A seminal paper… published in 1956
Back here I described my search for the lightest possible springs for a lightweight human-powered vehicle. Although I didn’t say so at the time, it had been my desire to use rubber – light, cheap and readily available.
However, as that article describes, I found it impossible to find a rubber (or elastomer) approach that allowed high spring deflections without overstressing the rubber. High suspension deflections were possible with rubber, but in turn that required high motion ratios (ie leverage) that resulted in large stresses in the suspension arms and spring seats.
However, since writing that article in 2007, I have been reading everything I can find on using rubber as suspension springs – and I have to tell you, there’s not a lot around.
But today I found a paper that I think is worth sharing with you. I can’t share the content – it’s copyright – but I can say it’s the best treatment of using rubber as vehicle springs that I have seen. It was published in 1956 and the author is Alex Moulton, the man who later developed the rubber springing used in the Mini, and the rubber-and-fluid suspension used in the Mini, Austin 1800, Morris 1100 and other vehicles.
You can buy the paper from the Institution of Mechanical Engineers Proceedings Archive here – it will cost you US$30.
If you are interested in lightweight vehicles with sophisticated suspension design, I think it’s a must-read.
on November 3rd, 2011 at 3:19 pm
Moulton also designed and produced a range of small wheel bikes with rubber suspension in the mid-1960s, and I think he created those rubber suspension units used on trailers and some of the 1950s-60s micro cars/3 wheelers (had them on my Bond Minicar).
on November 6th, 2011 at 1:22 pm
In the ultralight aviation world, some use bungee cords as spring. When setup as a push/pull rod, it works well and lightweight too
on November 7th, 2011 at 8:13 am
He still makes the bikes http://www.moultonbicycles.co.uk/
The web site contains information about the design philosophy and technology.