Please school me in pop top lifters

Submitted: Tuesday, Jan 24, 2017 at 21:24
ThreadID: 134183 Views:3108 Replies:8 FollowUps:6
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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


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Reply By: Member - John T (Tamworth NSW) - Wednesday, Jan 25, 2017 at 07:48

Wednesday, Jan 25, 2017 at 07:48
Good morning Keith
Can't help re forces mate but can tell you that my AOR Quantum has scissor lifts sides and ends and requires very little effort to "pop" and "unpop". These are 2 solar panels on the roof but again I have no idea what the total weight of the roof might be. A call to AOR at Caloundra might answer your questions.
Good luck with the build

Cheers

John
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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.
PeterD
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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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Reply By: swampy - Wednesday, Jan 25, 2017 at 08:40

Wednesday, Jan 25, 2017 at 08:40
hi
Find the closest poptop to your requirements and either copy it or do a complete transplant of a known unit that works .Angles/ mountings and specifications of the gas struts are critical for good lift operation .
It also makes it easy for spares if they are of the shelf items and not custom fabricated .
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Reply By: AlanTH - Wednesday, Jan 25, 2017 at 10:28

Wednesday, Jan 25, 2017 at 10:28
When it's all finished and looking good, don't forget to open the door when lifting/lowering the roof. I told a young couple some years back about this as they were having a terrible time trying to do it without the open door for air to go out or come in.
AlanH.
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Follow Up By: Member - David M (SA) - Wednesday, Jan 25, 2017 at 15:10

Wednesday, Jan 25, 2017 at 15:10
Now you tell me ! :)
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Reply By: Member - nick b - Wednesday, Jan 25, 2017 at 11:17

Wednesday, Jan 25, 2017 at 11:17
Kieth : when ordering gas strut from a reputable supplier / manufacturer
you give then a drawings weights of the job & they will supply the right struts for the job ...... we hope .
Cheers Nick b
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Reply By: Malcom M - Wednesday, Jan 25, 2017 at 11:25

Wednesday, Jan 25, 2017 at 11:25
Suggest you join myswag.org.
Free forum dedicated to trailer based camping stuff. Plenty of people building pop tops with struts or linear actuators.
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Reply By: Member - KeithB - Wednesday, Jan 25, 2017 at 11:39

Wednesday, Jan 25, 2017 at 11:39
Thanks everyone. I think the Quantum set up with four scissor lifts might be best.
I'll be off the air till tomorrow night but will welcome any more replies.
Keith
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Follow Up By: Shaker - Wednesday, Jan 25, 2017 at 13:39

Wednesday, Jan 25, 2017 at 13:39
The Quantum roof goes up in one lift, others like the Coromal go up one end then the other.

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Follow Up By: Nomadic Navara - Wednesday, Jan 25, 2017 at 15:06

Wednesday, Jan 25, 2017 at 15:06
"The Quantum roof goes up in one lift,"
Is that because the lifting and lowering is done by handles under the ceiling like we had in our Nipper? Our next two vans had scissor lifts along the sides, the Regent had one each side and the Spaceland had two. Both of those could have one end or the other raised or lowered without doing the other end at the same time. The Spaceland with the longer pop-top had Easy Lifters but the Regent did not (nor did the Nipper.)
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Follow Up By: Member - John T (Tamworth NSW) - Wednesday, Jan 25, 2017 at 15:23

Wednesday, Jan 25, 2017 at 15:23
Hi Peter
Yes mate, the Quantum has the lift handles under the ceiling so the whole roof goes up at once.

Cheers

John
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Reply By: RMD - Wednesday, Jan 25, 2017 at 21:54

Wednesday, Jan 25, 2017 at 21:54
Did you work out the VECTOR forces for all devices? Did you use the actual angles or the full push amount?
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Follow Up By: Member - KeithB - Thursday, Jan 26, 2017 at 18:58

Thursday, Jan 26, 2017 at 18:58
I used the vector fprces
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