Chair frame with coupled backrest and seat

Abstract

Chair frame with coupled backrest and seat, characterized in that it comprises: a seat frame (1) whose rear end is hinged to the connecting seat (2), a backrest frame (3) which is connected to the aforementioned connecting seat (2), a return mechanism (4) which is mounted between the said seat frame (1) and the said connecting seat (2) for returning the said backrest frame (3), a sliding base plate for the backrest (5), which is mounted vertically slidable on the aforementioned backrest frame (3), a first sliding hinge mechanism (6) which is mounted between the said connecting seat (2) and the said sliding base plate for the backrest (5), so that leaning forward and backward of the said backrest frame (3) causes the said sliding base plate for the backrest (5) to move vertically, a seat sliding base plate (7) which is mounted on the aforementioned seat frame (1) so as to be slid forwards and backwards, a second sliding hinge mechanism (8) which is mounted between the said seat gliding base plate (7) and the said connecting seat (2) so that leaning forward and backward of the said backrest frame (3) causes the said seat gliding base plate (7) to move forward and backward.

Description

Technical field

[0001] The present utility model relates to the field of furniture technology, more precisely a chair frame with a coupled backrest and seat. Technical background

[0002] Chairs, especially office and leisure chairs, have become indispensable pieces of furniture in modern life and work. Users' demands for seating comfort are constantly increasing, with reclining chairs being very popular due to their ability to allow for a relaxed resting position. However, conventional reclining chairs typically achieve their tilting mechanism via a fixed pivot point. This simple rotational movement has a significant drawback: when a user's back reclines with the chair's backrest, their hip position remains relatively fixed or does not adjust accordingly. This results in noticeable relative movement between the user's back and the backrest padding. This uncomfortable sensation is often described by users as "back rubbing" or "clothing abrasion."This not only significantly impairs comfort but can also lead to discomfort and fatigue with prolonged use due to persistent friction and uneven pressure distribution. The reason lies in the fact that the traditional reclining mechanism does not allow for coordinated movement between the backrest and seat cushion to precisely match the natural posture of people when reclining, in which the hips and back move synchronously.

[0003] To address this problem, some solutions using prior art coupling mechanisms have been proposed to improve the reclining experience. For example, Chinese utility model application CN112190057A discloses a device to prevent back chafing. Its core innovation lies in the fact that back cushions can move relative to the backrest frame via rails. When a backrest reclines, a rotating linkage drives a back cushion downwards to actively conform to the user's back and reduce relative movement. However, this solution primarily focuses on back support and does not adequately consider or design coordinated movement of seat cushions. It cannot systematically solve the problem of coordinated movement between the hips and back while reclining.

[0004] For example, the Chinese utility model under disclosure number CN214258640U discloses a coupling mechanism for the backrest and seat. Using a drive rod and a four-joint mechanism, it synchronously raises the seat cushion and moves it forward when the backrest is reclined, thus achieving "zero displacement" and preventing back chafing. However, the path of movement for the upward lifting and forward movement of the seat cushion in this solution can alter the user's seating angle, so the effect of the coupled adjustment still needs optimization.

[0005] In summary, existing coupling solutions either exhibit insufficient adaptation between their movement paths and ergonomics, or they fail to fully account for the coordinated movement of the seat cushion and backrest. Therefore, there is an urgent need in this area for a novel seating structure that can more precisely and naturally simulate the human reclining posture and improve the coupling effect between the backrest and seat cushion to completely eliminate the sensation of "back rubbing". Content of the utility model

[0006] The purpose of the present utility model is to provide chair frames with coupled backrest and seat to solve prior art technical problems where uncoordinated coupling of seat cushion and backrest when leaning back leads to an inaccurate simulation of the natural posture of the human body, causing complaints such as "back rubbing sensation" or "abrasion of clothing" between the user's back and the backrest.

[0007] To achieve the aforementioned objective, the present utility model proposes a chair frame with a coupled backrest and seat, comprising the following: a seat frame whose rear end is hinged to the connecting seat, a backrest frame connected to the aforementioned connecting seat, a return mechanism which is mounted between the aforementioned seat frame and the aforementioned connecting seat for returning the backrest frame, a sliding base plate for the backrest, which is mounted vertically slidable on the aforementioned backrest frame, a first sliding hinge mechanism, which is mounted between the said connecting seat and the said sliding base plate for the backrest, so that leaning forward and backward of the said backrest frame causes the said sliding base plate for the backrest to move vertically, a seat sliding base plate which is mounted on the aforementioned seat frame so that it can be moved forwards and backwards, a second sliding hinge mechanism, which is mounted between the said seat gliding base plate and the said connecting seat, so that leaning forward and backward of the backrest frame causes the said seat gliding base plate to move forward and backward.

[0008] Preferably, the said seat frame comprises a base frame and a top frame, wherein the said top frame is mounted on the said base frame, and the said connecting seat is provided with a slide rail into which a wave rod is inserted, wherein the said wave rod is connected to the said top frame and can move within the said slide rail, and the said connecting seat is hinged to the said base frame.

[0009] Preferably, the first sliding hinge mechanism comprises a left-hand hinge group, wherein the left-hand hinge group comprises a first hinge plate, a second hinge plate, and a third hinge plate, wherein one end of the first hinge plate is hinged to the seat frame and another end is hinged at the point between the two ends of the second hinge plate, and the two ends of the second hinge plate are each hinged to the connecting seat and to one end of the third hinge plate, and another end of the third hinge plate is hinged to the sliding base plate for the backrest.

[0010] Preferably, the said left hinge group further comprises a first attachment part and a second attachment part, wherein the said first attachment part is mounted on the said seat frame and one end of the said first hinge plate is hinged to the said first attachment part, and the said second attachment part is installed on the said sliding base plate for the backrest and the end of the said third hinge plate facing away from the said second hinge plate is hinged to the said second attachment part.

[0011] Preferably, the first sliding hinge mechanism mentioned above further comprises a right-hand hinge group, wherein the right-hand hinge group has the same structure as the left-hand hinge group mentioned above and is arranged accordingly on the left and right sides between the connecting seat mentioned above and the sliding base plate for the backrest.

[0012] Preferably, the first sliding hinge mechanism further comprises a first connecting bracket, and the first connecting bracket is mounted on the connecting seat, wherein one end of the second hinge plate in the left hinge group is hinged to one end of the first connecting bracket and one end of the second hinge plate in the right hinge group is hinged to the other end of the first connecting bracket.

[0013] Preferably, the second sliding hinge mechanism comprises a left hinge plate, wherein the two ends of the left hinge plate are each hinged to the connecting seat and the seat sliding base plate.

[0014] Preferably, the second sliding hinge mechanism further comprises a right hinge plate, wherein the left hinge plate and the right hinge plate are arranged accordingly on the left and right sides between the connecting seat and the seat sliding base plate, and wherein the two ends of the right hinge plate are hinged to the connecting seat and the seat sliding base plate.

[0015] Preferably, the second sliding hinge mechanism further comprises a second connecting bracket, and the second connecting bracket is mounted on the seat sliding base plate, and the end of the left hinge plate facing the seat sliding base plate and the end of the right hinge plate facing the seat sliding base plate are hinged to the second connecting bracket.

[0016] Preferably, the return mechanism comprises a portal frame, a return spring and a guide rod, wherein the guide rod is installed on the seat frame and its longitudinal direction is the same as the front and rear direction of the seat frame, and wherein the portal frame is placed on the guide rod and is displaceable along the longitudinal direction of the guide rod, and wherein the return spring is placed on the guide rod and rests against the end of the guide rod and the portal frame, and wherein the portal frame is connected to the connecting seat.

[0017] Preferably, the said return mechanism further comprises an assembly for elasticity adjustment, wherein the said assembly for elasticity adjustment serves to adjust the spring force of the said return spring, with which the said portal frame is retracted into its initial position.

[0018] Preferably, the aforementioned assembly for elasticity adjustment comprises an adjusting rod and an adjusting gear, wherein one end of the aforementioned adjusting rod is provided with a toothed section, and wherein the toothed section engages in the aforementioned adjusting gear, and wherein the aforementioned adjusting gear is connected to the aforementioned guide rod.

[0019] Preferably, the connecting seat comprises a hinged seat and a connecting seat, wherein the hinged seat is hinged to the seat frame, wherein the connecting seat is mounted on the hinged seat and the lower end of the backrest frame is connected to the connecting seat.

[0020] Preferably, a first stop sliding element is installed on the said backrest frame and the said sliding base plate for the backrest is equipped with a vertical sliding rail, wherein the said first stop sliding element is inserted slidably into the said vertical sliding rail and the end of the said first stop sliding element rests on the side of the said sliding base plate for the backrest facing away from the said backrest frame, so that the said sliding base plate for the backrest is restricted from detaching from the said backrest frame.

[0021] Preferably, a second stop sliding element is installed on the said seat frame and the said seat sliding base plate is equipped with a sliding rail extending forwards and backwards, wherein the said second stop sliding element is inserted slidably into the said sliding rail forwards and backwards and the end of the said second stop sliding element rests against the upper side of the said seat sliding base plate, thus preventing the said seat sliding base plate from detaching from the said seat frame.

[0022] Preferably, the chair frame further comprises armrests, wherein said armrests are mounted on both sides of said seat glide base plate, or the chair frame further comprises a seat frame and armrests, wherein said seat frame is mounted on said seat glide base plate and both sides of said seat frame are provided with said armrests.

[0023] Preferably, the chair frame further comprises a gear adjustment mechanism between the said base and the said upper frame, wherein the said gear adjustment mechanism serves to lock the said backrest frame in the reclined position and to unlock the said backrest frame from this position, as well as to adjust the adjustment range of the reclining position of the said backrest frame.

[0024] Preferably, the gear-setting mechanism comprises a mounting seat, a step slider, a stop block, a locking cable and a gear-setting cable, wherein the mounting seat is installed on the base frame and the step slider is slidably installed on the mounting seat, and wherein the stop block is installed on the upper frame and corresponds to the step slider, and wherein both the locking cable and the gear-setting cable are connected to the step slider;By pulling the aforementioned locking cable or the aforementioned gear adjustment cable, the aforementioned step slider is driven to move along the aforementioned mounting seat so that various parts of the aforementioned step slider resist the aforementioned stop block, thereby achieving locking of the reclining position of the aforementioned backrest frame or realizing the adjustment range for the reclining position of the aforementioned backrest frame.

[0025] Preferably, the mounting seat has several stop grooves along the sliding direction of the step slide, and a downward-facing stop ball is mounted on the step slide; and when moved to different positions by the step slide, the ball of the stop ball engages in the different stop grooves.

[0026] This utility model relates to a chair frame with a coupled backrest and seat, which has at least the following advantageous effects: Due to the coupled construction of the connecting seat, the first sliding hinge mechanism and the second sliding hinge mechanism, reclining the backrest frame can synchronously cause the sliding base plate for the backrest to move downwards and the sliding base plate to move backwards, so that the relative distance and angle between the hip and back of a user change only very slightly or not at all, thereby effectively eliminating the “feeling of back rubbing” and increasing comfort when reclining backwards from the chair. Explanations of characters

[0027] To illustrate the technical solutions in the embodiments of the present utility model or in the prior art more clearly, the figures used in the embodiments or in the prior art are briefly presented. It is obvious that the figures described below represent only some embodiments of the present utility model. Engineers in this field can derive other figures from the structures shown in such figures without any creative effort. Fig. 1 The three-dimensional schematic structural representation of the chair frame in an embodiment of the present utility model; Fig. 2 The lateral schematic structural representation of the chair frame in an embodiment of the present utility model; Fig. 3 The lateral schematic structural representation of the chair frame in another state in an embodiment of the present utility model; Fig. 4 The three-dimensional schematic structural representation of the chair frame in another state in an embodiment of the present utility model; Fig. 5 The schematic structural representation of the reset mechanism in an embodiment of the present utility model; Fig. 6 The schematic structural representation of the seat frame in an embodiment of the present utility model; Fig. 7 The schematic structural representation of the connecting seat in an embodiment of the present utility model; Fig. 8 The schematic assembly structure representation of the seat frame, the connecting seat, the backrest frame, the sliding base plate for the backrest and the first sliding hinge mechanism in an embodiment of the present utility model; Fig. 9 The schematic assembly structure representation of the connecting seat, the backrest frame, the sliding base plate for the backrest and the first sliding hinge mechanism in an embodiment of the present utility model; Fig. 10 The schematic assembly representation of the seat frame, the connecting seat, the seat sliding base plate and the second sliding hinge mechanism in an embodiment of the present utility model; Fig. 11 The schematic structural representation of the Fig. 10. Structure shown from a different perspective; Fig. 12 The schematic structural representation of the adjusting rod in an embodiment of the present utility model; Fig. 13 The schematic assembly representation of the seat frame, the seat gliding base plate, the armrests and the seat frame in an embodiment of the present utility model; Fig. 14 The schematic assembly representation of the seat frame, the connecting seat and the gear adjustment mechanism in an embodiment of the present utility model; Fig. 15 The schematic structural exploded view of the upper frame and the stop block with regard to the Fig. 14 shown structure; Fig. 16 The schematic assembly representation of the mounting seat and the step slider in an embodiment of the present utility model.

[0028] In figures: 1- Seat frame; 11- Base frame; 12- Upper frame; 13- Shaft rod; 14- Second stop slide; 2- Connecting seat; 21- Slide rail; 22- Hinge seat; 23- Connecting seat; 3- Backrest frame; 31- First stop slide; 4- Return mechanism; 41- Portal frame; 42- Return spring; 43- Guide rod; 44- Elasticity adjustment assembly; 441- Adjusting rod; 442- Adjusting gear; 443- Tooth section; 5- Backrest sliding base plate; 51- Vertical slide rail; 6- First sliding hinge mechanism; 61- Left hinge group; 611- First hinge plate; 612- Second hinge plate; 613- Third hinge plate; 614- First attachment; 615- Second attachment; 62- Right hinge group; 63-First mounting bracket; 7-Seat sliding base plate; 71-Forward and backward sliding rail; 8-Second sliding hinge mechanism; 81-Left hinge plate; 82-Right hinge plate; 83-Second mounting bracket; 9-Armrest; 10-Seat frame; 110-Gear adjustment mechanism;111. Mounting seat; 112. Step slide; 113. Stop block; 114. Locking cable; 115. Gear adjustment cable; 116. Stop groove;

[0029] The achievement of objectives, functional characteristics and advantages of the present utility model are further explained in connection with the embodiments with reference to the attached figures. Detailed description of embodiments

[0030] The technical solutions of the embodiments of the present utility model are now clearly and completely presented with reference to the accompanying figures. It is obvious that the described embodiments represent only a portion of the embodiments and not all embodiments of the present utility model. Engineers in this field can, based on the embodiments of the present utility model, obtain other embodiments without creative effort that are also covered by the scope of protection of the present utility model.

[0031] It should be noted that if directional indicators (such as up, down, left, right, front, back, etc.) are present in the embodiments of this utility model, these directional indicators serve solely to explain the relative positions and movements of respective components in a specific orientation (as shown in the figures). Should this specific orientation change, the directional indicators will change accordingly.

[0032] Furthermore, if descriptions such as "first," "second," etc., are present in the embodiments of this utility model, such descriptions serve solely to describe the purpose and are not to be understood as indicating or suggesting a relative significance, nor as an implicit indication of the number of specified technical features. Consequently, features designated as "first" or "second" may explicitly or implicitly include at least one such feature. Moreover, technical solutions from different embodiments may be combined, provided such combinations are feasible for engineers in this field. If a combination of technical solutions proves to be contradictory or impracticable, such combination shall be deemed non-existent and shall not fall within the scope of protection of this utility model.

[0033] See Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. 5. A chair frame with a coupled backrest and seat comprises a seat frame 1, a connecting seat 2, a backrest frame 3, a return mechanism 4, a sliding base plate for the backrest 5, a first sliding hinge mechanism 6, a seat sliding base plate 7, and a second sliding hinge mechanism 8. The seat frame 1 serves as the basic support structure for the entire chair frame and supports components such as the seat and backrest, etc. When the user is seated in the chair, the end of the seat frame 1 facing the user's leg forms the front end, while the end facing the user's back forms the rear end. The connecting seat 2 is hinged to the rear end of the seat frame 1.Specifically, holes can be drilled at corresponding positions on seat frame 1 and connecting seat 2. A hinge pivot is then inserted into the holes of these two components to create a hinge connection between seat frame 1 and connecting seat 2. After the hinge connection, connecting seat 2 can rotate relative to seat frame 1 about its hinge point. The backrest frame 3 forms the basic support structure for the chair's backrest. Its lower end is connected to connecting seat 2 so that the backrest frame 3, together with connecting seat 2, can tilt forward and backward about its hinge point from both connecting seat 2 and seat frame 1. The return mechanism 4 is installed between seat frame 1 and connecting seat 2 to return the backrest frame 3 to its original position. Specifically, the return mechanism 4 can be mounted on seat frame 1 and coupled to connecting seat 2.When the user leans back and exerts force on the backrest frame 3, the return mechanism 4 is compressed. Upon removal of the external force, the return mechanism 4 releases its elastic potential energy and propels the connecting seat 2 and the backrest frame 3 to their vertical starting positions. The sliding base plate for the backrest 5 is mounted vertically displaceable on the front of the backrest frame. In finished products, back cushions, backrest foam, and other support structures that come into direct contact with the user's back are mounted on the sliding base plate for the backrest 5 and can move vertically with it. The first sliding hinge mechanism 6 is mounted between the connecting seat 2 and the sliding base plate for the backrest 5.When the backrest frame 3 tilts forward and backward, the rotation of the connecting seat 2 is converted via the first sliding hinge mechanism 6 into a pushing or pulling force on the sliding base plate for the backrest 5, causing it to slide up and down along the backrest frame 3. The seat sliding base plate 7 is mounted on the seat frame 1 so that it can slide forward and backward. In finished products, seat cushions, chair upholstery, and other support structures that come into direct contact with the user's hips are mounted on the seat sliding base plate 7 and can slide forward or backward with it. The second sliding hinge mechanism 8 is mounted between the seat sliding base plate 7 and the connecting seat 2.When the backrest frame 3 leans forward and backward, the rotation of the connecting seat 2 is converted via the second sliding hinge mechanism 8 into a pushing or pulling force on the seat sliding base plate 7, so that it moves forward or backward along the seat frame 1.

[0034] Fig. 1 and Fig. Figures 2 are schematic representations of the chair frame in its normal state. When the user leans back, the backrest frame 3 drives the connecting seat 2 to rotate backward. During this process, the connecting seat 2 actuates the first sliding hinge mechanism 6, which causes the sliding base plate for the backrest 5 to move downward so that the backrest is always in contact with the user's back. Simultaneously, the connecting seat 2 synchronously actuates the second sliding hinge mechanism 8, which causes the seat sliding base plate 7 to move backward so that the seat cushion follows the user's hip movement. The return mechanism 4 stores energy during this process. Fig. 3 and Fig. Figure 4 shows schematic representations of the chair frame in the position where the user is leaning back.

[0035] When the user no longer reclines, the return mechanism 4 releases energy and propels the connecting seat 2 and the backrest frame 3 to their starting positions. During this process, the connecting seat 2 actuates the first sliding hinge mechanism 6, which causes the sliding base plate for the backrest 5 to move upwards and return to its original position. Simultaneously, the connecting seat 2 synchronously actuates the second sliding hinge mechanism 8, which causes the seat sliding base plate 7 to move forwards and return to its original position. This coupling mechanism ensures that the relative distance and angle between the user's hips and back change very little, effectively eliminating the sensation of back rubbing.

[0036] In some embodiments, the seat frame 1 comprises, with reference to the Fig. 6 a base frame 11 and a top frame 12. The top frame 12 is attached to the base frame 11 by screws, together forming a stable support frame. Referring to the Fig. 7. The connecting seat 2 is provided with an elongated slide rail 21. A shaft rod 13 passes through this slide rail 21, with both ends of the shaft rod 13 being attached and mounted to the upper frame 12. Therefore, the connecting seat 2 is hinged to the rear end of the base frame 11 via its lower hinge hole and slidably connected to the upper frame 12 by the coordinated action of the slide rail 21 and the shaft rod 13. This combined hinge and sliding connection ensures that the connecting seat 2 can perform the intended reclining rotation under force, enabling stable and reliable movement. Furthermore, it increases the stability of the connection structure between the connecting frame and the seat frame and provides better support for the connecting frame and the backrest frame 3.

[0037] In some embodiments, the first sliding hinge mechanism 6 comprises, with reference to the Fig. 8 and Fig. 9 a left hinge group 61, wherein the left hinge group 61 comprises a first hinge plate 611, a second hinge plate 612, and a third hinge plate 613. One end of the first hinge plate 611 is hinged to the seat frame 1 via a pin, while the other end of the first hinge plate 611 is hinged to the position between the two ends of the second hinge plate 612 via a pin. One end of the second hinge plate 612 is hinged to the connecting seat 2 via a pin, while its other end is hinged to one end of the third hinge plate 613 via a pin. The other end of the third hinge plate 613 is hinged to the sliding base plate for the backrest 5 via a pin.Thus, the first hinge plate 611, the second hinge plate 612 and the third hinge plate 613 together with the seat frame 1, the connecting seat 2 and the sliding base plate for the backrest 5 form a multi-joint mechanism that can precisely convert the rotation of the connecting seat 2 into the vertical linear movement of the sliding base plate for the backrest 5.

[0038] Referring to the Fig. Figure 8 further comprises the left hinge assembly 61, specifically a first attachment 614 and a second attachment 615. The first attachment 614 is mounted on the left side of the seat frame 1, with one end of the first hinge plate 611 hinged to the first attachment 614 to form the aforementioned hinge connection with the seat frame 1. The second attachment 615 is mounted on the left side of the sliding base plate for the backrest 5, and the end of the third hinge plate 613 facing away from the second hinge plate 612 is hinged to the second attachment 615 to form a hinge connection with the sliding base plate for the backrest 5. The design of the first attachment 614 and the second attachment 615 facilitates the connection of the left hinge assembly 61 to the seat frame 1 and the sliding base plate for the backrest 5.

[0039] In some embodiments, the first sliding hinge mechanism 6 comprises, with reference to the Fig. 8 and Fig. 9. Furthermore, a right hinge group 62. The right hinge group 62 has the same structure as the left hinge group 61 and is located symmetrically on the right side between the connecting seat 2 and the sliding base plate for the backrest 5; that is, the left hinge group 61 and the right hinge group 62 are arranged symmetrically on the left and right sides between the connecting seat 2 and the sliding base plate for the backrest 5. The arrangement of the left hinge group 61 and the right hinge group 62 ensures that the sliding base plate for the backrest 5 is subjected to a uniform force during movement, thus preventing jamming or misalignment.

[0040] See Fig. 9. To increase structural integrity and synchronization, a first connecting bracket 63 is mounted on the connecting seat 2. The rear end of the second hinge plate 612 in the left hinge group 61 is hinged to the left end of the first connecting bracket 63; similarly, the rear end of the second hinge plate 612 in the right hinge group 62 is hinged to the right end of the first connecting bracket 63. The arrangement of the first connecting bracket 63 can increase the synchronization of the movement of the left hinge group 61 and the right hinge group 62. This can not only increase structural stability but also improve the smoothness of the sliding base plate for the backrest 5 during movement.

[0041] In some embodiments, the second sliding hinge mechanism 8 comprises, with reference to the Fig. 10. A left hinge plate 81. One end of the left hinge plate 81 is hinged to the left side of the connecting seat 2 via a pin, while its other end is hinged to the left side of the seat slide base plate 7 via a pin. When the connecting seat 2 rotates backward, the seat slide base plate 7 is pulled by the left hinge plate 81, thus performing its backward movement. The coupling of the seat slide base plate 7 and the connecting seat 2 is achieved by a single-joint mechanism.

[0042] In some embodiments, the second sliding hinge mechanism 8 comprises, with reference to the Fig. 10 furthermore a right hinge plate 82. This right hinge plate 82 has the same structure as the left hinge plate 81 and is located symmetrically on the right side between the connecting seat 2 and the seat slide base plate 7. The symmetrical arrangement of the left hinge plate 81 and the right hinge base plate 82 on two sides ensures that the seat slide base plate 7 is subjected to a uniform force during movement, thus preventing jamming or misalignment.

[0043] Referring to Fig. A second connecting bracket 83 is fixedly mounted below the seat sliding base plate 7. The upper ends of both the left hinge plate 81 and the right hinge plate 82 are hinged to the second connecting bracket 83. This double-sided arrangement increases the stability and load-bearing capacity of the seat sliding base plate 7 as a drive mechanism. The second connecting bracket 83 ensures fully synchronous movement of the left and right hinge plates and increases the smoothness of the seat sliding base plate 7.

[0044] In some embodiments, the reset mechanism 4 comprises, with reference to the Fig. Figure 5 comprises a portal frame 41, a return spring 42, and a guide rod 43. The guide rod 43 lies within the seat frame 1, its longitudinal direction being the same as the front and rear directions of the seat frame 1. The portal frame 41 has a cross member and two side arms that form a portal-like structure. Holes are provided in the cross member of the portal frame 41 through which the portal frame 41 is placed onto the guide rod 43. The portal frame 41 can also slide along the longitudinal direction of the guide rod 43. The two side arms of the portal frame 41 are connected to the left and right sides of the connecting seat 2, respectively.

[0045] A return spring 42 is mounted on the guide rod 43, with both ends of the return spring 42 abutting the ends of the guide rod 43. The portal frame 41 lies between the two ends of the return spring 42, and the return spring 42 also rests against the cross member of the portal frame 41. When the connecting seat 2 rotates backward, it causes the portal frame 41 to move backward along the longitudinal direction of the guide rod 43, thus compressing the return spring 42. When the reclining force is released, the return spring 42 causes the portal frame 41 to move forward, driving the connecting seat 2 and the backrest frame 3 back to their initial positions.

[0046] In some embodiments, the reset mechanism 4 comprises, with reference to the Fig. 5 furthermore an elasticity adjustment assembly 44. This elasticity adjustment assembly 44 is used to adjust the preload of the return spring 42 and to change the force required to return the backrest frame 3 in order to adapt to the needs of users with different body weights.

[0047] Referring to the Fig. 5 The assembly for elasticity adjustment 44 specifically comprises an adjusting rod 441 and an adjusting gear 442. Referring to the Fig. In step 12, one end of the adjusting rod 441 is provided with a toothed section 443, and the adjusting rod 441 is rotatably mounted on the seat frame 1. The adjusting gear 442 engages in the toothed section 443 of the adjusting rod 441 and is connected to the guide rod 43. When the user rotates the adjusting rod 441, this drives the adjusting gear 442 to rotate. The guide rod 43 rotates with the adjusting gear 442. The rotation of the guide rod 43 causes the return spring 42 to rotate, which in turn changes the position of the portal frame 41 on the return spring 42 and alters the preload of the portal frame 41 on the return spring 42, thus enabling stepless adjustment of the spring force.

[0048] In some embodiments, the connecting seat 2 comprises, with reference to the Fig. 7 a hinged seat 22 and a connecting seat 23. The front end of the hinged seat 22 is hinged to the seat frame 1, and the connecting seat 23 is screwed to the hinged seat 22 and extends to the rear. The lower end of the backrest frame 3 is fixedly connected to the connecting seat 23. This split design facilitates machining and assembly. Connecting seats 23 with different specifications can be selected as needed to adapt to backrest frames 3 with different designs; it also facilitates the coupling between the backrest sliding base 5 and the seat sliding base 7.

[0049] In some embodiments, several first stop sliding parts 31 are referred to by reference to the Fig. 8 mounted on the backrest frame 3. Specifically, four first stop slides 31 can be mounted, arranged in a rectangular shape. The sliding base plate for the backrest 5 is provided with vertical slide rails 51, the number of which is identical to the number of first stop slides 31, and there is a one-to-one correspondence between them. The first stop slides 31 are workpieces with a T-shaped cross-section. Each first stop slide can be inserted slidably into the vertical slide rail 51, and the end of each first stop slide rests against the side facing away from the backrest frame 3 (i.e., the front side) of the sliding base plate for the backrest 5, so that the sliding base plate for the backrest 5 is "clamped" onto the backrest frame 3. This allows vertical movement of the sliding base plate for the backrest 5 and simultaneously effectively prevents it from detaching from the backrest frame 3.

[0050] In some embodiments, several second stop sliding parts 14 are referred to by reference to the Fig. 11 is mounted on the seat frame 1. Specifically, four second stop slides 14 can be mounted, arranged in a rectangular shape. The seat base plate 7 is provided with forward and backward slide rails 71, the number of which is identical to the number of second stop slides 14, and there is a one-to-one correspondence between them. The second stop slides 14 are workpieces with a T-shaped cross-section. Every second stop slide can be inserted slidably into the forward and backward slide rail 71, and the end of every second stop slide 14 rests against the top of the seat base plate 7, thus limiting the upward movement of the seat base plate 7 from the seat frame 1 and simultaneously ensuring rapid forward and backward movement of the seat base plate 7.

[0051] In some embodiments, the chair frame includes remote armrests 9, and the armrests 9 are mounted on both sides of the seat glide plate 7. When the seat glide plate 7 moves forward, the armrests 9 are driven to move synchronously. Consequently, the armrests 9 provide support for the user's arms in both sitting and reclining positions, thus increasing user comfort.

[0052] In some embodiments, the chair frame includes, with reference to the Fig. 13. The seat frame 10 and armrests 9 are also included. The seat frame 10 is attached to the seat glide base 7 and moves forward and backward synchronously with the seat glide base 7. At this time, the seat cushion or upholstery is attached to the seat frame 10. The armrests 9 are mounted on both sides of the seat frame 10, causing the armrests 9, the seat frame 10, and the seat glide base 7 to move synchronously. The armrests 9 provide support for the user's arms, thus increasing user comfort. The seat frame 10 facilitates the installation of the armrests 9, seat cushion, and upholstery.

[0053] In some embodiments, the chair frame includes, with reference to the Fig. 14. Furthermore, a gear adjustment mechanism 110 is located between the base frame 11 and the upper frame 12. This gear adjustment mechanism 110 serves to lock and unlock the backrest frame 3, as well as to adjust the adjustment range of the backrest position of the backrest frame 3. By adjusting this gear adjustment mechanism 110, the backrest frame 3 can not only be locked to prevent reclining, but it can also be unlocked, and the maximum tilt angle of the backrest frame 3 can be set. For example, four gears can be set: namely, locked gear, 10°, 20°, and 30°, which mean the following: the backrest frame 3 cannot recline, or can recline to a maximum of 10°, 20°, or 30°, respectively.Of course, the tilt angle for each gear can be flexibly adjusted; and gears can be set with different numbers, for example, the third gear, the fifth gear, and the sixth gear.

[0054] Referring to the Fig. The gear-setting mechanism 110 comprises, specifically, a mounting seat 111, a step slider 112, a stop block 113, a locking cable 114, and a gear-setting cable 115. The mounting seat 111 can be fixed to the base frame 11 with screws. The step slider 112 can be mounted on the mounting seat 111 so that it can slide along the left and right sides. The side of the step slider 112 facing the stop block 113 is designed with a stepped profile of varying heights, comprising a highest locking surface and several successive lower stop surfaces. The stop block 113 is mounted on the upper frame 12 and suspended above the step slider 112, and corresponds to the stepped profile of the step slider 112. Both the locking cable 114 and the gear-setting cable 115 are connected to the step slider 112.Pulling the locking cable 114 or the gear adjustment cable 115 causes the step slider 112 to move along the mounting seat 111 so that different parts of the step slider 112 resist the stop block 113, thereby either locking the reclining of the backrest frame 3 or adjusting the reclining range of the backrest frame 3. When the user pulls the locking cable 114 and the step slider 112 moves fully to the right on the mounting seat 111, the highest locking surface of the step slider 112 rests against the lower end of the stop block 113. This causes the stop block 113 and the upper frame 12 to rise relative to the lower frame 11 by a certain height, and subsequently, the lower frame 11 pulls the connecting seat 2, thus restricting the rearward rotation of the connecting seat 2 and locking the reclining function of the backrest frame 3.When the user pulls the gear adjustment cable 115, the step slider 112 on the mounting seat 111 moves to the left into various preset positions. When the step slider 112 is in different positions, its stop surfaces rest at different heights against the lower end of the stop block 113. This causes the stop block 113 and the upper frame 12 to rise by a slightly different height relative to the lower frame 11, so that it pulls the connecting seat 2 through the lower frame 11 and thereby limits the maximum rearward rotation angle of the connecting seat 2.

[0055] In some embodiments, the mounting seat 111 is referred to by reference to the Fig.The step slider 112 is provided with several stop grooves 116 along its sliding direction. A stop ball (not shown in the figure) is mounted on the underside of the step slider 112. This stop ball typically consists of a spring-loaded ball oriented downwards and facing one of the stop grooves 116 on the mounting seat 111. As the step slider 112 moves to different positions, the ball of the stop ball engages in a different stop groove 116. When the user pulls the gear-setting cable 115 or the locking cable 114 and the step slider 112 moves, the ball slides out of a stop groove 116 and slides on the flat surface of the mounting seat 111. As the step slider 112 moves to the next target position, the ball engages in the corresponding stop groove 116 with a distinct "click" under the action of an internal spring.This design provides the user with clear tactile feedback for gear selection. Simultaneously, the mechanical interlock effectively locks the step slider 112 in the current gear, ensuring precise and reliable gear selection and preventing unintentional gear changes during use caused by vibrations or other factors.

[0056] The above-mentioned presentation merely represents preferred embodiments of the present utility model and does not limit the scope of the claims of the utility model. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 112190057A

[0003] CN 214258640U

[0004]

Claims

[1] Chair frame with coupled backrest and seat, characterized by that it includes: a seat frame (1) whose rear end is hinged to the connecting seat (2), a backrest frame (3) which is connected to the aforementioned connecting seat (2), a return mechanism (4) which is mounted between the said seat frame (1) and the said connecting seat (2) for returning the said backrest frame (3), a sliding base plate for the backrest (5), which is mounted vertically slidable on the aforementioned backrest frame (3), a first sliding hinge mechanism (6) which is mounted between the said connecting seat (2) and the said sliding base plate for the backrest (5), so that leaning forward and backward of the said backrest frame (3) causes the said sliding base plate for the backrest (5) to move vertically, a seat sliding base plate (7) which is mounted on the aforementioned seat frame (1) so as to be slid forwards and backwards, a second sliding hinge mechanism (8) which is mounted between the said seat gliding base plate (7) and the said connecting seat (2) so that leaning forward and backward of the said backrest frame (3) causes the said seat gliding base plate (7) to move forward and backward. [2] Chair frame with coupled backrest and seat according to claim 1, characterized by , that the said seat frame (1) comprises a base frame (11) and a top frame (12), wherein the said top frame (12) is mounted on the said base frame (11), and that the said connecting seat (2) is provided with a slide rail (21), into the said slide rail (21) a shaft rod (13) is inserted, the said shaft rod (13) being connected to the said upper frame (12) and being able to move within the said slide rail (21), and that the said connecting seat (2) is hinged to the said base (11). [3] Chair frame with coupled backrest and seat according to claim 1, characterized by, that the said first sliding hinge mechanism (6) comprises a left hinge group (61), wherein the said left hinge group (61) comprises a first hinge plate (611), a second hinge plate (612) and a third hinge plate (613), and wherein one end of the said first hinge plate (611) is hinged to the said seat frame (1) and another end is hinged at the point between the two ends of the said second hinge plate (612), and wherein the two ends of the said second hinge plate (612) are each hinged to the connecting seat (2) and to one end of the said third hinge plate (613), and wherein another end of the said third hinge plate (613) is hinged to the said sliding base plate for the backrest (5). [4] Chair frame with coupled backrest and seat according to claim 3, characterized by , that the said left hinge group (61) further comprises a first attachment part (614) and a second attachment part (615), wherein the said first attachment part (614) is mounted on the said seat frame (1) and one end of the said first hinge plate (611) is hinged to the said first attachment part (614), and that the said second attachment part (615) is installed on the said sliding base plate for the backrest (5) and that the end of the said third hinge plate (613) facing away from the said second hinge plate (612) is hinged to the said second attachment part (615). [5] Chair frame with coupled backrest and seat according to claim 2 or 3, characterized by, that the said first sliding hinge mechanism (6) further comprises a right hinge group (62), wherein the said right hinge group (62) has the same structure as the said left hinge group (61) and is arranged accordingly on the left and right sides between the said connecting seat (2) and the said sliding base plate for the backrest (5). [6] Chair frame with coupled backrest and seat according to claim 5, characterized by, that the said first sliding hinge mechanism (6) further comprises a first connecting bracket (63), wherein the said first connecting bracket (63) is mounted on the said connecting seat (2), and wherein one end of the said second hinge plate (612) in the said left hinge group (61) is hinged to one end of the said first connecting bracket (63) and one end of the second hinge plate (612) in the said right hinge group (62) is hinged to the other end of the said first connecting bracket (63). [7] Chair frame with coupled backrest and seat according to claim 1, characterized by , that the said second sliding hinge mechanism (8) comprises a left hinge plate (81), wherein the two ends of the said left hinge plate (81) are each hinged to the said connecting seat (2) and to the said seat sliding base plate (7). [8] Chair frame with coupled backrest and seat according to claim 7, characterized by , that the said second sliding hinge mechanism (8) further comprises a right hinge plate (82), wherein the said left hinge plate (81) and the said right hinge plate (82) are arranged accordingly on the left and right sides between the said connecting seat (2) and the said seat sliding base plate (7), and wherein the two ends of the said right hinge plate (82) are hinged to the said connecting seat (2) and to the said seat sliding base plate (7), respectively. [9] Chair frame with coupled backrest and seat according to claim 8, characterized by, that the said second sliding hinge mechanism (8) further comprises a second connecting bracket (83), wherein the said second connecting bracket (83) is mounted on the said seat sliding base plate (7), and wherein the end of the said left hinge plate (81) facing the said seat sliding base plate (7) and the end of the said right hinge plate (82) facing the said seat sliding base plate (7) are hinged to the said second connecting bracket (83). [10] Chair frame with coupled backrest and seat according to claim 1, characterized by, that the said return mechanism (4) comprises a portal frame (41), a return spring (42) and a guide rod (43), wherein the said guide rod (43) is installed on the said seat frame (1) and its longitudinal direction is the same as the front and rear direction of the said seat frame (1), and wherein the said portal frame (41) is placed on the said guide rod (43) and is displaceable along the longitudinal direction of the said guide rod (43), and wherein the said return spring (42) is placed on the said guide rod (43) and bears against the end of the said guide rod (43) and against the said portal frame (41), and wherein the said portal frame (41) is connected to the said connecting seat (2). [11] Chair frame with coupled backrest and seat according to claim 10, characterized by, that the said return mechanism (4) further comprises an elasticity adjustment assembly (44), wherein the said elasticity adjustment assembly (44) serves to adjust the spring force of the said return spring (42) with which the said portal frame (41) is retracted into its initial position. [12] Chair frame with coupled backrest and seat according to claim 11, characterized by , that the said elasticity adjustment assembly (44) comprises an adjusting rod (441) and an adjusting gear (442), wherein one end of the said adjusting rod (441) is provided with a toothed section (443), and wherein the said toothed section (443) engages in the said adjusting gear (442), and wherein the said adjusting gear (442) is connected to the said guide rod (43). [13] Chair frame with coupled backrest and seat according to claim 1, characterized by, that the said connecting seat (2) comprises a hinged seat (22) and a connecting seat (23), wherein the said hinged seat (22) is hinged to the said seat frame (1), and wherein the said connecting seat (23) is mounted on the said hinged seat (22) and the lower end of the said backrest frame (3) is connected to the said connecting seat (23). [14] Chair frame with coupled backrest and seat according to claim 1, characterized by, that a first stop sliding part (31) is installed on the said backrest frame (3), wherein the said sliding base plate for the backrest (5) is equipped with a vertical sliding rail (51), and wherein the said first stop sliding part (31) is inserted slidably into the said vertical sliding rail (51) and the end of the said first stop sliding part (31) rests against the side of the said sliding base plate for the backrest (5) facing away from the said backrest frame (3), so that the said sliding base plate for the backrest (5) is restricted from detaching from the said backrest frame (3). [15] Chair frame with coupled backrest and seat according to claim 1, characterized by, that a second stop sliding part (14) is installed on the said seat frame (1), wherein the said seat sliding base plate (7) is equipped with a sliding rail (71) extending forwards and backwards, wherein the said second stop sliding part (14) is inserted slidingly into the said sliding rail (71) extending forwards and backwards, and the end of the said second stop sliding part (14) rests against the upper side of the said seat sliding base plate (7) in such a way as to restrict the said seat sliding base plate (7) from detaching from the said seat frame (1). [16] Chair frame with coupled backrest and seat according to claim 1, characterized by , that it further comprises armrests (9), wherein said armrests (9) are mounted on both sides of said seat gliding base plate (7), or that it further comprises a seat frame (10) and armrests (9), wherein the said seat frame (10) is mounted on the said seat sliding base plate (7) and the two sides of the said seat frame (10) are provided with the said armrests (9). [17] Chair frame with coupled backrest and seat according to claim 2, characterized by , that it further comprises a gear adjustment mechanism (110) between the said base frame (11) and the said upper frame (12); wherein the said gear adjustment mechanism (110) serves to lock the reclining position of the said backrest frame (3) and to unlock the said backrest frame (3) from this position, as well as to adjust the adjustment range of the reclining position of the said backrest frame (3). [18] Chair frame with coupled backrest and seat according to claim 17, characterized by, that the said gear-setting mechanism (110) comprises a mounting seat (111), a step slider (112), a stop block (113), a locking pull cable (114) and a gear-setting pull cable (115), wherein the said mounting seat (111) is installed on the said base frame (11) and the said step slider (112) is slidably installed on the said mounting seat (111), and wherein the said stop block (113) is installed on the said upper frame (12) and corresponds to the said step slider (112), and wherein both the said locking pull cable (114) and the said gear-setting pull cable (115) are connected to the said step slider (112);and that by pulling the said locking cable (114) or the said gear adjustment cable (115), the said step slider (112) is driven to move along the said mounting seat (111) so that various parts of the said step slider (112) resist the said stop block (113), thereby achieving locking of the reclining position of the said backrest frame (3) or achieving adjustment of the reclining position adjustment range of the said backrest frame (3). [19] Chair frame with coupled backrest and seat according to claim 18, characterized by, that the said mounting seat (111) has several stop grooves (116) along the sliding direction of the said step slide (112), wherein a downwardly directed stop ball is mounted on the said step slide (112); and that when shifted into different positions by the said step slide (112), the ball of the said stop ball engages in the said different stop grooves (116).

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