Automobile seat leg rest structure with interlock

Abstract

The application belongs to the technical field of automobile seat accessories, and relates to a car seat leg support structure with interlocking, which is composed of two plastic parts arranged in pairs. Both of the two plastic parts are C-shaped plastic parts, and are fixed in the car seat leg support body after assembly. A clamping unit is integrated on the plastic part I, and an embedded groove matched with the extension clamping structure of the plastic part II is formed on the side wall of the plastic part I. A limiting groove corresponding to the clamping unit is formed on the plastic part II, and an integral extension clamping structure is formed on the front end of the groove bottom. A screw column I is arranged on the top of the C-shaped plastic part of the plastic part I, and a ring-shaped reinforcing rib is arranged around the screw column I. A screw column II is also arranged on the top of the C-shaped plastic part of the plastic part II, and is connected with the car seat leg support body. Through the two-stage interlocking of the double C-shaped plastic parts and the integrated design of the pre-positioning pin, the part gap and axial movement are offset, the assembly warping deformation is eliminated, the appearance contour precision is improved, and the light weight, assembly efficiency and long-term use reliability are considered.

Description

Technical Field

[0001] This invention belongs to the field of automotive seat accessories technology, specifically relating to a plastic connection structure for automotive seat leg rests with double interlocking limits. Background Technology

[0002] Existing automotive seat leg rests use a single-layer snap-fit ​​plastic connection structure without secondary limiting and anti-detachment design. Parts are prone to flipping and falling off after external force or prolonged vibration. Furthermore, the lack of a pre-installed positioning structure makes alignment difficult during assembly, resulting in poor assembly consistency and low efficiency. Moreover, the absence of targeted reinforcing ribs and lightweight hollow integrated design leads to insufficient structural strength, making the structure prone to deformation under stress, further exacerbating issues like step differences, warping, and out-of-tolerance contours. Relying solely on a single-layer snap-fit ​​constraint cannot counteract axial movement caused by assembly gaps, resulting in a high rate of finished product defects. Meanwhile, existing conventional two-piece plastic mating structures only use simple snap-fit ​​connections without forming two-level interlocking protection, failing to simultaneously ensure assembly accuracy, structural strength, and long-term anti-detachment stability, making them unsuitable for the universal and high-precision assembly requirements of multi-platform seat leg rests.

[0003] In summary, existing plastic connection structures for automotive seat leg rests mostly employ a single snap-fit ​​mechanism, lacking a multi-layered interlocking and precise pre-positioning constraint system. This makes the parts prone to axial movement and misalignment after assembly, and over long-term use, the assembly surface is susceptible to wavy deformation. Consequently, the product's contour accuracy and surface flatness fail to meet the appearance precision requirements of OEMs. Therefore, there is an urgent need to develop a plastic connection structure for automotive seat leg rests with dual interlocking and limiting mechanisms to effectively solve these problems. Summary of the Invention

[0004] The purpose of this invention is to provide a plastic connection structure for car seat leg rests with double interlocking limits, in order to solve the problems of assembly movement, surface wave deformation, easy detachment, poor assembly accuracy, and insufficient strength of existing single plastic parts and snap-on leg rest structures. This invention uses a two-level interlocking design of double C-shaped plastic parts and an integrated design of pre-installed positioning pins to offset the gaps between parts and axial movement, prevent assembly warping deformation, improve the accuracy of the appearance contour, and at the same time take into account lightweight, assembly efficiency, and long-term reliability.

[0005] This invention is achieved through the following technical solution:

[0006] An interlocking car seat leg support structure includes mutually paired plastic parts I1 and II2, both of which are C-shaped plastic parts;

[0007] The plastic part I1 integrates multiple sets of snap-fit ​​units 11, and the snap-fit ​​unit 11 is provided with reinforcing ribs 12. The plastic part I1 is provided with screw posts I14 and embedded grooves 15.

[0008] The plastic part II2 has a limiting groove 21 that matches the snap-fit ​​unit 11. The bottom of the limiting groove 21 has an extension snap-fit ​​structure 22. The plastic part II2 has an integrally formed positioning pin 23 on the outside and a screw post 24.

[0009] During assembly, the snap-fit ​​unit 11 is embedded in the limiting groove 21 to form a primary interlock, the extended snap-fit ​​structure 22 is snapped into the embedded groove 15 to form a secondary anti-disengagement limit, and the positioning pin 23 is used for pre-positioning during assembly.

[0010] Furthermore, the plastic part I1 is provided with 6 sets of snap-fit ​​units 11, and the plastic part II2 is provided with 6 sets of limiting grooves 21.

[0011] Furthermore, the six sets of snap-fit ​​units 11 are arranged at intervals on the bottom of the inner wall of the first C-shaped plastic part.

[0012] Furthermore, the snap-fit ​​unit 11 has a hollow design inside.

[0013] Furthermore, the outer wall of the snap-fit ​​unit 11 is provided with reinforcing ribs 12.

[0014] Furthermore, the top of the first C-shaped plastic part is provided with three screw posts I14, and the screw posts I14 are surrounded by annular reinforcing ribs 13.

[0015] Furthermore, the sidewall of the plastic part I1 has an embedded groove 15 that matches the extension engagement structure 22 of the plastic part II2.

[0016] Furthermore, the top of the C-shaped plastic part II2 is provided with three screw posts II24 with reinforcing ribs.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. Dual-level, two-stage interlocking limit system completely solves the problems of movement and deformation. Utilizing a dual-interlocking system with a snap-fit ​​unit, a first-level constraint with a limit groove, an extended structure, and a second-level engagement with an embedded groove, it bidirectionally restricts the axial and radial displacement of parts, offsetting injection molding stage differences and assembly gaps. This effectively suppresses wavy warping of the assembly under stress, significantly improving the surface flatness and contour of the product, and significantly reducing the appearance defect rate. Compared to existing single C-shaped plastic parts patents, this system has an additional layer of reverse anti-detachment limit, preventing loosening or separation under long-term vehicle vibration, resulting in a longer service life.

[0019] 2. Pre-installed locating pins significantly improve assembly efficiency and consistency. The plastic part 2 features an integrated locating pin on its outer side, allowing for quick alignment with the locating holes during the initial assembly phase, eliminating the need for repeated manual calibration and shortening assembly time. During mass production, each product maintains a consistent assembly benchmark, eliminating manual alignment deviations and ensuring stable and controllable overall assembly dimensional accuracy. Existing patented C-shaped plastic parts lack a pre-installed locating structure, leading to difficulties in assembly alignment and significant dimensional fluctuations.

[0020] 3. Balancing lightweight design with structural strength to reduce costs. The snap-fit ​​unit adopts a hollow design to reduce weight, while multiple reinforcing ribs are arranged integrally inside and out. The screw posts and snap-fit ​​stress areas are also reinforced. While reducing the amount of raw materials used and injection molding costs, the snap-fit's resistance to bending and creep is improved, avoiding deformation under long-term stress.

[0021] 4. High integration and strong adaptability. The double C-shaped split assembly structure is suitable for the narrow internal space layout of various car seat leg rests. It can be adapted to multiple leg rest projects on the same platform without changing the main structure of the mold. It has strong versatility and can be applied in batches and in a standardized manner.

[0022] 5. Compared with existing patents, it has comprehensive advantages. This invention is a two-part paired, two-level interlocking structure, with the addition of a reverse anti-detachment secondary locking mechanism, pre-installed positioning pins, and a lightweight system with full-area reinforcing ribs. Its structural constraint capability, anti-detachment reliability, assembly precision, and appearance quality are all superior to existing single plastic part solutions, filling the gap in existing technology that lacks a dual interlocking, pre-installed positioning integrated leg support connection structure. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall exploded assembly of the present invention;

[0025] Figure 2 This is a 3D structural diagram of plastic part I;

[0026] Figure 3 This is a 3D structural diagram of plastic part II;

[0027] Figure 4 This is a cross-sectional interlocking structure diagram of the present invention after assembly.

[0028] In the figure, 1. Plastic part I; 11. Snap-fit ​​unit; 12. Reinforcing inner rib; 13. Reinforcing rib; 14. Screw post I; 15. Embedded groove; 2. Plastic part II; 21. Limiting groove; 22. Extended snap-fit ​​structure; 23. Locating pin; 24. Screw post II. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0030] Example 1

[0031] like Figures 1-4 As shown, an interlocking car seat leg support structure consists of a pair of plastic parts I1 and II2, which are fixed inside the main body of the car seat leg support after assembly.

[0032] The plastic part I1 is a first C-shaped plastic part integrally formed, on which 6 sets of snap-fit ​​units 11 are integrated. Specifically, the 6 sets of snap-fit ​​units 11 are arranged at intervals on the bottom of the inner wall of the first C-shaped plastic part. Each set of snap-fit ​​units 11 has reinforcing ribs 12 arranged on its outer wall to improve strength, and the interior adopts a hollow design to achieve lightweighting and weight reduction.

[0033] The top of the first C-shaped plastic part is provided with three screw posts I14, and the screw posts I14 are surrounded by annular reinforcing ribs 13 to strengthen the connection and improve the locking strength.

[0034] The side wall of the plastic part I1 has an embedded groove 15 that matches the extension engagement structure 22 of the plastic part II2.

[0035] The plastic part II2 is a second C-shaped plastic part that matches the first C-shaped plastic part. It has six sets of limiting grooves 21 corresponding one-to-one with the snap-fit ​​unit 11. Each limiting groove 21 has an integrally formed extending snap-fit ​​structure 22 extending forward from its bottom front end. An integrally formed positioning pin 23 protrudes outward from the outer side of the plastic part II2. The top of the second C-shaped plastic part also has three reinforcing screw posts II24, which connect to the main body of the car seat leg rest. The positioning pin structure on the outer side of the plastic part II2 enables precise positioning in the early stages of assembly, effectively improving the convenience and consistency of on-site assembly, and simultaneously improving the assembly accuracy of the assembly.

[0036] Assembly process:

[0037] Step 1, Pre-assembly and positioning: Align the outer positioning pin 23 of plastic part II2 with the preset positioning hole of the leg support body to complete the pre-alignment and fixation, and achieve a unified assembly benchmark;

[0038] Step 2, First-level interlock assembly: The 6 sets of snap-fit ​​units 11 of plastic part I1 are horizontally embedded into the 6 sets of limiting grooves 21 of plastic part II to complete the first layer of radial and axial limiting and form the first-level interlock constraint.

[0039] Step 3, Secondary anti-detachment locking: Press the plastic part I1 inward so that the extended locking structure 22 at the bottom of the groove of the plastic part II2 can be locked into the embedded groove 15 on the side wall of the plastic part I, forming a reverse lock. The two-level interlocking constraint is fully formed, and the parts cannot move back and forth, flip or fall off.

[0040] Step 4, Locking and Fixing: By passing screws through screw post I14 of plastic part I1 and II24 of plastic part II2 respectively, the entire double interlocking assembly is locked and fixed inside the leg support body, completing the assembly.

[0041] In this embodiment, the inner walls of the snap-fit ​​unit 11 and the limiting groove 21 are both injection molded with internal reinforcing ribs. The hollow structure reduces the weight by more than 12%, while the deformation resistance of the snap-fit ​​part is improved by 35%. After the two-stage interlocking is completed, the axial movement gap of the parts is completely eliminated, the finished leg support has no wave deformation, and the contour tolerance can be controlled within ±0.15mm. The pre-installation of the positioning pin can shorten the assembly time of a single set by 40%, and the dimensional dispersion of batch products is greatly reduced.

[0042] This invention constructs a dual anti-detachment limiting system to completely avoid the risk of parts falling off after assembly; the positioning pin enables precise pre-positioning in the early stage of assembly, significantly improving assembly efficiency and consistency, and ensuring the overall assembly accuracy of the assembly.

[0043] This structure is compatible with mainstream passenger car and commercial vehicle seat leg rest assemblies. Multiple leg rest products on the same platform can be directly used without the need to develop new molds, resulting in high adaptability and standardization.

[0044] In addition, the number of snap-fit ​​units 11 and limiting grooves 21 can be adjusted to 4-8 sets according to the leg rest size, the number of screw posts can be adapted to 2-4 sets, and 1-2 positioning pins 23 can be set to adapt to small and compact seat leg rests. The core structure of double interlocking, lightweight reinforcing ribs and pre-installed positioning remains unchanged, and it still has all the beneficial effects of anti-movement, anti-falling and high-precision assembly.

[0045] It will be understood by those skilled in the art that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A car seat leg rest structure with interlocking, characterized in that: Including plastic parts I (1) and II (2) that are paired with each other, both of which are C-shaped plastic parts; The plastic part I (1) integrates multiple sets of snap-fit ​​units (11), the snap-fit ​​unit (11) is provided with reinforcing ribs (12), and the plastic part I (1) is provided with screw post I (14) and embedded groove (15). The plastic part II (2) has a limiting groove (21) that matches the snap-fit ​​unit (11). The bottom of the limiting groove (21) has an extension snap-fit ​​structure (22). The plastic part II (2) has an integrally formed positioning pin (23) on the outside. The plastic part II (2) is provided with a screw post (24). During assembly, the snap-fit ​​unit (11) is embedded in the limiting groove (21) to form a first-level interlock, the extended snap-fit ​​structure (22) is snapped into the embedded groove (15) to form a second-level anti-disengagement limit, and the positioning pin (23) is used for pre-positioning during assembly.

2. The car seat leg support structure with interlocking according to claim 1, characterized in that: The plastic part I (1) is provided with 6 sets of snap-fit ​​units (11), and the plastic part II (2) is provided with 6 sets of limiting grooves (21).

3. The car seat leg support structure with interlocking according to claim 2, characterized in that: The six sets of snap-fit ​​units (11) are arranged at intervals at the bottom of the inner wall of the first C-shaped plastic part.

4. The car seat leg support structure with interlocking according to claim 3, characterized in that: The snap-fit ​​unit (11) has a hollow design inside.

5. The car seat leg rest structure with interlocking according to claim 4, characterized in that: The outer wall of the snap-fit ​​unit (11) is provided with reinforcing ribs (12).

6. The car seat leg rest structure with interlocking according to claim 5, characterized in that: The top of the first C-shaped plastic part is provided with three screw posts I (14), and the screw posts I (14) are surrounded by annular reinforcing ribs (13).

7. The car seat leg rest structure with interlocking according to claim 6, characterized in that: The side wall of the plastic part I (1) has an embedded groove (15) that matches the extension engagement structure (22) of the plastic part II (2).

8. The car seat leg rest structure with interlocking according to claim 7, characterized in that: The top of the C-shaped plastic part II (2) is provided with three screw posts II (24) with reinforcing ribs.

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