Adjustable seat unit and mechanical extension apparatus therefor

Abstract

A mechanical extension apparatus for an adjustable seat unit, comprising: a base unit (10) fixedly arranged relative to the ground, wherein the height of the lowest point of the base unit (10) relative to the ground is 5-15 cm; a seat frame (12) slidable relative to the base unit (10); a leg extension apparatus (3); and an electric drive unit (4) at least comprising a motor head (41) fixedly connected to the base unit (10), a motor slide rail (42) fixedly arranged on the base unit (10) and below the seat frame (12), a motor slide block (43) slidable along the motor slide rail (42), and motor connecting rods (44) connected between the motor slide block (43) and the leg extension apparatus (3) or the seat frame (12), wherein the electric drive unit (4) can drive the seat frame (12) to switch between an initial state and a slide-out state, when the seat frame (12) switches from the initial state to the slide-out state, front portions of seat frame longitudinal beams (121) are lifted upward to a greater extent than the rear portions thereof, and in the initial state, the height of the front end of the seat frame (12) relative to the ground is 25-35 cm.

Description

Movable seat unit and its mechanical extension device Technical Field

[0001] This application relates to a mechanical extension device for a movable seat unit and a movable seat unit including said mechanical extension device. Background Technology

[0002] Various types of movable seating are known in the prior art, such as sofas or chairs with multi-position conversion functions. As people's living standards improve, the demand for comfort in sofas and chairs is also increasing. In known designs, movable seating units typically have a mechanical extension device, allowing them to switch between sitting, relaxing, and reclining positions. When the seating unit changes from a sitting position to a reclining position, the footrest extends forward, and the angle between the backrest and the seat changes slightly. When the seating unit changes from a reclining position to a reclining position, the footrest extends further forward and upward compared to the reclining position, and the backrest reclines significantly. In existing movable seating designs, the footrest is often raised as high as possible to achieve a "zero-gravity" posture in the reclining position, making it significantly higher than the highest point of the backrest support. However, in existing designs, complex mechanical connection mechanisms are often used to achieve this goal, such as numerous linkages and multi-stage lifting structures. This not only brings the disadvantages of complex structure and complicated installation process, but also occupies a lot of space under the seat unit, so that the seat frame must be raised significantly to make enough space to allow cleaning under the seat unit; in addition, due to the complex connection structure, there is also the risk of functional failure, especially during the seat posture change process, the rear of the seat frame sinks and causes interference with the electric drive unit. Summary of the Invention

[0003] The technical problem to be solved by this application is to provide a movable seat unit with a simpler structure, smaller required placement space, and better comfort.

[0004] To address the aforementioned technical problems, this application provides a mechanical extension device for a movable seat unit. The mechanical extension device includes: a base unit fixedly disposed relative to the ground, which movably supports the mechanical extension device above the ground, wherein the lowest point of the base unit is 5-15 cm above the ground; a seat frame slidable relative to the base unit, comprising a pair of seat frame longitudinal beams extending along the front-rear direction of the seat unit; a leg extension device pivotally connected to the front of the seat frame; and an electric drive unit, comprising at least a motor head fixedly connected to the base unit and a leg extension device on the seat frame. The base unit has a motor slide rail fixedly arranged below, a motor slider that can slide along the motor slide rail, and a motor connecting rod connected between the motor slider and the leg extension device or the seat frame. The seat frame can be driven by the electric drive unit to change between an initial state in which it is not sliding relative to the base unit and a sliding out state in which it slides forward relative to the base unit. When the seat frame changes from the initial state to the sliding out state, the front part of the seat frame longitudinal beam is raised to a greater extent than the rear part. In the initial state, the front end of the seat frame is 25-35 cm above the ground.

[0005] For ease of cleaning, the bottom of the movable seat should be "suspended" above the ground. In the design according to this application, the motor rail of the electric drive unit is fixedly arranged below the seat frame relative to the base unit. Simultaneously, the sliding of the seat frame relative to the base unit follows an upward trajectory; that is, during the transition of the seat frame from its initial state to its slid-out state, the front of the seat frame's longitudinal beam rises more significantly than its rear, ensuring that the rear of the seat frame does not descend during its entire forward sliding process. This avoids interference between the electric drive unit and the seat frame during posture changes. This allows for a suitable reduction in the height of the front end of the seat frame without needing to increase the seat frame height to obtain sufficient space under the seat, as is done in the prior art. Therefore, even when the seat unit, especially its base unit and seat frame, are compact in the height direction, sufficient space is ensured under the seat unit for cleaning equipment, such as a robotic vacuum cleaner, to perform cleaning operations.

[0006] In some embodiments, the sliding of the seat frame relative to the base unit is achieved by a cooperating sliding groove and roller.

[0007] Of course, in some implementations, the sliding of the seat frame relative to the base unit can also be achieved by other means, such as mutually cooperating sliders and slide rails installed on the seat frame and the base unit respectively, or pins and guide grooves, etc.

[0008] In some embodiments, the base unit includes a slide member with a first slide section and a second slide section, wherein the first slide section is arranged in front of the second slide section and the first slide section is inclined upward to a greater extent relative to the horizontal plane than the second slide section; the seat frame includes at least one roller.

[0009] In some embodiments, the second chute section extends parallel to the horizontal plane. In this case, the first chute section extends obliquely upward relative to the horizontal plane.

[0010] In some embodiments, the first chute section and the second chute section may both extend upwards at an angle relative to the horizontal plane, wherein the first chute section has a greater angle of inclination than the second chute section.

[0011] In some embodiments, the first chute section extends in a straight line. Alternatively, the first chute section extends in a curved line.

[0012] In some embodiments, the first and second chute sections are constructed as a continuous chute. In some embodiments, the seat frame longitudinal beam includes at least a first roller and a second roller, wherein, during the sliding of the seat frame relative to the base unit, the first roller rolls at least in the first chute section, and the second roller rolls at least in the second chute section.

[0013] In some embodiments, the first slide section and the second slide section are each constructed as independent slides. In some embodiments, the seat frame longitudinal beam includes at least a first roller and a second roller, the first roller being rotatably embedded in the first slide section, and the second roller being rotatably embedded in the second slide section.

[0014] Compared to the initial state of the seat frame, after the seat frame slides forward relative to the base unit, i.e., in the slid-out state, the front end of the seat frame longitudinal beam is positioned in the first groove section with a greater height via the first roller, while the rear end of the seat frame longitudinal beam is positioned in the second groove section with a smaller height via the second roller, or is also positioned in the first groove section, but the height of the second roller is lower than that of the first roller. This ensures that after the seat frame slides forward relative to the base unit, the front of the seat frame tilts upward more dramatically than its rear.

[0015] According to this application, the mechanical extension device includes a backrest unit pivotally connected between the base unit and the seat frame, and includes a backrest bracket, a backrest link, and a crank. The backrest bracket is used to attach the backrest of the seat unit. The backrest link includes a first pivot point at its upper end and a second pivot point at its lower end. The backrest link is pivotally connected to the front end of the backrest bracket at the first pivot point and to the seat frame at the second pivot point. The upper end of the crank is pivotally connected to the rear end of the backrest bracket at a third pivot point, and the lower end of the crank is pivotally connected to the base unit at a fourth pivot point.

[0016] In some embodiments, once the seat frame slides forward relative to the base unit, the angle between the line connecting the first pivot point and the second pivot point and the longitudinal beam of the seat frame decreases.

[0017] Because the backrest unit is pivotally connected between the seat frame and the base unit, and the seat frame and base unit are slidably connected, the forward and backward sliding of the seat frame relative to the base unit will not cause excessive height changes in the overall height of the seat frame. Unlike existing technologies, the seat frame of this application only produces a relatively gentle height difference during forward sliding. This means that the backrest link does not maintain a relatively identical relative position with the seat frame when it moves with the seat frame. Instead, under the pressure of the crank's rotation, the backrest link moves forward with its upper end and approaches the longitudinal beam of the seat frame, reducing the angle between the line connecting the first and second pivot points and the longitudinal beam of the seat frame. This, on the one hand, drives the backrest support to move forward as a whole, achieving a completely "zero-wall" arrangement of the seat unit; on the other hand, it allows the backrest unit to approach the seat frame more closely during the forward movement of the seat frame, achieving a "zero-back-rubbing" design. Furthermore, since the forward sliding of the seat frame relative to the base unit is along a non-linear trajectory, the front part of the seat frame longitudinal beam is raised to a greater extent than the rear part, which can easily raise the leg extension device further and help provide users with a "zero gravity" experience.

[0018] In some embodiments, the highest point of the backrest support tends to move downward and forward by sliding the seat frame forward relative to the base unit.

[0019] In some embodiments, the crank component further includes a fifth pivot point located between the third pivot point and the fourth pivot point, the crank component being pivotally connected to the rear of the seat frame at the fifth pivot point, wherein the fifth pivot point is located behind the second pivot point.

[0020] In some embodiments, the electric drive unit includes an electric actuator acting between the base unit and the leg extension device, by means of which the seat unit can sequentially change between a sitting position, a TV position, and a reclining position.

[0021] In some embodiments, the mechanical extension device includes a motor crossbeam extending laterally between the leg extension devices, wherein the motor head is connected to the base unit and the motor linkage is connected to the motor crossbeam, and the extension of the electric actuator causes the leg extension devices and the seat frame to move sequentially. The adjustment stroke achieved by the extension of the electric actuator is divided into two sequential stages: in the first stage, the leg extension devices extend forward relative to the seat frame; in the second stage, the seat frame slides forward relative to the base unit, and the backrest support tilts backward, reducing the angle between the line connecting the first pivot point and the second pivot point and the longitudinal beam of the seat frame.

[0022] In some embodiments, the mechanical extension device includes an electrically driven unit comprising a seat frame actuator acting between the base unit and the seat frame, and / or a leg actuator acting between the seat frame and the leg extension device. The electrically driven unit enables the mechanical extension device to switch between a sitting position, a TV position, and / or a reclining position. In some embodiments, the seat frame actuator and the leg actuator can be controlled independently. Adjustment of the seat frame actuator enables sliding of the seat frame relative to the base unit. Adjustment of the leg actuator enables extension and retraction of the leg extension device relative to the seat frame.

[0023] To address the aforementioned technical problem, this application also provides a movable seat unit that includes the aforementioned mechanical extension device.

[0024] The advantages described above for the mechanical extension device also apply to movable seat units with such a mechanical extension device. Attached Figure Description

[0025] The embodiments of this application are described in detail below with reference to the accompanying drawings.

[0026] Figure 1 schematically shows a perspective view of the mechanical extension device of the seat unit according to the present application;

[0027] Figure 2 schematically shows a partial perspective view of the mechanical extension device shown in Figure 1 from another angle, in a seated position;

[0028] Figure 3 schematically shows the TV position of the mechanical extension device shown in Figure 2;

[0029] Figure 4 schematically shows the lying position of the mechanical extension device shown in Figure 2 in a three-dimensional view;

[0030] Figure 5 shows the seated position of the mechanical extension device shown in Figure 1 in a side view;

[0031] Figure 6 schematically illustrates the TV position of the mechanical extension device shown in Figure 2 in a side view; and

[0032] Figure 7 schematically shows the lying position of the mechanical extension device shown in Figure 2 in a side view. Embodiments of the present invention

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] The term "one embodiment" or "implementation" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. In the description of this application, it should be understood that the terms "upper," "lower," "left," "right," "top," "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0035] Unless otherwise stated, the term "front-to-back direction" as used in this application refers to the direction of extension of the leg units of the furniture unit, especially the seat unit. Specifically, "front" refers to the direction toward the leg units, and "rear" refers to the direction toward the backrest unit. The term "left-right direction" or "lateral direction" refers to the direction of the furniture unit, especially the seat unit, in the horizontal direction that is perpendicular to the "front-to-back direction".

[0036] Figure 1 schematically shows a perspective view of the mechanical extension device of the 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 partial perspective view; Figures 5 to 7 show the mechanical extension device of the seat unit according to the present application in side view.

[0037] The mechanical extension device 1 includes a multi-link mechanism and is configured to allow the movable seat to change between a sitting position, a TV position, and a reclining position. However, this application is not limited to this. In other embodiments not shown, the movable seat may also change only between the folded position and the TV position or only between the folded position and the reclining position.

[0038] The mechanical extension device includes a base unit 10 fixed relative to the ground, a seat frame 12 slidable relative to the base unit 10, a backrest unit 2 pivotally connected to the rear of the seat frame 12, and a leg extension device 3 pivotally connected to the front of the seat frame 12.

[0039] In one embodiment, the mechanical extension device is constructed as a movable seat unit with a floor-standing iron frame. For this purpose, the base unit 10, as shown in Figures 1 to 7, includes two base longitudinal beams 101 extending in the front-rear direction of the seat unit, a front base crossbeam 102 and a rear base crossbeam 103 extending laterally between the two base longitudinal beams 101. The two base longitudinal beams 101, the front base crossbeam 102, and the rear base crossbeam 103 form a base frame, and four legs 104 extend downwards from the base unit 10 to "suspend" the mechanical extension device above the ground.

[0040] In an embodiment not shown, the mechanical extension device can also be configured as a seat unit with armrests on the ground. For this purpose, the base unit 10 can be fixedly attached to the inside of the armrest portion supported on the ground by means of two base longitudinal beams 101, thereby allowing the mechanical extension device to be "suspended" above the ground.

[0041] The seat frame 12 supports the seat portion of the movable seat unit. Specifically, as shown in Figure 2, the seat frame 12 comprises two seat frame longitudinal beams 121 along the front-rear direction of the seat unit, a front seat frame crossbeam 122 extending between the two longitudinal beams, and a rear seat frame crossbeam 123. Furthermore, the seat frame 12 includes an upwardly extending rear seat frame extension 124 fixedly disposed at its rear. This rear seat frame extension 124 can be integrally formed with the main body of the seat frame 12, or it can be fixedly connected to it as a separate component, for example, by welding, riveting, or other methods.

[0042] To allow the seat frame 12 to slide relative to the base unit 10, the base unit 10 further includes a sliding groove 11, particularly disposed on its base longitudinal beam 101. The sliding groove 11 comprises at least two groove sections extending at different angles relative to the horizontal plane: a first groove section 14a located at the front and a second groove section 14b located at the rear. The angle between the first groove section 14a and the horizontal plane is greater than the angle between the second groove section 14b and the horizontal plane. In other words, the first groove section 14a is inclined at a greater angle than the second groove section 14b. In the embodiments shown in Figures 1 to 7, the first groove section 14a and the second groove section 14b are constructed together as a continuous groove; however, in embodiments not shown, the first groove section 14a and the second groove section 14b may also be constructed as two separate grooves.

[0043] In some embodiments, the second chute section 14b extends substantially parallel to the horizontal plane, and the rear end of the first chute section 14a and the front end of the second chute section 14b transition to each other at an angle, wherein the first chute section 14a is significantly inclined upward relative to the horizontal plane.

[0044] The seat frame 12 has a generally L-shaped cross-section, comprising an upward-facing top surface 121a and a side surface 121b extending generally perpendicularly to the top surface 121a. The top surface 121a is configured to support the seat portion, and at least a first roller 14a and a second roller 14b are rotatably mounted on the side surface 121b. The first roller and the second roller are movably engaged in the grooves of the sliding member 11, thereby allowing the seat frame 12 to slide relative to the base unit 10.

[0045] The backrest unit 2 includes a backrest bracket 21, a backrest link 22, a crank 23, and a follower link 24, wherein the backrest unit 2 is pivotally connected between the seat frame 12 and the base unit 10.

[0046] The upper part of the backrest bracket 21 is fixedly connected to the backrest frame 20, and the backrest of the seat unit (not shown) is fixedly attached to the backrest frame 20. A backrest connecting rod 22 is connected between the front end of the backrest bracket 21 and the seat frame 12, and a crank 23 is connected between its rear end and the seat frame 12.

[0047] The backrest link 22 is constructed in a generally straight manner. Its upper end is pivotally connected to the front end of the backrest bracket 21 at the first pivot point P1, and its lower end is pivotally connected to the rear end of the seat frame 12 at the second pivot point P2.

[0048] The crank member 23 includes three pivot points: a third pivot point P3, a fourth pivot point P4, and a fifth pivot point P5. Specifically, as shown in Figure 3, the third pivot point P3 is located at the upper end of the crank member 23, the fourth pivot point P4 at its lower end, and the fifth pivot point P5 in its middle. The crank member 23 is pivotally connected to the rear end of the backrest support 21 at the third pivot point P3 via its upper end, and to the upper end of the follower link 24 at the fourth pivot point P4 via its lower end. The lower end of the follower link 24 is pivotally connected to the rear of the base unit 10. Furthermore, the crank member 23 is pivotally connected to the rearward extension 124 of the seat frame at the fifth pivot point P5 via its middle portion, thereby pivotally connecting to the rear of the seat frame 12. The fifth pivot point P5 is located further rearward than the second pivot point P2, meaning it is further away from the leg extension device 3 when viewed in the front-rear direction of the seat unit.

[0049] In the sitting position shown in Figure 5 and the TV position shown in Figure 6, the first pivot point P1 of the backrest link 22 is further back in the horizontal direction than the second pivot point P2, i.e., closer to the backrest. However, in the reclining position shown in Figure 7, the first pivot point P1 of the backrest link 22 is further forward in the horizontal direction than the second pivot point P2, i.e., closer to the leg extension device 3. This results in a significantly smaller angle α between the line connecting the first and second pivot points P1 and P2 of the backrest link 22 and the top surface 121 of the seat frame in the reclining position compared to the sitting and / or TV positions.

[0050] As shown in Figure 3, the leg extension device 3 includes a first link 31, a second link 32, a third link 33, and a fourth link 34, as well as a connecting end face 35 and an end face 36 for attaching a foot pedal (not specifically shown). The first link 31 is rotatably connected to the second link 32, and the third link 33 is rotatably connected to the fourth link 34. Both the first link 31 and the third link 33 are rotatably mounted on the seat frame 12, wherein the pivot point of the first link 31 and the seat frame 12 is located behind the pivot point of the third link 33 and the seat frame 12. The foot pedal is rotatably connected to the second link 32 and the fourth link 34 via the connecting end face 35 and the end face 36. When the leg extension device 3 is extended, i.e., in the TV position shown in Figure 6 and the lying position shown in Figure 7, the third link 33 extends further forward than the first link 31.

[0051] To enable the seat unit to change between different positions, the mechanical extension device also includes an electric drive unit 4.

[0052] In the embodiments shown in Figures 1 to 7, the electric drive unit 4 includes only one electric actuator acting between the base unit 10 and the leg extension device 3. The electric actuator is constructed as a linear actuator and includes a motor head 41, a motor rail 42 fixedly connected to the motor head 41, a motor slider 43 slidable relative to the motor head 41 along the motor rail 42, and a motor connecting rod 44. The motor head 41 is fixedly mounted at the rear of the base frame 10, for example, it can be mounted on the rear crossbeam 103 of the base frame 10, or it can be mounted on the seat unit back panel fixed relative to the base frame 10; the motor slide rail 42 is fixedly connected to the front crossbeam 102 and the rear crossbeam 103 of the base respectively, so as to be fixedly mounted below the seat frame 12 relative to the base unit 10; one end of the motor connecting rod 44 is hinged to the motor slider 43, and the other end is hinged to the motor crossbar 37, wherein the motor crossbar 37 extends laterally between the leg extension devices 3, for example, the motor crossbar 37 is fixedly attached to the third connecting rod 33 of the leg extension device 3 at both ends, thereby realizing the synchronous movement of the leg extension devices on the left and right sides of the seat unit.

[0053] In this embodiment, the electric drive unit 4 is designed to use a single electric actuator to cause the mechanical extension device of the seat unit to change sequentially between the sitting position, the TV position, and the reclining position.

[0054] The following description, using Figures 2 to 7, illustrates the changes in the mechanical extension device of the seat unit between the sitting, TV, and reclining positions. During the transition from the sitting to the reclining position, the adjustment of the electric drive unit 4 is divided into two sequential stages. In the first stage, the transition from the sitting to the TV position is achieved, and in the second stage, the transition from the TV position to the reclining position is achieved.

[0055] When the mechanical extension device is in the seated position shown in Figure 2 or Figure 5, the backrest frame 20 of the backrest unit 2, together with the backrest mounting member 21, stands upright. The line connecting the first pivot point P1 and the second pivot point P2 of the backrest link 22 forms an angle α with the top surface 121 of the seat frame 12. The leg extension device 3 is folded under the seat frame 12. The seat frame 12 is in an initial state without sliding relative to the base unit 10, wherein the first roller 14a and the second roller 14b of the seat frame 12 are located at the rear ends of the first slide section 11a and the second slide section 11b of the slide member 11, respectively. The height of the support leg 104 can be set as needed, for example, 5-15cm. Correspondingly, the height H1 of the front end of the seat frame 12 relative to the ground E0 can be selected as 28-35cm. Thus, the height H2 of the lowest point of the base unit 10, in this embodiment, for example, the lowest point of the slide member 11, relative to the ground E0, is allowed to be 5-15cm. Thus, while the height of the seat frame 12 is significantly reduced, sufficient space is still provided under the seat unit to facilitate the passage of the robot vacuum cleaner.

[0056] In some embodiments, the height of the support leg 104 can be set to about 14cm. In the sitting position, the height H1 of the front end of the seat frame relative to the ground E0 is 30-35cm, and the height H2 of the lowest point of the base unit 10, which in this embodiment is, for example, the lowest point of the slide 11, relative to the ground E0 is 10-15cm.

[0057] In some embodiments, the height of the support leg 104 can be set to about 6cm. In the sitting position, the height H1 of the front end of the seat frame relative to the ground E0 is 25-29cm, while the height H2 of the lowest point of the base unit 10, which in this embodiment is, for example, the lowest point of the slide 11, relative to the ground E0 is 5-9cm.

[0058] If the seat unit needs to change from the sitting position shown in Figure 2 or Figure 5 to the TV position shown in Figure 3 or Figure 6, the mechanical extension device begins to extend under the action of the electric drive unit 4. The electric drive unit 4 operates, causing the motor slider 43 to slide along the motor rail 42 away from the motor head 41, and pushes the motor crossbar 37 forward via the motor connecting rod 44, thereby unfolding the leg extension device 3. During this process, due to the weight of the user sitting on the seat, the seat frame 12 has not yet slid relative to the base unit 10. Therefore, the relative position between the backrest unit 2 and the seat frame 12 remains unchanged, and the included angle α in the TV position remains unchanged compared to the sitting position. Thus, the TV position shown in Figure 3 or Figure 6 is achieved. That is, in the first stage described above, only the leg extension device 3 unfolds, while the relative position between the backrest unit 2 and the seat frame 12 remains unchanged. The seat frame 12 does not move forward relative to the base unit 10; that is, the seat frame 12 maintains its initial state. Correspondingly, as in the seated position, the backrest support 21 and the ground E0 form a constant backrest angle β; this backrest angle β can be, for example, set as the angle between the line connecting the upper and lower fixed points of the backrest support 21 to the backrest frame 20 and the ground E0. Furthermore, as in the seated position, the seat frame 12 and the ground E0 form a constant seat frame angle γ; this seat frame angle γ can be, for example, set as shown in FIG. 6, as the angle between the top surface of the seat frame 12 and the horizontal line E1 parallel to the ground E0.

[0059] During the transition of the mechanical extension device from the TV position shown in Figure 3 or Figure 6 to the lying position shown in Figure 4 or Figure 7, the electric drive unit 4 continues to operate, causing the motor slider 43 to slide further away from the motor head 41 along the motor slide rail 42, thereby increasing the distance between the motor head 41 and the motor slider 43. When the leg extension device 3 extends forward to its maximum extent, the continued forward movement of the motor slider 43 causes the seat frame 12 to move forward relative to the base unit 10, thus transitioning to the slide-out state of the seat frame 12. During this process, the first roller 14a moves forward along the first slide section 11a until the front end of the first slide section 11a, and the second roller 14b similarly moves forward along the second slide section 11b until the front end of the second slide section 11b. Because the first slide section 11a is inclined upwards to a greater extent than the second slide section 11b relative to the horizontal plane, when the seat frame 12 slides forward, the front end of the seat frame 12 rises upwards at a greater angle than the rear end, and its rear end will at least not descend, thus effectively avoiding interference with the electric drive power supply 4. That is to say, during the process of changing from the TV position to the lying position, the seat frame 12 slides forward and rises upwards at the same time. In the lying position, the seat frame angle γ formed by the seat frame 12 and the ground E0 can be 13-26°.

[0060] Furthermore, as the seat frame 12 slides forward relative to the base unit 10, the crank 23, as shown in Figure 4 or Figure 7, rotates counterclockwise around its central fourth pivot point P4. The height difference between the upper end of the crank 23 and the third pivot point P3 of the backrest support 21 relative to the central fourth pivot point P4 decreases, thereby pushing the backrest support 21 forward as a whole. The upper part of the backrest support 21 tilts backward, and the angle α between the line connecting the first pivot point P1 and the second pivot point P2 of the backrest link 22 and the top surface 121 of the seat frame 12 decreases. This achieves the reclining position shown in Figure 4 or Figure 7. During this process, the seat frame 12 moves forward on one hand, and the backrest support 21 also moves forward relative to the seat frame 12 simultaneously with the linkage of the backrest connecting rod 22 and the crank 23. Therefore, the backrest support 21 has a forward trajectory as a whole, with the rearmost end and the top of the backrest support 21 moving significantly forward, thus achieving "zero wall contact". In summary, in the second stage, the seat frame 12 moves forward relative to the base unit 10, thereby driving the backrest unit 2 to move forward, and the backrest support 21 tilts backward. The leg extension device 3 extends further forward and upward with the seat frame 12, thus achieving a "zero gravity" posture. During the transition from the TV position to the reclining position, the backrest angle β between the backrest support 21 and the ground E0 can be reduced by 30-45°.

[0061] The corresponding reverse position change of the mechanical extension device of the seat unit is achieved by the retraction of the electric drive unit 4. The adjustment stroke is also divided into two stages implemented sequentially. In the first stage, the seat frame 12 slides backward relative to the base unit 10. In the second stage, the leg extension device 3 retracts backward relative to the seat frame 12. Further details are omitted here.

[0062] To ensure the sequential changes of the seat unit between various postures, a sequence element 5 is also provided. In this embodiment, the sequence element is constructed as a sequence spring acting between the base unit 10 and the seat frame 12, with one end connected to the inner side of the seat frame side surface 121b of the seat frame longitudinal beam 121, and the other end connected to the base unit 10. The sequence spring more reliably ensures the sequential changes of the seat unit between the sitting position, TV position, and reclining position, preventing disorder in the posture change order.

[0063] In a feasible embodiment not shown, the electric drive unit 4 may include not only one electric actuator, but at least two electric actuators, such as a seat frame actuator acting between the base unit 1 and the seat frame 12, and a leg actuator acting between the seat frame 12 and the leg extension device 3. For this purpose, for example, the motor head of the seat frame actuator can act on the rear crossbeam 103 of the base unit 10, with its motor rail fixedly connected between the front crossbeam 102 and the rear crossbeam 103, and its motor linkage acting on the rear crossbeam 123 or the front crossbeam 122 of the seat frame; the motor head of the leg actuator can act on the rear crossbeam 123 or the front crossbeam 122 of the seat frame, and its motor linkage acting on the motor crossbeam 37. The electric drive unit 4 enables the seat unit to switch between a sitting position, a TV position, and a reclining position. The seat frame actuator and the leg actuator can operate independently of each other, so that the forward and backward sliding of the seat frame 12 and the extension and retraction of the leg extension device 3 can be performed independently of each other.

[0064] It should be noted that any modifications made by those skilled in the art to the specific embodiments of this application do not depart from the scope of the claims. Accordingly, the scope of the claims is not limited to the foregoing specific embodiments.

Claims

1. A mechanical extension device for a movable seating unit, the mechanical extension device comprising: a base unit fixedly arranged relative to the ground, by means of which the mechanical extension device is movably supported above the ground, wherein the base unit has a lowest point which is 5-15 cm above the ground; a seat frame slidable relative to the base unit, which comprises a pair of seat frame longitudinal beams extending in a front-rear direction of the seating unit; a leg extension device pivotally connected to a front portion of the seat frame; and an electric drive unit comprising at least a motor head fixedly connected to the base unit, a motor rail fixedly arranged on the base unit below the seat frame, a motor slider slidable along the motor rail, and a motor link connected between the motor slider and the leg extension device or the seat frame, wherein the seat frame is transformable by means of the electric drive unit between an initial state in which the seat frame is not slidable relative to the base unit and a slid-out state in which the seat frame is slid forward relative to the base unit, wherein the front portion of the seat frame longitudinal beams is lifted upward to a greater extent than the rear portion when the seat frame is transformed from the initial state to the slid-out state, and wherein the front end of the seat frame is 25-35 cm above the ground in the initial state.

2. The mechanical stretching device of claim 1, wherein, The slidable movement of the seat frame relative to the base unit is realized by means of a cooperating slide and roller.

3. The mechanical stretching device of claim 2, wherein, The base unit comprises a slide having a first slide section and a second slide section, wherein the first slide section is arranged in front of the second slide section and the first slide section is inclined upward to a greater extent relative to the horizontal than the second slide section; the seat frame comprises at least one roller.

4. The mechanical stretching device of claim 3, wherein, The second slide section extends parallel to the horizontal.

5. The mechanical stretching device of claim 3, wherein, The first slide section extends linearly.

6. The mechanical stretching device of claim 3, wherein, The first slide section extends curvilinearly.

7. The mechanical stretching device of claim 3, wherein, The first slide section and the second slide section are configured as one continuous slide.

8. The mechanical stretching device of claim 7, wherein, The seat frame longitudinal beams comprise at least a first roller and a second roller, wherein the first roller rolls at least in the first slide section and the second roller rolls at least in the second slide section during the slidable movement of the seat frame relative to the base unit.

9. The mechanical stretching device of claim 3, wherein, The first slide section and the second slide section are respectively configured as independent slides.

10. The mechanical stretching device of claim 9, wherein, The seat frame longitudinal beams comprise at least a first roller and a second roller, the first roller is rollably embedded in the first slide section, and the second roller is rollably embedded in the second slide section.

11. The mechanical stretching device of claim 1, wherein, The mechanical extension device comprises a backrest unit, which is pivotally connected between the base unit and the seat frame, and comprises a backrest bracket, a backrest link and a curved lever, wherein the backrest bracket is used for attaching a backrest of the seat unit, the backrest link comprises a first pivot point at its upper end and a second pivot point at its lower end, wherein the backrest link is pivotally connected with a front end of the backrest bracket at the first pivot point and pivotally connected with the seat frame at the second pivot point, and an upper end of the curved lever is pivotally connected to a rear end of the backrest bracket at a third pivot point, and a lower end of the curved lever is pivotally connected to the base unit at a fourth pivot point.

12. The mechanical stretching device of claim 1, wherein, Once the seat frame slides forward relative to the base unit, an included angle between a line connecting the first pivot point and the second pivot point and the seat frame longitudinal beam is reduced.

13. The mechanical stretching device of claim 1, wherein, Through the forward sliding of the seat frame relative to the base unit, the highest point of the backrest bracket has a downward and forward moving tendency.

14. The mechanical stretching device of claim 1, wherein, The curved lever further comprises a fifth pivot point between the third pivot point and the fourth pivot point, and the curved lever is pivotally connected with a rear part of the seat frame at the fifth pivot point, wherein the fifth pivot point is located behind the second pivot point.

15. The mechanical stretching device of claim 11, wherein, The electric drive unit comprises an electric actuator acting between the base unit and the leg extension device, by means of which the seat unit can be sequentially transformed between the sitting position, the TV position and the lying position.

16. The mechanical stretching device of claim 15, wherein, The mechanical extension device comprises a motor crossbeam extending transversely between the leg extension devices, wherein the motor head is connected to the base unit, and the motor link is connected to the motor crossbeam, and through the extension of the electric actuator, the leg extension devices and the seat frame are sequentially moved in turn.

17. The mechanical stretching device of claim 15, wherein, The adjustment stroke achieved by the extension of the electric actuator is divided into two phases implemented in turn, in the first phase, the leg extension devices extend forward relative to the seat frame, and in the second phase, the seat frame slides forward relative to the base unit, and the backrest bracket is inclined backward, and an included angle between a line connecting the first pivot point and the second pivot point and the seat frame longitudinal beam is reduced.

18. The mechanical stretching device of claim 11, wherein, The mechanical extension device comprises an electric drive unit, which comprises a seat frame actuator acting between the base unit and the seat frame and / or a leg actuator acting between the seat frame and the leg extension device, by means of which the mechanical extension device can be transformed between the sitting position, the TV position and / or the lying position.

19. The mechanical stretching device of claim 17, wherein, The seat frame actuator and the leg actuator can be controlled independently of each other.

20. The mechanical stretching device of claim 19, wherein, The sliding of the seat frame relative to the base unit is achieved through the adjustment of the seat frame actuator.

21. The mechanical stretching device of claim 19, wherein, The extension of the leg extension devices relative to the seat frame is achieved through the adjustment of the leg actuator.

22. A movable seat unit comprising the mechanical extension device according to any one of the preceding claims 1 to 21.

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