Body-Powered Hand Prosthesis With Time-Delayed Grip Release
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Solution Overview
Problem
Existing mechanical hand prostheses lack time-controlled movement functionality without the use of electronics, motors, or sensors, and require active intervention for grip release.
Innovation Solution
A purely mechanical self-powered hand prosthesis with a winding and gripping device that includes winding means and gripping means, allowing for a time-delayed return of the thumb joint to an open position without electrical aids, using mechanisms like spring returns, shape memory polymers, or pneumatic/hydraulic systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a motor-driven prosthesis with sensors and control devices is used, then the grasping movement and release can be precisely controlled, but the device complexity and cost increase significantly
Solution Approach 1:
The patent extracts and removes all electromechanical components (motors, sensors, control devices) from the prosthesis system, retaining only the essential mechanical elements. The core function of automatic grip release is achieved through a purely mechanical return mechanism that eliminates the need for complex electronic control systems while maintaining the automated release capability.
Solution Approach 2:
The prosthesis is designed to be self-powered through the user's own body movements. The mechanical return mechanism automatically resets the gripping device after use without requiring external power sources or electronic control. The system serves itself by converting the user's natural movement into the energy needed for both gripping and automatic release.
2Ease of manufacture
If electromechanical components are removed to simplify the device, then the prosthesis becomes more robust and easier to manufacture, but time-controlled movement functionality is lost
Solution Approach 1:
The mechanical return mechanism is pre-configured with a defined travel path and resistance characteristics that automatically determine the duration of the grip. By designing the mechanical geometry and spring constants in advance, the system achieves time-controlled movement without requiring electronic timing circuits or programmable controllers.
Solution Approach 2:
The patent employs pneumatic or hydraulic elements (such as rubber bands or air springs) to provide controlled resistance during the return movement. These fluid-based mechanisms offer smooth, time-controlled deceleration and positioning without the complexity of electronic control systems, enabling the grip to be maintained for a predetermined duration before automatic release.
3Reliability
If a purely mechanical return mechanism is used, then the prosthesis becomes lighter and more reliable, but the ability to maintain grip for a defined period is compromised
Solution Approach 1:
The mechanical return mechanism is designed to execute a periodic cycle: the user's movement winds the spring or compresses the rubber band during gripping, then the stored energy automatically drives the return movement after a defined period. This periodic mechanical action creates a natural timing mechanism that maintains the grip for the required duration before automatic release, eliminating the need for electronic timers.
Solution Approach 2:
The system controls the timing of the automatic return by changing physical parameters of the mechanical components - specifically the spring constant, rubber band tension, or air pressure. By adjusting these parameters, the duration of the grip can be precisely controlled without adding electronic control systems, maintaining both reliability and time control through mechanical means.
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
Enables a mechanically robust, lightweight, and cost-effective hand prosthesis with automatic grip release after a defined period, suitable for sports activities like tennis or badminton, without the need for batteries or microcontrollers.
Implementation Method 1
a winding means (E1) and a gripping means (E2), wherein the winding means (E1) and the gripping means (E2) are mechanically coupled to one another
Implementation Method 2
using mechanisms like spring returns, shape memory polymers, or pneumatic/hydraulic systems
Data Source
Figure 1~2b
Figure 3a~3b
AI summary
The invention aims to provide a mechanical body-powered hand prosthesis (D) comprising a raising and gripping device (E), wherein the raising and gripping device (E) has a raising means (E1) and a gripping means (E2), such that, once the raising means (E1) has been actuated, a joint (E3) can be moved towards a palm (D1) by means of gripping means (E2), wherein electromechanical components are dispensed with and a simple, purely mechanical, cost-effective production is thus achieved. This is achieved in that the raising means (E1) and gripping means (E2) are integrated in the body of the body-powered hand prosthesis (D) and interconnected so as to act purely mechanically, and in that the raising means (E1) have a return mechanism (E11) such that a raising lever or raising wheel can bring about a deflection from a neutral position into a raising position and, in the process, a deflection of the gripping means (E2) and thus a joint (E3) into a closed position for carrying out a gripping process, the gripping means (E2) remain in the raising position for a defined delay period (III) and the raising means (E1) allow the gripping means (E2) to return to an open position only after the delay period (III) has elapsed, as a result of which a gripping process is provided that is maintained in a temporally defined manner.