What is the installation bracket installed under the car child seat fixing device?
The "lower mounting bracket" (also known as the lower support leg or support foot) in the car child seat fixation device is an important component at the bottom of the child safety seat for enhancing stability and preventing swaying, especially when using the ISOFIX fixation method.
Function and Purpose
Prevent swaying of the seat: After the ISOFIX latch connects the seat to the hard interface of the vehicle body, the lower mounting bracket further contacts the vehicle floor, forming three points of fixation (left and right ISOFIX + lower support leg), significantly improving stability.
Enhance collision safety: Especially when low-age children (typically for 0–4 years old, with a weight of ≤ 18kg) are installed in a reverse position, it can effectively reduce the forward displacement of the seat during sudden braking or collision.
Adapt to various vehicle models: Most lower support legs are adjustable in height to accommodate different floor angles and gaps of different vehicle models.
Installation Tips
Confirm vehicle compatibility: Ensure there is sufficient space below the rear seats of the vehicle to accommodate the bracket, and the floor is flat and free of debris.
Adjust height: Extend the bracket until it just contacts the vehicle floor to avoid being suspended or overly pressed.
Check stability: After installation, shake the seat left and right and front and back to ensure there is no obvious looseness (the standard requires the shaking to be no more than 2.5cm).
Common Combination Methods
ISOFIX + Lower Support Leg: Suitable for rearward-installed infant seats (such as 0–15kg).
ISOFIX + Pulling Strap: Suitable for forward-installed larger child seats (such as 9–36kg).
Note: Not all child seats are equipped with lower support legs. Whether to use them depends on the seat manual and the vehicle structure. If the vehicle floor has a central armrest, thick carpet, or inclination, the effect of the bracket contacting the floor may be affected. In such cases, consider the combination of ISOFIX + pulling strap.
The lower mounting bracket (usually referred to as the support foot or ISOFIX hard interface bracket) in the car child seat fixation device plays a crucial role in the installation of child safety seats, mainly in the following aspects:
Core Function
Enhance stability: By contacting the vehicle floor and providing support, it prevents the seat from swaying, tilting, or moving forward during a collision.
Improve rigid connection: Combined with the ISOFIX interface, it forms a "bottom two points + bottom support" or "bottom two points + top lacing" multi-point fixation system, significantly increasing the overall structural strength.
Reduce installation errors: Compared to the seat belt fixation method, the combination of ISOFIX + support foot is easier to operate and less prone to errors, meeting international safety standards.
Specific Function Description
Anti-reversal function
The support foot (also known as the support leg) extends downward from the bottom of the seat and contacts the vehicle floor, effectively preventing the seat from flipping forward during a collision, which is one of the important anti-reversal designs in the ISOFIX system.
Optimization of adaptability
For some vehicle models with a deeper ISOFIX interface or unclear guidance, adding a bracket with a guiding slot can help quickly and accurately align the interface, improving the installation experience.
Expansion of compatibility
For older models without an original ISOFIX interface, a universal ISOFIX bracket (such as Sibela, Kalseron, etc.) can be added for hard connection installation.
Safety performance verification
After correct installation, the support foot should be tightly in contact with the floor, without being suspended or loose; some seats are equipped with a horizontal detector, and the small ball must be in the green area to be considered qualified.
Installation Tips
Ensure the support foot is in full contact with the vehicle floor. If necessary, adjust the length or use anti-slip pads.
After installation, shake the seat by hand to confirm there is no obvious shaking (the ideal state is that the lateral movement does not exceed 1 inch). If the seat is equipped with both ISOFIX and LATCH, the ISOFIX + support legs combination should be used first, as it is the mainstream standard in Europe and has greater rigidity.
Note: Some child safety seats support using top straps instead of support legs as an anti-rollover method. The specific details should be referred to the product manual. If the vehicle does not have an ISOFIX interface, using the seat belt fixation method can be considered, but the safety is relatively lower.
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