Propeller-Shaped Cable Grommet for Easier Harness Assembly
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Solution Overview
Problem
Current grommet production processes for automotive applications are complex, time-consuming, and require significant operator effort, making them inefficient and difficult to automate.
Innovation Solution
A grommet design featuring a sleeve body with a propeller-shaped opening, allowing for increased clearance without material stretching, and a tapered sleeve body with a propeller shape along a substantial part of its length to facilitate easy assembly and reduce the risk of material damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a standard circular opening is used in the grommet, then the mounting opening size can be kept small, but the clearance for receiving large diameter cables is insufficient and material stretching is required
Solution Approach 1:
The grommet opening transitions from a static circular shape to a dynamic propeller shape that can unfold during cable insertion. The propeller blades are designed to flex outward when force is applied, dynamically increasing the opening area from a compact folded state to an expanded reception state, allowing large diameter cables to pass through without requiring a permanently large mounting opening
Solution Approach 2:
The opening geometry transitions from a two-dimensional circular cross-section to a three-dimensional propeller configuration with radial blades extending outward. This dimensional change allows the opening to achieve a larger effective area by utilizing radial space rather than just increasing the circular diameter, enabling the grommet to accommodate large cables while maintaining a compact mounting footprint
2Area of moving object
If the grommet opening is stretched to accommodate large diameter cables, then the clearance is increased, but the material is at risk of damage and the production process becomes more complex
Solution Approach 1:
The propeller-shaped opening provides a controlled dynamic expansion mechanism where the blades flex outward in a predetermined manner during cable insertion. This dynamic behavior allows the opening to temporarily increase its area to accommodate large diameter cables while returning to its original compact shape afterward, preventing permanent material deformation or damage that would occur with continuous stretching
Solution Approach 2:
The opening is segmented into multiple propeller blades rather than being a continuous circular rim. This segmentation allows each blade to independently flex and move outward during cable insertion, distributing the mechanical stress across multiple discrete elements rather than concentrating it in a single stretched material structure, thereby reducing the risk of material failure
3Area of moving object
If a larger mounting opening is used to accommodate large diameter cables, then the clearance is sufficient, but the mounting opening size increases beyond current standards
Solution Approach 1:
The grommet utilizes a propeller geometry that extends the opening area radially outward from the central mounting hole rather than increasing the mounting hole diameter itself. The propeller blades create additional reception area in the radial dimension while the central mounting opening remains compact, allowing large diameter cables to be received without enlarging the stationary mounting opening in the vehicle bulkhead
4Productivity
If traditional grommet assembly processes are used, then the production process is well-established, but the process is time-consuming and requires significant operator effort
Solution Approach 1:
The propeller-shaped grommet is designed to be self-installing through a simple insertion motion. When the grommet is pushed into the mounting opening, the propeller blades automatically flex outward and then spring back to secure the cable harness in place, eliminating the need for operators to perform complex manipulation steps or apply sustained forcing actions that characterize traditional grommet installation processes
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 propeller-shaped grommet design allows for easier and more flexible insertion of cables and harnesses, reduces the need for large forces during assembly, and enables the use of larger diameter cables while maintaining the current mounting opening size or smaller, thus improving production efficiency and automatability.
Implementation Method 1
The standard grommet material currently employed e.g., in the automotive industry can be stretched up to 400%. The inventive design of a propeller shaped opening allows a significant increase in the clearance of the grommet without the need to stretch the material, as the propeller shaped opening can be unfolded
Data Source
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AI summary
The present invention relates to a grommet for receiving cables, such as a harness for a vehicle. The grommet comprises a sleeve body of a flexible material having two opposed openings, where at least one of the openings in unloaded condition has a cross sectional shape, as seen in axial insertion direction, of a propeller.