Torque-Limiting Fastener Shear Plane for Precise Break Torque
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Solution Overview
Problem
Existing torque limiting fasteners face challenges in accurately setting the torque at which they break, manipulating the fastener after breaking, and achieving precise breakage formations.
Innovation Solution
A torque limiting fastener design featuring a body with a controlled break region, including an outer and inner surface break point defining a shear plane, allowing for controlled breakage and tool access, with options for torque rating display, material selection, and geometric variations to achieve desired torque characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fastener is designed to break at a predetermined torque, then the torque limiting function is achieved, but the accuracy of setting the break torque is difficult
Solution Approach 1:
The patent applies preliminary action by pre-forming controlled break regions with specific geometries (such as notches, grooves, or reduced cross-section areas) at predetermined locations on the fastener body before the fastening operation. These pre-formed features ensure that the fastener will break at a specific, predetermined torque value, eliminating the difficulty of setting the break torque during operation. The controlled break regions are designed with precise dimensions and locations that correspond to the desired torque threshold.
Solution Approach 2:
The patent utilizes parameter changes by varying the geometric parameters of the controlled break regions (such as depth, width, shape, and location of notches or grooves) to achieve different torque thresholds. By changing these physical parameters of the break regions, the fastener can be designed to break at specific torque values without requiring additional adjustment mechanisms, thereby improving both the accuracy and predictability of the break torque.
2Reliability
If the fastener breaks controllably, then the torque limit is enforced, but the manipulation of the fastener after breaking becomes difficult
Solution Approach 1:
The patent applies segmentation by designing the controlled break regions to fracture in a way that creates separable segments or pieces. The fastener is engineered to break into distinct sections (such as the fastener body separating from the threaded portion, or breaking into manageable fragments) that can be easily removed or manipulated independently. This segmentation ensures that after the torque limit is enforced through breaking, the remaining portions can be easily handled, removed, or replaced without difficulty.
Solution Approach 2:
The patent utilizes taking out by designing the controlled break regions to allow a specific portion of the fastener to be extracted or removed after breaking. The break regions are positioned and configured so that when the fastener breaks, a problematic or unnecessary portion (such as the broken-off head or threaded section) can be easily extracted from the assembly, facilitating easy manipulation and removal of the failed fastener component.
3Ease of operation
If the fastener is designed with a threadform, then the fastening function is provided, but the breakage formation accuracy is difficult to achieve
Solution Approach 1:
The patent applies preliminary action by pre-forming controlled break regions with precise geometries (such as notches, grooves, or reduced cross-section areas) at predetermined locations on the fastener body before the fastening operation. These pre-formed features ensure that the fastener will break at a specific, predetermined torque value, eliminating the difficulty of setting the break torque during operation. The controlled break regions are designed with precise dimensions and locations that correspond to the desired torque threshold.
Solution Approach 2:
The patent utilizes parameter changes by varying the geometric parameters of the controlled break regions (such as depth, width, shape, and location of notches or grooves) to achieve different torque thresholds. By changing these physical parameters of the break regions, the fastener can be designed to break at specific torque values without requiring additional adjustment mechanisms, thereby improving both the accuracy and predictability of the break torque.
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
Enables accurate and predictable breakage with easy tool access and manipulation, ensuring precise breakage formations and compatibility with various tools and materials.
Implementation Method 1
The controlled break region includes an outer surface break point formed into the outer surface and an inner surface break point formed into the inner surface. The outer surface break point and the inner surface break point define a shear plane therebetween.
Data Source
AI summary
A torque limiting fastener comprises a body. The body defines a first body portion and a second body portion that extend from a first end of the body to a second end of the body. The body comprises an inner surface extending from the first end of the body to the second end of the body. The body further comprises an outer surface extending from the first end of the body to the second end of the body. The body yet further comprises an inner threadform extending substantially along a length of the inner surface of the second body portion and a controlled break region. The controlled break region is disposed at an intersection of the first body portion and the second body portion. The controlled break region includes an outer surface break point formed into the outer surface and an inner surface break point formed into the inner surface.