Door closer

Abstract

The utility model relates to the technical field of door closers, in particular to a door closer which is provided with a pull rod, a bearing seat, a control assembly, a sliding block assembly and a locking assembly. Opening and closing of the door leaf drive the pull rod to move; the bearing seat sleeves the outer side of the pull rod; the locking assembly comprises a locking piece which is arranged in the bearing base and arranged on the outer side of the pull rod in a sleeving mode. The control assembly is used for controlling movement of the sliding block assembly. The sliding block assembly can abut against the locking piece, so that the locking piece is in friction fit with the pull rod, meanwhile, the pull rod is locked through the locking piece, the pull rod can be limited and located at any position, and therefore it is guaranteed that the door leaf can be located at will, and personnel circulation or goods transportation is facilitated. In addition, the locking piece is adopted, the overall structure is reasonable and compact, operation is convenient and easy, safety, practicability and reliability are achieved, and application and popularization in different occasions are facilitated.

Description

Technical Field

[0001] This utility model relates to the field of door closers, and in particular to a door closer. Background Technology

[0002] In the construction industry, door closers are widely used to automatically close doors, improving convenience and ensuring building safety and sealing. However, existing products have significant drawbacks. First, doors often need to stop at specific positions during use, such as when moving large items; however, most door closers only have opening and closing functions and lack a mid-way positioning mechanism, failing to meet these needs. Second, to achieve automatic closing, door closers have complex internal structures, including numerous gears, linkages, complex hydraulic circuits, and precision valves, resulting in high manufacturing and maintenance costs and reducing operational stability and reliability. Utility Model Content

[0003] Therefore, the purpose of this utility model is to provide a door closer.

[0004] The present invention adopts the following technical solution:

[0005] A door closer includes a pull rod having a connecting end for connecting to a door leaf. The door closer also includes a support base, a control assembly, a slider assembly installed within the support base, and a locking assembly. The pull rod passes sequentially through the slider assembly, the locking assembly, and the support base. The locking assembly includes a locking plate disposed within the support base and sleeved on the outside of the pull rod. The control assembly includes a locking switch pivotally connected to the support base and a control handle. The locking switch includes a limiting arm, and the control handle is used to swing up and down relative to the support base to move the limiting arm up and down. The slider assembly includes a slider base through which the pull rod passes, a slider spring installed on the slider base, and a pressing block. The slider base has a groove with its opening facing the locking plate. The pressing block is slidably disposed within the groove, and the two ends of the slider spring are respectively connected to the groove and the pressing block. The pressing block has protrusions on both sides.

[0006] The door closer has a first state and a second state from which it transitions;

[0007] When the door closer is in the first state, the limiting arm abuts against the protrusion to restrict the movement of the squeezing block along the axial direction of the pull rod by the push of the slider spring. At this time, the squeezing block separates from the locking plate, so that the pull rod can move relative to the locking plate.

[0008] When the door closer is in the second state, the limiting arm separates from the protrusion, and the slider spring applies a spring force to the pressing block in the axial direction of the pull rod, causing the pressing block to press the locking plate to tilt relative to the pull rod, so that the locking plate moves synchronously with the pull rod.

[0009] Preferably, the locking piece is annular and includes an inner circular friction surface; the locking assembly further includes an unlocking elastic element sleeved on the outside of the pull rod, one end of which is connected to the locking piece; when the pressing block separates from the locking piece, the unlocking elastic element drives the locking piece to reset.

[0010] Preferably, the slider assembly further includes a slider faceplate, which is assembled with the slider base to form the groove.

[0011] Preferably, the slider base has a first clearance ramp on the side facing the locking piece, and the inner side of the bearing seat has a second clearance ramp opposite to the first clearance ramp; the first clearance ramp and the second clearance ramp are used to clear the locking piece.

[0012] Preferably, the locking switch includes a return top block and a limiting block disposed on the upper end of the return top block, and the limiting arms are disposed on both sides of the limiting block; the return top block is used to cooperate with the pressing block to drive the control handle and the locking switch to move upward.

[0013] Preferably, the return block includes a reset component and a plurality of abutment pieces installed inside the reset component; push arms extend from both sides of the reset component.

[0014] Preferably, the outer wall of the slider base is provided with a first connecting groove and a second connecting groove that communicate with the slide groove. The first connecting groove is used to cooperate with the push arm, and the second connecting groove is used to cooperate with the limiting arm.

[0015] Preferably, it further includes a positioning component, which includes a pin and a clamping spring. The two ends of the clamping spring are respectively connected to the support seat and the pin. One side of the return block is provided with a first abutting surface and a second abutting surface that are inclined to each other. The clamping spring drives the pin to abut against the first abutting surface or the second abutting surface to achieve positioning of the control handle.

[0016] Preferably, it further includes an elastic mechanism, which includes a cylindrical shell, a piston assembly, and a main spring. The piston assembly is located inside the cylindrical shell and is fastened to one end of the pull rod. The main spring is sleeved on the outside of the pull rod, and its two ends respectively abut against the piston assembly and the cylindrical shell.

[0017] A door closer includes a pull rod having a connecting end for connecting to a door leaf. The door closer further includes a support base, a control assembly, a slider assembly installed within the support base, and a locking assembly. The pull rod passes sequentially through the slider assembly, the locking assembly, and the support base. The locking assembly includes a locking piece disposed within the support base and sleeved on the outside of the pull rod. The control assembly includes a locking switch pivotally connected to the support base and a control handle. The locking switch includes a return block and a limiting arm. The control handle is used to swing up and down relative to the support base to move the limiting arm up and down. The slider assembly includes a slider base through which the pull rod passes, a slider spring installed on the slider base, and a pressing block. The slider base has a groove with its opening facing the locking piece. The pressing block is slidably disposed within the groove. The two ends of the slider spring are respectively connected to the groove and the pressing block. Protrusions are provided on both sides of the pressing block.

[0018] The door closer has a first state, a second state transitioning from the first state, a third state transitioning from the second state, and a fourth state transitioning from the third state;

[0019] When the door closer is in the first state, the limiting arm abuts against the protrusion to restrict the movement of the squeezing block along the axial direction of the pull rod by the push of the slider spring. At this time, the squeezing block separates from the locking plate, so that the pull rod can move relative to the locking plate.

[0020] When the door closer is in the second state, the control handle moves downward, the limiting arm separates from the protrusion, and the slider spring applies a spring force to the pressing block along the axial direction of the pull rod, causing the pressing block to press the locking piece to tilt relative to the pull rod, so that the locking piece and the pull rod move synchronously.

[0021] When the door closer is in the third state, the pull rod retracts, causing the locking plate and the pressing block to move along the axial direction of the pull rod; the pressing block compresses the slider spring and moves along the axial direction of the pull rod; the pressing block abuts against the slider base, locking the pull rod; at the same time, the pressing block cooperates with the return top block to lift the control handle.

[0022] When the door closer is in the fourth state, the locking plate and the pull rod move along the axial direction of the pull rod, the limiting arm abuts against the protrusion, so that the pressing block separates from the locking plate, and the pull rod can move relative to the locking plate.

[0023] The beneficial effects of this utility model are as follows:

[0024] The door closer of this utility model includes a pull rod, a support base, a control component, a slider assembly, and a locking component. The pull rod is used to connect to the door leaf, and the opening and closing of the door leaf drives the movement of the pull rod. The support base is sleeved on the outside of the pull rod. The locking component includes a locking piece disposed inside the support base and sleeved on the outside of the pull rod. The control component is used to control the movement of the slider assembly. The slider assembly can abut against the locking piece, so that the locking piece and the pull rod are in frictional engagement. At the same time, the locking piece is used to lock the pull rod, which can restrict the pull rod to any position, thereby ensuring that the door leaf can be positioned arbitrarily, facilitating the flow of people or the transportation of goods. In addition, the use of a locking piece results in a reasonable and compact overall structure, convenient and easy operation, safety, practicality, and reliability, making it suitable for widespread use in various occasions. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the door closer of this utility model;

[0026] Figure 2 for Figure 1 An exploded view of the structure of a door closer;

[0027] Figure 3 for Figure 2 A schematic diagram of the structure after concealing the pull rod and elastic mechanism;

[0028] Figure 4 for Figure 2 A half-sectional view of the bearing seat in the middle;

[0029] Figure 5 for Figure 2 A schematic diagram of the locking switch in the middle;

[0030] Figure 6 for Figure 2 A schematic diagram of the slider assembly in the diagram;

[0031] Figure 7 This is a schematic diagram of the door closer of this utility model in its first state;

[0032] Figure 8 This is a schematic diagram of the door closer of this utility model in its second state;

[0033] Figure 9 This is a schematic diagram of the door closer of this utility model in the third state;

[0034] Figure 10 This is a schematic diagram of the door closer of this utility model in its fourth state.

[0035] Numbering on the map:

[0036] 10-Pull rod; 20-Bearing seat; 21-Second clearance ramp; 22-Mounting cavity; 23-Mounting seat; 231-Pivot hole; 232-Through groove; 24-Slot; 30-Control assembly; 31-Control handle; 32-Locking switch; 33-Returning top block; 34-Reset component; 341-Push arm; 35-Abutting piece; 351-First abutting surface; 352-Second abutting surface; 36-Limiting block; 37-Limiting arm; 40-Slider assembly; 41-Slider Base; 411-First clearance slope; 412-Slide groove; 413-First connecting groove; 414-Second connecting groove; 42-Slider spring; 43-Extrusion block; 431-Protrusion; 44-Slider face cover; 50-Locking assembly; 51-Locking piece; 511-Inner circular friction surface; 52-Unlocking elastic element; 60-Positioning assembly; 61-Ejector pin; 62-Clamping spring; 70-Elastic mechanism; 71-Cylindrical outer shell; 72-Piston assembly; 73-Main spring. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0038] In the description of this utility model, it should be noted that the terms "vertical direction," "up," "down," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or a connection 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 utility model according to the specific circumstances.

[0040] like Figures 1 to 10As shown, this is the door closer of the present invention, which is applied to a door leaf and can restrict the door leaf to any opening and closing angle to meet the usage requirements.

[0041] The aforementioned door closer includes a pull rod 10 with a connecting end for connecting to a door leaf. The door closer also includes a support base 20, a control component 30, a slider assembly 40, a locking component 50, and a positioning component 60. The support base 20 is sleeved on the outside of the pull rod 10, and the control component 30, slider assembly 40, locking component 50, and positioning component 60 are all mounted on the support base 20. The locking component 50 includes a locking piece 51 located inside the support base 20 and sleeved on the outside of the pull rod 10. The pull rod 10 is locked or unlocked through the interlocking of the control component 30, slider assembly 40, and locking component 50, thus restricting the door leaf to a certain angle.

[0042] Please see Figures 1 to 4 The support base 20 is cylindrical in shape. An inner cavity 22 for assembling the slider assembly 40 is provided inside the support base 20. An outer wall of the support base 20 has a mounting seat 23 for pivotally connecting the control assembly 30, and the mounting seat 23 has a pivot hole 231. A through groove 232 connecting the mounting seat 23 to the mounting cavity 22 is provided in the middle of the mounting seat 23. The outer wall of the support base 20 also has a slot 24 for mounting the positioning assembly 60. During assembly, the control assembly 30 is rotatably connected to the mounting seat 23 via a pin. When the control assembly 30 flips up and down, it can extend into the mounting cavity 22 through the through groove 232. A second clearance slope 21 is provided inside the support base 20 to prevent the locking plate 51 from tilting, thus keeping the locking plate 51 in an inclined state.

[0043] Please see Figure 1 , Figure 2 , Figure 3 , Figure 5 The control assembly 30 includes a control handle 31 and a locking switch 32. The control handle 31 is mounted on the outside of the support base 20, and the locking switch 32 is fixed to the inside of the control handle 31 and rotatably connected to the support base 20 via a pin. The locking switch 32 includes a return top block 33 and a limiting block 36 located on the upper end of the return top block 33. Further, the return top block 33 includes a reset member 34 and a plurality of abutment pieces 35 mounted on the inside of the reset member 34. The reset member 34 has an inverted U-shaped structure and push arms 341 extending on both sides. In addition, one side of the push arm 341 has an inclined surface. The plurality of abutment pieces 35 are stacked between two push arms 341 and fixedly connected to the reset member 34 via two pins. After the plurality of abutment pieces 35 are stacked, a first abutment surface 351 and a second abutment surface 352 that are inclined to each other are formed on one side. Further, the limiting block 36 has an inverted U-shaped structure, and limiting arms 37 are provided on both sides of the limiting block 36.

[0044] Please see Figure 1 , Figure 2 , Figure 3 , Figure 6 and Figure 7 The slider assembly 40 includes a slider base 41, a slider spring 42, a pressing block 43, and a slider faceplate 44. The slider base 41 is slidably connected to the inner side of the support seat 20. On the side of the slider base 41 facing the locking piece 51, there is a first clearance slope 411 opposite to the second clearance slope 21. The first clearance slope 411 is used to prevent the locking piece 51 from being obstructed, so that the locking piece 51 can remain in an inclined state. The outer side of the slider base 41 has a slot. The slider faceplate 44 is fitted into the slot and forms a sliding groove 412 opening towards the locking piece 51. A first connecting groove 413 and a second connecting groove 414 communicating with the sliding groove 412 are also formed on the outer wall of the slider base 41. The pressing block 43 is slidably connected within the sliding groove 412. The two ends of the slider spring 42 are respectively connected to the sliding groove 412 and the pressing block 43. Meanwhile, protrusions 431 are provided on both sides of the pressing block 43.

[0045] Please see Figure 1 , Figure 2 , Figure 3 and Figure 7 The locking assembly 50 includes a locking plate 51 and an unlocking elastic element 52. The locking plate 51 is annular and includes an inner circular friction surface 511. It should be noted that the inner circular friction surface 511 of the locking plate 51 is always in contact with the outer wall of the pull rod 10. When the locking plate 51 is placed vertically, the friction between the inner circular friction surface 511 and the outer wall of the pull rod 10 is relatively small, allowing the pull rod 10 to move back and forth relative to the locking plate 51. When the locking plate 51 is tilted, the friction between the inner circular friction surface 511 and the outer wall of the pull rod 10 increases, enabling the locking plate 51 and the pull rod 10 to move synchronously. The unlocking elastic element 52 is sleeved on the outside of the pull rod 10. One end of the unlocking elastic element 52 is connected to the locking piece 51, and the other end of the unlocking elastic element 52 is connected to the slider base 41. The unlocking elastic element 52 is used to drive the locking piece 51 to reset, so that the locking piece 51 is reset from the inclined state to the vertical state, thereby reducing the friction between the inner circle friction surface 511 and the outer wall of the pull rod 10, so that the pull rod 10 can move relative to the locking piece 51.

[0046] Please see Figure 2 and Figure 3 The positioning component 60 includes a pin 61 and a clamping spring 62. The two ends of the clamping spring 62 are connected to the support seat 20 and the pin 61, respectively. The clamping spring 62 drives the pin 61 to abut against the first abutting surface 351 or the second abutting surface 352 to achieve positioning of the control handle 31.

[0047] Please see Figure 1 and Figure 2It also includes a spring mechanism 70, which comprises a cylindrical outer shell 71, a piston assembly 72, and a main spring 73. The piston assembly 72 is located inside the cylindrical outer shell 71 and is fastened to one end of the pull rod 10. The main spring 73 is sleeved on the outside of the pull rod 10, with its two ends respectively in contact with the piston assembly 72 and the cylindrical outer shell 71. When the door is opened, the pull rod 10 extends against the spring force of the main spring 73; when there is no force, the main spring 73 drives the pull rod 10 to retract.

[0048] The working principle of the door closer involved in this utility model is as follows:

[0049] like Figure 7 As shown, the door closer is in the first state at this time. The limiting arm 37 abuts against the protrusions 431 on both sides of the squeezing block 43. The movement of the squeezing block 43 along the axial direction of the pull rod 10 is restricted. Therefore, the squeezing block 43 is separated from the locking plate 51. At this time, the locking plate 51 is in a vertical state, and the pull rod 10 can retract or extend relative to the locking plate 51.

[0050] like Figure 8 As shown, pushing the door leaf causes the pull rod 10 to compress the main spring 73 and extend it outward in direction A (the direction of the pull rod 10's axial extension). When it is necessary to stop at a certain angle, press the control handle 31. The control handle 31 causes the locking switch 32 to flip towards the support seat 20. Figure 7 The direction C in the middle causes the door closer to enter the second state. During the flipping of the control handle 31, the abutment piece 35 of the locking switch 32 passes over the ejector pin 61, and the ejector pin 61 abuts against the second abutment surface 352, thus restricting and positioning the control handle 31. At the same time, the push arm 341 of the return block 33 extends into the first connecting groove 413 and abuts against the bottom of the pressing block 43; in addition, the limiting arm 37 of the limiting block 36 moves down and disengages from the protrusions 431 on both sides of the pressing block 43. The pressing block 43 extends outward under the action of the slider spring 42 and abuts against the locking piece 51, causing the locking piece 51 to tilt; specifically, the friction between the inner circular friction surface 511 of the locking piece 51 and the outer wall of the pull rod 10 increases, thus fastening the locking piece 51 and the pull rod 10 together.

[0051] like Figure 9As shown, after the door is released, the pull rod 10 and the locking plate 51 retract synchronously in direction B (the direction of the axis of the pull rod 10) under the restoring action of the main spring 73. During the movement of the locking plate 51, it drives the pressing block 43, which is against it, to overcome the elastic force of the unlocking elastic element 52 and move along the slide groove 412 until the bottom of the pressing block 43 abuts against the bottom of the slide groove 412. At this time, the pull rod 10 stops retracting and is restricted and positioned, so that the door is fixed at a certain angle. At the same time, when the pressing block 43 moves along the slide groove 412 in direction B, the bottom of the pressing block 43 pushes the push arm 341 of the return top block 33. Since one side of the push arm 341 is inclined, under the action of the inclined surface, the locking switch 32 rotates upward, so that the control handle 31 moves along the slide groove 412. Figure 8 The direction D in the middle is reset, allowing the door closer to enter as shown. Figure 9 The third state is shown. At the same time, the abutment piece 35 of the locking switch 32 passes over the ejector pin 61, and the ejector pin 61 abuts against the first abutment surface 351, so that the control handle 31 is restricted and positioned.

[0052] like Figure 10 As shown, to release the positioning, simply push the door leaf in direction A (the direction of the extension of the axis of the pull rod 10) and release, causing the door closer to enter the fourth state. During this process, the pull rod 10 drives the locking plate 51 to move in direction A, while the pressing block 43 moves along the slide groove 412 in direction A under the elastic force of the slider spring 42 and abuts against the limiting arm 37 of the limiting block 36. At this time, the pressing block 43 disengages from the locking plate 51; the unlocking elastic element 52 drives the locking plate 51 to return to the vertical state, that is, the friction between the inner circular friction surface 511 and the outer wall of the pull rod 10 is reduced, releasing the tightness between the two; the pull rod 10 can freely retract or extend, that is, the door leaf can be opened and closed at will.

[0053] Compared to existing technologies, the door closer of this utility model includes a pull rod 10, a support seat 20, a control component 30, a slider assembly 40, and a locking component 50. The pull rod 10 is used to connect to the door leaf, and the opening and closing of the door leaf drives the movement of the pull rod 10. The support seat 20 is sleeved on the outside of the pull rod 10. The locking component 50 includes a locking piece 51 disposed inside the support seat 20 and sleeved on the outside of the pull rod 10. The control component 30 is used to control the movement of the slider assembly 40. The slider assembly 40 can abut against the locking piece 51, so that the locking piece 51 and the pull rod 10 are in frictional engagement. At the same time, the locking piece 51 is used to lock the pull rod 10, which can restrict the pull rod 10 to any position, thereby ensuring that the door leaf can be positioned arbitrarily, facilitating the flow of people or the transportation of goods. In addition, the use of the locking piece 51 results in a reasonable and compact overall structure, convenient and easy operation, safety, practicality, and reliability, making it suitable for widespread use in various occasions.

[0054] The above description merely illustrates the preferred technical solution of this utility model, and while the description is relatively specific and detailed, it should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and this utility model also intends to include these modifications and variations.

Claims

1. A door closer comprising a pull rod having a connecting end for connection to a door leaf, characterised in that, The door closer further comprises a bearing seat, a control assembly, a slider assembly and a locking assembly installed in the bearing seat; the pull rod passes through the slider assembly, the locking assembly and the bearing seat in sequence; the locking assembly comprises a locking piece installed in the bearing seat and sleeved on the outer side of the pull rod; the control assembly comprises a locking switch and a control handle pivoted on the bearing seat, the locking switch comprises a limiting arm, and the control handle is used for swinging up and down relative to the bearing seat to drive the limiting arm to move up and down; the slider assembly comprises a slider base for the pull rod to pass through, a slider spring and a pressing block installed on the slider base, the slider base is provided with a sliding groove, and the opening of the sliding groove is arranged towards the locking piece; the pressing block is slidingly arranged in the sliding groove, and the two ends of the slider spring are connected with the sliding groove and the pressing block respectively; the two sides of the pressing block are provided with protruding blocks; The door closer has a first state and a second state transformed from the first state; When the door closer is in the first state, the limiting arm abuts against the protruding blocks to limit the movement of the pressing block in the axial direction of the pull rod under the pushing of the slider spring, at this time, the pressing block is separated from the locking piece, so that the pull rod can move relative to the locking piece; When the door closer is in the second state, the limiting arm is separated from the protruding blocks, the slider spring applies an elastic force in the axial direction of the pull rod to the pressing block, so that the pressing block presses the locking piece to tilt relative to the pull rod, so as to cause the locking piece to move synchronously with the pull rod.

2. A door closer according to claim 1, wherein The locking piece is in a circular ring shape, and the locking piece comprises an inner circular friction surface; the locking assembly further comprises an unlocking elastic piece sleeved on the outer side of the pull rod, one end of the unlocking elastic piece is connected with the locking piece; when the pressing block is separated from the locking piece, the unlocking elastic piece drives the locking piece to reset.

3. A door closer according to claim 1 or claim 2, wherein The slider assembly further comprises a slider surface cover, and the slider surface cover is assembled and connected with the slider base to form the sliding groove.

4. The door closer of claim 1, wherein One side of the slider base towards the locking piece is provided with a first emptying inclined surface, and the inner side of the bearing seat is provided with a second emptying inclined surface arranged opposite to the first emptying inclined surface; the first emptying inclined surface and the second emptying inclined surface are used for emptying the locking piece.

5. The door closer of claim 1, wherein The locking switch comprises a return top block and a limiting block arranged on the upper end of the return top block, and the limiting arm is arranged on both sides of the limiting block; the return top block is used for cooperating with the pressing block to drive the control handle and the locking switch to move upwards.

6. A door closer according to claim 5, wherein The return top block comprises a reset piece and a plurality of abutting pieces installed on the inner side of the reset piece; the two sides of the reset piece are extended to be provided with pushing arms.

7. A door closer according to claim 6, wherein The outer wall of the slider base is provided with a first connecting groove and a second connecting groove in communication with the sliding groove, the first connecting groove is used for cooperating with the pushing arm, and the second connecting groove is used for cooperating with the limiting arm.

8. A door closer according to claim 5, wherein The positioning assembly comprises a thimble and a clamping spring, and two ends of the clamping spring are connected with the bearing seat and the thimble respectively; one side of the return top block is provided with a first abutting surface and a second abutting surface which are mutually inclined; the clamping spring drives the thimble to abut against the first abutting surface or the second abutting surface, so as to realize the positioning of the control handle.

9. The door closer of claim 1, wherein The elastic mechanism comprises a cylindrical shell, a piston assembly and a main spring, the piston assembly is arranged on the inner side of the cylindrical shell and is tightly connected with one end of the pull rod, and the main spring is sleeved on the outer side of the pull rod and is in abutting contact with the piston assembly and the cylindrical shell at two ends respectively.

10. A door closer comprising a pull rod having a connecting end for connection to a door leaf, characterised in that, The door closer further comprises a bearing seat, a control assembly, a sliding block assembly and a locking assembly which are arranged in the bearing seat; the pull rod passes through the sliding block assembly, the locking assembly and the bearing seat in sequence; the locking assembly comprises a locking piece which is arranged in the bearing seat and is sleeved on the outer side of the pull rod; the control assembly comprises a locking switch and a control handle which are pivotally connected to the bearing seat, the locking switch comprises a return top block and a limiting arm, and the control handle is used for swinging up and down relative to the bearing seat to drive the limiting arm to move up and down; the sliding block assembly comprises a sliding block base in which the pull rod is arranged, a sliding block spring and a pressing block which are arranged on the sliding block base, the sliding block base is provided with a sliding groove, and the opening of the sliding groove is arranged towards the locking piece; the pressing block is slidingly arranged in the sliding groove, and two ends of the sliding block spring are connected with the sliding groove and the pressing block respectively; two sides of the pressing block are provided with protrusions. The door closer has a first state, a second state which is transformed from the first state, a third state which is transformed from the second state, and a fourth state which is transformed from the third state; When the door closer is in the first state, the limiting arm abuts against the protrusions to limit the movement of the pressing block along the axial direction of the pull rod under the pushing of the sliding block spring, at this time, the pressing block is separated from the locking piece, so that the pull rod can move relative to the locking piece; When the door closer is in the second state, the control handle moves downwards, the limiting arm is separated from the protrusions, the sliding block spring applies an elastic force along the axial direction of the pull rod to the pressing block, so that the pressing block presses the locking piece to be inclined relative to the pull rod, so as to cause the locking piece to move synchronously with the pull rod; When the door closer is in the third state, the pull rod is retracted to drive the locking piece and the pressing block to move along the axial direction of the pull rod; the pressing block compresses the sliding block spring to move along the axial direction of the pull rod; the pressing block abuts against the sliding block base, so that the pull rod is locked; at the same time, the pressing block cooperates with the return top block to lift the control handle; When the door closer is in the fourth state, the locking piece and the pull rod move along the axial direction of the pull rod, the limiting arm abuts against the protrusions, so that the pressing block is separated from the locking piece, and the pull rod can move relative to the locking piece.

Images