CN117468812A - Magnetic-type limiting unlocking component and electric door closer comprising same - Google Patents

Abstract

The invention relates to a magnetic type limiting unlocking component and an electric door closer comprising the same, wherein the limiting unlocking component comprises a limiting bracket, a rotating block, a permanent magnet and a force unloading and holding mechanism, the rotating block is pivoted in an inner cavity of the limiting bracket, a left-side lower part of the rotating block is provided with a left-protruding limiting end head, the left wall of the inner cavity of the limiting bracket is provided with a limiting groove matched with the limiting end head, the right side of the rotating block is fixedly provided with an electromagnet, the top surface of the rotating block is provided with an arc groove, and the force unloading and holding mechanism comprises a force unloading spring and a ball. The invention has the advantages that the permanent magnet is directly fixed on the sliding block and is attracted with the electromagnet which is not electrified when the locking limiting is performed, namely, the normally open door state does not need to consume electric energy, the energy is saved, and the automatic attracting limiting is performed when the door is opened in place, so that the use is convenient; the newly designed unloading force retaining mechanism can lighten the impact of the forced door opening on the fixed pin shaft, and the unloading force spring can not cause the locking of the rotating block, so that the accident of failure of the forced door opening is avoided; the improved structure is simpler, parts are fewer, and the cost is reduced.

Description

Magnetic-type limiting unlocking component and electric door closer comprising same

Technical Field

The invention relates to the field of fireproof door closers, in particular to a magnetic limiting unlocking component and an electric door closer comprising the same.

Background

The electric door closer for the fireproof door is characterized in that the fireproof door is kept normally open in a daily state, and when a fire accident occurs, the fireproof door is closed through system control, a fire source is isolated, and fire and thick smoke are prevented from spreading to adjacent fireproof subareas. The electric door closer of the normally open fireproof door mainly has two working states. In a daily state, a limiting mechanism arranged in the electric door closer of the fireproof door takes effect, so that the fireproof door is kept normally open; when a fire disaster alarm occurs, the communication module of the electric fireproof door closer receives a door closing signal of the system host, so that the limit is invalid, the fireproof door is closed, and information is fed back to the system host after the fireproof door is closed in place.

Currently, existing fire door electric door closers (such as a limit mechanism of a normally open door closer of CN215485401U and a limit locking and unlocking assembly of a door closer of CN 217872363U) in the market basically have at least one of the following problems: (1) The fireproof door needs to be continuously powered and kept limited in a normally open state, so that the power consumption is high, and the system load is increased; (2) The limiting unlocking mechanism is complex, the material parts are more (comprising a connecting frame, a limiting clamping hook, an electromagnet, a limiting rotating block, a limiting roller, a first spring, a push rod, a sliding block, a clamping groove, a second spring, an extension part, a limiting column, a first pin roll, a second pin roll, a third pin roll, a spring positioning column, a reset rod and the like), and the cost is high; (3) After the fireproof door is opened, the fireproof door needs to be manually reset to enable the limiting effect, and mechanical automatic limiting cannot be achieved.

Disclosure of Invention

The invention aims to solve the technical problem of providing a magnetic limiting unlocking assembly and an electric door closer comprising the same, and aims to overcome the defects of the conventional electric door closer and the limiting unlocking mechanism thereof in the prior art.

The technical scheme for solving the technical problems is as follows: the utility model provides a spacing unblock subassembly of magnetic attraction type, its includes spacing support, rotating block, permanent magnet and unloads the power hold mechanism, the rotating block through the middle part pin joint in spacing support inner chamber, the left side lower part of rotating block is equipped with left convex spacing end, spacing support inner chamber left wall be equipped with spacing end complex spacing groove, the right side of rotating block is fixed with the electro-magnet, the top surface of rotating block is equipped with the circular arc groove, it includes unloads power spring and ball to unload the power hold mechanism, unload power spring vertical setting and top with spacing support inner chamber roof supports tightly, unload the lower extreme of power spring with the ball compress tightly in the circular arc inslot, the permanent magnet is fixed to be located door closer slider top surface and be in slider top surface form with rotating block right lower part complex locking groove, the electro-magnet is in when locking groove department produces the actuation or rejection, the rotating block rotates around middle part pin joint department in order to correspond spacing locking or unblock the slider.

On the basis of the technical scheme, the invention can be improved as follows.

Further, the permanent magnet is fixed in a groove formed in the top surface of the sliding block, the upper surface of the permanent magnet is inclined in a left-high-right low-inclined mode and forms the bottom surface of the locking groove, and the wall of the right side groove of the locking groove is a slope surface for interacting with the lower right corner of the rotating block.

Further, the spacing support is cuboid form block, spacing support inner chamber is for locating cuboid form block middle part and opening square groove down, both ends all are equipped with the fixed orifices that is used for connecting locking bolt about the spacing support, correspond on the front and back lateral wall of square groove and seted up the through-hole that supplies the fixed pin axle to penetrate, be equipped with the front and back on the rotating block and run through supplies the waist shape hole that the fixed pin axle passed, the rotating block pass through waist shape hole and fixed pin axle realize with spacing support pin joint, the electro-magnet with after permanent magnet actuation locking or rejection unblock are accomplished, the fixed pin axle all with the upper edge in waist shape hole supports tightly, the slider promotes leftwards when the rotating block is unblocked by force, the rotating block is relative the fixed pin axle is upwards moved and anticlockwise rotates an angle.

Further, after the electromagnet and the permanent magnet repel and unlock are completed, the rotating block just rotates to a horizontal state, at this time, the balls are pressed on the lowest point of the circular arc groove, the vertical central axis of the balls is located on the left side of the vertical line where the long axis of the kidney-shaped hole is located, and the distance between the vertical central axis and the long axis is 3-10mm.

Further, the top wall of the square groove is provided with a positioning column protruding downwards, and the upper end of the force unloading spring is sleeved on the positioning column and abuts against the top wall of the square groove.

Further, two spacing sand strips are arranged at the lower edge of the left side wall of the square groove at intervals up and down, the spacing groove is formed between the two spacing sand strips, the electromagnet and the permanent magnet are in attraction and locking, the spacing end is propped against the spacing sand strips above, the electromagnet and the permanent magnet are in repulsion and unlocking, and the spacing end is propped against the spacing sand strips below.

Further, the lower surface of the right side of the cuboid block body is provided with a baffle strip protruding downwards, the baffle strip stretches into a notch of the lower surface of the sliding groove of the door closer and is adaptive to the width of the notch, and after the electromagnet is in actuation locking with the permanent magnet, the right end of the sliding block is just abutted to the left end face of the baffle strip.

Further, the electromagnet is a round or rectangular sucker type electromagnet, and a control circuit board which is in ferroelectric connection with the electromagnet is further arranged in the limiting support.

Further, the right side of the rotating block is provided with a mounting groove with an opening downwards for the electromagnet to be mounted, the right side of the limiting support is provided with a mounting groove for the control circuit board to be mounted, and the right side wall of the inner cavity of the limiting support is provided with a wire passing hole communicated with the mounting groove.

The invention also provides an electric door closer which comprises the magnetic limiting unlocking component.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, the limit unlocking component of the normally open type fireproof door electric door closer is improved in a breakthrough manner, a complex structure which is commonly used in the normally open type fireproof door electric door closer and comprises a push-pull telescopic electromagnet, a push-pull mechanism and other material components is not used, a permanent magnet is fixed in a locking groove of a sliding block, the permanent magnet on the sliding block acts with a sucker type electromagnet fixedly arranged on a rotating block, the electromagnet is not electrified in a door opening state, and the limit locking of the sliding block is realized by means of the attraction of the permanent magnet and the end part of an electromagnet iron core in the locking groove, namely, when the normally open door state is maintained, the electromagnet does not need to be supplied with power, electric energy is effectively saved, and the permanent magnet and the electromagnet which is not electrified are automatically attracted and locked when the door is opened in place, and the limit is effective without manual reset, so that the use is convenient;

the invention also improves the structure of the unloading force retaining mechanism, designs kidney-shaped holes, circular arc grooves, balls, unloading force springs and other structures, when the door is forced to be closed, the right inclined surface of the locking groove of the sliding block forcedly pushes the rotating block, so that the right side of the rotating block moves upwards and rotates anticlockwise around the fixed pin;

compared with the existing limit unlocking assembly with the push-pull electromagnet, the integral structure of the magnetic limit unlocking assembly provided by the invention has the advantages that the structure is greatly simplified, the structure is simple, the used parts are obviously reduced, only one pin shaft and one rotating piece are provided, the production cost is effectively reduced, and the installation and the maintenance are more convenient.

Drawings

FIG. 1 is an isometric view of a magnetic type limit unlocking assembly provided by the invention;

FIG. 2 is a top view of the magnetically attractable limit unlocking assembly of FIG. 1;

FIG. 3 is a cross-sectional view of the magnetically attractable limit unlocking assembly of FIG. 2 taken along line A-A;

FIG. 4 is a front view of the magnetically attractable limit unlocking assembly of FIG. 1;

FIG. 5 is a cross-sectional view of the magnetically attractable limit unlocking assembly of FIG. 4 taken along line B-B;

FIG. 6 is an exploded view of the magnetically attractable limit unlocking assembly of FIG. 1;

FIG. 7 is an assembly view of the rotating block, stationary pin, electromagnet and unloading spring of FIG. 6;

FIG. 8 is a cross-sectional view of the magnetically attractable check lock release assembly of FIG. 1 in an unlocked position after being installed in a chute of an electric door closer;

FIG. 9 is a cross-sectional view of the magnetically attractable, limited release assembly of FIG. 1 in an attraction lock condition after being installed in a chute of an electric door closer;

fig. 10 is a view showing an electric door closer provided by the invention, wherein a magnetic-type limiting unlocking component shown in fig. 1 is installed in a chute of the electric door closer.

Fig. 11 is a schematic view of the electric door closer of fig. 10 after being mounted on a door frame and a door leaf.

In the drawings, the list of components represented by the various numbers is as follows:

1. a limit bracket; 2. a rotating block; 3. a permanent magnet; 4. a limiting end head; 5. a limit groove; 6. an electromagnet; 7. an arc groove; 8. a force-unloading spring; 9. a ball; 10. a slide block; 11. a locking groove; 12. a groove; 13. a slope surface; 14. a fixed pin shaft; 15. a through hole; 16. waist-shaped holes; 17. positioning columns; 18. limit raised strips; 19. a barrier strip; 20. a chute; 21. a control circuit board; 22. a mounting groove; 23. loading into a groove; 24. and a wire through hole.

Detailed Description

The principles and features of the present invention are described below with reference to the drawings and specific embodiments, the examples being provided for illustration only and not for the purpose of limiting the invention.

In the description of the present invention, if terms indicating orientations such as "upper", "lower", "left", "right", "top", "bottom", "inner", "outer", etc. are used, the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the indicated devices or elements must have a specific orientation, be configured and operated in the specific orientation, and thus are not to be construed as limiting the present invention.

As shown in fig. 1 to 7, the invention provides a magnetic attraction type limiting unlocking assembly, which comprises a limiting bracket 1, a rotating block 2, a permanent magnet 3 and a force-unloading retaining mechanism, wherein the rotating block 2 is pivoted in the inner cavity of the limiting bracket 1 through the middle part, a left-side lower part of the rotating block 2 is provided with a left-protruding limiting end head 4, the left wall of the inner cavity of the limiting bracket 1 is provided with a limiting groove 5 matched with the limiting end head 4, the right side of the rotating block 2 is fixedly provided with an electromagnet 6, the top surface of the rotating block 2 is provided with an arc groove 7, the force-unloading retaining mechanism comprises a force-unloading spring 8 and a ball 9, the top end of the force-unloading spring 8 is vertically arranged and is abutted against the top wall of the inner cavity of the limiting bracket 1, the ball 9 is pressed in the arc groove 7, the permanent magnet 3 is fixedly arranged on the top surface of a door closer slide 10, a locking groove 11 matched with the right-side lower part of the rotating block 2 is formed on the top surface of the slide 10, the electromagnet 6 and the permanent magnet 3 are fixedly connected with the locking groove 11 in a suction or repulsive mode when the rotating block 2 is in a position corresponding to the middle part or is pivoted around the rotation position of the slide 10.

The ball can be a steel ball or a plastic ball which is made of wear-resistant hard plastic and has a smooth surface; the spacing end is the protruding head (sheet-like) that stretches into in the spacing groove, and when the rotating block reciprocated and rotated, this protruding head can be at spacing inslot activity from top to bottom, and protruding head and spacing groove upper wall laminating top are tight (as shown in fig. 3 and 9) when permanent magnet and electro-magnet are inhaled, and when electro-magnet is after circular telegram with the permanent magnet repulsion and unblock, and the slider removes the back from the rotating block below, and the rotating block rotates to protruding head and spacing groove lower wall top to left under the effect of unloading the power spring (as shown in fig. 8). The permanent magnet can be a round cake with a hole in the center or the like, the permanent magnet is fixed on the sliding block through a bolt passing through the center of the permanent magnet, and a counter bore for installing the bolt is formed in the sliding block. In order to avoid the damage of the permanent magnet, a protective coating or a plastic protective sleeve can be arranged on the surface of the permanent magnet.

In one embodiment of the present invention, the permanent magnet 3 is fixed in a groove 12 formed on the top surface of the slider 10, the upper surface of the permanent magnet 3 is inclined to be higher and lower in the left and right directions and forms the bottom surface of the locking groove 11, and the right side groove wall of the locking groove 11 is provided with a slope surface 13 for interacting with the lower right corner of the rotating block 2. The setting of the locking groove is equivalent to the setting of a hook structure which is hung with the rotating block in the limiting bracket on the upper surface of the sliding block, and the setting of the locking groove is equivalent to the hanging of the hook structure and the rotating block during the attracting limiting. In the use state, as shown in fig. 3, the whole slide block is in a horizontal state, the right side of the locking groove on the upper surface is deep, the left side is shallow, the slide block is just matched with the inclined lower surface of the rotating block which rotates by an angle downwards to the right under the action of magnetic attraction, and the lower end surface of the electromagnet is well attached to the upper surface of the permanent magnet forming the bottom surface of the locking groove during attraction.

In one embodiment of the present invention, as shown in fig. 1, 3 and 6, the limiting bracket 1 is a cuboid block, the inner cavity of the limiting bracket 1 is a square groove disposed in the middle of the cuboid block and having a downward opening, both the left and right ends of the limiting bracket 1 are respectively provided with a fixing hole for connecting a locking bolt, the front and rear side walls of the square groove are correspondingly provided with a through hole 15 through which a fixing pin 14 penetrates, the rotating block 2 is provided with a kidney-shaped hole 16 through which the fixing pin 14 penetrates, the rotating block 2 is pivoted with the limiting bracket 1 through the kidney-shaped hole 16 and the fixing pin 14, the electromagnet 6 abuts against the upper edge of the kidney-shaped hole 16 after the permanent magnet 3 is locked or is repelled, and when the sliding block 10 pushes the rotating block 2 to the left to forcibly unlock, the rotating block 2 moves upward and rotates counterclockwise by an angle relative to the fixing pin 14.

The fixed pin shaft is a round shaft, the outer diameter of the fixed pin shaft is equal to the short shaft length of the kidney-shaped hole (clearance fit), and two ends of the fixed pin shaft are respectively positioned in through holes on the front side wall and the rear side wall of the limiting bracket.

In one embodiment of the present invention, as shown in fig. 8, after the electromagnet 6 and the permanent magnet 3 repel and unlock, the rotating block 2 just rotates to a horizontal state, and at this time, the kidney-shaped hole coincides with the central axis of the fixed pin in the vertical direction or shares the same symmetry plane in the vertical direction, that is, at this time, the ball 9 is pressed against the lowest point of the circular arc groove 7, and the vertical central axis of the ball 9 is located at the left side of the vertical line where the long axis of the kidney-shaped hole 16 is located, and the distance between the vertical central axis and the long axis is 3-10mm, as can be seen from the marked line change of the vertical central axis in fig. 8 and 9, when the complete unlocking is locked with respect to the actuation, the distance between the vertical central axis of the ball 9 and the fixed pin is slightly far, which indicates that the ball is pressed against the left side of the circular arc groove of the rotating block and slightly displaces to the right during the actuation locking.

In one embodiment of the invention, the top wall of the square groove is provided with a positioning column 17 protruding downwards, and the upper end of the force unloading spring 8 is sleeved on the positioning column 17 and abuts against the top wall of the square groove. The upper end of the force unloading spring can be only abutted against the top wall of the square groove and is not fixed, the lower end of the force unloading spring is sleeved on the ball, the lower end of the force unloading spring is ground flat, the inner diameter of an opening at the lower end is obviously smaller than the diameter of the ball (ball), the ball can be clamped at the lower end of the force unloading spring or the ball is pressed at the lower end of the force unloading spring and can roll relatively to the force unloading spring, a platform surface is arranged at the left side peripheral edge of the circular arc groove, and when the force is absorbed and locked, the lower end face of the force unloading spring can be pressed with the platform surface.

In one embodiment of the present invention, two limiting ribs 18 are disposed at the lower edge of the left side wall of the square groove at intervals up and down, the limiting groove 5 is formed between the two limiting ribs 18, the limiting end 4 abuts against the limiting rib 18 above after the electromagnet 6 and the permanent magnet 3 are in attraction locking, and the limiting end 4 abuts against the limiting rib 18 below after the electromagnet 6 and the permanent magnet 3 are in repulsion unlocking.

In one embodiment of the present invention, the lower surface of the right side of the cuboid block is provided with a stop bar 19 protruding downwards, the stop bar 19 extends into a notch on the lower surface of the sliding groove 20 of the door closer and is adapted to the width of the notch, the adaptation means that the stop bar is slightly narrower than the width of the notch, the stop bar can play a certain guiding role when the limit bracket is initially installed in the sliding groove, and even if the size of the limit bracket in the front-rear direction is much smaller than the corresponding size of the inner cavity of the sliding groove, the installation of the limit bracket can be completed under the cooperation of the stop bar and the notch. After the electromagnet 6 is in attraction and locking with the permanent magnet 3, the right end of the sliding block 10 is just abutted against the left end face of the stop strip 19. The left end of the barrier strip is a limiting part for opening the door in place, when the door is opened to the maximum position, the right end of the sliding block is abutted against the left end of the barrier strip, and at the moment, the permanent magnet is just attracted with the lower end face of the non-electrified electromagnet.

In one embodiment of the present invention, the electromagnet 6 is a circular or rectangular sucker type electromagnet, and a control circuit board 21 electrically connected to the electromagnet 6 is further disposed in the limit bracket 1. It should be noted that the electromagnet in the invention is provided with a fixed iron core, and when the electromagnet is not electrified, the iron core is non-magnetic and plays a role of attracting with the permanent magnet; when the permanent magnet is electrified, the iron core generates magnetism, and the magnetic pole at the lower end of the iron core is opposite to the magnetic pole on the upper surface of the permanent magnet, so that repulsion is generated.

In one embodiment of the present invention, a mounting groove 22 with a downward opening for mounting the electromagnet 6 is provided on the right side of the rotating block 2, a mounting groove 23 for mounting the control circuit board 21 is provided on the right side of the limiting bracket 1, and a wire passing hole 24 communicating with the mounting groove 23 is provided on the right side wall of the inner cavity of the limiting bracket 1.

The invention also provides an electric door closer, as shown in fig. 8-10, which comprises the magnetic limiting unlocking component. When the electric fireproof door closer is installed on a door frame and a door leaf, as shown in fig. 11, the electric fireproof door closer mainly comprises five parts, namely, A, a fireproof door leaf, B, a fireproof door frame, C, a fireproof door linkage chute (namely, a door closer chute 20), D, a door opening and closing execution connecting rod and E, and a hydraulic device, wherein the magnetic type limiting unlocking component and the electronic device with the signal detection and feedback functions are arranged in the C fireproof door linkage chute, so that the door closer can be remotely controlled to act, and the fireproof door can be timely closed when a fire disaster occurs. The opening and closing of the fireproof door mainly utilizes the hydraulic device to provide power to drive the connecting rod to move, so that the driving sliding block slides in the opening track (notch) along the sliding groove, and further the opening and closing of the fireproof door leaf are controlled. Considering when the conflagration takes place, prevent fire door needs quick stable closing, so the structure that restricts the slider motion needs to satisfy can be to the spacing locking of slider, can unblock release slider motion along the spout again to prevent fire door.

In the invention, the electromagnet 6 is fixed in the mounting groove 22 of the rotating block 2, the two are integrated, when the fireproof door is opened to a designated position, the sliding block 10 slides to the position right below the magnetic-attraction type limiting unlocking component along the opening track of the sliding groove 20, when the sliding block 10 moves to the limit position of the limiting bracket 1 and can not move after being abutted against the stop bar 19, the permanent magnet 3 is contained in the sliding block 10, and the permanent magnet is magnetically attracted to the electromagnet at the right end of the rotating block 2, so that the rotating block 2 rotates clockwise along the fixed pin 8, the sliding block 10 and the electromagnet 6 are attracted mutually after approaching, thereby realizing the limiting locking of the sliding block 10, the limiting is completed by mechanical limiting, the limiting is not needed to be manually reset for limiting after the door is opened in place, the aim of automatic limiting after the door is opened, and the normally open door state is kept without consuming electric energy.

Principle and scheme of electric control door closing: when a fire disaster occurs, the remote control room sends a door closing command, the electromagnet 6 is electrified through the conversion function of the control circuit board 21, the electromagnet 6 generates a polarity of N on the lower end face of the electromagnet in the electrifying process, the end face of the permanent magnet attracted with the electromagnet is also the N pole, the permanent magnet and the electromagnet generate a pole effect of like poles repelling each other, the rotating block 2 is forced to rotate anticlockwise, and therefore limit is relieved, and the fireproof door is immediately closed under the action of the hydraulic device.

Principle and scheme of forced closing door: when a fire disaster occurs, a problem that an instruction of electric control door closing cannot be effectively transmitted to a door closer is caused sometimes due to a problem of line faults, the fire door is required to be closed manually in a forced mode, the magnetic limiting unlocking component is always in a suction state with the sliding block 10, the sliding block 10 is forced to move upwards by the action of external force in the horizontal direction, the rotating block 2 is forced to move upwards, the rotating block can move up and down relative to the fixed pin shaft because a waist hole is designed on the rotating block 2, the ball 9 pressed by the force unloading spring 8 is arranged in the circular arc groove 7 of the rotating block 2, when the ball 9 is pressed by the external force, the force unloading spring 8 is compressed, and the contact action point of the ball and the circular arc groove is also deviated from the lowest point due to the rotation action of the rotating block 20, the pressure action of the ball on the rotating block is increased, and the ball is directed to the left along the radial direction, so that the magnetic attraction action of the permanent magnet at the right end is relatively easier to be removed when the sliding block 10 is subjected to the action of the strong door closing external force, and the limiting is relieved, and the aim of forced door closing is achieved.

The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims (10)

1. The utility model provides a spacing unblock subassembly of magnetic attraction type, its characterized in that includes spacing support (1), rotating block (2), permanent magnet (3) and unloads the power and keep the mechanism, rotating block (2) through the middle part pin joint in spacing support (1) inner chamber, the left side lower part of rotating block (2) is equipped with left convex spacing end (4), spacing support (1) inner chamber left wall be equipped with spacing end (4) complex spacing groove (5), the right side of rotating block (2) is fixed with electro-magnet (6), the top surface of rotating block (2) is equipped with circular arc groove (7), it includes and unloads power spring (8) and ball (9) to unload power spring (8) vertical setting and top and spacing support (1) inner chamber roof supports tightly, the lower extreme of unloading power spring (8) will ball (9) compress tightly in circular arc groove (7), permanent magnet (3) are fixed to be located door closer slider (10) top surface and in slider (10) top surface form and are in the cooperation with electromagnet (11) is in the place of locking groove (11) when locking down, the rotating block (2) rotates around the middle pivot joint to correspondingly limit and lock or unlock the sliding block (10).

2. The magnetic limiting unlocking assembly according to claim 1, wherein the permanent magnet (3) is fixed in a groove (12) formed in the top surface of the sliding block (10), the upper surface of the permanent magnet (3) is inclined in a left-high-right low-inclination manner and forms the bottom surface of the locking groove (11), and the right side groove wall of the locking groove (11) is provided with a slope surface (13) for interacting with the right lower corner of the rotating block (2).

3. The magnetic type limiting unlocking assembly according to claim 1, wherein the limiting support (1) is a cuboid block, an inner cavity of the limiting support (1) is a square groove which is arranged in the middle of the cuboid block and is provided with a downward opening, fixing holes for connecting locking bolts are formed in the left end and the right end of the limiting support (1), through holes (15) for penetrating through fixing pins (14) are correspondingly formed in the front side wall and the rear side wall of the square groove, waist-shaped holes (16) for penetrating through the fixing pins (14) are formed in the rotating block (2) in the front-back mode, the rotating block (2) is pivoted with the limiting support (1) through the waist-shaped holes (16) and the fixing pins (14), after the electromagnet (6) and the permanent magnet (3) are in attraction locking or rejection unlocking is completed, the fixing pins (14) are abutted to the upper edges of the waist-shaped holes (16), and when the sliding block (10) pushes the rotating block (2) to the left side to push the rotating block to the left for unlocking, the rotating block (2) is relatively rotated by a anticlockwise angle.

4. A magnetic limiting unlocking assembly according to claim 3, wherein after the electromagnet (6) and the permanent magnet (3) repel and unlock, the rotating block (2) just rotates to a horizontal state, at this time, the balls (9) are pressed on the lowest point of the circular arc groove (7), the vertical central axis of the balls (9) is located on the left side of the vertical line where the long axis of the kidney-shaped hole (16) is located, and the distance between the vertical central axis and the long axis is 3-10mm.

5. A magnetic limiting unlocking assembly according to claim 3, wherein the top wall of the square groove is provided with a positioning column (17) protruding downwards, and the upper end of the force unloading spring (8) is sleeved on the positioning column (17) and is abutted against the top wall of the square groove.

6. A magnetic type limiting unlocking assembly according to claim 3, characterized in that two limiting raised strips (18) are arranged at the lower edge of the left side wall of the square groove at an upper-lower interval, the limiting groove (5) is formed between the two limiting raised strips (18), after the electromagnet (6) and the permanent magnet (3) are in attraction locking, the limiting end head (4) is abutted against the limiting raised strips (18) above, and after the electromagnet (6) and the permanent magnet (3) are in repulsion unlocking, the limiting end head (4) is abutted against the limiting raised strips (18) below.

7. A magnetic limiting unlocking assembly according to claim 3, wherein a blocking strip (19) protruding downwards is arranged on the lower surface of the right side of the cuboid block body, the blocking strip (19) stretches into a notch on the lower surface of a door closer sliding groove (20) and is adaptive to the width of the notch, and after the electromagnet (6) is in attraction locking with the permanent magnet (3), the right end of the sliding block (10) is just abutted to the left end face of the blocking strip (19).

8. A magnetic limiting unlocking assembly according to any one of claims 1 to 7, characterized in that the electromagnet (6) is a circular or rectangular sucker type electromagnet, and a control circuit board (21) electrically connected with the electromagnet (6) is further arranged in the limiting bracket (1).

9. The magnetic limiting unlocking assembly according to claim 8, wherein a mounting groove (22) with an opening downwards for the electromagnet (6) to be mounted is formed in the right side of the rotating block (2), a mounting groove (23) for the control circuit board (21) to be mounted is formed in the right side of the limiting support (1), and a wire passing hole (24) communicated with the mounting groove (23) is formed in the right side wall of an inner cavity of the limiting support (1).

10. An electric door closer comprising a magnetically attractable limit unlocking assembly according to any one of claims 1 to 9.