A chassis structure that can be locked forward and backward.

Abstract

This invention discloses a chassis structure with lockable forward and backward tilting, including a chassis base bracket, a chassis fixing frame, and a rotating follower and a back frame connector disposed between the chassis base bracket and the chassis fixing frame. The two ends of the rotating follower are respectively connected to the front end of the chassis base bracket and the front end of the chassis fixing frame. The front end and middle part of the back frame connector are respectively connected to the rear end of the chassis base bracket and the rear end of the chassis fixing frame. A locking hook is connected through the center of the front end of the back frame connector, and the locking hook has a first position and a second position, which are connected by a position channel. A fixing pin is fixed in the chassis fixing frame. The fixing pin moves between the first position, the position channel, and the second position. When the fixing pin is in the first position, the back frame connector is in a forward tilting locked state; when the fixing pin is in the second position, the back frame connector is in a backward tilting locked state; when the fixing pin is in the position channel, the back frame connector is in an adjustable state.

Description

Technical Field

[0001] This invention relates to an office furniture accessory, and more particularly to a chassis structure that can be locked by tilting forward and backward. Background Technology

[0002] Currently, most chair chassis on the market lack both forward and backward tilt locking functions. They typically only have a separate backward tilt activation function, which cannot be locked after tilting back. Once the user's back is off the chair, the backrest automatically returns to its free state, requiring the user to continuously hold the backrest to maintain the tilted position. Alternatively, some chairs may have a backward tilt lock but lack a forward tilt lock, and even when the backward tilt lock is engaged, it cannot automatically adjust the forward tilt. In other words, the chair tilts backward as soon as the user leans back, and when the user no longer needs the tilted position, they must manually push the backrest frame back to the forward tilt position; it cannot automatically return and lock in the forward tilt position. Therefore, existing technology needs improvement and enhancement. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a chassis structure that can be locked to tilt forward and backward, so as to realize the locking of the chair back to tilt forward and backward and realize the automatic switching between the tilting forward and backward states.

[0004] The technical solution adopted by this invention to solve the above-mentioned technical problems is to provide a chassis structure that can be locked for both forward and backward tilting, including a chassis base bracket, a chassis fixing frame, and a rotating follower and a back frame connector disposed between the chassis base bracket and the chassis fixing frame. The front end of the rotating follower is connected to the front end of the chassis base bracket via a small rotating shaft, and the rear end of the rotating follower is connected to the front end of the chassis fixing frame via a small fixed shaft. The front end of the back frame connector is connected to the rear end of the chassis base bracket via a large rotating shaft, and the middle part of the back frame connector is connected to the rear end of the chassis fixing frame via a large fixed shaft. The core is connected by a locking hook through a large rotating shaft. The locking hook has locking positions, including a first position and a second position, which are connected by a position channel. A fixing pin is fixed in the chassis fixing frame. Rotating the locking hook causes the fixing pin to move between the first position, the position channel, and the second position. When the fixing pin is in the first position, the back frame connector is in a forward-tilting locked state. When the fixing pin is in the second position, the back frame connector is in a backward-tilting locked state. When the fixing pin is in the position channel, the back frame connector is in an adjustable state.

[0005] Furthermore, the locking hook is connected to the rear end of the chassis mounting bracket via a small tension spring; a sliding member is provided below the locking hook to abut against the rear side of the locking hook, the sliding member is disposed in the sliding groove of the chassis mounting bracket, and the rear end of the sliding member abuts against the rear wall of the sliding groove via a spring; a rotating member is provided on the front side of the sliding member, the rotating member abuts against the front end of the sliding member, the rotating member is connected to a back frame adjustment handle, and a handle through hole is provided in the middle of the chassis mounting bracket to allow the back frame adjustment handle to pass through; rotating the back frame adjustment handle causes the rotating member to push the sliding member to move, thereby causing the locking hook to rotate.

[0006] Furthermore, the top of the locking hook is provided with a first rotating hole that matches the large rotating shaft, and a connecting hole for connecting a small tension spring is provided below the first rotating hole. The first gear position and the second gear position are arranged sequentially below the connecting hole from top to bottom.

[0007] Furthermore, the rear end of the rotating component is provided with a first abutting surface and a second abutting surface, and the connection between the first abutting surface and the second abutting surface forms a first rounded corner. When the first abutting surface abuts against the front end of the sliding component, the sliding component moves to the front end of the sliding groove under the action of the spring force, and the fixing pin disengages from the locking position. When the second abutting surface abuts against the front end of the sliding component, the rotating component pushes the sliding component to the rear end of the sliding groove, and the fixing pin enters the locking position. The rotating component is provided with an insertion hole in the middle that cooperates with the back frame adjustment handle. The rotating component is provided with a fixing hole in the vertical direction that is perpendicular to and communicates with the insertion hole, and a connecting pin for fixing the back frame adjustment handle is provided in the fixing hole.

[0008] Furthermore, the front end of the slider is provided with an abutting inclined surface that abuts against the rotating component. The abutting inclined surface matches the first abutting surface. The front end of the abutting inclined surface forms a second rounded corner. The rear end of the slider is provided with a spring hole for accommodating the spring. The upper middle part of the slider is provided with an abutting cylinder that abuts against the locking hook.

[0009] Furthermore, the back frame connector includes a left side plate, a right side plate, and a base plate connecting the left side plate and the right side plate at the rear end. The front ends of the left side plate and the right side plate are provided with second rotating holes that match the large rotating shaft, and the second rotating holes are connected to the large rotating shaft. The middle of the left side plate and the right side plate is provided with a third rotating hole that matches the large fixed shaft, and the third rotating hole is connected to the large fixed shaft. The base plate is provided with mounting holes for connecting the back frame. The back frame connector rotates around the third rotating hole as a fulcrum. The distance from the rear end of the back frame connector to the third rotating hole is greater than the distance between the third rotating hole and the second rotating hole.

[0010] Furthermore, the front end of the rotary follower is provided with a fourth rotary hole that matches the small rotary shaft, and the fourth rotary hole is connected to the small rotary shaft; the rear end of the rotary follower is provided with a fifth rotary hole that matches the small fixed shaft, and the fifth rotary hole is connected to the small fixed shaft.

[0011] Furthermore, the chassis mounting bracket has a tapered hole at the bottom center for connecting the gas spring; the front end of the chassis mounting bracket has a sixth rotating hole that matches the small fixed shaft, and the sixth rotating hole is connected to the small fixed shaft; the middle part of the chassis mounting bracket has a pin fixing hole that matches the fixing pin, and the fixing pin is placed in the pin fixing hole; the rear end of the chassis mounting bracket has a seventh rotating hole that matches the large fixed shaft, and the seventh rotating hole is connected to the large fixed shaft.

[0012] Furthermore, the chassis support bracket is a rectangular frame, and the lower front side of the chassis support bracket is provided with an eighth rotation hole that matches the large rotation shaft and is connected to the large rotation shaft; the lower rear side of the chassis support bracket is provided with a ninth rotation hole that matches the small rotation shaft and is connected to the small rotation shaft; the top of the chassis support bracket is provided with a seat mounting hole for connecting the upper part of the seat.

[0013] Furthermore, the small fixed shaft and the large rotating shaft are connected by a large tension spring; the two ends of the large tension spring are respectively connected to the small fixed shaft and the large rotating shaft through tension spring connectors.

[0014] Compared with the prior art, the present invention has the following advantages: The forward and backward tilting lockable chassis structure provided by the present invention has a locking hook set on the large rotation axis. The position of the fixing pin in the locking hook is controlled by the rotation of the locking hook, thereby realizing the forward tilting lock, backward tilting lock and adjustment of the back frame connector; the rotation of the locking hook is realized by the back frame rotation handle, rotating part, sliding part, spring and tension spring, which makes the structure simple, stable and reliable; the back frame connector, rotating driven part, chassis fixing frame and chassis base support form a quadrilateral linkage structure. The back frame drives the back frame connector to rotate, and drives the rotating driven part to rotate through the large rotation axis and chassis base support; the chassis base support basically remains horizontal during the movement, ensuring the stability of the sitting posture; the overall structure is simple and reliable, the materials are environmentally friendly, the manufacturing is simple, the assembly and maintenance are convenient, and it is durable. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a chassis structure that can be locked to tilt forward and backward in an embodiment of the present invention;

[0016] Figure 2 This is an exploded view of the chassis structure that can be locked forward and backward in an embodiment of the present invention;

[0017] Figure 3This is a schematic diagram of the chassis structure with forward tilt and backward tilt lockable in an embodiment of the present invention, adjusted from a forward tilt lockable state to a backward tilt lockable state.

[0018] Figure 4 This is a schematic diagram of the locking hook in an embodiment of the present invention;

[0019] Figure 5 This is a schematic diagram of the rotating component in an embodiment of the present invention;

[0020] Figure 6 This is a schematic diagram of the slider in an embodiment of the present invention;

[0021] Figure 7 This is a schematic diagram of the back frame connector in an embodiment of the present invention;

[0022] Figure 8 This is a schematic diagram of a rotating follower in an embodiment of the present invention;

[0023] Figure 9 This is a schematic diagram of the chassis mounting frame in an embodiment of the present invention;

[0024] Figure 10 This is a schematic diagram of the chassis support bracket in an embodiment of the present invention.

[0025] In the picture:

[0026] 1. Back frame connector; 2. Small tension spring; 3. Large rotating shaft; 4. Locking hook; 5. Tension spring connector; 6. Large tension spring; 8. Rotary driven component; 9. Small rotating shaft; 10. Large fixed shaft; 11. Spring; 12. Sliding component; 13. Fixing pin; 14. Rotating component; 15. Back frame adjusting handle; 16. Connecting pin; 17. Small fixed shaft; 18. Chassis mounting bracket; 19. Chassis base bracket; 41. First rotating hole; 42. First gear position; 43. Second gear position; 44. Gear position channel; 45. Connecting hole; 81. Fourth rotating hole; 82. Fifth rotating hole; 83. 101. Reducing groove; 102. Second rotating hole; 103. Third rotating hole; 104. Mounting hole; 121. Spring hole; 122. Abutting bevel; 123. Abutting cylinder; 124. First rounded corner; 141. Insertion hole; 142. First abutting surface; 143. Second abutting surface; 144. Second rounded corner; 145. Fixing hole; 181. Sixth rotating hole; 182. Handle through hole; 183. Pin fixing hole; 184. Seventh rotating hole; 185. Tapered hole; 186. Cylindrical groove; 191. Ninth rotating hole; 192. Eighth rotating hole; 193. Seat mounting hole. Detailed Implementation

[0027] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0028] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may have other meanings besides indicating orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances.

[0029] Figure 1 This is a schematic diagram of a chassis structure that can be locked to tilt forward and backward in an embodiment of the present invention; Figure 2 This is an exploded view of the chassis structure that can be locked forward and backward in an embodiment of the present invention; Figure 3 This is a schematic diagram of the adjustable chassis structure with lockable tilt and rear tilt in an embodiment of the present invention; Figure 4 This is a schematic diagram of the locking hook structure in an embodiment of the present invention.

[0030] Please see Figures 1-4 The tilt-and-lockable chassis structure of this invention includes a chassis base bracket 19, a chassis fixing frame 18, and a rotating follower 8 and a back frame connector 1 disposed between the chassis base bracket 19 and the chassis fixing frame 18. The front end of the rotating follower 8 is connected to the front end of the chassis base bracket 19 via a small rotating shaft 9, and the rear end of the rotating follower 8 is connected to the front end of the chassis fixing frame 18 via a small fixed shaft 17. The front end of the back frame connector 1 is connected to the rear end of the chassis base bracket 19 via a large rotating shaft 3, and the middle part of the back frame connector 1 is connected to the rear end of the chassis fixing frame 18 via a large fixed shaft 10. The center of the front end of the back frame connector 1 is penetrated by the large rotating shaft 3. A locking hook 4 is connected to the chassis, and the locking hook 4 is provided with locking positions, including a first position 42 and a second position 43. The first position 42 and the second position 43 are connected by a position channel 44. A fixing pin 13 is fixed in the chassis fixing frame 18. Rotating the locking hook 4 causes the fixing pin 13 to move between the first position 42, the position channel 44 and the second position 43. When the fixing pin 13 is in the first position 42, the back frame connector 1 is in a forward tilting locked state. When the fixing pin 13 is in the second position 43, the back frame connector 1 is in a backward tilting locked state. When the fixing pin 13 is in the position channel 44, the back frame connector 1 is in an adjustable state.

[0031] Specifically, the locking hook 4 is connected to the rear side of the chassis mounting bracket 18 via a small tension spring 2; a sliding member 12 is provided below the locking hook 4 to abut against the rear side of the locking hook 4, and the sliding member 12 is located in the sliding groove of the chassis mounting bracket 18. The rear end of the sliding member 12 abuts against the rear wall of the sliding groove via a spring 11; a rotating member 14 is provided on the front side of the sliding member 12, and the rotating member 14 abuts against the front end of the sliding member 12. The rotating member 14 is connected to the back frame adjustment handle 15. The chassis mounting bracket 18 has a handle through hole 182 in the middle to allow the back frame adjustment handle 15 to pass through. Rotating the back frame adjustment handle 15 causes the rotating member 14 to push the sliding member 12 to move, thereby driving the locking hook 4 to rotate. The wire diameter of the small tension spring 2 is 0.8mm and the outer diameter is 7mm; the wire diameter of the spring 11 is 1mm and the outer diameter is 6mm; both are made of 65Mn material; the elastic force of the spring 11 and the tension of the small tension spring 2 are a pair of reaction forces, and the elastic force of the spring 11 must be 2-3 times greater than the tension of the small tension spring 2, otherwise it will affect the forward sliding of the sliding part 12.

[0032] When the back frame adjustment handle 15 drives the rotating part 14 to rotate clockwise to the lowest position, the sliding part 12 is forced to slide to the last position, and the spring 11 is compressed; at the same time, the small tension spring 2 pulls the locking hook 4 to rotate counterclockwise until it contacts the fixing pin 13 and locks into the locking position, at which point the locking hook 4 is locked by the fixing pin 13. The back frame connector 1 is locked in both forward and backward rotation. Conversely, when the back frame adjustment handle 15 drives the rotating part 14 to rotate counterclockwise to the highest position, the spring 11 drives the sliding part 12 to slide to the foremost position, and at the same time drives the locking hook 4 to rotate clockwise until it contacts the fixing pin 13 and stops; at this time, the fixing pin 13 is in the locking hook 4 position channel 44, and the locking hook 4 can rotate with the back frame connector 1 around the large fixed shaft 10 to achieve forward or backward tilting.

[0033] Preferably, the small fixed shaft 17 and the large rotating shaft 3 are connected by a large tension spring 6; both ends of the large tension spring 6 are connected to the small fixed shaft 17 and the large rotating shaft 3 respectively via tension spring connectors 5. The forward tilting force comes from the large tension spring 6, which is made of 4mm steel wire. The outer diameter of the large tension spring 6 is 20mm, and the material is 65Mn. After assembly, the large tension spring 6 retains a slight tension, and the tension of the large tension spring 6 will always force the back frame connector 1 to maintain a certain forward tilting force. The angle between the large tension spring 6 and the back frame connector 1 is generally around 135°. The tension of the large tension spring 6 prevents the back frame connector 1 from becoming loose and wobbly in a free state due to manufacturing errors and the influence of subsequent assembly processes.

[0034] Please continue reading Figure 4The forward and backward tilting lockable chassis structure of this embodiment of the invention has a locking hook 4 with a first rotating hole 41 at the upper end that matches the large rotating shaft 3. The diameter of the first rotating hole 41 is 10mm. At the lower rear end of the first rotating hole 41, there is a connecting hole 45 with a diameter of 3mm that matches the small tension spring 2. The lowest end has two locking positions, a first position 42 and a second position 43, and a position channel 44 connecting the two positions. The width of the first position 42, the second position 43, and the position channel 44 is approximately 6mm, which together form the movement space of the fixing pin 13. The locking hook 4 is welded from three steel plates. To ensure the strength of the back frame connector 1, the thickness of each of the three steel plates is 5mm, and they are made of No. 45 steel.

[0035] Please also see Figure 5 The tilting and locking chassis structure of this embodiment of the invention features a rotating component 14 with an 8mm diameter insertion hole 141 in the middle, which mates with the back frame adjustment handle 15. Perpendicular to the insertion hole 141, a 4mm diameter fixing hole 145 is provided, which mates with a connecting pin 16. The back frame adjustment handle 15 is fixed by inserting the connecting pin 16 into the fixing hole 145. The rear ends of the two rotating components 14 have intersecting first abutment surfaces 142 and second abutment surfaces 143, with an angle of approximately 60° between them. The intersection forms a second rounded corner 144 with a radius of 1.5mm. The first abutment surfaces 142 and 143 mate with the abutment slope 122 of the sliding component 12. The design of the two sloped surfaces at the front end of the rotating component 14 can be adjusted according to actual needs. The rotating component 14 is injection molded from nylon with 40% glass fiber, balancing wear resistance and strength.

[0036] Please also see Figure 6 In this embodiment of the invention, a tilt-and-lockable chassis structure is provided. The rear end of the slider 12 has a spring hole 121 at its center to accommodate the spring 11. The spring hole 121 is a blind hole with a diameter of 6.5 mm and a depth of approximately 19 mm. The front end of the slider 12 has an abutment slope 122 with an inclination angle of approximately 45°, used to engage with the first abutment surface 142 of the rotating member 14 to receive force. The foremost end of the abutment slope 122 has a first rounded corner 124, which transitions to the bottom plane. The radius of the first rounded corner 124 is approximately 2.5 mm, which is 1 to 2 mm larger than the radius of the second rounded corner 144 at the rear end of the rotating member 14. An abutment cylinder 123 with a diameter of 10 mm is provided at the upper middle part of the slider 12, perpendicular to the sliding direction of the slider 12. The surface of the abutting cylinder 123 directly contacts the rear end face of the locking hook 4. This is a direct line-to-surface contact, generating an interaction force. The sliding component 12 is injection molded from POM material to ensure wear resistance and strength.

[0037] Please also see Figure 7 The forward and backward tilting lockable chassis structure of this invention features a second rotating hole 101 with a diameter of 10mm at the front end of the back frame connector 1, which matches the large rotating shaft 3; and a third rotating hole 102 with a diameter of 10mm at the middle, which matches the large fixed shaft 10. The entire back frame connector 1 rotates around the third rotating hole 102 as the pivot point. Multiple mounting holes 103 are designed at the rear end of the back frame connector 1 for connection to the back frame. The diameter, number, and position of the mounting holes 103 can be designed according to actual needs. The distance from the rear end to the third rotating hole 102 should be approximately 1.5 times the distance between the second rotating hole 101 and the third rotating hole 102. If the distance is too short, a large backward tilting force is required; if it is too long, the backward tilting force is too small, affecting the backrest comfort. The back frame connector 1 is welded from three steel plates. To ensure the strength of the back frame connector 1, all three steel plates are 5mm thick and made of 45# steel.

[0038] Please also see Figure 8 The tilting and locking chassis structure of this invention features a fourth rotating hole 81 (8mm in diameter) at the front end of the rotating follower 8, which mates with a small rotating shaft 9, and a fifth rotating hole 82 at the rear end, which mates with a small fixed shaft 17. Both the fourth and fifth rotating holes 81 and 82 extend through the entire rotating follower 8 from left to right. The shape features of other positions can be adjusted according to actual needs. The rotating follower 8 is an injection-molded part with numerous grooves 83 in the middle. The rotating follower 8 is injection-molded from nylon with 30% glass fiber, ensuring both strength and durability.

[0039] Please also see Figure 9 The chassis structure of this invention, which allows for forward and backward tilting and locking, includes a chassis mounting bracket 18, which serves as a fixing component for supporting and securing other accessories. The chassis mounting bracket 18 has a tapered hole 185 in the middle for connection and fixing to the gas spring. The front end of the chassis mounting bracket 18 has a sixth rotating hole 181 (8mm in diameter) for connecting to the small fixed shaft 17, and a handle through hole 182 (8mm in diameter) in the middle for connecting to the back frame adjustment handle 15. Further back, there is a pin fixing hole 183 (5mm in diameter) for fixing the pin 13. The rearmost end has a seventh rotating hole 184 (10mm in diameter) for connecting to the large fixed shaft 10. Additionally, a sliding groove 187 is provided internally for the movement of the sliding component 12. Behind the sliding groove 187 is a cylindrical groove 186 for fixing the small tension spring 2. The end of the small tension spring 2 is hooked into the cylindrical groove 186 for fixation. The chassis mounting bracket 18 is made of nylon with 40% fiber injection molding. The inner side has many rubber reduction grooves and reinforcing ribs to ensure strength.

[0040] Please also see Figure 10The chassis structure of this invention, which allows for forward and backward tilting and locking, features a quadrilateral chassis support bracket 19. The rear end of the chassis support bracket 19 has a ninth rotation hole 191 with a diameter of 10 mm, which mates with the large rotation shaft 3. The front end of the chassis support bracket 19 has an eighth rotation hole 192 with a diameter of 8 mm, which mates with the small rotation shaft 9. The upper end of the chassis support bracket 19 also has a seat mounting hole 193 for mounting the upper part of the seat. The chassis support bracket 19 is injection molded from nylon with 30% glass fiber. Other features are not described in detail, as long as strength is ensured.

[0041] The large rotating shaft 3, small rotating shaft 9, large fixed shaft 10, small fixed shaft 17, large tension spring 6, small tension spring 2, spring 11, locking hook 4, fixing pin 13, back frame adjusting handle 15, and connecting pin 16 are all standard parts, readily available on the market, and inexpensive. All other parts are made of plastic and can be manufactured using ordinary injection molding, a simple process with good stability. All accessories require no post-processing such as electroplating, spraying, or welding. Both plastic and iron parts are directly recyclable, making them environmentally friendly.

[0042] In actual use, the tilt-forward and tilt-back lockable chassis structure of this invention, when the back frame adjustment handle 15 is rotated counterclockwise, causing the rotating component 14 to rotate a certain angle, the sliding component 12 slides forward under the force of the spring 11. The first abutting surface 142 of the rotating component 14 contacts the abutting inclined surface 122 of the sliding component 12, and the abutting cylinder 123 of the upper part of the sliding component 12 contacts the locking hook 4, forcing the locking hook 4 to rotate clockwise around the large rotating axis 3 a certain angle, after which the fixing pin 13 disengages from the locking position. At this time, the back frame connecting component 1 can rotate around the large fixed axis 10, thereby causing the large rotating axis 3 and the locking hook 4 to rotate together, the large tension spring 6 is stretched, and the small tension spring 2 is contracted. When the back frame connecting component 1 drives the locking hook 4 to rotate into place, and the fixing pin 13 is located at the end of the gear channel 44, the rotation stops. At this time, rotating the back frame adjustment handle 15 clockwise causes the rotating component 14 to rotate clockwise, forcing the sliding component 12 to slide backward, and the spring 11 is compressed. When the locking hook 4 is pulled by the small tension spring 2, it rotates counterclockwise and the fixing pin 13 is engaged in the locking position. That is, the locking hook 4 and the fixing pin 13 are locked, and the back frame connector 1 is locked and cannot tilt forward or backward.

[0043] In summary, the forward and backward tilting lockable chassis structure of this embodiment of the invention features a locking hook 4 on the large rotating shaft 3. The position of the fixing pin 13 within the locking hook 4 is controlled by the rotation of the locking hook 4, thereby achieving forward tilting lock, backward tilting lock, and adjustment of the back frame connector 1. The rotation of the locking hook 4 is achieved by the back frame rotating handle 15, rotating component 14, sliding component 12, spring 11, and tension spring. The structure is simple, stable, and reliable. The back frame connector 1, rotating driven component 8, chassis fixing frame 18, and chassis base bracket 19 form a quadrilateral linkage structure. The back frame drives the back frame connector 1 to rotate, which in turn drives the rotating driven component 8 to rotate via the large rotating shaft 3 and chassis base bracket 19. During movement, the chassis base bracket 19 remains essentially horizontal, ensuring the stability of the sitting posture. The overall structure is simple and reliable, the materials are environmentally friendly, the manufacturing process is simple, assembly and maintenance are convenient, and it is durable.

[0044] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be defined by the claims.

Claims

1. A chassis structure with lockable forward and backward tilting, characterized in that, The system includes a chassis base bracket, a chassis mounting bracket, and a rotating follower and a back frame connector disposed between the chassis base bracket and the chassis mounting bracket. The front end of the rotating follower is connected to the front end of the chassis base bracket via a small rotating shaft, and the rear end of the rotating follower is connected to the front end of the chassis mounting bracket via a small fixed shaft. The front end of the back frame connector is connected to the rear end of the chassis base bracket via a large rotating shaft, and the middle part of the back frame connector is connected to the rear end of the chassis mounting bracket via a large fixed shaft. A locking hook is connected through the center of the front end of the back frame connector via the large rotating shaft. The locking hook is equipped with locking positions, including a first position and a second position, which are connected by a position channel. A fixing pin is fixed in the chassis mounting bracket. Rotating the locking hook causes the fixing pin to move between the first position, the position channel, and the second position. When the fixing pin is in the first position, the back frame connector is in a forward-tilting locked state; when the fixing pin is in the second position, the back frame connector is in a backward-tilting locked state; when the fixing pin is in the position channel, the back frame connector is in an adjustable state. The locking hook is connected to the rear end of the chassis mounting bracket via a small tension spring. A sliding member is located below the locking hook and abuts against its rear side. This sliding member is positioned within a sliding groove in the chassis mounting bracket, and its rear end abuts against the rear wall of the sliding groove via a spring. A rotating member is located on the front side of the sliding member, abutting against its front end. The rotating member is connected to a back frame adjustment handle. The chassis mounting bracket has a handle through-hole in the middle, allowing the back frame adjustment handle to pass through. Rotating the back frame adjustment handle causes the rotating member to push the sliding member, thereby rotating the locking hook.

2. The tilt-and-lockable chassis structure as described in claim 1, characterized in that, The top of the locking hook is provided with a first rotating hole that matches the large rotating shaft, and a connecting hole for connecting a small tension spring is provided below the first rotating hole. The first gear position and the second gear position are arranged from top to bottom below the connecting hole.

3. The tilt-and-lockable chassis structure as described in claim 1, characterized in that, The rear end of the rotating component is provided with a first abutting surface and a second abutting surface, and the connection between the first abutting surface and the second abutting surface forms a first rounded corner. When the first abutting surface abuts against the front end of the sliding component, the sliding component moves to the front end of the sliding groove under the action of the spring force, and the fixing pin disengages from the locking position. When the second abutting surface abuts against the front end of the sliding component, the rotating component pushes the sliding component to the rear end of the sliding groove, and the fixing pin enters the locking position. The rotating component is provided with an insertion hole in the middle that cooperates with the back frame adjustment handle. The rotating component is provided with a fixing hole in the vertical direction that is perpendicular to and communicates with the insertion hole, and a connecting pin for fixing the back frame adjustment handle is provided in the fixing hole.

4. The tilt-and-lockable chassis structure as described in claim 3, characterized in that, The front end of the slider is provided with an abutting inclined surface that abuts against the rotating component. The abutting inclined surface matches the first abutting surface. The front end of the abutting inclined surface forms a second rounded corner. The rear end of the slider is provided with a spring hole for accommodating the spring. The upper middle part of the slider is provided with an abutting cylinder that abuts against the locking hook.

5. The tilt-and-lockable chassis structure as described in claim 1, characterized in that, The back frame connector includes a left side plate, a right side plate, and a base plate connecting the left side plate and the right side plate at the rear end. The front ends of the left side plate and the right side plate are provided with second rotating holes that match the large rotating shaft and are connected to the large rotating shaft. The middle of the left side plate and the right side plate is provided with a third rotating hole that matches the large fixed shaft and is connected to the large fixed shaft. The base plate is provided with mounting holes for connecting the back frame. The back frame connector rotates around the third rotating hole as a pivot point. The distance from the rear end of the back frame connector to the third rotating hole is greater than the distance between the third rotating hole and the second rotating hole.

6. The tilt-and-lockable chassis structure as described in claim 1, characterized in that, The front end of the rotary follower is provided with a fourth rotary hole that matches the small rotary shaft, and the fourth rotary hole is connected to the small rotary shaft; the rear end of the rotary follower is provided with a fifth rotary hole that matches the small fixed shaft, and the fifth rotary hole is connected to the small fixed shaft.

7. The tilt-and-lockable chassis structure as described in claim 1, characterized in that, The chassis mounting bracket has a tapered hole at the bottom center for connecting the gas spring; the front end of the chassis mounting bracket has a sixth rotating hole that matches the small fixed shaft, and the sixth rotating hole is connected to the small fixed shaft; the middle part of the chassis mounting bracket has a pin fixing hole that matches the fixing pin, and the fixing pin is set in the pin fixing hole; the rear end of the chassis mounting bracket has a seventh rotating hole that matches the large fixed shaft, and the seventh rotating hole is connected to the large fixed shaft.

8. The tilt-and-lockable chassis structure as described in claim 1, characterized in that, The chassis support bracket is a rectangular frame. The lower front side of the chassis support bracket is provided with an eighth rotation hole that matches the large rotation shaft and is connected to the large rotation shaft. The lower rear side of the chassis support bracket is provided with a ninth rotation hole that matches the small rotation shaft and is connected to the small rotation shaft. The top of the chassis support bracket is provided with a seat mounting hole for connecting the upper part of the seat.

9. The tilt-and-lockable chassis structure as described in claim 1, characterized in that, The small fixed shaft and the large rotating shaft are connected by a large tension spring; the two ends of the large tension spring are respectively connected to the small fixed shaft and the large rotating shaft through tension spring connectors.

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