Magnetic induction automatic lock

Abstract

The invention discloses a magnetic induction automatic lock which comprises a lock body and a floating lock rod seat. A lock hook and a magnetic field induction device are arranged on the side, close to the floating lock rod base, of the lock body. A permanent magnet and a lock rod are fixedly connected to the side, close to the lock body, of the floating lock rod base. The permanent magnet and the lock rod respectively correspond to the magnetic field induction device and the lock hook; the floating lock rod seat is fixed at the bottom end of the drawer and synchronously floats along with the drawer; the lock body is arranged in the cabinet body corresponding to the drawer; the locking state does not depend on continuous power maintenance, is still firm after power failure, and is safe and reliable.

Description

Technical Field

[0001] This invention belongs to the field of smart locks. Background Technology

[0002] Currently, there are two main technical approaches for automatic locking devices used in office drawers, each with its own obvious limitations:

[0003] Purely mechanical trigger locks rely on the mechanical impact when the drawer is closed to directly drive the bolt action and achieve locking. While simple in structure, they have significant drawbacks: after prolonged use, the mechanical parts are prone to wear or fatigue, leading to decreased locking force, inaccurate positioning, and even unpleasant noise; furthermore, the locking and unlocking process depends entirely on the user's pushing force, making intelligent status sensing and electronic control linkage impossible.

[0004] Electromagnetic locks typically use the energization and de-energization of electromagnets to control the bolt. Their advantage is that they can be electrically controlled. However, their disadvantages are equally significant: to maintain the locked state, the electromagnet usually needs continuous power, resulting in high energy consumption; in the event of a power outage, the lock may completely fail or be unable to accurately detect the locked / unlocked status, posing a security risk. Furthermore, their structure requires high manufacturing precision and power supply stability. Summary of the Invention

[0005] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a magnetic induction automatic lock that achieves the locking state without relying on continuous power, and remains secure even after power failure, making it safe and reliable.

[0006] Technical Solution: To achieve the above objectives, the present invention provides a magnetic induction automatic lock, comprising a lock body and a floating lock bar seat; a lock hook and a magnetic field sensing device are provided on the side of the lock body near the floating lock bar seat, and a permanent magnet and a lock bar are fixedly connected to the side of the floating lock bar seat near the lock body; the permanent magnet and the lock bar correspond to the magnetic field sensing device and the lock hook, respectively; the floating lock bar seat is fixed to the bottom of the drawer and floats synchronously with the drawer; the lock body is located in the cabinet corresponding to the drawer.

[0007] When the drawer is pushed all the way down, the permanent magnet and the magnetic field sensing device are in a position close to each other. The magnetic field strength sensed by the magnetic field sensing device just exceeds the preset threshold. At the same time, the lock hook can swing under the drive of the transmission device in the lock body to hook the lock bar.

[0008] Furthermore, the lock body includes a lock shell, the root of the lock hook is connected to the swing arm, and a swing shaft is fixedly connected to the end of the swing arm away from the lock hook, with the swing shaft rotatably mounted on the lock shell.

[0009] Furthermore, a drive motor is fixedly installed inside the lock housing, and the output end of the drive motor drives a worm gear. A worm wheel that cooperates with the worm gear is provided inside the lock housing, and the worm wheel cooperates with the swing shaft through a gear transmission chain inside the lock housing.

[0010] Furthermore, the lock housing is provided with a limiting inclined wall and a limiting edge;

[0011] When the locking hook is in the "hooked" position, the side of the swing arm away from the limiting inclined wall is in limiting contact with the limiting edge;

[0012] When the locking hook is in the "released" position, the side of the swing arm away from the limiting edge makes contact with the limiting inclined wall.

[0013] Furthermore, the inner side of the lock hook has an inner arc surface; when the lock hook is in the "hooked" position, the inner arc surface slides tangentially to the lock bar or there is a gap; the center of the inner arc surface coincides with the axis of the swing shaft.

[0014] Furthermore, the end of the locking hook is fixedly connected to the end of the swing arm.

[0015] Furthermore, the tail end of the lock hook is hinged to the end of the swing arm; a wire reel compartment is provided inside the lock housing, and a wire reel is provided inside the wire reel compartment. A wire groove is arranged around the outer ring of the wire reel, and the inner ring of the wire reel is rotatably mounted on the wire reel shaft through a bearing; a traction wire passage is provided on the part of the swing arm near the hinge, and a wire-passing groove that overlaps with the traction wire passage is hollowed out on the limiting inclined wall; it also includes a traction wire made of high-strength metal fiber or other fiber, which passes through the traction wire passage and the wire-passing groove; one end of the traction wire is fixedly connected to the wire groove of the wire reel, and the other end is fixedly connected to the tail end of the lock hook;

[0016] It also includes a torsion spring that applies clockwise torque to the reel. Under the pull of the traction line, the locking hook swings down around the hinge to the lower position to abut against the swing arm, forming a fitting seam at the abutment. When the swing arm swings to the limit engagement limit edge and the locking hook is in the "hooked" state, the traction line is completely released by the reel, and the extension line of the traction line passes through the center of the reel.

[0017] The end of the lock hook is provided with a section of inclined surface that connects to the inner arc surface at an obtuse angle. When the lock hook swings with the swing arm and the inclined surface comes into contact with the lock bar, the force F1 exerted by the lock bar on the inclined surface causes the lock hook to tend to rotate counterclockwise around the hinge.

[0018] Furthermore, the torque provided by the torsion spring, when converted into tension in the traction cable, does not significantly counteract or promote the swing of the arm.

[0019] Furthermore, when the user pushes the drawer all the way down, the magnetic field strength sensed by the magnetic field sensor just exceeds the preset threshold; the controller controls the drive motor, so that the worm gear drives the swing shaft through the gear transmission chain in the lock case, so that the swing arm with the lock hook rotates clockwise around the axis of the swing shaft; the swing arm with the lock hook rotates clockwise around the axis of the swing shaft until the side of the swing arm away from the limit inclined wall contacts the limit edge; when unlocking is required, the user unlocks via NFC, and the controller controls the worm to reverse.

[0020] Beneficial effects: This invention uses a non-contact permanent magnet and a magnetic field sensor as the triggering unit. The sensor only senses a sufficiently strong magnetic field and triggers a signal when the drawer is fully closed, achieving near-zero wear, long lifespan, and accurate state sensing with extremely low power consumption.

[0021] The locking actuator employs a purely mechanical method using a motor-driven worm gear and gear transmission. The worm gear mechanism possesses a reverse self-locking characteristic; once locked in place, even under external tension, the locking hook cannot disengage on its own. The locked state does not rely on continuous power; it remains secure even after power is cut off, ensuring safety and reliability.

[0022] The center of the inner arc surface of the locking hook is designed to coincide with the rotation axis of the swing arm. This ensures that when an external pulling force is applied to the inner arc surface of the locking hook in the locked state, the direction of the force passes through the center of rotation, resulting in zero torque. This design eliminates the reverse load of the pulling force on the transmission system in the locked state, greatly enhancing the mechanical stability of the locking mechanism, avoiding shaking noise, and significantly extending the lifespan of the transmission components.

[0023] The second embodiment employs an adaptive correction and locking mechanism to address springback errors.

[0024] To address the problem of slight rebound after the drawer is closed, which may cause the locking lever to shift position, this invention proposes an ingenious hinge-traction line-coil flexible adaptive subsystem.

[0025] When the locking hook interferes with the offset locking bar, the locking hook can rotate adaptively around the hinge, turning the collision into guidance, allowing the locking bar to slide smoothly into the inner arc surface.

[0026] More importantly, during the subsequent swinging process, the fixed-length traction line and the swing arm working together will force the lock hook to rotate and apply a corrective force F2 to the lock rod to "push" it back to the correct position, thus actively correcting the drawer position.

[0027] Finally, upon successful locking, the traction line returns to a rigid connection, ensuring the stability of the locking hook. This mechanism represents a leap from "passive collision" to "active guidance and correction," significantly improving the success rate of locking and the user experience. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the first embodiment;

[0029] Figure 2 This is a schematic diagram showing the unlocked and locked states of the first embodiment;

[0030] Figure 3 This is a schematic diagram of the first embodiment where the end of the locking hook directly contacts the locking bar, causing motion interference.

[0031] Figure 4 A schematic diagram of the transmission structure inside the lock body;

[0032] Figure 5 This is a schematic diagram of the structure of the second embodiment;

[0033] Figure 6 This is a cross-sectional view of the second embodiment;

[0034] Figure 7 This is a schematic diagram of the locking process in the second embodiment. Detailed Implementation

[0035] The invention will now be further described with reference to the accompanying drawings.

[0036] like Figures 1 to 7 The magnetic induction automatic lock shown includes a lock body 71 and a floating lock bar seat 4; a lock hook 2 and a magnetic field sensing device 11 are provided on the side of the lock body 71 near the floating lock bar seat 4; a permanent magnet 6 and a lock bar 3 are fixedly connected to the side of the floating lock bar seat 4 near the lock body 71; the permanent magnet 6 and the lock bar 3 correspond to the magnetic field sensing device 11 and the lock hook 2 respectively; the floating lock bar seat 4 is fixed to the bottom of the drawer and floats synchronously with the drawer; the lock body 71 is installed in the cabinet corresponding to the drawer; drawer slides are provided on both sides of the drawer.

[0037] When the drawer is pushed all the way down, the permanent magnet 6 and the magnetic field sensing device 11 are in their closest position, and the magnetic field strength sensed by the magnetic field sensing device 11 just exceeds a preset threshold. At the same time, the locking hook 2 can swing under the drive of the transmission device in the lock body 71 to hook the locking bar 3. The magnetic field sensing device 11 is preferably a Hall sensor, and its preset threshold is precisely set according to the magnetic field strength of the selected permanent magnet 6 and the installation distance, for example, it can be set to 30mT. Its working principle is as follows: when the drawer is not closed all the way down, the magnetic field strength sensed by the sensor is lower than the threshold, and the controller does not issue a locking command; when the drawer is pushed all the way down, the distance between the permanent magnet 6 and the sensor is shortened to the design value, such as 3-5mm, the magnetic field strength exceeds the threshold, the sensor outputs a signal to the controller, triggering the subsequent locking action.

[0038] The lock body 71 includes a lock shell 1, the root of the lock hook 2 is connected to the swing arm 5, and the end of the swing arm 5 away from the lock hook 2 is fixedly connected to the swing shaft 12, which is rotatably mounted on the lock shell 1.

[0039] A drive motor 15 is fixedly installed inside the lock housing 1. The output end of the drive motor 15 drives a worm gear 8. A worm wheel 14, which meshes with the worm gear 8, is provided inside the lock housing 1. The worm wheel 14 drives the swing shaft 12 through a gear transmission chain 13 inside the lock housing 1. The gear transmission chain 13 is composed of several meshing gear sets. The gear transmission chain 13 amplifies the torque of the worm wheel 14 and transmits it to the swing shaft 12, thereby driving the swing shaft 12 to rotate, thus causing the swing arm 5 to rotate around the axis of the swing shaft 12. The drive motor 15 is a miniature DC geared motor, and the operating voltage can be 5V or 12V. The worm gear 8 and the worm wheel 14 constitute the first-stage reduction and self-locking mechanism, and their transmission ratio can be designed as needed, for example, 10:1. The gear transmission chain 13, as the second-stage transmission, can be composed of two or more pairs of steel or engineering plastic gears, further amplifying the torque and reducing the speed to a range suitable for the swing arm 5 to swing. After receiving the controller command, the motor rotates forward and transmits power to the swing shaft 12 through multi-stage reduction, driving the swing arm 5 and the locking hook 2 to swing slowly and powerfully to the "hook" position. Since the worm gear mechanism has a reverse self-locking characteristic, that is, the worm can only drive the worm wheel, and the worm cannot rotate otherwise, after locking in place, even if the locking rod 3 is subjected to outward pulling force, it cannot drive the transmission system in the reverse direction, thus achieving reliable mechanical self-locking.

[0040] The lock housing 1 is provided with a limiting inclined wall 9 and a limiting edge 10; when the lock hook 2 is in the "hooked" position, the side of the swing arm 5 away from the limiting inclined wall 9 makes limiting contact with the limiting edge 10; when the lock hook 2 is in the "released" position, the side of the swing arm 5 away from the limiting edge 10 makes limiting contact with the limiting inclined wall 9.

[0041] The inner side of the locking hook 2 has an inner arc surface 7. When the locking hook 2 is in the "hooked" position, the inner arc surface 7 slides tangentially with the locking rod 3 or has only a slight gap. This prevents the drawer from bouncing back and forth under external pulling force when locked, improving the perceived quality. The center of the inner arc surface 7 coincides with the axis of the swing shaft 12. This ensures that when the drawer is locked and under external pulling force, the pulling force of the locking rod 3 on the locking hook 2 will not be converted into torque on the swing shaft 12, thus reducing the burden on the transmission structure. The coincidence of its center with the axis of the swing shaft 12 is a design feature of this invention. When the locking hook 2 hooks the locking rod 3 and is subjected to outward pulling force, this pulling force is always along the radial direction of the inner arc surface 7, i.e., pointing towards the axis of the swing shaft 12. Since the line of action of the force passes through the center of rotation, the torque generated by this pulling force is zero, and therefore will not attempt to drive the swing arm 5 and the entire transmission chain to reverse. This makes the locked state stable, and all tension is directly borne by the bearings of the lock housing 1 and the swing shaft 12, which greatly reduces the load on the worm gear and gears and improves the long-term reliability of the transmission system.

[0042] First embodiment:

[0043] like Figures 1 to 3As shown, the tail end of the locking hook 2 is fixedly connected to the end of the swing arm 5. Ideally, if the user pushes the drawer all the way down, the locking rod 3 moves horizontally with the drawer and the floating locking rod seat 4 to the predetermined position. If the drawer does not spring back, the locking hook 2 can smoothly move with the swing arm 5 to just "hook" the locking rod 3. However, in some unexpected situations, such as after the locking rod 3 moves horizontally with the drawer and the floating locking rod seat 4 to the predetermined position, the drawer slightly springs back due to inertia and collisions. After the locking rod 3 stabilizes, it slightly deviates from the predetermined position. Subsequently, during the process of the locking hook 2 moving with the swing arm 5 to the "hooking" position, it may not be able to smoothly hook the locking rod 3; instead, the end of the locking hook 2 directly touches the locking rod 3, causing motion interference. Figure 3 As shown, this may indicate a decoupling issue. To address this problem, the following optimization scheme was designed.

[0044] Second embodiment:

[0045] like Figure 5 , 6 As shown in Figure 7, the tail end of the lock hook 2 is hinged to the end of the swing arm 5 via a hinge 16; a wire reel compartment 65 is provided inside the lock housing 1, and a wire reel 21 is provided inside the wire reel compartment 65. A wire groove is formed around the outer ring of the wire reel 21, and the inner ring of the wire reel 21 is rotatably mounted on the wire reel shaft 20 via a bearing; a traction wire passage 17 is provided on the part of the swing arm 5 near the hinge 16, and a wire threading groove 19 is hollowed out on the limiting inclined wall 9, which overlaps with the traction wire passage 17; it also includes a traction wire 18 made of high-strength metal fiber or other high-strength fiber, which passes through the traction wire passage 17 and the wire threading groove 19; one end of the traction wire 18 is fixedly connected to the wire groove of the wire reel 21, and the other end is fixedly connected to the lock The hook 2 also includes a torsion spring that applies a clockwise torque to the reel 21. The torsion spring in this design provides a relatively small torque, which translates into a small tension in the traction line 18 and will not significantly counteract or promote the swing of the swing arm 5. The torque of the torsion spring is carefully calculated, for example, set to 5 mN·m, which is sufficient to wind up the slack traction line 18, but is significantly less than the torque exerted on the swing arm 5 by the drive motor 15 through the transmission system. In this design, the main function of the torsion spring is that when the traction line 18 becomes slack, the traction line 18 will be wound into the groove outside the reel 21 under the torque provided by the torsion spring, maintaining the relative tension and appropriate tension of the traction line 18.

[0046] Under the pull of the traction line 18, the locking hook 2 swings downward around the hinge 16 until it is in the lower position and closes to the swing arm 5, forming a fitting seam 28 at the contact point; when the swing arm 5 swings to the limit engagement limit edge 10 and the locking hook 2 is in the "hooked" state, the traction line 18 is completely released by the spool 21, and the extension line of the traction line 18 passes through the center of the spool 21.

[0047] The end of the locking hook 2 is provided with a section of inclined surface 29 that connects to the inner arc surface 7 at an obtuse angle. When the locking hook 2 swings with the swing arm 5 and the inclined surface 29 comes into contact with the locking rod 3, the force F1 exerted by the locking rod 3 on the inclined surface 29 causes the locking hook 2 to tend to rotate counterclockwise around the hinge 16.

[0048] The working method of the second embodiment of the magnetic induction automatic lock:

[0049] S1, the drawer is initially in the pulled-out state. At this time, the side of the swing arm 5 away from the limiting edge 10 is in contact with the limiting inclined wall 9; the locking hook 2 is in the "released" position. The locking hook 2 is pulled against the swing arm 5 by the traction line 18, and a fitting seam 28 is formed at the contact point; a section of the traction line 18 away from the locking hook 2 is wound in an arc shape in the groove of the outer ring of the coil 21; the section wound in an arc shape in the groove of the outer ring of the coil 21 is denoted as the arc segment 18.1 of the traction line.

[0050] S2, when the user pushes the drawer all the way down, the permanent magnet 6 and the magnetic field sensing device 11 are at their closest position, and the magnetic field strength sensed by the magnetic field sensing device 11 just exceeds the preset threshold. After receiving the sensor signal, the controller performs a logical judgment to confirm that the drawer is in place, and then sends a forward rotation command to the drive motor 15. At this time, the controller controls the drive motor 15, causing the worm gear 8 to drive the worm wheel 14, which in turn drives the swing shaft 12 through the gear transmission chain 13 in the lock housing 1, causing the swing arm 5 to rotate clockwise around the axis of the swing shaft 12 with the locking hook 2. During the process of the swing arm 5 rotating clockwise around the axis of the swing shaft 12 with the locking hook 2, there are two situations:

[0051] In the first scenario, after the user pushes the drawer all the way down, the locking lever 3 moves to the predetermined position along with the drawer and the floating locking lever seat 4. The drawer does not spring back, and the locking lever 3 remains stationary in the predetermined position. At this time, driven by the worm gear 8, the swing arm 5 rotates clockwise around the axis of the swing shaft 12 with the locking hook 2. The locking hook 2 and the locking lever 3 will never collide until the side of the swing arm 5 away from the limiting inclined wall 9 contacts the limiting edge 10. At this time, the locking hook 2 also reaches the "hooked" position, and the locking lever 3 is smoothly hooked by the locking hook 2. At this time, the drive motor 15 stops running. Due to the self-locking characteristics of the worm gear 8 and the worm wheel 14, the locking hook 2 remains stable in the "hooked" position, thereby locking the drawer stably. During the above process, the arc segment 18.1 of the traction line 18 is gradually released completely by the spool 21, and the spool 21 rotates adaptively against the torsion spring.

[0052] In the second scenario, after the user pushes the drawer all the way down, the locking lever 3 moves to the predetermined position along with the drawer and the floating locking lever seat 4. The drawer then experiences a slight rebound, and the locking lever 3, after stabilizing, slightly deviates from its predetermined position. At this time, driven by the worm gear 8, the swing arm 5, carrying the locking hook 2, rotates clockwise around the axis of the swing shaft 12. The inclined surface 29 on the locking hook 2 moves to contact the locking lever 3. At this point, the traction line 18 is fully released by the reel 21, but the extension of the traction line 18 has not yet coincided with the center of the reel 21. Figure 7 As shown in Figure b, the force F1 exerted by the locking rod 3 on the inclined plane 29 causes the locking hook 2 to rotate counterclockwise around the hinge 16, as... Figure 7 As shown in Figure b, the seam 28 becomes a gradually widening opening 30, thus allowing the locking rod 3 to transition from the inclined surface 29 to the inner arc surface 7, as... Figure 7 As shown in Figure c, the key to this transition process is that the rotation of the locking hook 2 compensates for the positional offset of the locking lever 3. This is equivalent to the locking hook 2 "actively adapting" to the position of the locking lever 3, avoiding rigid collisions. Subsequently, as the swing arm 5 carries the locking hook 2 clockwise around the axis of the swing shaft 12, since the total length of the traction line 18 remains constant, during the clockwise rotation of the swing arm 5 carrying the locking hook 2 around the axis of the swing shaft 12, the locking hook 2 rotates clockwise around the hinge 16 under the forced pull of the traction line 18. During this clockwise rotation, the force exerted by the inner arc surface 7 of the locking hook 2 on the locking lever 3 is denoted as F2. This F2 causes the floating locking lever seat 4 and the drawer to move inwards towards closing the drawer, restoring the originally rebounding drawer to its fully pushed-in state. This is an innovative "automatic correction" process: the length of the traction line 18 is fixed, and when the swing arm 5 continues... When the hook 2 cannot move forward synchronously due to being blocked by the locking rod 3 while the clockwise swing continues, the traction line 18 will force the hook 2 to rotate clockwise relative to the swing arm 5. This rotation will apply an inward component force F2 to the locking rod 3 through the inner arc surface 7. This force will push the drawer slightly inward through the locking rod 3 and the floating locking rod seat 4 until the locking rod 3 returns to the preset correct position. When the opening 30 returns to the fitting seam 28, the side of the swing arm 5 away from the limiting inclined wall 9 will just be in contact with the limiting edge 10. At this time, the traction line 18 will be fully released by the spool 21, and the extension line of the traction line 18 will pass through the center of the spool 21. Under the rigid pull of the traction line 18, the hook 2 cannot rotate around the hinge 16. At the same time, due to the self-locking characteristics of the worm gear 8 and worm wheel 14, the swing arm 5 will also enter a stable state, which will make the hook 2 just reach the "hooked" position, thus making the drawer stably locked. Figure 7As shown in Figure d, the core of the second embodiment lies in the flexible adaptive mechanism composed of hinge 16, traction line 18, and coil 21, which transforms the potential "hard collision" problem in the first embodiment into "soft contact" and "automatic guidance and correction." It not only tolerates drawer rebound errors but also actively corrects these errors during the locking process, ensuring reliable, smooth, and silent locking under various practical usage conditions, greatly improving the product's robustness and user experience.

[0053] When unlocking is required, the user unlocks via NFC. Specifically, an NFC card reader can be integrated into the cabinet. The user uses an authorized card or mobile phone to approach the sensing area. After the controller verifies the information, it controls the worm gear 8 to reverse. The drive motor 15 reverses, driving the swing arm 5 counterclockwise back to the "release" position via the transmission chain. The lock hook 2 disengages from the lock lever 3, and the drawer can be pulled out. Throughout the entire locking and unlocking cycle, the magnetic field sensing device 11 is only used to trigger the locking, resulting in extremely low power consumption. Maintaining the lock relies on mechanical self-locking, requiring no power supply. The unlocking action only occurs when needed, making the overall energy efficiency far higher than that of electromagnetic locks that require continuous power.

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A magnetic induction automatic lock, characterized in that: The lock includes a lock body (71) and a floating lock bar seat (4); a lock hook (2) and a magnetic field induction device (11) are provided on the side of the lock body (71) near the floating lock bar seat (4); a permanent magnet (6) and a lock bar (3) are fixedly connected on the side of the floating lock bar seat (4) near the lock body (71); the permanent magnet (6) and the lock bar (3) correspond to the magnetic field induction device (11) and the lock hook (2) respectively; the floating lock bar seat (4) is fixed to the bottom of the drawer and floats synchronously with the drawer; the lock body (71) is in the cabinet corresponding to the drawer; When the drawer is pushed to the bottom, the permanent magnet (6) and the magnetic field sensing device (11) are in a position close to each other. The magnetic field strength sensed by the magnetic field sensing device (11) just exceeds the preset threshold. At the same time, the lock hook (2) can swing to hook the lock bar (3) under the drive of the transmission device in the lock body (71).

2. The magnetic induction automatic lock according to claim 1, characterized in that: The lock body (71) includes a lock shell (1), the root of a lock hook (2) is connected to a swing arm (5), and a swing shaft (12) is fixedly connected to the end of the swing arm (5) away from the lock hook (2), and the swing shaft (12) is rotatably mounted on the lock shell (1).

3. The magnetic induction automatic lock according to claim 2, characterized in that: A drive motor (15) is fixedly installed inside the lock housing (1). The output end of the drive motor (15) is connected to a worm gear (8). A worm wheel (14) that cooperates with the worm gear (8) is provided inside the lock housing (1). The worm wheel (14) is connected to the swing shaft (12) through a gear transmission chain (13) inside the lock housing (1).

4. The magnetic induction automatic lock according to claim 3, characterized in that: The lock housing (1) is provided with a limiting inclined wall (9) and a limiting edge (10); When the lock hook (2) is in the "hooked" position, the side of the swing arm (5) away from the limiting inclined wall (9) is limited to contact the limiting edge (10). When the locking hook (2) is in the "release" position, the side of the swing arm (5) away from the limiting edge (10) is limited to contact the limiting inclined wall (9).

5. The magnetic induction automatic lock according to claim 4, characterized in that: The inner side of the lock hook (2) has an inner arc surface (7); when the lock hook (2) is in the "hook" position, the inner arc surface (7) slides tangentially to the lock bar (3) or there is a gap; the center of the inner arc surface (7) coincides with the axis of the swing shaft (12).

6. The magnetic induction automatic lock according to claim 5, characterized in that: The tail end of the locking hook (2) is fixedly connected to the end of the swing arm (5).

7. The magnetic induction automatic lock according to claim 5, characterized in that: The tail end of the lock hook (2) is hinged to the end of the swing arm (5) by a hinge (16); a wire reel compartment (65) is provided inside the lock housing (1), and a wire reel (21) is provided inside the wire reel compartment (65). A wire groove is provided around the outer ring of the wire reel (21), and the inner ring of the wire reel (21) is rotatably mounted on the wire reel shaft (20) by a bearing; a traction wire passage channel (17) is provided on the part of the swing arm (5) near the hinge (16), and a wire threading groove (19) overlapping the traction wire passage channel (17) is hollowed out on the limiting inclined wall (9); it also includes a traction wire (18) made of high-strength metal fiber or other fiber, which passes through the traction wire passage channel (17) and the wire threading groove (19); one end of the traction wire (18) is fixedly connected to the wire groove of the wire reel (21), and the other end is fixedly connected to the tail end of the lock hook (2); It also includes a torsion spring that applies clockwise torque to the reel (21). The hook (2) swings down around the hinge (16) under the pull of the traction line (18) to the lower position to abut against the swing arm (5), forming a fitting seam (28) at the abutment. When the swing arm (5) swings to the limit engagement limit edge (10) and the hook (2) is in the "hooked" state, the traction line (18) is completely released by the reel (21), and the extension line of the traction line (18) passes through the center of the reel (21). The end of the lock hook (2) is provided with a section of inclined surface (29) that is connected to the inner arc surface (7) at an obtuse angle. When the lock hook (2) swings with the swing arm (5) and the inclined surface (29) comes into contact with the lock rod (3), the force F1 exerted by the lock rod (3) on the inclined surface (29) causes the lock hook (2) to tend to rotate counterclockwise around the hinge (16).

8. The magnetic induction automatic lock according to claim 7, characterized in that: The torque provided by the torsion spring is converted into the tension of the traction line (18) without significantly counteracting or promoting the swing arm (5).

9. The working method of the magnetic induction automatic lock according to claim 8, characterized in that: When the user pushes the drawer to the bottom, the magnetic field strength sensed by the magnetic field sensor (11) just exceeds the preset threshold; the controller controls the drive motor (15) so that the worm gear (14) drives the swing shaft (12) through the gear transmission chain (13) in the lock case (1), so that the swing arm (5) with the lock hook (2) rotates clockwise around the axis of the swing shaft (12); so that the swing arm (5) with the lock hook (2) rotates clockwise around the axis of the swing shaft (12) until the side of the swing arm (5) away from the limiting inclined wall (9) is limited to contact the limiting edge (10). When unlocking is required, the user unlocks via NFC, and the controller controls the worm gear (8) to reverse.

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