Multi-stage adjustable telescopic structure and tablet chair using same

Abstract

The utility model relates to a multi-stage adjustable telescopic structure and a tablet chair using the same, and belongs to the field of tablet chairs, the multi-stage adjustable telescopic structure and the tablet chair using the multi-stage adjustable telescopic structure are included, the multi-stage adjustable telescopic structure comprises an installation cylinder, an installation cavity is formed in the installation cylinder, and the installation cavity is internally provided with a through hole; a displacement rod is arranged in the mounting cavity in the length direction of the mounting cylinder in a reciprocating sliding mode. A connecting rod is fixedly arranged at one end of the displacement rod and extends out of the mounting cavity; a plurality of positioning holes are formed in the lower side surface of the displacement rod; mounting holes corresponding to the positioning holes are formed in the lower end surface of the outer side wall of the mounting cylinder; the limiting stopper is used for fixing the displacement rod and comprises a positioning pin arranged corresponding to the positioning hole, the positioning pin is vertically arranged, and the positioning pin can be inserted into the mounting hole in a manner of sliding up and down along the mounting hole. According to the fixing structure for fixing the length of the multistage adjustable telescopic structure, relative sliding cannot occur, and the condition of aging failure cannot occur.

Description

Technical Field

[0001] This utility model relates to the field of school chairs, and in particular to a multi-level adjustable telescopic structure and a school chair using the same. Background Technology

[0002] Afternoon naps are essential for teenagers, but due to current limitations, most primary and secondary schools cannot provide suitable nap facilities. To address this, many school chairs with nap functions have emerged. By reclining the backrest, students can semi-recline and rest, thus improving their comfort. For example, patent document CN221730040U discloses a school chair with a convenient reclining backrest, allowing students to semi-recline and rest comfortably. The angle at which the backrest reclines can be freely controlled by adjusting the length of the gas spring, further enhancing comfort. However, the gas spring structure is not always stable and prone to leaks. In such cases, the gas spring length cannot be fixed, causing the backrest to shift. Furthermore, the gas spring's sealing ring is usually made of plastic, which inevitably ages over time, resulting in a shorter lifespan.

[0003] Based on this, the present invention proposes a multi-level adjustable telescopic structure and a school chair using the same, which solves the above-mentioned technical problems by adopting a rigidly connected multi-level adjustable telescopic structure. Utility Model Content

[0004] Based on this, on the one hand, the present invention provides a multi-level adjustable telescopic structure, including a mounting cylinder arranged in a horizontal direction, a mounting cavity formed in the mounting cylinder along its length direction, a displacement rod arranged in the mounting cavity that can reciprocate and slide along the length direction of the mounting cylinder; a connecting rod is fixedly provided at one end of the displacement rod, and the connecting rod extends out of the mounting cavity in a direction away from the displacement rod; a plurality of positioning holes are opened on the lower surface of the displacement rod, the positioning holes are arranged along the length direction of the displacement rod, and a through mounting hole is opened on the lower surface of the outer side wall of the mounting cylinder corresponding to the positioning holes, the mounting holes being arranged in a vertical direction; it also includes a limiter for fixing the displacement rod, the limiter including a positioning pin corresponding to the positioning hole, the positioning pin being vertically arranged, and the positioning pin being slidably inserted into the mounting hole along the mounting hole.

[0005] In this invention, the length of the multi-stage adjustable telescopic structure is its overall length, specifically the length between the end of the connecting rod and the end of the mounting cylinder furthest from the connecting rod. The displacement rod is reciprocally slidable within the mounting cavity along the length of the mounting cylinder. Therefore, by sliding the displacement rod within the mounting cavity, the length of the multi-stage adjustable telescopic structure can be adjusted. During the adjustment process, a limiter can be used to fix the position of the displacement rod within the mounting cylinder, thereby fixing the length of the multi-stage adjustable telescopic structure and completing the length adjustment.

[0006] In this invention, during the length adjustment of the multi-stage adjustable telescopic structure, the limiting device fixes the displacement rod by moving the positioning pin upwards until it is inserted into the positioning hole, thus fixing the position of the displacement rod within the mounting cylinder. At this point, the length of the multi-stage adjustable telescopic structure is fixed, and the length adjustment is complete. Since there are multiple positioning holes, during adjustment, by inserting the positioning pin into different positioning holes, the displacement rod can be fixed at different positions within the mounting cylinder, thereby fixing the multi-stage adjustable telescopic structure to the corresponding length. Therefore, this invention can achieve multi-stage adjustable length of the multi-stage adjustable telescopic structure. Specifically, when the positioning pin is inserted into the positioning hole closest to the connecting rod, the length of the multi-stage adjustable telescopic structure is the shortest; when the positioning pin is inserted into the positioning hole furthest from the connecting rod, the length of the multi-stage adjustable telescopic structure is the longest.

[0007] In this invention, after the length of the telescopic structure is adjusted, if it is necessary to adjust the length of the multi-stage adjustable telescopic structure again, the positioning pin must be disengaged from the positioning hole. At this time, the length of the multi-stage adjustable telescopic structure can be adjusted by moving the displacement rod.

[0008] In this invention, the length of the multi-stage adjustable telescopic structure is determined by the position of the displacement rod inside the mounting cylinder. The position of the displacement rod inside the mounting cylinder is fixed by a positioning pin. The positioning pin is inserted into a positioning hole on the displacement rod to fix it. That is, the fixing structure between the positioning pin and the displacement rod is a rigid structure. It can be seen that the fixing structure used to fix the length of the multi-stage adjustable telescopic structure in this invention will not experience relative slippage or aging failure. In other words, compared with a pneumatic rod, this invention has excellent structural stability and a long service life.

[0009] Furthermore, the end of the displacement rod away from the connecting rod is connected to the end of the mounting cavity via a drive spring, and the drive spring is in a compressed state.

[0010] In this invention, the end of the displacement rod furthest from the connecting rod is connected to the end of the mounting cavity via a drive spring, which is in a compressed state. Therefore, during the adjustment of the length of the multi-stage adjustable telescopic structure, after the positioning pin disengages from the positioning hole, the displacement rod, pushed by the drive spring, will cause the connecting rod to move away from the mounting cylinder. At this time, the length of the multi-stage adjustable telescopic structure will increase. That is, the multi-stage adjustable telescopic structure of this invention can automatically extend during the length adjustment process, providing good ease of use. To reduce the length of the multi-stage adjustable telescopic structure, it is necessary to compress the structure after the positioning pin disengages from the positioning hole, causing the connecting rod to retract into the mounting cylinder. In this case, the length of the multi-stage adjustable telescopic structure will decrease.

[0011] Furthermore, the area on the surface of the displacement rod where the positioning hole is formed is recessed upwards to form a positioning groove, and the positioning hole is located at the top of the positioning groove; the positioning pin has two working positions, namely a first working position and a second working position; when the positioning pin is located at the first working position, the positioning pin is inserted into the positioning hole; when the positioning pin is located at the second working position, the positioning pin is located outside the positioning hole, and the upper end of the positioning pin is located in the positioning groove.

[0012] In this invention, when the positioning pin is in the first working position, it is inserted into the positioning hole, and the displacement rod is fixed in the mounting cylinder, thus fixing the length of the multi-stage adjustable telescopic structure. When the positioning pin is in the second working position, it disengages from the positioning hole, and the length of the multi-stage adjustable telescopic structure can be adjusted by moving the displacement rod. Since the top of the positioning pin is located in the positioning groove when in the second working position, it can still limit the movement of the displacement rod after disengaging from the positioning hole. By abutting against both ends of the positioning groove, the positioning pin restricts the range of motion of the displacement rod, preventing it from shifting and causing it to misalign with the positioning pin. This prevents the positioning pin from abutting against the drive spring or connecting rod, effectively ensuring the reliability of the positioning pin's fixing structure for the positioning rod.

[0013] Furthermore, the limiter also includes a control component, which is drivenly connected to the positioning pin and used to drive the positioning pin to switch back and forth between the first working position and the second working position. The control component includes a control base fixedly disposed on the outer wall of the mounting cylinder, the control base being located below the mounting hole, and a receiving hole corresponding to the mounting hole being opened on the control base. The receiving hole is vertically disposed and communicates with the mounting hole. A base plate is fixedly disposed at the lower end of the receiving hole, and a vertically disposed through hole is formed on the base plate. A vertical rod is inserted into the through hole, which can move up and down reciprocally. The vertical rod is vertically disposed, the upper end of the vertical rod is fixedly connected to the positioning pin, and the lower end of the vertical rod extends downward out of the receiving hole. A first cylindrical spring is also sleeved on the vertical rod, and the two ends of the first cylindrical spring are respectively connected to the positioning pin and the base plate.

[0014] In this invention, the top of the vertical rod is fixedly connected to the positioning pin, and the lower end of the vertical rod extends into a receiving hole. Therefore, by moving the vertical rod up and down at its lower end, the positioning pin can be driven to move up and down, thus controlling the positioning pin and allowing it to switch back and forth between the first and second working positions. Since a first cylindrical spring is sleeved on the vertical rod, and both ends of the first cylindrical spring abut against the positioning pin and the base plate respectively, when adjusting the length of the multi-stage adjustable telescopic structure, after moving the positioning pin to the second working position via the vertical rod, the first cylindrical spring is compressed. Under the action of the first cylindrical spring, the positioning pin tends to move upward. At this time, during the movement of the displacement rod, as long as a positioning hole passes above the positioning pin, the positioning pin will insert into the positioning hole, thereby fixing the displacement rod. That is, the control component can automatically drive the positioning pin to fix the displacement rod, effectively improving the ease of use of the control component.

[0015] Furthermore, because the positioning holes on the displacement rod are arranged along its length, during the process of adjusting the multi-stage adjustable telescopic structure from long to short, and from short to long, the positioning pins will automatically insert into adjacent positioning holes sequentially under the drive of the first cylindrical spring. This means that during the length adjustment of the telescopic rod, it will be fixed step by step, preventing excessive adjustments in a single step and ensuring a smooth length adjustment process. However, it is worth noting that if a large length adjustment is required at once, the positioning pins can be prevented from moving upwards by pulling down the vertical rod, thus preventing them from being inserted into the positioning holes that pass through them step by step.

[0016] Furthermore, the end faces of the positioning groove at both ends along the length of the displacement rod coincide with the side walls of the positioning holes located at both ends of the positioning groove.

[0017] In this invention, the end faces of the positioning groove at both ends coincide with the side walls of the positioning holes located at both ends. Thus, during the movement of the displacement rod, when the displacement rod moves to its maximum displacement position (the end of the positioning groove on the displacement rod abuts against the positioning pin), the positioning pin will be inserted into the corresponding positioning hole. It can be seen that the displacement rod will be fixed when it moves to its maximum displacement position. Compared with the end faces of the positioning groove at both ends not coinciding with the side walls of the positioning holes located at both ends, the displacement rod does not need to move back a certain distance for the positioning pin to fix the displacement rod, which can improve the smoothness of the fixing process of the positioning pin for the displacement rod.

[0018] Furthermore, a horizontal bar is fixedly installed on the portion of the vertical rod extending downwards from the receiving hole. The horizontal bar is horizontally positioned, and a receiving space is formed between the horizontal bar and the base plate. The control assembly also includes a bracket fixedly installed on the control base. A control arm is pivotally connected to the bracket, which can swing up and down. The control arm is elongated and includes a connecting section and a driving section that are fixedly connected to each other. The pivot point between the control arm and the bracket is located at the junction of the connecting section and the driving section. The end of the connecting section away from the driving section forms an insertion end, which is inserted into the receiving space.

[0019] In this invention, the control arm is pivotally connected to the bracket and can swing up and down. The insertion end of the control arm is inserted into the receiving space. Therefore, by pulling up the drive section of the control arm, the insertion end of the control arm can press down the crossbar, thereby driving the positioning pin to move down. When the pull of the drive section is released, the positioning pin will move up under the drive of the first cylindrical spring. That is, the positioning pin can be driven to move up and down by the control arm, thereby controlling the positioning pin and allowing the positioning pin to switch back and forth between the first working position and the second working position.

[0020] Furthermore, the upper and lower surfaces of the insertion end abut against the base plate and the crossbar respectively. At this time, the positioning pin is located in the first working position. The two sides of the insertion end are formed with bent edges, and the lower surfaces of the bent edges are on the same plane to form abutment surfaces. Abutment plates are provided on the bracket corresponding to the abutment surfaces. The abutment plates are located below the abutment surfaces and are used to fit against the abutment surfaces when the connecting section swings downward. When the abutment surfaces fit against the abutment plates, the positioning pin is located in the second working position.

[0021] In this invention, when the positioning pin is in the first working position, the insertion end of the control arm simultaneously abuts against the crossbar and the base plate. At this time, due to the obstruction of the base plate, the insertion end of the control arm cannot be raised, and the positioning pin is located at the top of its travel range. When the positioning pin is in the second working position, the abutting surface on the insertion end abuts against the abutting plate, and the insertion end cannot move further down. At this time, the positioning pin is located at the bottom of its travel range. That is, under the control of the control component, the first and second working positions of the positioning pin are located at the top and bottom of its travel range, respectively. Therefore, when using the control component to control the positioning pin, it is easy to find the first and second working positions of the positioning pin, and it is easy to move the positioning pin to the first and second working positions.

[0022] Furthermore, a second cylindrical spring is also sleeved on the connecting rod. The second cylindrical spring is located inside the mounting cavity, and both ends of the second cylindrical spring are respectively connected to the end of the displacement rod and the end of the mounting cavity. The elastic coefficient of the cylindrical spring is less than that of the driving spring.

[0023] In this invention, the drive spring located between the end of the displacement rod away from the connecting rod and the end of the mounting cavity is in a compressed state. When the positioning pin disengages from the positioning hole, it can push the displacement rod to move in the direction of the connecting rod. At this time, the presence of the second cylindrical spring can play a certain buffering role and reduce the impact between the positioning pin and the displacement rod.

[0024] On the other hand, this utility model also provides a school chair, including legs, a seat and a backrest, the seat being fixedly mounted on the legs, the backrest being rotatably mounted on the legs, and the aforementioned multi-level adjustable telescopic structure connecting the backrest and the legs.

[0025] In this invention, a multi-level adjustable telescopic structure is connected between the backrest and the legs. By adjusting the multi-level adjustable telescopic structure, the rotation range of the backrest relative to the seat can be adjusted, that is, the angle between the backrest and the seat can be adjusted to a suitable angle and fixed, so as to allow the user to lie down and improve the comfort of lying down.

[0026] Furthermore, the chair back is rotatably mounted on the support leg via a mounting bracket. The mounting bracket includes a horizontally arranged mounting rod, both ends of which are rotatably mounted on the support leg via connecting seats. The rotation axis of the mounting rod coincides with its axis. The mounting bracket also includes a connecting arm fixedly mounted on the mounting rod. The connecting arm is perpendicular to the mounting rod, and its top end is fixedly connected to the chair back. A first mounting part is fixedly mounted on the lower end of the mounting rod, and a second mounting part is fixedly mounted on the support leg corresponding to the first mounting part. The second mounting part is located in front of the first mounting part. The multi-stage adjustable telescopic structure is connected between the second mounting part and the first mounting part. The end of the connecting rod of the multi-stage adjustable telescopic structure is hinged to the second mounting part, and the end of the mounting cylinder of the multi-stage adjustable telescopic structure away from the connecting rod is hinged to the first mounting part. Alternatively, the end of the connecting rod of the multi-stage adjustable telescopic structure is hinged to the first mounting part, and the end of the mounting cylinder of the multi-stage adjustable telescopic structure away from the connecting rod is hinged to the second mounting part.

[0027] In this invention, the mounting bracket is rotatably mounted on the support leg, and the chair back is rotatably connected to the support leg by being fixedly connected to the mounting bracket. The chair back is reclined by the rotation of the mounting bracket relative to the support leg.

[0028] In this invention, the first mounting part on the mounting frame is connected to the second mounting part on the support leg through a multi-stage adjustable telescopic structure. That is, the mounting frame is supported by the multi-stage adjustable telescopic structure and fixed to the support leg through the multi-stage adjustable telescopic structure. Therefore, the rotation angle of the mounting frame relative to the support leg is determined by the length of the multi-stage adjustable telescopic structure. Correspondingly, the angle at which the chair back reclines is determined by the length of the multi-stage adjustable telescopic structure. Therefore, during the process of reclining the chair back, the angle at which the chair back reclines can be controlled by controlling the length of the multi-stage adjustable telescopic structure. In other words, this invention can achieve controllability of the reclining angle of the chair back, thereby improving user comfort.

[0029] In this invention, when the chair back is folded down, the positioning pin needs to disengage from the positioning hole. At this time, the multi-stage adjustable telescopic structure is compressed by the first mounting part during the active rotation of the chair back, thus shortening its length as the chair back rotates. Then, the positioning pin is reinserted into the positioning hole, and the length of the multi-stage adjustable telescopic structure is fixed. At this point, the chair back is fixed relative to the support legs, thus completing the folding down of the chair back. Similarly, when the chair back is raised, the positioning pin also needs to disengage from the positioning hole. When the chair back is raised to the appropriate position, the positioning pin is reinserted into the positioning hole, and the length of the multi-stage adjustable telescopic structure is fixed. At this point, the chair back is fixed relative to the support legs, thus completing the raising of the chair back. If a drive spring is connected between the displacement rod and the end of the mounting cavity, after the positioning pin disengages from the positioning hole, the multi-stage adjustable telescopic structure will extend under the elastic force of the drive spring. At this time, the multi-stage adjustable telescopic structure can push the first mounting part to swing backward, causing the chair back to spring back, which can facilitate the raising of the chair back to a certain extent.

[0030] The principle and effects of this utility model will be further explained below with reference to the above technical solution and the accompanying drawings:

[0031] In this invention, the length of the multi-stage adjustable telescopic structure is determined by the position of the displacement rod inside the mounting cylinder. The position of the displacement rod inside the mounting cylinder is fixed by a positioning pin. The positioning pin is inserted into a positioning hole on the displacement rod to fix it. That is, the fixing structure between the positioning pin and the displacement rod is a rigid structure. It can be seen that the fixing structure used to fix the length of the multi-stage adjustable telescopic structure in this invention will not experience relative slippage or aging failure. In other words, compared with a pneumatic rod, this invention has excellent structural stability and a long service life.

[0032] In addition, by connecting the multi-stage adjustable telescopic structure between the support legs and the backrest, the angle at which the backrest reclines can be selectively controlled by selectively controlling the length of the multi-stage adjustable telescopic structure during the process of reclining the backrest. In other words, this utility model can achieve controllability of the reclining angle of the backrest, thereby improving user comfort. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the multi-level adjustable telescopic structure described in an embodiment of the present invention;

[0034] Figure 2 This is a cross-sectional schematic diagram of the multi-level adjustable telescopic structure described in an embodiment of the present utility model;

[0035] Figure 3 This is a diagram showing the usage state of the multi-level adjustable telescopic structure described in this embodiment of the utility model.

[0036] Figure Labels

[0037] 1-Mounting cylinder, 11-Mounting cavity, 2-Displacement rod, 21-Positioning hole, 22-Positioning groove, 3-Connecting rod, 4-Compression spring, 5-Control base, 51-Accommodation hole, 52-Base plate, 53-Vertical rod, 531-Horizontal rod, 54-Bracket, 541-Abutting plate, 55-Positioning pin, 56-First cylindrical spring, 6-Control arm, 61-Drive section, 621-Insertion end, 622-Abutting surface, 7-Second cylindrical spring, 101-Support leg, 102-Seat, 103-Backrest, 104-Mounting rod, 105-Connecting arm, 106-First mounting part, 107-Second mounting part. Detailed Implementation

[0038] To facilitate understanding by those skilled in the art, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0039] A multi-stage adjustable telescopic structure and a school chair using it, such as Figure 1-2 As shown, the device includes a horizontally oriented mounting cylinder 1, with a mounting cavity 11 formed within the cylinder 1 along its length. A displacement rod 2 is slidably disposed within the mounting cavity 11 along the length of the mounting cylinder 1. A connecting rod 3 is fixedly disposed at one end of the displacement rod 2, extending out of the mounting cavity 11 in a direction away from the displacement rod 2. A plurality of positioning holes 21 are formed on the lower surface of the displacement rod 2, arranged along the length of the displacement rod 2. A through mounting hole is formed on the lower surface of the outer side wall of the mounting cylinder 1 corresponding to the positioning holes 21, and the mounting hole is arranged vertically. The device also includes a limiter for fixing the displacement rod 2, the limiter including a positioning pin 55 corresponding to the positioning hole 21, the positioning pin 55 being vertically arranged and slidably inserted into the mounting hole along the mounting hole. Preferably, both ends of the mounting cylinder 1 are sealed to protect the mounting cavity 11 during the use of the multi-stage adjustable telescopic structure. When the connecting rod 3 extends out of the mounting cylinder 1, it is slidably matched with the sealing structure of the mounting cylinder 1 to ensure that the connecting rod 3 can move smoothly relative to the mounting cylinder.

[0040] In this invention, the length of the multi-stage adjustable telescopic structure is its overall length, specifically the length between the end of the connecting rod 3 and the end of the mounting cylinder 1 furthest from the connecting rod 3. The displacement rod 2 is reciprocally slidably disposed within the mounting cavity 11 along the length direction of the mounting cylinder 1. Therefore, by sliding the displacement rod 2 within the mounting cavity 11, the length of the multi-stage adjustable telescopic structure can be adjusted. During the adjustment process, a limiter can be used to fix the position of the displacement rod 2 within the mounting cylinder 1, thereby fixing the length of the multi-stage adjustable telescopic structure and completing the length adjustment of the multi-stage adjustable telescopic structure.

[0041] In this invention, during the length adjustment of the multi-stage adjustable telescopic structure, the limiting device fixes the displacement rod 2 by moving the positioning pin 55 upward until it is inserted into the positioning hole 21, thus fixing the position of the displacement rod 2 within the mounting cylinder 1. At this point, the length of the multi-stage adjustable telescopic structure is fixed, and the length adjustment is complete. Since there are multiple positioning holes 21, during the adjustment process, by inserting the positioning pin 55 into different positioning holes 21, the displacement rod 2 can be fixed at different positions within the mounting cylinder 1, thereby fixing the multi-stage adjustable telescopic structure to the corresponding length. Therefore, this invention can achieve multi-stage adjustable length of the multi-stage adjustable telescopic structure. Specifically, when the positioning pin 55 is inserted into the positioning hole 21 closest to the connecting rod 3, the length of the multi-stage adjustable telescopic structure is the shortest; when the positioning pin 55 is inserted into the positioning hole 21 furthest from the connecting rod 3, the length of the multi-stage adjustable telescopic structure is the longest.

[0042] In this utility model, after the length of the telescopic structure is adjusted, if it is necessary to adjust the length of the multi-stage adjustable telescopic structure again, the positioning pin 55 needs to be disengaged from the positioning hole 21. At this time, the length of the multi-stage adjustable telescopic structure can be adjusted by moving the displacement rod 2.

[0043] In this invention, the length of the multi-stage adjustable telescopic structure is determined by the position of the displacement rod 2 within the mounting cylinder 1. The position of the displacement rod 2 within the mounting cylinder 1 is fixed by the positioning pin 55. The positioning pin 55 is inserted into the positioning hole 21 on the displacement rod 2 to fix the displacement rod 2. That is, the fixing structure between the positioning pin 55 and the displacement rod 2 is a rigid structure. It can be seen that the fixing structure used for fixing the length of the multi-stage adjustable telescopic structure in this invention will not experience relative slippage or aging failure. In other words, compared with the pneumatic rod, this invention has excellent structural stability and a long service life.

[0044] In one embodiment, the end of the displacement rod 2 away from the connecting rod 3 is connected to the end of the mounting cavity 11 via a drive spring, and the drive spring is in a compressed state.

[0045] In this embodiment, the end of the displacement rod 2 away from the connecting rod 3 is connected to the end of the mounting cavity 11 via a drive spring, and the drive spring is in a compressed state. Therefore, during the adjustment of the length of the multi-stage adjustable telescopic structure, after the positioning pin 55 disengages from the positioning hole 21, the displacement rod 2 will be pushed by the drive spring to move the connecting rod 3 away from the mounting cylinder 1. At this time, the length of the multi-stage adjustable telescopic structure will increase. That is, the multi-stage adjustable telescopic structure of this utility model can automatically extend during the length adjustment process, which has good ease of use. If the length of the multi-stage adjustable telescopic structure is to be reduced, the multi-stage adjustable telescopic structure needs to be compressed after the positioning pin 55 disengages from the positioning hole 21, so that the connecting rod 3 retracts back into the mounting cylinder 1. At this time, the length of the multi-stage adjustable telescopic structure will decrease.

[0046] In one embodiment, the area on the surface of the displacement rod 2 where the positioning hole 21 is formed is recessed upwards to form a positioning groove 22, and the positioning hole 21 is located at the top of the positioning groove 22; the positioning pin 55 has two working positions, namely a first working position and a second working position; when the positioning pin 55 is located at the first working position, the positioning pin 55 is inserted into the positioning hole 21; when the positioning pin 55 is located at the second working position, the positioning pin 55 is located outside the positioning hole 21, and the upper end of the positioning pin 55 is located in the positioning groove 22.

[0047] In this embodiment, when the positioning pin 55 is in the first working position, it is inserted into the positioning hole 21, and the displacement rod 2 is fixed in the mounting cylinder 1, thus fixing the length of the multi-stage adjustable telescopic structure. When the positioning pin 55 is in the second working position, it disengages from the positioning hole 21, and the length of the multi-stage adjustable telescopic structure can be adjusted by moving the displacement rod 2. Since the top of the positioning pin 55 is located in the positioning groove 22 when it is in the second working position, it can still limit the movement of the displacement rod 2 after disengaging from the positioning hole 21. By abutting against both ends of the positioning groove 22, the positioning pin 55 restricts the movement range of the displacement rod 2, preventing it from shifting away from the positioning pin 55. This avoids the positioning pin 55 abutting against the drive spring or connecting rod 3, effectively ensuring the reliability of the positioning pin 55's fixing structure for the positioning rod.

[0048] In one embodiment, the limiter further includes a control component, which is drivenly connected to the positioning pin 55 and used to drive the positioning pin 55 to switch back and forth between the first working position and the second working position. The control component includes a control base 5 fixedly disposed on the outer wall of the mounting cylinder 1. The control base 5 is located below the mounting hole, and the control base 5 has a receiving hole 51 corresponding to the mounting hole. The receiving hole 51 is vertically disposed and communicates with the mounting hole. A base plate 52 is fixedly disposed at the lower end of the receiving hole 51. A vertically disposed through hole is formed on the base plate 52. A vertical rod 53 is inserted into the through hole and can be moved up and down. The vertical rod 53 is vertically disposed. The upper end of the vertical rod 53 is fixedly connected to the positioning pin 55, and the lower end of the vertical rod 53 extends downward out of the receiving hole 51. A first cylindrical spring 56 is also sleeved on the vertical rod 53. The two ends of the first cylindrical spring 56 are respectively connected to the positioning pin 55 and the base plate 52.

[0049] In this embodiment, the top end of the vertical rod 53 is fixedly connected to the positioning pin 55, and the lower end of the vertical rod 53 extends into the receiving hole 51. Therefore, by moving the vertical rod 53 up and down by moving the lower end of the vertical rod 53, the positioning pin 55 can be driven to move up and down, thereby realizing the control of the positioning pin 55 and allowing the positioning pin 55 to switch back and forth between the first working position and the second working position. Since the vertical rod 53 is fitted with a first cylindrical spring 56, and the two ends of the first cylindrical spring 56 abut against the positioning pin 55 and the base plate 52 respectively, when it is necessary to adjust the length of the multi-stage adjustable telescopic structure, after the positioning pin 55 is moved to the second working position by the vertical rod 53, the first cylindrical spring 56 will be compressed, and the positioning pin 55 will have an upward tendency under the action of the first cylindrical spring 56. At this time, during the process of moving the displacement rod 2, as long as the positioning hole 21 passes above the positioning pin 55, the positioning pin 55 will be inserted into the positioning hole 21, thereby fixing the displacement rod 2. That is, the control component can automatically drive the positioning pin 55 to fix the displacement rod 2, which can effectively improve the ease of use of the control component.

[0050] Furthermore, since the positioning holes 21 on the displacement rod 2 are arranged along its length, during the process of adjusting the multi-stage adjustable telescopic structure from long to short, and from short to long, the positioning pins 55 will automatically insert into adjacent positioning holes 21 sequentially under the drive of the first cylindrical spring 56. That is, during the length adjustment of the telescopic rod, the telescopic rod will be fixed step by step, preventing excessive adjustment in one step and ensuring a smooth length adjustment process for the multi-stage adjustable telescopic structure. However, it is worth noting that if a large length adjustment is required at once, the positioning pins 55 can be prevented from being inserted into the positioning holes 21 that pass through it by pulling down the vertical rod 53 to prevent the positioning pins 55 from moving upward.

[0051] In one embodiment, the end faces of the two ends of the positioning groove 22 along the length direction of the displacement rod 2 coincide with the side walls of the positioning holes 21 located at both ends of the positioning groove 22.

[0052] In this embodiment, the end faces of the positioning groove 22 at both ends coincide with the side walls of the positioning holes 21 located at both ends. Thus, during the movement of the displacement rod 2, when the displacement rod 2 moves to its maximum displacement position (the end of the positioning groove 22 on the displacement rod 2 abuts against the positioning pin 55), the positioning pin 55 will be inserted into the corresponding positioning hole 21. It can be seen that the displacement rod 2 will be fixed when it moves to its maximum displacement position. Since the end faces of the positioning groove 22 at both ends do not coincide with the side walls of the positioning holes 21 located at both ends, the displacement rod 2 does not need to move back a certain distance so that the positioning pin 55 can fix the displacement rod 2. This can improve the smoothness of the fixing process of the positioning pin 55 for the displacement rod 2.

[0053] In one embodiment, a horizontal bar 531 is fixedly installed on the portion of the vertical bar 53 extending downward from the receiving hole 51. The horizontal bar 531 is horizontally positioned, and a receiving space is formed between the horizontal bar 531 and the base plate 52. The control assembly also includes a bracket 54 fixedly installed on the control base 5. A control arm 6 is pivotally connected to the bracket 54, which can swing up and down. The control arm 6 is elongated and includes a connecting section and a driving section 61 that are fixedly connected to each other. The pivot point between the control arm 6 and the bracket 54 is located at the junction of the connecting section and the driving section 61. An insertion end 621 is formed at the end of the connecting section away from the driving section, and the insertion end 621 is inserted into the receiving space.

[0054] In this embodiment, the control arm 6 is pivotally connected to the bracket 54 and can swing up and down. The insertion end 621 on the control arm 6 is inserted into the receiving space. Therefore, by pulling up the drive section 61 of the control arm 6, the insertion end 621 of the control arm 6 can press down the crossbar 531, thereby driving the positioning pin 55 to move down. After releasing the pull on the drive section 61, the positioning pin 55 will move up under the drive of the first cylindrical spring 56. That is, the control arm 6 can drive the positioning pin 55 to move up and down, thereby controlling the positioning pin 55 and allowing the positioning pin 55 to switch back and forth between the first working position and the second working position.

[0055] In one embodiment, the upper and lower surfaces of the insertion end 621 abut against the base plate 52 and the crossbar 531, respectively. At this time, the positioning pin 55 is located in the first working position. The two sides of the insertion end 621 are formed with bent edges, and the lower surfaces of the bent edges are on the same plane to form an abutment surface 622. The bracket 54 is provided with an abutment plate 541 corresponding to the abutment surface 622. The abutment plate 541 is located below the abutment surface 622 and is used to fit against the abutment surface 622 when the connecting section swings downward. When the abutment surface 622 fits against the abutment plate 541, the positioning pin 55 is located in the second working position.

[0056] In this embodiment, when the positioning pin 55 is in the first working position, the insertion end 621 of the control arm 6 simultaneously abuts against the crossbar 531 and the base plate 52. At this time, due to the obstruction of the base plate 52, the insertion end 621 of the control arm 6 cannot be raised, and the positioning pin 55 is located at the top of its travel range. When the positioning pin 55 is in the second working position, the abutting surface 622 on the insertion end 621 abuts against the abutting plate 541, and the insertion end 621 cannot continue to move downward. At this time, the positioning pin 55 is located at the bottom of its travel range. That is, under the control of the control component, the first working position and the second working position of the positioning pin 55 are located at the top and bottom of its travel range, respectively. Therefore, when using the control component to control the positioning pin 55, it is convenient to find the first working position and the second working position of the positioning pin 55, and it is convenient to move the positioning pin 55 to its first working position and the second working position.

[0057] In one embodiment, a second cylindrical spring 7 is also sleeved on the connecting rod 3. The second cylindrical spring 7 is located inside the mounting cavity 11, and both ends of the second cylindrical spring 7 are respectively connected to the end of the displacement rod 2 and the end of the mounting cavity 11. The elastic coefficient of the cylindrical spring is less than that of the driving spring.

[0058] In this embodiment, the drive spring located between the end of the displacement rod 2 away from the connecting rod 3 and the end of the mounting cavity 11 is in a compressed state. When the positioning pin 55 is disengaged from the positioning hole 21, it can push the displacement rod 2 to move in the direction of the connecting rod 3. At this time, the presence of the second cylindrical spring 7 can play a certain buffering role and reduce the impact between the positioning pin 55 and the displacement rod 2.

[0059] On the other hand, this utility model also provides a school chair, such as Figure 3 As shown, the chair includes a leg 101, a seat 102, and a backrest 103. The seat 102 is fixedly mounted on the leg 101, and the backrest 103 is rotatably mounted on the leg 101. The backrest 103 and the leg 101 are connected by the aforementioned multi-stage adjustable telescopic structure.

[0060] In this invention, a multi-level adjustable telescopic structure is connected between the backrest 103 and the support leg 101. By adjusting the multi-level adjustable telescopic structure, the rotation range of the backrest 103 relative to the seat 102 can be adjusted, that is, the angle between the backrest 103 and the seat 102 can be adjusted to a suitable angle and fixed, so as to enable the user to lie down and improve the comfort of lying down.

[0061] In one embodiment, the chair back 103 is rotatably mounted on the support leg 101 via a mounting bracket. The mounting bracket includes a horizontally arranged mounting rod 104, both ends of which are rotatably mounted on the support leg 101 via connecting seats. The rotation axis of the mounting rod 104 coincides with its axis. The mounting bracket also includes a connecting arm 105 fixedly mounted on the mounting rod 104. The connecting arm 105 is perpendicular to the mounting rod 104, and its top end is fixedly connected to the chair back 103. A first mounting portion 106 is fixedly mounted on the lower end of the mounting rod 104, and a corresponding mounting portion 106 is mounted on the support leg 101. A second mounting part 107 is fixedly provided on the first mounting part 106. The second mounting part 107 is located in front of the first mounting part 106. The multi-stage adjustable telescopic structure is connected between the second mounting part 107 and the first mounting part 106. The end of the connecting rod 3 of the multi-stage adjustable telescopic structure is hinged to the second mounting part 107. The end of the mounting cylinder 1 of the multi-stage adjustable telescopic structure away from the connecting rod 3 is hinged to the first mounting part 106. Alternatively, the end of the connecting rod 3 of the multi-stage adjustable telescopic structure is hinged to the first mounting part 106, and the end of the mounting cylinder 1 of the multi-stage adjustable telescopic structure away from the connecting rod 3 is hinged to the second mounting part 107.

[0062] In this embodiment, the mounting bracket is rotatably mounted on the support leg 101, and the backrest 103 is rotatably connected to the support leg 101 by being fixedly connected to the mounting bracket. The backrest 103 is reclined backward by the rotation of the mounting bracket relative to the support leg 101.

[0063] In this embodiment, the first mounting part 106 on the mounting frame is connected to the second mounting part 107 on the support leg 101 through a multi-stage adjustable telescopic structure. That is, the mounting frame is supported by the multi-stage adjustable telescopic structure and fixed to the support leg 101 through the multi-stage adjustable telescopic structure. Therefore, the rotation angle of the mounting frame relative to the support leg 101 is determined by the length of the multi-stage adjustable telescopic structure. Correspondingly, the angle at which the backrest 103 reclines is determined by the length of the multi-stage adjustable telescopic structure. Therefore, during the process of reclining the backrest 103, the angle at which the backrest 103 reclines can be controlled by controlling the length of the multi-stage adjustable telescopic structure. That is, this utility model can achieve the controllability of the reclining angle of the backrest 103, thereby improving the comfort of use.

[0064] In this embodiment, when the chair back 103 is folded down, the positioning pin 55 needs to be disengaged from the positioning hole 21. At this time, the multi-stage adjustable telescopic structure can be compressed by the first mounting part 106 during the active rotation of the chair back 103, thereby shortening its length as the chair back 103 rotates. Then, the positioning pin 55 is reinserted into the positioning hole 21, and the length of the multi-stage adjustable telescopic structure is fixed. At this time, the chair back 103 is fixed relative to the support leg 101, thus completing the folding down of the chair back 103. Similarly, when lifting the backrest 103, the positioning pin 55 needs to disengage from the positioning hole 21. When the backrest 103 is lifted to the appropriate position, the positioning pin 55 is reinserted into the positioning hole 21, and the length of the multi-stage adjustable telescopic structure is fixed. At this time, the backrest 103 is fixed relative to the support leg 101, completing the lifting of the backrest 103. If a drive spring is connected between the displacement rod 2 and the end of the mounting cavity 11, the multi-stage adjustable telescopic structure will extend under the elastic force of the drive spring after the positioning pin 55 disengages from the positioning hole 21. At this time, the multi-stage adjustable telescopic structure can push the first mounting part 106 to swing backward, causing the backrest 103 to rebound, which can facilitate the lifting of the backrest 103 to a certain extent.

[0065] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they 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 these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A multi-stage adjustable telescopic structure, characterized in that, The device includes a horizontally oriented mounting cylinder with a mounting cavity formed along its length. A displacement rod is slidably mounted within the mounting cavity along the length of the mounting cylinder. A connecting rod is fixedly mounted at one end of the displacement rod, extending out of the mounting cavity in a direction away from the displacement rod. A plurality of positioning holes are formed on the lower surface of the displacement rod, arranged along its length. A through mounting hole is formed on the lower surface of the outer wall of the mounting cylinder corresponding to the positioning holes, and the mounting holes are vertically oriented. The device also includes a limiter for fixing the displacement rod, comprising a positioning pin corresponding to the positioning hole. The positioning pin is vertically oriented and slidably inserted into the mounting hole.

2. The multi-stage adjustable telescopic structure according to claim 1, characterized in that, The end of the displacement rod away from the connecting rod is connected to the end of the mounting cavity via a drive spring, and the drive spring is in a compressed state.

3. The multi-stage adjustable telescopic structure according to claim 2, characterized in that, The area on the surface of the displacement rod with the positioning hole is recessed upwards to form a positioning groove, and the positioning hole is located at the top of the positioning groove; the positioning pin has two working positions, namely a first working position and a second working position; when the positioning pin is located at the first working position, the positioning pin is inserted into the positioning hole; when the positioning pin is located at the second working position, the positioning pin is located outside the positioning hole, and the upper end of the positioning pin is located in the positioning groove.

4. The multi-stage adjustable telescopic structure according to claim 3, characterized in that, The limiter further includes a control component, which is drivenly connected to the positioning pin and used to drive the positioning pin to switch back and forth between the first working position and the second working position. The control component includes a control base fixedly disposed on the outer wall of the mounting cylinder, the control base being located below the mounting hole, and a receiving hole corresponding to the mounting hole being opened on the control base. The receiving hole is vertically disposed and communicates with the mounting hole. A base plate is fixedly disposed at the lower end of the receiving hole, and a vertically disposed through hole is formed on the base plate. A vertical rod is inserted into the through hole, which can be moved up and down. The vertical rod is vertically disposed, the upper end of the vertical rod is fixedly connected to the positioning pin, and the lower end of the vertical rod extends downward out of the receiving hole. A first cylindrical spring is also sleeved on the vertical rod, and the two ends of the first cylindrical spring are respectively connected to the positioning pin and the base plate.

5. The multi-stage adjustable telescopic structure according to claim 4, characterized in that, The end faces of the positioning groove at both ends along the length of the displacement rod coincide with the side walls of the positioning holes located at both ends of the positioning groove.

6. The multi-stage adjustable telescopic structure according to claim 4 or 5, characterized in that, A horizontal bar is fixedly installed on the portion of the vertical rod extending downwards from the receiving hole. The horizontal bar is horizontally positioned, and a receiving space is formed between the horizontal bar and the base plate. The control assembly also includes a bracket fixedly installed on the control base. A control arm is pivotally connected to the bracket, which can swing up and down. The control arm is elongated and includes a connecting section and a driving section that are fixedly connected to each other. The pivot point between the control arm and the bracket is located at the junction of the connecting section and the driving section. The end of the connecting section away from the driving section forms an insertion end, which is inserted into the receiving space.

7. The multi-stage adjustable telescopic structure according to claim 6, characterized in that, The upper and lower surfaces of the insertion end abut against the base plate and the crossbar, respectively. At this time, the positioning pin is located in the first working position. The two sides of the insertion end are formed with bent edges. The lower surfaces of the bent edges are on the same plane to form abutment surfaces. Abutment plates are provided on the bracket corresponding to the abutment surfaces. The abutment plates are located below the abutment surfaces and are used to fit against the abutment surfaces when the connecting section swings downward. When the abutment surfaces fit against the abutment plates, the positioning pin is located in the second working position.

8. The multi-stage adjustable telescopic structure according to claim 2, characterized in that, A second cylindrical spring is also sleeved on the connecting rod. The second cylindrical spring is located inside the mounting cavity, and both ends of the second cylindrical spring are respectively connected to the end of the displacement rod and the end of the mounting cavity. The elastic coefficient of the cylindrical spring is less than that of the driving spring.

9. A school chair, characterized in that, The chair includes a leg, a seat, and a backrest. The seat is fixedly mounted on the leg, and the backrest is rotatably mounted on the leg. A multi-stage adjustable telescopic structure as described in any one of claims 1-8 connects the backrest and the leg.

10. A school chair according to claim 9, characterized in that, The chair back is rotatably mounted on the support leg via a mounting bracket. The mounting bracket includes a horizontally arranged mounting rod, both ends of which are rotatably mounted on the support leg via connecting seats. The rotation axis of the mounting rod coincides with its own axis. The mounting bracket also includes a connecting arm fixedly mounted on the mounting rod. The connecting arm is perpendicular to the mounting rod, and its top end is fixedly connected to the chair back. A first mounting part is fixedly mounted on the lower end of the mounting rod, and a second mounting part is fixedly mounted on the support leg corresponding to the first mounting part. The second mounting part is located in front of the first mounting part. A multi-stage adjustable telescopic structure is connected between the second mounting part and the first mounting part. The end of the connecting rod of the multi-stage adjustable telescopic structure is hinged to the second mounting part, and the end of the mounting cylinder of the multi-stage adjustable telescopic structure away from the connecting rod is hinged to the first mounting part. Alternatively, the end of the connecting rod of the multi-stage adjustable telescopic structure is hinged to the first mounting part, and the end of the mounting cylinder of the multi-stage adjustable telescopic structure away from the connecting rod is hinged to the second mounting part.

Images