Mechanical extension device for forward-leaning-preventing seating unit and movable seating unit

Abstract

The invention relates to a mechanical stretching device of an anti-forward-leaning seat unit and a movable seat unit, and the mechanical stretching device comprises a base unit which is fixedly arranged relative to the ground and comprises a base front cross beam and a base rear cross beam which are spaced from each other and extend in parallel, the mechanical stretching device is movably supported above the ground through the base unit; the seat frame can slide relative to the base unit; the leg stretching device is pivotally connected to the front part of the seat frame; an electric drive unit; the forward leaning prevention mechanism comprises an extension sliding rod extending in the front-back direction of the seat unit and an auxiliary connecting rod fixedly connected to the front end of the extension sliding rod and extending downwards, and a supporting wheel supported on the ground is arranged at the free end of the auxiliary connecting rod; when the leg stretching device moves in the front-back direction of the seat unit relative to the base unit, the forward leaning prevention mechanism synchronously moves in the front-back direction of the seat unit, and therefore the forward leaning prevention mechanism is converted between the initial position and the extending position.

Description

Technical Field

[0001] The invention relates to a mechanical extension device of an anti-tilting seat unit and a movable seat unit comprising the mechanical extension device. Background Art

[0002] In the prior art, there are many kinds of movable seats, such as sofas or seats with multi-position conversion functions. With the improvement of people's living standards, the comfort requirements for sofas and seats are also increasing. In the known design, the movable seat unit is usually equipped with a mechanical extension device, which can be transformed between a sitting position, a leisure position (or a TV position) and a lying position. When the seat unit is transformed from a sitting position to a TV position, the footrest of the seat unit extends forward, and the angle between the backrest and the seat portion changes slightly. When the seat unit is transformed from a TV position to a lying position, the footrest is further forward and upward than the TV position, and the backrest is significantly tilted back. In the existing design of movable seats, the footrest is often further raised as much as possible in pursuit of a "zero gravity" posture in the lying position, so that it is more obviously higher than the highest point of the backrest bracket. Due to the constant pursuit of the user experience of the leg extension device being lifted and stretched forward as much as possible, the center of gravity of the seat unit moves forward, thereby bringing the risk of the seat unit tipping forward as a whole. Especially in movable seats with floor-standing armrests, in order to leave space under the seat for the cleaning robot to pass through, a smaller base with a higher center of gravity is often used, which further increases the risk of the seat tipping forward. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a movable seat unit which has a safer and more stable structure and can reserve cleaning space while requiring a smaller placement space and providing better comfort.

[0004] In order to solve the above technical problems, the present invention provides a mechanical extension device for an anti-tilt seat unit, the mechanical extension device comprising:

[0005] A base unit fixedly arranged relative to the ground, comprising a base front beam and a base rear beam spaced apart from each other and extending parallel to each other, and the mechanical extension device is movably supported above the ground by the base unit;

[0006] a seat frame slidably movable relative to the base unit;

[0007] a leg extension pivotally connected to the front portion of the seat frame;

[0008] an electric drive unit; and

[0009] The anti-tilt mechanism includes an extension slide bar extending along the front-to-back direction of the seat unit and an auxiliary connecting rod fixedly connected to the front end of the extension slide bar and extending downward, wherein a support wheel supported on the ground is arranged at the free end of the auxiliary connecting rod. When the leg extension device moves along the front-to-back direction of the seat unit relative to the base unit, the anti-tilt mechanism moves synchronously along the front-to-back direction of the seat unit, thereby transforming the anti-tilt mechanism between an initial position and an extended position.

[0010] The forward extension of the leg extension device causes the overall length of the seat unit to increase, which is most likely to cause the risk of tilting forward due to the forward shift of the center of gravity. For this reason, the anti-tilt mechanism moves forward as the leg extension device moves forward, thereby expanding an additional support area in front of the seat unit, so that the seat unit is reliably supported by the support area to prevent the seat from tilting forward. In addition, the anti-tilt mechanism includes an extended slide rod extending forward and an auxiliary connecting rod extending downward from its front end, thereby allowing the anti-tilt mechanism to be arranged "suspended" above the base unit, so as not to occupy the space below the seat unit. Thus, even if the seat unit, especially its base unit and seat frame, are compact in height, it can ensure that sufficient space is provided below the seat unit for cleaning equipment, such as a sweeping robot, to perform cleaning work.

[0011] According to a preferred embodiment of the present invention, the base unit further comprises a front support leg extending downward from the front cross beam of the base and supported on the ground, and a rear support leg extending downward from the rear cross beam of the base and supported on the ground, wherein in the extended position of the anti-tilt mechanism, the support wheel is located in front of the front support leg. In the initial position, depending on the position setting of the front support leg, the support wheel can be located in front of the front support leg in close proximity to the front support leg, or can be retracted between the front support leg and the rear support leg.

[0012] According to a preferred embodiment of the present invention, the support wheel moves forward 200 mm to 500 mm in the extended position compared to the initial position, thereby providing as large an additional support space as possible, thereby reliably ensuring the anti-tilting effect.

[0013] According to a preferred embodiment of the present invention, the electric drive unit at least includes a motor head connected to the base unit, a motor slide rail and a motor slider that can slide along the motor slide rail, wherein the leg extension device and the extension slide rod are both connected to the motor slider, so that when the leg extension device moves along the front and rear direction of the seat unit, the support wheels synchronously roll on the ground along the front and rear direction of the seat unit.

[0014] According to a preferred embodiment of the present invention, the motor head is connected to a rear cross beam of the base of the base unit.

[0015] According to a preferred embodiment of the present invention, the leg extension device is pivotally connected to the motor slider via a motor connecting rod.

[0016] According to a preferred embodiment of the present invention, the anti-tilt mechanism comprises a slider connecting rod fixedly connected between the rear end of the extended slide rod and the motor slider. Preferably, the slider connecting rod is plate-shaped. Preferably, the slider connecting rod is fixedly connected between the rear end of the extended slide rod and the motor slider.

[0017] According to a preferred embodiment of the present invention, the anti-tilt mechanism includes a sliding bracket, the sliding bracket is fixedly connected to the front cross beam of the base, and the movement of the extended slide bar along the front-back direction of the seat unit is guided by the sliding bracket. Preferably, the sliding bracket includes a bracket body and a roller group, wherein the lower end of the bracket body is fixedly connected to the front cross beam of the base, and the roller group is arranged at the upper end of the bracket body. Preferably, the roller group includes at least two rollers arranged at intervals from each other in the height direction, thereby forming a accommodating portion for the extended slide bar, wherein the extended slide bar is rollingly supported between the at least two rollers. Thereby, the extended slide bar is directionally guided in the sliding bracket with low friction.

[0018] According to a preferred embodiment of the present invention, the sliding movement of the seat frame relative to the base unit is achieved by a sliding groove member and a matching sliding member that cooperate with each other. The matching sliding member can be configured as a slider or a roller, as long as the matching sliding member can be slidably supported in the sliding groove member to achieve sliding movement between the seat frame and the base unit.

[0019] To this end, preferably, 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 mating sliding member.

[0020] In one embodiment, the first slotted guide section extends in a straight line.

[0021] Alternatively, the first slotted guide section extends in a curved manner.

[0022] In the design according to the present invention, the motor rail of the electric drive unit is fixedly arranged below the seat frame relative to the base unit, and at the same time, the sliding movement of the seat frame relative to the base unit is performed along an upward trajectory, that is, during the transformation of the seat frame from its initial state to the slide-out state, the front part of the seat frame longitudinal beam rises to a greater extent than the rear part thereof, which makes the rear part of the seat frame at least not fall during the entire forward sliding process. This avoids interference between the electric drive unit and the seat frame during the posture transformation process. This allows the height of the front end of the seat frame to be appropriately lowered, without the need to obtain sufficient space under the seat by simply raising the height of the seat frame as in the prior art.

[0023] According to a preferred embodiment of the present invention, the mechanical extension device comprises a backrest unit, the backrest unit is pivotally connected between the base unit and the seat frame, and comprises a backrest bracket, a backrest connecting rod and a crank member, wherein the backrest bracket is used to attach the backrest of the seat unit, the backrest connecting rod comprises a first pivot point located at its upper end and a second pivot point located at its lower end, wherein the backrest connecting rod is pivotally connected to the front end of the backrest bracket at the first pivot point, pivotally connected to the seat frame at the second pivot point, and the upper end of the crank member is pivotally connected to the rear end of the backrest bracket at a third pivot point, and the lower end of the crank member is pivotally connected to the base unit at a fourth pivot point. Preferably, the crank member is connected to the base unit by a follower connecting rod.

[0024] According to a preferred embodiment of the present invention, the seat frame slides forward relative to the base unit so that the highest point of the backrest bracket tends to move downward and forward.

[0025] Since the backrest unit is pivotally connected between the seat frame and the base unit, and the seat frame and the base unit are slidably connected, the forward and backward sliding of the seat frame relative to the base unit will not cause the seat frame as a whole to rise or fall too much in the height direction. Different from the prior art, the seat frame according to the present invention only produces a relatively gentle height difference during the forward sliding process, which makes the backrest connecting rod not maintain a substantially same relative position with the seat frame when moving with the seat frame, but under the force of the rotation of the crank member, the backrest connecting rod moves forward with its upper end and approaches the longitudinal beam of the seat frame, so that the angle formed by the line between the first pivot point and the second pivot point and the longitudinal beam of the seat frame is reduced. This, on the one hand, drives the backrest bracket to move forward as a whole, realizing a complete "zero wall" arrangement of the seat unit, and on the other hand, makes the backrest unit approach the seat frame to a greater extent during the forward movement of the seat frame, realizing a "zero back rubbing" design. In addition, since the forward sliding of the seat frame relative to the base unit is performed along a nonlinear trajectory, the front part of the seat frame longitudinal beam is lifted upward to a greater extent than the rear part, thereby further lifting the leg extension device in a simple manner, which is more helpful in providing the user with a "zero gravity" experience.

[0026] According to a preferred embodiment of the present invention, the electric drive unit can be used to sequentially change the seat unit between a sitting position, a TV position and a lying position. The adjustment stroke achieved by the extension of the drive unit is divided into two stages that are implemented successively. In the first stage, the leg extension device is extended forward relative to the seat frame, and in the second stage, the seat frame slides forward relative to the base unit and the backrest bracket tilts backward, wherein during the first stage and the second stage, the support wheels of the anti-tilt mechanism continue to move forward.

[0027] Furthermore, the present invention also relates to a movable seat unit comprising the above-mentioned mechanical extension device.

[0028] 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

[0029] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] Figure 1 A perspective view schematically showing a mechanical extension device according to the invention in a sitting position;

[0031] Figure 2 Schematically shown Figure 1 TV position of the mechanical extension device shown;

[0032] Figure 3 Schematically shown in a stereogram Figure 1 The lying position of the mechanical extension device shown;

[0033] Figure 4 A perspective view schematically showing another angle of the mechanical extension device according to the present invention, which is in a sitting position;

[0034] Figure 5 Schematically shown Figure 4 TV position of the mechanical extension device shown;

[0035] Figure 6 Schematically shown Figure 4 The lying position of the mechanical extension device shown;

[0036] Figure 7 A schematic diagram showing an anti-tilt mechanism according to the present invention;

[0037] Figure 8 The sitting position of the mechanical extension device according to the present invention is shown in a side view;

[0038] Fig. 9 Schematically shown in side view Figure 8 the TV position of the mechanical extension device as shown; and

[0039] Fig.10 Schematically shown in side view Figure 8 The mechanical extension device is shown in the lying position. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may include one or more of the features explicitly or implicitly. 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 the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0042] Unless otherwise specified, the "front-rear direction" in this application refers to the extension direction of the leg unit of the furniture unit, especially the seat unit. Specifically, "front" refers to the direction toward the leg unit, and "rear" refers to the direction toward the backrest unit. "Left-right direction" or "lateral direction" refers to the direction of the furniture unit, especially the seat unit, which is perpendicular to the "front-rear direction" in the horizontal direction.

[0043] Figures 1 to 3 and Figures 4 to 6 The mechanical extension device of the movable seat unit according to the present invention is shown in three-dimensional views at different angles. Figures 8 to 10 The mechanical extension device of the seating unit according to the invention is shown in a side view.

[0044] The mechanical extension device includes a multi-link mechanism and is configured to enable the movable seat to be transformed between a sitting position, a TV position, and a lying position. However, the present invention is not limited thereto. In other embodiments not shown, the movable seat may also be transformed only between the stowed position and the TV position or only between the stowed position and the lying position.

[0045] The mechanical stretching device comprises a base unit 10 fixed relative to the ground, a seat frame 12 slidably movable relative to the base unit 10 , and a leg stretching device 3 pivotally connected to the front portion of the seat frame 12 .

[0046] In a preferred embodiment, the mechanical extension device also includes a backrest unit 2 pivotally connected to the rear portion of the seat frame 12, such as Figures 1 to 6 and Figures 8 to 9 However, in an embodiment not shown, a backrest unit may not be included, for example, a mechanical extension device for a "chaise longue" may not include a backrest, and accordingly, the mechanical extension device is not equipped with a backrest unit.

[0047] In one embodiment, the mechanical extension device is configured as a movable seat unit with floor-standing armrests. Figures 1 to 6 As shown, the seat frame includes two base longitudinal beams 101 extending in the front-to-back direction of the seat unit, a base front cross beam 102 and a base rear cross beam 103 extending transversely between the two base longitudinal beams 101, wherein the two base longitudinal beams 101, the base front cross beam 102 and the base rear cross beam 103 form a base frame, and four legs extend downward from the base unit 10, namely, two base front legs 104 and two base rear legs 105, so as to support the mechanical extension device "suspended" above the ground. In this embodiment, the four legs extend downward from the connection between the base front cross beam 102 and the base longitudinal beam and the base rear cross beam 103 and the base longitudinal beam, respectively, to provide as large a continuous space as possible under the base unit, so as not to hinder the passage of cleaning tools such as sweeping robots.

[0048] The seat frame 12 is used to carry the seat portion of the movable seat unit. The seat frame 12 includes two seat frame longitudinal beams 121 along the front-to-back direction of the seat unit, a seat frame front cross beam 122 and a seat frame rear cross beam 123 extending in different directions between the two seat frame longitudinal beams 121. In addition, the seat frame 12 also includes a seat frame rear extension 124 extending upward and fixedly arranged at the rear of the seat frame 12. The seat frame rear extension 124 can be integrally formed with the main body of the seat frame 12, or can be fixedly connected thereto as a separate component, for example, it can be fixedly installed by welding, riveting, etc.

[0049] In order to allow the seat frame 12 to slide relative to the base unit 10, the base unit 10 further includes a slide member 11, which is particularly arranged on its base longitudinal beam 101, wherein the slide member 11 includes at least two slide sections extending at different angles relative to the horizontal plane, namely, a first slide section 14a located in the front and a second slide section 14b located in the rear, and the angle between the first slide section 14a and the horizontal plane is greater than the angle between the second slide section 14b and the horizontal plane. In other words, the first slide section 14a is inclined at a larger angle than the second slide section 14b. In a preferred embodiment, the first slide section 14a and the second slide section 14b are jointly constructed as a continuous slide; however, in an alternative embodiment, the first slide section 14a and the second slide section 14b can also be constructed as two independent slides.

[0050] In this embodiment, the second slotted link section 14b preferably extends substantially parallel to the horizontal plane, and the rear end of the first slotted link section 14a and the front end of the second slotted link section 14b transition to each other at an angle, wherein the first slotted link section 14a is significantly inclined upward relative to the horizontal plane.

[0051] The seat frame longitudinal beam 121 of the seat frame 12 is configured to have a substantially L-shaped cross section, which includes a seat frame top surface 121a facing upward and a seat frame side surface 121b extending substantially perpendicular to the seat frame top surface 121a, wherein the seat frame top surface 121a is configured to support the seat portion, and at least two matching sliding members not specifically shown are rotatably mounted on the seat frame side surface 121b. In this embodiment, the matching sliding member is configured as a slider. The slider is movably embedded in the slide groove of the slide groove member 11, thereby allowing the seat frame 12 to slide relative to the base unit 10.

[0052] According to a preferred embodiment, the backrest unit 2 includes a backrest bracket 21 , a backrest link 22 , a crank member 23 and a follower link 24 , wherein the backrest unit 2 is pivotally connected between the seat frame 12 and the base unit 10 .

[0053] The upper part of the backrest bracket 21 is fixedly connected to a backrest frame (not specifically shown), wherein the backrest of the seat unit is fixedly attached to the backrest frame. A backrest connecting rod 22 is connected between the front end of the backrest bracket 21 and the seat frame 12, and a crank member 23 is connected between the rear end thereof and the seat frame 12.

[0054] The backrest link 22 is substantially straight, with its upper end pivotally connected to the front end of the backrest bracket 21 at a first pivot point P1 , and its lower end pivotally connected to the rear end of the seat frame 12 at a second pivot point P2 .

[0055] 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. Figure 4 and Figure 5 As shown, a third pivot point P3 is provided at the upper end of the crank member 23, a fourth pivot point P4 is provided at the lower end thereof, and a fifth pivot point P5 is provided at the middle thereof. The crank member 23 is pivotally connected to the rear end of the backrest bracket 21 at the third pivot point P3 by means of its upper end, and the crank member 23 is pivotally connected to the upper end of the follower link 24 at the fourth pivot point P4 at its lower end, and the follower link 24 is pivotally connected to the rear of the base unit 10 at its lower end. In addition, the crank member 23 is pivotally connected to the rear extension portion 124 of the seat frame at the fifth pivot point P5 at its middle, thereby being pivotally connected to the rear of the seat frame 12, wherein the fifth pivot point P5 is arranged further back than the second pivot point P2, that is, further away from the leg extension device 3 as viewed in the front-rear direction of the seat unit.

[0056] exist Figure 4 The sitting position shown and Figure 5 In the TV posture position shown in FIG. 1 , the first pivot point P1 of the backrest link 22 is further back in the horizontal direction relative to the second pivot point P2, that is, closer to the backrest; and in FIG. Figure 6 In the lying position shown, the first pivot point P1 of the backrest link 22 is further forward in the horizontal direction relative to the second pivot point P2, that is, closer to the direction of the leg extension device 3. This makes it possible that in the lying position, the angle α formed by the line between the first pivot point P1 and the second pivot point P2 of the backrest link 22 and the seat frame top surface 121 is significantly reduced compared to the sitting position and / or the TV position, such as in Figures 8 to 10 As shown schematically in FIG.

[0057] Especially Figure 5 and Figure 6 As shown, the leg extension device 3 includes a first link 31, a second link 32, a third link 33 and a fourth link 34, a connecting end surface 35 and an end surface 36 for attaching a footrest not specifically shown in the figure. 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. The first link 31 and the third link 33 are both rotatably mounted on the seat frame 12, wherein the pivot point between the first link 31 and the seat frame 12 is located behind the pivot point between the third link 33 and the seat frame 12. The footrest is rotatably connected to the second link 32 and the fourth link 34 by means of the connecting end surface 35 and the end surface 36. When the leg extension device 3 is unfolded, that is, as shown in FIG. Figure 5 The TV posture position shown and Figure 6 In the lying position shown, the third connecting rod 33 projects further forward than the first connecting rod 31 .

[0058] In order to enable the seat unit to be transformed between different positions, the mechanical extension device also comprises an electric drive unit 4 .

[0059] In such Figures 1 to 6In the illustrated embodiment, 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 configured as a linear actuator, which includes a motor head 41, a motor rail 42 fixedly connected to the motor head 41, a motor slider 43 that can slide along the motor rail 42 relative to the motor head 41, and a motor connecting rod 44. The motor head 41 is fixedly mounted on the rear part of the base frame 10, for example, it can be mounted on the base rear cross beam 103 of the base frame 10, or it can be mounted on the back plate of the seat unit fixed relative to the base frame 10; the motor slide rail 42 is fixedly connected to the base front cross beam 102 and the base rear cross beam 103 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 cross bar 37, wherein the motor cross bar 37 extends laterally between the leg extension device 3, for example, the motor cross bar 37 is fixedly attached to the third connecting rod 33 of the leg extension device 3 with its two ends, thereby realizing the movement synchronization of the leg extension devices on the left and right sides of the seat unit.

[0060] In the present embodiment, the electric drive unit 4 is designed to utilize a single electric actuator to cause the mechanical extension device of the seat unit to sequentially change between the sitting position, the TV position and the lying position.

[0061] When the seat unit and its mechanical extension device are transformed from a sitting position to a TV position or even a lying position, the leg extension device 3 is deployed forward, which causes the center of gravity of the mechanical extension device to move forward and brings the risk of the seat unit tilting forward. For this reason, the mechanical extension device also includes an anti-tilt mechanism 6.

[0062] Figure 7The figure shows the connection between the anti-tilt mechanism 6 and other parts of the mechanical extension device according to the present invention. The anti-tilt mechanism 6 includes a pair of extended slide bars 61 extending in the front-to-back direction of the seat unit and parallel to each other, and an auxiliary connecting rod 62 fixedly connected to the front end of the extended slide bar 61 and extending downward, wherein the auxiliary connecting rod 62 and the extended slide bar 61 are oriented perpendicular to each other. A support wheel 63 supported on the ground is arranged at the free end of the auxiliary connecting rod 62. The support wheel 63 rolls on the ground, thereby reducing the friction between the anti-tilt mechanism 6 and the ground. The rear end of the extended slide bar 61 is connected to the motor slider 43 by means of a slider connecting rod 65. The slider connecting rod 65 is plate-shaped and is fixedly connected to the motor slider 43 and the extended slide bar 61 by welding, riveting, threaded connection, etc., so that the extended slide bar 61 is driven to move synchronously while the motor slider 43 moves along the motor slide rail 42. At the same time, the motor slider 43 is also connected to the aforementioned motor connecting rod 44, the front end of which is pivotally connected to the motor cross bar 37, and the motor cross bar 37 is connected to the leg stretching device 3, so that when the leg stretching device 3 is stretched forward or retracted backward, the anti-tilt mechanism 6 slides forward or backward synchronously accordingly. In addition, the anti-tilt mechanism 6 also includes a sliding bracket 64, wherein the sliding bracket 64 includes a bracket body 641 and a roller group 642. Figure 7 As shown in the example, the lower end of the bracket body 641 is fixed on the front cross beam 102 of the base, wherein three rollers are arranged on the upper end of the bracket body 641, and the three rollers are divided into two rows, namely, two rollers located at the upper side and one roller located at the lower side, wherein a spacing is maintained between the rollers in the upper and lower rows to allow the extended slide bar 61 to be supported in a rolling manner in the accommodation portion thus formed. Therefore, during the movement of the extended slide bar 61 in the front-rear direction of the seat unit, the roller group 642 assists in directional guidance of the extended slide bar 61.

[0063] The following reference Figures 1 to 6 as well as Figures 8 to 10 The change of the mechanical extension device of the seat unit between the sitting position, the TV position and the lying position is introduced. During the change of the mechanical extension device from the sitting position to the lying position, the adjustment of the electric drive unit 4 is divided into two stages that are implemented in sequence, wherein the change from the sitting position to the TV position is realized in the first stage, and the change from the TV position to the lying position is realized in the second stage.

[0064] When the mechanical extension device is in Figure 1 , Figure 4 or Figure 8When in the sitting position shown, the backrest mounting member 21 of the backrest unit 2 stands upright, and an angle α is formed between the line between the first pivot point P1 and the second pivot point P2 of the backrest connecting rod 22 and the seat frame 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. The height of the support foot 104 can be set as needed, for example, it can be 5-15 cm, and accordingly, the height H1 of the front end of the seat frame 12 relative to the ground E0 can be selected to be 28-35 cm. Thus, the lowest point of the base unit 10, for example, the lowest point of the slide member 11 in this embodiment, is allowed to have a height H2 of 5-15 cm relative to the ground E0. 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 sweeping robot.

[0065] At this time, the anti-tilt mechanism 6 is in its initial position as a whole, wherein the extended slide bar 61 of the anti-tilt mechanism 6 is close to the rear of the seat unit, so that the auxiliary link 62 together with the support wheel 63 at its free end is located behind the front support leg 104. In this case, the length range of the effective support area of ​​the mechanical extension device corresponds to the length B0 between the front support 104 and the rear support leg 105. However, in an embodiment not shown, it is also conceivable that when the anti-tilt mechanism 6 is in its initial position, the auxiliary link 62 together with the support wheel 63 at its free end is located in front of the front support leg 104 in close proximity to the front support leg 104, that is, slightly in front of the front support leg 104. In this case, the length range of the effective support area of ​​the mechanical extension device corresponds to the length between the support wheel 63 and the rear support leg 105, rather than the length between the front support 104 and the rear support leg 105.

[0066] If the seat unit is to be Figure 1 , Figure 4 or Figure 8 The sitting position shown changes to Figure 2 , Figure 5 or Fig. 9 In the TV posture position shown, the mechanical extension device begins to extend under the action of the electric drive unit 4, wherein the electric drive unit 4 operates so that the motor slider 43 slides along the motor slide rail 42 away from the motor head 41, and pushes the motor cross bar 37 forward through the motor connecting rod 44, thereby unfolding the leg extension device 3. In 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, so the relative position between the backrest unit 2 and the seat frame 12 remains unchanged, wherein the angle α in the TV posture position remains unchanged from that in the sitting position. In this way, Figure 3 or Figure 6The TV posture position shown. That is to say, in the above-mentioned first stage, only the leg stretching device 3 is unfolded, while the relative position between the backrest unit 2 and the seat frame 12 remains unchanged, and the seat frame 12 does not move forward relative to the base unit 10, that is, the seat frame 12 still maintains its initial state. While the motor slider 43 drives the leg stretching device 3 to unfold, it also synchronously drives the extension slide bar 61 of the anti-tilt mechanism 6 to move forward, and then causes the support wheel 63 to roll forward. In this case, the support wheel 63 rolls to the front of the front support leg 104, and the length range of the effective support area of ​​the mechanical stretching device is equivalent to the length B1 between the support wheel 63 and the rear support leg 105. As a result, an additional support area is expanded in front of the front support leg 104, and even if the center of gravity of the seat unit moves forward to the above-mentioned additional support area in front of the front support leg 104 due to the extension of the leg stretching device 3, the seat unit can be effectively prevented from tilting forward.

[0067] In the mechanical extension device from Figure 2 , Figure 5 or Fig. 9 The TV posture position shown is transformed to Figure 3 , Figure 6 or Fig.10During the lying position shown, the electric drive unit 4 continues to operate, so that the motor slider 43 slides further away from the motor head 41 along the motor slide rail 42, so that the distance between the motor head 41 and the motor slider 43 is further increased. When the leg extension device 3 is extended forward to the 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, so as to change to the slide-out state of the seat frame 12. Since the first slide groove section 11a is inclined upward to a greater extent than the second slide groove section 11b relative to the horizontal plane, when the seat frame 12 slides forward, the front end of the seat frame 12 is lifted upward at a greater angle than the rear end, and its rear end at least does not fall, thereby effectively avoiding interference with the electric drive power source 4. In addition, when the seat frame 12 slides forward relative to the base unit 10, the crank member 23 rotates around the fifth pivot point P5 in the middle thereof, so that the angle α between the line between the first pivot point P1 and the second pivot point P2 of the backrest link 22 and the seat frame top surface 121 of the seat frame 12 is reduced. Thus, a lying position is achieved. In this process, on the one hand, the seat frame 12 itself moves forward, and on the other hand, the backrest bracket 21 also moves forward relative to the seat frame 12 by means of the linkage of the backrest connecting rod 22 and the crank member 23. Therefore, the backrest bracket 21 as a whole has a forward moving trajectory, wherein the rearmost end of the backrest bracket 21 and the top of the backrest bracket 21 both move significantly forward, thereby achieving "zero leaning against the wall". 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 bracket 21 tilts backward, and the leg extension device 3 extends further forward and upward with the seat frame 12, thereby achieving a "zero gravity" posture. In this process, as the leg extension device 3 moves further forward and upward, the center of gravity of the seat unit moves further forward. While the motor slider 43 drives the leg extension device 3 to move further forward, it also synchronously drives the extension slide bar 61 of the anti-tilt mechanism 6 to move further forward, thereby causing the support wheel 63 to roll further forward. In this case, the length B1 between the support wheel 63 and the rear support foot 105 is further increased compared to the TV posture position. Thus, the additional support area expanded in front of the front support foot 104 is also further increased.

[0068] Of course, for a seat unit that does not include a backrest unit and its mechanical extension device, the above-mentioned changes in the TV posture position and the lying position do not include changes in the backrest, but only involve different extension degrees of the leg extension device. When the leg extension device moves forward to the maximum extent in the front-to-back direction of the seat unit, the anti-tilt mechanism 6 reaches its extended position accordingly. Compared with the initial position of the anti-tilt mechanism 6, the support wheel 63 moves forward with a displacement of 200mm to 500mm in the extended position.

[0069] The corresponding reverse position change of the mechanical extension device of the seat unit is achieved by the contraction of the electric drive unit 4, and the adjustment stroke achieved thereby is also divided into two stages implemented successively. In the first stage, the seat frame 12 slides backward relative to the base unit 10, and the leg extension device 3 is correspondingly retracted, wherein the anti-tilt mechanism 6 is correspondingly retracted therefrom; in the second stage, the leg extension device 3 is further retracted backward relative to the seat frame 12, and the anti-tilt mechanism 6 is also correspondingly reset to its initial position. No further description is given here.

[0070] The above description has fully disclosed the specific embodiments of the present invention. It should be pointed out that any changes made by those skilled in the art to the specific embodiments of the present invention do not deviate from the scope of the claims of the present invention. Accordingly, the scope of the claims of the present invention is not limited to the above specific embodiments.

Claims

1. A mechanical extension device for a seat unit to prevent forward tilt, characterized in that: The mechanical stretching device comprises: A base unit fixedly arranged relative to the ground, comprising a base front beam and a base rear beam spaced apart from each other and extending parallel to each other, and the mechanical extension device is movably supported above the ground by the base unit; a seat frame slidably movable relative to the base unit; a leg extension pivotally connected to the front portion of the seat frame; an electric drive unit; and The anti-tilt mechanism includes an extension slide bar extending along the front-to-back direction of the seat unit and an auxiliary connecting rod fixedly connected to the front end of the extension slide bar and extending downward, wherein a support wheel supported on the ground is arranged at the free end of the auxiliary connecting rod. When the leg extension device moves along the front-to-back direction of the seat unit relative to the base unit, the anti-tilt mechanism moves synchronously along the front-to-back direction of the seat unit, thereby transforming the anti-tilt mechanism between an initial position and an extended position.

2. The mechanical stretching device according to claim 1, characterized in that: The base unit also includes a front support leg extending downward from the front cross beam of the base and supported on the ground, and a rear support leg extending downward from the rear cross beam of the base and supported on the ground, wherein in the extended position of the anti-tilt mechanism, the support wheel is located in front of the front support leg.

3. The mechanical stretching device according to claim 1, characterized in that: In the extended position, the support wheels are moved forward by 200 mm to 500 mm compared to the initial position.

4. The mechanical stretching device according to claim 1, characterized in that: The electric drive unit at least includes a motor head connected to the base unit, a motor slide rail and a motor slider that can slide along the motor slide rail, wherein the leg extension device and the extension slide rod are both connected to the motor slider, so that when the leg extension device moves along the front and rear direction of the seat unit, the support wheels synchronously roll on the ground along the front and rear direction of the seat unit.

5. The mechanical stretching device according to claim 4, characterized in that: The motor head is connected to the base rear cross beam of the base unit.

6. The mechanical stretching device according to claim 4, characterized in that: The leg extension device is pivotally connected to the motor slider via a motor connecting rod.

7. The mechanical stretching device according to claim 4, characterized in that: The anti-forward tilt mechanism comprises a slider connecting rod fixedly connected between the rear end of the extended slider and the motor slider.

8. The mechanical stretching device according to claim 7, characterized in that The slide connecting rod is designed in a plate-shaped manner.

9. The mechanical stretching device according to claim 7, characterized in that: The slider connecting rod is fixedly connected between the rear end of the extended slider and the motor slider.

10. The mechanical stretching device according to claim 1, characterized in that The anti-tilt mechanism comprises a sliding bracket, which is fixedly connected to the front cross beam of the base and guides the movement of the extended sliding rod along the front-rear direction of the seat unit.

11. The mechanical stretching device according to claim 10, characterized in that The sliding bracket comprises a bracket body and a roller group, wherein the lower end of the bracket body is fixedly connected to the front cross beam of the base, and the roller group is arranged at the upper end of the bracket body.

12. The mechanical stretching device according to claim 11, characterized in that The roller set comprises at least two rollers which are arranged spaced apart from each other in the height direction, thereby forming a receiving portion for the extension slide rod, wherein the extension slide rod is rollingly supported between the at least two rollers.

13. The mechanical stretching device according to claim 1, characterized in that The sliding movement of the seat frame relative to the base unit is achieved by means of a sliding groove member and a matching sliding member that cooperate with each other.

14. The mechanical stretching device according to claim 13, characterized in that 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 mating sliding member.

15. The mechanical stretching device according to claim 13, characterized in that The counter sliding element is configured as a roller or a sliding block.

16. The mechanical stretching device according to claim 15, characterized in that The first slotted guide section extends in a straight line.

17. The mechanical stretching device according to claim 15, characterized in that The first slotted guide section extends in a curved manner.

18. The mechanical stretching device according to claim 1, characterized in that The mechanical extension device includes a backrest unit, which is pivotally connected between the base unit and the seat frame, and includes a backrest bracket, a backrest connecting rod and a crank member, wherein the backrest bracket is used to attach the backrest of the seat unit, and the backrest connecting rod includes a first pivot point located at its upper end and a second pivot point located at its lower end, wherein the backrest connecting rod is pivotally connected to the front end of the backrest bracket at the first pivot point, and is pivotally connected to the seat frame at the second pivot point, and the upper end of the crank member is pivotally connected to the rear end of the backrest bracket at a third pivot point, and the lower end of the crank member is pivotally connected to the base unit at a fourth pivot point.

19. The mechanical stretching device according to claim 18, characterized in that The bell crank is connected to the base unit by a follower connecting rod.

20. The mechanical stretching device according to claim 18, characterized in that The seat frame slides forward relative to the base unit, so that the highest point of the backrest bracket has a tendency to move downward and forward.

21. The mechanical stretching device according to claim 18, characterized in that The electric drive unit can be used to sequentially switch the seat unit between a sitting position, a TV position and a lying position.

22. The mechanical stretching device according to claim 21, characterized in that The adjustment stroke achieved by the extension of the drive unit is divided into two stages implemented successively. In the first stage, the leg extension device is extended forward relative to the seat frame, and in the second stage, the seat frame slides forward relative to the base unit and the backrest bracket tilts backward. During the first stage and the second stage, the support wheels of the anti-tilt mechanism continue to move forward.

23. A movable seat unit, characterized in that: The seating unit comprises a mechanical extension device as claimed in any one of claims 1 to 22 above.

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