You guys are great. 
I am not sure what the prosthetist has come up with yet, but it sounds like it is similar to what Rikk has described - J's next appointment isn't until next week so we'll let you know.
There's a photo above that gives you an idea what shape is left. Basically though, it's just his ribcage with a layer of skin over it. That's apparently the problem - there are no lumps or bumps to 'secure' anything to, so the strapping has to be around his torso quite firmly - but not so firmly he can't breathe when he is riding.
Where are you guys based - this sounds very much like it needs a night in the pub with beer and lots of paper and pencils...
Chat Forum
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For those interested parties (one armed rider update)
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Posted 2 years ago #
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if your going to a university, our penultimate year mechanical engineering project was a group (4 or 5) effort with 3 or 4 different projects in the year so there was atleast 4 or 5 other groups doing the same. Obviously this depends on the Uni's curriculum
I think something like that would be an excellent start, leaves scope for developing further and you may get a few workable solutions.
Posted 2 years ago # -
Why not look at building it into something like this
Also if the connection point is just below the collar bone the majority of forces would just be pushing against it or pulling away as it extends.
Built into a torso protector like the one above it would spread the load evenly without it all going through one or two strapsPosted 2 years ago # -
TN - I am Edinburgh based. I am still pondering this and will post again if I come up with any more ideas
Does he have anything left of the shoulder? Collarbone? / shoulder blade?
I am guessing braking is the biggest issue - staying stable on the bike or does whatever "arm" attachment need to be able to be used for bracing in other directions?
Posted 2 years ago # -
If you contact me by email i would happily call the guy i mentioned earlier to talk to you. He already has a prosthetic riding arm designed for the job so will probably have quite a lot of relevant info. He is also the guy who has some rather neat solutions regarding braking systems etc.
Posted 2 years ago # -
TJ - there's nothing left of the shoulder - well, about an inch of collarbone but no shoulderblade. It was a biggie....
The main need for stabilisation is indeed when braking and/or going downhill. It is difficult for him to shift his weight back easily and brake and remain stable/supported.
I keep trying to work out 'better' riding positions for him - I know my 'extra' weight on the left means it's not an accurate test, but it really is quite tricky to do it. I tend to shift left on my saddle and wedge my left knee into the cross tube with my right leg and pedal forward and 'braced', but it is a bit of an unnatural position to be in and is difficult to move easily from should you need to, while still going downhill. (does that make sense?)Posted 2 years ago # -
Rikk, we have motocross armour jacket which we thought we could maybe modify but it's not 'sturdy' enough to work - we can look at others though.
Another further spanner in the works is that because he has lost quite a large surface area that he can sweat from, he overheats more easily than he used to. So we have to be careful how much of the remaining surface gets covered, or there has to be lots of ventilation...
(Not something we even considered until the surgeon pointed it out!!)Posted 2 years ago # -
Regarding the sweat issue, obviously drink lots but also pop something like nuun tablets in the water to replace the electrolytes, not sure if he's tried one but buy a buff and wear it under the helmet it keeps you cooler and also stop the sweat dripping in your eye's
With regard to fixing, don't try and fix something to where the shoulder used to be, try fixing to the pec muscle so the forces are pushing into the body.
I found it's easier to think about the problem working out whats needed to sort it rather than try to replicate how the body did it.
When i finally get sorted with work I'll draw something up.Posted 2 years ago # -
With regard to fixing, don't try and fix something to where the shoulder used to be, try fixing to the pec muscle so the forces are pushing into the body.
This is what I was thinking of - then it just needs to be secure enough not to slip rather than secure enough to hold all the forces.
Posted 2 years ago # -
Yep thats the idea
Very simple to then hold in place, so you have a small fiberglass plate over the pec to take the force and join the air spring to, coming off the plate you'd need two arms one to go around the side of the rib cage and 3-4 inches towards the spine and one going over the shoulder. If that is built in or attached to a nice open torso protector it will stay in place quite happily.
Once he's used that for a while you could experiment with another joint as an elbow and move from the air spring to cheap bike shock to pickup the movement at the elbow, as it would still effectivly just be pushing into the pec it should work just as well. The you can do funky things like having a shock with a platform on off so when cycling on relativly flat places you effectivly lock the shock out but when hitting the rough stuff turn off the platform damping for more movement.
BUT, better to start off simple and add things as you go than aim for the sky and constantly fail, little steps see what works and build on them.Posted 2 years ago # -
J saw the prosthetists yesterday and here is riding arm #1.
It consists of a modified shoulder cap with a socket in the 'shoulder joint' area.
The arm clicks into that and locks.
The elbow is a fixed but adjustable joint, lockable in about 5 different positions, so it is fairly manual but he can adjust it to be straighter when he's going downhill, or more bent/shorter for on the flat.
The 'wrist' end clicks into a socket on the handlebar. I am not sure whether there is an 'emergency release' on this joint - I suspect not, and I'm not entirely happy if that's the case, but it's a prototype so we'll see.
He has only ridden laps of the hospital carpark so far but we have a gentle ride planned for the weekend (prosthetists orders - nothing too testing!!) and I have orders from J to take lots of pics and to film him, so I will post them too.(problem posting picture - will try again...)
Posted 2 years ago # -
Posted 2 years ago #
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back in the early 90's there was a chap that had a prosthetic arm made up for mtbing and it featured a titanium Girven Flex Stem (remember them) as the elbow..
must be some pics somewhere.
Posted 2 years ago # -
Cool. I was wondering how he was getting on.
Posted 2 years ago # -
Blue and green anodising? I hope later prototypes are more colour coordinated! I suggest black and gold.
Posted 2 years ago # -
Thanks TJ.
PP - I know, I know, Some people just have NO colour sense whatsoever, do they. Mind you, I DO like the little red cuff on it. I was hoping for a bit of carbon fibre at least.
Will post action shots and possibly video later (but if I can't post pictures I don't really stand a chance, do I? In my defence, I just 'upgraded' to IE8 and I think that's the problem.)
Posted 2 years ago # -
A chap here at work once rode with a bloke with no hands. He had a ball-joint arrangement where the balls were on the end of his arms and slotted into the bars. Not sure how he worked the brakes.
Posted 2 years ago # -
We went for a ride yesterday with the new arm. We rode a local route so he could compare how it felt without and with the arm. The weather was grim though - we ended up with head winds up all the climbs, but the terrain was fairly challenging with lots of slidy and gloopy mud/cow or horse poo, unavoidable puddles and wet rocks.
We have a list of things that could be improved but on the whole it went quite well.
Photos to follow - having some trouble uploading them.I ended up having to cut an inner tube up and lash the 'hand' bit to the bars because every time he leant back it popped out. That helped quite a lot.
And the shoulder joint lock is too easily caught so he ended up with his arm dangling from the handlebar at one point, which was a bit frustrating...
Also the fixing point at the shoulder it too low (which I thought initially but until you test it you can't say for sure, can you?)
The locking elbow is a drag because every time he gets to the top or bottom of a hill he has to stop and reposition it and relock it.BUT, he said it definitely gave him some extra confidence and stability. He rode one of our usual downhill bits MUCH quicker than I have ever seen him ride it and with no dabs.
(He said that was partly arm and partly after we rode Rushup Edge - he said that's boosted his confidence a lot which is cool. )
It looks like a damper/shock of some sort is going to be necessary because the multi-position lock out at the moment isn't working well. The prosthetists are well out of their comfort zone though so I think this may end up being a home project.Will post photos soon.
Posted 2 years ago # -
Still can get pics to post
Click herePosted 2 years ago # -
Pictures
Go on to all sizes, right click / properties / location and paste into box that appears when you click img in the reply box
Posted 2 years ago # -
Thanks again TJ.
I wasn't doing the 'all sizes' bit - I was just clicking on the 'thumbnail' to open the pic and then taking the location properties from the larger version that opened. I will try again in a bit.
I also have video to post, but I can't even get that to upload to flickr yet so I don't fancy my chances much...
(Is this where I admit I am supposedly a techie?)Posted 2 years ago # -
Hi TN
Thank you for this great story. I remember talking to a chap earlier this year at a XC race about his Yeti ASR. This dude was racing on the day and he also had a missing arm. He had a curved pincer type prosthetic fore-arm. I never asked him about how he managed , just talked bikes.
Well done to your mate and as someone said at the beginning of this thread, 'Who needs an arm if you have Balls...'
I am sure that a better solution will be found with a bit more Research and Development.
Best of luck.Posted 2 years ago # -
Was at Delamere yesterday and there was a chap there with one arm (still had the other arm but obviously did nothing). Looks like he had an adapted road bike - hugely impressive, I have enough problem with two arms
Posted 2 years ago # -
I was thinking about something wouldn't it be worth getting a gravity dropper?
It will indeed help in the down, plus he could hole the saddle between his tights to help directing the bike.Plus I concur with peter
it has to be black anodizing Posted 2 years ago # -
I ended up having to cut an inner tube up and lash the 'hand' bit to the bars because every time he leant back it popped out. That helped quite a lot.
Sorry TN - i'm not sure what movement J can impart on the riding arm but - having read the above I was wondering if there is anyway the arm and bar mount bracket can be adapted to take some sort of SPD clip in type system - compact enough and hopefully enough to hold in place when needed - and also release when needed!
Just a thought
Chris
Posted 2 years ago # -
Heard about this bloke last week - amazing riding shots. Going to point a few of the well it has to be improved because its increasing access for all people in the direction of these pics.
Posted 2 years ago # -
Chris, I am not sure (certainly with the current version of the arm) whether he'd be able to produce the motion required to clip out of an SPD-type arrangement, but it is certainly worth keeping in mind.
I think now he's tried this version we can look at ways to improve it - it's good to have a starting point.
To that end, he's currently watching various air shocks on 'that auction site' with a view to trying one of those instead of the current elbow arrangement. We figure if he can provide the part and some drawings, the prosthetics guys should be able to put it together. And if not, we know a fair few mad inventor types...One interesting side effect was that after he had been riding 'with 2 hands' his phantom limb felt different - less cramped up and uncomfortable. I have heard people report that using a prosthetic can improve phantom limb pain but it was cool to see it in action. It didn't last long but he said it made a nice change.
Posted 2 years ago # -
I read about this therapy for phantom limb pain where they sat people next to a mirror so they could see their real limb reflected where their missing one would be. Their brain then sees two limbs and sorts itself out. One guy had been 20 years feeling that a missing hand was clenched painfully tightly, then he used this mirror, unclenched his real hand and that was it - pain gone.
Posted 2 years ago # -
Molgrips - mirror box therapy is pretty amazing, isn't it? It's kind of tricky for J because the 'standard' set up is to put the residual and/or phantom limb inside the box on one side and the remaining limb in the other side. Unfortunately J has no residual limb and he can't move his phantom to place it as though it were in the box, so it doesn't work for him at the mo. Maybe if the phantom moves in the future though...
It's a pity because it sounds like it does great things for those who can use it. Weird how the brain works though, isn't it?The riding arm is progressing though now - 18bikes are looking into couplings to allow him to fit an air shock to the limb he's got so that he has a dynamic 'elbow' rather than one he has to lock in position. If that works it should improve things even further. Watch this space...
Posted 2 years ago # -
And here's another pic, just because...
Posted 2 years ago # -
Still looks like there's very little weight on the new arm tho..
But still - brave riding on the snow and ice like that
Posted 2 years ago #
Topic Closed
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