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Go Back   IceInSpace > Equipment > DIY Observatories

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  #1  
Old 24-06-2017, 04:53 PM
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el_draco (Rom)
Politically incorrect.

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Roll off Roof question...

Building a R.O.R. a.t.m. and put the first of the rollers together today. That went well enough but has introduced a potential issue.

The roof itself will weigh in at about 250kg when done and I don't fancy trying to stop it if it builds up any velocity.... and really don't want to chase it down the side of the mountain where I am building.

It'll be automated at some point but does anyone have a basic breaking system design that I can use to start with. Don't really want to look at hanging weights, (for the obvious reason), if I can avoid it....

Rom
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  #2  
Old 24-06-2017, 05:53 PM
glend (Glen)
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Garage door springs. How are you going to get the roof onto the track? I built a ramp and ran my roof up the ramp till it could run into the track. It can be a pretty dangerous task to get the roof on, scared the heck out of me.
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  #3  
Old 24-06-2017, 06:57 PM
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el_draco (Rom)
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Originally Posted by glend View Post
Garage door springs. How are you going to get the roof onto the track? I built a ramp and ran my roof up the ramp till it could run into the track. It can be a pretty dangerous task to get the roof on, scared the heck out of me.
What you did sounds a hell of a lot scarier than what I had in mind.
My track is 2.5 m above the ground at its lowest point and the roof is about 20sqm; a bit big to get heroic, I suspect. I am building the ROR under my house a.t.m. and will then disassemble and reassemble it in situ using a couple of my ape-men sons and a mug I know, if I can prise him out of his dome.

Weather is the enemy atm. Snowed up there last night and I am currently locked out... alas, will only get worse!

Garage door springs... like shockers? May be a useful idea and I'll look into that.
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  #4  
Old 24-06-2017, 07:22 PM
rally
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Rom,

How about some rubber or polyurethane blocks in the right spots.

If it weighs a few hundred kgs then it will have a lot of energy if you slam it too fast
So rather than break something it will compress the rubber gently and then return in the other direction.

If you put a rack and pinion on it now - it might be a bit slower to close but it would be hard to get up too much speed
Then when you get your automation sorted out - its ready to go

Last edited by rally; 24-06-2017 at 07:47 PM.
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  #5  
Old 24-06-2017, 07:55 PM
glend (Glen)
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I was suggesting the type of garage door springs used on panel lift doors, they are there to assist with initial movement when compressed but stop travel progressively on extension.
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  #6  
Old 25-06-2017, 04:17 PM
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el_draco (Rom)
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Originally Posted by rally View Post
Rom,

How about some rubber or polyurethane blocks in the right spots.

If it weighs a few hundred kgs then it will have a lot of energy if you slam it too fast
So rather than break something it will compress the rubber gently and then return in the other direction.

If you put a rack and pinion on it now - it might be a bit slower to close but it would be hard to get up too much speed
Then when you get your automation sorted out - its ready to go
I reckon it would pulverise the polyurethane because it looks like this thing is going to move very easily but it may be worth looking at a rack and pinion set up, perhaps with some garage door springs similar to what Glen has suggested. Bugger, it's big.

Automation will be a goal but I plan to live within about 150m of the obs in the not to distant future... touch wood. Sure be nice not having to trudge through snow to open and close the thing. More research required me thinks

Last edited by el_draco; 25-06-2017 at 05:49 PM.
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  #7  
Old 26-06-2017, 02:36 PM
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jenchris (Jennifer)
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A car steering damper will allow the roof to be slowed during the last couple of feet if you set it up right.
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  #8  
Old 27-06-2017, 10:55 AM
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Somnium (Aidan)
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Just bite the bullet and automate it. it isn't that expensive to get an electric gate opener from ebay and set it up, you wont regret it
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  #9  
Old 29-06-2017, 06:17 PM
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el_draco (Rom)
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Just bite the bullet and automate it. it isn't that expensive to get an electric gate opener from ebay and set it up, you wont regret it
Hmmm... I've been looking. Are there any stand out systems about for this application?
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  #10  
Old 12-07-2017, 11:43 AM
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stefang (Stefan)
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Roll Off

Having just gone through the automation of a ROR process myself, here are some considerations to think of when the time comes to motorise your ROR

Ultimately you need to consider the following:
  1. What is the weight of the roof assembly?
  2. Do you require a solution for a single or split roof configuration?
  3. Do you need 24V or 12v etc
  4. Are you planning on using limit switches (magnetic, actuators etc)?
  5. Are you on grid or off grid power?
  6. Are you installing solar panels on the roof of the obs?

We initially installed a couple of Gate Opener units from Grays as below. We have a 1200kg unit on our south roof, and a 800kg rated unit on the Northern roof assembly. As we have 4 x 350kw solar panels on our southern roof, we needed something with some more torque to move the roof that drives a 6kw off grid power bank.

Gate Opener - Graysonline

About $399 including track

However, after a month or so of experimentation we swapped out the units for dedicated (60RPM) 12v motors. More torque, far lower power consumption, fully weatherproof and sealed geared motors with a keyed shaft.

120 Watt Geared motors. We sent the gearing from the gate opener unit off to a fabricator to have new gears machined from Brass so they are self lubricating.

About $119 for the motor+ $158 for the gearbox and mounting flange. New brass gears machined from stock were are about $190 bucks each

Ultimately budget, power source & reliability will be your key considerations.

If you are off grid keep in mind that the coils on a gate opener pull excessive power at start up. As our Obs is off grid we went with the smaller geared precision motors as they only pull 110watts, vs 500-600watts the coils alone draw when you activate the gate opener option. If you are off grid opening and closing the roof a handful of times can bleed your power store dry.

good luck
Stefan

Last edited by stefang; 12-07-2017 at 12:34 PM.
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  #11  
Old 17-07-2017, 11:02 AM
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The_bluester (Paul)
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I am still quietly dreaming on for my own build. One thing that occurred to me if the roof was either automated or just electrically driven (With a little more design work it could work for a handle to twirl as well)

A rack and pinion is one thing however better again if one could be found would be a rack and worm gear. Reason being the worm gear (powered either by an electric motor or handle) will drive the rack however the rack can not drive the worm gear, so once moved to a position the wind will not be able to move the roof.
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  #12  
Old 17-07-2017, 01:27 PM
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el_draco (Rom)
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Hi Stefan. thankfully, I am on grid so that should help the situation considerably. Miracle I got the power to the site; really decent neighbour to thank for that. I am building the roof atm. It rolls on 6 pallet jack rollers and, the framework at least, moves very easily. I also lucked out by building high walls so the "park" issue, wont be. Definitely going for the gearing straight up so your advice is much appreciated .
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  #13  
Old 17-07-2017, 02:33 PM
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graham.hobart (Graham stevens)
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ror

I wonder who that mug is you mentioned???
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  #14  
Old 17-07-2017, 03:49 PM
JA
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Quote:
Originally Posted by el_draco View Post
Building a R.O.R. a.t.m. and put the first of the rollers together today. That went well enough but has introduced a potential issue.

The roof itself will weigh in at about 250kg when done and I don't fancy trying to stop it if it builds up any velocity.... and really don't want to chase it down the side of the mountain where I am building.

It'll be automated at some point but does anyone have a basic breaking system design that I can use to start with. Don't really want to look at hanging weights, (for the obvious reason), if I can avoid it....

Rom
Hi draco,

If you are concerned about the roof rolling away too easily or building up too much speed, then you could simply increase the rolling resistance / friction by either, adding a couple of additional rubber wheels which are adjustable for preload and hence rolling friction on some part of the track, frame or roof structure or you could use a rubber pad with adjustable preload (even a nylon pad with enough preload) against which the roof would slide. Then when you are ready to automate your roof remove the speed limiting devices.

Best
JA

Last edited by JA; 17-07-2017 at 04:11 PM.
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  #15  
Old 17-07-2017, 04:07 PM
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multiweb (Marc)
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Quote:
Originally Posted by stefang View Post
Having just gone through the automation of a ROR process myself, here are some considerations to think of when the time comes to motorise your ROR

Ultimately you need to consider the following:
  1. What is the weight of the roof assembly?
  2. Do you require a solution for a single or split roof configuration?
  3. Do you need 24V or 12v etc
  4. Are you planning on using limit switches (magnetic, actuators etc)?
  5. Are you on grid or off grid power?
  6. Are you installing solar panels on the roof of the obs?

We initially installed a couple of Gate Opener units from Grays as below. We have a 1200kg unit on our south roof, and a 800kg rated unit on the Northern roof assembly. As we have 4 x 350kw solar panels on our southern roof, we needed something with some more torque to move the roof that drives a 6kw off grid power bank.

Gate Opener - Graysonline

About $399 including track

However, after a month or so of experimentation we swapped out the units for dedicated (60RPM) 12v motors. More torque, far lower power consumption, fully weatherproof and sealed geared motors with a keyed shaft.

120 Watt Geared motors. We sent the gearing from the gate opener unit off to a fabricator to have new gears machined from Brass so they are self lubricating.

About $119 for the motor+ $158 for the gearbox and mounting flange. New brass gears machined from stock were are about $190 bucks each

Ultimately budget, power source & reliability will be your key considerations.

If you are off grid keep in mind that the coils on a gate opener pull excessive power at start up. As our Obs is off grid we went with the smaller geared precision motors as they only pull 110watts, vs 500-600watts the coils alone draw when you activate the gate opener option. If you are off grid opening and closing the roof a handful of times can bleed your power store dry.

good luck
Stefan
Sounds like you did your homework and a lot experimentation on power consumption calculation including optimal material for the gears. Now thinking out of the box, I reckon a couple of starved wombats roped to the roof track with a food dispenser on the other end of the obs and a low consumption solenoid to open the cages flaps would do the job nicely too.
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  #16  
Old 25-07-2017, 09:27 PM
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el_draco (Rom)
Politically incorrect.

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Quote:
Originally Posted by graham.hobart View Post
I wonder who that mug is you mentioned???
What? who? no idea...
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