Floating Clip Nut Fastener for Torque Transmission With Low Assembly Effort
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Solution Overview
Problem
Existing lightweight fasteners in vehicle and aviation industries face challenges with complex designs and high assembly effort due to the need for torque dissipation, which increases the complexity and cost of manufacturing and assembly.
Innovation Solution
A two-part lightweight fastener comprising a one-piece plastic clip body and clip nut with a cage-like structure allowing the nut to float, featuring a polygonal main body with concave side walls and lugs for secure torque transmission, reducing the need for additional torque arms and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lugs, pins or stop surfaces are provided to transmit torques from the clip nut to the clip body, then torque transmission is improved, but the complexity of the clip nut and assembly effort increase
Solution Approach 1:
The invention extracts and eliminates the unnecessary torque arms (lugs, pins, stop surfaces) from the clip nut design. The torque transmission function is achieved directly through the friction between the clip nut's bearing surface and the clamp mount, without requiring additional structural elements. This simplifies the clip nut to a basic nut shape while maintaining adequate torque transmission capability.
2Strength
If a fixed threaded sleeve is used to prevent nut turning, then torque transmission is improved, but the ease of operation during setting deteriorates due to lack of play
Solution Approach 1:
The invention introduces dynamic characteristics by allowing the clip nut to have rotational play within the clamp mount during the setting process. The nut can rotate freely until it engages with the threaded hole, providing operational ease. Once engaged, the friction between the bearing surface and clamp mount prevents further turning, ensuring adequate torque transmission. This dynamic behavior combines the benefits of both fixed and movable designs.
3Strength
If torque arms are provided for screwing the fastener into the clip nut, then torque transmission is improved, but the assembly effort increases
Solution Approach 1:
The invention removes the torque arms (lugs, pins, stop surfaces) from the design, reducing the number of components and assembly steps. The simplified clip nut structure requires fewer alignment and engagement operations during assembly, thereby increasing productivity while maintaining adequate torque transmission through friction-based prevention of nut turning.
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 design provides improved assembly, handling, and manufacturing characteristics by allowing for gentler force dissipation and optimized design with reduced complexity, enhancing the overall performance and efficiency of the fastening process.
Implementation Method 1
At least n side walls (with n >= 3) of the main body are curved in a concave manner... At least n inwardly directed wall elements of the cage, which are convexly curved inwards... The curvature of the side walls or wall elements follows the shape of conic sections
Data Source
Figure 1~3
Figure 4~6
AI summary
A lightweight fastener (10) comprises a one-piece plastic clip body (20) and a clip nut (40). The clip body has the basic shape of a clamp, with two opposing, longitudinally extending legs (22, 24) and a cage (28) in which the clip nut is floatingly mounted. The clip nut, in turn, has a nut base (42) which is essentially plate-shaped. A main body (44) is built upon the nut base, comprising a top surface (41) and a plurality of side walls (51, 51') extending between the nut base and the top surface. The side walls of the main body preferably have a convex curvature, and the cage has correspondingly concave walls. The dimensions are such that, when the lightweight fastener is used, the convex-concave surface pairs act as torque supports.