An automatic door closer

Abstract

This invention relates to the field of timed door closing technology, specifically to an automatic door closer. An automatic door closer includes a housing, a transmission gear, a door hinge, and a piston. The transmission gear and piston are installed inside the housing. A connecting shaft is located in the middle of the transmission gear. One end of the connecting shaft is fixed to the transmission gear, and the other end extends out of the housing and connects to the door hinge. The door hinge is also connected to the door. When the door rotates, it drives the door hinge to rotate, which in turn drives the transmission gear to rotate. This invention is ingeniously designed and structurally sound, effectively solving the problem of building doors failing to close automatically in existing technologies, and is suitable for widespread application.

Description

Technical Field

[0001] The invention relates to the technical field of timed door closing, and in particular to an automatic door closer. Background Art

[0002] After careful observation, the inventor discovered a problem with potential safety hazards that is widely present in life, that is, the traditional door of a unit building or a unit factory building, due to the relatively traditional mechanical structure used for rotation, such as the use of simple mechanical structures such as springs, can close automatically when the door is pushed no more than 70 degrees, but in cases where it takes longer to pass through, such as moving furniture, it is necessary to push the door to more than 90 degrees, or even stick the door to the wall, so as not to hinder passage, but generally after the work is done, few people close the door manually. In this case, since it exceeds 90°, the door will not close by itself, which is a considerable hidden danger in terms of fire prevention and theft prevention in both the community and the factory; there are also some doors in the prior art that are timed to control the rotation through electronic structures, but the use of electronics requires the circuit to be connected, which causes a significant increase in the cost of the building door, and on the other hand, the electronic device is very unstable and easily damaged in environments such as the opening and closing of the building door, and cannot better meet the needs.

[0003] Therefore, it is necessary to solve the above technical problems. Summary of the invention

[0004] In view of the above technical problems, the present invention provides an automatic door closer, which can achieve the effect of timing door closing by proposing a new automatic door closing mechanical structure, and effectively solve the problems existing in the background technology. The technical solution adopted by the present invention is as follows:

[0005] An automatic door closer comprises a housing, a transmission gear, a door shaft and a piston, wherein the transmission gear and the piston are mounted inside the housing, a connecting shaft is located in the middle of the transmission gear, one end of the connecting shaft is fixed to the transmission gear, and the other end extends out of the housing and is connected to the door shaft, wherein the door shaft is also connected to the door, and when the door rotates, the door shaft is driven to rotate, thereby further driving the transmission gear to rotate;

[0006] A piston sliding cylinder is provided inside the shell, and the piston is installed in the piston sliding cylinder, and the side walls on the left and right sides are in contact with the inner wall of the piston sliding cylinder. The piston is hollow inside and has an opening at the upper end. A main shaft spring is installed inside the piston, and one end of the main shaft spring is in contact with the piston, and the other end is in contact with the shell. An opening is provided on the side wall of the piston sliding cylinder close to the transmission gear, and the gear tooth part of the transmission gear passes through the opening and contacts the side wall of the piston. A rack is provided at the part of the piston that contacts the transmission gear and meshes with the transmission gear, and the transmission gear drives the piston to move up and down in the piston sliding cylinder;

[0007] The top of the piston is provided with a convex surface and a rectangular hole, and a large rocker arm, a small rocker arm and a timer assembly are also installed in the shell, wherein the small rocker arm is installed on the timer assembly through the small rocker arm rotating shaft, and the large rocker arm includes a large end and a small end, and the large end part is installed on the top of the piston sliding cylinder through the large rocker arm rotating shaft, and its shape is adapted to the convex surface of the top of the piston. The large rocker arm is driven to rotate by the piston, and the small end part contacts with the small rocker arm, driving the small rocker arm to rotate and further transmitting mechanical energy to the timer assembly.

[0008] The timer assembly includes a turntable, a large reduction wheel, a turntable shaft, a small spring and a ratchet active card, the large reduction wheel includes an inner and outer ring, the outer ring is set as an outer tooth, and the inner ring is set as an inner ratchet, the turntable is set in a space formed by the inner ring of the large reduction wheel, the turntable and the large reduction wheel are both installed on the turntable shaft, wherein the turntable is connected to the turntable shaft through a flat key, the large reduction wheel is movably connected to the turntable shaft, one end of the turntable shaft is fixedly connected to the small rocker arm, and the turntable shaft is driven to rotate by the small rocker arm, the small spring and the ratchet active card are each provided with two, divided into two groups and fixed on both sides of the turntable, one end of the ratchet active card is fixed to the turntable through the rotating shaft, and the other end is contacted and connected with the inner ratchet of the inner ring of the large reduction wheel, one end of the small spring is fixed to the turntable, and the other end is connected to the ratchet active card, so as to facilitate the resetting of the ratchet active card;

[0009] The timer assembly also includes a five-stage reduction gear and a balance wheel, wherein the five-stage reduction gears are installed in sequence from large to small, the smallest stage reduction gear is a ratchet, and the balance wheel includes a pendulum plate and pendulum teeth, the pendulum plate can swing left and right through the pendulum plate shaft, the pendulum teeth include two and are fixed on the pendulum plate, and the two pendulum teeth are alternately contacted and connected with the ratchet wheel back and forth.

[0010] The shell is filled with hydraulic oil, and the first speed regulating throttle and the second speed regulating throttle are successively opened at the bottom of the side wall of the piston sliding cylinder close to the transmission gear, wherein the first speed regulating throttle is connected to the rack part on the piston through the oil channel, and the second speed regulating throttle is connected to the transmission gear through the oil channel, and the hydraulic oil passing through the piston and the transmission gear can return to the top space of the piston, and a first door speed adjusting screw is arranged on the oil channel after the first speed regulating throttle, and a second door speed adjusting screw is arranged on the oil channel after the second speed regulating throttle.

[0011] The small rocker arm is in a "U" shape, and the side of the small rocker arm close to the piston is longer than the other side of the small rocker arm.

[0012] A flow-stop one-way valve is arranged at the bottom of the piston.

[0013] The reduction ratio achieved by the five-stage reduction gear is at least 1000:1.

[0014] The two ratchet active cards rotate in the same direction and remain consistent along the rotating direction of the turntable.

[0015] A spring is also arranged on the back of the rotating disk.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention adopts a purely mechanical structure to complete the operation of automatic door closing, which can realize automatic door closing when the door is opened to more than 90 degrees. It can automatically close the building door in 5 to 10 minutes without any power supply, which is truly convenient, safe and more humane multifunctional door closer.

[0018] 2. The present invention creatively utilizes the characteristics of the balance wheel and the principle that the duration of each swing is the same to achieve the function of automatic timing. In addition, the present invention can adjust the door speed of automatic door closing by designing different deceleration mechanisms.

[0019] 3. In the present invention, the housing is filled with hydraulic oil, and the oil passages are reasonably arranged. By setting the first speed regulating throttle and the second speed regulating throttle, the door speed can be accurately adjusted, further broadening the application scenarios of the present invention.

[0020] In summary, the present invention has an ingenious design and a reasonable structure, can effectively solve the problem in the prior art that building doors cannot be automatically closed, and is suitable for wide promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 It is a front view of the timer assembly structure of the present invention;

[0023] Figure 3 It is a side view of the matching structure of the large reduction wheel and the rotating disk of the present invention;

[0024] Figure 4 It is a top view of the matching structure of the balance wheel and the ratchet wheel of the present invention;

[0025] Figure 5 This is a structural diagram of the piston of the present invention;

[0026] Figure 6 It is a schematic diagram of the principle of the present invention;

[0027] In the figure: 1 is a housing, 2 is a transmission gear, 3 is a door shaft, 4 is a piston, 5 is a piston sliding cylinder, 6 is a main shaft spring, 7 is a large rocker arm, 8 is a small rocker arm, 9 is a timer assembly, 10 is a first speed regulating throttle, 11 is a second speed regulating throttle, 12 is a first door speed adjusting screw, 13 is a second door speed adjusting screw, 14 is a flow-stopping one-way valve, 15 is a spring, 91 is a turntable, 92 is a large reduction wheel, 93 is a turntable shaft, 94 is a small spring, 95 is a ratchet active card, 96 is a ratchet, 97 is a swing plate, and 98 is a swing tooth. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] See also Figures 1 to 6 The present invention provides an automatic door closer, comprising a housing 1, a transmission gear 2, a door shaft 3 and a piston 4. The transmission gear 2 and the piston 4 are installed inside the housing 1. The middle position of the transmission gear 2 is a connecting shaft. One end of the connecting shaft is fixed on the transmission gear 2, and the other end extends out of the housing 1 and is connected to the door shaft 3. The door shaft 3 is also connected to the door. When the door rotates, the door shaft 3 is driven to rotate, and the transmission gear 2 is further driven to rotate.

[0030] A piston sliding cylinder 5 is provided inside the housing 1. The piston 4 is installed in the piston sliding cylinder 5. The side walls on the left and right sides are fitted with the inner wall of the piston sliding cylinder 5. The piston 4 can slide up and down inside the piston sliding cylinder 5. The piston 4 is hollow inside and has an upper end. A main shaft spring 6 is installed inside the piston 4. One end of the main shaft spring 6 contacts the piston 4, and the other end contacts the housing 1. An opening is provided on the side wall of the piston sliding cylinder 5 close to the transmission gear 2. The gear tooth part of the transmission gear 2 contacts the side wall of the piston 4 through the opening. The part of the piston 4 that contacts the transmission gear 2 is provided with a rack and meshes with the transmission gear 2. The transmission gear 2 drives the piston 4 to move up and down in the piston sliding cylinder 5.

[0031] The top of the piston 4 is provided with a convex surface and a rectangular hole, and a large rocker arm 7, a small rocker arm 8 and a timer assembly 9 are also installed in the housing 1, wherein the small rocker arm 8 is installed on the timer assembly 9 through the small rocker arm shaft, the large rocker arm 7 includes a large end and a small end, and the large end part is installed on the top of the piston sliding cylinder 5 through the large rocker arm shaft, and its shape is adapted to the convex surface on the top of the piston 4. The large rocker arm 7 is driven by the piston 4 to rotate, and the small end part contacts the small rocker arm 8, driving the small rocker arm 8 to rotate and further transmit mechanical energy to the timer assembly 9.

[0032] The timer assembly 9 includes a turntable 91, a large reduction wheel 92, a turntable shaft 93, a small spring 94 and a ratchet movable card 95. The large reduction wheel 92 includes an inner and outer ring. The outer ring is set as an outer tooth, and the inner ring is set as an inner ratchet. The turntable 91 is set in the space formed by the inner ring of the large reduction wheel 92. The turntable 91 and the large reduction wheel 92 are both installed on the turntable shaft 93, wherein the turntable 91 is connected to the turntable shaft 93 through a flat key, and the large reduction wheel 92 is movably connected to the turntable shaft 93. One end of the disc shaft 93 is fixedly connected to the small rocker arm 8, and the turntable shaft 93 is driven to rotate by the small rocker arm 8. The small spring 94 and the ratchet active card 95 are each provided with two, which are divided into two groups and fixed on both sides of the turntable 91. One end of the ratchet active card 95 is fixed to the turntable 91 through the rotating shaft, and the other end is in contact with the inner ratchet of the inner ring of the large reduction wheel 92. One end of the small spring 94 is fixed to the turntable 94, and the other end is connected to the ratchet active card 95, so as to facilitate the resetting of the ratchet active card 95.

[0033] The timer assembly 9 also includes a five-stage reduction gear and a balance wheel, wherein the five-stage reduction gears are installed in sequence from large to small, and the smallest stage reduction gear is a ratchet 96. The balance wheel includes a pendulum plate 97 and a pendulum tooth 98. The pendulum plate 97 can swing left and right through the pendulum plate shaft. The pendulum tooth 98 includes two and is fixed on the pendulum plate 97. The two pendulum teeth 98 are alternately contacted and connected with the ratchet 96 back and forth.

[0034] The shell is filled with hydraulic oil, and the bottom of the side wall of the piston sliding cylinder 5 near the transmission gear 2 is provided with a first speed regulating throttle 10 and a second speed regulating throttle 11 in sequence, wherein the first speed regulating throttle 10 is connected to the rack part on the piston 4 through an oil channel, and the second speed regulating throttle 11 is connected to the transmission gear 2 through an oil channel, and the hydraulic oil passing through the piston 4 and the transmission gear 2 can return to the top space of the piston 4, and a first door speed adjusting screw 12 is provided on the oil channel after the first speed regulating throttle 10, and a second door speed adjusting screw 13 is provided on the oil channel after the second speed regulating throttle 11.

[0035] The small rocker arm 8 is in a "U" shape, and the side of the small rocker arm 8 close to the piston is longer than the other side of the small rocker arm 8. The purpose of the above structural setting is to prevent the small rocker arm 8 from not being able to hold the small end of the large rocker arm 7 well when it hits, causing disengagement.

[0036] A stop check valve 14 is provided at the bottom of the piston 4, and a stop check valve steel ball is provided inside the stop check valve 14. When the door is pushed, the piston 4 moves upward, and the hydraulic oil rushes to the steel ball to move downward, and flows into the cylinder through the steel ball. When the door is closed, the piston 4 moves downward under the pressure of the spindle spring 6, and the hydraulic oil under the piston 4 rushes to the steel ball to move upward, tightly blocking the oil channel. The oil can only pass through the first speed regulating throttle 10 or the second speed regulating throttle 11, and the cycle is repeated. The size of the oil channel opening can be controlled by the first door speed adjusting screw 12 and the second door speed adjusting screw 13.

[0037] The reduction ratio achieved by the five-stage reduction gear is at least 1000:1. The opening degree of a normal building door or fire door can reach 120 degrees. According to the swing time of the swing plate 97, when the reduction ratio is 1000:1, when the door is pushed to 90 to 100 degrees, the closing time is about 5 minutes. If it is pushed hard to 110 to 120 degrees, the time is about 10 minutes. If it is considered that the time is not enough, the door can be pushed again when it starts to close, which is equivalent to another cycle. The timing starts again and the cycle continues.

[0038] The two ratchet active cards 95 have the same rotation direction and are kept consistent along the rotation direction of the turntable 91. The use of two ratchet active cards 95 can keep the force on both sides of the large reduction wheel 92 uniform. As a preferred embodiment, the back of the turntable 91 described in this embodiment is also provided with a spring 15, which serves as an auxiliary force for the restoring force of the main shaft spring 6 to push the large reduction wheel 92 to rotate. On the other hand, the function of the spring 15 is to keep the ratchet active card 95 always in contact with the large reduction wheel 92 to avoid disengagement.

[0039] The inventive principle and operation process of the present invention are as follows:

[0040] During the process of opening the door to 0-90°: the building door drives the door shaft 3 to rotate clockwise, and the door shaft 3 further drives the transmission gear 2 to rotate clockwise. At this time, the piston 4 moves upward, the main shaft spring 6 is compressed, and the hydraulic oil inside the piston 4 moves downward. At this time, the stop-flow one-way valve 14 is in an open state, and the hydraulic oil inside the piston 4 enters the piston sliding cylinder 5 under the piston 4, and enters the upper and lower oil channels to complete the circulation, and continues to open until the building door is opened to 90°. At this time, the convex surface on the top of the piston 4 contacts the large end of the large rocker arm 7, causing the large end of the large rocker arm 7 to start to rotate clockwise, driving the small end to rotate clockwise to the small rocker arm 8, but does not cause the small rocker arm 8 to rotate. At this time, the timer assembly 9 does not work.

[0041] When the door is released, the piston 4 begins to slowly descend under the action of the main shaft spring 6, driving the transmission gear 2 to start rotating counterclockwise, and the door is slowly closed. The hydraulic oil under the piston goes up and holds the stop check valve steel ball inside the stop check valve 14. The hydraulic oil under the piston 4 can only flow back through the first speed regulating throttle 10 and the second speed regulating throttle 11. The closing speed of the door can be controlled by adjusting the first door speed adjusting screw 12 and the second door speed adjusting screw 13. When the piston 4 descends to block the first speed regulating throttle 10, the first speed regulating throttle 10 begins to not work. At this time, the opening angle of the door is about 20°, that is, the closing speed is adjusted by the second door speed adjusting screw 13. The purpose of the above-mentioned structural setting is to control the door to slow down in the final stage of closing, so that the closing process is divided into two speeds to meet the needs of different scenarios.

[0042] When the door is opened more than 90°, the small end of the large rocker arm 7 increases its clockwise rotation degree, driving the small rocker arm 8 to start counterclockwise rotation, and the timer assembly starts to work. Since the small rocker arm 8 is fixed on the turntable shaft 93, the turntable 91 is also fixed on the turntable shaft 93, and the large reduction wheel 92 is movably mounted on the turntable shaft 93, the small rocker arm 8 only drives the turntable 91 to rotate counterclockwise, and further drives the ratchet active card 95 on the turntable 91 to rotate counterclockwise. The inner ring of the large reduction wheel 92 is set as an inner ratchet. Since the direction of the inner ratchet is the same as the rotation direction of the ratchet active card 95, the ratchet active card 95 can rotate on the inner ratchet of the large reduction wheel 92 with almost no resistance, while the large reduction wheel 92 hardly rotates.

[0043] When the door is released, the piston 4 begins to slowly move downward under the action of the main shaft spring 6. Since the top of the piston 4 is provided with a rectangular hole, the large end of the large rocker arm 7 can be driven to rotate counterclockwise, and the small end of the large rocker arm 7 also begins to rotate counterclockwise, further driving the small rocker arm 8 to rotate clockwise. At this time, since the rotation direction of the ratchet active card 95 is opposite to the direction of the inner ratchet of the large reduction wheel 92, the ratchet active card 95 will drive the large reduction wheel 92 to start rotating clockwise. The large reduction wheel 92 is connected with a reduction mechanism. Since the gears of the reduction mechanism are in a state of decreasing wheel diameter, the last stage ratchet 96 of the reduction mechanism should be in the large reduction wheel 92. The ratchet wheel 96 is accelerated under the action of the reduction wheel 92, but a balance wheel is arranged above the ratchet wheel 96, and the balance wheel includes a swing plate 97 and a swing tooth 98. The ratchet wheel 96 is connected with the swing tooth 98. The swing plate 97 is driven by the swing tooth 98 to start swinging to the left along the swing plate axis. The swing tooth 98 on the left side that acts as a block is separated from the ratchet wheel 96, and the swing tooth 98 on the right side acts as a push, so that the ratchet wheel 96 can start to rotate. When the ratchet wheel 96 just rotates a little, the swing plate 96 will reset under the action of universal gravitation and swing back to the original position, that is, the swing tooth 98 on the left side that acts as a block is in contact with the ratchet wheel 96 again, preventing the ratchet wheel 96 from continuing to rotate.

[0044] In this way, the ratchet 96 will rotate little by little under the reciprocating swinging action of the swing plate 97, and the effect of feedback to the large reduction wheel 92 is that the large reduction wheel 92 cannot rotate quickly. Furthermore, the turntable 92 cannot rotate quickly and the small rocker arm 8 cannot rotate quickly either, until the ratchet 96 completes the whole journey little by little. At this time, the small rocker arm 8 returns to its original position driven by the large reduction wheel 92, and the large rocker arm 7 breaks away from the embrace of the small rocker arm 8. At this time, the opening and closing position of the door returns to the 90° position, returning to the aforementioned process.

[0045] The process involved in the present invention also controls the circulation speed of the hydraulic oil through the first door speed adjusting screw 12 and the second door speed adjusting screw 13. The oil channel behind the first door speed throttle 10 is also connected to the rack part of the side wall of the piston 4, and the oil channel behind the second door speed throttle 11 is connected to the transmission gear 2, which plays the role of lubricating oil to a certain extent. The hydraulic oil inside the entire shell is interconnected, and the flow speed of the hydraulic oil is only controlled by the first door speed adjusting screw 12 and the second door speed adjusting screw 13, thereby further controlling the closing speed of the door.

[0046] Only the preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention, and various changes should be included in the protection scope of the present invention.

Claims

1. An automatic door closer, characterized in that: It comprises a housing (1), a transmission gear (2), a door shaft (3) and a piston (4), wherein the transmission gear (2) and the piston (4) are installed inside the housing (1), the middle position of the transmission gear (2) is a connecting shaft, one end of the connecting shaft is fixed on the transmission gear (2), and the other end extends out of the housing (1) and is connected to the door shaft (3), and the door shaft (3) is also connected to the door, and when the door rotates, the door shaft (3) is driven to rotate, and further drives the transmission gear (2) to rotate; A piston sliding cylinder (5) is arranged inside the housing (1), the piston (4) is installed in the piston sliding cylinder (5), the side walls on the left and right sides are in contact with the inner wall of the piston sliding cylinder (5), the piston (4) is hollow inside and has an opening at the upper end, a main shaft spring (6) is arranged inside the piston (4), one end of the main shaft spring (6) is in contact with the piston (4), and the other end is in contact with the housing (1), an opening is arranged on the side wall of the piston sliding cylinder (5) close to the transmission gear (2), the gear teeth of the transmission gear (2) pass through the opening and contact with the side wall of the piston (4), a rack is arranged on the part of the piston (4) in contact with the transmission gear (2) and meshes with the transmission gear (2), and the transmission gear (2) drives the piston (4) to move up and down in the piston sliding cylinder (5); The top of the piston (4) is provided with a convex surface and a rectangular hole. A large rocker arm (7), a small rocker arm (8) and a timer assembly (9) are also installed in the housing (1), wherein the small rocker arm (8) is installed on the timer assembly (9) through a small rocker arm rotating shaft. The large rocker arm (7) includes a large end and a small end. The large end portion is installed on the top of the piston sliding cylinder (5) through the large rocker arm rotating shaft. The shape of the large rocker arm (7) is adapted to the convex surface on the top of the piston (4). The large rocker arm (7) is driven by the piston (4) to rotate, and the small end portion contacts the small rocker arm (8), thereby driving the small rocker arm (8) to rotate and further transmitting mechanical energy to the timer assembly (9); The timer assembly (9) comprises a rotating disk (91), a large reduction wheel (92), a rotating disk shaft (93), a small spring (94) and a ratchet movable clamp (95); the large reduction wheel (92) comprises an inner and outer ring, the outer ring is provided with outer teeth, and the inner ring is provided with inner ratchet teeth; the rotating disk (91) is arranged in a space formed by the inner ring of the large reduction wheel (92); the rotating disk (91) and the large reduction wheel (92) are both mounted on the rotating disk shaft (93); the rotating disk (91) is connected to the rotating disk shaft (93) by a flat key, and the large reduction wheel (92) is movably connected to the rotating disk shaft (93) One end of the turntable shaft (93) is fixedly connected to the small rocker arm (8), and the turntable shaft (93) is driven to rotate by the small rocker arm (8). Two small springs (94) and two ratchet active clamps (95) are respectively provided, and are divided into two groups and fixed on both sides of the turntable (91). One end of the ratchet active clamp (95) is fixed to the turntable (91) through a rotating shaft, and the other end is contacted and connected with the inner ratchet teeth of the inner ring of the large reduction wheel (92). One end of the small spring (94) is fixed to the turntable (91), and the other end is connected to the ratchet active clamp (95), so as to facilitate the resetting of the ratchet active clamp (95); The timer assembly (9) further comprises a five-stage reduction gear and a balance wheel, wherein the five-stage reduction gears are installed in sequence from large to small, the smallest stage reduction gear is a ratchet (96), the balance wheel comprises a wobble plate (97) and a swing tooth (98), the wobble plate (97) can swing left and right through a wobble plate shaft, the swing tooth (98) comprises two and is fixed on the wobble plate (97), and the two swing teeth (98) are alternately contacted and connected with the ratchet (96) back and forth; The housing is filled with hydraulic oil, and a first speed regulating throttle (10) and a second speed regulating throttle (11) are sequentially provided at the bottom of the side wall of the piston sliding cylinder (5) close to the transmission gear (2), wherein the first speed regulating throttle (10) is connected to the rack part on the piston (4) through an oil passage, and the second speed regulating throttle (11) is connected to the transmission gear (2) through an oil passage, and the hydraulic oil passing through the piston (4) and the transmission gear (2) can return to the top space of the piston (4), and a first door speed adjusting screw (12) is provided on the oil passage after the first speed regulating throttle (10), and a second door speed adjusting screw (13) is provided on the oil passage after the second speed regulating throttle (11).

2. An automatic door closer according to claim 1, characterized in that: The small rocker arm (8) is in a "U" shape, and the side of the small rocker arm (8) close to the piston is longer than the other side of the small rocker arm (8).

3. The automatic door closer according to claim 1, characterized in that: A flow-stop one-way valve (14) is provided at the bottom of the piston (4).

4. The automatic door closer according to claim 1, characterized in that: The reduction ratio achieved by the five-stage reduction gear is at least 1000:

1.

5. The automatic door closer according to claim 1, characterized in that: The two ratchet movable clamps (95) rotate in the same direction and keep the same direction along the rotation of the rotating disk (91).

6. The automatic door closer according to claim 1, characterized in that: A spring (15) is also provided on the back of the rotating disk (91).

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