Mechanical stretching device for rocking seat and rocking seat

Abstract

The invention relates to a mechanical extension device for a rocking seat, comprising: a base unit; a rocker disposed above the base unit; the side plate is fixedly connected with the rocker, and the side plate can swing relative to the base unit by means of the rocker; a backrest bracket connected to a rear portion of the side panel at a first pivot point; a leg link pivotally connected to the front of the side panel; the backrest electric actuating device is designed to be used for enabling the backrest support to incline backwards and reset forwards relative to the side plate around a first pivot point; the leg electric actuating device is designed to be used for promoting the leg connecting rod to move forwards and backwards relative to the side plate; and a locking unit configured to approach the base unit by a backward tilt of the backrest bracket and / or a forward extension of the leg link, thereby restricting rocking of the side panel relative to the base unit. The invention also relates to a rocking seat.

Description

Technical Field

[0001] The present invention relates to a mechanical extension device for a rocking chair and a rocking chair. Background Art

[0002] Movable seats, such as rocking chairs, are increasingly used. As the requirements of users for comfort and safety continue to increase, rocking chairs are also equipped with more and more functions and safety measures. For example, some rocking chairs can be switched between a sitting position, a TV position, and a lying position. However, known rocking chairs often use one actuator. This results in the user being unable to adjust the support postures of the backrest or legs flexibly enough. In addition, there may be a risk of tipping over when the rocking chair rocks excessively. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a seat unit with a simpler structure, easier operation, and higher safety.

[0004] To solve the above technical problem, the present invention provides a mechanical extension device for a rocking chair, including: a base unit; a rocker arranged above the base unit; a side plate fixedly connected to the rocker, wherein the side plate can rock relative to the base unit by means of the rocker; a backrest bracket connected to the rear part of the side plate at a first pivot point; a leg link pivotally connected to the front part of the side plate; a backrest electric actuator designed to cause the backrest bracket to tilt backward and reset forward relative to the side plate around the first pivot point; a leg electric actuator designed to cause the leg link to move forward and backward relative to the side plate; and a locking unit configured to approach the base unit by the backward tilt of the backrest bracket and / or the forward extension of the leg link, thereby restricting the rocking of the side plate relative to the base unit.

[0005] According to the present invention, the backrest bracket and the leg link are respectively actuated by different electric actuators. Thus, the user can flexibly adjust the activities of the backrest and the footrest as needed. In addition, the setting of the locking unit improves the use safety. Especially when the backrest bracket tilts backward or when the leg link moves forward, the overall center of gravity of the rocking chair together with the seated user shifts. In this case, the locking unit can approach the base unit, thereby restricting the rocking of the side plate relative to the base unit and, if necessary, contacting the base unit, so as to prevent the rocker from rocking in the corresponding direction by a firm abutment.

[0006] According to a preferred embodiment, the locking unit includes a first locking device that moves relative to the side plate under the drive of the backrest electric actuator.

[0007] According to a preferred embodiment, the first locking device includes a first stop rod fixedly connected to the backrest bracket, wherein, by the backward tilting of the backrest bracket relative to the side plate, the free end of the first stop rod approaches the base unit.

[0008] According to a preferred embodiment, by the backward tilting of the backrest bracket relative to the side plate, the free end of the first stop rod abuts against the base unit.

[0009] According to a preferred embodiment, the first locking device further includes a first bushing disposed on the free end of the first stop rod.

[0010] In this embodiment, the first locking device prevents further backward tilting of the backrest bracket and prevents the backward rocking of the side plate together with the backrest bracket and the leg extension unit as a whole.

[0011] According to a preferred embodiment, the free end of the first stop rod is located below and behind the first pivot point, wherein, driven by the backrest electric actuating device, the free end of the first stop rod moves along an arc trajectory centered on the first pivot point.

[0012] Thus, when the backrest bracket tilts backward, the free end of the first stop rod generates a forward and downward arc-shaped movement trajectory. Thus, during the backward tilting of the backrest bracket, the free end of the first stop rod gradually approaches the base unit, and when the backrest bracket tilts backward to a predetermined limit, the free end of the first stop rod abuts against the base unit.

[0013] According to a preferred embodiment, the locking unit includes a second locking device that is movable relative to the side plate under the drive of the leg electric actuating device.

[0014] According to a preferred embodiment, the second locking device includes a second stop rod and a locking linkage rod, wherein the first end of the second stop rod is hinged to the side plate at a second pivot point and the second end projects freely, the front end of the locking linkage rod is pivotally connected to the leg link, and the rear end of the locking linkage rod is pivotally connected between the first end and the second end of the second stop rod, wherein, by the forward movement of the leg link relative to the side plate, the second end of the second stop rod approaches the base unit.

[0015] According to a preferred embodiment, by the forward movement of the leg link relative to the side plate, the second end of the second stop rod abuts against the base unit.

[0016] According to a preferred embodiment, the second locking device further includes a second bushing disposed on the second end of the second stop rod.

[0017] In this embodiment, the second locking device prevents further forward extension of the leg extension unit and prevents the side plate, together with the backrest bracket and the leg extension unit as a whole, from rocking backward.

[0018] According to a preferred embodiment, the second stop bar is configured as a V-shaped arm, wherein the rear end of the locking linkage is pivotally connected to the corner of the V-shaped arm.

[0019] According to a preferred embodiment, the opening direction of the V-shaped arm faces backward.

[0020] According to a preferred embodiment, the second end of the second stop bar is located below and behind the first end, and wherein, driven by the leg electric actuator, the second end of the second stop bar moves along an arc trajectory around the second pivot point.

[0021] In this embodiment, the second end of the second stop bar is a free end and is located below and behind the first end. Thus, when the leg link moves forward, the locking linkage drives the second stop bar to pivot around its first end, and its second end generates a forward and downward arc-shaped movement trajectory. Thus, during the forward movement of the leg link, the second end of the second stop bar gradually approaches the base unit, and when the leg link moves forward to a predetermined limit, the second end of the second stop bar abuts against the base unit.

[0022] According to a preferred embodiment, the side plate includes a guide groove, and the backrest bracket includes a guide pin adjacent to the first pivot point, wherein the guide pin is movably fitted in the guide groove.

[0023] According to a preferred embodiment, the guide pin can abut against at least one end of the guide groove to limit the pivoting angle of the backrest bracket relative to the side plate.

[0024] According to a preferred embodiment, one end of the backrest electric actuator is fixedly connected to the side plate, and the other end is connected to the backrest bracket.

[0025] According to a preferred embodiment, one end of the leg electric actuator is fixedly connected to the side plate, and the other end is connected to the leg link.

[0026] According to a preferred embodiment, the backrest electric actuator and the leg electric actuator are connected to a motor cross beam fixedly connected to the side plate.

[0027] According to a preferred embodiment, the rocker includes an upper surface fixedly connected to the side plate and a downwardly convex arc-shaped lower surface, wherein the lower surface contacts the base unit.

[0028] The present invention further provides a rocking chair, which includes the above mechanical extension device, a seat portion attached to the side plate, a backrest portion attached to the backrest bracket, and a footrest directly or indirectly connected to the leg link.

[0029] The advantages described above for the mechanical extension device also apply equally to the rocking chair having such a mechanical extension device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The embodiments of the present invention will be specifically described below with reference to the drawings.

[0031] Figure 1 A perspective view showing an embodiment of a mechanical extension device for a rocking chair according to the present invention, in a sitting position;

[0032] Figure 2 Shown Figure 1 A perspective view of the mechanical extension device shown from another angle, in an initial position;

[0033] Figure 3 Shown Figure 2 A perspective view of the mechanical extension device shown, in a fully extended position;

[0034] Figure 4 Shown Figure 2 A partially enlarged view of the mechanical extension device shown;

[0035] Figure 5 Shown Figure 3 A partially enlarged view of the mechanical extension device shown;

[0036] Figure 6 A partial side view showing a mechanical extension device according to the present invention, in which the backrest unit is not tilted backward relative to the side plate;

[0037] Figure 7 A partial side view showing a mechanical extension device according to the present invention, in which the backrest unit is tilted backward relative to the side plate;

[0038] Figure 8 A perspective view showing another embodiment of a mechanical extension device according to the present invention, in a sitting position;

[0039] Figure 9 Shown Figure 8 A perspective view of the mechanical extension device shown from another angle, in an initial position;

[0040] Figure 10 Shown Figure 9 A perspective view of the mechanical extension device shown, in a fully extended position;

[0041] Figure 11 A partial side view of a mechanical stretching device according to the present invention is shown, in which its leg stretching unit stretches forward relative to the side plate; and

[0042] Figure 12 A partial side view of a mechanical stretching device according to the present invention is shown, in which its backrest unit folds backward relative to the side plate. Detailed implementation manners

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] As used herein, the term "one embodiment" or "embodiment" 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 drawings, and 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 should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. Moreover, the terms "first", "second", etc. are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order different from those illustrated or described herein.

[0045] In addition, it should be noted here that the "front-back direction" and "front and back" mentioned in this application refer to the stretching direction of the seat unit or the leg stretching unit of the mechanical stretching device. Specifically, "front" refers to the direction towards the leg stretching unit, and "rear" refers to the direction towards the backrest; the "left-right direction" and "left and right" refer to the left and right hand directions when the user of the seat unit or the mechanical stretching device is seated.

[0046] The mechanical extension device according to the present invention is applicable to a rocking chair. The mechanical extension device 100 includes a base unit 10, a rocking unit 20, side plates 30, a backrest unit 40, a leg extension unit 50, and an actuating unit 60. Among them, the actuating unit 60 includes a backrest electro-actuator 61 and a leg electro-actuator 62 for adjusting the backrest unit 40 and the leg extension unit 50 respectively.

[0047] The base unit 10 may at least include two parallel base longitudinal beams 11 as Figures 1 to 3 shown. The base longitudinal beams 11 extend in the front-rear direction of the seat unit as a whole. The mechanical extension device 100 is firmly supported on the ground by means of its base unit 10.

[0048] The rocking unit 20 may include a rocker 21 as Figures 1 to 3 shown. The rocker 21 includes a flat upper surface and an arcuate convex lower surface. Among them, the upper surface is used for fixedly connecting to the side plates 30, and the lower surface is rotatably supported on the base longitudinal beams 11 of the base unit 10. The rocking mechanism 20 may further include an L-shaped rocking mounting plate 22. Its vertically upward section is fixedly connected to the side plates 30, and its horizontally extending section is fixedly connected to the upper surface of the rocker 21. Of course, in an embodiment not shown, the side plates 30 may also be fixedly connected to the rocker 21 by means of a plurality of angle irons or rivets, etc.

[0049] The rocking unit 20 may further include a spring assembly 23 as Figure 4 shown. Among them, the spring assembly 23 may include one or more springs. The spring assembly 23 is arranged adjacent to the rocker 21 and connected to the rocker 21, so as to play a buffering and resetting function when the rocker 21 together with the side plates 30 rocks back and forth relative to the base unit 10.

[0050] In particular, as Figure 4 shown, the side plates 30 may include a first side plate section 31, a second side plate section 32, and a third side plate section 33 that are rigidly connected to each other. The first side plate section 31 may be V-shaped and is designed to be attached to the seat part of the rocking chair. The second side plate section 32 is fixedly connected to the rear half of the first side plate section 31. As Figure 4 shown, the second side plate section 32 includes an extended part with a guide groove 321 extending backward. The third side plate section 33 includes two ends that are respectively upturned and an intermediate section extending between the two ends. Among them, the two ends of the third side plate section 33 are respectively fixedly connected to the front end of the first side plate section 31 and the rear end of the second side plate section 32, and the intermediate section of the third side plate section 3 is fixedly connected to the rocking mounting plate 22 of the rocking unit 20. Thus, the side plates 30 are connected to the rocker 21 as a rigid whole.

[0051] In this embodiment, the first side plate section 31, the second side plate section 32 and the third side plate section 33 are connected to each other by means of welding, riveting, screw connection or the like. Of course, in an embodiment not shown, the side plate 30 may also be integrally formed by means of casting.

[0052] The backrest unit 40 includes a backrest bracket 41. In this embodiment, the backrest bracket 41 includes a first section protruding forward and a second section extending upward. Wherein, the backrest bracket 41 is pivotally connected to the rear part of the side plate 30 at a first pivot point P1 by means of its first section, and the backrest bracket 41 is fixedly connected to the backrest of a rockable seat (not shown in the figure) by means of its second section. The backrest bracket 41 further includes a guide pin 411 located on its first section. The guide pin 411 is offset backward relative to the first pivot point P1 and is movably embedded in a guide groove 321 of the second side plate section 32 of the side plate 30. Through the cooperation of the guide groove 321 and the guide pin 411, the pivoting angle of the backrest bracket 41 around the first pivot point P1 relative to the side plate 30 can be restricted. For example, in Figure 4 the state shown, the backrest bracket 41 has not tilted backward relative to the side plate 30, and the guide pin 411 is located at the upper end of the guide groove 321; in Figure 5 the state shown, by pivoting the backrest bracket 41 around the first pivot point P1 in the clockwise direction, the guide pin 411 abuts against the lower end of the guide groove 321, whereby the backrest bracket 41 cannot continue to pivot around the first pivot point P1 in the clockwise direction, thus restricting the degree of backward tilt of the backrest bracket 41.

[0053] The backrest cross beam 43 extends horizontally between the two backrest brackets 41 and is fixedly connected to the backrest brackets 41 at its two ends respectively. In this embodiment, as Figure 4 、 Figure 5 shown, the backrest cross beam 43 is fixedly connected to the backrest brackets 41 especially at its two ends by means of backrest connecting pieces 42. The backrest connecting pieces 42 can be fixedly connected to the backrest brackets 41 by means of riveting, screw connection, welding or the like. In an embodiment not shown, the backrest brackets 41 and the backrest connecting pieces 42 may also be integrally formed by means of casting.

[0054] The leg extension unit 50 is pivotally connected to the front part of the side plate 30 and can extend forward and retract backward relative to the side plate 30, thereby driving the footrest to move forward and reset backward relative to the side plate 30. The leg extension unit 50 includes at least one leg link, and the leg link can move forward or backward under the drive of a leg electric actuator 62.

[0055] According to the present invention, the leg extension unit 50 can be constructed in various ways.

[0056] For example, in one embodiment, asFigure 9 and Figure 10 As shown in Figure 10 , the leg extension unit 50 may include a multi-link mechanism. The multi-link mechanism includes a first leg link 51, a second leg link 52, a third leg link 53, a fourth leg link 54, and a footrest 55. The rear ends of the first leg link 51 and the second leg link 52 are respectively pivotally connected to the front portion of the side plate 30. Among them, the hinge point of the first leg link 51 and the side plate 30 is more rearward than the hinge point of the second leg link 50 and the side plate 30. The rear end of the third leg link 53 is hinged to the front end of the first leg link 51, and the rear end of the fourth leg link 54 is hinged to the front end of the second leg link 52. The front ends of the third leg link 53 and the fourth leg link 54 are respectively hinged to the footrest 55. The footrest 55 is used to attach the footstool of a rockable seat (not shown in the figure). By the forward extension and backward retraction of the leg extension unit 50 relative to the side plate 30, the footstool is correspondingly lifted forward and reset backward relative to the side plate 30.

[0057] The leg extension unit 50 further includes a laterally extending leg cross beam 56. The leg cross beam 56 is connected to the multi-link mechanisms on the left and right sides at its ends. In this embodiment, the leg cross beam 56 is connected to the second leg link 52. However, in an embodiment not shown, the leg cross beam 56 may also be connected to other components of the multi-link mechanism, such as between the second leg link 52, the third leg link 53, or the fourth leg link 54.

[0058] As an alternative, for example, in an embodiment not shown, the leg extension unit 50 may also include only one leg link and a footrest 55. Among them, the front end of the leg link is hinged to the footrest 55, and the rear end of the leg link is pivotally connected to the front portion of the side plate 30. The leg cross beam 56 is correspondingly connected between the leg links on the left and right sides. By the forward and backward movement of the leg link relative to the side plate 30, the footstool is correspondingly lifted forward and reset backward relative to the side plate 30.

[0059] The backrest electro - actuating device 61 includes a backrest motor 611 and a backrest actuating rod 612 that is telescopic relative to the backrest motor 611. The leg electro - actuating device 62 includes a leg motor 621 and a leg actuating rod 622 that is telescopic relative to the leg motor 621. One end of the backrest electro - actuating device 61 is connected to the backrest cross - beam 43, and the other end is connected to the side plate 30; one end of the leg electro - actuating device 62 is connected to the leg cross - beam 56, and the other end is also connected to the side plate 30. For example, in this embodiment, the backrest electro - actuating device 61 has its backrest actuating rod 612 connected to the backrest cross - beam 43, and the backrest motor 611 is connected to the motor cross - beam 34. The leg electro - actuating device 62 has its leg motor 621 connected to the leg cross - beam 56, and the leg actuating rod 622 is connected to the motor cross - beam 34, wherein the motor cross - beam 34 is transversely connected and fixedly connected to the second side - plate section 32 of the side plate 30 at its two ends.

[0060] By actuating the backrest electro - actuating device 61, the backrest cross - beam 43 moves away from or closer to the motor cross - beam 34, thereby causing the backrest support 41 to tilt backward or reset forward relative to the side plate 30. By actuating the leg electro - actuating device 62, the leg cross - beam 56 moves away from or closer to the motor cross - beam 34, thereby causing the leg extension unit 50 to extend forward or retract backward relative to the side plate 30.

[0061] The backrest electro - actuating device 61 and the leg electro - actuating device 62 can be actuated independently of each other, thereby allowing the user to adjust the backrest unit and the leg extension unit independently according to needs.

[0062] To improve the safety of the rocking chair, the mechanical extension device further includes a locking unit 70.

[0063] The locking unit 70 is configured to come into contact with the base unit 10 through the backward tilt of the backrest support 41 and / or the forward extension of the leg extension unit 50, thereby restricting the rocking of the side plate 30 relative to the base unit 10.

[0064] The locking unit 70 may include Figures 1 to 7 the first locking device 71 shown. As an alternative or supplement, the locking unit 70 may further include Figures 8 to 12 the second locking device 72 shown.

[0065] The first locking device 71 moves relative to the side plate 30 under the drive of the backrest electro - actuating device 61. The first locking device 71 includes a first stop rod 711, wherein the first stop rod 711 is fixedly connected to the backrest support 41. Especially as Figure 4 and Figure 5As described above, the first stop lever 711 is configured as a downward extension of the backrest tab 42. Thus, the first stop lever 711 is fixedly connected to the backrest support 41. However, in an embodiment not shown, the first stop lever 711 may also be integrally formed with the backrest support 41 and the backrest tab 42. The free end of the first stop lever 711 protrudes downward and includes a first bushing 712.

[0066] A first connecting line L1 between the free end of the first stop lever 711 and the first pivot point P1 is inclined with respect to the vertical direction, wherein the free end of the first stop lever 711 is located below and behind the first pivot point P1. When the backrest actuating device 61 causes the backrest support 41 to tilt backward, the free end of the first stop lever 711 moves forward and downward along an arc trajectory centered on the first pivot point P1. During this process, the free end of the first stop lever 711 approaches the base unit 10 and finally contacts the base unit 10.

[0067] As Figure 6 shown, when the backrest support 41 is not tilted backward relative to the side plate 30, the free end of the first stop lever 711 maintains a spacing relative to the base unit 10. In this case, it is allowed to rock the side plate 30 together with the backrest unit 40 relative to the base unit 10 by means of the rocking unit 20. As Figure 7 shown, when the backrest actuating device 61 causes the backrest support 41 to tilt backward clockwise about the first pivot point P1, the first stop lever 711 moves downward and forward clockwise along with the backrest support 41, thereby approaching the base unit 10 and finally contacting the base unit 10. Thus, by the abutment of the first stop lever 711 against the base unit 10, the further backward tilting of the backrest support 41 is prevented, and the backward rocking of the side plate 30 relative to the base unit 10 is prevented.

[0068] The second locking device 72 is movable relative to the side plate 30 under the drive of the leg actuating device 62. The second locking device 72 includes a second stop lever 721 and a locking linkage 723. The first end of the second stop lever 721 is hinged to the side plate 30 at a second pivot point P2 and the second end protrudes freely. The second stop lever 721 may also include a second bushing 722 arranged at its free end, i.e., its second end. The front end of the locking linkage 723 is pivotally connected to a leg link of the leg extension unit 50, for example, pivotally connected to the first leg link 51, and the rear end of the locking linkage 723 is pivotally connected between the first end and the second end of the second stop lever 721. In this embodiment, the second stop lever 721 is configured as a V-shaped arm with an opening direction backward, wherein the rear end of the locking linkage 723 is pivotally connected to the corner of the V-shaped arm. Alternatively, in an embodiment not shown, the second stop lever 721 may also extend substantially linearly.

[0069] The second connection line L2 between the first end and the second end of the second stop lever 721 is inclined relative to the vertical direction, wherein the second end of the second stop lever 721 is located below and behind the first end. When the leg electro-actuator 62 urges the leg extension unit 50 to extend forward, the locking linkage 723 moves forward under the drive of the leg link connected thereto, such as the first leg link 51, and urges the second end of the second stop lever 721 to move forward and downward along an arc trajectory centered on the second pivot point P2. During this process, the second end of the second stop lever 721 approaches the base unit 10 and finally contacts the base unit 10.

[0070] As Figure 11 shown, when the leg extension unit 50 does not extend forward relative to the side plate 30, that is, when the leg extension unit 50 is retracted relative to the side 30, the second end of the second stop lever 721 maintains a distance from the base unit 10. In this case, it is allowed to achieve the forward and backward rocking of the side plate 30 together with the backrest unit 40 relative to the base unit 10 by means of the rocking unit 20. When the leg electro-actuator 62 urges the leg extension unit 50 to extend forward, the second end of the second stop lever 721 moves forward and downward in the clockwise direction, so as to approach the base unit 10 and finally contact the base unit 10, as Figure 12 shown. Thus, by the abutment of the second stop lever 721 against the base unit 10, the further forward extension of the leg extension unit 50 is prevented, and the backward rocking of the side plate 30 relative to the base unit 10 is prevented.

[0071] Here, the locking unit 70 may include only one of the first locking device 71 and the second locking device 72, or may include both the first locking device 71 and the second locking device 72.

[0072] As described above, only the specific embodiments of the present invention are provided, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A mechanical extension device for a rockable seat, comprising: A base unit; A rocker arranged above the base unit; A side plate fixedly connected to the rocker, wherein the side plate can rock relative to the base unit by means of the rocker; A backrest bracket connected to the rear part of the side plate at a first pivot point; A leg link pivotally connected to the front part of the side plate; A backrest electric actuating device designed to cause the backrest bracket to tilt backward and reset forward relative to the side plate about the first pivot point; A leg electric actuating device designed to cause the leg link to move forward and backward relative to the side plate; and A locking unit configured to approach the base unit by the backward tilt of the backrest bracket and / or the forward extension of the leg link, thereby restricting the rocking of the side plate relative to the base unit.

2. The mechanical stretching device according to claim 1, characterized in that, The locking unit includes a first locking device movable relative to the side plate under the drive of the backrest electric actuating device.

3. The mechanical stretching device according to claim 2, wherein The first locking device includes a first stop rod fixedly connected to the backrest bracket, wherein, by the backward tilt of the backrest bracket relative to the side plate, the free end of the first stop rod approaches the base unit.

4. The mechanical extension device according to claim 3, characterized in that, By the backward tilt of the backrest bracket relative to the side plate, the free end of the first stop rod abuts against the base unit.

5. The mechanical extension device according to claim 3, wherein, The first locking device further includes a first bushing arranged on the free end of the first stop rod.

6. The mechanical extension device according to claim 3, wherein The free end of the first stop rod is located below and behind the first pivot point, wherein, under the drive of the backrest electric actuating device, the free end of the first stop rod moves along an arc trajectory centered on the first pivot point.

7. The mechanical stretching device according to claim 1, characterized in that, The locking unit includes a second locking device movable relative to the side plate under the drive of the leg electric actuating device.

8. The mechanical extension device according to claim 7, wherein The second locking device includes a second stop rod and a locking linkage rod, wherein the first end of the second stop rod is hinged to the side plate at a second pivot point and the second end projects freely, the front end of the locking linkage rod is pivotally connected to the leg link, and the rear end of the locking linkage rod is pivotally connected between the first end and the second end of the second stop rod, wherein, by the forward movement of the leg link relative to the side plate, the second end of the second stop rod approaches the base unit.

9. The mechanical extension device according to claim 8, wherein, By the forward movement of the leg link relative to the side plate, the second end of the second stop rod abuts against the base unit.

10. The mechanical stretching device according to claim 8, wherein The second locking device further includes a second bushing arranged on the second end of the second stop rod.

11. The mechanical stretching device according to claim 8, wherein, The second stop rod is configured as a V-shaped arm, wherein the rear end of the locking linkage rod is pivotally connected to the corner of the V-shaped arm.

12. The mechanical extension device according to claim 11, wherein, The opening direction of the V-shaped arm is backward.

13. The mechanical extension device according to claim 8, wherein, The second end of the second stop rod is located below and behind the first end, wherein, under the drive of the leg electric actuating device, the second end of the second stop rod moves along an arc trajectory around the second pivot point.

14. The mechanical extension device according to claim 1, characterized in that, The side plate includes a guide groove, and the backrest bracket includes a guide pin adjacent to the first pivot point, wherein the guide pin is movably fitted in the guide groove.

15. The mechanical stretching device according to claim 14, wherein, The guide pin can abut against at least one end of the guide groove to limit the pivoting angle of the backrest bracket relative to the side plate.

16. The mechanical extension device according to claim 1, wherein One end of the backrest electric actuator is fixedly connected to the side plate, and the other end is connected to the backrest bracket.

17. The mechanical extension device according to claim 16, wherein One end of the leg electric actuator is fixedly connected to the side plate, and the other end is connected to the leg link.

18. The mechanical extension device according to claim 17, characterized in that, The backrest electric actuator and the leg electric actuator are connected to a motor crossbeam fixedly connected to the side plate.

19. The mechanical stretching device according to claim 1, characterized in that, The rocker includes an upper surface fixedly connected to the side plate and a downwardly convex arcuate lower surface, wherein the lower surface contacts the base unit.

20. A rockable seat, comprising the mechanical extension device according to any one of claims 1 to 19 above, a seat portion attached to the side plate, a backrest portion attached to the backrest bracket, and a footrest directly or indirectly connected to the leg link.

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