Chisel Design for Vehicle Tear Line Manufacturing
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Solution Overview
Problem
Existing devices for creating a tear line in vehicle interior materials, such as thermoplastic cover sheets, face issues with material sticking due to inadequate release agent application, leading to impaired airbag deployment and adhesion problems.
Innovation Solution
A chisel with a progressively increasing point angle and convex cutting edge, used in high-frequency reciprocating motion, heats and displaces material to prevent sticking, allowing for precise cutting and reliable tearing without release agents, ensuring secure adhesion and smooth airbag deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a release agent is applied to prevent flank surfaces from sticking together, then sticking is prevented, but the release agent may get on the back of the cover film and prevent adhesion to backing foam
Solution Approach 1:
The patent removes the release agent from the system entirely. Instead of applying a release agent to prevent sticking, the chisel design inherently prevents sticking by heating and displacing the thermoplastic material, extracting the harmful substance (release agent) from the process while maintaining the desired function (preventing sticking).
Solution Approach 2:
The chisel performs multiple functions simultaneously: cutting, heating, and preventing sticking all through its reciprocating motion and geometric design. The tool serves itself by using its own movement and structure to achieve the desired effect without requiring external additives like release agents.
2Ease of manufacture
If an oscillating knife is used to create the tear line, then cutting is achieved, but the flank surfaces stick together immediately afterwards
Solution Approach 1:
The patent employs high-frequency reciprocating motion of the chisel to create mechanical vibration and heat in the material. This vibration-induced heating prevents the thermoplastic flanks from cooling and sticking together, while still achieving the cutting function through the reciprocating mechanical action.
Solution Approach 2:
The chisel design changes the thermal parameters of the material during cutting. Through friction and deformation heat generated by the reciprocating motion, the material temperature increases sufficiently to prevent sticking, transforming the thermal state of the cut surfaces.
3Manufacturing precision
If the chisel has a small point angle, then cutting precision is improved, but heat transfer to the material is insufficient
Solution Approach 1:
The chisel features an asymmetric point angle design where the angle increases progressively in the direction of the cutting edge. This asymmetric geometry optimizes both cutting precision and heat transfer by concentrating mechanical energy and friction heat at the cutting zone while maintaining control over the tear line profile.
Solution Approach 2:
The chisel incorporates a convex cutting edge that dynamically adapts to the material during reciprocating motion. This dynamic geometry maintains optimal contact pressure and heat generation throughout the cutting cycle, ensuring both precision and sufficient heat transfer.
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 ensures reliable, precise, and clean tear lines with improved cutting quality and durability, eliminating sticking issues and enabling secure adhesion, even in areas with rear foaming, while allowing for quick production of various tear line designs.
Implementation Method 1
Due to the high frequency of the reciprocating movement of the chisel, the material of the covering material located in the area of the tear line to be formed is heated to such an extent that the material is displaced from the area of the tear line
Data Source
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AI summary
The device has sections made of plastic, particularly an inside paneling material for vehicles, and a bearing (3), by which a cover material is supportable. The tool is formed by a chisel, if it is moving back and forth with a frequency from sixteen to seventy kilo hertz. An independent claim is also included for a method for manufacturing breaking line in back of cover material.