Bone Screw Tool Attachment With Asymmetric Alignment Aid
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Solution Overview
Problem
Existing screw driver attachment to screws in surgical procedures is time-consuming and error-prone due to the need for precise rotational alignment, especially under difficult visual conditions, and existing alignment aids reduce torque transmission.
Innovation Solution
A screw element with an asymmetrically designed tool attachment point featuring larger contact surfaces in the insertion direction and smaller surfaces in the removal direction, combined with a guiding alignment aid, allowing for efficient alignment and high torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If symmetrically arranged tapered guide grooves are provided on each tooth profile to enable assembly in any rotational position, then ease of operation is improved, but torque transmission capability deteriorates due to reduced contact surfaces
Solution Approach 1:
The patent applies asymmetry by providing the alignment aid (tapered guide groove) only in one specific tooth profile rather than symmetrically in all tooth profiles. This asymmetric placement allows the alignment groove to be positioned where it does not interfere with the contact surfaces of other tooth profiles, thereby maintaining torque transmission capability while still enabling easy assembly through rotational alignment.
2Ease of operation
If contact surfaces in the removal direction are made smaller to allow space for alignment aid, then ease of operation is improved, but torque transmission in removal direction deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the contact surface areas in different directions. The insertion direction maintains large contact surfaces for high torque transmission during screwing in, while the removal direction has smaller contact surfaces that accommodate the alignment aid. This localized differentiation optimizes both alignment ease and torque transmission for each operational direction.
3Strength
If precise rotational alignment is required for screw driver attachment, then torque transmission is improved, but productivity deteriorates due to time-consuming alignment process
Solution Approach 1:
The patent applies preliminary action by incorporating the alignment aid (tapered guide groove) into the tool attachment point design before assembly occurs. This pre-configured alignment feature guides the screw driver into the correct rotational position automatically during insertion, eliminating the need for manual trial-and-error alignment and significantly speeding up the assembly process while ensuring proper alignment for torque transmission.
Data Source
AI summary
A screw element for the fixation of bone components and bone fragments is disclosed having a shaft with an outside screw thread and a longitudinal axis extending along the shaft and defining a distal direction and a proximal direction, and an insertion direction and an opposite removal direction, and has a tool attachment point starting radially inwards and the tool attachment point has a central opening and in the wall of this opening at least five tooth profiles directed radially outwards and mainly parallel to the screw axis directed radially outwards and mainly parallel to the screw axis are formed in the wall of this opening, and for each tooth profile an insertion wall in insertion direction and a removal wall in removal direction can be separated, and that the surface of the insertion wall is greater than the surface of the removal wall.