Magnetic type limiting unlocking assembly and electric door closer comprising same

Abstract

This invention relates to a magnetic limit unlocking assembly and an electric door closer including the same. The limit unlocking assembly includes a limit bracket, a rotating block, a permanent magnet, and a force-relieving retaining mechanism. The rotating block is pivotally connected to the inner cavity of the limit bracket. A limit end protruding to the left is provided on the lower left side of the rotating block. A limit groove cooperating with the limit end is provided on the left wall of the inner cavity of the limit bracket. An electromagnet is fixed on the right side of the rotating block. An arc groove is provided on the top surface of the rotating block. The force-relieving retaining mechanism includes a force-relieving spring and a ball bearing. The advantages of this invention are: the permanent magnet is directly fixed to the slider and engages with the unenergized electromagnet when locked in the limit position, meaning no power is consumed in the normally open state, saving energy; and the limit position is automatically engaged when the door is fully open, making it convenient to use. The newly designed force-relieving retaining mechanism reduces the impact of forced opening on the fixed pin, and the force-relieving spring prevents the rotating block from jamming, avoiding unexpected situations where forced opening fails. The improved structure is simpler, with fewer parts, reducing costs.

Description

Technical Field

[0001] This invention relates to the field of fire door closers, specifically to a magnetic limit unlocking assembly and an electric door closer including the same. Background Technology

[0002] Electric fire door closers keep fire doors open under normal conditions. In the event of a fire, the system controls the door to close, isolating the fire source and preventing the spread of fire and smoke to adjacent fire compartments. Normally open electric fire door closers have two main operating states. Under normal conditions, the built-in limit mechanism of the electric fire door closer is activated, keeping the fire door open. When a fire alarm is triggered, the communication module of the electric fire door closer receives a closing signal from the system host, disabling the limit mechanism and closing the fire door. After the door is fully closed, information is sent back to the system host.

[0003] Currently, the existing electric door closers for fire doors on the market (such as CN215485401U, a limit mechanism for a normally open door closer, and CN217872363U, a door closer limit locking and unlocking component and an electric door closer containing the same) all have at least one of the following problems: (1) The fire door needs to be continuously powered to maintain the limit when it is normally open, which consumes a lot of power and increases the system load; (2) The limit unlocking mechanism is complex and has many material parts (including connecting frame, limit hook, electromagnet, limit rotating block, limit roller, first spring, push rod, slider, slot, second spring, extension, limit post, first pin, second pin, third pin, spring positioning post and reset rod, etc.), resulting in high cost; (3) The fire door needs to be manually reset after it is opened to make the limit effective, and it cannot achieve automatic mechanical limit. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a magnetic limit unlocking component and an electric door closer including the same, in order to overcome the above-mentioned shortcomings of conventional electric door closers and their limit unlocking mechanisms in the prior art.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A magnetic suction type limiting and unlocking component includes a limiting bracket, a rotating block, a permanent magnet, and a force-relieving and retaining mechanism. The rotating block is pivotally connected to the inner cavity of the limiting bracket through the middle. The lower left side of the rotating block is provided with a limiting end protruding to the left. The left wall of the inner cavity of the limiting bracket is provided with a limiting groove that cooperates with the limiting end. An electromagnet is fixed on the right side of the rotating block. The top surface of the rotating block is provided with an arc groove. The force-relieving and retaining mechanism includes a force-relieving spring and a ball. The force-relieving spring is vertically arranged and its top end abuts against the top wall of the inner cavity of the limiting bracket. The lower end of the force-relieving spring presses the ball into the arc groove. The permanent magnet is fixedly arranged on the top surface of the door closer slider and forms a locking groove on the top surface of the slider that cooperates with the lower right part of the rotating block. When the electromagnet and the permanent magnet generate attraction or repulsion at the locking groove, the rotating block rotates around the central pivot to correspondingly limit and lock or unlock the slider.

[0006] Based on the above technical solution, the present invention can be further improved as follows.

[0007] Furthermore, the permanent magnet is fixed in a groove on the top surface of the slider. The upper surface of the permanent magnet is inclined from left to right and forms the bottom surface of the locking groove. The right side wall of the locking groove is set as a slope surface for interacting with the lower right corner of the rotating block.

[0008] Furthermore, the limiting bracket is a cuboid block, and the inner cavity of the limiting bracket is a square groove located in the middle of the cuboid block with its opening facing downwards. The limiting bracket has fixing holes for connecting locking bolts at both ends. Corresponding through holes for the fixing pin to pass through are opened on the front and rear side walls of the square groove. The rotating block has an oblong hole that passes through the front and rear for the fixing pin to pass through. The rotating block is pivotally connected to the limiting bracket through the oblong hole and the fixing pin. After the electromagnet and the permanent magnet are attracted and locked or repelled and unlocked, the fixing pin is pressed against the upper edge of the oblong hole. When the slider pushes the rotating block to the left to forcibly unlock, the rotating block moves upward relative to the fixing pin and rotates counterclockwise by an angle.

[0009] Furthermore, after the electromagnet and the permanent magnet repel and unlock each other, the rotating block rotates to a horizontal position. At this time, the ball is pressed against the lowest point of the arc groove, and the vertical central axis of the ball is located to the left of the vertical line where the long axis of the waist-shaped hole is located, and the distance between the vertical central axis and the long axis is 3-10mm.

[0010] Furthermore, the top wall of the square groove is provided with a downwardly protruding positioning post, and the upper end of the unloading spring is sleeved on the positioning post and abuts against the top wall of the square groove.

[0011] Furthermore, two limiting protrusions are provided at intervals along the lower edge of the left side wall of the square groove, forming the limiting groove between the two limiting protrusions. After the electromagnet and the permanent magnet are attracted and locked, the limiting end abuts against the upper limiting protrusion. After the electromagnet and the permanent magnet are repelled and unlocked, the limiting end abuts against the lower limiting protrusion.

[0012] Furthermore, the lower right side surface of the cuboid block is provided with a downward protruding baffle. The baffle extends into the groove on the lower surface of the door closer slide and is adapted to the width of the groove. After the electromagnet and the permanent magnet are attracted and locked, the right end of the slider abuts against the left end face of the baffle.

[0013] Furthermore, the electromagnet is a circular or rectangular suction cup type electromagnet, and the limiting bracket is also equipped with a control circuit board that is electrically connected to the electromagnet.

[0014] Furthermore, the right side of the rotating block is provided with an installation groove that opens downward for the electromagnet to be installed, the right side of the limiting bracket is provided with an insertion groove for the control circuit board to be installed, and the right side wall of the inner cavity of the limiting bracket is provided with a wire passage hole that communicates with the insertion groove.

[0015] The present invention also provides an electric door closer, which includes the above-described magnetic limit and unlocking component.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] This invention represents a groundbreaking improvement to the limit and unlocking component of a normally open fire door electric door closer. It eliminates the complex structure commonly used in normally open fire door electric door closers, which typically includes numerous material components such as push-pull telescopic electromagnets and push-pull mechanisms. Instead, a permanent magnet is fixed in the locking groove of the slider. The permanent magnet on the slider interacts with a suction cup electromagnet fixed to the rotating block. When the door is open, the electromagnet is de-energized, and the slider is locked by the permanent magnet attracting the end of the electromagnet core into the locking groove. In other words, when the door is in the normally open state, the electromagnet does not require power, effectively saving energy. Furthermore, when the door is fully open, the permanent magnet automatically engages with the de-energized electromagnet, locking the slider without manual reset, making it convenient to use.

[0018] This invention also improves the structure of the force-relieving mechanism by designing a waist-shaped hole, an arc groove, balls, and a force-relieving spring. When the door is forcibly closed, the right side of the slider locking groove forcibly pushes the rotating block, causing the right side of the rotating block to move upward and rotate counterclockwise around the fixed pin. Since the waist-shaped hole provides a certain space for the fixed pin and the rotating block to move in the long axis direction of the waist-shaped hole, the slider has a large impact force on the rotating block when the door is forcibly closed. The space provided by the waist-shaped hole makes the interaction force between the fixed pin and the rotating block relatively small, and the larger force is basically borne by the balls and the force-relieving spring above, avoiding damage to the fixed pin due to the impact of the forced door closing. The lower end of the force-relieving spring presses the balls into the arc groove. When the rotating block is impacted, the balls can move in the arc groove, which can effectively reduce the torsional effect on the force-relieving spring, ensure that the force-relieving spring is mainly subjected to axial force, make the force-relieving spring more durable, and avoid the problem of the rotating block getting stuck due to the force-relieving spring being subjected to a large non-axial force when the door is forcibly closed.

[0019] The magnetic limit unlocking assembly provided by this invention has a significantly simplified structure compared to existing limit unlocking assemblies with push-pull electromagnets. The structure is simple, and the number of parts used is significantly reduced, with only one pin and one rotating part. This effectively reduces production costs and makes installation and maintenance more convenient. Attached Figure Description

[0020] Figure 1 An isometric view of the magnetic locking and unlocking assembly provided by the present invention;

[0021] Figure 2 for Figure 1 A top view of the magnetic limit unlocking component shown;

[0022] Figure 3 for Figure 2 The magnetic limit unlocking component shown is a cross-sectional view along AA.

[0023] Figure 4 for Figure 1 The main view of the magnetic limit unlocking component shown;

[0024] Figure 5 for Figure 4 The magnetic limit unlocking assembly shown is a cross-sectional view along BB.

[0025] Figure 6 for Figure 1 An exploded view of the magnetic limit unlocking component shown.

[0026] Figure 7 for Figure 6 Assembly drawing of the rotating block, fixed pin, electromagnet and unloading spring;

[0027] Figure 8 for Figure 1The cross-sectional view shown is of the magnetic limit unlocking component in the unlocked state after it is installed in the slide of the electric door closer.

[0028] Figure 9 for Figure 1 The cross-sectional view shown is of the magnetic limit unlocking component in the magnetic locking state after being installed in the electric door closer slide groove.

[0029] Figure 10 The present invention provides an electric door closer, wherein a slide groove is fitted with a Figure 1 The magnetic limit unlocking component shown.

[0030] Figure 11 for Figure 10 The diagram shows the electric door closer after it has been installed on the door frame and door leaf.

[0031] The attached diagram lists the components represented by each number as follows:

[0032] 1. Limiting bracket; 2. Rotating block; 3. Permanent magnet; 4. Limiting end; 5. Limiting groove; 6. Electromagnet; 7. Arc groove; 8. Unloading spring; 9. Ball bearing; 10. Sliding block; 11. Locking groove; 12. Groove; 13. Sloping surface; 14. Fixing pin; 15. Through hole; 16. Waist-shaped hole; 17. Positioning post; 18. Limiting protrusion; 19. Stop bar; 20. Slide groove; 21. Control circuit board; 22. Mounting groove; 23. Insertion groove; 24. Wire passage hole. Detailed Implementation

[0033] The principles and features of the present invention are described below with reference to the accompanying drawings and specific embodiments. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0034] In the description of this invention, if terms such as "upper," "lower," "left," "right," "top," "bottom," "inner," and "outer" are used to indicate the orientation or positional relationship, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] like Figures 1 to 7As shown, this invention provides a magnetically attached limiting and unlocking assembly, which includes a limiting bracket 1, a rotating block 2, a permanent magnet 3, and a force-relieving and retaining mechanism. The rotating block 2 is pivotally connected to the inner cavity of the limiting bracket 1 via its central portion. The lower left side of the rotating block 2 has a left-protruding limiting end 4. The left wall of the inner cavity of the limiting bracket 1 has a limiting groove 5 that mates with the limiting end 4. An electromagnet 6 is fixed to the right side of the rotating block 2. The top surface of the rotating block 2 has an arc groove 7. The force-relieving and retaining mechanism includes a force-relieving spring 8 and... The ball bearing 9 and the unloading spring 8 are vertically arranged and their top ends are pressed against the top wall of the inner cavity of the limiting bracket 1. The lower end of the unloading spring 8 presses the ball bearing 9 into the arc groove 7. The permanent magnet 3 is fixed on the top surface of the door closer slider 10 and forms a locking groove 11 on the top surface of the slider 10 that cooperates with the lower right part of the rotating block 2. When the electromagnet 6 and the permanent magnet 3 generate attraction or repulsion at the locking groove 11, the rotating block 2 rotates around the central pivot to correspondingly limit and lock or unlock the slider 10.

[0036] It should be noted that the ball bearing can be a steel ball or a smooth plastic ball made of wear-resistant hard plastic; the limiting end is a protruding head (thin plate-shaped) that extends into the limiting groove. When the rotating block moves up and down and rotates, this protruding head can move up and down within the limiting groove. When the permanent magnet and the electromagnet are attracted, the protruding head is pressed tightly against the upper wall of the limiting groove (e.g., Figure 3 and Figure 9 As shown), when the electromagnet is energized, it repels the permanent magnet and unlocks. After the slider moves away from under the rotating block, the rotating block rotates to the left under the action of the unloading spring until the protrusion is pressed against the lower wall of the limiting groove (as shown). Figure 8 (As shown). The permanent magnet can be a disc with a hole in the center or a similar shape. The permanent magnet is fixed to the slider by a bolt passing through its center. The slider has countersunk holes for bolt installation. To prevent damage to the permanent magnet, a protective coating or plastic protective sleeve can be applied to its surface.

[0037] In one embodiment of the present invention, the permanent magnet 3 is fixed in a groove 12 opened on the top surface of the slider 10. The upper surface of the permanent magnet 3 is inclined from left to right and forms the bottom surface of the locking groove 11. The right side wall of the locking groove 11 is set as a ramp surface 13 for interacting with the lower right corner of the rotating block 2. The locking groove is equivalent to setting a hook structure on the upper surface of the slider to engage with the rotating block in the limiting bracket. When the limiting is engaged, the hook structure is equivalent to engaging with the rotating block. In use, as... Figure 3 As shown, the slider is horizontal, and the right side of the locking groove on the upper surface is deeper than the left side. It matches the inclined lower surface of the rotating block that rotates to the right and down by an angle due to magnetic attraction. When attracted, the lower surface of the electromagnet can fit well with the upper surface of the permanent magnet that forms the bottom of the locking groove.

[0038] In one embodiment of the present invention, such as Figure 1 , Figure 3 and Figure 6 As shown, the limiting bracket 1 is a cuboid block. The inner cavity of the limiting bracket 1 is a square groove located in the middle of the cuboid block with its opening facing downwards. The limiting bracket 1 has fixing holes for connecting locking bolts at both ends. The front and rear side walls of the square groove have corresponding through holes 15 for the fixing pin 14 to pass through. The rotating block 2 has a waist-shaped hole 16 that passes through the front and rear for the fixing pin 14 to pass through. The rotating block 2 is pivotally connected to the limiting bracket 1 through the waist-shaped hole 16 and the fixing pin 14. After the electromagnet 6 and the permanent magnet 3 are engaged and locked or repelled and unlocked, the fixing pin 14 is pressed against the upper edge of the waist-shaped hole 16. When the slider 10 pushes the rotating block 2 to the left to forcibly unlock, the rotating block 2 moves upward relative to the fixing pin 14 and rotates counterclockwise by an angle.

[0039] It should be noted that the fixing pin is a round shaft, the outer diameter of which is equivalent to the short shaft length of the oblong hole (clearance fit), and the two ends of the fixing pin are located in the through holes on the front and rear side walls of the limiting bracket.

[0040] In one embodiment of the present invention, such as Figure 8 As shown, after the electromagnet 6 and the permanent magnet 3 repel and unlock, the rotating block 2 rotates to a horizontal position. At this time, the waist-shaped hole and the fixed pin's central axis in the vertical direction coincide, or in other words, they share the same symmetry plane in the vertical direction. That is, at this time, the ball 9 is pressed against the lowest point of the arc groove 7, and the vertical central axis of the ball 9 is located to the left of the vertical line where the long axis of the waist-shaped hole 16 is located, and the distance between the vertical central axis and the long axis is 3-10mm. Figure 8 and Figure 9 The change in the markings on the vertical center axis shows that when fully unlocked, the distance between the vertical center axis of ball 9 and the fixed pin is slightly greater than when it is locked. This indicates that when locked, the ball is pressed against the left side of the circular groove of the rotating block and undergoes a slight displacement to the right.

[0041] In one embodiment of the present invention, the top wall of the square groove is provided with a downwardly protruding positioning post 17, and the upper end of the unloading spring 8 is sleeved on the positioning post 17 and abuts against the top wall of the square groove. The upper end of the unloading spring can simply abut against the top wall of the square groove without being fixed, and the lower end of the unloading spring is sleeved on a ball and the lower end of the unloading spring is ground flat. The inner diameter of the lower end opening is significantly smaller than the diameter of the ball (sphere). The ball can be locked in the lower end of the unloading spring or the ball can be pressed against the lower end of the unloading spring and still roll relative to the unloading spring. The left peripheral edge of the arc groove is provided with a platform surface. When it is engaged and locked, the lower end surface of the unloading spring can be pressed against the platform surface.

[0042] In one embodiment of the present invention, two limiting protrusions 18 are provided at intervals along the lower edge of the left side wall of the square groove, and the limiting groove 5 is formed between the two limiting protrusions 18. After the electromagnet 6 and the permanent magnet 3 are attracted and locked, the limiting end 4 abuts against the upper limiting protrusion 18. After the electromagnet 6 and the permanent magnet 3 are repelled and unlocked, the limiting end 4 abuts against the lower limiting protrusion 18.

[0043] In one embodiment of the present invention, a downwardly protruding stop bar 19 is provided on the lower right side surface of the cuboid block. The stop bar 19 extends into the groove on the lower surface of the door closer slide groove 20 and is adapted to the width of the groove. Here, adaptation means that the stop bar is slightly narrower than the width of the groove, ensuring that the stop bar can play a certain guiding role when the limiting bracket is initially installed into the slide groove. Even if the front-to-back dimension of the limiting bracket is much smaller than the corresponding dimension of the inner cavity of the slide groove, the installation of the limiting bracket can still be completed with the cooperation of the stop bar and the groove. After the electromagnet 6 and the permanent magnet 3 are attracted and locked, the right end of the slider 10 abuts against the left end face of the stop bar 19. That is, the left end of the stop bar is the limiting component for the door to be fully opened. When the door is opened to the maximum position, the right end of the slider is pressed against the left end of the stop bar, at which time the permanent magnet is attracted to the lower end face of the electromagnet that is not energized.

[0044] In one embodiment of the present invention, the electromagnet 6 is a circular or rectangular suction cup type electromagnet, and the limiting bracket 1 is further provided with a control circuit board 21 electrically connected to the electromagnet 6. It should be noted that the electromagnet in the present invention has a fixed iron core. When not energized, the iron core is non-magnetic and its function is to attract the permanent magnet; when energized, the iron core generates magnetism, and its lower magnetic pole is opposite to the magnetic pole on the upper surface of the permanent magnet, resulting in repulsion.

[0045] In one embodiment of the present invention, the rotating block 2 has a mounting groove 22 with an opening facing downward for the electromagnet 6 to be installed on the right side, the limiting bracket 1 has an insertion groove 23 for the control circuit board 21 to be installed on the right side, and the limiting bracket 1 has a wire hole 24 communicating with the insertion groove 23 on the right side wall of the inner cavity.

[0046] The present invention also provides an electric door closer, such as Figure 8-10 As shown, it includes the aforementioned magnetic limit unlocking assembly. When this fire door electric door closer is installed on the door frame and door leaf, it mainly consists of five parts, such as... Figure 11As shown, A – fire door leaf, B – fire door frame, C – fire door linkage track (i.e., door closer track 20), D – door opening and closing actuator linkage, E – hydraulic device. The fire door linkage track (C) contains the magnetic limit unlocking component and electronic device with signal detection and feedback functions of this invention, which can remotely control the door closer's action, thus enabling timely closure of the fire door in the event of a fire. The opening and closing of the fire door mainly utilizes the hydraulic device to provide power to drive the linkage, thereby driving the slider to slide along the track in the open rail (groove), thus controlling the opening and closing of the fire door leaf. Considering that the fire door needs to close quickly and stably in the event of a fire, the structure restricting the slider's movement needs to both limit and lock the slider, and unlock and release the slider to move along the track, thereby closing the fire door.

[0047] In this invention, the electromagnet 6 is fixed in the mounting groove 22 of the rotating block 2, and the two are integrated. When the fire door is opened to the designated position, the slider 10 slides along the opening track of the slide groove 20 to the bottom of the magnetic limit unlocking component. When the slider 10 moves to the limit position of the limit bracket 1 and is pressed against the stop bar 19 and can no longer move, because the slider 10 contains a permanent magnet 3, its magnetic attraction acts on the electromagnet at the right end of the rotating block 2, causing the rotating block 2 to rotate clockwise along the fixed pin shaft 14. The slider 10 and the electromagnet 6 approach each other and attract each other, thereby achieving the limit locking of the slider 10. The limit is completed by mechanical limit, and there is no need to manually reset the limit. It achieves the purpose of automatic limit after the door is opened. No power is consumed when the door is in the normally open state.

[0048] The principle and solution of electric door closing: When a fire occurs, the remote control room issues a door closing command. The electromagnet 6 is energized through the switching action of the control circuit board 21. During the energization process, an N polarity is generated on the lower end face of the electromagnet 6. At this time, the end face of the permanent magnet that attracts it is also N pole. The two generate a magnetic pole effect of like poles repelling each other, forcing the rotating block 2 to rotate counterclockwise, thereby releasing the limit. Under the action of the hydraulic device, the fire door closes immediately.

[0049] The principle and solution for forced closing: In the event of a fire, sometimes due to circuit faults, the electronically controlled door closing command may not be effectively transmitted to the door closer. In this case, it is necessary to manually force the fire door to close. The magnetic limit unlocking component is always in the attracted state with the slider 10. The slider 10 is subjected to a horizontal force to the left, which forces the rotating block 2 to move upward. Because the rotating block 2 is designed with a waist hole, the rotating block can move up and down relative to the fixed pin. Since there is a ball 9 pressed by the relief spring 8 in the arc groove 7 of the rotating block 2, when it is squeezed by the external force, the relief spring 8 is compressed, and due to the rotation of the rotating block 2, the contact point between the ball and the arc groove is also deviated from the lowest point. The pressure of the ball on the rotating block increases and points to the lower left along the radial direction of the ball. This makes it easier for the slider 10 to get rid of the magnetic attraction of the permanent magnet and electromagnet at the right end when subjected to the forced closing force, thereby releasing the limit and achieving the purpose of forced closing.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magnetic limit unlocking component, characterized in that, The device includes a limiting bracket (1), a rotating block (2), a permanent magnet (3), and a force-relieving and retaining mechanism. The rotating block (2) is pivotally connected to the inner cavity of the limiting bracket (1) through the middle. The lower left side of the rotating block (2) is provided with a limiting end (4) protruding to the left. The left wall of the inner cavity of the limiting bracket (1) is provided with a limiting groove (5) that cooperates with the limiting end (4). An electromagnet (6) is fixed on the right side of the rotating block (2). The top surface of the rotating block (2) is provided with an arc groove (7). The force-relieving and retaining mechanism includes a force-relieving spring (8) and a ball (9). (8) Vertically arranged and with its top end pressed against the inner wall of the limiting bracket (1), the lower end of the unloading spring (8) presses the ball (9) into the arc groove (7), the permanent magnet (3) is fixedly installed on the top surface of the door closer slider (10) and forms a locking groove (11) on the top surface of the slider (10) that cooperates with the lower right part of the rotating block (2), when the electromagnet (6) and the permanent magnet (3) generate attraction or repulsion at the locking groove (11), the rotating block (2) rotates around the central pivot to correspondingly limit and lock or unlock the slider (10); The limiting bracket (1) is a rectangular block. The inner cavity of the limiting bracket (1) is a square groove located in the middle of the rectangular block and facing downward. The limiting bracket (1) has fixing holes for connecting locking bolts at both ends. The front and rear side walls of the square groove have corresponding through holes (15) for the fixing pin (14) to pass through. The rotating block (2) has a waist-shaped hole (16) that passes through the front and rear for the fixing pin (14) to pass through. The rotating block (2) is pivotally connected to the limiting bracket (1) through the waist-shaped hole (16) and the fixing pin (14). After the electromagnet (6) and the permanent magnet (3) are attracted and locked or repelled and unlocked, the fixing pin (14) is pressed against the upper edge of the waist-shaped hole (16). When the slider (10) pushes the rotating block (2) to the left to forcibly unlock, the rotating block (2) moves upward relative to the fixing pin (14) and rotates counterclockwise by an angle.

2. The magnetic limit unlocking component according to claim 1, characterized in that, The permanent magnet (3) is fixed in the groove (12) opened on the top surface of the slider (10). The upper surface of the permanent magnet (3) is inclined from left to right and forms the bottom surface of the locking groove (11). The right side wall of the locking groove (11) is set as a slope (13) for interacting with the lower right corner of the rotating block (2).

3. The magnetic limit unlocking component according to claim 1, characterized in that, After the electromagnet (6) and the permanent magnet (3) repel and unlock, the rotating block (2) rotates to a horizontal position. At this time, the ball (9) is pressed against the lowest point of the arc groove (7), and the vertical center axis of the ball (9) is located to the left of the vertical line where the long axis of the waist-shaped hole (16) is located, and the distance between the vertical center axis and the long axis is 3-10mm.

4. The magnetic limit unlocking component according to claim 1, characterized in that, The top wall of the square groove is provided with a downward protruding positioning post (17), and the upper end of the unloading spring (8) is sleeved on the positioning post (17) and abuts against the top wall of the square groove.

5. A magnetic limit unlocking assembly according to claim 1, characterized in that, Two limiting protrusions (18) are provided at intervals along the lower edge of the left side wall of the square groove, forming the limiting groove (5) between the two limiting protrusions (18). After the electromagnet (6) and the permanent magnet (3) are attracted and locked, the limiting end (4) abuts against the upper limiting protrusion (18). After the electromagnet (6) and the permanent magnet (3) are repelled and unlocked, the limiting end (4) abuts against the lower limiting protrusion (18).

6. A magnetic limit unlocking component according to claim 1, characterized in that, The lower right side surface of the rectangular block is provided with a downward protruding baffle (19). The baffle (19) extends into the groove on the lower surface of the door closer slide groove (20) and is adapted to the width of the groove. After the electromagnet (6) and the permanent magnet (3) are attracted and locked, the right end of the slider (10) abuts against the left end face of the baffle (19).

7. A magnetic locking and unlocking assembly according to any one of claims 1 to 6, characterized in that, The electromagnet (6) is a circular or rectangular suction cup type electromagnet, and the limiting bracket (1) is also provided with a control circuit board (21) that is electrically connected to the electromagnet (6).

8. A magnetic limit unlocking assembly according to claim 7, characterized in that, The rotating block (2) has an installation groove (22) with an opening facing downward for the electromagnet (6) to be installed on the right side. The limit bracket (1) has an insertion groove (23) for the control circuit board (21) to be installed on the right side. The limit bracket (1) has a wire hole (24) communicating with the insertion groove (23) on the right side wall of the inner cavity.

9. An electric door closer, characterized in that, Includes a magnetic limit unlocking component as described in any one of claims 1 to 8.

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