Dual-Molded Grab Handle Spacer for Sheet-Metal Tolerance Fit
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Solution Overview
Problem
Prior art grab handle spacers are too rigid and fail to accommodate sheet-metal variations, leading to increased insertion efforts during headliner clip installation due to misalignment of clip attachment surfaces.
Innovation Solution
A dual molded grab handle spacer with a one-piece body composed of thermoplastic material and thermoplastic elastomer, featuring articulating joints that allow bending and twisting to compensate for sheet-metal tolerance variations, reducing stress and insertion efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the grab handle spacer is made rigid with constant wall thickness, then structural strength is improved, but the ability to accommodate sheet-metal tolerance variations deteriorates
Solution Approach 1:
The grab handle spacer is divided into three distinct sections with different material properties: rigid end sections (first and second sections) for structural strength, and a flexible central section (third section) for accommodating tolerances. This segmentation allows each part to perform its specialized function optimally.
Solution Approach 2:
Different sections of the grab handle spacer have different material properties tailored to their specific functions. The end sections use rigid thermoplastic material for strength, while the central section uses flexible thermoplastic elastomer for adaptability. This local differentiation resolves the contradiction between overall strength and local flexibility.
2Ease of manufacture
If the grab handle spacer is made rigid, then manufacturing simplicity is improved, but clip insertion effort increases due to misalignment
Solution Approach 1:
The material parameter (rigidity) is changed in the central section by using thermoplastic elastomer instead of rigid thermoplastic. This parameter change allows the central section to flex and accommodate misalignment, reducing clip insertion effort while maintaining manufacturing simplicity through dual molding processes.
3Ease of manufacture
If constant wall thickness is used throughout, then manufacturing process is simplified, but stress concentration occurs during clip insertion
Solution Approach 1:
The grab handle spacer uses composite construction with two different materials: rigid thermoplastic for end sections and flexible thermoplastic elastomer for the central section. This composite approach allows the central section to absorb insertion stresses through flexibility while the rigid ends maintain structural integrity, reducing overall stress concentration.
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 dual molded design effectively reduces the stress on the grab handle spacer and simplifies the headliner clip insertion process by accommodating sheet-metal variations, thereby lowering the effort required for assembly.
Implementation Method 1
The central section includes two segments separated by a central opening so as to allow bending and twisting of the grab handle spacer to compensate for variations in the positions of sheet-metal attachment points
Data Source
AI summary
A grab handle spacer includes a first fastener receiver, a second fastener receiver and a first integral articulating joint. The grab handle spacer is dual molded from thermoplastic and thermoplastic elastomer materials which allow flexing, twisting and bending during the assembly process.