Sequential Torque Screw Drive to Prevent Cam-Out Misalignment

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Solution Overview

Problem

Conventional fasteners that require high torque often fail when the torqueing tool is not aligned with the central axis, as all torque is applied via a single drive feature, leading to cam out of alignment issues.

Innovation Solution

A sequential torque application retention system that includes a driver mechanism with a center drive and an outboard drive, where the center drive is engaged first to apply an initial torque, and the outboard drive is engaged subsequently to apply a subsequent torque, distributing the torque across multiple drive features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all torque is applied via a single drive feature, then the fastener can be driven, but the fastener fails when the torqueing tool is not aligned with the central axis

Engineering Contradiction:

Improvefastener reliabilityVSAvoiddrive feature complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The single drive feature is segmented into multiple drive features: a central drive feature and at least one outboard drive feature. This segmentation allows the torque to be distributed across multiple engagement points, preventing cam-out when misalignment occurs and improving overall fastener reliability.

Inventive Principle:

Principle #1Segmentation

2Strength

If a single drive feature is used, then the structure is simple, but the screw head requires greater thickness to handle high torque

Engineering Contradiction:

Improvescrew head strengthVSAvoidscrew head thickness

Core Design Contradiction:

StrengthVSLength of stationary object

Solution Approach 1:

The drive feature is divided into central and outboard components, allowing the torque load to be distributed across multiple engagement points. This reduces the stress concentration in the screw head, enabling thinner screw head designs while maintaining the required strength for high torque applications.

Inventive Principle:

Principle #1Segmentation

3Reliability

If the outboard receivers are positioned to engage with the outboard drive, then torque distribution is improved, but the outboard drive may engage prematurely during initial torque application

Engineering Contradiction:

Improvetorque application reliabilityVSAvoidtorque application control

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The outboard receivers are positioned at specific locations and oriented at specific angles relative to the central receiver. This local differentiation ensures that the outboard drive features only engage when properly aligned and subjected to sufficient torque, preventing premature engagement while maintaining reliable torque distribution.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12305684B2Sequential torque application retention system

Publication Date: 2025.05.20 RAYTHEON CO

AI summary

A sequential torque application retention system includes a driver mechanism having a shaft; a center drive coupled to a tip end; an outboard drive coupled to the tip end; a screw including a screw head with a central receiver, the central receiver corresponding to the center drive, the central receiver configured to receive the center drive; a pair of outboard receivers formed in the screw head corresponding to the outboard drive, the pair of outboard receivers configured to receive the outboard drive; wherein the center drive is engaged with the screw head at the central receiver responsive to an initial torque and the outboard drive is engaged with the screw head at the pair of outboard receivers responsive to a subsequent torque; and wherein the outboard receivers are positioned so that they do not engage with the outboard drive responsive to the initial torque.