Mechanical stretching device for movable seat unit, and movable seat unit

Abstract

The present application relates to a mechanical stretching device (1) for a movable seat unit, the mechanical stretching device being capable of switching between a sitting position, a TV position and a lying position. The mechanical stretching device comprises: a fixed plate (12); a seat frame (10) capable of moving back and forth relative to the fixed plate (12); a backrest assembly (2) connected to the rear of the seat frame (10); and a leg stretching device (3) connected to the front of the seat frame (10), wherein when being in the lying position, the leg stretching device (3) stretches forwards and upwards, and the highest point of the leg stretching device (3) is at least 300 mm higher than the highest point of a backrest support (21).

Description

Mechanical extension device for a movable seat unit and movable seat unit Technical Field

[0001] The present application relates to a mechanical extension device for a movable seating unit and a movable seating unit comprising the mechanical extension device. Background Art

[0002] Various movable seating systems are known in the prior art, such as sofas or chairs with multi-position conversion capabilities. As people's living standards improve, the demand for comfort in sofas and chairs is also increasing. In known designs, movable seating units typically include a mechanical extension mechanism, enabling them to be converted between a stowed position, a TV-posture position, and a reclining position. When the seat is converted from the stowed position to the TV-posture position, the footrest of the seating unit extends forward, and the angle between the backrest and the seat remains substantially unchanged. When the seat is converted from the lounge position to the reclining position, the footrest is raised further forward and upward than in the lounge position, and the backrest reclines significantly.

[0003] Existing designs for this type of chair often require numerous mechanical structures with complex connections, and sometimes even lead to stagnation in chair posture changes due to poor design. Furthermore, as users' demands for comfort continue to rise and they pursue zero-wall configurations, existing movable chair designs cannot fully meet users' needs for comfort and space conservation. In particular, in the reclining position, zero-wall design chairs often fail to fully elevate the user's legs to a comfortable height, resulting in a lack of comfort.

[0004] Application Contents

[0005] The technical problem to be solved by the present application is to provide a mechanical extension device for a movable seat unit and a corresponding movable seat unit, which have a compact structure and improved comfort.

[0006] To solve the above technical problems, the present application provides a mechanical extension device for a movable seat unit, wherein the mechanical extension device can be transformed between a sitting position, a TV position, and a lying position, and the mechanical extension device comprises:

[0007] -Fixed plate;

[0008] - a seat frame movable forward and backward relative to the fixed plate for attaching the seat portion of the movable seat;

[0009] - a backrest assembly connected to the rear portion of the seat frame, the backrest assembly comprising a backrest bracket, a backrest link and a bellcrank, wherein the backrest bracket is used to attach the backrest of the seat unit, the backrest bracket being pivotally connected to the seat frame by means of the backrest link and the bellcrank so that the rearmost end of the backrest bracket has a tendency to move forward during the transformation of the mechanical extension device from the sitting position to the lying position; and

[0010] - Leg extensions connected to the front of the seat frame.

[0011] According to the present application, in the lying position, the leg extension device is extended forward and upward, and the highest point of the leg extension device is at least 300 mm higher than the highest point of the backrest support.

[0012] In some embodiments, in the reclining position, the highest point of the leg extension is at least 370 mm higher than the highest point of the back support.

[0013] In some embodiments, the backrest link includes a first pivot point at an upper end thereof and a second pivot point at a lower end thereof, wherein the backrest link is pivotally connected to the front end of the backrest support at the first pivot point and is pivotally connected to the seat frame at the second pivot point. In the sitting position, a line connecting the first pivot point and the second pivot point forms a first angle with respect to an upper surface of the seat frame that opens toward the leg extension, and in the sitting position, the first angle is greater than 90°. In some embodiments, the first angle is between 95° and 130° in the sitting position.

[0014] In some embodiments, the front side of the backrest frame forms a second angle with the ground, opening toward the leg extension device, and the second angle increases by at least 35° in the reclining position compared to the sitting position. In some embodiments, the second angle increases by at least 45° in the reclining position compared to the sitting position.

[0015] In some embodiments, the crank member includes three pivot points, namely a third pivot point, a fourth pivot point and a fifth pivot point, wherein the third pivot point and the fifth pivot point are respectively located on the upper end and the lower end of the crank member, and the fourth pivot point is located between the third pivot point and the fifth pivot point, wherein the crank member is pivotally connected to the rear end of the backrest bracket at the third pivot point, is pivotally connected to the seat frame at the fourth pivot point, and is at least indirectly coupled to the fixed plate at the fifth pivot point.

[0016] In some embodiments, the seat frame is attached to the fixed plate so as to be movably forward and backward via a primary linkage assembly and a secondary linkage assembly, wherein the seat frame is pivotally connected to the primary linkage assembly, and the secondary linkage assembly is pivotally connected to the fixed plate.

[0017] In some embodiments, the main linkage assembly includes a front swing rod, a rear swing rod and an intermediate linkage pivotally connected to the secondary linkage assembly. During the process of the mechanical extension device changing from the sitting position to the TV position, the rear end of the seat frame is driven by the main linkage assembly to move downward and forward relative to the intermediate linkage, wherein the intermediate linkage has no relative displacement relative to the fixed plate; during the process of the mechanical extension device changing from the TV position to the lying position, the seat frame is driven by the secondary linkage assembly to move forward and upward relative to the fixed plate together with the main linkage assembly.

[0018] In some embodiments, the upper ends of the front swing link and the rear swing link are pivotally connected to the seat frame, the lower end of the front swing link is pivotally connected to the intermediate link at a sixth pivot point, and the lower end of the rear swing link is pivotally connected to the intermediate link at a seventh pivot point.

[0019] In some embodiments, the secondary linkage assembly includes a secondary front swing rod, a secondary rear swing rod, a secondary front linkage rod, a secondary rear linkage rod, a secondary intermediate linkage rod and a follower linkage rod, wherein the lower end of the secondary rear linkage rod is pivotally connected to the rear end of the intermediate linkage rod at an eighth pivot point, the top end of the secondary rear linkage rod is pivotally connected to the middle part of the secondary rear swing rod at a ninth pivot point, and the rear end of the secondary intermediate linkage rod is pivotally connected to the middle part of the secondary rear linkage rod at a tenth pivot point.

[0020] In some embodiments, the seventh pivot point is located between the sixth pivot point and the eighth pivot point, wherein a ratio of a distance between the eighth pivot point and the seventh pivot point to a distance between the sixth pivot point and the eighth pivot point is no greater than 0.35.

[0021] In some embodiments, the tenth pivot point is located between the eighth pivot point and the ninth pivot point, wherein the ratio of the distance between the ninth pivot point and the tenth pivot point to the distance between the eighth pivot point and the tenth pivot point is no more than 1.

[0022] In some embodiments, the top end of the secondary front swing link is pivotally connected to the front end of the secondary intermediate link, the lower end of the secondary front swing link is pivotally connected to the fixed plate, the top end of the secondary rear swing link is pivotally connected to the rear end of the follower link at an eleventh pivot point, and the lower end of the secondary rear swing link is pivotally connected to the fixed plate at a twelfth pivot point.

[0023] In some embodiments, the ninth pivot point is located between the eleventh pivot point and the twelfth pivot point, wherein the ratio of the distance between the eleventh pivot point and the ninth pivot point to the distance between the twelfth pivot point and the ninth pivot point is no greater than 1.

[0024] As a result, in the sitting position, the first angle formed by the line connecting the first pivot point at the upper end of the backrest link and the second pivot point at its lower end with the upper surface of the seat frame is obtuse. However, in the reclining position, this angle becomes acute. This design allows the upper end of the backrest link to traverse a larger arc when the seat unit transitions from a sitting position to a reclining position. This not only allows the backrest bracket coupled to the backrest link to move forward with a greater amplitude, i.e., toward the leg extension, thereby achieving a completely zero-wall position, but also, because the lower edge of the seat back, to which the backrest bracket is attached, is located at the upper end of the backrest link, it protrudes further forward and upward during the transition from a sitting position to a reclining position, providing sufficient support for the user's lumbar region. This lumbar support, in particular, overcomes the ergonomic discomfort of having the lumbar region suspended in the air, providing stronger and more comfortable support for the user's lumbar region.

[0025] In addition, through the reasonable design of the pivot points between the intermediate connecting rod, the auxiliary rear swing rod and the auxiliary rear linkage rod, the smoothness of the seat unit in the process of changing different postures is ensured, mechanical jamming is avoided, and the maximum height that the mechanical extension device and the related leg extension device of the seat unit can reach in the lying position is increased, thereby achieving an improved zero-gravity posture.

[0026] To solve the above technical problems, the present application further provides a movable chair unit, comprising a mechanical extension device, an armrest portion, a backrest portion, and a seat portion attached to the mechanical extension device, wherein the mechanical extension device is capable of transforming the chair unit between a sitting position, a TV position, and a lying position, and the mechanical extension device comprises:

[0027] -Fixed plate;

[0028] - a seat frame movable forward and backward relative to the fixing plate for attaching the seat portion;

[0029] - a backrest assembly connected to the rear portion of the seat frame, the backrest assembly comprising a backrest bracket, a backrest link and a bellcrank, wherein the backrest bracket is used to attach the backrest, the backrest bracket being pivotally connected to the seat frame by means of the backrest link and the bellcrank so that the rearmost end of the backrest bracket has a tendency to move forward during the transformation of the mechanical extension device from the sitting position to the lying position; and

[0030] - Leg extensions connected to the front of the seat frame.

[0031] According to the present application, in the lying position, the leg extension device is extended forward and upward, and the highest point of the leg extension device is at least 300 mm higher than the highest point of the backrest support.

[0032] In some embodiments, in the reclining position, the highest point of the leg extension is at least 370 mm higher than the highest point of the back support.

[0033] In some embodiments, the backrest link includes a first pivot point at an upper end thereof and a second pivot point at a lower end thereof, wherein the backrest link is pivotally connected to the front end of the backrest support at the first pivot point and is pivotally connected to the seat frame at the second pivot point. In the sitting position, a line connecting the first pivot point and the second pivot point forms a first angle with respect to an upper surface of the seat frame that opens toward the leg extension, and in the sitting position, the first angle is greater than 90°. In some embodiments, the first angle is between 95° and 130° in the sitting position.

[0034] In some embodiments, the front side of the backrest frame forms a second angle with the ground, opening toward the leg extension device, and the second angle increases by at least 35° in the reclining position compared to the sitting position. In some embodiments, the second angle increases by at least 45° in the reclining position compared to the sitting position.

[0035] In some embodiments, the crank member includes three pivot points, namely a third pivot point, a fourth pivot point and a fifth pivot point, wherein the third pivot point and the fifth pivot point are respectively located on the upper end and the lower end of the crank member, and the fourth pivot point is located between the third pivot point and the fifth pivot point, wherein the crank member is pivotally connected to the rear end of the backrest bracket at the third pivot point, is pivotally connected to the seat frame at the fourth pivot point, and is at least indirectly coupled to the fixed plate at the fifth pivot point.

[0036] In some embodiments, the seat frame is attached to the fixed plate so as to be movably forward and backward via a primary linkage assembly and a secondary linkage assembly, wherein the seat frame is pivotally connected to the primary linkage assembly, and the secondary linkage assembly is pivotally connected to the fixed plate.

[0037] In some embodiments, the main linkage assembly includes a front swing rod, a rear swing rod and an intermediate linkage pivotally connected to the secondary linkage assembly. During the process of the mechanical extension device changing from the sitting position to the TV position, the rear end of the seat frame is driven by the main linkage assembly to move downward and forward relative to the intermediate linkage, wherein the intermediate linkage has no relative displacement relative to the fixed plate; during the process of the mechanical extension device changing from the TV position to the lying position, the seat frame is driven by the secondary linkage assembly to move forward and upward relative to the fixed plate together with the main linkage assembly.

[0038] In some embodiments, the upper ends of the front swing link and the rear swing link are pivotally connected to the seat frame, the lower end of the front swing link is pivotally connected to the intermediate link at a sixth pivot point, and the lower end of the rear swing link is pivotally connected to the intermediate link at a seventh pivot point.

[0039] In some embodiments, the secondary linkage assembly includes a secondary front swing rod, a secondary rear swing rod, a secondary front linkage rod, a secondary rear linkage rod, a secondary intermediate linkage rod and a follower linkage rod, wherein the lower end of the secondary rear linkage rod is pivotally connected to the rear end of the intermediate linkage rod at an eighth pivot point, the top end of the secondary rear linkage rod is pivotally connected to the middle part of the secondary rear swing rod at a ninth pivot point, and the rear end of the secondary intermediate linkage rod is pivotally connected to the middle part of the secondary rear linkage rod at a tenth pivot point.

[0040] In some embodiments, the seventh pivot point is located between the sixth pivot point and the eighth pivot point, wherein a ratio of a distance between the eighth pivot point and the seventh pivot point to a distance between the sixth pivot point and the eighth pivot point is no greater than 0.35.

[0041] In some embodiments, the tenth pivot point is located between the eighth pivot point and the ninth pivot point, wherein the ratio of the distance between the ninth pivot point and the tenth pivot point to the distance between the eighth pivot point and the tenth pivot point is no more than 1.

[0042] In some embodiments, the top end of the secondary front swing link is pivotally connected to the front end of the secondary intermediate link, the lower end of the secondary front swing link is pivotally connected to the fixed plate, the top end of the secondary rear swing link is pivotally connected to the rear end of the follower link at an eleventh pivot point, and the lower end of the secondary rear swing link is pivotally connected to the fixed plate at a twelfth pivot point.

[0043] In some embodiments, the ninth pivot point is located between the eleventh pivot point and the twelfth pivot point, wherein the ratio of the distance between the eleventh pivot point and the ninth pivot point to the distance between the twelfth pivot point and the ninth pivot point is no greater than 1.

[0044] It should be noted here that the "front and rear directions" mentioned in this application refer to the extension direction of the leg extension device of the seat unit or the mechanical extension device. Specifically, "front" refers to the direction toward the leg extension device, and "rear" refers to the direction toward the backrest.

[0045] The advantages described above with respect to the mechanical extension device also apply to a movable seat unit having such a mechanical extension device. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The embodiments of the present application are explained in detail below with reference to the accompanying drawings.

[0047] FIG1 schematically shows a partial perspective view of a seat unit according to the present application;

[0048] FIG2 schematically shows in perspective a mechanical extension device for a movable seat unit according to one embodiment of the present application, in a sitting position;

[0049] FIG3 schematically illustrates in a perspective view the TV posture position of the mechanical stretching device shown in FIG2 ;

[0050] FIG4 schematically shows in a perspective view the lying position of the mechanical stretching device shown in FIG2 ;

[0051] FIG5 shows a side view of the mechanical extension device shown in FIG2 in a sitting position;

[0052] FIG6 schematically illustrates, in side view, the TV posture position of the mechanical stretching device shown in FIG2 ;

[0053] FIG7 schematically shows, in side view, the lying position of the mechanical stretching device shown in FIG2 ;

[0054] FIG8 shows a side view of a mechanical extension device according to an embodiment of the present application from another angle, in a sitting position;

[0055] FIG9 schematically shows a side view of the mechanical extension device shown in FIG8 in the TV posture position;

[0056] FIG10 schematically shows a side view of the mechanical extension device shown in FIG8 in a lying position;

[0057] FIG11 schematically shows a partial enlarged view of the mechanical stretching device shown in FIG7 ;

[0058] FIG12 shows a partial enlarged view of the mechanical stretching device shown in FIG11 from another angle; and

[0059] FIG. 13 schematically shows a position change diagram of a seat unit according to the present application. DETAILED DESCRIPTION

[0060] As used herein, "one embodiment" or "an embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present application. Throughout the description of this application, it should be understood that the terms "upper," "lower," "left," "right," "top," "bottom," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplification. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and are therefore not to be construed as limiting the present application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Thus, a feature designated "first" or "second" may explicitly or implicitly include one or more of the features. Furthermore, the terms "first," "second," and the like are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential sequence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0061] Figure 1 schematically shows a partial stereoscopic view of a movable seat unit according to the present application; Figures 2 to 4 show the mechanical extension device 1 of the movable seat unit according to the present application in stereoscopic form, and Figures 5 to 7 show the mechanical extension device of the seat unit according to the present application in side view form.

[0062] The seat unit comprises a mechanical extension device 1 and a frame structure 6 .

[0063] The mechanical extension device 1 includes a multi-link mechanism and is configured to enable the movable seat to be shifted between a sitting position, a TV position, and a reclining position. However, the present application is not limited thereto. In other embodiments (not shown), the movable seat may be shifted only between a stowed position and a TV position, or only between a stowed position and a reclining position.

[0064] As shown in Figures 1 to 7, a mechanical extender 1 is configured for a movable seat unit with floor-standing armrests. It comprises two mirror-symmetrically arranged mechanical extender halves, each with a fixing plate 12 extending longitudinally in the front-to-rear direction of the movable seat unit. A frame structure 6 comprises two mirror-symmetrically arranged armrest frames 60 and a backrest frame 61 extending movably between the two armrest frames. Each mechanical extender half is positioned on the inner side of the armrest frame 60 via its respective fixing plate 12. An armrest portion 602 is fixedly attached to the outer side of the armrest frame 60. Thus, the fixing plate 12 is fixedly connected to the armrest portion 602. Specifically, the fixing plate 12 is fixedly connected to the armrest frame 60 using front and rear mounting holes 12a and 12b. Furthermore, each fixing plate 12 is attached to a common fixing beam 52 located on the backrest side, i.e., the rear portion of the movable seat unit, via fixing tabs 51. The bottom of the armrest frame 60 is respectively provided with a support 601, by means of which the entire seat unit is supported on the ground, so that the mechanical extension device is supported "suspended" above the ground.

[0065] The mechanical stretching device 1 further includes a seat frame 10 , a backrest assembly 2 pivotally connected to the rear portion of the seat frame 10 , and a leg stretching device 3 pivotally connected to the front portion of the seat frame 10 .

[0066] The seat frame 10 is used to support the seat portion (not shown) of the movable seat unit, and the seat frame 10 includes an upwardly extending seat frame extension portion 11 fixedly arranged at the rear thereof. The seat frame extension portion 11 can be integrally formed with the main portion of the seat frame, or can be fixedly connected thereto as a separate component, for example, it can be fixedly installed by welding, riveting, etc.

[0067] The backrest assembly 2 includes a backrest bracket 21 for attaching a backrest (not shown) using a backrest frame 61 , a backrest link 22 and a bellcrank 23 .

[0068] The backrest bracket 21 is generally L-shaped, with its upper portion fixedly connected to the backrest frame 61. A backrest link 22 is connected between its front end and the seat frame 10, and a crank member 23 is connected between its rear end and the seat frame 10. The backrest is fixedly mounted on the front side of the backrest frame 61, that is, facing the leg extension of the seat unit.

[0069] The upper end of the backrest link 22 is pivotally connected to the front end of the backrest bracket 21 at a first pivot point P1, and the lower end thereof is pivotally connected to the rear end of the seat frame 10 at a second pivot point P2.

[0070] The crank member 23 includes three pivot points: a third pivot point P3, a fourth pivot point P4, and a fifth pivot point P5. The third pivot point P3 is located at the upper end of the crank member 23, the fifth pivot point P5 is located at the lower end, and the fourth pivot point P4 is located in the middle of the crank member 23, located between the third pivot point P3 and the fifth pivot point P5. The crank member 23 is pivotally connected to the rear end of the backrest bracket 21 at the third pivot point P3 at its upper end. The crank member 23 is pivotally connected to the upper end of the seat frame rear extension 11 at its middle portion at the fourth pivot point P4, thereby pivotally connecting to the rear end of the seat frame 10. The fourth pivot point P4 is located further rearward than the second pivot point P2, that is, farther from the leg extension 3 when viewed in the fore-aft direction of the seat. Furthermore, the crank member 23 is pivotally connected at its lower end to the upper end of the fixed plate link 24 at a fifth pivot point P5 , and the lower end of the fixed plate link 24 is pivotally connected to the rear portion of the fixed plate 12 .

[0071] To make the seat unit's posture change smoother, the ratio of the second distance L2 to the third distance L3 is set to 0.4 to 1.0. In a particularly preferred embodiment, the ratio of the second distance L2 to the third distance L3 is preferably 0.6 to 0.8. The ratio of the first distance L1 to the second distance L2 is set to 0.6 to 1.2. In a particularly preferred embodiment, the ratio of the first distance L1 to the second distance L2 is set to 0.7 to 1.0.

[0072] Furthermore, in the sitting position shown in FIG5 , the first pivot point P1 of the backrest link 22 is positioned horizontally further rearward relative to the second pivot point P2, that is, closer to the backrest. Consequently, the line connecting the first and second pivot points P1 and P2 forms a rearward angle γ with respect to a vertical line E0 passing through the second pivot point P2. In the sitting position shown in FIG7 , the first pivot point P1 of the backrest link 22 is positioned horizontally further forward relative to the second pivot point P2, that is, closer to the leg extension mechanism. Consequently, the line connecting the first and second pivot points P1 and P2 forms a forward angle γ with respect to a vertical line E0 passing through the second pivot point P2. As shown in FIG8 , the line connecting the first and second pivot points P1 and P2 of the backrest link 22 forms a first angle α with respect to the upper surface of the seat frame 10, opening toward the leg extension mechanism 3. In the sitting position, the first angle α is greater than 90°, and preferably between 95° and 130°.

[0073] This design allows the backrest link 22 to pivot forward at a greater angle when the mechanical extension device 1 transitions from a sitting position to a reclining position. This not only closes the gap that might otherwise exist between the backrest and the seat, preventing the user's clothing from being pulled out, but also allows the backrest bracket 21 to move forward at a greater extent as it pivots rearward about the first pivot point P1, eliminating interference between the backrest and the rear wall and achieving a completely zero-wall-relaxation position.

[0074] The front side of the backrest bracket 21 forms a second angle β with the ground or a horizontal reference plane parallel to the ground. In the embodiments shown in Figures 8 and 10, the horizontal plane at the center of the rear mounting hole 12b of the fixing plate 12 is the horizontal reference plane E1. During the transition from a sitting position to a lying position, the backrest bracket 21 tilts rearward at a larger angle, wherein the second angle β increases by at least 35°, preferably by at least 45°. Because the backrest of the seat unit is fixedly attached to the backrest bracket 21, the angle of the backrest, especially the front side of the backrest, relative to the horizontal reference plane also increases by at least 35°, preferably by at least 45°.

[0075] As previously described, the fixing plate 12 of the mechanical extension device 1 is fixedly mounted on the armrest frame 60. The seat frame 10 is movably connected to the fixing plate 12 via a linkage assembly. This linkage assembly comprises a main linkage assembly and a secondary linkage assembly. The main linkage assembly includes at least a front swing link 13, a rear swing link 14, and an intermediate link 15; the secondary linkage assembly includes at least a secondary front swing link 17, a secondary rear swing link 18, a secondary front linkage link 17a, a secondary rear linkage link 18a, a secondary intermediate link 19a, and a follower link 19b. The main linkage assembly is used to move the seat frame 10 forward and backward relative to the intermediate link 15 during the transition between the sitting position and the TV position, while the intermediate link 15 remains substantially stationary relative to the armrest. The secondary linkage assembly is used to move the seat frame, along with the main linkage assembly, forward and backward relative to the armrest during the transition between the TV position and the reclining position.

[0076] The upper ends of the front swing link 13 and the rear swing link 14 are each pivotally connected to the seat frame 10. The lower end of the front swing link 13 is pivotally connected to the front portion of the intermediate link 15 at a sixth pivot point P6. The lower end of the rear swing link 14 is pivotally connected to the rear portion of the intermediate link 15 at a seventh pivot point P7. Furthermore, a seat frame linkage link 16 is pivotally connected between the front end of the intermediate link 15 and the seat frame 10. Thus, the seat frame 10, the front swing link 13, the rear swing link 14, and the intermediate link 15 form a four-bar linkage. When the leg extension device 3 extends from the sitting position under the action of the linear electric drive, it drives the seat frame 10 forward, thereby causing the front swing link 13 and the rear swing link 14 to tilt forward about their respective pivot points on the intermediate link 15.

[0077] The upper end of the secondary front linkage rod 17a is pivotally connected to the upper end of the secondary front swing rod 17, and the lower end is pivotally connected to the front part of the intermediate link 15; the lower end of the secondary rear linkage rod 18a is pivotally connected to the rear end of the intermediate link 15 at the eighth pivot point P8, and the upper end is pivotally connected to the middle part of the secondary rear swing rod 18 at the ninth pivot point P9, wherein the seventh pivot point P7 is located between the sixth pivot point P6 and the eighth pivot point P8.

[0078] The rear end of the secondary intermediate link 19a is pivotally connected to the middle portion of the secondary rear linkage link 18a at a tenth pivot point P10, and the front end of the secondary intermediate link 19a is pivotally connected to the top end of the secondary front swing link 17. In addition, a follower link 19b is provided between the secondary intermediate link 19a and the secondary rear swing link 18, wherein the front end of the follower link 19b is pivotally connected to the middle portion of the secondary intermediate link 19a, and the rear end of the follower link 19b is pivotally connected to the top end of the secondary rear swing link 18 at an eleventh pivot point P11.

[0079] The lower end of the auxiliary front swing link 17 is pivotally connected to the front end of the fixed plate 12, and the lower end of the auxiliary rear swing link 18 is pivotally connected to the fixed plate 12 at a twelfth pivot point P12.

[0080] Thus, the intermediate link 15 is suspended and supported on the fixing plate 12 so as to be movable forward and backward via the secondary link assembly.

[0081] When the seat frame linkage rod 16 is driven to move forward to the extreme position, that is, to the TV posture position, if the linear electric drive device continues to act in the same direction, the intermediate link 15 and the seat frame 10 will move forward together, thereby driving the auxiliary front swing link 17 and the auxiliary rear swing link 18 to pivot and tilt forward about the pivot points of their lower ends and the fixed plate 12.

[0082] In order to make the mechanical extension device 1 change smoothly between different postures and make the seat frame rise more significantly in the lying position, the size ratios of some components are optimized.

[0083] In particular, as shown in Figure 11, the seventh pivot point P7 of the intermediate link 15 is located between the sixth pivot point P6 and the eighth pivot point P8, wherein the distance between the sixth pivot point P6 and the eighth pivot point P8 is set to L1, and the distance between the eighth pivot point P8 and the seventh pivot point P7 is set to L2, L2 / L1≤0.35.

[0084] The tenth pivot point P10 of the secondary rear linkage 18a is located between the eighth pivot point P8 and the ninth pivot point P9, wherein the distance between the eighth pivot point P8 and the tenth pivot point P10 is set to L3, and the distance between the ninth pivot point P9 and the tenth pivot point P10 is set to L4, L4 / L3≤1.

[0085] In particular, as shown in Figure 12, the ninth pivot point P9 of the secondary rear swing link 18 is located between the eleventh pivot point P11 and the twelfth pivot point P12, wherein the distance between the twelfth pivot point P12 and the ninth pivot point P9 is set to L5, and the distance between the eleventh pivot point P11 and the ninth pivot point P9 is set to L6, L6 / L5≤1.

[0086] In this way, the jamming of the seat unit during posture change is overcome, and the front end of the seat frame and the seat part attached thereto are raised at a larger angle in the lying position, thereby prompting the leg extension device 3 to extend further upward and forward, thereby reaching a zero gravity state, that is, in the lying position, the highest point of the leg extension device 3 is higher than the highest point of the backrest.

[0087] The leg extension device 3 includes a first link 311, a second link 312, a third link 321, and a fourth link 322, as well as a connecting end surface 331 and a terminal end surface 332 for attaching the footrest 631. The second link 312 is provided with a retaining groove 3120. The fourth link 322 includes a retaining pin 3220. The first link 311 and the fourth link 322 are rotationally connected, while the second link 312 and the third link 321 are rotationally connected. The first link 311 and the second link 312 are both rotationally mounted to the seat frame 10, with the pivot point between the first link 311 and the seat frame 10 located behind the pivot point between the second link 312 and the seat frame 10. The footrest 631 is rotationally connected to the third link 321 and the fourth link 322 via the connecting end surface 331 and the terminal end surface 332. When the leg extension device 3 is unfolded, that is, in the TV position shown in FIG. 6 and the lying position shown in FIG. 7 , the second link 312 protrudes further forward than the first link 311 .

[0088] The illustrated mechanical extension device 1 also includes a linear electric actuator 4, comprising a motor head 41 and a motor push rod 42 that is retractable relative to the motor head 41. The motor head 41 is fixedly mounted relative to the armrest portion. For example, the motor head 41 is pivotally connected to a motor head bracket 41a, which is fixedly mounted to a fixed crossbeam 52. The motor head bracket 41a does not move in the fore-aft direction during the transition of the seat unit from a sitting position to a reclining position, but is instead pivotable about an axis transverse to the fore-aft direction. The motor push rod 42 acts on a front drive tube 44 that is laterally connected between the second connecting rods 312 of the leg extension device 3. Of course, in an embodiment not shown, the positions of the motor head 41 and the motor push rod 42 can also be reversed. The motor push rod 42 is attached to the front drive tube 44 via a motor bracket 43, wherein the motor push rod 42 is pivotally connected to the motor bracket 43, and the motor bracket 43 is fixedly connected to the front drive tube 44.

[0089] If the seat unit is to be moved from the sitting position shown in Figures 2 and 5 to the TV position shown in Figures 3 and 6, the mechanical extension mechanism 1 begins to extend under the action of the linear electric actuator 4. The motor push rod 42 extends relative to the motor head 41, pushing the second link 312 of the leg extension mechanism 3 forward. This in turn drives the seat frame 10 forward, tilting the front and rear swing arms 13 and 14 forward, thereby achieving the TV position shown in Figure 3. During this process, the entire seat frame 10 moves forward, causing the backrest link 22 shown in Figures 2 and 3 to pivot rearward about the second pivot point P2 at its lower end, i.e., rotate clockwise in the figures. To this end, a first stopper 101 is provided on the seat frame 10, located behind the backrest link 22. This supports the backrest link 22 from its rear side, preventing it from rocking in the sitting position and maintaining stable support for the backrest bracket 21. In this case, the backrest bracket 21, the backrest connecting rod 22, the crank member 23 and the seat frame 10 with the seat frame extension 11 move forward together with their relative positions remaining substantially unchanged, thereby driving the fixed plate connecting rod 24 to rotate forward around the pivot point between its lower end and the fixed plate 12.

[0090] During the process of the mechanical extension device changing from the sitting position shown in Figures 2 and 5 to the TV position shown in Figures 3 and 6, the backrest bracket 21 moves forward as a whole due to the forward movement of the seat frame 10. The first pivot point P1 of the backrest bracket 21 and the backrest link 22 has a forward movement trajectory, and the rearmost end point of the backrest bracket 21 has a forward movement component.

[0091] If the seat unit is to be moved from the TV posture position shown in Figures 3 and 6 to the reclining position shown in Figures 4 and 7, the motor push rod 42 continues to extend relative to the motor head 41, driving the seat frame 10 forward via the leg extender 3. The front swing link 13 and rear swing link 14 tilt forward to their limit positions. The intermediate link 15, along with the seat frame 10, moves forward and simultaneously lifts upward, thereby causing the auxiliary front swing link 17 and auxiliary rear swing link 18 to pivot and tilt forward about the pivot points between their lower ends and the fixed plate 12. Furthermore, as shown in Figure 4, the crank member 23 rotates counterclockwise about the fifth pivot point P5 between its lower end and the fixed plate link 24, tilting toward the leg extender. This reduces the height difference between its upper end and the fourth pivot point P4 in the middle, thereby pushing the entire backrest bracket 21 forward and tilting the upper portion of the backrest bracket 21 further rearward, reducing the angle of the backrest link 22 relative to the seat frame 10. This achieves the reclining position shown in Figure 4. During this process, on the one hand, the seat frame 10 itself moves forward, and on the other hand, the backrest bracket 21 also moves forward relative to the seat frame 10 by virtue of the linkage action of the backrest connecting rod 22 and the crank member 23. Therefore, the backrest bracket 21 as a whole has a forward movement trajectory, wherein the rearmost end point of the backrest bracket 21 and the top end of the backrest bracket 21 both move significantly forward.

[0092] Figure 13 schematically illustrates the transitions of the mechanical extender according to the present application between a sitting position, a TV position, and a reclining position. For greater clarity, the vertical plane at the top of the backrest bracket 21 in the sitting position is defined as a first horizontal reference plane E1. During these transitions, the first reference plane E1 remains fixed relative to the floor-mounted armrest of the seat unit. The upper portion of Figure 13 illustrates the mechanical extender in the sitting position, the middle portion in the TV position, and the lower portion in the reclining position.

[0093] In the sitting position, the backrest, attached to the backrest bracket 21 by means of the backrest frame 61, is generally oriented vertically, with the leg extension retracted. In the TV position, the backrest is not significantly tilted, and the leg extension extends forward and upward. In the reclining position, the backrest frame 61 moves forward, driven by the backrest link 22. The lower end of the backrest frame 61 moves forward at a particularly large extent, with its lower edge raised upward and forward, occupying a larger horizontal space in the seat portion, thereby providing sufficient support for the user's waist. Furthermore, in the reclining position, the leg extension rises further upward, with its highest point exceeding the highest point of the backrest in the height direction, thereby achieving a zero-gravity posture. As shown in Figure 10, the highest point of the leg extension 3 is higher than the highest point of the backrest bracket 21, with a height difference H of at least 300 mm.

[0094] The above description fully discloses the specific embodiments of this application. It should be noted that any changes made by those skilled in the art to the specific embodiments of this application do not depart from the scope of the claims of this application. Accordingly, the scope of the claims of this application is not limited to the aforementioned specific embodiments.

Claims

1. A mechanical extension device (1) for a movable chair unit, the mechanical extension device (1) being capable of being changed between a sitting position, a TV position and a lying position, the mechanical extension device (1) comprising: Fixed plate (12); A seat frame (10) movable forward and backward relative to the fixed plate (12) for attaching a seat portion of a movable chair; a backrest assembly (2) connected to the rear portion of the seat frame (10), the backrest assembly (2) comprising a backrest bracket (21), a backrest connecting rod (22) and a crank member (23), wherein the backrest bracket (21) is used to attach the backrest of the seat unit, and the backrest bracket (21) is pivotally connected to the seat frame by means of the backrest connecting rod (22) and the crank member (23), so that during the transformation of the mechanical extension device (1) from the sitting position to the lying position, the rearmost end of the backrest bracket (21) has a tendency to move forward; and a leg extension device (3) connected to the front of the seat frame (10), In the lying position, the leg stretching device (3) stretches forward and upward, and the highest point of the leg stretching device (3) is at least 300 mm higher than the highest point of the backrest support (21).

2. The mechanical stretching device according to claim 1, wherein: In the lying position, the highest point of the leg extension device (3) is at least 370 mm higher than the highest point of the backrest support (21).

3. The mechanical stretching device (1) according to claim 1, wherein: The backrest link (22) includes a first pivot point (P1) located at its upper end and a second pivot point (P2) located at its lower end, wherein the backrest link (22) is pivotally connected to the front end of the backrest bracket (21) at the first pivot point (P1) and is pivotally connected to the seat frame (10) at the second pivot point (P2), wherein, in the sitting position, a line connecting the first pivot point (P1) and the second pivot point (P2) forms a first angle (α) with respect to the upper surface of the seat frame (10) that is open toward the leg extension device (3), and in the sitting position, the first angle (α) is greater than 90°.

4. The mechanical stretching device according to claim 3, wherein: The first angle (α) is 95° to 130° in the sitting position.

5. The mechanical stretching device (1) according to claim 1, wherein: The front side of the backrest bracket (21) forms a second angle (β) with the ground, which is open toward the leg extension device (3). The second angle (β) increases by at least 35 degrees in the lying position compared to the sitting position.

6. The mechanical stretching device (1) according to claim 5, wherein: The second angle (β) is increased by at least 45° in the lying position compared to the sitting position.

7. The mechanical stretching device (1) according to claim 1, wherein: The crank member (23) includes three pivot points, namely a third pivot point (P3), a fourth pivot point (P4) and a fifth pivot point (P5), wherein the third pivot point (P3) and the fifth pivot point (P5) are respectively located on the upper end and the lower end of the crank member (23), and the fourth pivot point (P4) is located between the third pivot point (P3) and the fifth pivot point (P5), wherein the crank member (23) is pivotally connected to the rear end of the backrest bracket (21) at the third pivot point (P3), pivotally connected to the seat frame (10) at the fourth pivot point (P4), and at least indirectly coupled to the fixed plate (12) at the fifth pivot point (P5).

8. The mechanical stretching device (1) according to claim 1, wherein: The seat frame (10) is attached to the fixed plate (12) in a manner that allows it to move forward and backward via a main linkage assembly and a secondary linkage assembly, wherein the seat frame (10) is pivotally connected to the main linkage assembly, and the secondary linkage assembly is pivotally connected to the fixed plate (12).

9. The mechanical stretching device (1) according to claim 8, wherein The main linkage assembly comprises a front swinging rod (13), a rear swinging rod (14) and an intermediate linkage (15) pivotally connected to the secondary linkage assembly. When the mechanical stretching device (1) is transformed from a sitting position to a TV position, the rear end of the seat frame is driven by the main linkage assembly to move downward and forward relative to the intermediate linkage, wherein the intermediate linkage has no relative displacement relative to the fixed plate. When the mechanical stretching device is transformed from a TV position to a lying position, the seat frame is driven by the secondary linkage assembly to move forward and upward relative to the fixed plate together with the main linkage assembly.

10. The mechanical stretching device (1) according to claim 9, wherein The upper ends of the front swing link (13) and the rear swing link (14) are pivotally connected to the seat frame (10), the lower end of the front swing link (13) is pivotally connected to the intermediate link (15) at a sixth pivot point (P6), and the lower end of the rear swing link (14) is pivotally connected to the intermediate link (15) at a seventh pivot point (P7).

11. The mechanical stretching device (1) according to claim 10, wherein: The secondary linkage assembly comprises a secondary front swing rod (17), a secondary rear swing rod (18), a secondary front linkage rod (17a), a secondary rear linkage rod (18a), a secondary intermediate linkage rod (19a) and a follower linkage rod (19b), wherein the lower end of the secondary rear linkage rod (18a) is pivotally connected to the rear end of the intermediate linkage rod (15) at an eighth pivot point (P8), the top end of the secondary rear linkage rod (18a) is pivotally connected to the middle part of the secondary rear swing rod (18) at a ninth pivot point (P9), and the rear end of the secondary intermediate linkage rod (19a) is pivotally connected to the middle part of the secondary rear linkage rod (18a) at a tenth pivot point (P10).

12. The mechanical stretching device according to claim 11, wherein: The seventh pivot point (P7) is located between the sixth pivot point (P6) and the eighth pivot point (P8), wherein the ratio of the distance between the eighth pivot point (P8) and the seventh pivot point (P7) to the distance between the sixth pivot point (P6) and the eighth pivot point (P8) is not greater than 0.

35.

13. The mechanical stretching device according to claim 11, wherein: The tenth pivot point (P10) is located between the eighth pivot point (P8) and the ninth pivot point (P9), wherein the ratio of the distance between the ninth pivot point (P9) and the tenth pivot point (P10) to the distance between the eighth pivot point (P8) and the tenth pivot point (P10) is not greater than 1.

14. The mechanical stretching device (1) according to claim 11, wherein The top end of the auxiliary front swing link (17) is pivotally connected to the front end of the auxiliary intermediate link (19a), the lower end of the auxiliary front swing link (17) is pivotally connected to the fixed plate (12), the top end of the auxiliary rear swing link (18) is pivotally connected to the rear end of the follower link (19b) at an eleventh pivot point (P11), and the lower end of the auxiliary rear swing link (18) is pivotally connected to the fixed plate (12) at a twelfth pivot point (P12).

15. Mechanical stretching device (1) according to claim 14, wherein The ninth pivot point (P9) is located between the eleventh pivot point (P11) and the twelfth pivot point (P12), wherein the ratio of the distance between the eleventh pivot point (P11) and the ninth pivot point (P9) to the distance between the twelfth pivot point (P12) and the ninth pivot point (P9) is not greater than 1.

16. A movable chair unit comprising a mechanical extension device (1), an armrest portion (602) attached to the mechanical extension device (1), a backrest, and a seat portion, wherein: The mechanical extension device (1) is capable of changing the seat unit between a sitting position, a TV position and a lying position, wherein: The mechanical stretching device (1) comprises: Fixed plate (12); A seat frame (10) movable forward and backward relative to the fixing plate (12) for attaching a seat portion; a backrest assembly (2) connected to the rear portion of the seat frame (10), the backrest assembly (2) comprising a backrest bracket (21), a backrest connecting rod (22) and a crank member (23), wherein the backrest bracket (21) is used to attach a backrest, and the backrest bracket (21) is pivotally connected to the seat frame by means of the backrest connecting rod (22) and the crank member (23), so that during the transformation of the mechanical extension device (1) from a sitting position to a lying position, the rearmost end of the backrest bracket (21) has a tendency to move forward; and a leg extension device (3) connected to the front of the seat frame (10), In the lying position, the leg stretching device (3) stretches forward and upward, and the highest point of the leg stretching device (3) is at least 300 mm higher than the highest point of the backrest support (21).

17. The seating unit of claim 16, wherein: In the lying position, the highest point of the leg extension device (3) is at least 370 mm higher than the highest point of the backrest support (21).

18. The seating unit of claim 16, wherein: The backrest link (22) includes a first pivot point (P1) located at its upper end and a second pivot point (P2) located at its lower end, wherein the backrest link (22) is pivotally connected to the front end of the backrest bracket (21) at the first pivot point (P1) and is pivotally connected to the seat frame (10) at the second pivot point (P2), wherein, in the sitting position, a line connecting the first pivot point (P1) and the second pivot point (P2) forms a first angle (α) with respect to the upper surface of the seat frame (10) that is open toward the leg extension device (3), and in the sitting position, the first angle (α) is greater than 90°.

19. The seating unit of claim 18, wherein: The first angle (α) is 95° to 130° in the sitting position.

20. The seating unit of claim 16, wherein: The front side of the backrest bracket (21) forms a second angle (β) with the ground, which is open toward the leg extension device (3). The second angle (β) increases by at least 35 degrees in the lying position compared to the sitting position.

21. The seating unit of claim 20, wherein: The second angle (β) is increased by at least 45° in the lying position compared to the sitting position.

22. The seating unit of claim 16, wherein: The crank member (23) includes three pivot points, namely a third pivot point (P3), a fourth pivot point (P4) and a fifth pivot point (P5), wherein the third pivot point (P3) and the fifth pivot point (P5) are respectively located on the upper end and the lower end of the crank member (23), and the fourth pivot point (P4) is located between the third pivot point (P3) and the fifth pivot point (P5), wherein the crank member (23) is pivotally connected to the rear end of the backrest bracket (21) at the third pivot point (P3), pivotally connected to the seat frame (10) at the fourth pivot point (P4), and at least indirectly coupled to the fixed plate (12) at the fifth pivot point (P5).

23. The seating unit of claim 16, wherein: The seat frame (10) is attached to the fixed plate (12) in a manner that allows it to move forward and backward via a main linkage assembly and a secondary linkage assembly, wherein the seat frame (10) is pivotally connected to the main linkage assembly, and the secondary linkage assembly is pivotally connected to the fixed plate (12).

24. The seating unit of claim 23, wherein: The main linkage assembly comprises a front swinging rod (13), a rear swinging rod (14) and an intermediate linkage (15) pivotally connected to the secondary linkage assembly. When the mechanical stretching device (1) is transformed from a sitting position to a TV position, the rear end of the seat frame is driven by the main linkage assembly to move downward and forward relative to the intermediate linkage, wherein the intermediate linkage has no relative displacement relative to the fixed plate. When the mechanical stretching device is transformed from a TV position to a lying position, the seat frame is driven by the secondary linkage assembly to move forward and upward relative to the fixed plate together with the main linkage assembly.

25. The seating unit of claim 24, wherein: The upper ends of the front swing link (13) and the rear swing link (14) are pivotally connected to the seat frame (10), the lower end of the front swing link (13) is pivotally connected to the intermediate link (15) at a sixth pivot point (P6), and the lower end of the rear swing link (14) is pivotally connected to the intermediate link (15) at a seventh pivot point (P7).

26. The seating unit of claim 25, wherein: The secondary linkage assembly comprises a secondary front swing rod (17), a secondary rear swing rod (18), a secondary front linkage rod (17a), a secondary rear linkage rod (18a), a secondary intermediate linkage rod (19a) and a follower linkage rod (19b), wherein the lower end of the secondary rear linkage rod (18a) is pivotally connected to the rear end of the intermediate linkage rod (15) at an eighth pivot point (P8), the top end of the secondary rear linkage rod (18a) is pivotally connected to the middle part of the secondary rear swing rod (18) at a ninth pivot point (P9), and the rear end of the secondary intermediate linkage rod (19a) is pivotally connected to the middle part of the secondary rear linkage rod (18a) at a tenth pivot point (P10).

27. The seating unit of claim 26, wherein: The seventh pivot point (P7) is located between the sixth pivot point (P6) and the eighth pivot point (P8), wherein the ratio of the distance between the eighth pivot point (P8) and the seventh pivot point (P7) to the distance between the sixth pivot point (P6) and the eighth pivot point (P8) is not greater than 0.

35.

28. The seating unit of claim 26, wherein: The tenth pivot point (P10) is located between the eighth pivot point (P8) and the ninth pivot point (P9), wherein the ratio of the distance between the ninth pivot point (P9) and the tenth pivot point (P10) to the distance between the eighth pivot point (P8) and the tenth pivot point (P10) is not greater than 1.

29. The seating unit of claim 26, wherein: The top end of the auxiliary front swing link (17) is pivotally connected to the front end of the auxiliary intermediate link (19a), the lower end of the auxiliary front swing link (17) is pivotally connected to the fixed plate (12), the top end of the auxiliary rear swing link (18) is pivotally connected to the rear end of the follower link (19b) at an eleventh pivot point (P11), and the lower end of the auxiliary rear swing link (18) is pivotally connected to the fixed plate (12) at a twelfth pivot point (P12).

30. The seating unit of claim 29, wherein: The ninth pivot point (P9) is located between the eleventh pivot point (P11) and the twelfth pivot point (P12), wherein the ratio of the distance between the eleventh pivot point (P11) and the ninth pivot point (P9) to the distance between the twelfth pivot point (P12) and the ninth pivot point (P9) is not greater than 1.

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