rotated by a user may act on the edges of the recess 16 so as to open/close the lock.

[0014] The set of tumblers 14a, 14b is formed by two external tumblers 14a and four internal tumblers 14b. In embodiments not shown, the number of tumblers 14a, 14b could be different, for example between 3 and 9, in particular between 5 and 7.

[0015] Each external tumbler 14a - the structure of which is entirely conventional - has a substantially rectangular form with a perimeter formed by two long sides and two short sides. An upper slot 22 and a lower slot 24 are formed in the two short sides, respectively. A recess 26, on the edge of which the bit of the key 18 may act, is formed in one of the long sides. Each tumbler 14a also has a generally rectangular-shaped opening 30, the long sides of which have projecting teeth 32 and are parallel to the short sides of the tumbler 14a.

[0016] Each internal tumbler 14b has a structure which corresponds exactly to that of the external tumblers 14a, except for the fact that its upper slot 22 has a width greater than the width of the upper slot 22 of the external tumblers 14a and that the long side opposite to that in which the recess 26 is formed has a knurled upper section 34. A respective wire spring 28 normally biases each tumbler 14a, 14b downwards.

[0017] An auxiliary element 36 (Fig. 12) which has a parallelepiped shape and has a substantially horizontal eyelet-shaped through-hole 38 is located inside the upper slot 22 of all the internal tumblers 14b.

[0018] A first guiding pin 40 fixed to the box-shaped body 10 passes through the upper slots 22 of all the tumblers 14a, 14b, and in particular through the eyelet-shaped hole 38 of the auxiliary element 36 inserted inside the slots of the tumblers 14b. In particular, the upper slots 22 of the external tumblers 14a have a width corresponding to that of the pin 40, which is instead smaller than the width of the eyelet-shaped hole 38.

[0019] On the other hand, a second guiding pin 42 fixed to the box-shaped body 10 passes through the lower slots 24 of all the tumblers 14a, 14b, the width of which corresponds to that of the pin 42.

[0020] A pin 44, which protrudes transversely from the carrier of the bolt 12, passes through the openings 30 of all the tumblers 14a, 14b.

[0021] A catch device is associated with the box-shaped body 10 and comprises (Figures 13-17) a first element 46 fixed by means of screws 48 to the box-shaped body 10 and a second element 50 pivoted under the biasing action of elastic means, such as a helical spring 52, inside a cavity of the first element 46 about a pivot 54. The bottom wall of the cavity is inclined slightly so as to allow a slight rotation of the element 50 about the pivot 54 which passes through the holes formed in the two elements 46, 50. The second element 50 has, on the edge facing the internal tumblers 14b, a knurling 56 suitable for coupling with the knurled upper section 34 formed on one side of said tumblers.

[0022] Normal operation of the lock is entirely conventional, so that it is only briefly described. Firstly, the key 18 which has a double bit with a certain profile of recesses and projections is inserted inside the keyhole and is rotated. The interaction of one of the bits of the key 18 with the edge of the recesses 26 causes, during a first arc of rotation through about 90° (Fig. 8), the movement of the tumblers 14a, 14b in the second direction, namely the vertical direction, which is guided by the engagement of the pins 40, 42 inside the upper slots of the external tumblers 14a, and inside the lower slots of all the tumblers 14a, 14b, respectively, although being of a different magnitude for the single tumblers 14a, 14b depending on the shape of the bit of the key 18. Following this movement, the openings 30 in the tumblers 14a, 14b are positioned so that the pin 44 has immediately in front of it a free section of all the openings 30, namely without projecting teeth 32. Therefore, during the subsequent arc of rotation through about 90° the key 18, which biases the edge of the recess 16 formed in the carrier of the bolt 12, causes the displacement of the latter since the pin 44 integral therewith may freely move along the first section of the openings 30 without being hindered by any projecting tooth 32. Consequently, the teeth 20 of the bolt 12 move over a corresponding length (Fig. 9). The operations described above correspond to one turn, or a rotation of the key 18 through a plane angle, and must be repeated (Figures 10, 11) for the number of turns necessary to cause complete opening/closing of the lock, which depend on the length of the openings 30.

[0023] In the event of an attempted break-in by means of "sensing", the thief inserts simultaneously into the key-hole of the lock a first tool which pushes against the recess 16 in the carrier of the bolt 12 and a second tool able to detect the configuration of the teeth in the openings 30 of the tumblers 14a, 14b.

[0024] In this case, the second tool acts in each case on the various tumblers of the set with incorrect coding heights. Therefore, when it acts on one of the internal tumblers 14b, the latter moves independently of the other ones without being able to be guided by the pin 40 relative to which the eyelet-shaped hole 38 moves and which could only act as a guide for its movement when there was a correct movement also of the external tumblers 14a of the set, the upper slot 22 of which has a width corresponding to the size of the pin 40 which thus acts as a guide. Consequently, the tumbler 14b, instead of moving in the vertical direction, allowing deciphering of its coding, performs a movement with a horizontal component which is made possible by the presence of the eyelet-shaped hole 38. This displacement in the horizontal direction causes coupling of the knurled upper section 34 of one side thereof with the knurling 56 of the second element 50 of the catch device. The element 50 may pivot slightly around the pivot 54 so as to allow perfect mating of the knurlings 34, 56 which opposes even more effectively displacement of the tumbler 14b. In this way, sensing is prevented and any attempt at deciphering the coding is thwarted.

[0025] It should be noted that a conventional lock may be easily converted into a lock according to the invention, by simply replacing the internal tumblers with modified tumblers 14b as described above and adding thereto the auxiliary element 36 and the catch device.

[0026] In principle, it is possible to modify one or more tumblers, except for one. In practice, in order to achieve a satisfactory compromise between the need for security and mechanical functionality, it is advisable to modify all the internal tumblers 14b, leaving the external tumblers 14a unchanged.

[0027] Obviously, without affecting the principle of the invention, the constructional details and the embodiments may be greatly varied with respect to that described purely by way of example, without thereby departing from the scope thereof.

Claims

1. Security lock comprising a box-shaped body (10) inside which a bolt (12) slidable along a first direction and a set of adjacent tumblers (14a, 14b) movable along a second direction orthogonal to the first direction are housed, each tumbler (14a, 14b) having a toothed opening (30), a recess (26) and an upper slot (22) and a lower slot (24), a pin (44) protruding transversally from the bolt (12) passing through all the openings (30), a first guiding pin (40) fixed to the box-shaped body (10) passing through all the upper slots (22) and a second guiding pin (42) fixed to the box-shaped body (10) passing through all the lower slots (24), said lock being characterized in that it further comprises:

- an auxiliary element (36) having an eyelet-shaped through-hole (38) and arranged within the upper slot (22) of at least one of said tumblers (14b), the first guiding pin (40) passing through said eyelet-shaped hole (38), and

- a device which is associated with the box-shaped body (10) and is suitable for stopping any movement along said second direction of the at least one tumbler (14b), inside the upper slot (22) of which said auxiliary element (36) is inserted.

2. Lock according to Claim 1, wherein said first direction is substantially horizontal and said second direction is substantially vertical.

3. Lock according to Claim 1 or 2, wherein each tumbler (14a, 14b) is substantially rectangular-shaped with a perimeter formed by two long sides and two short sides, the upper slot (22) and the lower slot (24) being formed respectively in said short sides, said recess (26) being formed in one of the long sides and said opening (30) being generally rectangular-shaped, the long sides thereof having teeth (32) and being parallel to the short sides of the tumbler (14a, 14b).

4. Lock according to any one of the previous claims, wherein said auxiliary element (36) is parallelepiped-shaped.

5. Lock according to any one of the previous claims, wherein said auxiliary element (36) is inserted within the upper slot (22) of all the internal tumblers (14b) of the set, the width of which is greater than the width of the upper slot (22) of the external tumblers (14a), which corresponds to the size of the respective guiding pin (40).

6. Lock according to any one of the previous claims, wherein the number of said tumblers (14a, 14b) ranges between 3 and 9, preferably between 5 and 7.

7. Lock according to any one of the preceding Claims 3 to 6, wherein a long side of the at least one tumbler (14b), inside the upper slot (22) of which said auxiliary element (36) is inserted, has an upper knurled section (34) suitable for coupling with a complementary knurling (56) of the catch device.

8. Lock according to any one of the preceding claims, wherein said catch device comprises a first element (46) fixed to the box-shaped body (10) and a second element (50) pivoted on the first element (46) about a pivot (54).

9. Lock according to Claim 8, wherein said second element (50) is equipped with elastic biasing means.

10. Lock according to Claim 8 or 9, wherein said second element (50) has a knurling (56) on an edge facing said at least one tumbler (14b).

11. Lock upgrading kit for providing a security lock according to any one of the preceding claims, comprising:

- a plurality of tumblers (14b), each of which has a toothed opening (30), a recess (26) and an upper slot (22) and a lower slot (24);

- an auxiliary element (36) which has an eyelet-shaped through-hole (38) and is designed to be arranged inside the upper slot (22) of said tumblers (14b); and

- a device to be associated with the box-shaped body (10) of the lock, which is suitable for stopping the movement of the tumblers (14b).

Drawing