How to stiffen this flexible thing?

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  • How to stiffen this flexible thing?
  • The title wasn’t deliberately vague. I’m not sure about the correct terminology.

    I’ve butchered a desk iPad stand to make this for one of my students. He’s pretty much non-verbal and uses an iPad to communicate.

    The flexible rod is, I assume, some kind of coiled metal around a core of ‘stuff’*. It works brilliantly and being able to adjust to position of the iPad for his motor abilities on a given time or day is fantastic. The problem I have is that as the wheelchair is bumped around, the iPad slowly lowers itself down and needs to be moved back to the correct position every 15 minutes or so. Not the end of the world but not ideal.

    Because of the boys motor problems, he can’t move it to the correct position by himself.

    It would be great if I could somehow stiffen the ‘thing’. Could it be sleeved in something? I have C9 and duct tape and access to the school’s DT rooms.

    Any suggestions?

    Thanks

    *let me know if I’m getting too technical.

    Premier Icon molgrips
    Subscriber

    Wrap it in a bandage soaked in some kind of resin…? Give it a few layers.

    Experiment on something else first though.

    stumpy01
    Member

    First thought is that the large bend outwards just above the foot rest assembly of the wheelchair means that the weight of the tablet is always going to cause it to droop forwards over time.

    As a first attempt, I would be tempted to get some thin aluminium (2mm sheet or thereabouts) and form a stiffener for that bend. You could draw a template of the shape & try to bend to that; then just zip-tie it in place (for trial purposes) – put some holes in it for the zip-ties to pass through.
    You could do a similar thing for the bend further up that brings it back to a more vertical path.

    You would still have flexible parts in between that would provide some adjustment & hopefully these would be less inclined to droop as the major curves are held in place.

    You can get thin strips of aluminium from places like B&Q – our local one has a large section of random alu sections in the same aisle as the fasteners & rawl plugs etc.

    Premier Icon martinhutch
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    The cheapest fix would be to get a length of thin steel rod and bend it to match the first couple of feet of the cable (past the bit where it leaves the leg), then zip tie it on. You’d still have plenty of flexibility in the upper part.

    revs1972
    Member

    As per stumpy01 suggestion, however, if you have access to C9 then substitute this for the aluminium parts.

    Premier Icon on and on
    Subscriber

    I’d be tempted to try some heat shrink over the bendy bit if you can get the ends off.

    I’m with martinhutch – the flexible section is too long so being top-heavy there is no way it will hold without replacing or bracing/strengthening the lower 24 inches or so.

    Steel rod is potentially dangerous though, especially if a fall occurred. I’d use a couple of feet of blue plastic water pipe (or similar, check diameter) to sheath the bottom section, use heat to bend pipe so matches the existing angle of the flex.

    Premier Icon wwaswas
    Subscriber

    look at tube bending springs maybe?

    http://www.screwfix.com/p/bending-spring-25mm-black/83372?kpid=83372

    They’ll stiffen the tube up while remainign flexible and also not be a hazard as they won’t bend far enough to open up and catch fingers.

    Not sure on the length of that example or the diameter of the tube on the chair already so you may need to visit a plumbers merchants or somethign to get the right thing?

    [edit] it may be they want to ‘strighten up’ too much to retain the shape you want though?

    Premier Icon martinhutch
    Subscriber

    potentially dangerous

    My USP when it comes to design. 🙂

    petrieboy
    Member

    how about wrap as much of the lower section as you can get away with in carbon fibre to lock it into position?

    Premier Icon nedrapier
    Subscriber

    I’d use a couple of feet of blue plastic water pipe (or similar, check diameter) to sheath the bottom section, use heat to bend pipe so matches the existing angle of the flex.

    My favourite.

    Thanks for the replies.

    The ‘droop’ is down towards the left-hard arm rest. It isn’t fore-aft but left-right. The problem is is that the droop seems to be happening just above that upper clamp. The shape of the ‘pole’ stays the same.

    I’m in Thailand. I have access to everything suggested so far (glass fibre as opposed to carbon wrap) and plentiful supplies of the blue plumbing pipe.

    “the flexible section is too long so being top-heavy there is no way it will hold without replacing or bracing/strengthening the lower 24 inches or so.”

    It would be great to stiffen the bottom without making it rigid. I’d say the ‘pole’ could be shortened about 10cm without compromising the usefulness of it.

    sharkbait
    Member

    The cool solution would be to get some carbon tape, epoxy resin and some shrink tape.
    The it in the right place and then wrap with carbon tape, wet it out with epoxy (you could wet the tape out first before wrapping if you like) and then wrap it all in shrink tape and apply heat. Leave it overnight.
    The next day remove the shrink tape and bask in the glory of your custom carbon iPad support.

    The less cool solution would be to wrap it all in plenty of black gorilla tape. 😉

    Edit: Looks like most of the weight is just above the clamp, for either of the above I’d wrap the lower half to start with leaving the top free for adjustment.
    Obviously you’d need to wrap all the way to the bottom and if using duct tape consider bending some metal to support the bend above the clamp.

    Making a tubed version with carbon/grp tubes and universal joints would make a great DT project for the kids

    this looks better:

    Or this? – (bonus alien-tech looking)

    http://www.cheapdisabilityaids.co.uk/flexzi-3-with-ipad-case-9523-p.asp

    globalti
    Member

    I believe the coiled thing may be hollow, in which case you could slip a metal rod inside it. Best would be a length of copper 7mm or 10mm heating pipe, which will stiffen the whole thing yet remain flexible and hold its shape.

    I’ve got some in the garage, which you could have if you happened to be nearby in Lancashire.

    It does Malvern but, the child is just 7. He can crawl (not walk) and so needs to be lifted out of his chair. Something like that (attached on both sides) means he needs to be lifted up and back. I can manage but the TA and other staff can’t. At this age, he;s in and out of his chir 5-10 times a day. Because of the design of his chair, those clamps wouldn’t work. There’s nothing solid to clamp it on to.

    I’ve made something like this before but attached to the chair. Removing it was a 10 minute job and needed a spanner. Not ideal and it really blocked him off from the world. Being able to push the ipad out of the way is great.

    His parents are wonderful but aren’t as behind AAC (using the iPad to communicate) as I and the school are. That looks like several hundreds of dollars of bendy stuff.

    @globalti – We’re in Thailand. Plenty of access to stuff like copper in various diameters. Kind of you to offer though.

    Premier Icon theotherjonv
    Subscriber

    Is a second (or third) flexirod ziptied to the first one too obvious a quick fix?

    OP, gotcha.

    The second one is clamped on one side and is £90. Check it out?

    Fund-raising and offer of shipping at the ready if it would help – but if you fix it DIY and safely then that’s obv the best immediate option I agree.

    There are shorter snake-flex solutions (like yours yet fixed by clamp to the tubular arm assembly of wheelchairs), have you looked into those/modifying as per? Shorter is stiffer, so they say!

    sharkbait
    Member

    You could also just attach another ‘bendy thing’ to the first one – that would stiffen it up.
    Hose clamps would work.

    Or one of these for $60 shipped (maybe not to Thailand though 🙁 )

    Three_Fish
    Member

    An L-shaped curved length of plastic pipe with a bit of resistance where it’s clamped to the frame of the chair. Even a threaded handle to clamp it. Either way, that’d mean there’s nothing in front of his legs and the hole thing just rotates out of the way when the lad needs to exit the chair.

    sharkbait
    Member

    If you could get hold of a short piece of electrical cable (proper heavy stuff) you could strip individual wires out of it and wrap them around the existing flexithing, and then duct tape.

    Premier Icon kayak23
    Subscriber

    Milliput epoxy putty is great.
    Roll it into sausages and squidge it against the part that you want to stay rigid, and in 20 minutes it will…
    Lots of fun colours too.

    “You could also just attach another ‘bendy thing’ to the first one – that would stiffen it up.”

    The correct answer is so obvious!

    Earlier I meant to post an image of the previous “solution”. It’s something like below but attached to the chair. There are a few flaws with it though.

    It’s there permanently (20 min job to remove)
    Getting him in and out of the chair is a pain with it on.
    The CoB moves way forwards. On the verge of dangerously (not my USP 🙂 )
    It’s a physical and literal barrier between him and the world.

    I’ll try attaching a second stand. I got one for myself but will happily give it up if it helps.

    I’ve emailed that company re. the attachment for the green holder Malvern. Thanks for your help.

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