Foldable chair leg and method of mounting the same

Abstract

This invention discloses a foldable chair leg and its installation method, including a base with several mounting slots. Each mounting slot contains a support leg that is inserted at a specific angle. Each mounting slot also contains a rotating groove. Each support leg includes a mounting portion and a rotating column located on the mounting portion. The rotating column rotatably engages with the rotating groove. The support leg is pre-formed from a first material and cooled to room temperature. The base is formed from a second material in a hot state. When the base is hot, the opening size of the rotating groove is larger than the front size of the mounting portion. After the support leg is inserted into the mounting slot at a set angle, the rotating groove retracts to a size that maintains a rotatable engagement with the rotating column. The support leg is axially confined within the base. The chair leg can easily switch between an unfolded use state and a folded storage and transportation state, significantly reducing packaging volume and greatly lowering logistics, transportation, and warehousing costs.

Description

Technical Field

[0001] This invention relates to the field of furniture accessories technology, and in particular to a foldable chair leg and its installation method. Background Technology

[0002] In modern office and home environments, office chairs with casters are widely used due to their mobility and comfort. These chairs typically feature a five- or more claw-shaped base to mount the casters and support the weight of the seat and the user. Currently, most office chair legs on the market are made using a one-piece casting or injection molding process. While this structure ensures sufficient mechanical strength, it also results in a bulky and fixed-shape product. In warehousing, logistics, and retail display, the one-piece structure occupies a significant amount of valuable vertical space, severely reducing the load capacity of a single container or shelf, thus significantly increasing warehousing and logistics costs and transportation complexity. To address this issue, some designs have begun to adopt detachable structures, attempting to achieve flat packaging by separating the legs from the central base to save space. However, existing common detachable solutions usually rely on standard fasteners such as bolts and screws for connection. Users must use specialized tools such as wrenches and screwdrivers for assembly or disassembly, making the process cumbersome, time-consuming, and resulting in a poor user experience. More importantly, some simple structures using a direct-insertion connection pose a significant safety hazard, as users can easily get their fingers pinched by the rapidly closing gaps when forcefully inserting the legs into the base holes. Furthermore, improperly designed connection structures can cause the chair to wobble under weight during use or take up extra space when stored due to a loose structure. Therefore, there is an urgent need in this field for a novel foldable chair leg structure that can significantly save storage and transportation space, allow users to perform tool-free, quick, and safe assembly and disassembly, and maintain stability and reliability in both use and storage states. Summary of the Invention

[0003] In order to solve at least some of the problems existing in the prior art, the present invention provides a foldable chair leg with low storage and transportation costs, tool-free disassembly and assembly, safety and reliability, and stable locking, as well as its installation method.

[0004] The present invention adopts the following technical solution: A foldable chair leg includes a base with several mounting slots. Each mounting slot contains a leg that is inserted at a specific angle. The mounting slot also contains a rotating groove. Each leg includes a mounting portion and a rotating column located on the mounting portion. The rotating column rotatably engages with the rotating groove. The leg is pre-formed from a first material and cooled to room temperature. The base is formed from a second material in a hot state. When the base is hot, the opening of the rotating groove is larger than the front of the mounting portion. After the leg is inserted into the mounting slot at a set angle, the rotating groove retracts to a size that maintains a rotatable engagement with the rotating column, and the leg is axially confined within the base. By adopting this technical solution, the leg is combined with the base through a thermal assembly process. The rotating column is tightly wrapped by the retracted rotating groove and allowed to rotate, achieving tool-free, quick, and stable installation of the leg, while axial confinement prevents it from falling off during use.

[0005] Preferably, the mounting portion is provided with a limiting protrusion. When the support leg rotates to a certain angle within the mounting groove, the edge of the limiting protrusion abuts against the first surface of the mounting groove. The front end of the limiting protrusion is a limiting stop, and the front end of the limiting stop has an inward recess. The first surface is an arc surface. By adopting the above technical solution, the cooperation between the limiting protrusion and the first surface provides a rotational fulcrum and a clear mechanical limit for the unfolding and folding of the support leg, ensuring that the folding trajectory is controllable and enhancing operational safety and stability.

[0006] Preferably, the foldable chair legs have a first state and a second state. In the first state, a plurality of the legs are unfolded, the mounting portion is located in the mounting groove, and the limiting abutment abuts against the first surface of the mounting groove. By adopting the above technical solution, in the unfolded use state, the limiting abutment abuts tightly against the first surface, forming a reliable lock, ensuring that the chair legs are stable and do not wobble when bearing load, thus meeting the strength requirements.

[0007] Preferably, in the second state, the legs are folded up, and the mounting portion is at least partially located within the mounting groove and abuts against the first surface of the mounting groove. By adopting the above technical solution, in the folded storage and transportation state, the legs fit snugly against the inner wall of the mounting groove, resulting in a neat and compact shape, minimizing the overall packaging volume and facilitating storage and transportation.

[0008] Preferably, the lower end of the mounting groove is provided with an inclined groove. During the transition from the first state to the second state, the limiting abutment rotates from inside the mounting groove into the inclined groove, and in the second state, the limiting protrusion surface is in contact with the inclined groove surface. The upper end of the mounting groove is a mounting opening, which is connected to the rotating groove, and the side of the mounting opening closest to the rotating groove is an inclined surface. By adopting the above technical solution: the inclined groove provides a smooth transition path for the movement of the limiting abutment, making the folding process smooth; the inclined surface of the mounting opening guides the support leg to slide in at the correct angle, simplifying the installation operation.

[0009] Preferably, the mounting portion includes a first arc-shaped portion and a second arc-shaped portion located on the upper and lower surfaces of the limiting protrusion, respectively, and the base is provided with a clearance groove to accommodate the rotation of the first arc-shaped portion. By adopting the above technical solution, the cooperation between the first arc-shaped portion and the clearance groove ensures that the support leg has sufficient space during rotation, avoids interference with the base, and makes the folding action smoother.

[0010] Preferably, the angle at which the support leg is inserted into the mounting groove is 60°±2°, and the upper end of the mounting groove is provided with an inclined surface to guide the support leg to slide in. By adopting the above technical solution—setting a specific installation angle and cooperating with the guide inclined surface—the support leg can be accurately and easily aligned and inserted into the mounting groove during hot assembly, thereby improving assembly accuracy and efficiency.

[0011] Preferably, the base is made of polyamide 66 + 30% glass fiber or polyamide 6 + 30% glass fiber, and the legs are made of polypropylene + 20% talc, modified polypropylene, or high-density polyethylene. By adopting the above technical solution, the feasibility of the thermal assembly process is ensured by using a specific combination of engineering plastics with different coefficients of thermal expansion; at the same time, the selected material combination takes into account the strength and rigidity of the base as well as the toughness and wear resistance of the legs, meeting the mechanical performance requirements of the product.

[0012] A method for installing foldable chair legs, applicable to any of the foldable chair legs described above, further includes the following steps: S1: Provide a pre-formed support leg, the support leg including a mounting portion and a rotating column located on the mounting portion, and cool the support leg to room temperature; S2: Provide a base in a thermally expanded state, the base having a plurality of mounting slots, the mounting slots having a rotating slot, and the size of the rotating slot in the thermally expanded state being larger than the size of the rotating column; S3: Insert the support leg into the mounting groove at a set angle, so that the rotating column is placed in the rotating groove; S4: Cool the base, shrink the base so that the rotating groove and the rotating column form a rotating engagement, and the support leg is axially limited within the base.

[0013] By adopting the above technical solution, this method utilizes the thermal expansion and contraction characteristics of materials to achieve a tool-free, highly efficient, and permanent connection between the support legs and the base, simplifying the production process and reducing assembly costs.

[0014] Preferably, in step S3, during the process of inserting the support leg into the mounting groove at a set angle, the edge of the limiting protrusion abuts against the first surface of the mounting groove, and the surface of the rotating column abuts against the inner wall of the mounting opening; the support leg is moved downward at a set angle until the rotating column abuts against the intersection point B of the rotating groove and the inclined groove, and then the support leg is extended outward. At this time, the support leg will rotate around the edge of the limiting protrusion abutting against the first surface, and push the rotating column into the rotating groove through the reaction force until the limiting abutment at the end of the limiting protrusion abuts against the first surface, while the surface of the rotating column is in contact with the inner surface of the rotating groove and can rotate relative to the rotating groove. By adopting the above technical solution, this step describes in detail the technique of using the lever principle and geometric structure to complete the initial positioning and assembly of the support leg, ensuring that the rotating column can accurately fall into the predetermined position during the hot assembly process, laying the foundation for subsequent cooling and locking.

[0015] Preferably, the thermal expansion state of the base in S2 is obtained by injection molding the base and immediately performing the assembly operation in S3 after demolding. By adopting the above technical solution, the thermal expansion state brought about by the residual heat of the workpiece after injection molding is used for immediate assembly, eliminating the need for secondary heating of the base, which greatly simplifies the production process, saves energy and time costs, and optimizes the production process.

[0016] Compared with the prior art, the present invention has the following advantages: (1) Through the innovative folding structure design, the chair legs can be easily switched between the unfolded and folded states, which greatly reduces the packaging volume and significantly reduces logistics and warehousing costs; (2) The feet and the base are connected without tools through a hot-fitting process. Users can fold and unfold without any tools, which is simple, quick and easy and provides a good user experience. (3) The entire folding action is a pure rotational motion with a clear movement path and no sudden closing gap, which fundamentally eliminates the safety hazard of easy pinching of hands in the traditional plug-in structure. (4) By cooperating with the limiting protrusion, the limiting stop and the specific surface in the mounting groove, clear and reliable mechanical positioning and locking are provided for both the unfolded and retracted states, ensuring stable load-bearing during use and neat shape when stored. (5) By using specific engineering plastic combinations and thermal assembly methods, efficient and low-cost automated production is achieved while ensuring structural strength. Attached Figure Description

[0017] Figure 1 This is a structural diagram of the first state of the foldable chair legs.

[0018] Figure 2 for Figure 1 Another perspective structural diagram.

[0019] Figure 3 This is a structural diagram of the second state of the folding chair legs.

[0020] Figure 4 for Figure 3 Partial structural cross-sectional view.

[0021] Figure 5 This is a schematic diagram of the base structure.

[0022] Figure 6 This is a sectional view of the base.

[0023] Figure 7 This is a schematic diagram of the support structure.

[0024] Figure 8 for Figure 7 A magnified view of part A.

[0025] Figure 9 Installation process of the support legs Figure 1 .

[0026] Figure 10 Installation process of the support legs Figure 2 .

[0027] Figure 11 Installation process of the support legs Figure 3 .

[0028] In the figure, there are: base 1, mounting groove 1-1, rotating groove 1-2, first surface 1-3, inclined groove 1-4, mounting opening 1-5, clearance groove 1-6, support leg 2, mounting part 2-1, first arc-shaped part 2-1-1, second arc-shaped part 2-1-2, rotating column 2-2, limiting protrusion 2-3, limiting stop part 2-4, and concave part 2-4-1. Detailed Implementation

[0029] To facilitate understanding of the technical solution of the present invention, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments.

[0030] like Figures 1 to 8The foldable chair leg shown includes a base 1 with several mounting slots 1-1. Each mounting slot 1-1 contains a support leg 2 inserted at a specific angle. Each mounting slot 1-1 also contains a rotating slot 1-2. Each support leg 2 includes a mounting portion 2-1 and a rotating column 2-2 located on the mounting portion 2-1. The rotating column 2-2 rotatably engages with the rotating slot 1-2. The support leg 2 is pre-formed from a first material and cooled to room temperature. The base 1 is formed from a second material in a hot state. When the base 1 is hot, the opening size of the rotating slot 1-2 is larger than the front size of the mounting portion 2-1. After the support leg 2 is inserted into the mounting slot 1-1 at a set angle, the base 1 cools and contracts, causing the rotating slot 1-2 to contract to a size that maintains a rotatable engagement with the rotating column 2-2. The support leg 2 is axially confined within the base 1, meaning it cannot naturally detach from the base 1, and it can rotate relative to the base 1.

[0031] In this structure, utilizing the difference in thermal expansion coefficients of different engineering plastics, when the base 1 is in a high-temperature expansion state, the opening of its rotating groove 1-2 expands, allowing the mounting part 2-1 of the support leg 2 and the rotating column 2-2 to be easily inserted; after the base 1 cools and shrinks, the material of the rotating groove 1-2 retracts, tightly "hugging" the rotating column 2-2, forming a permanent rotating pair without the need for additional fasteners; at the same time, through this hot assembly process, the complex shaft-hole fit and axial limiting function are integrated, which not only has high assembly efficiency and low cost, but also reliable connection, completely avoiding the problems of easy loosening of traditional threaded connections or easy dislodgement of plug-in fits. For example, in some embodiments, the "hot state" refers to the state in which the base 1 has not completely cooled to room temperature after injection molding, and still maintains a relatively high temperature (such as slightly below the glass transition temperature of the material) and has good plasticity.

[0032] like Figure 7-8 As shown, the mounting part 2-1 is provided with a limiting protrusion 2-3. When the support leg 2 rotates to a certain angle in the mounting groove 1-1, the edge of the limiting protrusion 2-3 abuts against the first surface 1-3 of the mounting groove 1-1. The front end of the limiting protrusion 2-3 is a limiting stop 2-4, and the front end of the limiting stop 2-4 is provided with a concave part 2-4-1. The first surface 1-3 is an arc surface. In this structure, the arc-shaped first surface 1-3 and the edge of the limiting protrusion 2-3 form a rotation fulcrum, so that the folding movement of the support leg 2 becomes a pure rotation around the fulcrum, and the movement trajectory is clear and predictable. At the same time, the contact between the limiting stop 2-4 and the first surface 1-3 at a specific angle, as well as the slight elastic deformation or locking sensation that may be generated by the concave part 2-4-1, provides clear position feedback and mechanical locking for the unfolded state, ensuring stability during use.

[0033] like Figure 1-4As shown, the foldable chair legs have a first state and a second state. In the first state, several legs 2 are unfolded, the mounting part 2-1 is located within the mounting groove 1-1, and the limiting abutment 2-4 abuts against the first surface 1-3 of the mounting groove 1-1. In the second state, several legs 2 are folded, the mounting part 2-1 is at least partially located within the mounting groove 1-1, and the mounting part 2-1 abuts against the first surface 1-3 of the mounting groove 1-1. In this structure, the first state forms a stable mechanical triangular support through the rigid abutment of the limiting abutment 2-4 against the first surface 1-3, effectively resisting the vertical pressure and lateral torque from the seat; the second state, through the close contact between the legs 2 body and the inner wall of the mounting groove 1-1, neatly constrains the multiple legs 2 around the base 1, making the overall structure compact and fixed in shape, facilitating stacking and packaging; switching between the two states only requires a simple rotation operation, and both have clear physical limits, providing an intuitive and safe user experience.

[0034] like Figure 5-6 As shown, the lower end of the mounting groove 1-1 is provided with an inclined groove 1-4. During the transition from the first state to the second state, the limiting abutment 2-4 rotates from the mounting groove 1-1 into the inclined groove 1-4, and in the second state, the surface of the limiting protrusion 2-3 is in contact with the surface of the inclined groove 1-4. The upper end of the mounting groove 1-1 is a mounting opening 1-5, which is connected to the rotating groove 1-2, and the side of the mounting opening 1-5 closest to the rotating groove 1-2 is an inclined surface. In this structure, the inclined groove 1-4 serves as a guide and receiving structure, providing a smooth transition track for the limiting abutment 2-4 to move from the working position (against the first surface 1-3) to the storage position, avoiding motion interference and making the folding process smooth and effortless. At the same time, in the second state, the complete contact between the limiting protrusion 2-3 and the inclined groove 1-4 further enhances the tightness and torsional resistance of the folded state. The inclined surface of the mounting opening 1-5 automatically guides the support leg 2 to slide in at the correct angle during initial assembly, reducing the assembly difficulty and the requirements for operational precision.

[0035] like Figure 7-8 As shown, the mounting part 2-1 includes a first arc-shaped part 2-1-1 and a second arc-shaped part 2-1-2 located on the upper and lower surfaces of the limiting protrusion 2-3, respectively. The base 1 is provided with a clearance groove 1-6 to accommodate the rotation of the first arc-shaped part 2-1-1. In this structure, the cooperation between the first arc-shaped part 2-1-1 and the clearance groove 1-6 provides the necessary clearance space for the support leg 2 during large-angle rotation from unfolding to retraction, preventing structural interference between the support leg 2 and the base 1 body. At the same time, the cooperation between the second arc-shaped part 2-1-2 and other contours within the mounting groove 1-1 together ensures the smoothness of movement and the controllability of posture of the support leg 2 during rotation.

[0036] like Figure 9-11As shown, the set angle for the support leg 2 to be inserted into the mounting groove 1-1 is 60°±2°, and the upper end of the mounting groove 1-1 is provided with an inclined surface to guide the support leg 2 to slide in. In this structure, the initial installation angle of approximately 60 degrees is an optimized value, which ensures that the rotating column 2-2 can be smoothly aligned and slid into the depth of the rotating groove 1-2 under the guidance of gravity and the inclined surface, while ensuring that the edge of the limiting protrusion 2-3 can just contact the first surface 1-3 to form the initial lever fulcrum. This precise angle design, combined with the assembly window period of thermal expansion, is the key to achieving smooth subsequent assembly and reliable function.

[0037] In some embodiments, the base 1 is made of polyamide 66 with 30% glass fiber (PA66-GF30) or polyamide 6 with 30% glass fiber (PA6-GF30), and the legs 2 are made of polypropylene with 20% talc (PP-T20), modified polypropylene (PP), or high-density polyethylene (HDPE). In this material combination, the PA66 or PA6 substrate has high strength and heat resistance, and the addition of glass fiber further improves rigidity, dimensional stability, and heat distortion temperature, ensuring the mechanical properties of the base 1 as the load-bearing core. Meanwhile, the PP or HDPE material has good toughness, wear resistance, and a low coefficient of friction, making it suitable for manufacturing the legs 2, which require frequent rotation. The significant difference in the coefficients of thermal expansion between the two materials is the physical basis for implementing the aforementioned thermal assembly process, enabling a reliable interference fit connection under controlled process temperatures.

[0038] In this embodiment, there are two ways to install the support leg 2 into the base 1.

[0039] In this embodiment, the material properties of the support leg 2 and the base 1 are as follows: A method for installing foldable chair legs, applicable to any of the foldable chair legs described above, further includes the following steps: S1: Provide a pre-formed support leg 2, the support leg 2 including a mounting part 2-1 and a rotating column 2-2 located on the mounting part 2-1, and cool the support leg 2 to room temperature; S2: Provide a base 1 in a thermally expanded state. The base 1 is provided with a plurality of mounting slots 1-1. The mounting slots 1-1 are provided with rotating slots 1-2. The size of the rotating slots 1-2 in the thermally expanded state is larger than the size of the rotating column 2-2. S3: Insert the support leg 2 into the mounting groove 1-1 at a set angle, so that the rotating column 2-2 is placed in the rotating groove 1-2; S4: Cool the base 1, and the base 1 shrinks to make the rotating groove 1-2 and the rotating column 2-2 form a rotating fit, and the support leg 2 is axially limited to the base 1.

[0040] This method utilizes the residual heat of the automated injection molding production line to assemble the base 1 immediately after it exits the mold, achieving seamless connection and high efficiency in the production process.

[0041] like Figure 9 As shown, in some embodiments, during S3, when the support leg 2 is inserted into the mounting groove 1-1 at a set angle, the edge of the limiting protrusion 2-3 abuts against the first surface 1-3 of the mounting groove 1-1, and the surface of the rotating column 2-2 abuts against the inner wall of the mounting opening 1-5; as Figure 10 As shown, move the support leg 2 downwards at a set angle until the rotating column 2-2 abuts against point B, the intersection of the rotating groove 1-2 and the inclined groove 1-4; as shown Figure 11 As shown, the support leg 2 is then extended outwards. At this point, the support leg 2 rotates around the edge of the limiting protrusion 2-3 that abuts against the first surface 1-3, and through the reaction force, pushes the rotating column 2-2 into the rotating groove 1-2 until the limiting abutment 2-4 at the end of the limiting protrusion 2-3 abuts against the first surface 1-3. Simultaneously, the surface of the rotating column 2-2 adheres to the inner surface of the rotating groove 1-2 and can rotate relative to the rotating groove 1-2. In this step, the lever principle is cleverly used. The contact point between the limiting protrusion 2-3 and the first surface 1-3 is used as the fulcrum, and the torque generated by pressing down the tail end of the support leg 2 (the roller mounting end) "pryes" the rotating column 2-2 into the correct mating position. This action not only completes the final positioning of the assembly but also ensures that the rotating column 2-2 and the rotating groove 1-2 are in a good mating relationship before the hot assembly cools and locks, improving the quality consistency of the final product.

[0042] Referring to the accompanying drawings, the working principle of this invention is as follows: During the manufacturing stage, utilizing the thermal expansion characteristics of the base material, the room-temperature support leg is inserted into the hot base mounting groove at a specific angle. After cooling, the rotating groove contracts and hugs the rotating column, forming a permanent rotating shaft connection. When in use, the user simply moves the support leg by hand, causing it to rotate around the rotating column, with the limiting protrusion sliding along the arc surface of the first surface within the mounting groove. When the support leg rotates to the fully extended position, the limiting abutment rigidly abuts against the first surface, achieving self-locking and ensuring stable load-bearing capacity. When folding, the support leg is rotated in the opposite direction, causing the limiting abutment to slide away from the first surface into the inclined groove until the support leg body fits against the inner wall of the mounting groove, achieving a compact folded state. Throughout the entire process, the movement is solely rotational, with no sudden closing gaps, ensuring safety and reliability. Therefore, this invention, through the synergistic effect of a tool-free, heat-assembly connection and a rotating folding limiting structure, creatively achieves a foldable chair leg that is "tool-free, quick to assemble, safely folds, stable in its state, and space-saving."

[0043] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention shall be determined by the scope defined in the claims. Any improvements and modifications made by those skilled in the art without departing from the spirit and scope of the present invention shall also be considered as within the scope of protection of the present invention.

Claims

1. A foldable chair leg, characterized in that, The system includes a base (1), which has several mounting slots (1-1). Each mounting slot (1-1) has a support leg (2) that is inserted at a specific angle. Each mounting slot (1-1) has a rotating slot (1-2). Each support leg (2) includes a mounting part (2-1) and a rotating column (2-2) located on the mounting part (2-1). The rotating column (2-2) is rotatably engaged with the rotating slot (1-2). The support leg (2) is pre-formed from a first material and cooled to room temperature. The base (1) is formed from a second material in a hot state. When the base (1) is hot, the opening size of the rotating slot (1-2) is larger than the size of the front part of the mounting part (2-1). After the support leg (2) is inserted into the mounting slot (1-1) at a set angle, the rotating slot (1-2) shrinks to a size that maintains a rotatable engagement with the rotating column (2-2). The support leg (2) is axially confined within the base (1).

2. The foldable chair leg according to claim 1, characterized in that, The mounting part (2-1) is provided with a limiting protrusion (2-3). When the support leg (2) rotates to a certain angle in the mounting groove (1-1), the edge of the limiting protrusion (2-3) abuts against the first surface (1-3) of the mounting groove (1-1). The front end of the limiting protrusion (2-3) is a limiting abutment (2-4), and the front end of the limiting abutment (2-4) is provided with an indentation (2-4-1). The first surface (1-3) is an arc surface.

3. The foldable chair leg according to claim 2, characterized in that, The foldable chair legs have a first state and a second state. In the first state, a plurality of the legs (2) are in an unfolded state, the mounting part (2-1) is located in the mounting groove (1-1) and the limiting abutment (2-4) abuts against the first surface (1-3) of the mounting groove (1-1).

4. The foldable chair leg according to claim 3, characterized in that, In the second state, a plurality of the legs (2) are in a retracted state, and the mounting part (2-1) is at least partially located in the mounting groove (1-1) and the mounting part (2-1) abuts against the first surface (1-3) of the mounting groove (1-1).

5. The foldable chair leg according to claim 4, characterized in that, The lower end of the mounting groove (1-1) is provided with an inclined groove (1-4). During the transition from the first state to the second state, the limiting abutment (2-4) rotates from the mounting groove (1-1) to the inclined groove (1-4), and in the second state, the surface of the limiting protrusion (2-3) is attached to the surface of the inclined groove (1-4). The upper end of the mounting groove (1-1) is a mounting port (1-5), which is connected to the rotating groove (1-2), and the side of the mounting port (1-5) near the rotating groove (1-2) is an inclined surface.

6. The foldable chair leg according to claim 2, characterized in that, The mounting part (2-1) includes a first arc-shaped part (2-1-1) and a second arc-shaped part (2-1-2) located on the upper and lower surfaces of the limiting protrusion (2-3), respectively. The base (1) is provided with a relief groove (1-6) to accommodate the rotation of the first arc-shaped part (2-1-1).

7. The foldable chair leg according to claim 2, characterized in that, The set angle for the support leg (2) to be inserted into the mounting groove (1-1) is 60°±2°, and the upper end of the mounting groove (1-1) is provided with an inclined surface to guide the support leg (2) to slide in.

8. The foldable chair leg according to claim 2, characterized in that, The base (1) is made of polyamide 66 + 30% glass fiber or polyamide 6 + 30% glass fiber, and the legs (2) are made of polypropylene + 20% talc or modified polypropylene or high-density polyethylene.

9. A method for installing foldable chair legs, characterized in that, The foldable chair legs applicable to any one of claims 1-8 further include the following steps: S1: Provide a pre-formed support leg (2), the support leg (2) including a mounting part (2-1) and a rotating column (2-2) located on the mounting part (2-1), and cool the support leg (2) to room temperature; S2: Provide a base (1) in a thermally expanded state, the base (1) having a plurality of mounting grooves (1-1), the mounting grooves (1-1) having a rotating groove (1-2) inside, and the size of the rotating groove (1-2) in the thermally expanded state being larger than the size of the rotating column (2-2); S3: Insert the support leg (2) into the mounting groove (1-1) at a set angle, so that the rotating column (2-2) is placed in the rotating groove (1-2); S4: Cool the base (1), shrink the base (1) to form a rotational fit between the rotating groove (1-2) and the rotating column (2-2), and limit the support leg (2) axially within the base (1).

10. The method for installing foldable chair legs according to claim 9, characterized in that, In step S3, during the process of inserting the support leg (2) into the mounting groove (1-1) at a set angle, the edge of the limiting protrusion (2-3) abuts against the first surface (1-3) of the mounting groove (1-1) and the surface of the rotating column (2-2) abuts against the inner wall of the mounting opening (1-5); the support leg (2) is moved downward at a set angle until the rotating column (2-2) abuts against the intersection point B of the rotating groove (1-2) and the inclined groove (1-4), and then the support leg (2) is extended outward. At this time, the support leg (2) will rotate around the edge of the limiting protrusion (2-3) abutting against the first surface (1-3) and push the rotating column (2-2) into the rotating groove (1-2) through the reaction force until the limiting abutment (2-4) at the end of the limiting protrusion (2-3) abuts against the first surface (1-3), and at the same time, the surface of the rotating column (2-2) is attached to the inner surface of the rotating groove (1-2) and can rotate relative to the rotating groove (1-2).

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