Adjustable Prosthetic Socket with Radial Tensioning
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Solution Overview
Problem
Conventional prosthetic sockets are rigid and fail to accommodate shape and volume fluctuations of residual limbs, leading to discomfort and potential injury due to labor-intensive and complex tightening systems that are difficult for patients with limited dexterity or cognition to use.
Innovation Solution
An adjustable socket system with a base, longitudinal supports, and shell components that can move radially to loosen or tighten the fit, featuring a tensioning unit with a handle and pulley assemblies to provide mechanical advantage, allowing easy donning and doffing, and secondary tensioners for fine-tuning the fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional rigid sockets are used, then manufacturing simplicity is maintained, but adaptability to residual limb volume and shape fluctuations is lost
Solution Approach 1:
The socket structure transitions from a static rigid form to a dynamic adjustable form through the integration of tensioning elements and movable connection points. The shell components can move radially inward or outward relative to the longitudinal axis, allowing the socket to adapt to volume and shape fluctuations of the residual limb while maintaining structural integrity.
Solution Approach 2:
The socket is divided into multiple adjustable components including shell components, longitudinal supports, and tensioning elements. This segmentation allows independent adjustment of different regions of the socket to accommodate varying limb dimensions while simplifying the adjustment mechanism for each individual component.
2Manufacturing precision
If labor-intensive tightening systems are used, then fit precision is improved, but ease of operation deteriorates
Solution Approach 1:
The complex mechanical tightening system is replaced with a simplified tensioning mechanism featuring a handle that defines a moment arm. Rotation of the handle about a rotation axis provides mechanical advantage, requiring less user strength to achieve proper fit precision. The tensioning element translates rotational motion into radial movement of the shell components.
Solution Approach 2:
The socket system incorporates self-adjusting features where the tensioning element automatically tensions the shell components to the appropriate fit level. The movable connection points and pulley assemblies work together to distribute tension evenly, reducing the need for manual adjustment and making the system easier for patients with limited dexterity to operate.
3Ease of operation
If movable connection points are exposed, then ease of adjustment is improved, but reliability and safety deteriorate
Solution Approach 1:
The movable connection points and pulley assemblies are nested within the structural framework of the longitudinal supports and shell components. This nesting protects the movable parts from accidental contact and damage while maintaining their functionality. The connection points remain accessible for intentional adjustment but are shielded from external objects that could cause unintended movement or damage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system improves ease of use, reduces the risk of injury, and ensures proper fitting by providing a simple and intuitive mechanism for users with limited dexterity, enhancing comfort and safety.
Implementation Method 1
the handle defines a moment arm rotatable about a rotation axis... Because the handle defines a moment, it provides a user a mechanical advantage, requiring less user strength to move the tensioning unit between the on position and the off position
Implementation Method 2
The at least one movable connection point comprises first and second pulley assemblies on a displacement wheel... rotation of the displacement wheel moves the first pulley assembly in an arcuate or circular path with the second pulley assembly moving in an arcuate or circular path above or below the first pulley assembly... helps reduce friction and the level of physical effort needed to move the handle
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An adjustable socket system (900) includes first and second longitudinal supports (904A, 904B) connected to a base (902), and first and second shell components (906A, 906B) connected to the supports (904A, 904B). A tightening system (914) includes a tensioning unit (918) having a handle (932) defining a moment arm rotatable about a rotation axis (934), and a tensioning element (920) operatively coupled to the handle (932) via a movable connection point (938) located and protected between the second shell component (906B) and the second support (904B), and to the shell components (904A, 904B) via a control point (924). Rotation of the handle (932) displaces the movable connection point (938) and the tensioning element (920) relative to the control point (924) to move the socket system (900) from an open configuration to a closed configuration to secure the fit of the socket system (900) on residual limb received therein.