SECURE FILTER LOCK CYLINDER

Abstract

The invention relates to a lock cylinder (10) designed to allow the passage of a key to actuate a locking mechanism. It comprises an entry (12) and an exit (18); a set (16) of washers between said entry (12) and said exit (18) to define a passage path; a first key (26); and a second key (40), said key being designed to be rotated within said passage path to cause said first (26) and second (40) keys to pivot so that said second key (40) releases said first key (26), thereby allowing the passage of said key through said exit (18). One of said first (26) and second (40) keys has a groove (34), while the other of said first and second keys has a stud (50).

Description

[0001] The present invention relates to a filter lock cylinder intended to allow the passage of a key to then allow the actuating of a locking mechanism by rotating the key.

[0002] Known cylinders have, on the one hand, an entry flange with an entry slot and an opposite exit flange with an exit slot offset angularly by approximately 90° relative to the entry slot, and on the other hand, a set of washers stacked between the entry and exit flanges to define a conditioned passage path for the key between the entry and exit slots. The passage path defined by the washers is conditioned by whether or not it allows the key bit to rotate through the set of washers by approximately 90°.

[0003] The washers have radially extended portions projecting towards the center of the passage path. Therefore, a key whose bit has radial notches for coding is permitted to rotate through the washer set if the notches in the bit and the projecting portions of the washers coincide.

[0004] Furthermore, the cylinder includes a set of three controllable keys that close the exit slot. Each key in the set comprises a control shaft extending axially towards the entry flange and a lever integral with the control shaft. The lever extends radially within the conditioned passage path to engage with the key's bit.

[0005] The key set comprises, on the one hand, a first pivoting movable key, intended to close the exit slot, and on the other hand, a second pivoting movable key, forming a hook, intended to retain the first key and a third pivoting movable key, opposite the second key, and intended to form a support to prevent the movement of the first key.

[0006] Thus, if the rotation of the cam and the key is permitted, the cam sequentially causes the second and third keys to pivot. As these keys move away from the first key, they are released, which is then in turn pivoted to free the exit slot. Consequently, the cam can be driven through the exit slot beyond the flange, thereby actuating a locking mechanism located behind the exit flange.

[0007] Reference can be made to document FR 2 734 858 describing such a type of lock cylinder.

[0008] These lock cylinders are relatively secure. However, they can be picked.

[0009] Also, a problem that arises and that the present invention aims to solve is to provide a lock cylinder that is more difficult to pick.

[0010] To this end, a filter lock cylinder is proposed, designed to allow the passage of a coded key to operate a locking mechanism, said lock cylinder comprising: an entry and an exit opposite said entry; a set of stacked washers located between said entry and said exit to define a conditioned passage path of said key; a first movable key pivoting between a position where it blocks said exit and a position where it is away from said exit;and, a second movable key intended to retain said first key when said first key blocks said exit, said coded key being intended to be rotated within said passageway in order to rotate said first and second keys so that said second key releases said first key so that said first key moves away from said exit, thus allowing passage of said key through said exit. One of said first and second keys has a groove, while the other of said first and second keys has a pin, so that said second key releases said first key if and only if said pin engages within said groove when said first and second keys pivot.

[0011] Thus, a feature of the invention lies in the implementation of a groove in one of the keys and a pin in the other key, such that the pivoting of the first key, which obstructs the exit, is possible only if the pin engages inside the groove. Otherwise, the pin of the other key retains it. Whereas in lock cylinders according to the prior art, the pivoting of the second key alone, until it releases the first key, allowed the first key to pivot, according to the invention, the pivoting of the second key must occur within a specific angular sector. Thus, only one angular position of the second key allows the pivoting of the first. Consequently, it is much more difficult to find this single position of the second key blindly, using hooks.

[0012] According to a particularly advantageous embodiment of the invention, the first key has the groove, while the second key has the pin. Thus, the first key, which closes the outlet, has a larger overlap surface than the second key. In this way, it is easier to form the groove on this first key. Advantageously, the first key has two opposing surfaces, and the groove is formed in one of these surfaces. As will be explained below in the detailed description, the first key has a surface extending opposite the cylinder outlet and a surface opposite the outlet, and the groove for receiving the pin is formed in the opposite surface. Therefore, the second key is designed to pivotally rotate with respect to the opposite surface of the first key.

[0013] Furthermore, the lock cylinder advantageously includes a third movable key designed to pivot and retain the first key. This third key is mounted opposite the second key relative to the first key and acts as a support to retain the first key. It is designed to pivot between the exit and the first key, specifically opposite the surface of the first key which is oriented towards the exit of the lock cylinder.

[0014] Preferably, one of the first and third keys has another groove, while the other of the first and third keys has another pin, such that the third key releases the first key if and only if the other pin engages within the other groove. In this way, an additional constraint is added to allow the lock cylinder to exit, namely the relative position of the third key and the first key so that the other pin engages in the other groove; otherwise, the first key remains held against the exit.

[0015] Advantageously, the first key has the other groove, while the third key has the other pin. Thus, the first key has both grooves, while the second and third keys each have one pin.

[0016] Also, the said keys are movable by pivoting, preferably, along planes substantially perpendicular to said passage path. When the three keys are in use, the second and third keys are able to pivot on either side of the first key along substantially parallel planes.

[0017] Furthermore, each of said keys comprises a control shaft extending axially outside said keyway, and said control shaft includes a lever extending radially inside said keyway. In this way, the key bit is able to cooperate with the levers of the control shafts of the keys so as to cause them to pivot when rotation of the key is permitted.

[0018] Also, the first key has a proximal portion and a distal portion extending in a step relative to the proximal portion. As will be explained below, the two stepped spaces thus created allow the second and third keys to be received.

[0019] Furthermore, said second key has a hooked end, and said distal part is intended to engage with said hooked end to retain said first key.

[0020] Other features and advantages of the invention will become apparent from the following description of a particular embodiment of the invention, given by way of example but not limitation, with reference to the attached drawings in which: there Figure 1 is a partial schematic three-quarter front view of a lock cylinder according to the invention; the Figure 2 is a partial schematic three-quarter rear view of the lock cylinder shown on the Figure 1 , in a first state; the Figure 3 is a partial schematic rear view of the lock cylinder shown on the Figure 2 , in a second state; the Figure 4 is a partial schematic three-quarter rear view of the lock cylinder shown on the Figure 2 , in an intermediate state between the first and second states; and, the Figure 5 is a partial schematic three-quarter rear view of the lock cylinder shown on the Figure 2 , in another intermediate state.

[0021] There Figure 1 The figure illustrates a lock cylinder 10 according to the invention. It has an entrance 12 into which a shaft 14 of a key 15 is engaged. The entrance 12 is formed by a transverse slot through which the key 14 is inserted. The lock cylinder 10 includes a set 16 of stacked washers, defining a keyway, between the entrance 12 and the exit 18 of the cylinder 10, which appears on the Figure 3 , where it is viewed from the rear. The keyway defined by the stacked washers is coded to allow or prevent the rotation of key 15. The following then appear on this Figure 3 , besides the exit 18 forming a slot, and under conditions which will be described below, a key end 20 and two cams 22, 24 symmetrical to each other with respect to the rod 14. The key end 20 and the cams 22, 24 are here again located inside said passageway and have not yet passed through exit 18.

[0022] We will refer to the Figure 2 The image shows, from a three-quarter rear view and partially, the lock cylinder 10. The transverse slot 18 is then completely closed by a first key 26. This key has a proximal portion 28 forming a bent arm and a substantially trapezoidal distal portion 30. These two portions 28 and 30 each have a thickness e. The proximal portion 28 is integral with a first control shaft 32, which extends axially around the periphery of the set 16 of stacked washers. Also, the distal part 30 is mounted in a step on the proximal part 28. Thus, the first key 26 has a proximal step extending opposite the outlet 18 and a distal step extending opposite the outlet 18. Also, the proximal part 28 has an external groove 34, opening into its upper edge 35, while the distal part 30 has an internal groove 36 opening into its upper edge 38.

[0023] Also appearing on this Figure 2 , a second key 40 opposed to a third key 42. The second key 40 has a second proximal end 44 attached to a second control axis 46, and opposite, a second distal end 48 forming a hook. This second distal end 48 extends into the proximal recess, the thickness of which is approximately equal to the thickness of the distal portion 30 of the key 26. The hooked distal end 48 is thus engaged in one of the corners of the distal portion 30 of the key 26. In this position, the second key 40 holds the first key 26 in a fixed position across the outlet 18. Furthermore, the second key 40 has a second lug 50, extending from the distal end 48 towards the outlet 18. The second lug 50 also bears against the upper edge 35 of the proximal portion 28 of the first key 26.Therefore, thanks to the second nipple 50, the first key 26 is also retained.

[0024] The third key 42 has a third proximal end 52 integral with a third control axis 54, and a third distal end 56 opposite it. The third control axis 54 is diametrically opposite the second control axis 46, and they extend parallel to each other. The third distal end 56 extends into the distal recess and has a third lug 58 opposite the outlet 18. The third lug 58 bears against the upper edge 38 of the distal portion 30 and, thereby, also holds the first key 26 in a fixed position, acting as a support.

[0025] The three control axes 32, 46, and 54 extend axially outside the keyway and each has a lever, not shown, extending inside the keyway. The cams 22, 24 of the key 15 are adapted to cooperate sequentially with the levers of the three control axes 32, 46, 54, if rotation of the rod 14 is permitted, in order to pivotally drive, in a first phase, the second 40 and third 42 keys and then in a second phase, the first key 26.

[0026] Therefore, we will refer to the Figure 4 , on which the second 40 and third 42 keys were driven in pivot according to this first phase, in a clockwise direction according to the view shown in the Figure, by a determined amplitude so that, on the one hand, the second pin 50 comes opposite the external groove 34 opening into the upper edge 35 of the proximal part 28, and on the other hand, the third pin 58 comes opposite the internal groove 36. Sequentially, by continuing the rotation of the key 15 inside the key passage path, one of the cams 22, 24 cooperate with the lever of the first control shaft 32, and thereby drives in pivot still in a clockwise direction the first key 26, which is allowed.

[0027] Indeed, the second 50 and third 58 lugs then respectively engage in the external 34 and internal 36 grooves, as the first key 26 pivots. It then continues its travel, until it releases the outlet 18, as illustrated by the Figure 3 already mentioned. We will refer to it again.

[0028] We find on this Figure 3 the first key 26 completely removed from the output 18 and thus revealing the end of the key 20 and the two cams 22, 24.

[0029] Also shown in dashed lines is the third pin 58 of the third key 42, which has slid into the internal groove 36 of the first key 26 as it pivoted. Simultaneously, the second pin 50 of the second key 40 has engaged in the external groove 34 of the first key 26. With these keys 26, 40, and 42 in this position, separated from the output 18, the key 15 can be pushed in further so that the end of the key 20, and especially the two cams 22 and 24, are driven past the keys 26, 40, and 42 towards a locking device (not shown) so that it can be actuated by a further rotation of the key 15.

[0030] Obviously, the keys 26, 40, 42 are kept away from the outlet 18, thanks to the first key 26 which rests on the rod 14 and which holds the other two keys 40, 42. Also, the cams 22, 24 and the end of the key 20 can be removed before the keys 26, 40, 42 return by pivoting to their initial position of closing the outlet 18.

[0031] Thus, this type of filtered lock cylinder is more difficult to pick compared to prior art cylinders of the same type. Indeed, in order to release the exit 18 by rotating the first key 26, it is necessary to precisely align the other two keys 40 and 42 so that the second 50 and third 58 pins are precisely aligned with the second 34 and third 36 grooves, respectively. Then, the first key 26 must be rotated. Such a blind operation is virtually impossible. This makes this type of lock cylinder much more secure than prior art cylinders.

[0032] For example, by referring to the Figure 5, it is understood that if the third key 42 is driven into pivoting with too great an amplitude, the third stud 58 remains in contact with the upper edge 38 of the distal part 30 and thereby prevents the pivoting of the first key 26.

Claims

1. A lock cylinder with a filter (10) intended to allow a coded key (15) to pass through in order to actuate a locking mechanism, said lock cylinder (10) comprising : an inlet (12) and an outlet (18) opposed to said inlet; a set (16) of stacked washers located between said inlet (12) and said outlet (18) to define a conditioned pathway for said key (15) ; a first wedge (26) swivelingly movable between a position where it closes said outlet (18) and a position where it is spaced apart from said outlet (18) ; and, a second swivelingly movable wedge (40) intended to hold said first wedge (26) when said first wedge (26) closes said outlet (18), said coded key (15) being intended to be rotated inside said pathway to be able to swivelingly drive said first (26) and second (40) wedges in order that said second wedge (40) releases said first wedge (26) such that said first wedge (26) moves away from said outlet (18), in order to allow said key (15) to pass through said outlet (18) ; characterized in that one of said first (26) and second (40) wedges is provided with a groove (34), while the other of said first and second wedges is provided with a pin (50), such that said second wedge (40) releases said first wedge (26) if and only if said pin (50) engages into said groove (34) when said first (26) and second (40) wedges swivel.

2. The lock cylinder according to claim 1, characterized in that said first wedge (26) is provided with said groove (34), while said second wedge (40) is provided with said pin (50).

3. The lock cylinder according to claim 2, characterized in that said first wedge (26) has two opposed surfaces and in that said groove (34) is provided within one of said surfaces.

4. The lock cylinder according to any of claims 1 to 3, characterized in that it further includes a third swivelingly movable wedge (42) intended to hold said first wedge (26).

5. The lock cylinder according to claim 4, characterized in that one of said first (26) and third (42) wedges is provided with another groove (36), while the other of said first and third wedges is provided with another pin (58), in such a manner that said third wedge (42) releases said first wedge (26) if and only if said another pin (58) engages into said another groove (36).

6. The lock cylinder according to claim 5, characterized in that said first wedge (26) is provided with said another groove (36), while said third wedge (42) is provided with said another pin (58).

7. The lock cylinder according to any of claims 1 to 6, characterized in that said wedges (26, 40, 42) are swivelingly movable with respect to planes substantially perpendicular to said pathway.

8. The lock cylinder according to any of claims 1 to 7, characterized in that each one of said wedges (26, 40, 42) comprises a control shaft (32, 46, 54) extending axially outwards said key pathway and in that said control shaft includes a lever extending radially within said key pathway.

9. The lock cylinder according to any of claims 1 to 8, characterized in that said first wedge (26) has a proximal part (28) and a distal part (30) that extend recessed with respect to said proximal part (28).

10. The lock cylinder according to claim 9, characterized in that said second wedge (40) comprises a hook end (48) and in that said distal part (30) is intended to engage said hook end (48) in order to hold said first wedge.