I have a heavy king size bed in the caravan that needs to be lifted up to get under without breaking my back physically lifting it.
The head of the bed is against the front wall of the van so I have decided to use a couple of gas struts and run them from close to the centre of the bed and attach the other end at the foot end(or head end).
I used bathroom scales and a pyramid stand to weigh the centre of the bed where the strut will be attached and it weighed 50kg.
The 1st question is, as there will be 2 struts, what should I allow for for each individual strut? 25kg(245newtons) each or 50kg(490newtons) each? I think I'll be going for long struts, about 730mm long with the stroke being 330mm.
The second question is which direction should I put the struts? Like in figure 'A' or figure 'B'? And could you explain the reason for this please.
Also would I put the stroke part of the strut at the bottom and the thick part to the top or visa-versa? and again please explain why
Gas struts must be positioned so that the body of the strut is higher than the piston rod. This is so that the small amount of oil in the strut keeps the seals moist to prevent gas leakage.
You would need to do a vector diagram to workout the force required as the strut is not exerting all its force vertically, a fair proportion is actually pushing horizontally. the strength you would need is about 2 to 3 times higher than you have assumed
Alan
-- Edited by Brenda and Alan on Friday 31st of October 2014 12:29:26 PM
Jon further to my earlier post I have drawn a rough diagram to help you workout the required struts.
Alan
-- Edited by Brenda and Alan on Friday 31st of October 2014 05:03:19 PM
Thanks for the drawing and advise on which way up they should be mounted. I think a vector diagram may be a bit beyond me though and yes & yes for your 2 questions It had the king sized inner spring mattress plus bedding when weighed.
Cheers
Jon
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Home is where we hang our hats - Home now in Yamba NSW
Jon if you can work out the strut positioning to suit the strut length, lift the bed and prop it with a piece of wood the same length as the strut where it would be. Then just measure the angle of the piece of wood as shown on diagram with a kids protractor and estimate the strength needed from the table.
Jon, how far do you live from a caravan sales yard? Go along and do some tyre kicking. Whilst you are there you can examine dome of their beds and see the ratings of the gas struts and measure the installations. The strut pressure will change according to the dimensions of each installation.
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PeterD Nissan Navara D23 diesel auto, Spaceland pop-top Retired radio and electronics technician. NSW Central Coast.
Jon, how far do you live from a caravan sales yard? Go along and do some tyre kicking. Whilst you are there you can examine dome of their beds and see the ratings of the gas struts and measure the installations. The strut pressure will change according to the dimensions of each installation.
Thanks for the idea Peter but I think our bed is quite a bit heavier than the standard caravan bed so might not be much help.
I tracked down a hydraulics place here in Grafton and they advised me that when I buy struts from them they can put whatever gas pressure I want into them and if I find it is too low or high I can bring them back and they can increase or decrease the pressure to whatever is needed, so that solves that problem. I also told the guy about what I wanted it for and he suggested I start with 40kg each.
Cheers
Jon
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Home is where we hang our hats - Home now in Yamba NSW
Jon if you can work out the strut positioning to suit the strut length, lift the bed and prop it with a piece of wood the same length as the strut where it would be. Then just measure the angle of the piece of wood as shown on diagram with a kids protractor and estimate the strength needed from the table.
Alan
On the other hand you could just use the piece of wood rather than the strut.
Sorry .. just couldn't help myself ....... Just joking!!!
Thanks for the suggestion Brenda & Alan, I'll look into it.
As for you're idea Cupie...I have been propping it up with a piece of wood for 2 years but, unluckily, it has to be lifted before it can be proped up and wood just won't do that by itself no matter how much coaxing I give it
-- Edited by Hylda&Jon on Saturday 1st of November 2014 09:49:01 PM
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Home is where we hang our hats - Home now in Yamba NSW
