Bicycle handlebar adaptation
The client is a keen cyclist and would like to take part in the coast 2 coast cycle ride for charity. However, her left hand stops at the wrist making it difficult to hold onto the handlebars, especially when rising out of the seat for uphill climbs. The client had tried various strap-on arm attachments but did not feel safe as they left her attached to the bicycle in the event of a fall. She wanted a way of holding the handlebar more securely but with the ability to let go quickly in the event of a crash or fall.
The Challenge
The client has a limb difference, her left hand stops at the wrist with small fingers that have no bones or muscle control. This leaves her unable to grip the handlebars of her bike with her left hand.
The client would like to be able to grip the handlebars of her bike to aid cycling without being strapped to the bike, which she feels would be dangerous in the event of a crash or fall.
The client had tried commercially available prosthetics but felt unsafe when cycling with them as they would leave her attached to the bicycle in the event of a crash.
The challenge was to create a way that the client could grip the handlebars during normal riding whilst still being able to quickly release this grip in the event of a crash or fall.
The solution
To ensure that the prosthetic would fit precisely, a 3d scanner was used to create a 3d model of the client’s arm and wrist area.
The resulting model was then modified to provide a comfort clearance space for the fingers to ensure they didn’t get squashed. This model was then 3d printed at 105% scale to provide the hand mould required for the prosthetic.
Next, a 3d printable holder was created that could be firmly attached to the clients existing handlebars. This provided a void into which the hand mould was suspended. A 2-part silicone was used to fill the void between the hand mould and the handlebar holder.
The silicone material takes around 4 hours to cure and once set the hand mould is removed from the silicone and the opening trimmed to make it look neater.
Finally, the captive nuts are fitted to the holder and the completed prosthetic is fitted to the client’s bike for trials
In all, three versions were made with the main differences being the addition of more free space around the fingers, more room for silicone padding near the main contact points and additional nut & bolt fixing points to secure the holder to the handlebars.
The benefit
When the client saw the first version and placed her hand in it she became quite emotional. She said that she had never had something created that fitted her own hand before!
After her first cycle ride of around 15 miles the client said they were able to remain in good control of the bike even when rising out of the saddle to help power up the hilly sections.
In a followup call a few weeks after receiving the final revision the client said that she had “been out loads and loved it”.
They had even been using it to cycle to work.
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Thank you Adam. Please contact me if you know of any other people that could benefit from this type of solution.
As a cycle enthusiast, I think this is a genius, yet simplistic invention. Glad the client got to accomplish the coast to coast fundraiser!
Thank you, Adam!