Please school me in pop top lifters
Submitted: Tuesday, Jan 24, 2017 at 21:24
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Member - KeithB
I have never been in or used a pop top caravan before. But, for my sins, I am building one and am a bit confused about how much force will have to go into lifting the roof and pulling it down.
The combined weight of the roof, solar panels and canvas skirt will be about 90 kilos.I have purchased two scissor lifters for the ends which are claimed to give 30kg each. On top of that I am looking at two gas struts each side, each of which will give a vertical push of about 22 kilos when extended (88 for four) and 14 kg (56 total) when compressed.
So, on the face of it I will have net force pushing up. over and above the roof weight of 56 kg when it is extended. This means I will have to use most my body weight to pull it down.
Does this sound normal?
Keith
Reply By: Nomadic Navara - Wednesday, Jan 25, 2017 at 08:23
Wednesday, Jan 25, 2017 at 08:23
Keith, Are those gas strut forces are for the direct push or the actual vertical push taking the angles into account? I would think that when the top is down the gas struts would be giving zero lift as they are acting in the wrong direction to give a vertical lift.
Our van has
lifters similar to these inside. When the scissor lifts are due for service my wife can neither lift of drop the front of the pop-top.
I would suggest you do a little tyre kicking and
check things out for yourself on commercially made vans. Also wander into some repair
places and see if someone will talk to you.
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Follow Up By: Member - KeithB - Wednesday, Jan 25, 2017 at 10:10
Wednesday, Jan 25, 2017 at 10:10
Nomadic,
The forces I mentioned are resolved into the vertical.
Took a long time to dust of my 50 year old maths.
Keith
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