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4 Ingredients For Perfect Prosthetic Hands And Arms

Updated: Feb 15, 2023

ExpHand prosthesis holds the hand

With an increasing number of prosthetics companies in the market trying to convince customers that their prosthetic hands or arms are revolutionary devices, parents of children with limb differences may find themselves more lost than ever in a sea of different technology and information - each company or piece of literature having their own ideas of how a given innovation or piece of tech replaces a human limb or digit, without clearly explaining how it works.

However, ExpHand are daring to be different. In this little corner of our site we'll share with you how our prosthetic hands and arms work, how they create the movement and functionality that they deliver and how they replicate the movement and functionality of a biological finger, wrist, hand or arm. We'll also take you behind-the-scenes, and show you what goes into making prosthetic hands and arms for children - from how we introduce motor functions in the prosthetic to how its design ensures practicality in a bunch of different real life situations. Without further ado then, here are 4 elements that make an ExpHand device suitable for your child's needs.

Ingredient 1: Elastics and strings that take over muscle and tendon activity

In theory, replicating muscle and tendon signals seems like a tough mission. But if we look at them purely from a science based perspective, we realise that they are merely elastic strings that move various body parts.

This means that effective use of elastics and strings allow prosthetic hands and arms to copy muscle and tendon activity, allowing things like prosthetic fingers grip around objects and then pull back to their natural open position. By adjusting the elasticity of the strings in our prosthetics, we can control the force needed to move the fingers to the desired level.

Ingredient 2: Pulleys that make it easy to move your fingers

There is one issue though! Simply adjusting the elasticity of the strings is not enough to make the ExpHand as practical as we would like. This is why we added a pulley system (yes, the same one from your year 7 physics class) to ExpHand prosthetic hands - the presence of the pulleys further decreases the amount of force required to move the fingers.

Ingredient 3: Straps that ensure that the prosthesis is easy to use

One of our main goals when we designed the ExpHand, was to create as much leverage as possible to make the prosthetic a breeze to use. By rule of thumb, the less leverage there is, the harder it is to make something move.

Our solution was to use multiple straps below the elbow which ensure that we are pulling from as far away from the elbow as possible. The mechanism gave the ExpHand an optimal amount of leverage, and makes it easier for little children to handle with ease.

Ingredient 4: Materials suitable for any environment

Our skin is not only our biggest organ, it's alsoan engineering miracle only mother nature could create. Just think about it: our skin allows us to connect with and learn about the surrounding environment, it is strong enough to withstand most weather conditions, and continuously repairs and regenerates itself. How could an artificial material begin to replicate all these functions?

When they are young, children want to touch, pick-up and play with as many things as possible. Since prosthetic hands and arms are used in lots of different situations and conditions, we needed to find a durable, 3D-printable material that also felt nice to touch.

PLA is a plastic that meets all of the above criteria and more. Whether it's hot or cold, wet or dry, prosthetic hands and arms made of PLA stand the test of time. The fact that the material is widely available also allows us to keep our production costs to a minimum and means we can make the ExpHand accessible to everyone, regardless of income. It is also biodegradable, meaning that old prosthetics can and will be recycled or repurposed.

In conclusion

These 4 ingredients make the biggest difference when it comes to integrating a prosthetic device into children's daily lives. True, there is nothing revolutionary about elastic bands and pulleys, but their use in prosthetic hands and arms is life-changing, and we're proud to play a part in that.

Further support from ExpHand

For the latest news and insights regarding the design of prosthetics for children, as well as inspirational stories from the limb difference community why not check out the ExpHand blog? Or alternatively, if you have questions about prosthetic design or life with a limb difference, you may find your answer in our FAQ too.


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