Collar Screw Fastening with Integrated Clamping for Captive Pre-Assembly
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Solution Overview
Problem
Existing fastening devices for securing components to counter pieces using collar screws often require additional elastic elements for secure pre-assembly, increasing costs and complexity, and can be easily pulled out, leading to instability during transport and assembly.
Innovation Solution
A fastening device with a collar screw and a through hole featuring a radial stop projection and clamping projection, where the collar screw is clamped between the two, utilizing the material's inherent elasticity for secure fixation without additional elastic elements, allowing for robust and simplified production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastic element is provided in the through hole to guide the collar past the stop projection, then the collar screw can be pre-assembled in a captive manner, but the costs increase and the device complexity increases
Solution Approach 1:
The invention extracts and eliminates the elastic element from the through hole by providing a conical clamping projection that replaces its function. The collar screw is clamped axially between the stop projection and the conical clamping projection, achieving captive pre-assembly without requiring separate elastic components.
Solution Approach 2:
The clamping function previously performed by a separate elastic element is merged into the through hole structure itself via the conical clamping projection. This integration eliminates the need for additional components and simplifies the overall device structure.
2Reliability
If an elastic element is provided in the through hole to guide the collar past the stop projection, then the collar screw can be pre-assembled in a captive manner, but the pre-assembly time and effort increase
Solution Approach 1:
The elastic element is removed from the design, eliminating the need to pre-position it in the through hole during assembly. The collar screw can be directly inserted and clamped between the stop projection and conical clamping projection, significantly reducing pre-assembly steps and time.
3Ease of manufacture
If the collar screw is inserted into the through hole with axial support on the stop projection, then the collar screw can be pre-assembled, but it can be pulled out too easily in a disadvantageous manner
Solution Approach 1:
The stopping function and clamping function are merged into a single integrated structure. The collar screw is simultaneously supported axially by the stop projection and clamped by the conical clamping projection, achieving both pre-assembly capability and pull-out resistance through one design.
Solution Approach 2:
The conical clamping projection is pre-formed in the through hole to provide automatic clamping action. When the collar screw is inserted, the conical geometry automatically generates radial clamping force against the collar, securing it against pull-out forces before final assembly.
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 secure, cost-effective, and simplified method for pre-assembling the fastening device, preventing unwanted release and canting, while eliminating the need for additional elastic components, resulting in a robust and efficient assembly process.
Implementation Method 1
The elasticity of materials, which are usually used for the collar screw and/or the component, is thereby already sufficient for clamping the collar screw
Data Source
AI summary
A fastening device for securing a component to a counter piece may include a collar screw having a thread, a screw head, and a circumferential collar formed therebetween, and a fastening section in which a through hole is formed, a radial stop projection and a radial clamping projection being located inside the through hole, the clamping projection being located radially opposite and radially offset to the stop projection in an insertion direction. The collar screw may be inserted into the through hole in the insertion direction, and, in a pre-assembly state, the collar may be axially supported on the stop projection in a pull-out direction. In the pre-assembly state, the collar may be axially supported on the clamping projection in the insertion direction, and the collar screw may be clamped between the stop projection and the clamping projection.