Plastic Door Check Ultrasonic Welding
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Solution Overview
Problem
Current plastic door check devices for vehicles rely on steel fasteners for assembly, which add weight, require corrosion plating, and increase installation time and cost due to the need for mechanical fastening.
Innovation Solution
A door check device using a plastic housing assembly with non-mechanical fastening methods, such as ultrasonic welding, to secure the components together, eliminating the need for steel fasteners and reducing assembly time and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel fasteners are used to secure the housing components, then the structural strength and reliability are improved, but the device weight increases and corrosion protection requirements arise
Solution Approach 1:
The patent replaces the mechanical fastening system (steel fasteners, rivets, or screws) with an ultrasonic welding system. The ultrasonic welding process uses high-frequency vibration to melt and fuse the plastic housing components together, eliminating the need for separate mechanical fasteners. This substitution reduces device weight while maintaining structural integrity through the fused joint.
Solution Approach 2:
The patent changes the physical state of the plastic material during assembly. By applying ultrasonic energy, the plastic material transitions from a solid state to a melted state at the joint interface, then solidifies to form a strong fusion bond. This parameter change enables joining without mechanical fasteners, reducing weight while achieving reliable structural connection.
2Reliability
If steel fasteners with corrosion plating are used, then corrosion resistance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces the multi-step corrosion protection process (metal fastener fabrication, plating, coating) with a single-step ultrasonic welding process that joins plastic components directly. This eliminates all corrosion-related manufacturing steps while maintaining reliability through the inherent corrosion resistance of plastic materials and the fused joint structure.
Solution Approach 2:
The patent uses plastic housing components that are inherently resistant to corrosion, replacing expensive metal fasteners that require ongoing corrosion protection. The plastic components can be molded with integrated fastening features that are fused together, eliminating the need for separate corrosion-resistant fastener components and their associated plating processes.
3Reliability
If mechanical fastening methods are used, then assembly reliability is improved, but processing time and installation cost increase
Solution Approach 1:
The patent replaces the multi-step mechanical fastening process (positioning fasteners, inserting them, tightening them) with a single-step ultrasonic welding process. The ultrasonic welding head applies vibration and pressure to fuse the housing components together in one operation, dramatically reducing assembly time while maintaining joint reliability through the fused connection.
Solution Approach 2:
The patent incorporates alignment features and engagement structures into the molded plastic housing components before assembly. These pre-formed features guide the components into proper alignment during the ultrasonic welding process, ensuring reliable joints without requiring complex positioning or adjustment steps during assembly. The components are prepared in advance with integrated fastening geometries that simplify the final joining 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 provides a lightweight, cost-effective door check device with reduced processing time and no need for corrosion plating, while maintaining the functionality of maintaining the vehicle door position through biasing structures and detents.
Implementation Method 1
The plastic housing member and the plastic cover are secured by fusion of the materials to each other in the area of contact between the first and the second engagement structures
Data Source
AI summary
A door check device for installation between a vehicle body and a vehicle door that swings in opposing opening and closing directions relative to the vehicle body is provided. The door check device comprises a housing assembly and an elongated link member. The housing assembly comprises a first mounting structure, and a plastic housing member containing a biasing structure, a first link member engaging structure and a second link member engaging structure therein. The plastic housing member has a first engagement structure. The first mounting structure includes a plastic cover that has a second engagement structure that is constructed and arranged to engage with the first engagement structure to form an area of contact therebetween. The plastic housing member and the plastic cover are secured by fusion of the materials to each other in the area of contact between the first and the second engagement structures.