Foot support mechanism hidden at bottom of seat

Abstract

The invention provides a foot support mechanism hidden at the bottom of a seat, a gap exists between the bottom of the seat and a vehicle body floor, the foot support mechanism is arranged in the gap, and the foot support mechanism comprises an extending mechanism, a folding mechanism and a locking mechanism; the extending mechanism comprises a driving mechanism, a gap bridge support and a mounting support, the driving mechanism is fixed to the mounting support, the gap bridge support is connected to the mounting support in a front-back sliding mode, the folding mechanism comprises a supporting metal plate and an overturning assembly, and the supporting metal plate is installed on the gap bridge support through the overturning assembly and is in a flat state; the driving mechanism is connected with the supporting metal plate and can drive the supporting metal plate and the gap bridge support to move backwards together, when the supporting metal plate completely extends out of the seat, the locking mechanism can achieve backward sliding locking of the gap bridge support, and at the moment, the driving mechanism continues to work and can drive the supporting metal plate to be folded upwards so that the supporting metal plate can be in a supporting state with the front portion higher than the rear portion. According to the invention, more comfortable and stable footstep support can be provided for passengers in the back row, and space utilization of seats in the front row is optimized at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile seats, in particular to a footrest mechanism hidden at the bottom of a seat. Background Art

[0002] As the automotive industry continues to develop, car seats, as an important component of the vehicle interior, are increasingly attracting consumers' attention for their functionality and comfort. Among these, footrests, which provide comfortable foot support for rear passengers, have become a key factor in enhancing the riding experience.

[0003] Currently, most footrests integrated into car seats on the market are fixed to the seatback and tilted up and down to provide foot support for rear passengers. These footrests are typically fixed to the lower backrest of the front seat. However, this design presents several drawbacks. First, because the footrest is connected to the front seat, it moves up and down when the front seat is adjusted. Furthermore, adjusting the front seatback's angle also affects the footrest's opening angle. This interlocking mechanism makes it difficult for rear passengers to achieve a stable and comfortable footrest angle, significantly impacting ride comfort. Furthermore, with increasing demands for car seat functionality, front seats often require both a tray table and a footrest behind the backrest to accommodate the diverse needs of rear passengers. However, this configuration places greater demands on the front backrest's space. Given a given backrest height, both the tray table and the footrest occupy a certain amount of space, creating competition for space and making it difficult to meet the required dimensions for both. Summary of the Invention

[0004] In response to the above-mentioned problems existing in the prior art, the present invention aims to provide a footrest mechanism hidden at the bottom of the seat, which can provide more comfortable and stable foot support for rear passengers while optimizing the space utilization of the front seats.

[0005] In order to achieve the above-mentioned purpose, the present invention proposes a footrest mechanism hidden in the bottom of the seat, there is a gap between the bottom of the seat and the vehicle body floor, the footrest mechanism is arranged in the gap and fixed to the seat, the footrest mechanism includes an extension mechanism, a folding mechanism and a locking mechanism; the extension mechanism includes a driving mechanism, a bridge bracket and a mounting bracket for fixing to the bottom of the seat, the driving mechanism is fixed to the mounting bracket, the bridge bracket is connected to the mounting bracket for sliding back and forth, the folding mechanism includes a supporting sheet metal and a flipping assembly, the supporting sheet metal is installed on the bridge bracket through the flipping assembly and is in a flat state, the driving mechanism is connected to the supporting sheet metal and can drive it to move backward together with the bridge bracket, when the supporting sheet metal is fully extended from the seat, the locking mechanism can realize the backward sliding locking of the bridge bracket, at this time the driving mechanism continues to work to drive the supporting sheet metal to fold upward, so that it forms a support state with high front and low back.

[0006] In the above solution, the seat bottom is equipped with a slide mechanism, which typically comprises left and right slide assemblies. A single slide assembly comprises an upper and lower slide rail that slide relative to each other. The seat bottom is secured to the two upper slide rails via two upper slide rail brackets, with the mounting bracket secured between the two upper slide rails. This design facilitates installation of the footrest mechanism and ensures a secure connection to the seat. During the seat's sliding motion, the footrest mechanism remains stable and functions properly, providing reliable foot support for rear passengers. It does not move up or down with front seat height adjustment, nor does it affect the opening angle of the front seatback.

[0007] In the above scheme: the mounting bracket includes two longitudinal brackets and a transverse bracket connected between the front ends of the two longitudinal brackets. The cross-section of the two longitudinal brackets is U-shaped, and the inner side walls thereof are provided with outer drawer rails extending forward and backward. The two ends of the bridge bracket respectively cooperate with the two outer drawer rails through the inner drawer rails, thereby sliding back and forth and connecting between the two longitudinal brackets. The outer side walls of the two longitudinal brackets are provided with mounting holes for driving bolts. The drawer rail sliding connection method can ensure that the bridge bracket slides back and forth stably and smoothly between the longitudinal brackets, reducing jamming and shaking during the sliding process. The outer side walls of the two longitudinal brackets are provided with mounting holes for driving bolts. Through these mounting holes, the mounting bracket can be conveniently fixed to a suitable position on the bottom of the seat. The installation process is simple and easy to operate.

[0008] The cam is connected to the two longitudinal supports of the two levers, and the front ends of the two levers are connected to the support rails of the vehicle frame by a rotation of the crankshaft and the support rails, and the cam is connected to the support rails by a turning assembly. When the cam is turned on, the lever is connected to the support rails by a turning assembly. When the cam is turned on, the lever is connected to the support rails by a turning assembly. When the cam is turned on, the lever is connected to the support rails by a turning assembly. The multi-link hinge mechanism design allows the footrest mechanism to have a larger range of motion. Through the relative rotation and sliding between the links, it can meet the needs of supporting the sheet metal to extend from the bottom of the seat to the appropriate position.

[0009] In the above scheme: the flip assembly includes two lower end supporting swing arms and two upper end supporting swing arms, and a rotating swing arm, the two ends of the bridge bracket extend forward to form an extension section, and the two extension sections are provided with first guide grooves extending front and back relative to each other on the left and right sides. The lower ends of the two upper end supporting swing arms are limited in the two first guide grooves by the sliding of the swing arm rotating shaft and can rotate along them. The upper ends of the two upper end supporting swing arms are hinged to the two sides of the bottom front end of the supporting sheet metal, and the lower ends of the two lower end supporting swing arms are hinged to the two sides of the rear end of the bridge bracket by connecting the rear bracket. The upper ends of the support arms are welded to the rear ends of the bottom surface of the support sheet metal on both sides. The upper ends of the rotating arm are hinged to the middle of the bottom surface of the support sheet metal via step bolts or rivets. The lower end of the rotating arm is vertically hinged to the connecting front bracket, which is horizontally connected to it at the cross hinge of the two third links. When the bridge bracket slides backward and locks, and the extension motor drives the extension hinge mechanism to continue to extend backward, it can drive the rotating arm to flip upward, thereby driving the support sheet metal, the lower support arm, and the upper support arm to move together to achieve folding of the support sheet metal. This design can flexibly adjust the folding angle of the support sheet metal. In actual use, the folding angle of the support sheet metal can be precisely controlled according to the needs of the rear passengers and the adjustment of the seats, providing passengers with a more personalized comfort experience. The opening angle of the support sheet metal can range from 0 to 40 degrees, and the specific design adjustment can be based on actual needs.

[0010] The two cams are connected to each other by a bolt, and the bolt has a round shank to move along the two cams to move the two cams together, so that the cams can move relative to each other, thereby preventing the cams from sliding off and entering the locking cam. It is arranged in each of the first guide groove, the second guide groove and the oblique guide groove; when the supporting sheet metal is in a horizontal state, the locking shaft is located at the rear end of the first guide groove, the front end of the second guide groove and the lowest end of the oblique guide groove. When the bridge bracket moves backward, the locking shaft can move forward relative to the first guide groove and move backward relative to the second guide groove. When the supporting sheet metal is fully extended out of the seat, the locking shaft just slides to the rear end of the second guide groove and the front end of the first guide groove to realize the backward sliding locking of the bridge bracket. At this time, the extension motor drives the extension hinge mechanism to continue to extend backward, and the locking shaft can slide obliquely upward relative to the lowest end of the oblique guide groove, thereby sliding into the locking section of the first guide groove and the second guide groove.

[0011] On the one hand, the design of the oblique guide groove ensures that after the bridge bracket is slid and locked, the locking shaft will not interfere with the continued backward movement of the extending hinge mechanism, and the extending hinge mechanism can move backward relative to the locking shaft.

[0012] On the other hand, the design of the oblique guide groove enables the locking shaft to slide into the locking sections of the first guide groove and the second guide groove to achieve interlocking of the bridge bracket and the sliding locking sheet metal, thereby enhancing the impact resistance of the locking mechanism.

[0013] In the above solution, the longitudinal brackets are integrally formed with the outer drawer rails, the bridge brackets are integrally formed with the inner drawer rails, and the inner drawer rails are located outside the corresponding side extensions. The fixed brackets are connected between the bottom surfaces of the two longitudinal brackets, and the fixed lugs are fixed to the bottom surfaces of the corresponding longitudinal brackets. This integrated design makes the entire structure more robust, capable of withstanding greater forces and vibrations, and improves the reliability and durability of the footrest mechanism. The fixed brackets are connected between the bottom surfaces of the two longitudinal brackets, and the fixed lugs are fixed to the bottom surfaces of the corresponding longitudinal brackets. This means that the fixed brackets, fixed lugs, and the extension hinge mechanism are staggered to prevent interference with the extension hinge mechanism.

[0014] In the above scheme: the front connecting bracket and the rear connecting bracket are both "L"-shaped, the lower end of the rotating swing arm is vertically hinged to the vertical section of the front connecting bracket, the horizontal section of the front connecting bracket is horizontally rotatably connected to it at the cross hinge of the two third connecting rods, the horizontal section of the rear connecting bracket is welded to the bridge bracket, and the lower end of the lower end supporting swing arm is vertically hinged to the vertical section of the corresponding side connecting rear bracket. The structure is simple and easy to install.

[0015] The beneficial effects of the present invention are:

[0016] 1. The footrest mechanism is cleverly positioned in the gap between the seat bottom and the vehicle floor and fixed to the seat. This design fully utilizes previously unused space, effectively resolving the existing space competition caused by the simultaneous placement of a tray table and footrest mechanism in the front seats, thereby improving interior space utilization. 2. Because the footrest mechanism is independent of the seatback, it does not move up or down with front seat height adjustment, nor does its opening angle change with front seatback angle adjustments. This ensures stable and comfortable support for rear passengers when using the footrest. Regardless of front seat adjustment, the footrest maintains a relatively fixed position and angle, providing a more convenient and comfortable user experience. 3. By cleverly integrating a lead screw and hinge structure, the footrest's sliding range is effectively extended. Compared to designs using a single lead screw, this composite structure significantly improves the stability of the footrest during sliding, effectively avoiding the lack of sliding stability often associated with a lead screw alone. 4. The structural design is simple, eliminating the need for complex processes and numerous components, significantly reducing production costs while maintaining performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the present invention in a stored state.

[0018] Figure 2 It is a structural diagram of the extension mechanism.

[0019] Figure 3 It is a structural diagram of the folding mechanism.

[0020] Figure 4 It is a structural diagram of the locking mechanism.

[0021] Figure 5 This is a diagram of the supporting sheet metal when it is fully extended from the seat.

[0022] Figure 6 It is a schematic diagram of the supporting sheet metal after folding.

[0023] Figure 7 This is a diagram of the present invention in the retracted state under the entire chair.

[0024] Figure 8 Open the state diagram under the whole chair for the present invention. DETAILED DESCRIPTION

[0025] like Figure 1 —As shown in Figure 8, a footrest mechanism is hidden at the bottom of the seat. There is a gap between the bottom of the seat and the vehicle body floor. The footrest mechanism is arranged in the gap and fixed to the seat. The footrest mechanism mainly consists of an extension mechanism, a folding mechanism and a locking mechanism.

[0026] The extension mechanism includes a drive mechanism A, a bridge bracket 11, and a mounting bracket 1 for securing to the seat bottom. Drive mechanism A is fixed to mounting bracket 1, and bridge bracket 11 is connected to mounting bracket 1 for forward and backward sliding. The folding mechanism includes a support sheet metal 15 and a flip assembly B. Support sheet metal 15 is mounted to bridge bracket 11 via flip assembly B and is kept flat.

[0027] The driving mechanism A is connected to the supporting sheet metal 15 and can drive it to move backward together with the bridge bracket 11. When the supporting sheet metal 15 is fully extended from the seat, the locking mechanism can realize the backward sliding locking of the bridge bracket 11. At this time, the driving mechanism A continues to work and can drive the supporting sheet metal 15 to fold upward, so that it forms a support state with high front and low back.

[0028] That is, the driving mechanism A can drive the supporting sheet metal 15 and the bridge bracket 11 to switch between the storage state and the open state.

[0029] Ideally, the seat bottom is equipped with a slide mechanism. This mechanism typically includes two left and right slide assemblies, with one side of the slide assembly comprising an upper slide and a lower slide that slide relative to each other. The seat bottom is secured to the two upper slides via two upper slide brackets, with the mounting bracket 1 secured between the two upper slides. This design facilitates installation of the footrest mechanism and ensures a secure connection between the footrest and the seat. During the seat's sliding motion, the footrest mechanism remains stable and functions properly, providing reliable foot support for rear passengers. It will not move up or down with front seat height adjustment, nor will its opening angle be affected by adjustments to the front seatback angle.

[0030] Preferably, the mounting bracket 1 includes two longitudinal brackets 101 and a transverse bracket 102 connected between the front ends of the two longitudinal brackets 101. The cross-section of the two longitudinal brackets 101 is U-shaped, and the inner side walls thereof are provided with outer drawer rails 2 extending forward and backward. The two ends of the bridge bracket 11 respectively cooperate with the two outer drawer rails 2 through the inner drawer rails 3, thereby slidingly connecting to the two longitudinal brackets 101. The outer side walls of the two longitudinal brackets 101 are provided with mounting holes for driving bolts. The drawer rail sliding connection method can ensure that the bridge bracket 11 slides back and forth stably and smoothly between the longitudinal brackets 101, reducing jamming and shaking during the sliding process. The outer side walls of the two longitudinal brackets 101 are provided with mounting holes for driving bolts. Through these mounting holes, the mounting bracket 1 can be conveniently fixed to a suitable position on the bottom of the seat, and the installation process is simple and easy to operate.

[0031] Preferably, the drive mechanism A includes an extension motor 4, a fixed bracket 6 and an extension hinge mechanism 7, the fixed bracket 6 is connected between the two longitudinal brackets 101 and is located on the rear side of the transverse bracket 102, the extension motor 4 is a screw motor, which is fixed to the transverse bracket 102, and its screw extends backward, and the screw is threadedly sleeved with an extension bracket 5, and the extension hinge mechanism 7 includes two first connecting rods 701 cross-hinged in the middle, two second connecting rods 702 cross-hinged in the middle, and two third connecting rods 703 cross-hinged at the rear end, the front ends of the two first connecting rods 701 are limited to sliding left and right on the fixed bracket 6, and can rotate horizontally along the fixed bracket 6 (specifically, two left and right extending rods are relatively arranged on the fixed bracket 6). The front ends of the two first links 701 are slidably connected to the two slide grooves 601 by step bolts or rivets, the front ends of the two second links 702 are hinged to the rear ends of the two first links 701, and the front ends of the two third links 703 are hinged to the rear ends of the two second links 702. The extension bracket 5 is horizontally rotatably connected to the two first links 701 at the cross hinge of the two first links 701, and the support sheet metal 15 is horizontally rotatably connected to the two third links 703 at the cross hinge of the two third links 703 through the flip assembly B. When the extension motor 4 is working, it can drive the extension bracket 5 to move forward and backward, thereby driving the extension hinge mechanism 7 to perform forward and backward telescopic movement, and then drive the support sheet metal 15 and the bridge bracket 11 to move forward and backward together. The multi-link hinge mechanism design allows the footrest mechanism to have a large range of motion. Through the relative rotation and sliding between the links, it can meet the requirement of extending the support sheet metal 15 from the bottom of the seat to the appropriate position.

[0032] Preferably, the flip assembly B includes two lower end supporting swing arms 13 and two upper end supporting swing arms 12, as well as a rotating swing arm 14. The two ends of the bridge bracket 11 extend forward to form an extension section. The two extension sections are provided with first guide grooves 8 extending forward and backward on the left and right sides. The lower ends of the two upper end supporting swing arms 12 are slidably limited in the two first guide grooves 8 through the swing arm rotating shaft 16 and can rotate along the same. The upper ends of the two upper end supporting swing arms 12 are hinged to the two sides of the bottom front end of the supporting sheet metal 15, and the lower ends of the two lower end supporting swing arms 13 are hinged to the two sides of the rear end of the bridge bracket 11 through the connection rear bracket 10. The two lower end supporting swing arms 13 The upper ends of the support sheet metal 15 are welded to either side of the rear end of the bottom surface. The upper ends of the rotating swing arms 14 are hinged to the middle of the bottom surface of the support sheet metal 15 via stepped bolts or rivets. The lower ends of the rotating swing arms 14 are vertically hinged to the front connecting bracket 9, which is horizontally connected to the front connecting bracket 9 at the intersection of the two third connecting rods 703. When the bridge bracket 11 slides backward and locks, and the extension motor 4 drives the extension hinge mechanism 7 to continue to extend backward, it can drive the rotating swing arms 14 to flip upward, thereby driving the support sheet metal 15, the lower support swing arms 13, and the upper support swing arms 12 to move together, thereby achieving the folding of the support sheet metal 15. This design allows for flexible adjustment of the folding angle of the support sheet metal 15. In actual use, the folding angle of the support sheet metal 15 can be precisely controlled according to the needs of rear passengers and the adjustment of the seats, providing passengers with a more personalized comfort experience. The opening angle of the support sheet metal 15 can range from 0 to 40 degrees, and the specific design can be adjusted based on actual needs.

[0033] Preferably, the locking mechanism includes a locking shaft 18, a locking guide bracket 19 and two sliding locking sheet metals 17 arranged side by side on the left and right. The two sliding locking sheet metals 17 are respectively located on the inner sides of the corresponding side extension sections of the bridge bracket 11. The front ends of the two sliding locking plates 17 are respectively fixed to the two ends of the fixed bracket 15. The middle parts of the two sliding locking sheet metals 17 are respectively fixed to the longitudinal brackets 101 on the corresponding sides through fixed ears 20. The two sliding locking sheet metals 17 are relatively provided with second guide grooves 21 extending front and back. The front end of the first guide groove 21 and the rear end of the second guide groove 8 are both provided with upwardly extending locking sections. The locking guide bracket 19 is horizontally rotatably connected to the two second connecting rods 702 at the cross hinge point. The locking guide bracket 19 is provided with an oblique guide groove with a high front and a low rear. The locking shaft 18 passes through the horizontal direction. It is arranged in each of the first guide groove 21, the second guide groove 8 and the oblique guide groove; when the supporting sheet metal 15 is in a horizontal state, the locking shaft 18 is located at the rear end of the first guide groove 21, and at the front end of the second guide groove 8 and the lowest end of the oblique guide groove. When the bridge bracket 11 moves backward, the locking shaft 18 can move forward relative to the first guide groove 21, and at the same time move backward relative to the second guide groove 8. When the supporting sheet metal 15 is fully extended out of the seat, the locking shaft 18 just slides to the rear end of the second guide groove 8 and the front end of the first guide groove 21 to realize the backward sliding locking of the bridge bracket 11. At this time, the extension motor 4 drives the extension hinge mechanism 7 to continue to extend backward, and the locking shaft 18 can slide obliquely upward relative to the lowest end of the oblique guide groove, thereby sliding into the locking section of the first guide groove 21 and the second guide groove 8.

[0034] On the one hand, the design of the oblique guide groove ensures that after the bridge bracket 11 slides and is locked, the locking shaft 18 will not interfere with the continued backward movement of the extending hinge mechanism 7, and the extending hinge mechanism 7 can move backward relative to the locking shaft 18 (before the bridge bracket 11 slides and is locked, the extending hinge mechanism 7 can drive the locking guide bracket 19 to move forward and backward when it extends and retracts forward and backward, thereby driving the locking shaft 18 to move forward and backward).

[0035] On the other hand, the design of the oblique guide groove enables the locking shaft 18 to slide into the locking section of the first guide groove 21 and the second guide groove 8, so as to achieve interlocking of the bridge bracket 11 and the sliding locking sheet metal 17, thereby enhancing the impact resistance of the locking mechanism.

[0036] Preferably, the longitudinal brackets 101 are integrally formed with the outer drawer rails 2, the bridge brackets 11 are integrally formed with the inner drawer rails 3, and the inner drawer rails 3 are located outside the corresponding side extensions. The fixed brackets 6 are connected between the bottom surfaces of the two longitudinal brackets 101, and the fixed lugs 20 are fixed to the bottom surfaces of the corresponding side longitudinal brackets 101. This integral design makes the entire structure more robust, capable of withstanding greater forces and vibrations, and improves the reliability and durability of the footrest mechanism. The fixed brackets 6 are connected between the bottom surfaces of the two longitudinal brackets 101, and the fixed lugs 20 are fixed to the bottom surfaces of the corresponding side longitudinal brackets 101. That is, the fixed brackets 6, fixed lugs 20, and the extension hinge mechanism 7 are staggered to prevent them from interfering with the movement of the extension hinge mechanism 7.

[0037] Preferably, the front bracket 9 and the rear bracket 10 are both in an "L" shape, the lower end of the rotating swing arm 14 is vertically hinged to the vertical section of the front bracket 9, the horizontal section of the front bracket 9 is horizontally rotatably connected to it at the cross hinge of the two third connecting rods 703, the horizontal section of the rear bracket 10 is welded to the bridge bracket 11, and the lower end of the lower end supporting swing arm 13 is vertically hinged to the vertical section of the corresponding side rear bracket 10. The overall structure is simple and easy to install.

Claims

1. A footrest mechanism hidden under a seat, wherein there is a gap between the seat bottom and the vehicle body floor, characterized in that: The footrest mechanism is arranged in the gap and fixed on the seat. The footrest mechanism includes an extension mechanism, a folding mechanism and a locking mechanism. The extension mechanism includes a driving mechanism (A), a bridge bracket (11) and a mounting bracket (1) fixed to the bottom of the seat. The driving mechanism (A) is fixed on the mounting bracket (1). The bridge bracket (11) is connected to the mounting bracket (1) in a forward and backward sliding manner. The folding mechanism includes a supporting sheet metal (15) and a flip assembly (B). The supporting sheet metal (15) is installed on the bridge bracket (11) through the flip assembly (B) and is in a flat state. The driving mechanism (A) is connected to the supporting sheet metal (15) and can drive it to move backward together with the bridge bracket (11). When the supporting sheet metal (15) is fully extended from the seat, the locking mechanism can realize the backward sliding locking of the bridge bracket (11). At this time, the driving mechanism (A) continues to work and can drive the supporting sheet metal (15) to fold upward, so that it forms a supporting state with a high front and a low back.

2. The footrest mechanism hidden at the bottom of the seat according to claim 1, characterized in that: The seat bottom is equipped with a slide rail mechanism, which generally includes two left and right slide rail assemblies. The single-side slide rail assembly includes an upper slide rail and a lower slide rail that can slide relative to each other. The seat bottom is fixed to the two upper slide rails through two upper slide rail brackets, and the mounting bracket (1) is fixed between the two upper slide rails.

3. The footrest mechanism hidden at the bottom of the seat according to claim 2, characterized in that: The mounting bracket (1) comprises two longitudinal brackets (101) and a transverse bracket (102) connected between the front ends of the two longitudinal brackets (101). The cross-sections of the two longitudinal brackets (101) are U-shaped, and the inner side walls thereof are provided with outer drawer rails (2) extending forward and backward. The two ends of the bridge bracket (11) respectively cooperate with the two outer drawer rails (2) through the inner drawer rails (3), thereby being connected to the two longitudinal brackets (101) by sliding forward and backward. The outer side walls of the two longitudinal brackets (101) are provided with mounting holes for driving bolts.

4. The footrest mechanism hidden at the bottom of the seat according to claim 3, characterized in that: The driving mechanism (A) comprises an extension motor (4), a fixed bracket (6) and an extension hinge mechanism (7), wherein the fixed bracket (6) is connected between the two longitudinal brackets (101) and is located at the rear side of the transverse bracket (102), the extension motor (4) is a screw motor, which is fixed on the transverse bracket (102), and its screw extends backward, and the extension bracket (5) is threadedly sleeved on the screw, and the extension hinge mechanism (7) comprises two first connecting rods (701) cross-hinged in the middle, two second connecting rods (702) cross-hinged in the middle, and two third connecting rods (703) cross-hinged at the rear end, the front ends of the two first connecting rods (701) are limited to sliding left and right on the fixed bracket (6), and can rotate horizontally along the fixed bracket (6) (specifically, two left and right connecting rods are relatively arranged on the fixed bracket (6)). The extended slide (601), the front ends of the two first connecting rods (701) are slidably connected to the two slide grooves (601) one by one through step bolts or rivets, the front ends of the two second connecting rods (702) are hinged to the rear ends of the two first connecting rods (701), and the front ends of the two third connecting rods (703) are hinged to the rear ends of the two second connecting rods (702). The extension bracket (5) is horizontally rotatably connected to the two first connecting rods (701) at the cross hinge, and the support sheet metal (15) is horizontally rotatably connected to the two third connecting rods (703) at the cross hinge. When the extension motor (4) is working, it can drive the extension bracket (5) to move forward and backward, thereby driving the extension hinge mechanism (7) to perform forward and backward telescopic movement, and then driving the support sheet metal (15) and the bridge bracket (11) to move forward and backward together.

5. The footrest mechanism hidden at the bottom of the seat according to claim 4, characterized in that: The flip assembly (B) includes two lower end support swing arms (13) and two upper end support swing arms (12), as well as a rotating swing arm (14). The two ends of the bridge bracket (11) extend forward to form an extension section. The two extension sections are provided with first guide grooves (8) extending forward and backward in a relative manner on the left and right sides. The lower ends of the two upper end support swing arms (12) are slidably limited in the two first guide grooves (8) through the swing arm rotating shaft (16) and can rotate along the two first guide grooves. The upper ends of the two upper end support swing arms (12) are hinged to the two sides of the bottom front end of the supporting sheet metal (15). The lower ends of the two lower end support swing arms (13) are hinged to the two sides of the rear end of the bridge bracket (11) through the connecting rear bracket (10). The two lower end support swing arms (13) The upper ends of the rotating swing arm (14) are welded to both sides of the rear end of the bottom surface of the supporting sheet metal (15), and the upper end of the rotating swing arm (14) is hinged to the middle of the bottom surface of the supporting sheet metal (15) through step bolts or rivets. The lower end of the rotating swing arm (14) is vertically hinged to the connecting front bracket (9), and the connecting front bracket (9) is horizontally connected to it at the cross hinge of the two third connecting rods (703). When the bridge bracket (11) slides backward and is locked, and the extension motor (4) drives the extension hinge mechanism (7) to continue to extend backward, it can drive the rotating swing arm (14) to flip upward, thereby driving the supporting sheet metal (15), the lower end supporting swing arm (13) and the upper end supporting swing arm (12) to move together to realize the folding of the supporting sheet metal (15).

6. The footrest mechanism hidden at the bottom of the seat according to claim 5, characterized in that: The locking mechanism includes a locking shaft (18), a locking guide bracket (19) and two sliding locking sheet metals (17) arranged side by side on the left and right. The two sliding locking sheet metals (17) are respectively located on the inner side of the corresponding side extension section of the bridge bracket (11). The front ends of the two sliding locking plates (17) are respectively fixed to the two ends of the fixed bracket (15). The middle parts of the two sliding locking sheet metals (17) are respectively fixed to the longitudinal bracket (101) on the corresponding side through fixed ears (20). The two sliding locking sheet metals (17) are respectively provided with second guide grooves (21) extending forward and backward. The front end of the first guide groove (21) and the rear end of the second guide groove (8) are both provided with upwardly extending locking sections. The locking guide bracket (19) is horizontally connected to the two second connecting rods (702) at the cross hinge of the two second connecting rods (702). The locking guide bracket (19) is provided with an oblique guide groove with a front higher and a rear lower. The locking shaft (18) is horizontally passed through In each of the first guide groove (21), the second guide groove (8) and the oblique guide groove; when the supporting sheet metal (15) is in a horizontal state, the locking shaft (18) is located at the rear end of the first guide groove (21), the front end of the second guide groove (8) and the lowest end of the oblique guide groove; when the bridge bracket (11) moves backward, the locking shaft (18) can move forward relative to the first guide groove (21) and move backward relative to the second guide groove (8); when the supporting sheet metal (15) is fully extended from the seat, the locking shaft (18) just slides to the rear end of the second guide groove (8) and the front end of the first guide groove (21) to achieve backward sliding locking of the bridge bracket (11); at this time, the extension motor (4) drives the extension hinge mechanism (7) to continue to extend backward, and the locking shaft (18) can slide obliquely upward relative to the lowest end of the oblique guide groove, thereby sliding into the locking section of the first guide groove (21) and the second guide groove (8).

7. The footrest mechanism hidden in the seat bottom according to claim 6, characterized in that: The longitudinal bracket (101) and the outer drawer rail (2) are integrally formed, the bridge bracket (11) and the inner drawer rail (3) are integrally formed, and the inner drawer rail (3) is located outside the corresponding side extension section, the fixed bracket (6) is connected between the bottom surfaces of the two longitudinal brackets (101), and the fixed lug (20) is fixed to the bottom surface of the corresponding side longitudinal bracket (101).

8. The footrest mechanism hidden in the seat bottom according to claim 5, characterized in that: The front connecting bracket (9) and the rear connecting bracket (10) are both L-shaped. The lower end of the rotating swing arm (14) is vertically hinged to the vertical section of the front connecting bracket (9). The horizontal section of the front connecting bracket (9) is horizontally rotatably connected to the two third connecting rods (703) at the cross hinge. The horizontal section of the rear connecting bracket (10) is welded to the bridge bracket (11). The lower end of the lower end supporting swing arm (13) is vertically hinged to the vertical section of the corresponding side rear connecting bracket (10).

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