Keyhole Fastening Device Anti-Twist Locking Mechanism
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Solution Overview
Problem
Components fastened using the keyhole principle in the automotive industry often twist during installation, compromising their functionality if anti-twist protection is not provided, and existing solutions require components to be pre-inserted and secured before protection becomes effective.
Innovation Solution
A fastening device with a retaining element and a locking element that engages through the wider opening of a keyhole-shaped cutout, preventing the device from twisting by locking behind the wall, which can be manufactured as an injection-molded element with a flexible locking hook or one-way snap-in design, offering simple and cost-effective anti-twist protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the keyhole principle is used for fastening components, then cost is reduced and one-hand installation is enabled, but the component may twist during installation compromising functionality
Solution Approach 1:
The fastening device is divided into two functional elements: a retaining element that prevents twisting by covering the narrower opening edge, and a locking element that secures the device to the back side of the wall. This segmentation allows each element to specialize in one aspect of anti-twist protection, resolving the contradiction between simple keyhole fastening and reliable anti-twist protection.
Solution Approach 2:
The retaining element is designed to automatically cover the narrower opening edge as the fastening device is inserted into the keyhole-shaped cutout. This preliminary action of covering the opening occurs before the locking element is fully secured, providing immediate anti-twist protection from the start of installation, thus resolving the contradiction without requiring complex pre-installation steps.
2Reliability
If existing anti-twist protection is used, then twisting is prevented, but the component must be pre-inserted and secured before protection becomes effective
Solution Approach 1:
The retaining element is designed to automatically perform its anti-twist function as the fastening device is inserted into the keyhole-shaped cutout. The element's geometry causes it to naturally cover the narrower opening edge during insertion, providing self-service anti-twist protection without requiring separate pre-insertion or activation steps, thus resolving the contradiction between reliability and ease of operation.
3Reliability
If a locking element is added to prevent twisting, then anti-twist protection is improved, but manufacturing complexity increases
Solution Approach 1:
The locking element and retaining element are combined into a single integrated fastening device that can be manufactured as one piece using injection molding. This merging of functions into a single manufacturable unit resolves the contradiction by providing enhanced anti-twist protection through multiple elements while avoiding the manufacturing complexity of assembling separate components.
Solution Approach 2:
The fastening device utilizes the geometric parameters of the keyhole-shaped cutout (wider opening for insertion, narrower opening for retention) to enable both the locking element and retaining element to function effectively. By changing the parameters of the cutout shape rather than adding complex mechanical features, the invention achieves improved anti-twist protection without significantly increasing manufacturing complexity.
Data Source
AI summary
A fastening device for fastening an element in a keyhole-shaped cutout in a wall includes a retaining element which in the fastened state of the fastening device is configured to rest against a front side of the wall, and to at least partially cover an edge of a narrower opening of the keyhole-shaped cutout. The fastening device also has a locking element which in the fastened state of the fastening device is configured to engage through a wider opening of the keyhole-shaped cutout, and to retain the fastening device from a back side of the wall.