Orthopedic Screw Extractor Tip for Stripped Screw Grip
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Solution Overview
Problem
Conventional orthopedic screw extractors fail to provide sufficient grip to remove stripped or damaged screws, leading to difficult extraction procedures and excessive bone loss.
Innovation Solution
An orthopedic screw extractor with a frustoconical screw extracting tip featuring multiple threads and flutes, designed to securely engage and remove damaged screws using a narrow taper angle, buttress thread configuration, and a titanium nitride coating for enhanced torque application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional orthopedic screw extractors are used, then the device structure is simple, but the extractor cannot provide sufficient grip to remove stripped or damaged screws
Solution Approach 1:
The extractor tip is segmented into multiple functional zones: a frustoconical engagement surface with multiple flutes for initial biting and locking, followed by screw threads for secure attachment. This segmentation allows each zone to perform its specific function optimally, providing reliable grip on damaged screws.
Solution Approach 2:
The extractor incorporates a titanium nitride coating on its surface, creating a composite structure that combines the mechanical strength of the base material with the enhanced friction and grip properties of the coating layer, thereby improving reliability without significantly increasing complexity.
2Loss of substance
If conventional screw extractors are used, then the device is easy to manufacture, but excessive bone loss occurs during extraction
Solution Approach 1:
The frustoconical tip with flutes performs preliminary action by biting into and locking onto the damaged screw before the main extraction force is applied. This preliminary engagement secures the extractor to the screw, enabling controlled removal that minimizes bone loss while maintaining manufacturing feasibility.
3Productivity
If conventional screw extractors are used, then the device structure is simple, but the extraction procedure becomes difficult and time-consuming
Solution Approach 1:
The extractor design incorporates dynamic elements including the frustoconical shape that facilitates progressive engagement, multiple flutes that provide progressive biting action, and screw threads that enable secure attachment. These dynamic features work together to streamline the extraction process, improving productivity while maintaining reasonable design complexity.
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 screw extractor effectively locks onto and removes damaged screws with minimal bone loss, facilitating efficient extraction and reducing the risk of device spin-off during operation.
Implementation Method 1
The screw extracting tip further includes first, second and third screw threads, wherein each screw thread has a lead of about 0.07 to 0.12 inches, a pitch of about 0.02 to 0.04 inches, a thread angle of about 40 to 50 degrees, and a depth of about 0.01 to 0.02 inches
Implementation Method 2
The screw extracting tip further includes first, second and third flutes circumferentially spaced about the screw extracting tip and extending across an entire length of the screw extracting tip
Data Source
AI summary
An orthopedic screw extractor device including a shaft, an end portion about a first end of the shaft for securing to a handle, and a screw extracting tip about a second end of the shaft opposite the first end. The screw extracting tip further includes a generally frustoconical shape having a side at an angle of about 5 to 15 degrees relative to a longitudinal axis of the screw extracting tip. The screw extracting tip further includes first, second and third screw threads and first, second and third flutes circumferentially spaced about the screw extracting tip and extending across an entire length of the screw extracting tip. Each of the screw threads has a lead of about 0.07 to 0.12 inches, a pitch of about 0.02 to 0.04 inches, a thread angle of about 40 to 50 degrees, and a depth of about 0.01 to 0.02 inches.