Prosthetic Socket Disc Adapter for Pistoning Reduction

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Solution Overview

Problem

Conventional lower limb prosthetic devices using long, narrow pins for suspension suffer from issues like wobbling, wear, and improper operation due to dirt infiltration, leading to undesirable pressure transfer and 'pistoning' of the residual limb, which can cause discomfort and instability during use.

Innovation Solution

A prosthetic device with an inner socket assembly and an outer socket assembly secured through a coupling mechanism featuring a disc-shaped adapter and receptacle, providing a stable, non-rotational interface and utilizing a vacuum system to maintain the residual limb securely in place, thereby reducing movement and pressure concentration on the pin.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If long, narrow pins are used for suspension, then the prosthetic device can be securely attached, but wobbling, wear, and dirt infiltration occur leading to improper operation

Engineering Contradiction:

Improvesuspension securityVSAvoidwobbling, wear, dirt infiltration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The suspension system is divided into multiple components: an inner socket assembly, an outer socket assembly, and a coupling mechanism with disc-shaped adapter and receptacle. This segmentation allows each component to perform its specific function optimally while reducing the harmful effects associated with single-pin suspension systems.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The coupling mechanism acts as an intermediary between the inner and outer socket assemblies. The disc-shaped adapter with its recessed interface mediates the connection, distributing loads and preventing direct contact that would cause wear and dirt infiltration in pin-based systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If conventional pin suspension is used, then attachment is achieved, but undesirable pressure transfer and pistoning of the residual limb occur

Engineering Contradiction:

Improveattachment strengthVSAvoidpressure transfer, pistoning

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The suspension system transitions from a one-dimensional pin connection to a multi-dimensional interface. The disc-shaped adapter provides a two-dimensional contact surface with the receptacle, distributing pressure across a larger area and eliminating the concentration of forces that causes pistoning and discomfort.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The coupling mechanism allows for dynamic adjustment and movement accommodation. The interface between the disc-shaped adapter and receptacle can accommodate residual limb movement while maintaining secure attachment, preventing the rigid pressure transfer associated with fixed pin suspension.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9161848B2Systems and methods for prosthetic suspension system

Publication Date: 2015.10.20 HANGER INC

AI summary

A prosthetic device includes an inner socket assembly including an upper interface member having a generally cylindrical outer periphery, the outer periphery defining a diameter and a length, the diameter being substantially greater than the length, and an outer socket assembly including a lower interface member having a recess correspondingly-shaped to the outer periphery of the upper interface member. At least a portion of the upper interface member is received within the recess of the lower interface member to secure the inner socket assembly to the outer socket assembly.