Automatically-closed door closer

Abstract

The invention discloses an automatic closing door closer which comprises a door closer body, an automatic closing device and an auxiliary closing device. The automatic closing device is connected with an output shaft on one side of the main body and comprises a mechanical locking mechanism composed of an angle cam, a sliding block and a supporting spring and a triggering mechanism composed of a swing connecting rod, an unlocking connecting rod and an electric driving mechanism with a gear motor, the output shaft is stably locked in a normally-open state, electric unlocking is achieved when fire signals are triggered, and the automatic closing device can automatically close the output shaft. And the door leaf is automatically closed by the door closer main body. The auxiliary closing device is connected with an output shaft on the other side of the main body and comprises a cam shaft with a concave part and a trigger assisting assembly composed of a roller, a piston and a pressure spring, and when the door leaf is closed to the angle smaller than the set angle, the roller falls into the concave part of the cam, and the pre-tightened spring elastic force is released to generate auxiliary torque. According to the fireproof door, the functions of normally-open locking and releasing and door closing tail section assisting are integrated, and the automatic closing reliability and the final leakproofness of the fireproof door in a fire disaster are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of door control hardware technology, and in particular to an automatic closing door closer. Background Technology

[0002] In modern building fire safety systems, normally open fire doors must automatically and reliably close to block smoke and fire in the event of a fire. While the widely used electromagnetic release devices and electric door closers can achieve automatic closing, they have significant shortcomings: the former requires continuous power to maintain its engaged state, resulting in high energy consumption and a risk of malfunction during power outages, and its long-term reliability is constrained by power supply stability; the latter, although capable of directly driving the door to close, has a complex structure, high cost, and continuous standby also leads to energy consumption and maintenance issues. Furthermore, under the positive pressure maintained by a mechanical pressurization system, fire doors face significant air resistance in the final stage of closing (usually less than 15 degrees). At this point, the closing torque provided by conventional door closers drops to its minimum, often failing to overcome this resistance, resulting in the door not closing completely and creating a smoke spread hazard. Existing solutions often rely on increasing the size of the door closer or adjusting the overall air pressure system, which suffers from poor adaptability, high retrofit costs, or complex system debugging. There is still a lack of an economical, reliable, and easy-to-implement overall solution that can simultaneously achieve normally open locking, automatic fire release, and auxiliary assistance in the final stage of closing. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an automatic closing door closer that can achieve reliable mechanical locking and low-power electric release in the normally open state, while intelligently providing auxiliary torque at the end of the closing process, thus comprehensively improving the automatic closing performance and sealing reliability of fire doors in emergency situations such as fires.

[0004] The technical solution adopted by this invention to solve its technical problem is: An automatically closing door closer, comprising: The door closer body is used to provide the main torque for driving the door to close; An automatic closing device is connected to the output shaft on one side of the door closer body. It is used to lock the output shaft when the door is normally open, and to release the lock through an electric drive mechanism when a fire signal is received, so that the door is automatically closed under the action of the door closer body. An auxiliary closing device is connected to the output shaft on the other side of the door closer body. The auxiliary closing device has a pre-tightened elastic element built in, which is used to release the elastic force of the elastic element when the door is closed to less than a set angle, so as to provide auxiliary torque to the output shaft.

[0005] An automatic closing door closer according to an embodiment of the present invention has at least the following beneficial effects: The core of the present invention lies in the creative integration of an automatic closing device and an auxiliary closing device into a traditional door closer, forming a fully functional intelligent door closing system. The automatic closing device keeps the fire door open through a robust mechanical locking mechanism, and is only triggered by a low-power electric mechanism in case of fire to release the energy stored in the door closer and complete the closing, achieving a highly reliable automatic fire response with zero standby energy consumption. At the same time, the auxiliary closing device can intelligently sense the closing angle and automatically provide additional assistance in the final stage when the closing torque is weakest, effectively overcoming resistance such as positive pressure environment and ensuring that the door leaf is tightly closed. The two devices work together to provide precise and reliable solutions for the two key aspects of "keeping open - closing in case of fire" and "ensuring tight closure". Structurally, they do not interfere with each other and are easy to integrate and install, fundamentally improving the overall safety, economy and applicability of the fire door system.

[0006] According to some embodiments of the present invention, the automatic closing device includes a first housing having a first sliding cavity, a first rotating cavity, and a control cavity inside; an angle cam rotatably disposed in the first rotating cavity, having a first recess on its circumferential surface; the angle cam being connected to a support arm for docking with the output shaft of the door closer body, and the relative angle between the support arm and the angle cam being adjustable; a slider slidably disposed in the first sliding cavity, having a first roller at one end; and a support spring acting on the slider to provide a preload force to the first roller toward the angle cam; in the normally open state of the door, the first roller engages with the first recess to lock the angle cam.

[0007] The advantages are: the mechanical cooperation between the angle cam and the slider achieves a stable self-locking of the door closer's output shaft, resulting in a simple and reliable structure that can maintain a normally open and locked state even in a passive condition. The adjustable-angle support arm enhances the device's adaptability to different installation environments and door closer models, facilitating on-site installation and commissioning.

[0008] According to some embodiments of the present invention, the automatic closing device further includes a triggering mechanism disposed in the control cavity. The triggering mechanism includes a swing link and an unlocking link. The swing link is inverted T-shaped, with its vertical side rotatably connected to the first housing and a card interface at one end of its horizontal side. The unlocking link is inverted Z-shaped, with its middle part rotatably connected to the first housing and a docking part that mates with the card interface at one end. In the locked state, the docking part engages with the card interface to fix the swing link.

[0009] The advantages are that the inverted T-shaped and inverted Z-shaped linkage design results in a compact structure, a reasonable lever arm, and efficient and reliable motion transmission. This mechanical interlocking method ensures the stability of the locked state, prevents accidental unlocking due to vibration or other factors, and provides a clear action interface for electric drive.

[0010] According to some embodiments of the present invention, the electric drive mechanism includes a geared motor electrically connected to a fire warning system and a release cam driven by the geared motor, for driving the release cam to push the unlocking linkage when a fire signal is received, so that the docking part disengages from the card interface.

[0011] The advantages are that the drive system, which combines a geared motor with a release cam, enables precise and reliable mechanical unlocking with low power consumption and torque requirements. This design offers rapid response and integrates with fire suppression systems, ensuring timely and automatic door unlocking in the event of a fire.

[0012] According to some embodiments of the present invention, a first reset assembly is provided between the support spring and the swing link. The first reset assembly includes a first support link and a second support link, which are hinged together by a movable shaft and jointly support the bottom of the support spring. The other end of the first support link is hinged to the first housing by a fixed shaft, and the other end of the second support link is hinged to the swing link. A torsion spring acting between the slider and the inner wall of the first housing is provided on the fixed shaft.

[0013] The advantage is that the first reset component not only provides floating support for the support spring, but more importantly, through the combination of the linkage and the torsion spring, it can effectively convert the force of the door closer's rotation into the reset power of the entire trigger mechanism when the door is reopened, realizing the automatic reset of the device after the door closing action, improving the convenience of use and the efficiency of cyclic operation.

[0014] According to some embodiments of the present invention, the unlocking link is provided with a second reset component, which is a reset spring acting on the unlocking link, for resetting the unlocking link after the release cam is reset.

[0015] The advantage is that the return spring installed on the unlocking linkage can provide a reliable automatic rebound force to the unlocking linkage after the gear motor drives the release cam to reset, so that it can quickly and accurately return to the initial ready position. This ensures that the triggering mechanism can be ready for the next locking immediately after one action, thus enhancing the reliability and response speed of the system.

[0016] According to some embodiments of the present invention, the first housing is further provided with a PCB circuit board electrically connected to the gear motor and a PCB cover plate for covering the PCB circuit board. The PCB cover plate is provided with an indicator light. The first housing is provided with a reset button electrically connected to the PCB circuit board for controlling the release cam to reset.

[0017] The advantages are: the integrated PCB circuit board enables centralized and intelligent electrical control, and the indicator lights provide intuitive indications of the working status, facilitating user monitoring. The reset button provides a convenient means of manual restoration after on-site debugging, testing, or malfunction, greatly enhancing product maintainability and user experience.

[0018] According to some embodiments of the present invention, the auxiliary closing device includes a second housing having a second rotating cavity and a second sliding cavity communicating with the second rotating cavity; a camshaft rotatably disposed in the second rotating cavity, having a second recess on the circumferential surface of its cam portion, and its pivot portion extending out of the second housing and linked with the output shaft of the door closer body; and a trigger assist assembly disposed in the second sliding cavity, including a second roller, a piston, and a pressure spring as the elastic element; the second roller abuts against the circumferential surface of the cam portion, and the pressure spring acts on the piston and provides it with a preload force toward the cam portion.

[0019] The advantages are: this structure achieves precise monitoring of the closing angle through the mechanical sensing of the cam and roller. The pressure spring is pre-stored with energy and is only released at a specific angle at the end of the closing process by the roller falling into the recess, converting the elastic force into effective auxiliary torque. This provides precise assistance, and the entire process is purely mechanical, requiring no external energy source, making it reliable and durable.

[0020] According to some embodiments of the present invention, an end cap is provided at one end of the second sliding cavity away from the second rotating cavity, the end cap is threadedly connected to the second sliding cavity, one end of the pressure spring acts on the piston, and the other end acts on the inner side of the end cap, and an adjustment hole is provided on the outer end face of the end cap.

[0021] The advantages are that the threaded end cap design not only facilitates the assembly and internal maintenance of the device, but more importantly, the pre-compression of the pressure spring can be conveniently and continuously adjusted by rotating the end cap, thereby flexibly changing the magnitude of the auxiliary torque. This allows the device to easily adapt to the needs of different door weights and different usage environments, making it highly versatile.

[0022] According to some embodiments of the present invention, the pressure spring includes a first spring and a second spring coaxially sleeved, wherein the first spring and the second spring have opposite directions of rotation.

[0023] The advantages are: the design of double springs with opposite rotation directions can provide greater or more linear elastic force in a limited space, enhancing the assist effect; on the other hand, the opposite rotation direction can effectively counteract the radial torque generated when the spring is working, making the spring assembly work more stably and the force line more concentrated, reducing unnecessary friction and wear, improving the smoothness of the assist output and the service life of the device.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is an installation diagram of an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram showing the automatic closing device disassembled from the front; Figure 3 for Figure 1 A schematic diagram of the internal structure of the automatic closing device after disassembly at the back; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 for Figure 1 Exploded view of the automatic closing device in the middle; Figure 6 for Figure 1 Internal schematic diagram of the auxiliary closing device.

[0027] Reference numerals: Door closer body 100, Automatic closing device 110, Auxiliary closing device 120, Elastic element 130, First housing 140, First sliding cavity 150, First rotating cavity 160, Control cavity 170, Angle cam 180, First recess 190, Support arm 200, Slider 210, First roller 220, Support spring 230, Swing link 240, Unlocking link 250, Card interface 260, Connecting part 270, Gear motor 280, Release cam 290, First support link 3 00, Second support link 310, Movable shaft 320, Fixed shaft 330, Torsion spring 340, Return spring 350, PCB circuit board 360, PCB cover plate 370, Indicator light 380, Reset button 390, Second housing 400, Second rotating cavity 410, Second sliding cavity 420, Cam shaft 430, Cam part 440, Second recess 450, Rotating shaft part 460, Second roller 470, Piston 480, End cover 490, Adjustment hole 500, First spring 510, Second spring 520. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0029] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0030] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" and "second" are mentioned, this is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation, connection, and linkage" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] The following is for reference. Figures 1-6 An automatically closing door closer is described in detail with reference to a specific embodiment. It is to be understood that the following description is merely illustrative and not intended to limit the invention.

[0033] like Figure 1 As shown, an automatic closing door closer integrates a set of automatic closing devices 110 specifically designed for normally open fire doors and an auxiliary closing device 120 for enhancing the closing effect, all within a conventional door closer body 100. The door closer body 100 provides the main torque for driving the door to close and is the fundamental power source for the entire system.

[0034] like Figures 2-5As shown, the automatic closing device 110 is connected to the output shaft on one side of the door closer body 100, and it incorporates a sophisticated mechanical locking and electric triggering system. The device includes a first housing 140, which is divided into a first sliding cavity 150, a first rotating cavity 160, and a control cavity 170. Within the first rotating cavity 160, an angle cam 180 is rotatably mounted via bearings. A specific first recess 190 is machined on the circumferential surface of the angle cam 180, and one end face of the cam is connected to a support arm 200 via a cam connector and connecting bolts. This adjustable connection allows for flexible adjustment of the initial installation angle of the support arm 200 relative to the angle cam 180, thereby greatly improving the device's adaptability to different installation positions and different door closer models. The support arm 200 is used to securely engage with the output shaft of the door closer body 100. Within the first sliding cavity 150, a slider 210 that can slide along its axis is provided, and a first roller 220 is mounted on the end of the slider 210 facing the angle cam 180. A support spring 230 acts on the slider 210, providing it with a preload force that keeps the first roller 220 pressed firmly against the circumferential surface of the angle cam 180. When the fire door needs to remain open, the door is manually opened to a predetermined position. At this time, the rotation of the output shaft of the door closer body 100 will drive the angle cam 180 to rotate through the support arm 200 until the first roller 220 is precisely engaged into the first recess 190 of the angle cam 180 under the push of the support spring 230. This engagement between the roller and the recess forms a stable mechanical self-locking mechanism, like a mechanical "buckle," firmly locking the angle cam 180 and its connected output shaft, allowing the door to remain stably open. This process is achieved entirely by mechanical structure, without consuming any electrical energy, and the locking is reliable and durable.

[0035] To ensure stable maintenance of the locked state and reliable release in case of fire, the automatic closing device 110 is also equipped with a triggering mechanism and an electric drive mechanism. For example... Figures 4-5As shown, the triggering mechanism is located within the control cavity 170, and its core consists of two cooperating links: a swing link 240 and an unlocking link 250. The swing link 240 is designed in an inverted T-shape, with its vertical side serving as a pivot hinged to the first housing 140, forming a rotation fulcrum. One end of its horizontal side is indirectly connected to the bottom of the support spring 230 via a complex first reset assembly, while the other end has a square notch machined as a locking interface 260. The first reset assembly is formed by hinged first support link 300 and second support link 310 via a movable shaft 320, together forming a floating "V"-shaped bracket that supports the bottom of the support spring 230. The other end of the first support link 300 is hinged to the first housing 140 via a fixed shaft 330, and the other end of the second support link 310 is hinged to the horizontal side of the swing link 240. Specifically, a torsion spring 340 is fitted onto the fixed shaft 330, with its two ends acting on the inner walls of the slider 210 and the first housing 140, respectively. This design gives the entire mechanism the function of automatic reset after unlocking. The unlocking link 250 is designed in an inverted Z-shape, with its central turning point hinged to the first housing 140. One end of the unlocking link 250 extends to the vicinity of the swing link 240 and has a block serving as a docking part 270. In the locked state where the door is normally open, this block precisely engages with the locking interface 260 of the swing link 240, thereby fixing the swing link 240 in place and indirectly maintaining the locked state of the first roller 220 engaged with the first recess 190. Above the hinge point of the unlocking link 250, a second reset component—a reset spring 350—is also provided, which abuts against the unlocking link 250 and provides it with a restoring force. The electric drive mechanism is also located within the control cavity 170, including a gear motor 280 electrically connected to the fire alarm system, and a release cam 290 fixed to the output shaft of the motor. The gear motor 280 is controlled by a PCB circuit board 360 integrated on the first housing 140, which is covered by a PCB cover plate 370 with an indicator light 380 for status indication. A reset button 390 connected to the PCB circuit board 360 is also located on the outside of the first housing 140. In the normally open state, the entire mechanical system is in a balanced locked state. When a fire alarm signal is received, the PCB circuit board 360 controls the gear motor 280 to start instantaneously, driving the release cam 290 to rotate. The protruding part of the release cam 290 pushes the inverted Z-shaped unlocking linkage 250 to rotate around its hinge point, causing the square block at its front end to disengage from the square notch of the swing linkage 240. Once released, the swing linkage 240 changes the mechanical balance applied to the support spring 230 and the slider 210. At this moment, the enormous elastic potential energy stored in the main spring inside the door closer body 100 begins to be released, driving its output shaft to attempt to rotate and close. The output shaft drives the angle cam 180 to rotate via the support arm 200, and the contour of the first recess 190 of the angle cam 180 pushes the first roller 220, which was originally stuck in it, outward.The first roller 220 pushes the slider 210 to compress the support spring 230, completely disengaging it from the recess. At this point, the mechanical lock is completely released, and the fire door automatically closes smoothly, quickly, and reliably under the powerful torque of the door closer body 100. When the door needs to be reset to normally open after a fire, simply press the reset button 390 to reverse the motor, causing the release cam 290 to return to its original position. Then, manually open the door. During this process, the rotation of the door closer's output shaft automatically drives the swing linkage 240 to reset through the linkage of the angle cam 180, slider 210, support spring 230, and the first reset assembly. Simultaneously, the reset spring 350 pushes the unlocking linkage 250 back to its original position, causing the block to realign with the card interface 260, and the entire device returns to a ready-to-trigger state.

[0036] Meanwhile, the auxiliary closing device 120, integrated on the output shaft on the other side of the door closer body 100, focuses on solving the problem of insufficient force at the end of the closing process. For example... Figure 6As shown, the device includes a separate second housing 400, the interior of which is divided into a second rotating cavity 410 and a second sliding cavity 420 communicating with it. Inside the second rotating cavity 410, a camshaft 430 is rotatably mounted via bearings, its shaft portion 460 extending out of the second housing 400 and synchronously linked with the output shaft of the door closer body 100 via a structure such as a square sleeve. A second recess 450 is machined on the circumferential surface of the cam portion 440 of the camshaft 430, the mating surface of which is preferably arc-shaped. Inside the second sliding cavity 420, a trigger assist assembly is provided, which sequentially includes a second roller 470, a piston 480, and a pressure spring as the core elastic element 130 along the axial direction. The piston 480 is slidably mounted inside the cavity, and the second roller 470 is rotatably mounted on one end of the piston 480 via a pin, allowing it to maintain constant contact with the circumferential surface of the cam portion 440 through rolling friction, effectively reducing wear. A pressure spring acts on the other end of the piston 480, providing it with a preload that always points towards the cam portion 440. As an optimization, this pressure spring can be a combination of a first spring 510 and a second spring 520 coaxially fitted and rotating in opposite directions to provide better elasticity and stability within a limited space. The end of the second sliding cavity 420 is closed by a threaded end cap 490 with an adjustment hole 500, and the other end of the pressure spring rests against the inside of the end cap 490. By rotating the end cap 490 with a tool, the preload of the pressure spring can be easily adjusted, thereby changing the magnitude of the auxiliary torque to adapt to different door weights or environmental resistance. During most of the closing process, i.e., when the door closing angle is greater than a set threshold (e.g., 15 degrees), the second roller 470 continuously rolls on the outer edge of the circumferential surface of the cam portion 440, continuously compressing the pressure spring and storing energy. When the door rotates to the final closing stage, when the angle is less than the set threshold, the second recess 450 on the cam portion 440 rotates precisely to the position corresponding to the second roller 470. At this moment, the elastic potential energy stored in the compressed spring is released instantaneously, pushing the piston 480 and causing the second roller 470 to fall into the second recess 450. The second roller 470 applies a force to the arc-shaped sidewall of the second recess 450. After the force is decomposed, it generates a significant additional torque that drives the camshaft 430 (i.e., the door closer output shaft) to continue rotating. This torque, combined with the main torque of the door closer body 100 itself, forms a strong "final push" at the weakest moment of closing, thereby ensuring that the door can overcome the friction of the lintel sealing strip, the resistance of positive air pressure, and other interferences, achieving a tight and reliable final closure and eliminating the hidden danger of gaps caused by incomplete closing.

[0037] In summary, the working process of the automatic door closer of this invention can be summarized as follows: Normally, the door is reliably locked in the normally open state by the mechanical mechanism of the automatic closing device 110; in case of fire, the electric mechanism receives a signal and is triggered, releasing the mechanical lock, and the door closer body 100 releases its stored energy to drive the door to close automatically; in the final stage of closing, the auxiliary closing device 120 senses the closing angle and automatically releases its stored spring force, providing additional auxiliary torque to ensure the door is tightly closed. The beneficial effects of this invention are concentrated in: creatively integrating the two major functions of "normally open locking - fire release" and "final stage assistance" into modular units, providing a complete solution. Its automatic closing part achieves high-reliability fire linkage with zero standby energy consumption, has an ingenious structure, and possesses an automatic reset function; the auxiliary closing part intelligently enhances the final stage closing force in a purely mechanical manner, with precise response and adjustable assistance. The entire system requires no complex modifications to the existing building's air pressure system or the main body of the door closer 100. It is easy to install and simple to maintain. In an economical, efficient and reliable manner, it fundamentally solves the industry pain points of normally open fire doors in terms of automatic closing reliability and final sealing, and significantly improves the overall level of building fire safety.

[0038] In the description of this specification, the references to terms such as "an embodiment, some embodiments, illustrative embodiments, example, specific example, or examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0039] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An automatic closing door closer characterised in that, The application relates to a door closer, which comprises: a door closer body (100) for providing a main torque for driving a door leaf to close; an automatic closing device (110) connected with an output shaft of one side of the door closer body (100), which is used for locking the output shaft in a normal open state of the door leaf and releasing the locking through an electric drive mechanism to make the door leaf automatically close under the action of the door closer body (100) when a fire signal is received; an auxiliary closing device (120) connected with an output shaft of the other side of the door closer body (100), which is internally provided with a pre-tightened elastic element (130) for releasing the elastic force of the elastic element (130) when the door leaf is closed to less than a set angle to provide an auxiliary torque to the output shaft.

2. The self-closing door closer of claim 1, wherein The automatic closing device (110) comprises a first machine shell (140) internally provided with a first sliding cavity (150), a first rotating cavity (160) and a control cavity (170); an angle cam (180) rotatably arranged in the first rotating cavity (160) and provided with a first recess (190) on a circumferential surface; a support arm (200) connected with the angle cam (180) and used for butting against the output shaft of the door closer body (100), and the relative angle between the support arm (200) and the angle cam (180) is adjustable; a sliding block (210) slidably arranged in the first sliding cavity (150) and provided with a first roller (220) at one end; and a support spring (230) acting on the sliding block (210) and providing a pre-tightening force of the first roller (220) towards the angle cam (180); in the normal open state of the door leaf, the first roller (220) is clamped into the first recess (190) to lock the angle cam (180).

3. A self-closing door closer according to claim 2, wherein The automatic closing device (110) further comprises a trigger mechanism arranged in the control cavity (170), which comprises a swing link (240) and an unlocking link (250); the swing link (240) is inverted T-shaped, the vertical edge of which is rotatably connected with the first machine shell (140), and the horizontal edge of which is provided with a clamping interface (260) at one end; the unlocking link (250) is inverted Z-shaped, the middle part of which is rotatably connected with the first machine shell (140), and one end of which is provided with a butt joint part (270) matched with the clamping interface (260); in the locking state, the butt joint part (270) is clamped with the clamping interface (260) to fix the swing link (240).

4. A self-closing door closer according to claim 3, wherein The electric drive mechanism comprises a gear motor (280) electrically connected with a fire warning system and a release cam (290) driven by the gear motor (280), which is used for driving the release cam (290) to push the unlocking link (250) to make the butt joint part (270) disengage from the clamping interface (260) when a fire signal is received.

5. A self-closing door closer according to claim 4, wherein A first reset assembly is arranged between the support spring (230) and the swing link (240), and comprises a first support link (300) and a second support link (310), which are hingedly connected by a movable shaft (320) and jointly support the bottom of the support spring (230); the other end of the first support link (300) is hingedly connected to the first casing (140) by a fixed shaft (330), and the other end of the second support link (310) is hingedly connected to the swing link (240); the fixed shaft (330) is provided with a torsion spring (340) acting between the slider (210) and the inner wall of the first casing (140).

6. A self-closing door closer according to claim 5, wherein A second reset assembly is arranged on the unlocking link (250), and is a reset spring (350) acting on the unlocking link (250) to reset the unlocking link (250) after the release cam (290) is reset.

7. The self-closing door closer of claim 4, wherein The first casing (140) is further provided with a PCB circuit board (360) electrically connected to the gear motor (280), and a PCB cover plate (370) for covering the PCB circuit board (360), the PCB cover plate (370) is provided with a display lamp (380), and the first casing (140) is provided with a reset button (390) electrically connected to the PCB circuit board (360) to control the reset of the release cam (290).

8. The self-closing door closer of claim 1, wherein The auxiliary closing device (120) comprises a second casing (400), which is internally provided with a second rotating cavity (410) and a second sliding cavity (420) in communication with the second rotating cavity (410); a camshaft (430) is rotatably arranged in the second rotating cavity (410), the cam portion (440) of the camshaft (430) is provided with a second recess (450) on the circumferential surface thereof, the shaft portion (460) of the camshaft (430) extends out of the second casing (400) and is connected with the output shaft of the door closer main body (100); and a trigger assisting assembly is arranged in the second sliding cavity (420) and comprises a second roller (470), a piston (480) and a pressure spring as the elastic element (130); the second roller (470) abuts against the circumferential surface of the cam portion (440), and the pressure spring acts on the piston (480) and provides a pre-tightening force to the piston (480) towards the cam portion (440).

9. A self-closing door closer according to claim 8, wherein One end of the second sliding cavity (420) away from the second rotating cavity (410) is provided with an end cover (490), the end cover (490) is threadedly connected with the second sliding cavity (420), one end of the pressure spring acts on the piston (480), and the other end of the pressure spring acts on the inner side of the end cover (490), and the outer end surface of the end cover (490) is provided with an adjusting hole (500).

10. The self-closing door closer of claim 8, wherein, The pressure spring comprises a first spring (510) and a second spring (520) coaxially sleeved, and the rotation directions of the first spring (510) and the second spring (520) are opposite.

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