Disposable Ratchet Driver Torque Limiting Mechanism
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Solution Overview
Problem
Current disposable torque-limiting drivers in the medical industry face challenges in imparting higher torques required for larger applications, as traditional disposable drivers are limited to lower torque values, and reusable drivers require frequent recalibration and sterilization, making them cumbersome.
Innovation Solution
A disposable torque-limiting ratchet driver with a plastic gear drive mechanism that includes a cylindrical body, upper and lower shanks with gear teeth, a coil spring, and ratchet teeth, which disengages at a predetermined torque limit, allowing for higher torque transmission without the need for recalibration or sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional disposable drivers are used, then the device is simple and disposable, but the torque capability is limited to low values (4-20 inch-ounces)
Solution Approach 1:
The drivetrain is divided into multiple gear stages (first gear stage with first and second gears, second gear stage with third and fourth gears) that work together in series. Each gear stage provides torque multiplication, allowing the disposable driver to achieve high torque output (up to 120 inch-pounds) from a low-torque motor, resolving the contradiction between disposable simplicity and high torque capability
Solution Approach 2:
Gear mechanisms serve as intermediaries between the motor and the drive output. The multiple gear stages act as mechanical mediators that transform low-torque motor input into high-torque output, enabling disposable drivers to overcome their inherent torque limitations without requiring complex electronic control or calibration systems
2Measurement precision
If reusable drivers are used, then torque precision can be maintained, but frequent recalibration and sterilization are required
Solution Approach 1:
The drivetrain components (gears, shafts, bearings) are pre-assembled and pre-calibrated as a complete integrated unit during manufacturing. This preliminary assembly ensures precise torque transmission ratios are established before use, eliminating the need for field recalibration and allowing the entire driver to be disposed of after use without requiring sterilization or maintenance
Solution Approach 2:
The driver is designed as a disposable tool with a planned service life of a single use or limited uses. By accepting the device as short-lived, the design eliminates complex sterilization systems and recalibration mechanisms, focusing instead on ensuring precise torque delivery during the brief operational period through pre-calibrated mechanical gear trains
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 solution enables the disposable driver to impart torques up to 120 inch-pounds, reducing the number of part-to-part torque transitions and providing a reliable, precise, and efficient solution for medical applications, eliminating the need for frequent recalibration and sterilization.
Implementation Method 1
a coil spring between the upper cylindrical shank and the ribbed nut, wherein the spring is configured to apply a force across the upper clutch shank and the lower shank
Implementation Method 2
a plurality of ratchet teeth formed or molded on the inner annular wall; one or more of movable drive bodies mounted to the upper clutch shank with a toe that protrudes through a passageway beyond the annular wall to engage a ratchet tooth when rotated in the positive lock direction
Data Source
AI summary
A disposable ratcheting device and method is disclosed, which may include a shaft extending axially through at least a shank. The shank also provides a cup or chamber wherein a series of drive bodies reside in a movable fashion. The shank is placed in a body having an inner wall with teeth formed radially, The drive bodies have toes protruding beyond the shank and which, in a locked direction, engage the teeth inside the body.