Cross-strap tensioning for osteoarthritis braces
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Solution Overview
Problem
Existing knee braces struggle to maintain a load directly across the knee joint during movement while allowing independent movement of the cross-straps, leading to potential counteracting forces and strap misalignment.
Innovation Solution
A cross-strap tensioning apparatus with first and second cross-straps that intersect at the joint, featuring a tensioning mechanism to urge strap portions closer together, and tethers to maintain alignment, allowing independent movement while maintaining load distribution across the joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the force straps are tightened to increase unloading force on the knee, then the knee is drawn towards the hinge and might strike the hinge, resulting in counteracting forces that negate the unloading effect
Solution Approach 1:
A pad is introduced as an intermediary element positioned between the hinge and the knee. This pad prevents direct contact and counteracting forces when the knee approaches the hinge during movement, allowing the force straps to maintain their unloading function without being negated by hinge interference.
Solution Approach 2:
The system allows dynamic adjustment of strap tension and accommodates dynamic movement of the knee joint. The force straps can be tightened to provide necessary unloading force while the system adapts to the changing position of the knee during gait, preventing the knee from striking the hinge through controlled movement ranges.
2Adaptability or versatility
If the force straps are allowed to move to accommodate joint movement, then movement freedom is improved, but the straps tend to slip above, below or to the side of the knee, losing proper positioning
Solution Approach 1:
The system incorporates feedback mechanisms through the interaction between the force straps, cross-straps, and hinge structure. The cross-straps act as guides that provide positional feedback to the force straps, ensuring they remain correctly positioned on the knee while accommodating the range of motion required during gait.
Solution Approach 2:
The cross-straps are positioned at an angle relative to the force straps, creating a multi-dimensional constraint system. This angular arrangement provides stability in multiple directions simultaneously, preventing the force straps from slipping in any direction while allowing necessary joint movement.
3Force
If the cross-straps are positioned to maintain load across the joint center, then unloading effectiveness is improved, but the straps cannot move independently during joint movement, causing misalignment
Solution Approach 1:
The strap system is divided into separate functional components: force straps that apply unloading force and cross-straps that provide positional guidance. This segmentation allows each component to perform its specific function independently - the force straps maintain load distribution while the cross-straps enable independent movement without causing misalignment.
Solution Approach 2:
The cross-straps are positioned asymmetrically at angles relative to the force straps, creating a non-uniform geometric arrangement. This asymmetric configuration allows the force straps to maintain their positioning for optimal load distribution across the joint center while the cross-straps provide the necessary geometric constraints for independent movement during gait.
Data Source
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AI summary
A cross-strap tensioning apparatus is disclosed for use with a brace having a proximal portion engageable above a joint of a user and an opposing distal portion engageable below the joint. In at least one embodiment, the apparatus provides first and second cross-straps each extending between and interconnecting the proximal and distal portions of the brace. A terminal end of each of a first anterior strap portion and a spaced apart first posterior strap portion of the first cross-strap, along with a second anterior strap portion and a spaced apart second posterior strap portion of the second cross-strap, provides a cord channel configured for allowing a cord from a tensioning mechanism to extend therethrough in series. During use, as the tensioning mechanism is selectively tightened, the cord urges each of the first anterior strap portion, first posterior strap portion, second anterior strap portion and second posterior strap portion closer together.