Has anyone ever used hydraulic door closers for pop-top or bed lift?

[KeyserSoSay]

So they are remodeling my office a bit and I found one of those hydraulic door closers sitting in the coffee room. I started fiddling with it and realized there is a lot of maintenance-free stored energy in a small and easily/sturdily attached package. The one I have here has two 3/8" square drive attachments meaning you could easily build and attach whatever type of swing arm you want and they could be damn sturdy, and the return weight and speed are adjustable. I did a little googleing and found that these are not that expensive and you can easily pick up 4 of them for $100 to $160 depending on what weight rating you go with. the weight ratings are not true ratings as I believe they're based on the weight of the door they could close, but I'm confident 4 of these could lift a piece of plywood and a mattress and hold it up and out of your way, to be pulled down and used at your discretion.
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I tried to search the ExPo site a bit without luck, was interested if anyone had attempted this or anything similar. made up a picture below to show where my mind went with it, interested in where other's minds may take it or have taken it.....

 

[Coachgeo]

Folk may not be responding cause they don't understand it yet. Im totaly baffled but intrigued. Subscribed!!!

 

[kmlacroix]

Gas struts will be lighter and stronger.

 

[KeyserSoSay]

Ha, thanks, I kinda did feel a little like the nerdy kid standing all by myself at the back of the dance after posting this with such excitement.
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Effectively, these are the same as the closed-system hydraulic (gas) struts we use to lift car hoods or back hatches, and RVers have found many other uses for them, except these door closers utilize a twisting motion instead of a linear ram. What comes to my mind is that hydraulic struts, and other linear actuators are often used with some mechanical frame or scissor lift type of mechanisms, where these twisting arm mechanisms might be used in some situations for a much more simple machine, with fewer pinch points, and more stored energy per cubic inch of apparatus. These have been engineered to be a clean little box smaller than a fruit cake, that are aesthetically pleasing to see if you even notice them at all.
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I've studied enough of the DIY pop-tops to understand the principals of building a lifting system using a (12v) linear actuator allowing you to lift and lower your pop top with the push of a button. While I had intended to use 12v motor driven actuators in my pop-top design (because I can and why not do it RIGHT) , I'm beginning to understand that it's possible to build these too fancy for your own good. If I could build a pop-top that had a strong and positive latching mechanism, didn't leak or rattle, lifted up on it's own due to stored hydraulic energy, and was a simple easy effort to just pull down and latch closed, that might be the smarter route to go. I think these door closers make that a possibility.
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Right now I'm currently leaning towards just having a fixed high top on my bus, and not bothering with a tented pop-top. My little school bus has all the room I need for comfortable camping, but it's a few inches too short to stand up in for me at 5'9". My plan is to prototype a bed lift (like I diagrammed in the posted picture) that stores a double bed overhead and allows me to stand comfortably underneath it. I'm confident I can do this with a clean, eloquently designed, lifting system using these door closer hydraulic lifts. If/when I pull it off I'll post it here in this thread for others to think on when they approach this chore. But who knows, I'm still early in my planning of the interior for my camper van build.
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I will say this, gas struts are lighter and stronger per cubic inch (as I've just now seen noted here) , but have ZERO strength in any other plane than the in-out, and subsequently require a heavy frame or apparatus to be built around it in order to make use of that linear strength without being wobbly or hinky. I disagree on the weight/strength in that context, which is why I've brought this up here. Gas struts will still be better for many chores, but there are some projects where these twist lifters would be a better choice.

 

[Coachgeo]

Just a side note..... back in the old German Military Unimog Command boxes (404's) they could not stand in the box either... heck they were bairly 5foot tall boxes.... BUT........ they never needed too. They rolled around on wheeled chairs. Build the inside of the camping space same way one builds a house for a wheelchair bound person. Just a thought.

Still like this hydraulic idea though has potential for Murphy bed tool

 

[Mwilliamshs]

The hydraulic part of a doorcloser is what allows the slow, quiet closing. It resists the energy which actually does the closing. The hydraulic part is like a shock absorber, counteracting a big, strong spring. The adjustability is just like an adjustable shock (Rancho 9000, etc). You can adjust the size of the orifice through which fluid passes (typically a needle valve). There's no "stored hydraulic energy." The stored energy is just a spring that's wound or compressed, being balanced against a hydraulic damper to control its unwinding or extension. The leverage ratios of closers make them difficult to repurprose because they have limited ranges of motion to start with, and their dampers are position-sensitive.

 

[KeyserSoSay]

Alright. I've got no argument against anything you say and I don't mean to be Don Quixote jousting windmills over these things. The closer I've got has about 66 degrees of rotational range, is stout enough to handle solid/ heavy steel swing arm without any wiggleing or wobbleing, and plenty of stored energy (be it a spring or hydraulic or whatever) that 4 of them could easily lift a mattress and a sheet of plywood. I really concider this a lift assist as I just mean for it to allow me to lift and lower the bed with one hand- there are a wide range of these closers and the trick is to find the model that will (x4) most closely match the weight of my bed. The key to using these as a bed or pop-top lift will be a well designed latching system that will lock them in the up and down position easily and without wiggle-wobble. Time will tell if I've over-estimated the utility of these for this task, but I'll post the outcome here whether it's a fail or a win.

 

[Mwilliamshs]

You need a positive rest for the bed when down. Don't expect the closers to support the weight. You'll also need a positive stop for it when up to maintain preload on the closer. I would also want the bed positively secured when up so it couldn't fall down or bounce against its stops.

 

[Mwilliamshs]

How far does the bed need to move vertically? In other words, what's the height difference between bed up and bed down?

 

[Eaglefreek]

I used to install commercial doors and have installed many door closers. I don't they will do what you want then to do. Think about the minimal force required to open a door that has a closer installed on it. Maybe if you made sure you got closers with a backcheck adjustment, it might sort of work. But gas struts would work better in my opinion.

 

[KeyserSoSay]

:smilies27

I used to install commercial doors and have installed many door closers. I don't they will do what you want then to do. Think about the minimal force required to open a door that has a closer installed on it. Maybe if you made sure you got closers with a backcheck adjustment, it might sort of work. But gas struts would work better in my opinion.

Thanks, that's the obvious consensus here so I'll just have to temper my hard-headedness against the prevailing wisdom. Full disclosure: I'm not quite ready yet to seek treatment for my door-closer crack addiction so I'm probably going to have to actually fail at it before I fully concede to the intervention- but I do appreciate everyone's input and attempt to save me from myself.:smilies27. I'm man enough to post up my failure here to help others, but that will be several months out regardless.

 

[45Kevin]

The closers do store a fair amount of energy. It is gained when you open the door. You don't feel it so much because because you open the door by pushing about 3 feet from the hinge while the closer is mounted at less that a foot from the hinge.
You may be able to use the closers to help lift the roof, by getting the energy from pulling the roof down.
Sounds like too many moving parts to coordinate to me though.
But don't give up just because a few guys that have never tried it say it can't be done.

 

[philos]

As long as you mention the magic phrase* before you do it, I ain't stopping you...





*"...hold my beer."


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[Mwilliamshs]

For the record, I just clarified the workings, enumerated some of the complications I see, gave some advice, and asked a question or two. Never said it couldn't be done or that wouldn't work or that there wasn't energy stored in the closer.

 

[KeyserSoSay]

No worries at all, I appreciate everyone who took the time and effort to post on this thread that I started specifically seeking insight and wisdom on these potential lifters and I don't intend to discredit or dismiss any of that wisdom.

I've got a solid simple design plan that I think is going to work awesome and that others may ultimately find useful. I'm going to give it a shot (eventually) and post it up here to put the issue to rest for better or for worse.