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Request for help with a hoist project

  • Ian D Midgley
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  • 6 comments

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.

 

 

Photos of Steve’s wheelchairSKMBT sml 005

 

SKMBT sml 003

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6 responses to “Request for help with a hoist project”

  1. John Mack says:

    Congratulations on a super site for brainstorming! That’s just what lone designers need. But surely we can post sketches – since photos have been. In the last resort, please (Susan, Peter?), where’s the Instructions? (I’m new here.)

    How far has this project got? Is it still appropriate to brainstorm?

    Steve seems to know what he is about. I wish I was local, I’d like to talk to him. Is there some way to get him on here? Or can I have his email?

    From Steve’s mention of a 2-pulley sheave, it sounds as though he is considering manual lift and transfer. Is he seeking to be independent of a carer?

    Could Steve use the toilet facing round the wrong way? (I find that on one of mine I can, easily, but I had to take off one trouser leg to get right on.) Then the hoist would carry him straight forwards (it need not be exactly in line with the bowl), which should enhance stability during transfer. The beam might be shorter, too.

    Attaching the hoist to the chair sounds good for any transfer thrust, although perhaps the supports should also rest widely on the floor for tilt stability.

    This hoist must pack-up small – like a hiker’s tent poles. For quick erection and packing, folding joints sound preferable to connections. Such operational convenience might favour any additional design time.

    Steve’s suggestion of two pulleys and a cable loop for transfer is fascinating. It sounds light and small, but I’d have to make a model to assess any tendency to run down to the mid point.

    Carbon fibre tubes are immensely strong and light. However, they should be woven to prevent the fibres splitting apart (or be bound). Fishing pole makers could supply tapered tubes – which plug together, conveniently. Perhaps, for easy separation, a collar could be epoxied to the inner member to limit its engagement. Retention would be needed only if there is a risk of tension. However, folding would probably be more convenient in use. The 3-tube joint at the top of the legs would probably involve turned plugs epoxied in, with lugs for folding.

    See http://www.dlf.org.uk/factsheets/Choosing_a_mobile_hoist_sponsored_0.pdf , eg, for useful discussion points.

    Would Steve give more guidance on the body belt and balance? Can he stabilize himself with his legs at all?

    Joanna, you’re right to highlight the safety requirements for lifting equipment – both for Steve’s sake and to cover Remap’s back. Perhaps you would suggest a Testing or Approval Authority for one-off builds. However, I feel that your negativity is misplaced and stifling of innovation. When Steve says “flimsy” he doesn’t mean (I think) something that will buckle in use – or even under inadvertent misuse. Designers are used to this sort of problem and would include overload testing as a matter of course during development. I infer, from his provision, that Steve knows this well. I imagine he has something much lighter than a Molift in mind. “Minimalist” need not mean fragile, although it does mean sound design. Think Space Engineering or Microlights.

    Commercial hoists look massive and heavy, mostly because they are powered and because they use tubes in bending. Steve’s proposals are essentially lighter, using a space frame in compression. Buckling would then be the problem, which is catastrophic compared with bending, so we’d use large-enough diameter thin-walled tubes. I’d like to develop his ideas further if he’s still interested.

    But I’m new. Is that how we work?

  2. Mike Bennett says:

    Not being able to put scanned drawings into this type of email makes this difficult to convey this idea so words will have to suffuce.
    I agree with the others about hoists and the difficulty/risks that they present. So I’m suggesting that he be slid onto a second wheeled seat designed as follows:
    1. The base for this seat should be wheeled (swivel type) on a “C” frame (such as on an engine hoist) designed to go either side of the wheelchair.
    2. Mounted on this wheeled base should be a hydraulic car jack to enable the height of the seat to be varied as required.
    3. In this case it is suggested that the seat be designed as a toilet seat (i.e. a supported board/plastic with an appropriate sized hole) cantilevered over the “C” frame base.
    4. A suitable support for the client would be required. This it is envisaged would be curved and mounted on a central support so that the client’s legs can pass either side of this support. The client would therefore be sitting as if on a seat the wrong way round and resting on the chair back Christine Keeler style.

    With the seat height adjusted to the same as the wheelchair the wheeled toilet seat would be wheeled up to the client and positioned between his legs and as far under his bottom as possible. He would then be slid onto the toilet seat and over the hole, with the curved support against his chest or wherever he is best supported. PTFE on the seat would probably make the sliding transfer easier though other plastics (cheaper?) could be considered. A method of latching the seat to the wheelchair might make the transfer more secure.

    The client is then wheeled and positioned over the toilet and the height of the seat adjusted to suit the toilet height.

    To return the client to his wheelchair the reverse procedure would be followed.

    To make the wheeled seat portable some consideration would have to be given to make it so it can be dismantled.

  3. Joanna Clark says:

    In reply to the enquiry about a hoist for the gentleman with MD, I feel that such a slimline portable device would be inadequate for it’s purpose.
    Bearing in mind the British Standards to be complied with on commercially available hoists (and slings) and the stringent tests they have to go through it is a high risk area. In the early days there were 2 band slings which fitted easily behind the back and under the thighs but these were replaced by one piece slings due to the number of accidents of people falling through them. Transporting or attaching a hoist that is strong enough to lift someone of 75kg on the wheelchair is going to affect the stability of the chair. Regular maintenance of weight bearing equipment is also very important.
    Sorry to sound negative, while I can appreciate Steve’s desire to visit family my main concern is his safety coupled with the extent of Remap’s responsibility. If space permitted in any of his family’s bathrooms it may be possible to hire a small portable hoist e.g. the Molift which folds down very compactly although I do not have personal experience of it so cannot recommend it. However they can be hired and delivered (including to hotels). I don’t know whether this type of hoist would be suitable for Steve’s condition but discussion with him and his OT / Physio / MD nurse advisor or Remap panel OT would be advisable.
    Information on small portable hoists can be found on the Disabled Living Foundation website and some can be seen there or in Disabled Living Centres around the country by appt. Suppliers also sometimes have showrooms or will do demonstrations.
    Hope this is helpful.
    Joanna
    OT

  4. Alan Hart says:

    II have already posted here but with the wrong problem(You just cant get the staff these days) so here is my view on this request
    No pictures and drawings are available in this format but let me know if you want to see them and I will send a copy of the e-mail if you need it. (Perhaps this format should include sending a document attachment?)
    Start here……..

    I contact a paraplegic in the States that I correspond with, asking your question, sending your original e-mail and my response. Remembering he types with a stick in his mouth he sent this to me. Excuse the end of his letter which I have amended is directly below..
    .
    the hoist design borrows elements from a hoyer lift. the confinement of a restroom stall, even a disabled-capable stall, makes it very difficult problem. I agree fully with all your points, especially regarding carbon-fiber structure. i cannot conceive anything useful and easily portable that could hoist and place a substantial man on a public toilet before he does it in his pants.
    j.

    —– Original Message —–
    From: Alan Hart
    To: Sent: Wednesday, February 29, 2012 8:38 AM

    Hello Paul,

    I read about Steve from Remaps round Robin and I have always given these some thought. On this occasion I decided it was too difficult and went onto the next e-mail I am sure you know how it is. But I come back to it and writing this on the fly so to speak as thoughts occur so forgive me if it rambles a bit

    The first is its going to be very difficult.

    1. You are carrying around a hoist which may only be used in ‘suitable’ rest rooms.

    2. Whatever you use it will have to be strong and that means strong material.

    3. Lifting sideways a mass of 75kgor nearly 12 stone (in Christian units) is going to need a sizeable frame that operates -left to right’ -which means a wide stand.
    It must also be able to operate either side of the toilet as the space may be on the left or right in the rest room or even no space either side in which case it will have to operate in the forward position.

    4. The stand will have to be attached to the chair or some form of mobile constructed stand as it will have to be very stable.

    5. Using carbon fibre is fine if you can find carbon fibre tubing. Carbon fibre needs heat and pressure to form and it’s not like fixing the dent in your car, or making a mould.
    Although carbon fibre is strong I would not trust to be strong enough to move 12 stone 30 “ (C.Unit) away from the base plate. It may look good and strong on racing cars but a slight knock and it breaks. It’s a very specialised industry and a very specialised exercise in stress.

    6. Then there is applying movement. I am assuming your not using a block and tackle and you will feed a motor with a handset on a roving lead.

    7. Feeding a motor means you will have to source power either from the chair or a separate battery.

    8. You can not assume all toilet configurations will be the same so you may not be able to get the chair into a position that the swing carries Steve over the require spot.
    9 Its going to be very heavy and you will need at least one spanner.

    Generally pretty negative thoughts.

    Can we turn it into positives? Taking each above in turn

    1. ‘Most’ handicapped rooms have enough room for wheelchair access but not always side access so the frame will have to be able to swing in a multi directional way. Bit like a bull’s eye but sitting on the outer circle trying to get swing onto bulls eye. I still see difficulties in this.

    2. Whatever you use will have to be strong. If you’re using aluminium it will have to be thick walled to support 12 stone. Carbon fibre is out unless you know someone who can manufacture the structure (whatever that turn out to be) under pressure and heat. Wood seems the most suitable as it is strong and easily shaped for most configurations with attachments easily connected to the structure. Anything else requires welding or fibre glassing. I think a wooden structure most suitable but the whole frame may be quite heavy.

    3. Depending on the mass of the chair depends how far you can swing Steve away from the chair without it toppling. To stop topple you will need to put out further ‘feet’ either in terms of floor ‘feet’ laid lengthwise and attached to the chair or by some other means such as an overhead support with long legs like a gazebo leg support.

    4 Some form of support could be attached to the two uprights at the back of the chair. They would have to be substantial as any deforming would affect the chair structure. If it’s not attached to the chair, which does limit design, then perhaps the simple A frame engine hoist configuration would be suitable. It can be easily folded, has greater mobility, it can be electrically controlled for hoisting and with wheels and brakes quite manoeuvrable but still very heavy.

    5 See 2 above

    6 Block and tackle is OK if your on board ship with fixed ropes but they are will be a difficult thing to control if you pack them away because sure as eggs are eggs they will get tangled up.

    7 A simpler solution is a starter motor from a car with a 12v battery. A hand held control can give movement up and down by reversing the polarity of the wiring. You will need to make some form of polarity box to change the motor direction. Attachment can be permanent to the chair rather than a take away part.
    For a short duration of use you may be able to simply fit a plug to the existing wiring as an outlet for power and simply plug in the starter (assuming it’s a 12v battery). If its 24V you will have to get a regulator of sorts to reduce the voltage to 12v.

    8 My initial thought was a gantry where you simply moved sideways with the frame with the gazebo legs giving support.
    However the toilet design may not allow you to get close enough to the side.
    This brings me back to a separate unit like the A frame engine hoist.

    9 Assuming you decide on the A frame the assembly is pretty basic and the weight manageable. However the metal ones used in garages have a hydraulic lift mechanism which would greatly assist you. I fear that the fold away in a tent bag is optimistic as whatever you choose to use will have to be substantial.

    10 There is of course the Mk 1 thought of a simple slide board if you can remove one of the chair arm sides, But Steve needs slings to move him.
    I suppose you could insert a slide into the chair like a kitchen drawer that with supports, could be slid sideways using light framework within the existing chair.

    11 The unit comprises an all encompassing upper body support for Steve giving support to side and back.
    A fibre glass seat moulded to his body with long wing side so he sits in it and has side support could be used as the transfer chair.
    It would sit within the existing chair with some form of moulded cushion to cover the hole and provide seat support for Steve.
    A lap strap and upper body strap would confine him when moving onto the slide board and toilet.

    12 A sliding ‘holed’ seat under him that slides over the toilet with leg supports at the end. This could be folded or flat but it will be another item to carry. You have now gone to from the small tent bag to the kit bag for stowage of these movable items

    It can be motor driven for the third hand.

    You seem to have a very difficult task on your hands and I am sorry to be so negative although I hope you can pick one thing out of my thoughts that may help you. I am making enquires elsewhere about this problem and may follow it up with some more thoughts.

    I have already mailed Paul but the biggest problem is Steve’s mass. The frame that will support that supports that mass and moves him from A to B will have to be substantial. It is really a very difficult situation and whatever you do,
    If portable, it will be very heavy not to mention the size of the thing. Attaching it to the wheelchair and using it as a base is not recommended as it will become very unstable as the mass is moved away from the chair

    Alan Hart
    IOW Panel chairman

  5. PeterP says:

    I wonder if a better approach would be to build a tepee (3 leg/shear leg) hoist
    such as shown at
    <http://www.angliahandling.co.uk/acatalog/Aluminium_Tripod.html>
    or
    <http://www.liftingsafety.co.uk/product/advanced-tripods-from-sala-ucl
    -3525.html>
    (The first link shows a simple adjustable tripod weighing only
    14.3kg.)

    and use this in conjunction with a very minimalist folding chair.

    The tripod would probably have to be nearly the height of the room
    but as everything is in compression you wouldn’t need fancy materials
    – normal aluminium poles either round or rectangular with slip in
    jointing pieces would do. That should make the construction
    relatively simple and the device easy to break down into manageable
    bits. As it wouldn’t need to be adjustable in height that simplifies
    things as well. The feet can be simple as a floor level base rope
    can be used to stabilise the three feet.

    Having hoisted Steve up, rather than trying to move him sideways –
    which is where all the problems of bracing and stability start, make
    a collapsible version of a commode chair such as at :-

    <http://www.dayshealthcare.co.uk/products/1/bathing-aids/56/commodes/7
    015/folding-commode-chair-and-toilet-surround.aspx>

    but fit it with suitable wheels

    He could be hoisted out of his wheelchair, the wheel-chair backed out
    from under him, the commode chair pushed in (using a toilet seat top
    rather than a commode) and Steve lowered onto that seat. That could
    be done in any nearby room – it wouldn’t have to fit into the
    bathroom.

    The seat could then be wheeled over a normal toilet needing very
    little space either side (the chair has no low level back cross
    brace).

    The combination of hoist and seat (folded flat) should fit at the
    back of his wheel-chair (albeit it will be a bulky load) and would
    require no special skill to erect and use.

    <http://www.liftingsafety.co.uk/product/aluminium-tripod-gantry-crane-
    man-riding-140kg-materials-lifting-1000kg-3992.html> has some useful
    pictures.

  6. Sue Dunn says:

    The “big Body squad” programme on Channel 5 29th Feb.showed the fire service using a large 3 pole system with pulley. A smaller, folding version of this might be what this client is thinking of.
    However few people can be lifted safely just using the upper body sling particularly if they have a condition causing general body weakness

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