Cable Tie Pawl Design for Low Insertion Force and High Holding Strength
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Solution Overview
Problem
Conventional cable ties experience excessive bending stress on the pawl, leading to disengagement due to high insertion forces when attempting to increase holding force, as they rely on bending loads rather than tensile loads.
Innovation Solution
A cable tie design featuring a pawl with a stem region of smaller cross-sectional area for low insertion forces and a securing region with multiple barbs and a stabilizing surface, shifting the load from bending to tension, and embedding the pawl in a two-piece construction with a band and pawl made of different materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pawl is designed to rely on bending loads to engage the tail section, then the holding force can be increased, but the insertion forces become excessively high
Solution Approach 1:
The patent inverts the conventional loading approach by designing the pawl to engage the tail section through tensile loads rather than bending loads. The pawl features a stabilizing surface that contacts the insertion channel wall to prevent bending, while barbs engage the tail to resist tensile forces, effectively reversing the traditional force application method to achieve both low insertion forces and high holding force
Solution Approach 2:
The patent changes the fundamental loading parameter from bending to tension. By redesigning the pawl geometry with a stabilizing surface and barb configuration, the engagement mechanism transitions from relying on bending deformation to relying on tensile resistance, fundamentally altering how forces are applied and resisted in the system
2Strength
If the pawl cross-sectional area is increased to prevent bending, then the bending resistance improves, but the insertion forces increase
Solution Approach 1:
The patent applies local quality by providing bending resistance only where needed through the stabilizing surface that contacts the insertion channel wall, rather than increasing the overall pawl cross-sectional area. This localized support prevents bending at the critical engagement point while maintaining a slender overall pawl structure that requires low insertion forces
Solution Approach 2:
The stabilizing surface acts as an intermediary element between the pawl and the insertion channel wall. This intermediate contact surface provides the necessary bending resistance by transferring loads to the channel wall, eliminating the need to increase the pawl's own cross-sectional area for bending strength
3Strength
If conventional pawl design is used with single-piece construction, then the device complexity is low, but the holding force is insufficient
Solution Approach 1:
The patent segments the cable tie system into two distinct components: a band and a separate pawl. This segmentation allows the pawl to be independently optimized with complex features like barbs and stabilizing surfaces for enhanced holding force, while the band remains simple. The two-piece construction enables functional optimization that would be difficult to achieve in a single-piece design
Data Source
AI summary
A cable tie includes a band of one material and a pawl of a different material. The pawl has a stem region and a securing region, wherein the securing region includes at least one barb and a stabilizing surface opposite the at least one barb. The band includes a head section and a tail section that may be inserted through the head section to secure a load. The head section includes a base section into which at least a portion of the stem region of the pawl is inserted, and an insertion channel to receive the tail section, wherein at least a portion of the pawl extends into the insertion channel. When a load is exerted to remove the tail section from the insertion channel, the barb engages the tail section and the stabilizing surface contacts a wall of the insertion channel to prevent bending of the pawl.