Torque Retaining Device Segmentation for Anti-Rotation
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Solution Overview
Problem
Existing torque retaining devices, such as flag bolts and flag nuts, face issues like material inefficiency, increased tooling costs, weight concerns, corrosion, and difficulty in removal, which hinder efficient assembly and maintenance, especially in confined spaces and large assemblies where simultaneous access to both the nut and fastener is not feasible.
Innovation Solution
A torque retaining device with an engagement portion and an elongated portion that includes a flexible member to prevent unitary rotation of a nut and fastener, featuring a cavity for the fastener head or nut and radially extending sidewalls for rotational engagement, allowing for secure tightening without the need for simultaneous access, and an optional over-molded design for enhanced functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flag bolts and flag nuts are used to prevent rotation, then the fastener can be tightened without unitary rotation, but the device uses more material and increases weight
Solution Approach 1:
The torque retaining device is divided into separate components: a torque retaining member with an elongated portion and engagement portion, and a fastener. The elongated portion engages the workpiece to prevent rotation, while the engagement portion receives the fastener head or nut. This segmentation allows each component to be optimized independently, reducing overall weight while maintaining the anti-rotation function.
Solution Approach 2:
The torque retaining device is designed as a disposable component that remains attached to the workpiece after fastening. By using a simple, inexpensive structure with minimal material, the device achieves its single-use purpose of preventing unitary rotation during assembly, then is discarded, avoiding the need for expensive, heavy, reusable alternatives.
2Reliability
If flag bolts and flag nuts are used to prevent rotation, then the fastener can be tightened without unitary rotation, but the device requires increased tooling costs
Solution Approach 1:
The device is segmented into simple geometric components (elongated portion with sidewalls and an engagement portion) that can be manufactured using basic molding or machining processes. This segmentation avoids complex integral structures, reducing tooling costs while maintaining the anti-rotation function.
Solution Approach 2:
The design allows for parameter variations in the elongated portion (such as sidewall height, thickness, and engagement geometry) to be optimized for different applications without changing the fundamental structure. This flexibility enables standardization and simplifies manufacturing tooling requirements.
3Reliability
If integral flags are used, then rotation is prevented, but the device can only be used once and utilizes more material
Solution Approach 1:
The torque retaining device separates the anti-rotation function (elongated portion) from the fastening function (engagement portion). This segmentation allows the elongated portion to be made from minimal material just sufficient for engagement, eliminating excess material used in traditional integral flag designs.
Solution Approach 2:
The engagement portion is extracted as a separate functional element that receives the fastener head or nut, while the elongated portion remains attached to the workpiece. This extraction allows each component to be optimized for its specific function with minimal material usage.
4Reliability
If thin, highly corrosive metal flags are used, then rotation is prevented, but the flag corrodes and spreads to more expensive parts via metallic contact
Solution Approach 1:
The material properties of the torque retaining device are changed from thin, highly corrosive metal to materials with appropriate corrosion resistance. The device can be manufactured from plastics, coated metals, or other materials that provide the necessary mechanical strength for anti-rotation while resisting corrosion and preventing harmful metallic contact with other parts.
Solution Approach 2:
The torque retaining device can be constructed from composite materials or multi-layer structures that combine mechanical strength with corrosion resistance. For example, a plastic substrate with a metal reinforcement layer or a metal base with a protective coating prevents both unitary rotation and corrosion-related harm to other parts.
5Reliability
If the flag has corroded, then rotation is prevented, but removal of the fastener becomes difficult requiring extra time and tools
Solution Approach 1:
The engagement portion is extracted as a separate component that can be easily removed from the fastener head or nut after fastening. This extraction allows the fastener to be independently removed for maintenance or replacement without being constrained by a corroded integral flag structure.
Solution Approach 2:
The material properties and design of the engagement portion are optimized to prevent corrosion that would bind it to the fastener. By using corrosion-resistant materials and designing the engagement geometry to allow for easy release, the fastener can be quickly removed using standard tools without the complications of corroded flags.
Data Source
AI summary
A torque retaining device for preventing unitary rotation of a nut and a fastener extending through two parts to be connected is provided. The torque retaining device includes an engagement portion for connection to one of the nut and a fastener head and an elongated portion for rotationally catching on one of the parts that the fastener is to be extended through. The engagement portion includes a wall having an inner side that defines a cavity for placement of the fastener head or nut and is shaped rotate with the fastener head or nut. At least one flexible member extends radially inwardly from the inner side of the wall for holding the fastener head or nut in the engagement portion.