Seat Belt Latch Plate with Two-Shot Elastomer Bumpers
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Solution Overview
Problem
The existing seat belt latch plate assembly generates unwanted noise when the seat belt is not in use and rests between the B-pillar and the car seat, due to the mass-induced side-to-side movement causing repetitive impact with the car seat.
Innovation Solution
The integration of noise-dissipating integral bumpers made from thermoplastic elastomers, molded into the latch plate cover using a two-shot injection molding process, which absorb and dissipate impact energy, preventing noise generation by ensuring the latch plate does not engage the car seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the latch plate assembly is positioned between the B-pillar and car seat for accessibility, then the passenger can easily find and grasp it, but the mass of the assembly induces significant side-to-side movement causing repetitive impact with the car seat and generating unwanted noise
Solution Approach 1:
The patent applies beforehand cushioning by integrating soft elastomeric bumpers directly into the latch plate cover structure. These bumpers are positioned at the edges of the latch plate cover that contact the car seat, providing cushioning before impact occurs. The elastomeric material absorbs impact energy and dissipates it as heat, preventing the repetitive clicking noise that would otherwise occur when the rigid latch plate assembly impacts the car seat during vehicle motion.
2Object-generated harmful factors
If soft noise-dissipating bumpers are added to the latch plate cover, then impact noise is absorbed and dissipated, but the structural integrity and rigidity of the latch plate may be compromised
Solution Approach 1:
The patent applies local quality by making the latch plate cover a composite structure with different material properties in different locations. The main body of the latch plate cover is made from rigid plastic to maintain structural integrity and latching function. The edges that contact the car seat are made from soft elastomeric material to absorb impact noise. This localized differentiation of material properties allows the structure to be rigid where needed and compliant where needed, resolving the contradiction between strength and noise reduction.
Solution Approach 2:
The patent applies composite materials by creating a multi-material latch plate cover through two-shot injection molding. The first shot creates a rigid plastic base structure for strength and form. The second shot adds elastomeric material to specific surfaces that contact the car seat. This composite construction combines the advantages of both rigid and flexible materials in a single integrated component, achieving both structural integrity and noise dissipation.
3Object-generated harmful factors
If multiple materials are used for the latch plate cover to achieve noise dissipation and structural integrity, then both functions are fulfilled, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies merging by combining the rigid latch plate cover structure and the soft noise-dissipating bumpers into a single integrated component. Through two-shot injection molding, both the rigid plastic body and the elastomeric edge protectors are molded together in one manufacturing process. This eliminates the need for separate manufacturing and assembly steps for attaching bumpers to the latch plate cover, reducing manufacturing complexity despite using multiple materials. The process integrates material application, shaping, and bonding in a single automated operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces noise by using soft, hemi-ellipsoid bumpers that absorb impact energy, maintaining durability and aesthetic quality, ensuring the latch plate remains accessible without rattling.
Implementation Method 1
the mass of the seat belt latch plate assembly can induce significant side-to-side movement. This may cause a repetitive impact with the side of the car seat which in turn generates an unwanted noise or rattle
Implementation Method 2
The bumpers are an effective passive countermeasure that performs the desired function without requiring the operator to take any specific action. Better noise reduction is ensured through the softness, thickness, number, position and shape of the bumpers which absorb and dissipate impact energy
Data Source
AI summary
A seat belt latch plate assembly includes a latch plate and a latch plate cover carried on the latch plate. That latch plate cover is made by means of a two-shot injection molding process and includes integral bumpers that are made from a soft, sound dissipating material and have an energy absorbing cross-sectional shape.