AU2023201258B1 - A lock mechanism - Google Patents

Abstract

A lock mechanism having a mechanical part, and an electronic part, wherein the electronic part controls a lock shielding member that is movable between an 5 access position and a secured position, the access position allowing a key to be inserted into the mechanical part, and the secured position preventing the key from being inserted into the mechanical part, and wherein the mechanical part is adapted to lock and unlock the lock mechanism. 10

Description

A LOCK MECHANISM

FIELD OF INVENTION The present invention relates to a lock mechanism. The present invention has particular but not exclusive application for a lock mechanism for a safe. The patent specification describes this use but it is by way of example only and the invention is not limited to this use.

BACKGROUND OF THE INVENTION Lock mechanisms for safes have been around for hundreds of years. Safes have a wide variety of appearances and types, almost all of the inner mechanical lock sets for safes are designed with disc locks and transmit movements by lugs. These locks have been effective at securing safes for many years, but they also have some drawbacks. One of the disadvantages of disc locks is that they can be interrogated and defeated relatively quickly by people who understand their working principles and characteristics. This means that anyone with knowledge of the lock's mechanisms can potentially gain access to the safe and its contents, making it less secure than it could be. In addition, some safe doors are designed with latches on one side and rely on hinges to remain secured on the other side. This can be a weakness, as the hinges can be exploited by someone trying to gain access to the safe. For instance, a person might be able to pry the door open by damaging the hinges, allowing them to bypass the lock entirely. There are a number of prior art solutions that try to address the shortcomings with doors and lock mechanisms for safes. Patent number US8555793B2 discloses a door structure which automatically activates an auxiliary lever when a hole is drilled in a specified area of the door. As a result, an intruder cannot continue to open the lock. However, the area of this certain protection zone is limited compared to the large area of the entire door. Patent US9238929B2 discloses a design of a safe door system which has a self-actuating mechanism sealing the remaining gaps between the door and the door frame when it is closed. This process helps prevent special tools being pushed along the gaps to crack the lock. When the safe is opened, a slot will automatically expand to the required position so that the door can be released from the frame. Patent US9359805B2 discloses linking a safe's locking pin to a fragile plate, both of which move on the same guideway. If there is an impact from the outside, this fragile plate will break and the locking pin will lose connection to the kinematic system of the safe. The fragile plate then inhibits the release of the locking pin and the lock cannot be opened. The idea is to introduce weak links into the locking pin drive chain so that it becomes the first element to be destroyed when the lock is broken, thus, creating an irreparable obstacle which inhibits further opening of the safe. Similar ideas are also found in many current designs of safes and doors. Traditional safe lock mechanisms have a few common vulnerabilities that can be exploited by attackers to gain unauthorized access to the safe. One such vulnerability is the noise that the lock mechanism makes during unlocking. By listening to the sounds produced by the lock mechanism, a skilled attacker can often determine the combination or pattern of movements required to unlock the safe. This is known as "safe cracking," and it can be done with minimal tools and a little bit of practice. Another vulnerability of traditional safe lock mechanisms is the load changes on the lock handle that occur after every movement. An attacker who understands the lock's workings can use the load changes to help them deduce the combination or pattern of movements required to unlock the safe. This type of attack is called "manipulation," and it can be very effective if the attacker has the necessary skills and experience. A third vulnerability of traditional safe lock mechanisms is the keyhole itself. This part of the lock is often a weak point that can be targeted by lock picking tools. With the right tools and techniques, an attacker can manipulate the lock mechanism directly through the keyhole, bypassing the need for the correct combination or pattern of movements entirely.

OBJECT OF THE INVENTION It is an object of the present invention to overcome or at least alleviate one or more of the above mentioned problems with lock mechanisms and/or provide the consumer with a useful or commercial choice.

SUMMARY OF THE INVENTION In one aspect, the present invention broadly resides in a lock mechanism having a mechanical part and an electronic part wherein the electronic part controls a lock shielding member, which is movable between an access position in which a key can be inserted into the mechanical part and a secured position in which the key is prevented from being inserted into the mechanical part and wherein the mechanical part is adapted to lock and unlock the lock mechanism. Preferably the electronic part includes a microcontroller adapted to cause the shielding member to move between the access position and secured position. Preferably the electronic part includes an actuator to move the shielding member between the access position and secured position. Preferably the actuator is a motor. In another embodiment, the actuator can be a linear motor, a pneumatic or hydraulic cylinder, a solenoid, a piezoelectric actuator and/or an electroactive polymer. Preferably the electronic part includes one or more electronic code input devices. Preferably the one or more electronic code input devices are adapted to send a signal to the microcontroller. Preferably on receipt of one or more correct signals, the microcontroller causes the shielding member to move to the access position. Preferably on receipt of a close signal, the microcontroller causes the shielding member to move to the secured position. Preferably the lock mechanism includes an input device which is adapted to send the close signal to the microcontroller. Preferably the input device is a button. Preferably the one or more electronic code input devices includes a mechanical combination mechanism. Preferably the mechanical combination mechanism is checked using an electronic sensor. Preferably the electronic sensor sends a signal to the microcontroller depending on the position of the combination mechanism. Preferably the electronic sensor is a non-contact electronic sensor. In one embodiment, the electronic sensor is a visual sensor. In one embodiment, the one or more electronic code input devices interact with the mechanical part of the lock mechanism. Preferably the one or more electronic code input devices interact with the mechanical part of the lock mechanism to prevent the key from unlocking the locking mechanism unless the one or more electronic code input devices are in a correct condition. In another embodiment the one or more electronic code input devices include a signal receiver. Preferably the signal receiver is adapted to receive a signal from a remote device. In one embodiment, the signal receiver is adapted to receive a signal from an nfc device, an rfid device, and/or a mobile device. In one embodiment, the one or more electronic code input devices include a fingerprint reader, biometric devices, facial recognition devices, voice recognition devices, iris recognition devices, keypad devices and/or the like. In one embodiment, the microcontroller requires a correct signal from each of a plurality of electronic code input devices to cause the shielding member to move to the access position. In one embodiment, the microcontroller requires a predetermined amount of time to elapse before it can receive a signal. In one embodiment, the microcontroller waits a predetermined amount of time after receiving a correct signal to move the lock shielding member. In one embodiment, the lock mechanism includes a transmitter. Preferably if an incorrect signal is received the transmitter is adapted to send a notification to a remote device. In another embodiment the transmitter is adapted to send a notification to a remote device and the remote device is adapted to send a signal to the signal receiver in response. Preferably the key is a mechanical key. In one embodiment, the key includes a signal device. In one embodiment, the key includes an nfc device, an rfid device and/or the like. In another embodiment, the key is a handle. Preferably the handle is rotatable attached to the lock mechanism. Preferably the handle is additionally movable in a linear direction in the direction of the axis of rotation. Preferably the lock mechanism includes a power source. In one embodiment, the lock mechanism is connectable to mains power. In another embodiment, the lock mechanism includes a battery. In one embodiment the lock mechanism includes an induction device to receive electrical power from a remote or portable source. Preferably the lock shielding member is a shielding disc. Preferably in the secured position, the lock shielding member separates the key from the mechanical part. More preferably in the secured position, the lock shielding member separates the key from a lock barrel in the mechanical part. Preferably unlocking of the lock barrel unlocks the lock mechanism. In one embodiment, the lock mechanism is associated with a door. Preferably the door has a left, right, top and bottom edge. Preferably the mechanical part includes one or more locking pins to secure the door in a frame in a locked condition. Preferably the mechanical part includes a plurality of locking pins to secure the door in a frame in a locked condition. Preferably each of the locking pins is associated with one of the left, right, top or bottom edge of the door. In one embodiment the lock mechanism includes a sensor to detect if the key is inserted and/or removed into/from the mechanical part. Preferably if the key is not detected being inserted into the mechanical part within a predetermined amount of time from the lock shielding member moving to the access position, the lock shielding member is moved to the secured position. Preferably when the key is detected being removed from the mechanical part, the lock shielding member is moved to the secured position. In a further aspect, the present invention broadly resides in a method of using a lock mechanism as described in this specification, including the steps of operating one or more electronic code devices to send one or more signals to the microcontroller; checking the one or more signals with the microcontroller and continuing if the one or more signals are correct; moving the lock shielding member to the access position; inserting the key into the mechanical part; and unlocking the lock mechanism with the key. Preferably the method further includes the step of locking the lock mechanism with the key. Preferably the method further includes the step of detecting when the key has been removed from the mechanical part. Preferably the method further includes the step of moving the lock shielding member to the secured position when the key has been removed from the mechanical part. In another aspect, the present invention broadly resides in a safe having a lock mechanism as described in this specification.

In a further aspect, the present invention broadly resides in a door having a lock mechanism as described in this specification. It will be appreciated that the lock mechanism may be referred to as a mechatronic lock mechanism. In one embodiment the lock mechanism is used to secure a door. Preferably the door is a safe door. The features described with respect to one aspect also apply where applicable to all other aspects of the invention. Furthermore, different combinations of described features are herein described and claimed even when not expressly stated.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the present invention can be more readily understood reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein: Figure 1 is perspective rear view of the lock mechanism according to an embodiment of the present invention; Figure 2 is a perspective view showing the vertical and front view of the lock mechanism; Figure 3 is a perspective view showing four modules A (door and the locking pins), B (key code input module), C (lock module), and D (drive module) separated from each other; Figure 4 is a perspective view showing module B in an assembled state; Figure 5 is an exploded view showing the details of module B; Figure 6 is a perspective view of module C; Figure 7 is a perspective view of the components of the lock module disassembled; Figure 8 is a perspective view showing module B and C; Figure 9 is a perspective view showing three different states of the lock mechanism including fully locked, partially locked, and fully unlocked; Figure 10 is a perspective view of module A disassembled; Figure 11 is a perspective view of module D; and Figure 12 is a diagram showing the working principle of the lock mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to Figures 1 to 11, there is shown a lock mechanism 100 in the form of a safe door according to a preferred embodiment of the present invention. The lock mechanism 100 includes module A which includes a door 133 and locking pins 34,35,36,37. The lock mechanism 100 includes module B which is a key code input module, which is part of the electronic part of the lock mechanism 100. The lock mechanism 100 includes module C which is the lock module, which is part of the mechanical part of the lock mechanism 100. The lock mechanism 100 includes module D which is the drive module. Figure 1 is a perspective showing a rear view of the lock mechanism 100. A rear metal protection plate (not shown) has been removed for clarity. Figure 2 is a perspective showing the front view of the door 133 and a part of the key code input module B which is attached through the door 133 and protrudes out. The code input module B includes a box 1 which also acts as a case to the component inside which will be explained in more detail below. The box 1 is secured to the door 133. A key 33 is mounted on the front side of the door and cannot be removed from the door. (in other embodiments which are not shown the key can be removed from the door) When a lock shielding disc 29 (best seen in Figure 7) is in a secured position, the key 33 also cannot be pushed into the lock module C, which means the key will rotate freely without being able to unlock the lock mechanism 100. Figure 3 is a perspective showing the four modules A, B, C, and D in a disassembled state. Figure 4 is a perspective showing a closer view of module B in an assembled state. Figure 5 is an exploded view showing the separated details of the disassembled module B. box 1 has holes 1A,1B,1C,1D to act as bearings carrying rotating shafts 4,8,15,11 on which the gears 3,6,13,10 are fitted in two pairs respectively. These gears 3,6,13,10 have the same number of teeth, usually 40 or 60. Disc 5 and disc 12 are engraved rims, which consist of 40 or 60 lines (not shown) that are equally spaced on the circumferences (depending on the number of teeth that the gears have). The engraved rim 5 and gear 6 are fixed to shaft 8, they are related to each other in terms of torque through pin 7. As a result, the combination of gear 6, engraved rim 5, shaft 8, and pin 7 always spin together. Similarly, the engraved rim 12, gear 13, shaft 15, and pin 14 have the same mounting way. However, gear 6 only engages gear 3, and gear 13 only engages gear 10. Bearing 2 has a hexagonal hole cutout (if the gear has 60 teeth and a square hole if the gear has 40 teeth) tightly fitted with gear 3. This bearing will rotate on the hole of case 1 when gear 3 receives a transmission from gear 6. Similarly, gear 10 rotates on shaft 9 when receiving drive motion from gear 13. Thus, two independent kinematic chains are formed. The first kinematic chain starts with the moment from the engraved rim 5 which rotates gear 6. Following this, the moment is then transmitted to gear 3 which rotates the hexagonal shaft 4. Finally, the moment transmits to the lock module. The second kinematic chain starts with the moment from the engraved rim 12 which rotates gear 13. Following this, the moment then transmits to gear 10 and the hexagonal shaft number 11. In the end, the moment transmits to the lock module. The two engraved rims 5 and 12 receive the moment from the hands of users in the unlocking process. The key code input module B only has the function of receiving the key code from two kinematic chains and transmit to the lock module. The verification of this key code is the responsibility of the lock module, which also has the function of helping users switch to a new key code by temporarily cutting off the internal link of the kinematic chains and changing the old absolute position of the links in those chains. After re-establish the chains, the key code will finally be changed to the new one. The key code modification process does not require removing modules A, B, C, and D from their mounting positions. Figure 6 is a perspective showing the complete assembled state of the lock module C. Figure 7 is an exploded view of the lock module C. The centre disc 24 has two rectangular holes symmetrical about the centre which are tightly fitted to centre shaft 26. This centre shaft acts as the rotation axis of the centre disc 24 on lock case 16. Both of the two satellite discs 23 and 20 only have rectangular holes fitted with shafts 22 and 21 respectively. These shafts 21,22 act as rotation axes for the satellite discs 20,23 in the body of lock case 16. Optical discs 19 and reader 18 allow determining the location of two satellites discs 23 and 20. The optical disc 19 is assembled to the end of shaft 21 by a suitable construction so that they rotate together. During the movement, optical disc 19 does not have physical contact with reader 18. As a result, there is not any force that appears at this stage when the lock is working. This characteristic is necessary to avoid force detection in order to determine whether the lock is in an open or closed condition. The lock is said to be open if shaft 26 can receive torque from key 33 and rotates around its shaft in two directions, otherwise, it is half-locked if it can receive torque from key 33 but cannot turn. Finally, if the lock shielding disc 29 prevents key 33 from entering lock shaft 26, the lock is completely locked. In Figure 7, mount 27 mounts motor 28 to the body of case 16 as a fulcrum for lock shielding disc 29 to rotate on the motor 28. The lock shielding disc 29 enables the square key 33 to engage with the lock on shaft 26 in an access position and to prevent this process by moving to a secured position facing the end of shaft 26 or to the side. These two positions of the lock shielding disc 29 are confirmed by two limit switches 17 which are mounted on case 16. The motor 28 stops moving when the limit switches 17 are physically contacted. Figure 7 shows bearing 30 containing a push spring 31 and the key 33 inside, which is compressed into the right position by pin 32 to prevent the spring from pushing the key 33 out of the lock and keeping it in a separated state from the lock hole in shaft 26. Then when the key rotates freely, it is blocked in front by the lock shielding disc 29, so the spring cannot push key 33 into the lock to unlock. Figure 8 is a perspective showing the kinematic and structural linkage between the key code input module B and the lock module C. Four different kinematic chains will be introduced below: The first chain is the left encoder branch which includes engraved rim 5, shaft 8, gear 6, gear 3, bearing 3, gear 2, prismatic hexagonal shaft 4, bearing 22, satellite gear 23. This chain is monitored by the optical disc 19 and its independent reader 18. The second chain is the right branch which includes engraved rim 12, shaft 15, gear 13, gear 10, bearing 9, prismatic hexagonal shaft 11, bearing 21, satellite gear 20. This chain is monitored by a corresponding one of the optical discs 19 and its independent reader 18. The third chain is the one that closes or opens the key starting from key 33 to lock 26, this chain has a natural limitation which is the dead points of the partially rotated four-bar hinge mechanism.

The fourth chain is the one that opens or closes the lock shielding disc 29 starting from the motor 28 to the lock shielding disc 29. This chain is monitored by two limit switches 11. Thus, while the key code input module and the lock module are both structurally mounted on the door of the safe, in terms of kinematics they are linked by two prismatic hexagonal shafts (4 and 11). These two shafts only locate in the hexagonal holes of the bearings 21,22,2,9 without clamping them at all. This state allows to both transmit torque precisely and these shafts can still be lifted to be reassembled easily without the need to use any tools when the inter-link between the key code input module and the lock module needs to be cut. Figure 9 is a perspective view showing how the different states of the lock set are determined by the angular position of the three vacant wheels. In the top picture, the full solid part of satellite wheels 23 and 20 rims are in the missing part of the centre wheel 24 locking wheel 24. Since the wheel 24 cannot rotate, the key 33 also cannot turn. In this situation, both satellite wheels 23 and 20 contribute to hindering the rotation around the shaft of the centre wheel 24. In the centre picture of Figure 9, the missing position of satellite wheel 20 is located in the same place as the missing position of centre wheel 24, therefore, it does not hinder the rotation of wheel 24. However, as wheel 23 is hindering the rotation of wheel 24, this is a one-sided locking situation of the lock set. In the bottom picture of Figure 9, both satellite wheels 23 and 20 have the missing position at the intersection point with the missing position of centre wheel 24. Since this state enables centre wheel 24 to rotate freely around its shaft, this is the unlocked state. If both engraved rims 5 and 12 have 60 engraved lines evenly spaced on the circumference, the gears 3/6 and 13/10 will all have 60 teeth each. The probability of correctly detecting the key code of the mechanical part of the key is 1/ 3600, which is the probability for the mechanical part alone, not to mention the electronic part. On the other hand, the mechanical code can be changed if required. Figure 10 shows that the locking pins on one side are rigidly welded to a V shaped steel bar (bars 34, 35, 36, and 37) at the required distance. There is a hole on this V-bar drilled for connecting these pins with parallel bars 39, 41, and 43 (Figure 11). On door 133, suitable steel plates are welded together to create a door box and holes are drilled for the pins to pass through. These holes have two important functions, the first one is to be the correct guidance for the movement of the pins 34,35,36,37, and the second function is to hold the door 133 firmly to a door frame (not shown) in case it is necessary to resist external mechanical impacts. The requirement with the pins 34,35,36,37 is that although during centripetal movement they will come closer to each other, at the end of the motion cycle, they must not collide with each other. All locking pins 34,35,36,37 are arranged in a co-planar in order to use the simplest structure and technology for making locks and doors. In Figure 11, the centre disc 38 is mounted on the centre shaft 26. One end of each transmission rods 39,41,43 is connected to the centre disc by pins 42 and the other end of the transmission rods 39,41,43 is connected to the door latches (pins 34,35,36,37) by pins 40. This system forms four four-bar hinge mechanisms which convert the circular motion of the centre disc 38 into a reciprocating motion of the pins through the parallel motion of the transmission rods 39/41/43. In order to reverse the reciprocating motion of the pin, the rotation of disc 38 is reversed by key 33. With reference to Figure 12 there is shown a simplified diagram showing the operation of the lock mechanism 200 of an embodiment of the present invention. The lock mechanism 200 uses several control components including a microcontroller 210, position sensors 212, and secondary limit switches (not shown). The actuator system includes the shielding disc 29 and motor 28. The microcontroller 210 requires a correct signal from both the signal receiver 214 and the position sensors 212. The signal receiver receives a signal from an electronic key code input device 216 (such as an NFC tag). The position sensor 212 receive an input from the mechanical key code input module 218, which also interacts with the lock module 220. On receipt of correct signals from both the signal receiver 214 and the position sensor 212, the microcontroller 210 controls the motor 28 to move the locking shield disc 29 to an access position such that key 33 can be inserted into lock 26 and the locking mechanism can be unlocked by key 33. Figure 12 shows that there are two routes to provide power and information to the active part, motor 28. These two routes form the necessary and sufficient conditions which are independent of each other, however, they still have internal information integration. The information is initialized by the optical sensor (non contact position sensor). The necessary condition to rotate the lock shielding disc is to rotate to the correct mechanical code installed on the two engraved rims 5 and 12, as this action will supply power to motor 28. The sufficient condition to rotate the lock shielding disc 29 out of the position which blocks the way to the lock is a correct electronic signal (use one of the electronic code input methods such as RFID, fingerprint, keyboard, remote, ... ). In order to increase safety, when the locking pins close, the user will lock the centre shaft 26. When this shaft cannot rotate, there is no way to pull the locking pins out of the door frame, and the door cannot be opened. This is the central locking and transmission mechanism which means that only one link (shaft 26) drives all the locking pins and when shaft 26 is locked, no locking pins are able to move. The necessary condition to rotate shaft 26 is to put the key in the lock, in order to do this, it is necessary to rotate the two engraved rims 5 and 12 to the correct code position. Once the code is correct, reader 18 will confirm the correct position and transmit the position signal to the microcontroller so as to power the electric motor 28. On the other hand, the sufficient condition is opening the lock shielding disc 29 using one of the additional verification methods such as RFID card/ remote/ phone message/ fingerprint/ numeric keypad, and many other ways to control the electric motor. Following this, the code is turned to adjust the satellite wheels 20 and 23 to the state of releasing the centre wheel 24 completely. After that, the centre shaft 26 can be rotated to pull the locking pins in and release the door. The components constituting the kinematic chains need to have a suitable mechanical gap so that the accumulated looseness of the whole chain is minimized. This ensures the accuracy of the two satellite wheels' position. If the looseness is too large, the satellite wheel position can just be in the vicinity of the correct position but not completely correct, therefore, the lock is still unable to be opened even if the key code is right. The lock shielding disc 29 is moved to the access position by motor 28 of which operation depends on the authorized control command. The authorized control command can be a command sent from an authorized device, a command associated with security information, a command associated with an authorized user's biometric information, or a combination of them. The authorized device can be an RFID tag with a unique identifier, which is one of the identifiers allowed to open the hood, a remote handheld device, or something similar. An authorized person's biometric information can be fingerprint, face, iris, or something similar. Therefore, unlocking the lock details and unlocking the lock shielding disc can be done through fingerprint scanning of an authorized person, entering a password memorized/stored by an authorized person, using an RFID card having a valid unique identifier, using a separate handheld remote control for each device, send commands over the mobile network from the authorized person's phone, send commands over the internet from an authorized person, or similar methods. An authorized control command could also be sent through an authorized person's mobile app. A mobile device such as a smartphone is usually unlocked with biometric information, so this method can ensure safety while being convenient for users. Description of the lock operation: Initially, the system is in the locked state and the door 133 is closed. The mechanical lock is assumed to be in a random state, while key 33 is not able to enter the lock in the centre shaft 26 because the lock shielding disc 29 is located between key 33 and the lock in the centre shaft 26 (Figure 8). After the two engraved rims 5 and 12 are rotated to the correct pre-defined code position, the two readers 18 confirm the position of the mechanical lock. Once both satellite wheels 20 and 23 are in place which allows the centre wheel 24 to rotate freely, the signal from the microcontroller gives permission for motor 28 to be energized. In this stage, motor 28 already has power but still misses the control signal, therefore, users need to continue entering the electronic key code by one of the methods such as fingerprint, RFID card, phone message, or numeric keypad to confirm ownership. Following this, the lock shielding disc 29 is moved to the access position. The user pushes key 33 axially to engage the lock in the centre shaft 29. After that, the user rotates the key to turn shaft 26 counterclockwise in order to pull the pins 34,35,36,37 into the centre of the door 133. Finally, the door is released to its free state. When the centre wheel has rotated, the satellite wheels in the lock are kept stationary and cannot rotate, this is necessary since when the safe is locked, the user can immediately turn the centre wheel without having to find the code again. On the other hand, this means that if the correct mechanical code is not entered for the engraved rims, motor 28 (Figure 8) has no power, and key 33 cannot be inserted into the lock in centre shaft 26. Therefore, no one can mechanically affect the lock set to open and verify the predicted code. The process of trying will take time and there is no way to conclude to conclude whether the code is right or wrong, not to mention that if the lock is to be fully unlocked, an electronic code input method (RFID card, phone with defined sim, remote, etc.) is required. Key 33 can also never be forgotten in the lock since it is compressed into the lock, and spring 31 (Figure 7) will automatically pop the key out when let go. However, because blocking pin 32 (Figure 7) does not allow it to be separated from bearing 30, the key 33 barely moves out of the lock so that the lock shielding disc 29 can move to the secured position, and cannot be fully removed from the lock. This is another advantage as a universal tool to probe the lock through the keyhole cannot be used as the key 33 is in the way. In order to lock the door 133, firstly the door 133 is closed relative to a frame (not shown), the key 33 is compressed into the lock into shaft 26 and turned clockwise to push the locking pins 34,35,36,37 away from the centre of the door 133 and secure them relative to the frame. When the key 33 stops turning and is let go, it automatically pops out of the lock in shaft 26. Subsequently, a user uses a remote, RFID card, or numeric keypad to close the lock shielding disc 29. It should be noted that regardless of the accuracy of the mechanical code, it is always possible to close the lock shielding disc at this stage. However, users are required to input the correct mechanical code once they want to open it. This is the cross-link check mutual binding in the mechatronic system's command execution through the information provided by the optical and position sensors. When the lock shielding disc is in operation, the limits of these components are determined by two limit switches 17. These switches send signals to the microcontroller to turn on or off the power supply of motor 28. If a user wants to change the mechanical code, they have to access the lock by removing the cover on the back of the door (as seen in Figure 1). The kinetic transmission between the key code input module and the lock module is performed by two prismatic hexagonal shafts 4 and 11 (Figure 8). These two shafts are mounted in two prismatic hexagonal inner surfaces of the bearings named pairs 2,22 and 9,21, respectively. With the intention of changing the code, users just need to lift the shafts vertically to break the kinematic link of the chain. For instance, firstly, prismatic hexagonal shaft 4 can be lifted in a way that makes it exit completely from the prismatic hexagonal hole in bearing 22 but still fit in bearing 2. After that, the code entry ring 5 should be rotated by an angle which equals the divisor of 60 (60 is the number of gear teeth in the lock set), then users drop the hexagonal shaft 4 back down into the hexagonal hole of the bearing 22. The code on the right side can be changed in a similar manner. During the code-changing process, users only have to open the cover behind the door without using any mechanical tools, thus the code can be changed quickly and simply. The reason why the prismatic hexagonal shaft must be rotate to an angle equal to the divisor of 60 is that it will enable the prismatic hexagonal shaft to be reinstalled into the prismatic hole on bearing number 2 or 21. As this shaft has 6 sides, so only when we rotated the shaft multiple times or a divisor of 6, can the interlink between the key code input module and the lock module be re-formulated. This is the basic principle in the dynamic linkage of mechanical transmission. On the other hand, the process of changing the electronic code depends on the code input method selected specifically for the safe. Module A may also optionally contain an unlock motor's 28 power supply circuit. This power supply circuit is used to activate the unlock motor 28 operation based on authorized control commands. When an authorized control command is not received, the power supply circuit will not provide energy to the unlock motor 28. In this way, even if someone can somehow gain access to module A and the electrical wires/signal wires which connect from the control cabinet or external power sources to the unlock motor 28, the motor 28 will not work. The provision of power is just the necessary condition, in order to activate the motor, we still have to satisfy the sufficient condition by generating a control signal similar to the authorized control signal. The lock mechanism of this invention can be powered by either a primary source of energy (such as mains power) or a backup source (such as a battery) or via an external source (such as inductive power).

ADVANTAGES An advantage of the preferred embodiment of the lock mechanism includes that it can be applied to heavy-duty safe doors, hatches, and solid structures that require a high level of security and protection.. Another advantage of the preferred embodiment of the lock mechanism includes the combination of mechanical and electronic parts provides a robust and reliable means of securing the contents of a safe or other secured area. A further advantage of the preferred embodiment of the lock mechanism includes that the movable lock shielding member provides an additional layer of protection for the lock mechanism itself, by preventing access to the mechanical part of the lock when it is in the secured position, the lock shielding member ensures that the lock cannot be tampered with or bypassed.

VARIATIONS While the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth. Throughout the description and claims of this specification the word "comprise" and variations of that word such as "comprises" and "comprising", are not intended to exclude other additives, components, integers or steps.

Claims (20)

1. A lock mechanism having: a mechanical part; and an electronic part, wherein the electronic part controls a lock shielding member that is movable between an access position and a secured position, the access position allowing a key to be inserted into the mechanical part, and the secured position preventing the key from being inserted into the mechanical part, and wherein the mechanical part is adapted to lock and unlock the lock mechanism; and wherein the lock mechanism includes a centre wheel and at least two independent kinematic chains, each kinematic chain having at least one satellite gear configured to hinder the rotation of the centre wheel, when the centre wheel is hindered by any satellite gear the mechanical part is in a locked state.

2. A lock mechanism as claimed in claim 1 wherein the electronic part includes a microcontroller adapted to move the shielding member between the access position and the secured position.

3. A lock mechanism as claimed in claim 2 wherein the electronic part further includes an actuator to move the shielding member.

4. A lock mechanism as claimed in claim 3 wherein the microcontroller is adapted to control the actuator.

5. A lock mechanism as claimed in claim 3 or 4, wherein the actuator is a motor.

6. A lock mechanism as claimed in any one of claims 2 to 5, wherein the electronic part includes one or more electronic code input devices adapted to send a signal to the microcontroller.

7. A lock mechanism as claimed in claim 6 wherein the microcontroller moves the shielding member to the access position upon receiving one or more correct signals from the one or more electronic code input devices.

8. A lock mechanism as claimed in any one of claims 2 to 7, wherein the microcontroller moves the shielding member to the secured position on receipt of a close signal.

9. A lock mechanism as claimed in claim 8 wherein the lock mechanism includes an input device which is adapted to send the close signal to the microcontroller.

10. A lock mechanism as claimed in claim 6 or 7 wherein the one or more electronic code input devices include a mechanical combination mechanism.

11. A lock mechanism as claimed in claim 10 wherein the mechanical combination mechanism is checked using an electronic sensor, and the electronic sensor sends a signal to the microcontroller depending on the position of the combination mechanism.

12. A lock mechanism as claimed in claim 11 wherein the electronic sensor is a non-contact electronic sensor.

13. A lock mechanism as claimed in any one of claims 10 to 12 wherein the one or more electronic code input devices interact with the mechanical part of the lock mechanism to prevent the key from unlocking the locking mechanism unless the one or more electronic code input devices are in a correct condition.

14. A lock mechanism as claimed in any one of the preceding claims when dependent on claim 6 further including a transmitter adapted to send a notification to a remote device if an incorrect signal is received.

15. A method of using a lock mechanism as claimed in any one of the preceding claims when dependent on claim 6, the method including the steps of: operating one or more electronic code devices to send one or more signals to the microcontroller; checking the one or more signals with the microcontroller and continuing if the one or more signals are correct; moving the lock shielding member to the access position; inserting the key into the mechanical part; and unlocking the lock mechanism with the key.

16. A method as claimed in claim 15, further including the step of locking the lock mechanism with the key.

17. A method as claimed in claim 15 or claim 16 further including the step of detecting when the key has been removed from the mechanical part.

18. A method as claimed in claim 17 further including the step of moving the lock shielding member to the secured position when the key has been removed from the mechanical part.

19. A door having a lock mechanism as claimed in any one of claims 1 to 14.

20. A safe having a lock mechanism as claimed in any one of claims 1 to 14.