Torque-Limiting Screwdriver With Feedback to Prevent Screw Stripping

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Solution Overview

Problem

Conventional screwdrivers used in orthopedic surgeries often apply excessive torque, leading to screw stripping in bones, which can compromise the securement of screws and plates, and lack user comfort and precision, resulting in high misplacement rates and risks to adjacent tissues.

Innovation Solution

A torque-limiting screwdriver with a motor and torque-sensing mechanism that monitors and controls torque application, switches between manual and powered modes, and provides feedback to users, reducing rotational speed and preventing unintentional rotation to enhance precision and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional power-operated screwdrivers are used to provide sufficient torque for screw insertion, then the torque requirement is met, but the device becomes heavy and lacks user comfort

Engineering Contradiction:

ImprovetorqueVSAvoiduser comfort

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The screwdriver dynamically adjusts its operating mode between manual and powered based on real-time torque sensing. The system transitions from manual mode during initial screw engagement to powered mode when torque threshold is exceeded, providing adaptive torque assistance only when needed. This dynamic switching resolves the contradiction by delivering high torque on demand while maintaining light weight and user comfort during non-powered phases.

Inventive Principle:

Principle #15Dynamics

2Productivity

If high rotational speed is used for efficient screw insertion, then productivity is improved, but the likelihood of unintentional rotation and screw stripping increases

Engineering Contradiction:

Improveinsertion efficiencyVSAvoidscrew securement

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The screwdriver incorporates real-time torque sensing that continuously monitors torque during screw insertion. When the sensed torque approaches a predetermined threshold indicating potential stripping, the system provides feedback by reducing rotational speed or stopping rotation. This feedback mechanism resolves the contradiction by maintaining high speed for efficiency while automatically preventing unintentional rotation that would compromise screw securement.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If manual screw driving is used to maintain precision and control, then misplacement rate is reduced, but surgical time increases

Engineering Contradiction:

Improvescrew placement precisionVSAvoidsurgical time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The screwdriver system performs self-monitoring of torque conditions and automatically transitions between manual and powered modes without requiring constant user intervention. The torque sensor detects when assistance is needed and the powered motor engages autonomously to complete screw insertion. This self-service capability maintains precision through user control during critical phases while reducing surgical time through automated torque assistance during insertion.

Inventive Principle:

Principle #25Self-service

4Reliability

If torque monitoring and speed reduction features are added to prevent screw stripping, then screw securement is improved, but device complexity increases

Engineering Contradiction:

Improvescrew securementVSAvoiddevice structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The screwdriver replaces complex mechanical torque-limiting mechanisms with an electronic torque sensing system. A torque sensor electronically monitors applied torque and triggers motor control to reduce speed or stop rotation when thresholds are approached. This electronic substitution resolves the contradiction by providing reliable screw securement through intelligent control while avoiding the mechanical complexity of traditional torque-limiting devices.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 screwdriver reduces screw stripping, improves user comfort, minimizes misplacement, and enhances surgical precision by limiting torque and providing real-time feedback, thereby reducing surgical time and risks to surrounding tissues.

Implementation Method 1

The screwdriver can include a body and a motor. The motor can be operably connected to a drive head at a distal end of the screwdriver such that the motor can turn the drive head.

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

A torque-limiting screwdriver with a motor and torque-sensing mechanism that monitors and controls torque application

Methodology Applied

Scientific EffectTorque sensing: Torque

Data Source

PatentUS12376936B2Torque-limiting screwdriver devices, systems, and methods

Publication Date: 2025.08.05 PRO DEX INC

AI summary

Various torque-limiting screwdriver devices, systems, and methods are disclosed. The screwdriver can include a body, a motor that is configured to rotate a screw engaged with the screwdriver, and a processor configured to control operation of the screwdriver. The screwdriver can have torque-limiting functionality, such as by monitoring the amount of torque applied to the screw and reducing or stopping rotation of the screw when certain torque-limiting criteria are met. In some embodiments, the screwdriver can be switched between manual operation by a user, and automated operation by a motor within the screwdriver. In some embodiments, the screwdriver can be attached to a robotic arm.