Request for help with a hoist project
The Essex South (formerly Southend) panel have asked for ideas on making a hoist for Steve, who has muscular dystrophy. Steve himself has thought considerably about his problem, and this is the request he put to the panel.
If you have any thoughts, please use the comments box at the end of this post. The first time you use it it may be several hours before your contribution appears.
This is Steve’s description of his problem and requirement:-
My name is Steve . I have had muscular dystrophy all my life. I am now fifty years old, and my MD is fairly advanced – I am for all intents and purposes, virtually quadriplegic. I weigh approximately seventy five kilograms. I cannot support my own weight, so all transfers require me to use hoists.
About my current kit …
I use a powered wheelchair, a privately purchased "Otto Bock B400" (with optional luggage rack and headrest). I have hoists installed at home, in both bathroom and bedroom, which I have to use for all transfers (mostly using an upper body sling, leaving my legs free).
What I need …
I need a portable hoist that I can use when I am away from home. At the moment the only toilet I can use in the entire world, is the one in my own home, as that is the only one with a hoist – this is definitely a major impediment to my freedom!
What I want …
I want a portable hoist that is convenient to carry, deploy, and use, wherever I may be. In particular
I want one that is attached to, and stowed (when not in use) on my wheelchair.
Design Ideas … (incomplete ramblings)
The most basic minimalist hoist structure could comprise a transfer beam with an "A" frame supporting each end.
This would obviously be unstable and would need bracing. However, if one end of the transfer beam is instead supported by a rigid upright, firmly secured to my wheelchair, then this could provide sufficient stability, and only a simple "A" frame would be needed at the other end.
The next problem is the transfer beam itself; this would have to be heavy to have sufficient strength not to bend in the middle. It also needs to be approximately a meter and a half in length, but still be dismantle-able for stowage (separable or foldable into short sections).
I wonder if we could replace the transfer beam with a cable looping around two pulleys, one at each end of a simple (but much lighter) compression beam?
I’d suggest using a double tackle pulley system for actual hoist/lifting (giving 4 to 1 lift/pull ratio). We need to design a minimalist sling/belt for secure upper body fitment during lifting. We also need to work out some way to lock the lift line during the traverse from "seat to seat", and also a system to operate the traverse.
If I was making this myself, I’d hope to make most of it using short light sections of aluminium (or possibly even plastic) tubing, wrapped in carbon fibre, with short sections of steel rod (or possibly tube filled with carbon fibre) as inserts at tube joints. This should give ample compression strength for the "A" frame and compression beam, and might possibly also suffice for the rigid upright.
We asked Steve to tell us a little more about the kind of circumstances in which he envisaged using the hoist. Clearly space would be critical. This was his answer:
Basically I want something very very minimalist. All of the "portable" transfer hoists on the market, are stand-alone – so they would normally require enough space to straddle both toilet AND wheelchair. I’d like something designed as a wheelchair attachment, which would immediately just for that, take up less space. I also use the word "portable" somewhat loosely, as all that I’ve seen on the market are hardly what any regular person would call conveniently portable.
Spacewise, I’m hoping to aim at relatively spacious bathrooms. Specifically, if there’s enough room to get a powered wheelchair in, with space for a helper to transfer, then it ought to be possible to have a hoist rig that could fit and be helpful. My parent’s bathroom is relatively tight but there is space to park a chariot near the toilet, and still allow a helper to manoeuvre. My brother’s bathroom is very spacious. Ideally I’d like to be able to use public disabled toilets too – most of these have space to allow a chariot to be parked near the toilet.
I need the thing to be relatively simple to assemble, and hopefully stowable in little more than a tent-pole bag. I don’t want something that has to be a permanent encumbrance on my wheelchair either – portable is wanted so it can be left at home when not needed. I envisage, that with anchor points mounted on the back of my powered wheelchair, a lot of the required safety stability should come from the weight of the chair itself – allowing a relatively light and maybe even flimsy hoist frame – provided it’s stiff enough, it should be stable enough.
I realise this idea needs more thought – and that if remap can help – it might still be a longshot, but I do know from past experience that you have some very very ingenious people contributing their engineering minds. I’ve only the beginnings of ideas so far, still need to sort much out, (not least, the actual manual lift and traverse mechanism and also minimalist sling arrangement) but … If anybody can, Remap can.
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