Viscoelastic Ferrule with Compression Spring for Crutch Impact Damping
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Solution Overview
Problem
Existing crutch ferrules do not effectively address the issue of crutch paralysis or crutch palsy, which arises from pressure on nerves in the armpit or axilla, and also fail to reduce wrist strain and carpal tunnel syndrome associated with crutch usage.
Innovation Solution
A shock absorbing ferrule with an assembly of at least one compression spring seated under a push plate within a socket, providing compression and damping during load application and decompression, and utilizing viscoelastic materials to distribute pressure uniformly, thereby reducing impact and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a traditional crutch ferrule is used, then the crutch provides basic ground engagement, but it causes high pressure concentration on the axilla nerves leading to crutch paralysis
Solution Approach 1:
The ferrule is segmented into multiple functional layers: a rigid outer shell for structural support, a viscoelastic intermediate layer for pressure distribution, and a shock-absorbing inner core. This segmentation allows each layer to perform its specific function while working together to reduce nerve pressure.
Solution Approach 2:
The ferrule employs composite materials combining rigid plastic for structural integrity, viscoelastic materials for pressure distribution, and shock-absorbing compounds. This composite structure maintains support capability while significantly reducing pressure concentration on axilla nerves.
2Stability of the object's composition
If a rigid ferrule is used, then the crutch provides stable support, but it transmits excessive vibration and impact to the wrist
Solution Approach 1:
The ferrule incorporates shock-absorbing materials and vibration-damping elements positioned to intercept and absorb impact forces before they can be transmitted to the wrist. This beforehand cushioning protects the user from vibration and impact during crutch usage.
Solution Approach 2:
The ferrule design changes the mechanical parameters of the crutch system by introducing materials with specific damping coefficients and shock-absorbing properties. These parameter changes reduce vibration transmission while maintaining overall structural stability.
3Object-affected harmful factors
If a soft ferrule material is used, then pressure is distributed better, but the crutch loses structural stability and support
Solution Approach 1:
The ferrule uses composite materials where a rigid outer shell provides structural stability and support, while an inner viscoelastic layer distributes pressure uniformly. This composite approach resolves the contradiction between softness for pressure distribution and rigidity for stability.
Solution Approach 2:
Different regions of the ferrule have different material properties: the outer shell is rigid for structural support, the intermediate layer is viscoelastic for pressure distribution, and the inner core provides shock absorption. This local quality variation optimizes both stability and pressure distribution.
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 shock absorbing ferrule effectively reduces the force per area on the crutch tip, minimizing pressure on nerves and reducing the risk of crutch paralysis and wrist strain, while also damping vibrations and rocking, thus providing improved comfort and safety for crutch users.
Implementation Method 1
a shock absorbing ferrule with an assembly having at least one compression spring, wherein the at least one compression spring is seated within a socket in the shock absorbing ferrule
Implementation Method 2
at least one compression spring, wherein the at least one compression spring is seated within a socket
Implementation Method 3
utilizing viscoelastic materials to distribute pressure uniformly
Implementation Method 4
providing compression and damping during application of a load, and damping during decompression of the load
Data Source
AI summary
A shock absorbing ferrule for a shaft of a crutch, an elbow/forearm crutch, a walker and other devices used during assisted ambulation, wherein the shock absorbing ferrule mitigates impact, potentially reducing injury during their use. The shock absorbing ferrule includes a ferrule having a viscoelastic walled cylindrical socket, which is an annular longitudinal cavity fitted with a shock absorbing assembly. The shock absorbing assembly includes at least one compression spring and a push plate. The compression spring has an outside diameter that is less than the inside diameter of the socket and is seated on the metal distribution washer and under the push plate. The push plate is a metal disk with a smooth perimeter edge having an upper side that is in abutment with an end of the shaft and a lower side that is in abutment with the compression spring.