Pretensioned Retaining Element for Prosthetic Joint Position Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Prosthetic joints, particularly in hand and forearm prostheses, often experience uncontrollable dropping due to lack of damping after the locking device is unlocked, leading to discomfort and unnatural appearance.
Innovation Solution
A prosthetic joint design featuring an elastically pretensioned retaining element that applies a holding force to the receiving device, allowing it to maintain position against gravity and enabling smooth adjustment and pivoting, with adjustable latching elements and a locking mechanism that prevents immediate collapse upon unlocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking device is used to secure the receiving device to the base, then the prosthetic joint can be fixed in position, but when unlocked the receiving device falls down uncontrollably due to gravity
Solution Approach 1:
A retaining element is elastically pretensioned against the receiving device to apply a retaining force before unlocking occurs. This preliminary action ensures that when the locking device is unlocked, the receiving device is gradually retained rather than falling uncontrollably, thus resolving the contradiction between position stability and control during unlocking.
Solution Approach 2:
The elastic retaining element acts as a cushioning mechanism that is already in place before unlocking. It absorbs the sudden gravitational force when the locking device is released, providing a controlled transition from locked to unlocked state and preventing harmful uncontrolled dropping.
2Reliability
If the retaining element applies a strong holding force to prevent dropping, then position stability is improved, but the receiving device becomes difficult to pivot and adjust
Solution Approach 1:
The retaining element is designed with elastic properties that allow it to dynamically adapt its holding force. When the receiving device is stationary, the elastic element maintains strong tension to prevent dropping. When adjustment or pivoting is needed, the elastic nature allows temporary relaxation of the holding force, enabling easy movement while maintaining position stability during use.
3Ease of manufacture
If the retaining element is designed as an elastic band for simple production, then manufacturing ease is improved, but wear and service life are reduced
Solution Approach 1:
A contact part made of hard or wear-resistant material is introduced as an intermediary between the elastic retaining element and the receiving device. This mediator transfers the retaining force while protecting the elastic band from direct wear and friction, thereby extending the service life of the retaining element while maintaining production simplicity.
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 design prevents uncontrolled dropping of prosthetic devices while maintaining adjustability, enhancing user comfort and natural appearance, and can be adapted for various applications including motor-driven prostheses to reduce energy consumption.
Implementation Method 1
A compression spring 59 is arranged in the base 2, which acts on the locking device 5 with a restoring force
Implementation Method 2
a retaining element (6) is elastically pretensioned against the receiving device (4) and applies a holding force to it
Data Source
AI summary
Prosthetic joint comprises a retaining element (6) which is pre-tensioned against a holding unit (4) using a holding force. Preferred Features: The retaining element is pre-tensioned so that the holding unit is held in a locking position against the force of gravity. The holding unit has locking elements (416) for the retaining element. The locking elements are formed as recesses, notches or protrusions.