Headrest

Abstract

The invention discloses a headrest which comprises a base, a first connecting rod set, a transmission part, a second connecting rod set, a headrest frame and a headrest frame. The base is used for being connected with a chair back and connected with the transmission piece through the first connecting rod set, the transmission piece is connected with the back cushion frame through the second connecting rod set, and the back cushion frame is used for bearing the head and neck. The base, the first connecting rod group and the transmission piece form a first four-connecting-rod mechanism, the transmission piece, the second connecting rod group and the back cushion frame form a second four-connecting-rod mechanism, and the back cushion frame achieves multi-dimensional movement through the two mechanisms; the second connecting rod group comprises a locking connecting rod which is rotationally connected with a driving piece, an operating piece is slidably arranged on the back cushion frame, and the locking connecting rod and the back cushion frame are matched through a first arc-shaped surface and a second arc-shaped surface to lock relative rotation of the connecting rod and the back cushion frame; the first arc-shaped surface is slotted to form two side walls, the second arc-shaped surface is convexly provided with a transmission part, and the transmission part is located between the two side walls and always abuts against the two side walls for transmission; the operating piece slides to drive the driving piece to rotate, locking and unlocking of the two connecting rod mechanisms are achieved, operation is convenient, and transmission is not affected by rotation of the back cushion frame.

Description

[0001] This application is a divisional application of CN 202510254176.8. The original application was filed on March 5, 2025; the original application number was CN 202510254176.8; and the original invention was entitled "An Adjustment Device and a Headrest". Technical Field

[0002] This invention relates to the field of seating, and more particularly to a headrest. Background Technology

[0003] In modern life, the comfort and functionality of seats are receiving increasing attention. As an important component of seats, the headrest's adjustability directly affects the user's experience.

[0004] Traditional headrest adjustments have many shortcomings. Some headrests can only be adjusted in one direction, which cannot meet the diverse needs of the human head and neck in different postures, making it difficult to effectively relieve physical fatigue and not in line with ergonomic principles.

[0005] Some devices with multi-directional adjustment functions have complex structures and are inconvenient to operate. Users often need to spend a lot of time and effort to adjust them, and may still not achieve the desired support position, resulting in poor ease of use and applicability. The locking and unlocking of multi-dimensional adjustable headrests is particularly problematic. Multi-dimensional adjustable headrests often have complex linkage mechanisms, and the headrest frame often has the ability to rotate. After the headrest is adjusted, it adapts to the curve of the human head and neck. However, users usually adjust the headrest while seated. The control switch is most convenient to operate if it is located on the headrest frame. However, the actual locking mechanism must be set within the linkage mechanism to lock after the movement is completed. This necessitates a transmission path between the control switch and the locking mechanism. As mentioned above, since the headrest frame can rotate, the transmission between the control switch and the locking mechanism needs to be adapted to the rotation of the headrest. Currently, only expensive cable devices can achieve this, and the required cable length is relatively long.

[0006] Therefore, there is an urgent need for a controllable locking headrest that can solve the above problems at a lower cost. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a headrest comprising a base, a first linkage group, a transmission component, a second linkage group, a headrest frame, and a headrest backrest. The base connects to the chair back and is connected to the transmission component via the first linkage group. The transmission component connects to the headrest frame via the second linkage group. The headrest frame supports the head and neck. The base, the first linkage group, and the transmission component constitute a first four-bar linkage mechanism, while the transmission component, the second linkage group, and the headrest frame constitute a second four-bar linkage mechanism. The headrest frame achieves multi-dimensional movement through these two mechanisms. The second linkage group includes a locking linkage rotatably connected to a driving component. An operating component is slidably mounted on the headrest frame. The two components are adapted to the relative rotation of the locking linkage and the headrest frame via first and second arc-shaped surfaces. The first arc-shaped surface has slots forming two side walls, and the second arc-shaped surface has a protruding transmission component located between the two side walls and always abutting against the transmission. The sliding operation component can drive the driving component to rotate, realizing the locking and unlocking of the two linkage mechanisms. The operation is convenient, and the transmission is not affected by the rotation of the headrest frame, ensuring stable support and adjustment of the headrest.

[0008] The technical solution of this invention is implemented as follows: A headrest includes a base for connecting to a seat back, a first linkage group connected to the base, a transmission component connected to the other end of the first linkage group, a second linkage group connected to the other end of the transmission component, and a headrest frame connected to the other end of the second linkage group. The headrest frame is provided with a headrest frame for conforming to and supporting the head and neck of a human. The base, the first linkage group, and the transmission component constitute a first linkage mechanism, and the transmission component, the second linkage group, and the headrest frame constitute a second linkage mechanism. Both the first and second linkage mechanisms are four-bar linkage mechanisms. The headrest frame moves relative to the base through the first and second linkage mechanisms, and the movement of the headrest frame drives the headrest frame to move together. The second linkage group includes a locking linkage, a headrest frame rotatably connected to the locking linkage, a driving member rotatably provided on the locking linkage, an operating member slidably provided on the headrest frame, the operating member being connected to the driving member in a transmission manner, and the operating member being configured to control the rotation of the driving member relative to the locking linkage and simultaneously lock or unlock the movement of the first and second linkage mechanisms. The operating component has a first connecting part at its rear end and a second connecting part at its front end. The first connecting part has a first arc-shaped surface facing the second connecting part, and the second connecting part has a corresponding second arc-shaped surface. The first and second arc-shaped surfaces cooperate with each other to allow the driving component and the operating component to adapt to the relative rotation of the locking link and the headrest frame. A groove is made on the first arc-shaped surface of the first connecting part to form two sidewalls. A transmission part is protruding forward on the second arc-shaped surface of the second connecting part. The transmission part is located between the two sidewalls and is configured to abut against the sidewalls for transmission. When the operating component slides, the sidewalls can push the transmission part to move at any position of the transmission part, so that the sliding of the operating component can always be transmitted to the driving component.

[0009] In this headrest, the headrest frame moves together with the headrest bracket. The headrest bracket achieves multi-dimensional movement under the action of the first and second linkage mechanisms. Since both the first and second linkage mechanisms are four-bar linkages, the headrest bracket needs to be rotatably connected to the locking link in the second linkage group when forming the four-bar linkage. Furthermore, when the headrest supports the user's head and neck, both the first and second linkage mechanisms need to be locked together. Simultaneously, the user-controlled locking and unlocking mechanism is located on the headrest bracket for convenient operation. The actual locking and unlocking drive mechanism is rotatably located on the locking link to lock or unlock the two four-bar linkages. This means that when the control mechanism moves the drive mechanism, it must adapt to the rotational movement of the headrest bracket and the locking link. Even if the headrest bracket and the locking link rotate relative to each other, the control mechanism can still be linked with the drive mechanism. Therefore, the control mechanism is equipped with... The first connecting part has a first arc-shaped surface, and the driving member has a second connecting part with a second arc-shaped surface. The first arc-shaped surface and the second arc-shaped surface cooperate with each other to adapt to the relative rotation of the locking link and the headrest frame, keeping the first connecting part and the second connecting part always matched. At the same time, a slot is made in the first arc-shaped surface to form two side walls, and a forward-protruding transmission part is provided on the second arc-shaped surface, so that the transmission part is located between the two side walls. After the operating member and the driving member rotate with the rotation of the locking link and the headrest frame, the transmission part is still located between the two side walls, but the transmission part moves to other positions on the side walls. The transmission part and the side walls can always maintain contact and transmission. When the operating member slides, the side walls can drive the transmission part to move, thereby causing the driving member to rotate. Therefore, the transmission between the operating member and the driving member is not affected by the rotation of the headrest frame, and always plays the role of controlling the locking or unlocking of the headrest.

[0010] Preferably, the sidewalls are located beside the first arcuate surface and further forward relative to it; when the headrest frame and locking link rotate, the transmission unit rotates between the two sidewalls. As the headrest frame and locking link rotate, the transmission unit rotates accordingly between the sidewalls, but they always maintain contact and transmission, preventing the transmission unit from disengaging from the sidewalls and thus preventing the operating component from losing control of the driving component.

[0011] Preferably, the transmission part is spherical. This reduces the contact between the transmission part and the side wall, thus not affecting the smooth rotation of the headrest frame.

[0012] Preferably, the pillow frame has a receiving groove, and the operating component is slidably disposed in the receiving groove.

[0013] Preferably, the first linkage group includes a passive linkage, a locking linkage, and a drive member. The passive linkage and the locking linkage are rotatably mounted on the transmission member via the same rotating shaft. A first locking member and a second locking member are linked on the drive member. The passive linkage has a first locking part, and the first locking member is located beside the first locking part. The headrest frame has a second locking part, and the second locking member is located beside the second locking part. Both the first and second locking members move closer to or further away from their respective locking parts as the drive member rotates. When the first and second locking members simultaneously approach and lock into their respective locking parts, the movement of the first and second linkage mechanisms is simultaneously locked, and the relative position of the headrest frame and the base is locked. Through the above arrangement, the first locking member can simultaneously lock the passive linkage, the locking linkage, and the transmission member. At this point, only the second locking member needs to lock the locking linkage and the headrest frame to achieve overall locking, which is simple, fast, and compatible with the connection structure of the operating member and the drive member.

[0014] Preferably, the driving component is rotatably connected to the locking linkage at its middle section, and both ends of the driving component are respectively connected to the first locking component and the second locking component for transmission. When the driving component rotates, it simultaneously controls the movement of the first locking component and the second locking component. This simplifies the locking structure and locking operation.

[0015] Preferably, the driving component has a first waist-shaped groove and a second waist-shaped groove, the first locking component has a first transmission column, and the second locking component has a second transmission column. The first transmission column is inserted into the first waist-shaped groove, and the second transmission column is inserted into the second waist-shaped groove. The driving component and the locking component achieve transmission through the waist-shaped groove and the transmission column, which is simple in structure; moreover, even if the motion mechanism changes its own posture after movement, the transmission column can still remain in the waist-shaped groove.

[0016] Preferably, one end of the locking link is inserted with a rotating shaft, and the other end is inserted with a first rotating shaft. The locking link is rotatably connected to the pillow frame through the first rotating shaft. A first locking member is slidably disposed on the rotating shaft, and a second locking member is slidably disposed on the first rotating shaft. Under the action of the driving member, the first and second locking members slide on the rotating shaft to achieve locking and unlocking. In addition, a circumferential limiting structure needs to be provided between the first and second locking members and the locking link to maintain the synchronous rotation of the first and second locking members and the locking link. The circumferential limiting structure can be a convex-groove structure, etc.

[0017] Preferably, the first locking member, the second locking member, the first locking part, and the second locking part are all uniformly distributed with a plurality of meshing teeth in the circumferential direction. The first locking member selectively engages with the first locking part, and the second locking member selectively engages with the second locking part. The meshing and locking of the locking member and the locking part are achieved by the meshing teeth that are uniformly distributed in the circumferential direction on the same plane.

[0018] Preferably, the first linkage group includes a first movable link and a second movable link; the second linkage group includes a third movable link and a fourth movable link. The first linkage mechanism, consisting of the base, the first movable link, the second movable link, and the transmission component, is a four-bar linkage mechanism. The second linkage mechanism, consisting of the transmission component, the third movable link, the fourth movable link, and the headrest frame, is also a four-bar linkage mechanism. The locking link is the fourth movable link, and the passive link is the second movable link.

[0019] Preferably, the transmission component includes a first rotation point, a second rotation point, and a third rotation point, which are arranged in a triangular pattern; the fourth movable link and the second movable link are rotatably connected to the transmission component at the first rotation point, the first movable link is rotatably connected to the transmission component at the second rotation point, and the third movable link is rotatably connected to the transmission component at the third rotation point.

[0020] Preferably, the transmission component is roughly triangular in shape, and has clearance grooves on it to avoid the connecting rod. The shape of the transmission component also corresponds to the distribution of the rotation points, and the clearance grooves allow the connecting rod to move smoothly.

[0021] The design starting point, concept, and beneficial effects of the present invention, which adopts the above technical solution, are as follows: In this headrest, the headrest frame moves together with the headrest bracket. The headrest bracket achieves multi-dimensional movement under the action of the first and second linkage mechanisms. Since both the first and second linkage mechanisms are four-bar linkages, the headrest bracket needs to be rotatably connected to the locking link in the second linkage group when forming the four-bar linkage. Furthermore, when the headrest supports the user's head and neck, both the first and second linkage mechanisms need to be locked together. Simultaneously, the user-controlled locking and unlocking mechanism is located on the headrest bracket for convenient operation. The actual locking and unlocking drive mechanism is rotatably located on the locking link to lock or unlock the two four-bar linkages. This means that when the control mechanism moves the drive mechanism, it must adapt to the rotational movement of the headrest bracket and the locking link. Even if the headrest bracket and the locking link rotate relative to each other, the control mechanism can still be linked with the drive mechanism. Therefore, the control mechanism is equipped with... The first connecting part has a first arc-shaped surface, and the driving member has a second connecting part with a second arc-shaped surface. The first arc-shaped surface and the second arc-shaped surface cooperate with each other to adapt to the relative rotation of the locking link and the headrest frame, keeping the first connecting part and the second connecting part always matched. At the same time, a slot is made in the first arc-shaped surface to form two side walls, and a forward-protruding transmission part is provided on the second arc-shaped surface, so that the transmission part is located between the two side walls. After the operating member and the driving member rotate with the rotation of the locking link and the headrest frame, the transmission part is still located between the two side walls, but the transmission part moves to other positions on the side walls. The transmission part and the side walls can always maintain contact and transmission. When the operating member slides, the side walls can drive the transmission part to move, thereby causing the driving member to rotate. Therefore, the transmission between the operating member and the driving member is not affected by the rotation of the headrest frame, and always plays the role of controlling the locking or unlocking of the headrest. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the headrest with the first and second linkage mechanisms shown in the embodiments of the present invention; Figure 2 In this embodiment of the invention, the headrest is relative to Figure 1 Schematic diagram of the three-dimensional structure after movement Figure 1 ; Figure 3 In this embodiment of the invention, the headrest is relative to Figure 1 Schematic diagram of the three-dimensional structure after movement Figure 2 ; Figure 4 This is a three-dimensional structural diagram of the locking mechanism and adjustment device in an embodiment of the present invention; Figure 5 The headrest of the third linkage mechanism is shown in the embodiment of the present invention as a side view; Figure 6 In this embodiment of the invention, the headrest is relative to Figure 5 Side view after exercise Figure 1 ; Figure 7 In this embodiment of the invention, the headrest is relative to Figure 5 Side view after exercise Figure 2 ; Figure 8 This is a three-dimensional structural diagram of the transmission component in an embodiment of the present invention; Figure 9 This is a three-dimensional structural diagram of the base in an embodiment of the present invention; Figure 10 This is a three-dimensional structural diagram of the moving parts and the pillow frame in the embodiments of the present invention; Figure 11 This is a bottom view of the transmission connection between the driving component and the operating component in an embodiment of the present invention; Figure 12 This is a three-dimensional structural diagram of the transmission connection between the driving component and the operating component in an embodiment of the present invention; Figure 13 This is a schematic diagram illustrating the application state of the headrest in an embodiment of the present invention. Figure 1 ; Figure 14 This is a schematic diagram illustrating the application state of the headrest in an embodiment of the present invention. Figure 2 ; Figure 15 This is a schematic diagram illustrating the application state of the headrest in an embodiment of the present invention. Figure 3 ; Figure 16 This is a three-dimensional structural diagram of the locking member and locking part in the adjusting device of the present invention in an embodiment; Figure 17 This is a three-dimensional structural diagram of the first locking member in an embodiment of the present invention.

[0023] The reference numerals in the attached drawings are as follows: base 1; mounting groove 101; arc surface 102; moving part, headrest frame 2; receiving groove 201; protrusion 202; support arm 21; window 22; first movable link 3; second movable link, passive link 4; third movable link 5; fourth movable link, locking link 6; transmission component 9; first rotation point 91; clearance groove 90; first locking part 10; second locking part 11; first locking element 12; first transmission column 121; second locking element 13; second transmission column 131; operating component 14; slide 141; first connecting part 142; first arc surface 143; side wall 144; driving component 15; first waist-shaped groove 151; second waist-shaped groove 152; second connecting part 153; second arc surface 154; transmission part 155; meshing tooth 16; headrest frame 17; lever 18. Detailed Implementation

[0024] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0025] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0026] In the description of this invention, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] The specific embodiments of the present invention are as follows: like Figure 1-4 As shown, the present invention provides a headrest that can adapt to its own rotation to achieve adjustment and locking effects. Specifically, it includes an adjustment device comprising a base 1, a moving component 2, a motion mechanism, and a locking mechanism. The motion mechanism includes a first linkage group, a second linkage group, and a transmission component 9. The two ends of the first linkage group are rotatably connected to the base 1 and the transmission component 9 respectively to form a first linkage mechanism. The two ends of the second linkage group are rotatably connected to the moving component 2 and the transmission component 9 respectively to form a second linkage mechanism. The motion mechanism is configured such that the moving component 2 can move relative to the base 1 in at least two directions. The locking mechanism includes a control component, a first locking element 12, and a second locking element 13. The control component includes an operating element 14 and a driving element 15. The operating element 14 is movably mounted on the moving element 2 or the base 1, and the operating element 14 is connected to the driving element 15 in a transmission manner. The first linkage group or the second linkage group includes a locking linkage 6, and the other linkage group has a passive linkage 4. The driving element 15 is movably mounted on the locking linkage 6. The locking linkage 6 and the passive linkage 4 are rotatably mounted on the transmission element 9 via the same rotating shaft (not shown). The first locking element 12 and the second locking element 13 are both linked with the driving element 15. The passive linkage 4 is provided with a first locking part 10. The first locking element 12 is located beside the first locking part 10. The first locking element 12 is configured to selectively engage with the first locking part 10 to lock as the control component moves. When the first locking element 12 engages with the second locking part 11 to lock, the first linkage mechanism and the second linkage mechanism are locked. When the first linkage mechanism is locked to the second linkage mechanism, the base 1, the first linkage assembly, the second linkage assembly, the transmission component 9, and the moving component 2 form the third linkage mechanism. The moving component 2 or the base 1 is provided with a second locking part 11, and a second locking member 13 is located beside the second locking part 11. The second locking member 13 is configured to selectively cooperate with the second locking part 11 to lock as the control component moves. When the second locking member 13 cooperates with the second locking part 11 to lock, the third linkage mechanism is locked, and the moving component 2 and the base 1 remain stationary.

[0028] The first and second linkage mechanisms are both four-bar linkages, while the third linkage mechanism is a quasi-four-bar linkage. When the adjustment device is not locked, the first and second linkage mechanisms enable the moving part 2 to move in multiple directions relative to the base 1, and it can switch positions within at least one plane, thereby achieving the adjustment function. When the moving part 2 is in motion, the first and second linkage mechanisms together form a double four-bar linkage. Compared with existing technologies, this adjustment device has better adjustment capabilities, mainly reflected in the greater mobility and flexibility of the moving part 2, which better meets the user's multi-purpose needs and is more ergonomic.

[0029] In addition, the locking mechanism of this adjustment device has a simple structure and is ingeniously implemented: Locking link 6 and driven link 4 are rotatably mounted on transmission component 9 via the same rotation axis. This means the first and second link groups share a common rotation point on transmission component 9 (the first rotation point 91), which is also the rotation point of locking link 6 and driven link 4 on transmission component 9. All three are rotatably connected at this point. At this common rotation point, locking link 6, driven link 4, and transmission component 9 all rotate around the same axis. The first locking part 10 and the first locking element 12 are located at this point, enabling simultaneous locking and unlocking of both the first and second link mechanisms.

[0030] Specifically, the driving member 15 is mounted on the locking link 6, and the driving member 15 is linked with the first locking member 12. When the first locking member 12 locks with the first locking part 10 on the passive link 4, the passive link 4 and the driving member 15 are also locked. Similarly, the passive link 4 and the locking link 6 are also locked, and the passive link 4 and the locking link 6 cannot rotate relative to the transmission member 9. Since both the first link mechanism and the second link mechanism are four-bar linkages, both the first link mechanism and the second link mechanism are locked.

[0031] The third linkage mechanism is a four-bar linkage. After the first linkage mechanism and the second linkage mechanism are locked, the locking link 6 and the passive link 4 are equivalent to the same link. Although the mechanism formed by the first link group and the second link group cannot move independently, the third linkage mechanism can still move. Therefore, the second locking member 13 needs to be locked with the second locking part 11 on the base 1 or the moving part 2 in order to completely lock the entire adjustment device and keep the moving part 2 and the base 1 stationary.

[0032] In simple terms, the first locking member 12 and the first locking part 10 can simultaneously lock the first and second linkage mechanisms. At this time, the adjusting device can still move because there is a third linkage mechanism. Therefore, it is further locked by the second locking member 13 and the second locking part 11 to finally lock the adjusting device. Both the first locking member 12 and the second locking member 13 are controlled by the control component. Therefore, the structure of the locking mechanism is ingeniously designed, the locking and unlocking operation is simple and fast, and the support effect after locking is excellent.

[0033] The specific structure of the regulating device is described in further detail below: Specifically, such as Figure 1-7 As shown, the first linkage group includes a first movable link 3 and a second movable link 4; the second linkage group includes a third movable link 5 and a fourth movable link 6. The first linkage mechanism consisting of the base 1, the first movable link 3, the second movable link 4, and the transmission component 9 is a four-bar linkage mechanism, and the second linkage mechanism consisting of the transmission component 9, the third movable link 5, the fourth movable link 6, and the moving component 2 is a four-bar linkage mechanism. The locking link is any one of the first, second, third, and fourth movable links, and the passive link and the locking link are in different linkage groups. Further, the locking link is the fourth movable link 6, and the passive link is the second movable link 4. Therefore, in this scheme, the fourth movable link 6 and the second movable link 4 are rotatably connected to the transmission component 9 at the same rotation point. Positionally, the lower end of the first movable link 3 is rotatably connected to the rear of the base 1, and the upper end of the first movable link 3 is rotatably connected to the rear of the transmission component 9. The lower end of the second movable link 4 is rotatably connected to the front of the base 1, and the upper end of the second movable link 4 is rotatably connected to the rear ends of the transmission component 9 and the fourth movable link 6. The second movable link 4 is located in front of the first movable link 3 and is closer to the moving component 2 than the first movable link 3. The front end of the third movable link 5 is rotatably connected to the upper part of the moving component 2, and the rear end of the third movable link 5 is rotatably connected to the upper part of the transmission component 9. The front end of the fourth movable link 6 is rotatably connected to the lower part of the moving component 2. The fourth movable link 6 is located below the third movable link 5 and is closer to the base 1 than the third movable link 5. The positions of the second movable link 4 and the fourth movable link 6 are more suitable for locking. The rotational connection of the movable links is achieved through the rotating shafts of their respective rotation points.

[0034] To be more specific, such as Figure 8 As shown, the transmission component 9 includes a first rotation point 91, a second rotation point, and a third rotation point, which are arranged in a triangle. The fourth movable link 6 and the second movable link 4 are rotatably connected to the transmission component 9 at the first rotation point 91, the first movable link 3 is rotatably connected to the transmission component 9 at the second rotation point, and the third movable link 5 is rotatably connected to the transmission component 9 at the third rotation point. This scheme specifically sets three rotation points arranged in a triangle on the transmission component 9 to realize the transmission between the first and second linkage mechanisms. When unlocked, the first and second linkage mechanisms can move together and jointly cause the moving component 2 to perform multi-dimensional motion. The first rotation point 91 is the common rotation point, and the rotation shaft is located here. The transmission component 9 is roughly triangular in shape, and a clearance groove 90 is provided on the transmission component 9 to avoid the connecting rods. The shape of the transmission component 9 also corresponds to the distribution of the rotation points, and the clearance groove 90 allows the connecting rods to move smoothly.

[0035] Both the first and second linkage mechanisms are four-bar linkages, offering more refined and fluid motion compared to existing technologies. Specifically, in one type of existing mechanism, two oscillating rods are sequentially connected to a base, enabling movement of the moving component relative to the base in two directions. However, this dual-oscillating-rod type mechanism suffers from a limited motion trajectory, concentrated load leading to wear, and a limited range of motion restricted by rod length, resulting in poor flexibility. In contrast, the proposed double four-bar linkage offers controllable motion trajectories, allowing for the design of complex trajectories such as straight lines, ellipses, and specific curves. Multiple rods distribute the load, reducing stress concentration and improving load-bearing capacity and service life. More importantly, it offers high customizability; by pre-setting the trajectory according to requirements, it achieves a wider range of motion coverage, resulting in more refined and flexible motion that broadly meets user needs. The four-bar linkage demonstrates significant advantages in motion complexity, load capacity, and dynamic performance, making it a superior solution for applications requiring high control accuracy and reliability.

[0036] Regarding locking: such as Figure 1 , 4As shown in Figures 5, 16, and 17, when the first linkage mechanism is locked to the second linkage mechanism, the second movable link 4 and the fourth movable link 6 are also locked. The base 1, the first movable link 3, the transmission component 9, the third movable link 5, the moving component 2, and the second movable link 4 and the fourth movable link 6 form the third linkage mechanism. Even when only the second movable link 4 and the fourth movable link 6 are locked, the third linkage mechanism remains a movable, four-bar linkage-like mechanism. The moving component 2 is not fully locked at this time. Therefore, in addition to locking the first and second linkage mechanisms, the second locking component 13 and the second locking part 11 are also required to lock the third linkage mechanism. Furthermore, when the first locking component 12 and the second locking component 13 simultaneously lock or unlock, the first, second, and third linkage mechanisms will be locked or unlocked synchronously.

[0037] Specifically, the operating component 14 is slidably mounted on the moving component 2. While controlling the movement of the moving component 2, the user can also control the operating component 14 to switch between unlocked and locked states, which can be completed with one hand, making operation more convenient. The driving component 15 is rotatably connected to the fourth movable link 6 in the middle. The two ends of the driving component 15 are respectively connected to the first locking component 12 and the second locking component 13. The driving component 15 is rotatably mounted on the fourth movable link 6. When the driving component 15 rotates, its two ends rotate together. Since the first and second locking components are connected to the two ends of the driving component 15, the first and second locking components 12 and 13 will move together to lock or unlock. That is, the state switching of the first, second and third linkage mechanisms can be controlled simultaneously, thereby realizing the unlocking and locking of the moving component 2 in one step. The driving component 15 has a first waist-shaped groove 151 and a second waist-shaped groove 152. The first locking component 12 has a first transmission column 121, and the second locking component 13 has a second transmission column 131. The first transmission column 121 is inserted into the first waist-shaped groove 151, and the second transmission column 131 is inserted into the second waist-shaped groove 152. The driving component 15 and the locking component are connected by the waist-shaped grooves and the transmission columns, resulting in a simple structure. Moreover, even if the motion mechanism changes its posture after movement, the transmission column can still remain in the waist-shaped groove.

[0038] One end of the locking link 6 is inserted with a rotating shaft, and the other end is inserted with a first rotating shaft (not shown). The locking link 6 is rotatably connected to the base 1 or the moving part 2 via the first rotating shaft. The first locking member 12 is slidably disposed on the rotating shaft, and the second locking member 13 is slidably disposed on the first rotating shaft. In this design, the locking link is a fourth movable link 6, which is rotatably connected to the moving part 2 via the first rotating shaft. The first locking part 10 is disposed on the second movable link 4, and the second locking part 11 is disposed on the moving part 2. Under the action of the driving member 15, the first locking member 12 and the second locking member 13 slide on the rotating shaft and the first rotating shaft to achieve locking and unlocking. In addition, a circumferential limiting structure needs to be provided between the first locking member 12, the second locking member 13, and the locking link 6 to maintain the synchronous rotation of the first locking member 12, the second locking member 13, and the locking link 6. The circumferential limiting structure can be a convex-groove structure, etc. Furthermore, since the middle part of the drive member 15 rotates and the two locking members are located on both sides of the drive member 15, the sliding directions of the two locking members are opposite when the drive member 15 rotates. Therefore, the orientation directions of the first locking member 12 and the second locking member 13 should also be opposite.

[0039] The locking elements and locking parts achieve selective locking through meshing teeth 16: The first locking element 12, the second locking element 13, the first locking part 10, and the second locking part 11 all have a plurality of meshing teeth 16 evenly distributed circumferentially. The meshing teeth 16 are all located on the end face of their respective components. The first locking element 12 selectively engages with the first locking part 10, and the second locking element 13 selectively engages with the second locking part 11. The meshing locking of the locking elements and locking parts is achieved through the meshing teeth 16 evenly distributed circumferentially on the same plane. A spring (not shown) is also fitted on the first rotating shaft on which the second locking element 13 is mounted. The spring always provides a spring force to the second locking element towards the second locking part 11. When the user does not control the movement of the operating element 14, the first and second locking elements are always locked with the first and second locking parts. When the user controls the movement of the operating element 14, the driving element 15 rotates and counteracts the spring force to make the lock engage, thus making operation easier and simpler.

[0040] In addition, such as Figure 9 As shown, the first movable link 3 has a backward-protruding curved arc, meaning the first movable link 3 bends from bottom to top and forward. A mounting groove 101 is provided on the base 1, and the lower end of the first movable link 3 is positioned in the mounting groove 101. The end face of the mounting groove 101 away from the first movable link 3 is an arc surface 102. The arc surface 102 adapts to the bending of the first movable link 3, and in conjunction with the bent first movable link 3, it can be used to increase the rotation angle, thereby solving the problem of the straight rod colliding with the base 1, causing motion interference, and the problem of the rotation angle being too small.

[0041] like Figure 1-3As shown in Figures 13-15, this adjustment device is applied to a headrest, which includes a head support assembly and the aforementioned adjustment device. The head support assembly includes a headrest frame 17 and a headrest bracket 2. The headrest frame 17 is rotatably mounted on the headrest bracket 2 about a left-right axis. The headrest frame 17 is configured to fit against and support the human head and neck. The headrest bracket 2 is the moving part, and the base 1 is configured to be connected to the back of the seat. When the headrest bracket 2 moves relative to the base 1, the headrest bracket 2 drives the headrest frame 17 to move together.

[0042] This headrest features adjustable movement and support via the aforementioned adjustment mechanism, allowing for multi-dimensional movement and varied postures to adapt to the different needs of various users. Users can obtain more reasonable and comfortable head and neck support, conforming to ergonomic principles. The headrest frame 17 can also rotate relative to the headrest frame 2, adapting to the curve and tilt angle of the human head and neck. When the headrest frame 2 is locked, the movement of the headrest frame 17 is also locked. Furthermore, the headrest frame 17 can adaptively rotate relative to the headrest frame 2 to conform to the human head and neck; even when the movement of the headrest frame 17 is locked, it can still rotate. This adjustment mechanism can also be applied to lumbar supports.

[0043] In addition, such as Figure 10 As shown, the pillow frame 2 has a receiving groove 201, and the operating member 14 is slidably disposed in the receiving groove 201. The pillow frame 2 has a downwardly protruding protrusion 202, and the operating member 14 has a vertically penetrating sliding groove 141. The protrusion 202 is inserted into the sliding groove 141, making the operating member 14 slide more stably on the pillow frame 2. Furthermore, the operating member 14 is also provided with a lever 18. The pillow frame 2 includes two side-by-side support arms 21, one of which has a window 22. The lever 18 passes through the window 22 and connects to the operating member 14, making operation more convenient.

[0044] like Figure 11 , 12As shown, the driving component 15 is rotatably mounted on the fourth movable link 6, and the operating component 14 is movably mounted on the headrest frame 2. The operating component 14 is connected to the driving component 15, but the headrest frame 2 and the fourth movable link 6 will also rotate relative to each other. At this time, the transmission between the driving component 15 and the operating component 14 must also adapt to the rotation of the fourth movable link 6 and the headrest frame 2. Specifically, the rear end of the operating component 14 is provided with a first connecting part 142, and the front end of the driving component 15 is provided with a second connecting part 153. The first connecting part 142 has a first arc-shaped surface 143 facing the second connecting part 153, and the second connecting part 153 has a corresponding second arc-shaped surface 154. The two cooperate with each other so that the driving component 15 and the operating component 14 can adapt to the relative rotation of the fourth movable link 6 and the headrest frame 2. A groove is made in the first arc-shaped surface 143 on the first connecting part 142, forming two sidewalls 144 in the groove. The sidewalls 144 are naturally located beside the first arc-shaped surface 143 and are further forward relative to the first arc-shaped surface 143. A spherical transmission part 155 protrudes from the second arc-shaped surface 154 of the second connecting part 153. The spherical transmission part 155 protrudes forward from the second arc-shaped surface 154 and is located between the two side walls 144. When the headrest frame 2 and the fourth movable connecting rod 6 rotate, the transmission part 155 rotates between the two side walls 144, and the two are configured to abut against each other for transmission. That is, when the operating member 14 slides, the transmission part 155 can be pushed to move by the side wall 144 at any position of the side wall 144, so that the sliding of the operating member 14 can always be transmitted to the driving member 15.

Claims

1. A headrest, characterized in that: The device includes a base for connecting to the back of a seat, a first linkage group connected to the base, a transmission component connected to the other end of the first linkage group, a second linkage group connected to the other end of the transmission component, and a headrest frame connected to the other end of the second linkage group. The headrest frame is provided with a headrest frame for conforming to and supporting the head and neck of the user. The base, the first linkage group, and the transmission component constitute the first linkage mechanism, and the transmission component, the second linkage group, and the headrest frame constitute the second linkage mechanism. Both the first and second linkage mechanisms are four-bar linkage mechanisms. The headrest frame moves relative to the base through the first and second linkage mechanisms, and the movement of the headrest frame drives the headrest frame to move together. The second linkage group includes a locking linkage, a headrest frame rotatably connected to the locking linkage, a driving member rotatably provided on the locking linkage, an operating member slidably provided on the headrest frame, the operating member being connected to the driving member in a transmission manner, and the operating member being configured to control the rotation of the driving member relative to the locking linkage and simultaneously lock or unlock the movement of the first and second linkage mechanisms. The operating component has a first connecting part at its rear end and a second connecting part at its front end. The first connecting part has a first arc-shaped surface facing the second connecting part, and the second connecting part has a corresponding second arc-shaped surface. The first and second arc-shaped surfaces cooperate with each other to allow the driving component and the operating component to adapt to the relative rotation of the locking link and the headrest frame. A groove is made on the first arc-shaped surface of the first connecting part to form two sidewalls. A transmission part is protruding forward on the second arc-shaped surface of the second connecting part. The transmission part is located between the two sidewalls and is configured to abut against the sidewalls for transmission. When the operating component slides, the sidewalls can push the transmission part to move at any position of the transmission part, so that the sliding of the operating component can always be transmitted to the driving component.

2. The headrest according to claim 1, characterized in that: The side wall is located beside the first arc-shaped surface and is further forward relative to the first arc-shaped surface; when the headrest frame and the locking linkage rotate, the transmission part rotates between the two side walls.

3. The headrest according to claim 1, characterized in that: The transmission part is spherical.

4. The headrest according to claim 1, characterized in that: The pillow frame has a receiving groove, and the operating component is slidably disposed in the receiving groove.

5. The headrest according to claim 1, characterized in that: The first linkage group includes a passive linkage and a locking linkage. The passive linkage and the locking linkage are rotatably mounted on the transmission component via the same rotating shaft. The driving component is linked with a first locking component and a second locking component. The passive linkage is provided with a first locking part, and the first locking component is located beside the first locking part. The headrest frame is provided with a second locking part, and the second locking component is located beside the second locking part. The first locking component and the second locking component move closer to or away from the corresponding locking part as the driving component rotates. When the first locking component and the second locking component simultaneously approach the corresponding locking part and lock into the corresponding locking part, the movement of the first linkage mechanism and the second linkage mechanism is locked at the same time, and the relative position of the headrest frame and the base is locked.

6. The headrest according to claim 5, characterized in that: The middle part of the drive component is rotatably connected to the locking link, and the two ends of the drive component are respectively connected to the first locking component and the second locking component. When the drive component rotates, it simultaneously controls the movement of the first locking component and the second locking component.

7. The headrest according to claim 6, characterized in that: The driving component has a first waist-shaped groove and a second waist-shaped groove. The first locking component has a first transmission column, and the second locking component has a second transmission column. The first transmission column is inserted into the first waist-shaped groove, and the second transmission column is inserted into the second waist-shaped groove.

8. The headrest according to claim 5, characterized in that: One end of the locking link is inserted with a rotating shaft, and the other end of the locking link is inserted with a first rotating shaft. The locking link is rotatably connected to the pillow frame through the first rotating shaft. The first locking member is slidably disposed on the rotating shaft, and the second locking member is slidably disposed on the first rotating shaft.

9. The headrest according to claim 5, characterized in that: The first locking member, the second locking member, the first locking part, and the second locking part are all evenly distributed with a number of meshing teeth along the circumference. The first locking member and the first locking part selectively engage and lock, and the second locking member and the second locking part selectively engage and lock.

10. The headrest according to claim 5, characterized in that: The first linkage group includes a first movable link and a second movable link; the second linkage group includes a third movable link and a fourth movable link. The first linkage mechanism, consisting of the base, the first movable link, the second movable link, and the transmission component, is a four-bar linkage mechanism. The second linkage mechanism, consisting of the transmission component, the third movable link, the fourth movable link, and the headrest frame, is also a four-bar linkage mechanism. The locking link is the fourth movable link, and the passive link is the second movable link.

11. The headrest according to claim 10, characterized in that: The transmission component includes a first rotation point, a second rotation point, and a third rotation point, which are arranged in a triangular pattern. The fourth movable link and the second movable link are rotatably connected to the transmission component at the first rotation point, the first movable link is rotatably connected to the transmission component at the second rotation point, and the third movable link is rotatably connected to the transmission component at the third rotation point.

12. The headrest according to claim 11, characterized in that: The transmission component is roughly triangular in shape, and a clearance groove for the clearance connecting rod is provided on the transmission component.

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