Composite Liftgate Tether Layout for Simpler Reinforcement Assembly
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Solution Overview
Problem
Current liftgate tether systems face challenges such as difficulty in assembly, high attachment point complexity, and potential damage from impacts due to the use of steel tethers, which are not well-suited for composite materials and do not allow for sufficient flexibility or strength preservation.
Innovation Solution
A tether system featuring over-molded retainer clips attached to composite material liftgates through apertures, with elongated fiber strands and slack to absorb forces, reducing the number of anchor points and enhancing strength by encapsulating fibers during injection molding to prevent breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel tethers are used to strengthen composite liftgates, then the liftgate strength is improved, but the assembly complexity and difficulty increase
Solution Approach 1:
The tether system is segmented into modular components: a flexible rope tether and separate retainer clips. This segmentation allows the tether to be attached at multiple discrete locations without requiring complex assembly procedures, as each retainer clip can be independently attached to the liftgate structure
Solution Approach 2:
The invention changes the material parameter from rigid steel to flexible rope material, and changes the attachment mechanism parameter from complex fastening to simple retainer clips. This parameter change maintains strength while dramatically simplifying assembly complexity
2Strength
If steel tethers are used with multiple attachment points, then the tether strength is improved, but the number of attachment points and assembly complexity increase
Solution Approach 1:
The retainer clip is designed as a universal attachment component that can be used at multiple locations along the liftgate structure. This multi-functional component reduces the variety of different attachment hardware needed, thereby reducing overall device complexity while maintaining multiple attachment points for strength
3Strength
If rigid steel tethers are used, then the tether strength is improved, but the susceptibility to impact damage increases
Solution Approach 1:
The invention changes the physical state parameter of the tether from rigid (steel) to flexible (rope material). This parameter change allows the tether to absorb impact forces through deformation and flexing rather than brittle failure, reducing susceptibility to impact damage while maintaining strength
Solution Approach 2:
The flexible rope material inherently provides cushioning against impact forces before damage can occur. The material's elasticity and ability to deform under load serve as a built-in protective mechanism that cushions against harmful impact effects
4Reliability
If traditional attachment methods are used, then the tether is secured to the liftgate, but the fiber integrity is compromised
Solution Approach 1:
The retainer clip is designed to clamp onto the flexible rope tether without rigid mechanical fastening that would cut or damage the fibers. The clip's design allows it to secure the tether through friction and geometry rather than compression that compromises fiber integrity
Solution Approach 2:
The invention uses a composite construction where the retainer clip (rigid material) attaches to the rope tether (flexible material) in a way that preserves the unique properties of each material. The attachment mechanism is designed to maintain the fiber structure of the rope while providing secure fastening
Data Source
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AI summary
A liftgate structure, comprising: a structural inner panel (10) with an outside surface (12) and an inner surface (14) having a lower perimeter surface area (16) extending across substantially the entire width of the liftgate structure, the structural inner panel (10) including a wiper motor housing recess (18) formed on the inner surface (14); a plurality of brackets (234, 236, 238) including a center bracket (234) and two side brackets (236, 238), the brackets being connected to the outside surface (12) of the structural inner panel (10); and three separate tethers (228, 230, 232) including first and second tethers (228, 230) extending between the center bracket (234) and a respective one of the side brackets (236, 238) and further including a third tether (232) extending between the side brackets (236, 238), wherein the first and second tethers (228, 230) have a different width than the third tether (232).