EP3505709B1

EP3505709B1 - Secure smart lock

Info

Publication number: EP3505709B1
Application number: EP17306968.3A
Authority: EP
Inventors: Damien Fauvel; Minglai CHEN; Romain CAZALIS; Martin LESPINASSE; Frédéric Potter
Original assignee: Netatmo SAS
Current assignee: Netatmo SAS
Priority date: 2017-12-28
Filing date: 2017-12-28
Publication date: 2020-04-29
Anticipated expiration: 2037-12-28
Also published as: EP3505709A1

Description

FIELD

The invention relates to the field of secure key control and concerns a lock mechanism designed to prevent its opening when the outer portion is submitted to vibrations.

BACKGROUND

Electromechanical lock and key with identification code are widespread. Such a lock mechanism is disclosed in e.g. WO2014/016283A1 . They enable authorized key holders to have access to locked rooms if the identification code of the key corresponds to a predetermined code in relation with the electromechanical lock. The key may be an ordinary locking key to insert into the lock or an access badge to pass in front of the lock.
The electromechanical lock comprises a processor configured to compare the identification code of the key with the predetermined code. If the identification code corresponds to the predetermined code, the electromechanical lock switches from its locked state to its unlocked state.
Generally, locks are formed with a body that can be easily unscrewed by a locksmith to facilitate rekeying. The body has the function to lock and unlock the lock. A lock body may be found under the form of a European cylinder (defined by the DIN18251). A European cylinder is a type of lock cylinder. There exist other profiles of lock bodies like the oval cylinder that is used in the Nordic countries. A body may not be in the form of a cylinder. A lock body may be inserted into a lock or a mortise lock or a slot-in lock. This function offers the advantage of allowing its change without altering the boltwork hardware. Removing the body typically requires only loosening a set screw, then sliding the body from the boltwork.
This type of electromechanical locks has the drawback that they are not totally safe. Indeed an ill-intentioned person may manage to unlock an existing lock by applying vibrations to the lock, for example by hitting the lock with a hammer. The internal mechanical elements of the lock slightly move because of the vibrations. While further submitted to vibrations, the internal mechanical elements may come into the position in which they cooperate to unlock the existing lock.
There is consequently a need for a lock mechanism configured to prevent its internal mechanical elements to come into their unlocking position of the lock mechanism when submitted to vibrations.

SUMMARY OF THE INVENTION

A new solution to overcome this drawback is a lock mechanism with an additional security feature, thus preventing the internal mechanical elements of the lock to cooperate when submitted to vibrations.
To this end, the subject of the invention is a lock mechanism comprising a housing, a lock clutch configured to cause the lock mechanism to switch between a locked state and an unlocked state according to a switching command received by the lock mechanism, a clutching mechanism mobile in rotation around a longitudinal axis and in translation with respect to the lock clutch according to the longitudinal axis and configured to be in an engaged position with the lock clutch so as to cause the lock mechanism to switch between the locked state and the unlocked state, or in a disengaged position from the lock clutch in the locked state, a first abutment against which the clutching mechanism abuts, the first abutment being mobile in translation with respect to the housing according to the longitudinal axis between the disengaged position and the engaged position according to the switching command, thus making the clutching mechanism mobile in translation between its disengaged position and its engaged position, a mechanical element extending along the longitudinal axis between the housing and the clutching mechanism, configured to maintain the clutching mechanism abutting against the first abutment in the engaged and disengaged position of the clutching mechanism, and in the disengaged position of the clutching mechanism in the locked state to absorb the mechanical energy due to vibrations to which the lock mechanism is submitted and retract.
According to an embodiment of the invention, the mechanical element may be a spring, a piston, a rubber element, or a magnet.
According to another embodiment of the invention, the lock mechanism is configured to cooperate with at least one identification key having an identification code and to switch from the locked state to the unlocked state if the identification code of the at least one identification key is an authorized code of the lock mechanism.
Advantageously, the lock mechanism comprises a processor configured to read the identification code of the at least one identification key, determine if the identification code is an authorized code of the lock mechanism and deliver the switching command if the identification code of the at least one identification key is an authorized code of the lock mechanism.
The lock mechanism may comprise a motor configured to move the first abutment between the disengaged position and the engaged position according to the switching command.
The invention also relates to a locking system comprising the lock mechanism according to the invention and the at least one identification key, wherein the at least one identification key comprises a transmitter of the identification code and the lock mechanism comprises a receiver of the identification code.
The at least one identification key may be an electronic key or a remote control.
In an embodiment of the invention, the at least one identification key is a smart phone configured to receive the identification code from an external connection or generate the identification code.
The invention also relates to a method for preventing a lock mechanism submitted to vibrations from switching between a locked state and an unlocked state, the lock mechanism comprising a lock clutch configured to cause the lock mechanism to switch between a locked state and an unlocked state, a clutching mechanism configured to be in an engaged position with the lock clutch so as to cause the lock mechanism to switch between the locked state and the unlocked state, or in a disengaged position from the lock clutch in the locked state, a mechanical element configured to absorb the mechanical energy due to vibrations, the method comprising a step of absorbing by the mechanical element the mechanical energy due to vibrations to which the lock mechanism is submitted in the disengaged position of the clutching mechanism in the locked state and retracting, so as to prevent the clutching mechanism from engaging with the lock clutch.
According to the invention, the mechanical element being a spring, the step of absorbing the vibrations comprises a step of retracting the spring.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various, non-limiting, exemplary, innovative aspects in accordance with the present descriptions :

Figures 1A, 1B, 1C schematically represent a first embodiment of a lock mechanism according to the invention;
Figures 2A, 2B, 2C schematically represent a second embodiment of a lock mechanism according to the invention;
Figures 3A, 3B, 3C schematically represent a third embodiment of a lock mechanism according to the invention;
Figures 4A, 4B schematically represent a fourth embodiment of a lock mechanism according to the invention;
Figures 5 and 6 schematically represent the method for absorbing vibrations applied to a lock mechanism.

For the sake of clarity, the same elements have the same references in the various figures.

DETAILED DESCRIPTION

Although many of the features of this invention are described in relation to a door, it is understood that they are generally applicable to any opening unit, such as a window. Moreover, these features are also applicable to many other devices, for example a padlock, having a locked state and an unlocked state.
In order to illustrate the invention, the explanations are related to a door. Note that these explanations may be applied similarly to any opening unit. A door is an opening unit enabling the access to a room (or from a room to the outside) through an aperture. The door is connected to a door frame that frames the aperture and is fixed to the walls around the aperture. In an unlocked state of the door, the door is mobile in relation to the door frame, typically mobile in rotation around doors hinges (or in translation in the case the door and the door frame being configured to let the door slide in relation to a part of the door frame and the wall). The door may be in an open configuration or a closed configuration. In the closed configuration, the door covers the aperture (i.e. no one can go through the aperture). Typically the door is equipped with a lock mechanism. The lock mechanism has a latch that is either inserted into a slot of the door frame (the door is closed) or retracted in the door (the door is not more fixed to the door frame and may be open). In the closed configuration, the latch is inserted into the slot of the door frame. In existing lock mechanisms, a lock clutch is connected to the latch. The lock clutch is usually engaged with both the indoor and outdoor door knobs. This enables a user to activate the lock clutch to cause the latch to move when a user moves one of the door knobs (or handles). Therefore a user has to move a door knob of the door to switch from the closed configuration of the door to the open configuration of the door. Indeed, the lock clutch being engaged with the knob, the movement of the knob generates a movement of the latch. Moving the door knob makes the latch retract into the door. The user can pull or push the door to open it.
In the closed configuration of the door (when the door is not open), the lock mechanism can be either in a locked state or an unlocked state. The unlocked state corresponds to the case discussed above. The door may be open by a user when activating a door knob and pushing or pulling the door. More precisely, the lock mechanism has a deadbolt entirely positioned inside the locking mechanism in the unlocked state. In the locked state, this deadbolt projects beyond the lock mechanism and is inserted into a slot of the door frame, thus locking the door to the frame. The movement of the deadbolt can be mechanically obtained, for example by a rotation of a key inserted into the locking mechanism. The rotation of the key clockwise, respectively anticlockwise, causes the deadbolt to translate either outside the lock mechanism to be inserted into the slot of the door frame, or inside the lock mechanism. To switch from the locked state of the door to the unlocked state of the door, a user has to rotate the key with the corresponding rotation of the key inside the lock mechanism. Afterwards, to open the door, the user has to move a door knob of the door, as explained before.
This previous case corresponds to a single-point lock mechanism (i.e. with a single deadbolt). The invention similarly applies to a multi-point lock mechanism. A multi-point lock, also known as a safety lock, provides extra security as it distributes the locking points (i.e. a plurality of deadbolts) over the entire door. The most common multi-point lock is the three-point lock composed of a main deadbolt in the center and two other bolts at the top and at the bottom actuated by a rod. Some multi-point locks may have up to ten locking points.
Figures 1A, 1B, 1C schematically represent a first embodiment of a lock mechanism 10 according to the invention. The lock mechanism 10 comprises a housing. The housing is commonly a cylinder extending along a longitudinal axis Z. The lock mechanism 10 comprises a lock clutch 11 configured to cause the lock mechanism 10 to switch between a locked state and an unlocked state according to a switching command 12 received by the lock mechanism 10. The lock clutch 11 may for example be in a contact with the deadbolt. When receiving the switching command 12, the lock clutch 11 causes the deadbolt to translate beyond the lock mechanism 10 to insert into a slot of the door frame, so as to switch from the unlocked state to the locked state of the lock mechanism 10. Or (depending on the command 12) the lock clutch 11 causes the deadbolt to translate inside the lock mechanism 10, so as to switch from the locked state to the unlocked state of the lock mechanism 10.
The lock mechanism 10 comprises a clutching mechanism 13 mobile in rotation around a longitudinal axis Z and in translation with respect to the lock clutch 11 according to the longitudinal axis Z and configured to be in an engaged position with the lock clutch 11, so as to cause the lock mechanism 10 to switch between the locked state and the unlocked state, or in a disengaged position from the lock clutch 11 in the locked state. The clutching mechanism 13 may be a star wheel or any gears. When in the engaged position with the lock clutch 11 (see Figure 1C), the protrusions of the clutching mechanism 13 (for example gear teeth) cooperate with the protrusions of the lock clutch 11. A rotation of the clutching mechanism 13 leads to a rotation of the lock clutch 11, to further translate the deadbolt, as mentioned before. In the disengaged position (see Figure 1A), the protrusions of the clutching mechanism 13 are not in contact with the protrusions of the clutch lock 11. Therefore no rotation of the lock clutch 11 may occur. The deadbolt cannot be translated.
The lock mechanism 10 further comprises a first abutment 14 against which the clutching mechanism 13 abuts. The first abutment 14 is mobile in translation with respect to the housing according to the longitudinal axis Z between the disengaged position and the engaged position according to the unlocking command 12, thus making the clutching mechanism 13 mobile in translation between its disengaged position and its engaged position. Since the clutching mechanism 13 abuts against the first abutment 14, the mobility in translation of the first abutment 14 enables the clutching mechanism 13 to cooperate with the lock clutch 11. Since both the clutching mechanism 13 and the lock clutch 11 have protrusions (such as gear teeth), the mobility in rotation around the longitudinal axis Z of the clutching mechanism 13 enables its right positioning in relation to the lock clutch 11 to ensure their engagement with each other.
The lock mechanism 10 comprises a mechanical element 16 extending along the longitudinal axis Z between the housing and the clutching mechanism 13, configured to maintain the clutching mechanism 13 abutting against the first abutment 14. The mechanical element 16 is configured to absorb vibrations to which the lock mechanism is submitted. The mechanical element 16 may be a spring, a piston, a rubber element or a magnet. Any other element able to absorb vibrations generated outside the lock mechanism may replace one of the above-mentioned mechanical elements.
The lock mechanism 10 according to the invention has the advantage that it cannot be unlocked by applying vibrations to the lock, for example by hitting the lock with a hammer. It is known that the internal mechanical elements of a lock slightly move when submitted to vibrations. While submitted to vibrations, the internal mechanical compounds of the lock mechanism 10 (i.e. the clutching mechanism 13 and the lock clutch 11) cannot come into the position in which they cooperate. Indeed, when the lock mechanism 10 is submitted to vibrations, the mechanical element 16 absorbs the mechanical energy due to the vibrations and retracts, as represented in Figure 1B. The mechanical element 16 has mechanical features chosen so that the absorption is performed in a given range corresponding to the field of application as it is known by a person skilled in the art. It results that the clutching mechanism 13 does not abut against the first abutment 14 anymore. And the clutching mechanism 13 cannot engage with the lock clutch 11. The lock mechanism according to the invention presents an additional security feature, all the more because the application of vibrations to the lock mechanism moves the clutching mechanism 13 away from the lock clutch 11.
In the embodiment presented in Figures 1A, 1B, 1C, the unlocking command 12 may result from an ordinary-looking key, the form of which being complementary to mechanical pieces inside the lock mechanism. The rotation of the ordinary-looking key may lead to the displacement of an element in connection with the first abutment 14, so as to cause it to translate.
Figures 2A, 2B, 2C schematically represent a second embodiment of a lock mechanism 20 according to the invention. The lock mechanism 20 represented in Figures 2A, 2B, 2C is identical to the lock mechanism 10 represented in Figures 1A, 1B, 1C. The lock mechanism 20 comprises the mechanical element 16 configured to absorb vibrations to which the lock mechanism 20 is submitted. The mechanical element 16 may be a spring, a piston, a rubber element or a magnet. Any other element able to absorb vibrations generated outside the lock mechanism may replace one of the above-mentioned mechanical elements. As explained before in relation to Figure 1B, when the lock mechanism 20 is submitted to vibrations, the mechanical element 16 absorbs the mechanical energy due to the vibrations and retracts, as represented in Figure 2B. The lock mechanism 20 is configured to cooperate with at least one identification key 21 having an identification code 22 and to switch from the locked state to the unlocked state if the identification code 22 of the at least one identification key 21 is an authorized code 23 of the lock mechanism 20.
The locking mechanism 20 according to the invention comprises a processor 24 configured to read the identification code 15 of the at least one identification key 14 and determine if the identification code 22 is an authorized code 23 of the locking mechanism 20. The processor 24 of the locking mechanism 20 comprises an algorithm that is able to generate a plurality of codes. When approaching an identification key 21 close to the locking mechanism 20 (i.e. until about 10 meters of the lock mechanism, for example thanks to the NFC™ or BLE™ technology, acronym of Bluetooth™ Low Energy technology), one of the codes generated by the algorithm of the processor 24 is transmitted from the processor 24 to the identification key 21. In return, the processor 24 should receive from the identification key 21 an authorized code, that is to say an identification code 22 corresponding to a code allowed by the processor 24. There is a communication between the locking mechanism 20 and the identification key 21. The locking mechanism transmits a code to the identification key. The identification key sends to the locking mechanism (i.e. to the processor) another code, as a response to the received code. And if the processor 24 receives from the identification key 21, as a response to its code, an authorized code, the identification key 21 is considered as an authorized key for switching the lock mechanism 13 between the locked and unlocked state. The processor 24 may deliver the command 12 if the identification code 22 of the at least one identification key 21 is an authorized code 23 of the lock mechanism. The communication between the identification key and the locking mechanism may be by direct contact, use an RF channel (NFC™, Wi-Fi™, Bluetooth™ or another standard or proprietary channel), an optical, magnetic or acoustical channel of communication.
Figures 2A, 2B, 2C schematically represent a locking system 50 comprising the lock mechanism 20 and the at least one identification key 21, wherein the at least one identification key 21 comprises a transmitter of the identification code 22 and the lock mechanism 20 comprises a receiver of the identification code 22. In Figures 2A, 2B, 2C, the identification key 21 is an electronic key.
Figures 3A, 3B, 3C schematically represent a third embodiment of a lock mechanism 30 according to the invention. The lock mechanism 30 represented in Figures 3A, 3B, 3C is identical to the lock mechanism 20 represented in Figures 2A, 2B, 2C. The lock mechanism 30 comprises the mechanical element 16 configured to absorb vibrations to which the lock mechanism 30 is submitted. The mechanical element 16 may be a spring, a piston, a rubber element or a magnet. Any other element able to absorb vibrations generated outside the lock mechanism may replace one of the above-mentioned mechanical elements. The lock mechanism 30 is configured to cooperate with at least one identification key 31 having an identification code 32. The identification key 31 is a remote control. The cooperation of a physical identification key with the locking mechanism comprises an insertion of the physical key into the key hole of the locking mechanism and an exchange of identification codes between the identification key and the processor of the locking mechanism. If the identification key is a remote control, the cooperation only comprises an exchange of identification codes between the identification key and the processor of the locking mechanism.
In this embodiment of the locking mechanism 30, the at least one identification key is a remote control 31 and the processor 34 is configured to receive from the remote control 31 the authorized code and deliver the command 12. The remote control 31 may be a smart phone or a tablet. The communication between the processor 24 and the remote control 31 may operate for example through Wi-Fi, NFC or Bluetooth™. The main advantage of this embodiment is the flexibility of the control. Indeed it is possible to deliver the command 12 thanks to the remote control 31. It is also possible to transfer the switching control to any other remote controls if needed. For example, a person waiting for a postal package in his/her absence may send to the postman an authorized code valid for a predetermined time period. The postman may use his own smart phone with the downloaded authorized code to make the clutching mechanism 13 of the locking mechanism 30 move into its engaged position with the lock clutch 11, so as to come in and deliver the postal package. And even if the postman does not make the lock clutch 13 switch back to its disengaged position, the processor 24 may be configured to send to the lock clutch 13 the command to switch back to its disengaged position, thus ensuring a high level of security, even if a person with a special authorization had a temporary control of the lock mechanism 30.
Figures 3A, 3B, 3C also schematically represent a locking system 60 wherein the at least one identification key 31 is a remote control 31. The remote control 31 is a smart phone configured to receive the identification code 32 from an external connection. The remote control 31 may also generate the identification code 32. For example, the smart phone 31 may comprise an algorithm configured to generate an authorized code based on the code received from the lock mechanism 30. Once the authorized code generated by the algorithm, the remote control transmits this authorized code to the processor of the lock mechanism. The processor of the lock mechanism determines if the received code from the remote control is an authorized code. If the received code is an authorized code, the processor considers that the remote control is an authorized key.
Figures 4A, 4B schematically represent a fourth embodiment of a lock mechanism 40 according to the invention. The lock mechanism 40 represented in Figures 4A, 4B is identical to the lock mechanism 30 represented in Figures 3A, 3B, 3C. The lock mechanism 40 comprises the mechanical element 16 configured to absorb vibrations to which the lock mechanism 40 is submitted. The mechanical element 16 may be a spring, a piston, a rubber element or a magnet. Any other element able to absorb vibrations generated outside the lock mechanism may replace one of the above-mentioned mechanical elements. The lock mechanism 40 comprises a motor 41 configured to move the first abutment 14 between the disengaged position and the engaged position according to the command 12.
In Figure 4A, the lock mechanism 40 is in a locked state. The clutching mechanism 13 is in a disengaged position with respect to the lock clutch 11. An authorized user wants to make the lock mechanism 40 switch from its locked state to its unlocked state (to open the door equipped with the lock mechanism 40). In Figure 4A, the identification key is a smart phone 31. The user brings the smart phone 31 in the vicinity of the lock mechanism 40. The processor 34 of the lock mechanism 40 generates a code and transmits it to the smart phone 31. As a response, the processor 34 of the lock mechanism 40 should receive an authorized code from the smart phone 31. The smart phone 31 may generate itself the authorized code, for example through the use of an adapted secure application. The smart phone 31 sends this code 32 back to the lock mechanism 40. The transmission of the code may be performed via any communication link, for example using Wi-Fi, NFC or Bluetooth™. The processor 34 of the lock mechanism 40 reads this code 32, determines if this code is an authorized code. If the code received from the smart phone 31 is an authorized code for the lock mechanism 40, the processor 34 delivers the command 12 to the motor 41. The motor 41 is activated to move the first abutment 14. The first abutment 14 is translated. Since the clutching mechanism 13 is maintained in abutment against the first abutment 14 due to the spring 16 (or any corresponding mechanical element), the clutching mechanism 13 of the locking mechanism 30 moves towards the lock clutch 11, following the translation of the first abutment 14. Thanks to its mobility in rotation around the longitudinal axis Z, the clutching mechanism 13 engages with the lock clutch 11. The clutching mechanism is in its engaged position with the lock clutch 11.
The invention advantageously offers a lock mechanism with an additional security feature. Thanks to the positioning of the clutching mechanism 13 between the first abutment 14 and the mechanical element 16 maintaining it against the first abutment 14, the engagement of the clutching mechanism 13 with the lock clutch 11 is only possible with a command of an authorized person. Such an engagement is not possible when the lock mechanism is submitted to vibrations.
Figures 5 and 6 schematically represent the method for absorbing vibrations applied to a lock mechanism according to the invention. The method comprises a step 100 of absorbing the vibrations to which the lock mechanism is submitted (illustrated by a hammer hitting the lock). In Figure 5, the mechanical element 16 is a piston that absorbs the mechanical energy due to the vibrations. The rod of the piston translates inside the cylinder, thus making the clutching mechanism translating away from the lock clutch. In Figure 6, the mechanical element 16 is a spring that absorbs the mechanical energy due to the vibrations. Submitted to the vibrations, the spring retracts. It results in the translating of the clutching mechanism away from the lock clutch, thus avoiding that the clutching mechanism and the lock clutch engage with each other.
The examples disclosed in this specification are therefore only illustrative of some embodiments of the invention. They do not in any manner limit the scope of said invention which is defined by the appended claims.

Claims

A lock mechanism (10, 20, 30, 40) comprising:
- a housing,

- a lock clutch (11) configured to cause the lock mechanism to switch between a locked state and an unlocked state according to a switching command (12) received by the lock mechanism,

- a clutching mechanism (13) mobile in rotation around a longitudinal axis (Z) and in translation with respect to the lock clutch (11) according to the longitudinal axis (Z) and configured to be in an engaged position with the lock clutch (11) so as to cause the lock mechanism to switch between the locked state and the unlocked state, or in a disengaged position from the lock clutch (11) in the locked state,

- a first abutment (14) against which the clutching mechanism (13) abuts, the first abutment (14) being mobile in translation with respect to the housing according to the longitudinal axis (Z) between the disengaged position and the engaged position according to the switching command (12), thus making the clutching mechanism (13) mobile in translation between its disengaged position and its engaged position,

- a mechanical element (16) extending along the longitudinal axis (Z) between the housing and the clutching mechanism (13), configured to maintain the clutching mechanism (13) abutting against the first abutment (14) in the engaged and disengaged position of the clutching mechanism (13) and in the disengaged position of the clutching mechanism in the locked state to absorb the mechanical energy due to vibrations to which the lock mechanism is submitted and to retract.
The lock mechanism (10, 20, 30, 40) according to claim 1, wherein the mechanical element (16) is a spring, a piston, a rubber element, or a magnet.
The lock mechanism (20, 30, 40) according to one of the claims 1 or 2, configured to cooperate with at least one identification key (21, 31) having an identification code (22, 32) and to switch from the locked state to the unlocked state if the identification code (22, 32) of the at least one identification key (21, 31) is an authorized code (23, 33) of the lock mechanism.
The lock mechanism (20, 30, 40) according to claim 3, comprising a processor (24, 34) configured to read the identification code (22, 32) of the at least one identification key (21, 31), determine if the identification code (22, 32) is an authorized code (23, 33) of the lock mechanism and deliver the switching command (12) if the identification code (22, 32) of the at least one identification key (21, 31) is an authorized code (23, 33) of the lock mechanism.
The lock mechanism (40) according to one of the claims 1 to 4, comprising a motor (41) configured to move the first abutment (14) between the disengaged position and the engaged position according to the switching command (12).
A locking system (50, 60, 70) comprising the lock mechanism (20, 30, 40) according to one of the claims 3 to 5 and the at least one identification key (21, 31), wherein the at least one identification key (21, 31) comprises a transmitter of the identification code (22, 32) and the lock mechanism comprises a receiver of the identification code (22, 32).
The locking system (50, 60, 70) according to claim 6, wherein the at least one identification key (21, 31) is an electronic key (21) or a remote control (31).
The locking system (60, 70) according to claim 6 or 7, wherein the at least one identification key (31) is a smart phone configured to receive the identification code (32) from an external connection or generate the identification code (32).
A method for preventing a lock mechanism submitted to vibrations from switching between a locked state and an unlocked state, the lock mechanism comprising:
- a lock clutch (11) configured to cause the lock mechanism to switch between a locked state and an unlocked state,

- a clutching mechanism (13) configured to be in an engaged position with the lock clutch (11) so as to cause the lock mechanism to switch between the locked state and the unlocked state, or in a disengaged position from the lock clutch (11) in the locked state,

- a mechanical element (16) configured to absorb the mechanical energy due to vibrations,
the method comprising a step (100) of absorbing by the mechanical element (16) the mechanical energy due to vibrations to which the lock mechanism is submitted in the disengaged position of the clutching mechanism (13) in the locked position and retracting, so as to prevent the clutching mechanism (13) from engaging with the lock clutch (11).
The method according to claim 9, the mechanical element (16) being a spring, wherein the step (100) of absorbing the vibrations comprises a step (101) of retracting the spring.