Remaining Mobile.

Over the last few years Parkinson’s Disease has made it increasingly difficult for me to carry my photographic equipment any distance.  I was diagnosed in 2011 and as recently as 2015 I was carrying a 20 kg rucksack all day over all kinds of terrain, but then I started loosing coordination in my left arm and the difficulty was not so much carrying the rucksack as getting it on in the first place!

So I started casting an eye about for some means of carrying my gear, and eventually I bought the Monowalker.  Designed for moving over rough ground, it is hitched to a harness a little like Scott’s method of man-hauling sleds!  I used it without the harness (like a posh wheelbarrow) and it worked very well, although kissing gates and stiles presented a problem as I had to unload and reload it either side.   However, towards the end of 2017 I was starting to have difficulty pushing or pulling it, and a new solution was needed.

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The Monowalker loaded up for a night time trip.

I looked at some electric trolleys, mainly designed for fishing, but these had various drawbacks.  They were generally big, heavy, and even secondhand ones were expensive.  More importantly they would be difficult to modify them for carrying my camera gear.  Then I hit upon the idea of converting an electric golf trolley.  This was far more promising as they were light, folded up for transportation and had a good range.  The big plus was that they would be easier to modify.  After looking at many different kinds I eventually bought a secondhand ‘GoKart’ trolley off eBay for £50, and set about modifying it.

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The ‘GoKart’ golf trolley before modification.

First I needed some method of securing my camera equipment, including the time-lapse motion rail.  The first idea used four lengths of Unistrut fixed across the frame, but this added too much weight and was probably a bit of  over-design on my part.  After a little more consideration I designed and fabricated a timber bed with a toe board and a cut out for the battery.  This was fixed to the frame using ‘U’ bolts and has lashing eyes fitted for securing the equipment.  It is also split so the trolley can still be folded.  Initial trials of this went well, but revealed that the trolley was going to need bigger wheels if it was going to traverse rough ground.

I bought a pair of 20 inch bicycle wheels with disc-brake hubs, but in order to get these to fit I was going to need to replace the existing trolley drive shaft wheel hubs.  I designed new ones using Autodesk Fusion 360 and the resulting models were used by a friend (Daniel) to fabricate the hubs from aluminium.

 

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The new hub design. The grey part is the drive shaft spigot, the blue part is the wheel hub adaptor.

The new hubs were in two parts. The first, the drive shaft spigot, was designed to replace the originals, and fitted the hexagonal socket in the trolley’s drive shaft.  Once screwed in place the spigot end was left projecting onto which the second piece would slide.

The second piece, the wheel hub adaptor, was bolted to the wheel via the disc brake fixing hub, and would slide over the trolley’s drive shaft spigot.  It was then secured using a large spring pin.  This arrangement meant I could remove the wheels for transportation and storage.

My principle concern was that the change of driving ratio due to the bigger wheels would mean the trolley would go too fast.  (I had visions of me chasing it for miles along some Scottish beach!!!)  I couldn’t do anything about the gearing as the gearbox is an integral part of the drive train.  All I could do was hope that the slowest speed was slow enough !!

However, my fears have proved groundless.  For its first trial I took it down to New Brighton beach so I could do some time-lapse work. It all went fine and when it started to struggle in the softer sand I just fed a little more power to the wheels. I’ll have to be careful how I load it up as the balance point is over the wheels but it works a treat.  There are a couple of minor changes to make and I’m sure it will continue to be improved.

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The finished item.

I have a long-term time-lapse project planned and the trolley is key to getting my gear to where it is required. This will test it’s abilities (as well as mine!) but for the time being I’m still mobile!

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