Chair back rail transfer mechanism and seat

Abstract

The utility model provides a chair back orbital transfer mechanism and a seat, which comprise a chair back component and an orbital transfer guide component, a first linkage piece and a second linkage piece which are spaced up and down in the orbital transfer guide component are hinged between a back bracket and a backrest component, so that the orbital transfer guide component and the chair back component form a four-bar linkage structure; when the chair is subjected to an external force that the back of a seated person leans backwards, the chair back assembly correspondingly leans backwards and triggers the backrest assembly, so that the backrest assembly can move forwards and downwards from a higher position to a lower position while leaning backwards to an inclined state along with the chair back assembly, and the phenomenon that the backrest assembly directly rubs the back is avoided; and meanwhile, the backrest assembly forms self-adaptive support on the back sliding downwards.

Description

Technical Field

[0001] The utility model relates to the field of seats, in particular to a seat back track changing mechanism and a seat. Background Art

[0002] Chairs are an indispensable tool for home life and office environment. As people's living standards improve, they have higher and higher comfort requirements for chairs. For example, in addition to normal sitting, the backrests of some office chairs can also be rotated backwards, making the office chair have the function of a reclining chair.

[0003] For some reclining office chairs, a locking switch is provided on the chassis of the chair. With the control of the locking switch, the chair back can be either uprighted to maintain a support state, or it can be tilted back and rotated around the chassis and then switched to a tilted back state. When the chair back rotates back, the entire chair back falls backward. As a result, the front-to-back distance between the chair back and the seat will change when the chair back is tilted back. When the position of the seat remains unchanged, the chair back and the user's back will undergo relative displacement and friction, causing discomfort. Thus, the so-called "back rubbing" problem occurs. The chair back of a conventional chair can only slide longitudinally to adjust the chair back height, but the chair back cannot slide front and back, which results in the chair back not being able to effectively fit the user's back during actual use.

[0004] In order to achieve the front and back adjustment of the chair back, the existing chair back is designed with a "double back" structure, that is, the upper and lower parts of the chair back are split structures, and the lower part of the chair back can be adjusted forward and backward. When the entire chair back is reclined, the chair back can be adjusted forward and backward to provide stable support for the back. Although this design solves the problem of front and rear support for the back, since the adjusted chair back is still in a fixed state, the "back rubbing" problem still exists when the chair back is reclined. Therefore, this type of chair cannot provide adaptive support for the back when the chair back falls backward. Summary of the invention

[0005] In order to solve the above-mentioned technical problems, the purpose of the utility model is to provide a chair back track changing mechanism, by hingedly connecting the first and second linkage members spaced apart from each other in the track changing guide assembly between the back bracket and the backrest assembly, so that the track changing guide assembly and the chair back assembly form a four-bar structure. Under the action of external force, the backrest assembly can slide downward with the back under the guidance of the track changing guide assembly, thereby avoiding the backrest assembly directly rubbing the back.

[0006] A chair is further provided, in which a chair back track changing mechanism is arranged at the rear end of the seat. When an external force is applied to the seat occupant's back to lean back, the chair back assembly will lean back accordingly and trigger the backrest assembly, so that the backrest assembly can move from a higher position forward and downward to a lower position as the chair back assembly leans back to an inclined state, thereby forming an adaptive support for the back that slides downward.

[0007] The technical solution of the utility model is achieved in this way:

[0008] A chair back track changing mechanism, comprising:

[0009] A chair back assembly, comprising a back support and a backrest assembly disposed in front of the back support;

[0010] The track change guide assembly is arranged between the back support and the backrest assembly, and includes a first linkage member and a second linkage member spaced apart from each other in an upper and lower direction. The front and rear ends of the first linkage member are directly hinged to the backrest assembly and the back support respectively, and the front and rear ends of the second linkage member are directly hinged to the backrest assembly and the back support, so that a four-link structure is formed among the back support, the backrest assembly, the first linkage member, and the second linkage member.

[0011] In the initial state, the backrest assembly is in a higher position; when the backrest assembly is triggered by a downward external force, it moves downward under the guidance of the track change guide assembly to switch to a lower position.

[0012] Preferably, in the initial state, the first linkage member extends forward or downward and is hinged to the upper end of the backrest assembly, and the second linkage member extends forward and upward and is hinged to the lower end of the backrest assembly, thereby forming a trapezoidal four-bar linkage structure with a narrow front and a wide rear between the track change guide assembly and the seat back assembly;

[0013] When the backrest assembly is triggered by a downward external force, the trapezoidal four-bar linkage structure deforms and drives the backrest assembly to move downward. At this time, the first linkage member rotates downward and drives the upper end of the backrest assembly to lean back, and the second linkage member rotates downward and drives the lower end of the backrest assembly to move forward; the forward-moving backrest assembly can form a chasing-back support for the back to avoid the phenomenon of the back being suspended in the air.

[0014] Preferably, the first linkage comprises a first rotating part hinged to the back bracket, a first rotating arm being connected to the first rotating part being symmetrical with respect to the left and right sides, the second linkage comprises a second rotating part hinged to the back bracket, a second rotating arm being connected to the second rotating part being symmetrical with respect to the left and right sides, the front ends of the first rotating arm and the second rotating arm being hinged to corresponding positions of the backrest assembly, thereby enabling the track changing guide assembly to form a rotating support for both the left and right sides of the backrest assembly; and forming a four-bar structure at both the left and right ends of the backrest assembly, so that the left and right ends of the backrest assembly can move up and down simultaneously.

[0015] Preferably, the length of the first rotating arm is smaller than that of the second rotating arm; the longer second rotating arm has a larger rotating radius, which can increase the degree of forward movement of the lower end of the backrest assembly, thereby amplifying the chasing effect of the seat back track changing mechanism.

[0016] Preferably, an elastic member is provided between the chair back assembly and the track-changing guide assembly, which can reset the four-bar structure after deformation. When the backrest assembly is triggered and moves downward under the action of a downward external force, the elastic member is deformed; when the external force is removed, the track-changing guide assembly can rotate upward relative to the back support under the action of the elastic member to reset the backrest assembly upward; the elastic member can provide elastic force for the deformation of the four-bar structure, so that the backrest assembly can automatically reset upward after moving downward.

[0017] Preferably, the four-bar linkage structure formed between the track change guide assembly and the seat back assembly has four hinged ends, and the elastic member is a torsion spring arranged at at least one hinged end position; the torsion spring can provide elastic deformation force for the four-bar linkage structure, and at the same time, the torsion spring occupies a small space, so it is easy to hide in the hinged end formed by the track change guide assembly and the seat back assembly, and will not affect the appearance of the entire seat back assembly.

[0018] Preferably, a protruding rotation limit tooth is provided on the outer wall of the second rotating part, and the rotation limit tooth can rotate synchronously with the second rotating part; a limiting surface facing the rotation limit tooth is provided at the front end of the back bracket; when the backrest assembly moves downward into place, the rotation limit tooth abuts against the limiting surface; when the backrest assembly is reset upward, the rotation limit tooth separates from the limiting surface; the design of the rotation limit tooth and the limiting surface can avoid excessive deformation of the four-bar structure, so that the backrest assembly can still provide stable support for the back after rotating downward.

[0019] Preferably, it also includes a locking component arranged between the rotation limit tooth and the limit surface, and the locking component includes a locking slider; when the backrest component moves upward to the initial position, an empty area is formed between the rotation limit tooth and the limit surface, and the locking slider can fill or make room for the empty area by sliding itself, so that the rotation limit tooth abuts against the locking slider and is limited or leaves a rotation space, thereby allowing the locking slider to lock or unlock the downward movement of the backrest component; the locking component enables the track change guide component to be locked or unlocked according to actual needs, thereby expanding the application range of the chair back.

[0020] Preferably, the locking assembly also includes a control wrench, which includes a handle and a control part. The junction of the control part and the handle forms a rotating part rotatably connected to the back bracket, and a plug column is provided at the end of the control part away from the rotating part; a waist-shaped groove is provided on the locking slider, and the plug column is slidably connected in the waist-shaped groove; the handle is rotated to drive the locking slider to slide to reach the corresponding position; the control wrench is easy to be turned by external force, so that the user can control the backrest assembly to switch freely between the locked state and the unlocked state.

[0021] Preferably, the back support is provided with a slide groove which is recessed inwardly, and the locking slider slides in the slide groove. A fixing seat is provided at the opening of the slide groove, and the fixing seat restricts the locking slider in the slide groove, thereby preventing the locking slider from escaping from the slide groove.

[0022] Preferably, a guide groove extending along the sliding direction of the locking slider is provided on the end surface of the fixed seat facing the locking slider, and a guide rail is correspondingly provided on the end surface of the locking slider facing the fixed seat, and the guide rail is slidably connected in the guide groove; the guide rail and the guide groove cooperate to play a sliding guiding role for the locking slider, so that the locking slider slides in a predetermined direction.

[0023] Preferably, an arc groove corresponding to the rotation trajectory of the control part is provided on the fixed seat, and the arc groove includes a starting end and an ending end. The column passes through the arc groove and is inserted into the waist-shaped groove, and switches between the starting end and the ending end under the linkage of the rotating part to drive the locking slider to fill or vacate the empty area; when the arc groove avoids the rotation trajectory of the control part, the starting end and the ending end can limit the swing range of the control part, so that the locking slider slides within a reasonable range.

[0024] A seat is further provided, including a seat and the seat back track changing mechanism, wherein the lower end of the back support is rotatably connected to the rear end of the seat, and the seat back assembly can be tilted back to a tilted state under the action of an external force while triggering the backrest assembly, so that the backrest assembly moves from a higher position to a lower position forward and downward.

[0025] The principle of the utility model using the above technical solution is:

[0026] The utility model provides a chair back track changing mechanism, which forms a four-link structure with the track changing guide assembly and the chair back assembly by hingedly connecting a first linking member and a second linking member spaced apart from each other in a track changing guide assembly between a back support and a backrest assembly, so that the track changing guide assembly and the chair back assembly can move up and down relative to the back support through the four-link principle.

[0027] A chair is further provided, in which a chair back track changing mechanism is arranged at the rear end of the seat. When an external force is applied to the seat occupant's back to lean back, the chair back assembly will lean back accordingly and trigger the backrest assembly, so that the backrest assembly can move from a higher position forward and downward to a lower position while the chair back assembly leans back to a tilted state.

[0028] The beneficial effects of the utility model using the above technical solution are:

[0029] 1. When the back of the seated person is against the backrest assembly, the friction between the back and the backrest assembly can give the backrest assembly a downward external force, causing the four-bar structure formed by the track-changing guide assembly and the chair back assembly to deform. At this time, under the guidance of the track-changing guide assembly, the entire backrest assembly will move with the downward movement of the back, avoiding the occurrence of the "back rubbing" problem.

[0030] 2. Install the chair back track changing mechanism at the rear end of the seat. When the occupant leans back, the chair back assembly will recline to a tilted state. During the reclining process, the back will move forward and downward. The friction between the back and the backrest assembly will also cause the backrest assembly to move forward and downward, thereby enabling the backrest assembly to achieve adaptive tracking support for the back and effectively protect the back. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of the backrest assembly when it is not moved downward;

[0032] Figure 2 is a schematic diagram of the backrest assembly after being moved downward;

[0033] Figure 3 This is an exploded view of the seat back track changing mechanism;

[0034] Figure 4 This is an exploded view of the locking assembly;

[0035] Figure 5 is an exploded diagram of the second linkage and the torsion spring;

[0036] Figure 6 is an enlarged view of the receiving groove on the back support;

[0037] Figure 7 is an enlarged view of the locking assembly installed in the receiving groove;

[0038] Figure 8 It is an enlarged view of the abutment between the rotation limit tooth and the limit surface;

[0039] Figure 9a It is a structural principle diagram of the hinged connection between the track change assembly and the back support and backrest assembly;

[0040] Figure 9b The schematic diagram is a schematic diagram of the backrest assembly moving forward and downward under the guidance of the track change assembly;

[0041] Fig.10a The structural diagram of the seat back track changing mechanism connected to the seat seat;

[0042] Fig.10b It is a schematic diagram of the structure in which the backrest assembly slides downward when the back support reclines;

[0043] Fig.11a Structural diagram of inserting the plug-in column into the waist-shaped groove on the control wrench;

[0044] Fig.11b This is the schematic diagram before the locking slider enters the empty area;

[0045] Fig.11c This is the schematic diagram after the locking slider enters the empty area;

[0046] Fig.12 The schematic diagram of the backrest assembly moving forward and downward driven by the track changing assembly in Example 2;

[0047] The reference numerals are: 1-back support, 2-backrest assembly, 3-first linkage member, 4-second linkage member, 5-torsion spring, 6-locking assembly, 7-rotating shaft, 8-seat, 11-second joint, 12-first joint, 13-torsion spring slot, 14-accommodating slot, 15-rotation support seat, 31-first rotating part, 32-first rotating arm, 41-second rotating part, 42-second rotating arm, 43-rotation limiting tooth, 44-jack, 61-control wrench, 62-fixed seat, 63-locking slider, 141-slideway, 142-installation slot, 611-insertion column, 612-rotating member, 613-wrench, 614-control part, 621-arc groove, 621a-starting end, 621b-terminating end, 622-guide groove, 631-waist groove, 632-guide rail, 633-limiting end surface, a-first hinge point, b-second hinge point, c-third hinge point. d-fourth hinge point, e-empty area, s-limiting surface. DETAILED DESCRIPTION

[0048] In order to more clearly understand the above-mentioned purpose, features and advantages of the utility model, the utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0049] In the description of the present invention, the term "at least one" refers to one or more than one, unless otherwise clearly defined. The terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0050] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0051] The utility model has multiple embodiments, and the specific implementation methods are as follows:

[0052] Example 1: Figure 1-11c As shown, the utility model provides a chair back track changing mechanism.

[0053] A chair back assembly, comprising a back support 1 and a backrest assembly 2 arranged in front of the back support 1;

[0054] The track change guide assembly is arranged between the back support 1 and the backrest assembly 2, and includes a first linkage member 3 and a second linkage member 4 arranged at intervals in the upper and lower parts. The front and rear ends of the first linkage member 3 are directly hinged to the backrest assembly 2 and the back support 1 respectively, and the front and rear ends of the second linkage member 4 are directly hinged to the backrest assembly 2 and the back support 1, so that a four-link structure is formed between the back support 1, the backrest assembly 2, the first linkage member 3, and the second linkage member 4;

[0055] In the initial state, the backrest assembly 2 is in a higher position; when the backrest assembly 2 is triggered by a downward external force, it moves downward under the guidance of the track change guide assembly to switch to a lower position.

[0056] like Figure 1-2 As shown, in the initial state, the first linkage member 3 extends forward or downward and is hinged to the upper end of the backrest assembly 2, and the second linkage member 4 extends forward and upward and is hinged to the lower end of the backrest assembly 2, thereby forming a trapezoidal four-link structure with a narrow front and a wide rear between the track change guide assembly and the seat back assembly; specifically, the rear end of the first linkage member 3 and the rear end of the second linkage member 4 are hinged to the back support 1, thereby forming a first hinge point a and a second hinge point b at the upper and lower ends of the back support 1 respectively; the first linkage member 3 extends forward or downward and is hinged to the upper end of the backrest assembly 2, and the second linkage member 4 extends forward and upward and is hinged to the lower end of the backrest assembly 2, thereby forming a third hinge point c and a fourth hinge point b at the upper and lower ends of the backrest assembly 2 respectively. Hinge point d; the distance between the third hinge point c and the fourth hinge point d is smaller than the distance between the first hinge point a and the second hinge point b, thereby forming a trapezoidal four-bar linkage structure that is narrow in front and wide in the back between the track change guide assembly and the chair back assembly; when the backrest assembly 2 is triggered by the downward external force, the trapezoidal four-bar linkage structure deforms and drives the backrest assembly 2 to move downward. At this time, the first linkage member 3 rotates downward, causing the third hinge point c to gradually approach the back bracket 1, and drives the upper end of the backrest assembly 2 to lean back, and the second linkage member 4 rotates downward, causing the fourth hinge point d to gradually move away from the back bracket 1, and drives the lower end of the backrest assembly 2 to move forward; the forward-moving backrest assembly 2 can form a chasing-back support for the back to avoid the phenomenon of the back being suspended in the air.

[0057] like Figure 3 , Figure 5As shown, in order to keep the backrest assembly 2 stable when moving downward, the first linkage 3 includes a first rotating part 31 hinged to the back support 1, and the first rotating part 31 is connected to a left-right symmetrical first rotating arm 32, the second linkage 4 includes a second rotating part 41 hinged to the back support 1, and the second rotating part 41 is connected to a left-right symmetrical second rotating arm 42, the upper end of the back support 1 is provided with a first joint 12 hinged to the first rotating part 31, and the lower end of the back support 1 is provided with a second joint 11 hinged to the second rotating part 41, the first joint 12 and the second joint 11 are both provided with a rotating shaft 7, the front end of the first rotating arm 32 and the front end of the second rotating arm 42 are both hinged to the corresponding position of the backrest assembly 2, so that the track change guide assembly forms a rotation support for the left and right sides of the backrest assembly 2; this symmetrical structure forms a four-bar structure at both ends of the left and right ends of the backrest assembly 2, so that the left and right ends of the backrest assembly 2 can move up and down at the same time.

[0058] Furthermore, in order to enhance the forward movement effect of the lower end of the backrest assembly 2 and amplify the back-chasing effect of the backrest assembly 2, the length of the first rotating arm 32 is smaller than the length of the second rotating arm 42; the longer second rotating arm 42 has a larger rotation radius, which can increase the forward movement degree of the lower end of the backrest assembly 2, thereby making the back-chasing effect of the backrest assembly 2 more significant.

[0059] Furthermore, in order to make the backrest assembly 2 move downward more smoothly, and to ensure that the backrest assembly 2 can automatically reset upward when the external force is removed, an elastic member that can reset the four-bar structure after deformation is provided between the chair back assembly and the track change guide assembly, and the elastic member is caused to deform when the backrest assembly 2 is triggered and moves downward under the action of the downward external force; when the external force is removed, the track change guide assembly can rotate upward relative to the back support 1 under the action of the elastic member to reset the backrest assembly 2 upward; the elastic member can provide a reset elastic force for the deformation of the four-bar structure, so that the backrest assembly 2 can automatically reset upward to a higher position; specifically, the four-bar structure formed between the track change guide assembly and the chair back assembly has four hinge ends, namely a first hinge point a, a second hinge point b, a third hinge point c, and a fourth hinge point d, and the elastic member is arranged at at least one hinge point The torsion spring 5 at the end position; the number of the torsion spring 5 can be increased or decreased according to the use requirements. Under the premise of sufficient elastic force, the torsion spring 5 in this embodiment is only arranged between the second joint 11 and the second rotating part 41, wherein the torsion spring 5 is a double-arm torsion spring, the back support 1 is provided with a torsion spring slot 13 with a front end opening, the second rotating part 41 is provided with a socket 44 facing the torsion spring slot 13, and the lower end of the double-arm torsion spring is provided with a U-shaped connecting part, the U-shaped connecting part is stuck in the torsion spring slot 13, and the two elastic arms at the upper end of the double-arm torsion spring are inserted into the socket 44, thereby realizing the up and down elastic rotation of the second rotating part 41. When the second rotating part 41 rotates up and down elastically, the torsion spring 5 can provide elastic force for the reset of the four-bar structure. At the same time, the torsion spring 5 occupies a small space, which is convenient for hiding in the hinged end formed by the track change guide assembly and the chair back assembly, and will not affect the appearance of the entire chair back assembly.

[0060] Furthermore, the chair back assembly and the track change guide assembly form a four-bar structure. In order to ensure that the backrest assembly 2 can move up and down freely, the deformation of the four-bar structure should be kept within a reasonable limit to avoid component collision or connecting rod jamming due to excessive deformation. Therefore, a protruding rotation limit tooth 43 is provided on the outer wall of the second rotating part 41, and the rotation limit tooth 43 can rotate synchronously with the second rotating part 41; the front end of the back support 1 is provided with a limiting surface s facing the rotation limit tooth 43; the limiting surface s is formed by a partial area of ​​the front end surface of the back support 1 being recessed inwardly, and when the backrest assembly 2 moves downward into place, the rotation limit tooth 43 abuts against the limiting surface s; when the backrest assembly 2 is reset upward, the rotation limit tooth 43 is separated from the limiting surface s; the design of the rotation limit tooth 43 and the limiting surface s can avoid excessive deformation of the four-bar structure, so that the backrest assembly 2 remains locked in position after rotating downward into place, so that the backrest assembly 2 can still provide stable support for the back after moving downward.

[0061] like Figure 4-11cAs shown, the chair back track changing mechanism also includes a locking component 6 arranged between the rotation limiting tooth 43 and the limiting surface s, a front end opening accommodating groove 14 is provided on the back support 1, and the accommodating groove 14 includes a mounting groove 142 opened in sequence from front to rear and a slide groove 141 recessed inwardly; the slide groove 141 is connected to the recessed area of ​​the limiting surface s; the locking component 6 includes a locking slider 63; the locking slider 63 includes a limiting end surface 633 facing the rotation limiting tooth 43, and the locking slider 63 slides in the slide groove 141; a fixing seat 62 is provided at the opening position of the slide groove 141, and the fixing seat 62 is in the mounting groove 142, and the fixing seat 62 restricts the locking slider 63 in the slide groove to prevent the locking slider 63 from escaping from the slide groove 141; when the backrest component 2 moves upward to the initial position, an empty area e is formed between the rotation limiting tooth 43 and the limiting surface s, and the locking slider 63 can fill or give up the empty area e by sliding itself, so that the rotation limiting The locking slider 63 is engaged with the locking teeth 43 to be limited or leave a rotation space, so that the locking slider 63 can lock or unlock the downward movement of the backrest component 2; the locking component 6 allows the backrest component 2 to be moved downward or locked downward according to actual needs, thereby expanding the application range of the chair back; that is, when the user needs to lock the backrest component 2 when the backrest component 2 is in a higher position so that it no longer moves downward, the locking slider 63 can be pushed in and fill the empty area e, so that the limiting end face 633 is engaged with the rotation limiting teeth 43. If the backrest component 2 does not need to be locked, there is no need to slide the locking slider 63 into the empty area e; this design allows the user to adjust the position of the locking slider 63 according to their own needs, so that the rotation limiting teeth 43 can selectively abut against the limiting end face 633. This design allows the backrest component 2 to have two supporting states of locking and downward movement in the reset state, thereby expanding the application range of the chair back.

[0062] Furthermore, the locking assembly 6 also includes a control wrench 61, which is an integrally formed open mold part. The control wrench 61 includes a handle 613 and a control part 614. The junction of the control part 614 and the handle 613 forms a rotating member 612 rotatably connected to the back bracket. The rotating member 612 is annular, and a rotating support seat 15 connected to the rotating member 612 is provided in the mounting groove 142. The rotating member 612 is connected to the rotating support seat 15 by screws, and the other end of the control part 614 is connected to a plug column 611; a waist-shaped groove 631 is provided on the locking slider 63, and the plug column 611 is slidably connected in the waist-shaped groove 631; the handle 613 is rotated to drive the locking slider 63 to slide to reach the corresponding position; the control wrench 61 is easy to be turned by external force, so that the user can control the locking or unlocking state of the backrest assembly 2; the control wrench 61 is easy to be turned by external force, so that the user can control the backrest assembly 2 to switch between the locked state and the unlocked state.

[0063] Furthermore, a guide groove 622 extending along the sliding direction of the locking slider 63 is provided on the end surface of the fixed seat 62 facing the locking slider 63, and a guide rail 632 is correspondingly provided on the end surface of the locking slider 63 facing the fixed seat 62, that is, the limiting end surface 633, and the guide rail 632 is slidably connected in the guide groove 622; the guide rail 632 cooperates with the guide groove 622 to play a sliding guiding role for the locking slider 63, so that the locking slider 63 fills or makes way for the empty area e.

[0064] Furthermore, an arc groove 621 corresponding to the rotation trajectory of the control part 614 is provided on the fixed seat 62, and the arc groove 621 includes a starting end 621a and an ending end 621b. The plug post 611 passes through the arc groove 621 and is inserted into the waist-shaped groove 631, and switches between the starting end 621a and the ending end 621b under the linkage of the rotating member 612 to drive the locking slider 63 to fill or give up the empty area e; when the arc groove 621 avoids the rotation trajectory of the control part 614, the starting end 621a and the ending end 621b can limit the swing range of the control part 614, so that the locking slider 63 slides within a reasonable range, thereby preventing the guide rail 632 from slipping out of the guide groove 622 due to excessive sliding range.

[0065] Furthermore, the control part 614 is a rod-shaped member. According to the actual sliding range of the locking slider 63, the rotation angle range of the control part 614 is usually 20°-30°. Correspondingly, the angle range between the two connecting lines formed by the starting end 621a and the ending end 621b of the arc groove 621 and the rotation center point of the control part 614 is also 20°-30°.

[0066] like Figure 10a-10b As shown, a chair is provided, including a seat 8 and the seat back track changing mechanism, the lower end of the back support 1 is rotatably connected to the rear end of the seat 8, and the seat back assembly can lean back to a tilted state under the action of an external force and trigger the backrest assembly 2 at the same time, so that the backrest assembly 2 moves from a higher position to a lower position forward and downward; specifically, when the occupant's back leans back, the seat back assembly will lean back to a tilted state, and during the leaning back process, the back will move forward and downward, and the friction between the back and the backrest assembly 2 will also cause the backrest assembly 2 to move forward and downward, so that the backrest assembly can achieve adaptive tracking support for the back, effectively protecting the back and avoiding the phenomenon of the lower end of the back being suspended in the air.

[0067] Example 2: Fig.12As shown, the difference between this embodiment and embodiment 1 is that, in this embodiment, the lengths of the first rotating arm 31 and the second rotating arm 42 are the same. When the trapezoidal four-bar linkage structure is deformed and the backrest assembly 2 moves downward, it mainly relies on the front end of the first rotating arm 31 to pull the upper end of the backrest assembly 2 backward, and the front end of the second rotating arm 42 to pull the lower end of the backrest assembly 2 forward, so as to achieve the chasing effect of the backrest assembly 2. Therefore, the chasing effect of the backrest assembly 2 does not absolutely rely on the technical feature that the length of the first rotating arm 42 is greater than the length of the first rotating arm 31. When the lengths of the first rotating arm 31 and the second rotating arm 42 are the same, the backrest assembly 2 can also achieve the chasing effect in the above embodiment.

[0068] The above schematically describes the present invention and its implementation methods, which are not restrictive. The drawings show only one implementation method of the present invention, and the actual structure is not limited thereto. Therefore, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A chair back track changing mechanism, characterized in that: include: A chair back assembly, comprising a back support (1) and a backrest assembly (2) arranged in front of the back support (1); The track change guide assembly is arranged between the back support (1) and the backrest assembly (2), and comprises a first linkage member (3) and a second linkage member (4) which are arranged at an interval up and down, wherein the front and rear ends of the first linkage member (3) are directly hinged to the backrest assembly (2) and the back support (1), respectively, and the front and rear ends of the second linkage member (4) are directly hinged to the backrest assembly (2) and the back support (1), thereby forming a four-link structure between the back support (1), the backrest assembly (2), the first linkage member (3) and the second linkage member (4); In an initial state, the backrest assembly (2) is in a higher position; when the backrest assembly (2) is triggered by a downward external force, it moves downward under the guidance of the track change guide assembly to switch to a lower position.

2. A seat back track changing mechanism according to claim 1, characterized in that: In the initial state, the first linkage member (3) extends forward or downward and is hinged to the upper end of the backrest assembly (2), and the second linkage member (4) extends forward and upward and is hinged to the lower end of the backrest assembly (2), thereby forming a trapezoidal four-bar structure with a narrow front and a wide rear between the track change guide assembly and the seat back assembly; When the backrest assembly (2) is triggered by a downward external force, the trapezoidal four-link structure deforms and drives the backrest assembly (2) to move downward, at which time the first linkage member (3) rotates downward and drives the upper end of the backrest assembly (2) to lean back, and the second linkage member (4) rotates downward and drives the lower end of the backrest assembly (2) to move forward.

3. The seat back track changing mechanism according to claim 1, characterized in that: The first linkage member (3) comprises a first rotating portion (31) hingedly connected to the back support (1), and a left-right symmetrical first rotating arm (32) is connected to the first rotating portion (31). The second linkage member (4) comprises a second rotating portion (41) hingedly connected to the back support (1), and a left-right symmetrical second rotating arm (42) is connected to the second rotating portion (41). The front ends of the first rotating arm (32) and the second rotating arm (42) are both hingedly connected to corresponding positions of the backrest assembly (2), so that the track change guide assembly forms a rotation support for both left and right sides of the backrest assembly (2).

4. A chair back track changing mechanism according to claim 3, characterized in that: The length of the first rotating arm (32) is smaller than the length of the second rotating arm (42).

5. The seat back track changing mechanism according to claim 1, characterized in that: An elastic member is provided between the chair back assembly and the track change guide assembly, which can cause the four-link structure to return to its original position after deformation. When the backrest assembly (2) is triggered and moves downward under the action of a downward external force, the elastic member is deformed. When the external force is removed, the track change guide assembly can be rotated upward relative to the back support (1) under the action of the elastic member, so that the backrest assembly (2) is returned to its original position upward.

6. A chair back track changing mechanism according to claim 5, characterized in that: The four-link structure formed between the track change guide assembly and the seat back assembly has four hinged ends, and the elastic member is a torsion spring (5) arranged at the position of at least one hinged end.

7. The seat back track changing mechanism according to claim 5, characterized in that: A protruding rotation limiting tooth (43) is provided on the outer wall of the second rotation part (41), and the rotation limiting tooth (43) can rotate synchronously with the second rotation part (41); a limiting surface (s) facing the rotation limiting tooth (43) is provided at the front end of the back support (1); when the backrest component (2) moves downward into position, the rotation limiting tooth (43) abuts against the limiting surface (s); when the backrest component (2) is reset upward, the rotation limiting tooth (43) separates from the limiting surface (s).

8. The seat back track changing mechanism according to claim 7, characterized in that: The invention also comprises a locking assembly (6) arranged between the rotation limiting tooth (43) and the limiting surface (s), wherein the locking assembly (6) comprises a locking slider (63); when the backrest assembly (2) moves upward to an initial position, an empty area (e) is formed between the rotation limiting tooth (43) and the limiting surface (s), and the locking slider (63) can fill or leave the empty area (e) by sliding itself, so that the rotation limiting tooth (43) and the locking slider (63) abut against each other to be limited or leave a rotation space, thereby enabling the locking slider (63) to lock or unlock the downward movement of the backrest assembly (2).

9. The seat back track changing mechanism according to claim 8, characterized in that: The locking assembly (6) further comprises a control wrench (61), the control wrench (61) comprising a handle (613) and a control portion (614); the interface between the control portion (614) and the handle (613) forms a rotating member (612) rotatably connected to the back support; an insertion column (611) is provided at one end of the control portion (614) away from the rotating member (612); a waist-shaped groove (631) is provided on the locking slide block (63), and the insertion column (611) is slidably connected in the waist-shaped groove (631); the handle (613) is turned to rotate, thereby driving the locking slide block (63) to slide, so as to reach a corresponding position.

10. The seat back track changing mechanism according to claim 8, characterized in that: The back support (1) is provided with a slide groove (141) which is recessed inwardly, and the locking slider (63) slides in the slide groove (141). A fixing seat (62) is provided at the opening of the slide groove (141), and the fixing seat (62) restricts the locking slider (63) in the slide groove.

11. The seat back track changing mechanism according to claim 10, characterized in that: A guide groove (622) extending along the sliding direction of the locking slider (63) is provided on the end surface of the fixed seat (62) facing the locking slider (63), and a guide rail (632) is correspondingly provided on the end surface of the locking slider (63) facing the fixed seat (62), and the guide rail (632) is slidably connected in the guide groove (622).

12. The seat back track changing mechanism according to claim 10, characterized in that: The fixed seat (62) is provided with an arc-shaped groove (621) corresponding to the rotation trajectory of the control part (614), and the arc-shaped groove (621) includes a starting end (621a) and an ending end (621b). The plug post (611) passes through the arc-shaped groove (621) and is inserted into the waist-shaped groove (631), and switches between the starting end (621a) and the ending end (621b) under the linkage of the rotating member (612), so as to drive the locking slider (63) to fill or make room for the empty area (e).

13. A seat, characterized in that: It comprises a seat (8) and a seat back track changing mechanism as claimed in any one of claims 1 to 12, wherein the lower end of the back support (1) is rotatably connected to the rear end of the seat (8), and the backrest assembly (2) drives the back support (1) to rotate backward under the action of a backward external force, so that the backrest assembly (2) moves from a higher position to a lower position forward and downward.

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