Spherical Locking Element for Bone Plate Tilting
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Solution Overview
Problem
Existing bone plate and screw connections in medical engineering lack flexibility in locking direction and angle, making it difficult to reposition bone segments without damaging the screw or plate, especially in complex fractures where precise positioning is required.
Innovation Solution
A housing with a spherical, parabolic, elliptical, or hyperbolic inner wall and a locking element with corresponding spherical, parabolic, elliptical, or hyperbolic outer surface, allowing tilting and reliable locking at various angles, which can be released without damage, using a 'tripod' principle and specific contour functions like root functions or logarithmic spirals, and incorporating groove-like depressions to prevent unwanted clamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bone screw is locked in a plate aperture with a conventional engagement contour, then reliable locking is achieved, but the locking can only be released by deforming the locking thread and engagement contour, which damages the screw and plate
Solution Approach 1:
The locking mechanism transitions from a static deformed state to a dynamic reversible state. The ball-shaped head with spherical clamping surface and the corresponding spherical recess allow the locking element to be tilted and repositioned, enabling release without permanent deformation. The system moves between locked and unlocked states through controlled tilting motion rather than irreversible deformation.
Solution Approach 2:
The patent introduces spherical geometry to both the locking element (ball-shaped head with spherical clamping surface) and the housing (spherical recess). This curvature allows multi-directional tilting and rotation, enabling the locking mechanism to be engaged and disengaged without damage. The spherical interfaces permit controlled movement and repositioning that was impossible with conventional planar or helical locking surfaces.
2Reliability
If the engagement contour is designed to lock the screw firmly, then automatic loosening is prevented, but the locking direction is restricted to a small angle range along the longer axis of the oblong plate aperture
Solution Approach 1:
The spherical clamping surface on the ball-shaped head and the matching spherical recess enable the locking element to tilt and lock in multiple directions, not just along a single axis. The spherical geometry provides rotational freedom while maintaining secure engagement, allowing adaptation to various screw orientations and fracture configurations.
Solution Approach 2:
The locking mechanism serves multiple functions: it prevents automatic loosening through spherical engagement, allows controlled tilting in multiple directions, enables easy release by tilting back, and permits repositioning of bone segments. This multi-functional design replaces the single-axis, single-purpose conventional locking mechanism.
3Stability of the object's composition
If the bone plate is positioned close to the bone for stable fixation, then mechanical stability is improved, but the periosteum is compromised, reducing blood circulation and nutrition to the bone
Solution Approach 1:
The reversible locking mechanism acts as an intermediary that enables stable fixation without requiring the plate to be in direct contact with the bone. The improved locking reliability allows the plate to be positioned at a distance from the bone surface, maintaining mechanical stability through the locking mechanism rather than through friction or contact pressure, thereby preserving the periosteum.
4Reliability
If a locking mechanism with deformation is used to ensure secure connection, then automatic loosening is avoided, but subsequent repositioning of bone segments becomes more difficult
Solution Approach 1:
The locking mechanism enables dynamic adjustment between locked and unlocked states. The spherical interfaces allow controlled tilting motion that can easily transition the system between these states, facilitating repositioning operations without requiring forceful deformation or damage to the components.
Solution Approach 2:
The spherical clamping surface and spherical recess provide smooth, continuous contact surfaces that facilitate easy tilting and repositioning. Unlike conventional sharp-edged or helical locking surfaces that require significant force to deform, the spherical geometry allows gentle tilting motion for release and repositioning while maintaining secure locked engagement when positioned correctly.
Data Source
AI summary
A locking element and a corresponding housing are disclosed, for the locking of the locking element in housing. The locking element includes a locking piece, for example a head, with a peripheral outer surface, running essentially in the direction of a longitudinal axis with at least one clamping surface extending outwards from the longitudinal axis in the form of a wedge, in order to lock the locking piece on the locking element with a corresponding inner contour of the housing. The peripheral outer surface is at least approximately spherical, parabolic, elliptical or hyperbolic in embodiment, viewed in the direction of the longitudinal axis in the region of the clamping surface, which is also true for the inner contour of the housing in the region of the recess, whereby the recess cooperating with the clamping surface can also be cylindrical.