DIY Converting a manual penthouse to electric (A possible solution?)

[arctictraveller]

This is all very interesting. My GTRV top uses gas springs, I wonder if you could add a couple of them inboard of the springs. I had a hatch on my boat that was crazy heavy and hard to open, but with a couple gas springs it now opens with one finger. Just a thought.

[boywonder]

Originally Posted by Flakwagon

I got myself a spring scale. I measured about 170# to get it moving.

Including your weight?? If that's in addition to what you weigh that seems like way too much.....

[Flakwagon]

Originally Posted by boywonder

Including your weight?? If that's in addition to what you weigh that seems like way too much.....

170# in addition to my weight. Like I said this thing is heavy. But Once it gets going it's easy. I remeber it being pretty difficult to lift in the donor van as well. I'm pretty sure I put everything back together correctly. When I did the shoulder bolts through X of the lifting arms they moved pretty freely. The currently shuttle design is the only thing that has alot of friction.

[BUFFALO]

My top is very hard to lift also. I seem to remember when the van was new to us that it was much easier.
So you are shoulder pressing a 170lb top? I couldn't do that I'm pretty sure.
Is it possible something is binding? Can the springs weaken over time?
That just seems like way too much to expect someone to lift each time.
I see why you are so motivated to make this work.
I'm following with interest.

[Glider]

I have not had an easy time getting my top to move upward. After the first 12" it is fine, but the first 12" takes significant effort. For reasons I do not know, it was not that way at first, but it has become progressively more difficult over the past few months.

My solution: I pull out my gaucho about 6", then I lay the gaucho back on top of the seat for some added height. I then lie down on my back, and put my stocking feet against the PH top. It is a reasonable leg press to get it up the first 12". After that, I can stand up and guide the top's rise the rest of the way with minimal effort.

Interesting note: when the top is up, I hang all 115 lbs of myself from the handles to get it to start moving down. Once it starts moving, it comes down quite nicely.

Maybe this is mostly about friction. At the moment, I do not know.

[Nrobert10]

Mine does not have anything on top of it but I would guess it's less then 70# of pressure before it goes right up. For sure no way on mine it's 170#

[larrie]

I once put a bathroom scale under my cargo bar lift system. I remembering it being in the 70# range just before the springs took over.

[Tapatio]

I tried and failed with similar approach. Huge amounts of force needed.

http://www.sportsmobileforum.com/for...e-12529-3.html

[boywonder]

I'm struggling with 170lbs to lift the top, even with mis-adjusted springs....

I doubt that I can press a 170lb barbell........

70 lbs maybe......I'm visualizing pressing a 90lb bag of cement mix over my head...heavy...

I've been traveling for work for the last 3 weeks, otherwise I would have already put the bathroom scale in the van......

[Flakwagon]

Originally Posted by Tapatio

I tried and failed with similar approach. Huge amounts of force needed.

http://www.sportsmobileforum.com/for...e-12529-3.html

This thread is more helpful than I could have hoped. Thank you!

The approach someone in here used involved 2 actuators each pushing 150# vs 2 actuators each pushing 1100# I am proposing. With the angle of the bars closed the force applied to get the 276# assembly moving totals nearly 3200#

Someone in there has a link to a set of scissor lift equations and model.
Scissor Lift Jack Force Bottom Load Calculator | Engineers Edge | www.engineersedge.com

This is the model I am using to work this out. There is a set of free body diagrams in there as well if you dig far enough.

I havent given up on this but something seems very off with my top. 170# is alot of force require to get this thing moving. I checked again using a hi lift jack to take myself out of the equation. Pushed nearly 200# with my jack and blocks of wood weighing about 35#. so the 170# is about right

I did calculate my top to weight 276# which sounds about right based on how heavy it was to move around.

I do have strong reason to believe that friction is working strongly against me. I think the current design is binding. Even when I found the point of neutral buoyancy where the top would sit still, It would still take me nearly 60# of force to move the top in either direction.

The conclusion I am coming to is that with the 1100# actuators and the main springs all working together would give me a total of 3102# of force. the load calculator says I need 3162# of force to get it moving. Which means this idea would probably not work. Even with the top empty the numbers are too tight. Never mind the solar panels and cargobox I wish to add.

I am now leaning towards the use of a hi lift farm jack to get it up. It is a bit of a trick that I wanted to avoid, but I can at least do away with my bottle jack, and use this as a winch if needed.

All that being said, This topic is still open for discussion. Im still toying with other ideas for actuators and something that could be a simple push button solution.