Sandwich Panel Fastener With Core-Penetrating Clamping Arms
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Solution Overview
Problem
Existing methods for connecting sandwich components, such as CFRP panels, face challenges including fixed connection points during manufacturing, shape and position tolerances, and limitations in adding or replacing fastening points, as well as weaknesses in adhesive connections under mechanical loads and temperature variations.
Innovation Solution
A two-part fastening device with actuable fixing arms that penetrate the core of a sandwich component, establishing a frictional connection through a clamping mechanism, allowing for flexible and secure attachment without adhesives, and enabling integration into the component during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If adhesive bonding is used to attach onserts to sandwich panels, then the connection avoids machining damage, but the bond strength is insufficient under transverse loads and temperature variations
Solution Approach 1:
The patent introduces a mechanical intermediary system (fastening device with clamping arms) that mediates between the sandwich panel and the component to be fastened. The clamping arms penetrate the core and clamp the onsert against the front surface, creating a mechanical force-fit connection that supplements and strengthens the adhesive bond, particularly under transverse loads and temperature variations where adhesive alone fails.
Solution Approach 2:
The fastening device combines multiple materials and connection methods: adhesive bonding for the onsert to the panel, mechanical clamping force from the clamping arms, and frictional engagement of the clamping arms with the core material. This composite approach creates a multi-mechanism connection that overcomes the limitations of any single method.
2Ease of manufacture
If connection points are fixed during manufacturing, then the manufacturing process is simplified, but flexibility for adding or replacing fastening points is lost
Solution Approach 1:
The fastening device is segmented into separate components: the onsert attached to the panel, the fastening device body, and the clamping arms. This segmentation allows the onsert to be positioned during manufacturing while the fastening device itself can be added or replaced later by simply attaching it to the onsert, providing flexibility without complicating the initial manufacturing process.
Solution Approach 2:
The fastening system transitions from a static adhesive bond to a dynamic mechanical connection. The clamping arms can be actuated to engage or disengage from the core material, allowing the fastening points to be added, removed, or repositioned after manufacturing, thus providing adaptability while maintaining manufacturing simplicity.
3Adaptability or versatility
If a mechanical fastening device with clamping arms is used, then adaptability and ease of installation are improved, but the device complexity increases
Solution Approach 1:
The clamping arms are designed to automatically engage with the core material when the fastening device is installed. The arms deflect during installation and then self-lock into position, clamping the onsert without requiring additional fastening steps or complex adjustment mechanisms. This self-service feature simplifies installation despite the apparent mechanical complexity.
Solution Approach 2:
The onsert acts as an intermediary element that simplifies the overall system. By attaching the onsert during manufacturing and then simply mounting the fastening device to the onsert, the complex clamping mechanism becomes a plug-and-play component, reducing the operational complexity despite its structural sophistication.
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 universally usable, cost-effective, and robust mechanical connection that can be easily integrated into sandwich components, overcoming the limitations of existing methods by ensuring stable and reliable fastening without adhesive weaknesses, and allowing for flexible positioning and replacement of fastening points.
Implementation Method 1
establishing a frictional connection through a clamping mechanism
Implementation Method 2
actuated fixing arms that can be moved from a mounting position to a fixing position
Implementation Method 3
an actuating element which can be inserted into an opening of the retaining element and which, in its position inserted into the retaining element, deflects at least one fixing arm into its fixing position
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention relates to a snap-together fastening device (1) for mounting by insertion into an opening (31) of a sandwich component (30), in particular a CFRP sandwich component consisting of two snap-together elements (10, 20), fixing arms (11) being arranged on an element (10) which can be actuated from a mounting position into a fixing position by the second element (20), said arms mechanically penetrating the foam (34) of the sandwich component such that a frictional connection with the sandwich component is produced.