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The idea was to create a self-propelled wheelchair that can be used as a wheelchair, a rollator, a transit chair or just simply somewhere to sit.
Mark Whitfield
Introduction
Axle Pin Plate
40 x 40 T-Slot Profile Attachment
Design Brief
Design a device which would act as an axle quick “release pin” holder. The Axle pin has two bearings which are operated by depressing a button on the head of the axle pin. The axle pin plates must be able to withstand pressures created by the weight and movements of the wheelchair, the user, and steep lateral gradients, rough and uneven surfaces, possibly off-road terrain.
The dream.
To create an axle pin plate that could fit a that could fit a wheelchair with a frame constructed from 6063- (40mm x 40mm) aluminium t-slot profile.
The end product.
The end product is (2x) 120mm x 120mm x 10mm cast aluminium plate. Wach plate has been designed to be attached to a single profile or across two profiles. Spacers are used to ensure a safe distance to moving parts as well as compensating for different axle pin lengths depending of the type of wheel used.
The problem.
Finding a suitable material and how to fit it to the wheelchair frame. To test the ideas, multiple models were 3-D printed. The models were then tested for strength and practicality.
The benefits of this design
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Axle pins of different lengths are readily available from on-line shops.
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Aluminium or stainless-steel bar is available from on-line stores, cut to size, (if required)
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Light weight
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Inexpensive materials
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Low-cost production as the design and G-Code for the (9x) M8 holes and (1x) 12.3mm hole for precision drilling or milling on CNC device can be written at home.
My Process
Being a wheelchair user, I have spare parts which aid me in repairing my wheelchair. I decided to use a larger axle pin with spacers to allow for the different hub sizes for different wheels I use. After 3-D printing several different forms of the plates, I tested the plates by fitting them to t-slot profile, then attached the wheels. It became apparent that the design was good, but would require strengthening. I used a 28mm (OD) x 21.8mm (ID) round aluminium tube, as a sleeve for a 21mm (OD) x 12.8mm (ID) round aluminium tube, the housing for the axle pin. Although over-kill, the design is strong.
About me
Being a disabled veteran and as a former plant operator mechanic, I have always enjoyed designing and constructing things of use. T218 was my first design module, and sadly the end of my studies. I have had a great time and have enjoyed making this journey.