Bone Plate Bending Cage Prevents Rotational Play
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Solution Overview
Problem
Existing bone fixation plate bending instruments fail to efficiently apply bending forces in the horizontal plane due to rotational play and slippage, making it difficult to achieve desired bends without misdirection of force or plate slippage.
Innovation Solution
A system comprising elongate bending bars and a bending cage that restricts rotational movement while allowing lateral motion, ensuring that bending forces are applied parallel to the primary axes of the openings, thereby maintaining the applied load along the desired axis and preventing plate slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a bending iron with an oversized opening is used to allow easy insertion of the plate, then ease of operation is improved, but rotational play and misdirection of bending force occur
Solution Approach 1:
The patent introduces a bending cage as an intermediary device between the bending iron and the plate. The cage has openings that are precisely sized to fit the plate dimensions, eliminating rotational play. The bending iron passes through the cage, allowing the cage to act as a mediator that constrains the plate's rotational movement while still permitting the bending iron to apply force effectively.
Solution Approach 2:
The patent divides the bending system into two separate components: a bending iron for applying force and a bending cage for constraining movement. This segmentation allows each component to perform its specific function optimally - the iron provides leverage while the cage provides precise positioning and rotational constraint.
2Adaptability or versatility
If a bending iron is used to create horizontal bends, then the ability to bend the plate is improved, but the plate rotates to find maximal stability causing force misdirection
Solution Approach 1:
The bending cage serves as an intermediary constraint system that prevents the plate from rotating during horizontal bending. By providing fixed geometric boundaries through its openings, the cage ensures that the plate maintains its orientation while being bent, thereby ensuring accurate force transfer from the bending iron to the plate.
Solution Approach 2:
The plate is first inserted into the bending cage, which pre-establishes the correct orientation and positioning before the bending force is applied. This preliminary action of constraining the plate within the cage ensures that when the bending iron applies force, the plate is already in the correct stable position and cannot rotate during the bending process.
3Ease of operation
If the opening in the bending iron is larger than the plate dimensions, then ease of insertion is improved, but torsional play reduces bending effectiveness
Solution Approach 1:
The system is segmented into a bending iron with a larger opening for easy insertion and a bending cage with precisely fitted openings for efficient force transfer. This segmentation allows the insertion function and the bending efficiency function to be separated and optimized independently.
Solution Approach 2:
The bending cage acts as an intermediary that receives the plate after insertion and provides the precise geometric constraints needed for efficient bending. The cage's openings are sized to match the plate dimensions, eliminating torsional play while the bending iron's larger opening maintains ease of insertion.
Data Source
AI summary
A system and method for bending a bone fixation plate in the horizontal plane of the plate. The apparatus and method provide for optimization of applied bending moments by controlling the orientation of a bending tool to prevent deviation from an axis of bending. The system includes a bending bar or bars with an aperture or slot for engaging a plate or rod and a bending cage that can be in the shape of a rectangular box having a front surface separated from a rear surface by a distance. The front surface has a front elongate opening and the rear surface has a rear elongate opening. The front and rear openings are each formed by two parallel edges separated by a vertical distance and having a horizontal length. The relative dimensions of the respective bending bars and openings are such that the bending cage can be used to permit free movement of the bending bars in a direction parallel to the primary axis of the elongate openings but to prevent rotational movement of the bending bars about an axis substantially parallel to the length of the bending bars.