Bone Fixation Screw with Identical Thread Pitch

Solution Overview

Problem

Existing bone fixation systems with screws experience compression effects due to differing thread pitches between the screw head and shaft, leading to potential displacement of bone segments.

Innovation Solution

A system featuring an implant plate with a bore and an implant screw where the thread pitch is identical along the screw shaft and head, preventing compression effects and ensuring a secure locking connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the screw head has a thread with a smaller metric pitch than the bone thread at the screw shaft, then the screw can be securely anchored in the bone, but compression effects occur during tightening that may displace bone segments

Engineering Contradiction:

Improvescrew anchoring strengthVSAvoidbone segment position stability

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by providing the screw with two distinct thread sections having different pitches: a first thread section at the screw shaft with a larger pitch for secure bone anchoring, and a second thread section at the screw head with a smaller pitch for plate engagement. This localized differentiation allows each region to perform its specific function optimally without causing compression effects on the bone segments.

Inventive Principle:

Principle #3Local quality

2Strength

If the screw head diameter is enlarged relative to the screw shaft diameter, then the screw can lock securely with the plate, but the screw cannot be screwed through the plate into the bone without connection to the plate first

Engineering Contradiction:

Improvescrew-plate locking strengthVSAvoidscrew insertion ease

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent segments the screw into two functional parts: a narrower screw shaft that can be inserted through the plate bore into the bone first, and an enlarged screw head that subsequently locks with the plate. This segmentation allows the insertion sequence to be reversed compared to conventional screws, enabling the screw to be screwed into the bone without preliminary connection to the plate.

Inventive Principle:

Principle #1Segmentation

3Strength

If a thread is provided in the head region with a smaller metric pitch than the bone thread, then the screw engages the plate securely, but compression effects occur that can displace the bone segment

Engineering Contradiction:

Improvescrew-plate engagement strengthVSAvoidcompression effects on bone

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by providing the screw with two distinct thread sections having different pitches: a first thread section at the screw shaft with a larger pitch for secure bone anchoring, and a second thread section at the screw head with a smaller pitch for plate engagement. This localized differentiation allows each region to perform its specific function optimally without causing compression effects on the bone segments.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9848926B2System for the fixation of bone segments or bone fragments

Publication Date: 2017.12.26 KARL LEIBINGER ASSET MANAGEMENT GMBH & CO KG

AI summary

The present disclosure relates to a system for the fixing of bone segments or bone fragments comprising an implant plate or an implant surface plate having a bore or a cut-out and comprising an implant screw which can be guided through the bore or cut-out of the plate, wherein the implant screw has a screw shaft and a screw head and wherein both the screw shaft and the screw head have a thread with identical pitches.