UKC

I have the holds for a 12 x 12 system board arriving soon and would like to be able to use it at different angles (and because of the shape of the room I’d like to have it out of the way some of the time at around 15 deg). Does any one have any experience of designing/ building their own tilting setup? Any experience of incorporating a winch or mechanical tiling mechanism? Any advice would be much appreciated. Thanks in advance…

In reply to Adam Booth:

Hi Adam, Yes I've built a tilting board in my shed. It's a 4m apex pitched roof so the angle defaults to 25 degrees. I'll dig out a photo but essentially I used stainless steel fire door hinges 

https://www.ironmongerydirect.co.uk/product/enduro-twin-ball-bearing-fire-d...

I used eight of these - I could have used less but I figured over engineer the thing! Four is probably enough. 

The winch is just a cheapy one from Amazon. I use chains on either side for when climbing on the frame because the winch wire is stretchy and the climbing wall twists without them. The winch was strong enough to lift the wall from horizontal. Pulley's are cheap Chinese ones from Amazon. Bolts and hangers go through the two by sixes. 

In reply to Adam Booth:

12x12 is going to be a big, heavy and potentially quite wobbly board.

Normally on these threads I'm the voice of don't overthink it, do make it adjustable and no, it doesn't need to be that heavy but a 12x12 board moving as one piece, that does need some proper thought to the engineering. You really need to think about how it's supported and what keeps it/you/the building safe if there's a failure or it gets away from you. You're looking 250+kg with a decent set of holds on  it.

As you say it'd never go up past 15deg you have plenty of room behind to work with. As ever I'd look at building the structure quite light and add a pyramid of triangulation behind, that'll stiffen the surface and control twisting for very little added weight. You also have room back there for counterbalancing*. Balance it light enough to move manually, keep the counterbalancing redundant that way it can't get away from you and break/hurt anything even if part of it fails.

Engineered joists are probably worth a look if you prefer a more traditional, lots of deep joists type construction. eg https://www.jtatkinson.co.uk/i-beams-i-joists and a second skin on the back of that type of construction, even a thin one will massively increase the twisting resistance.

* loads of options from simple and elegant weighted tie-backs, through weights or springs via pulleys to something like a roller-shutter torsion spring.

jk

In reply to jkarran:

You're looking 250+kg with a decent set of holds on  it.

My 8x11 was lifted with a 125kg lift which picked it up from flat at a 45 degree angle of pull (at the 2/3 point. And then lifted it with holds from 45 degrees. So I would estimate that the board was hovering around 200kg. 

2.6 is about .7kg per foot for a weight of 5.6kg per length of board. I used five lengths and two ends for a weight of 40kg max. Each sheet of plywood is approx 28kg hence my three sheets were 84kg and holds (moonboard three sets) were about 50kg so... 40kg + 85kg + 50kg is approximately 170kg and my pulley would need to lift half of that for about 85kg

For a 12x12 board you can scale that up by 1.8 so approximately 300kg. At a 60 degree angle (very steep), this would be a force of half that ( assuming angle of pulley intersects at about 90 degrees) so 150kg (you'd need a bigger winch). Split across two chains would have 75kg per chain. 

Obviously throwing yourself around on it would apply a fair bit extra. Lets say double your weight max. At 45 degrees, you'd apply about 70% of your weight on the chains so lets say 80kg weight, doubled = 160kg 70% makes that 112kg extra. So each chain anchor would need to hold half that which will make it 85kg + 60kg = 135kg. 

So your chain anchors would have to take about 135kg. add 50% for a minimum safety margin and you have 200kg per attachment point. That's not going to work attaching to single studs so you'll need to span quite a few studs. 

In my opinion you'll need to get into the roof space and attach the chains and winch to the roof. If you're wall is parallel to roof joists, you'll be OK I would imagine but if it's 90 degrees, I'd want to put in a beam that spans multiple joists. A healthy ceiling joist should easily hold that, an 80kg person jumping up and down would hit that easily.

I'm not an engineer but given the specifications, I think I'd be happy with that..

In reply to timparkin:

While the static/climbing forces certainly bear consideration my main thought was what happens, being so big, if it gets dropped, if a winch cable snaps for example. What stops that big wall before it hurts someone or pulls something bigger down with it? By having it quite well balanced by design, counter-balanced by redundant mechanisms that concern pretty much goes away plus you do away with the need for heavy manual lifting or a winch.

That's where my brain goes anyway when thinking how I'd move one big heavy panel around especially where you haven't got an absolutely bombproof structure to hang it off.

Actually I'd probably also split it into three (or more) panels for a bunch of reasons but maybe that doesn't fit with a 'system board', dunno.

It's certainly big enough that a good think about what it's attached to, what that's attached to, where the loads go ultimately and what could go wrong is well justified.

jk

This is the wall in my previous house. It’s obviously quote a lot smaller than you’re proposing.

What you can’t see is there was an electric winch behind with a pulley attached to the wall with resin anchor and threaded bar.

the wall straps are redundant (in terms of weight distribution) once the legs are in place.

In reply to Adam Booth:

Mine is much more basic, and fully manual - legs come from the wall and are secured at various points along runners to set different angles.

It is therefore a two-person job; one to support the wall, the other to adjust the legs to the new angle and push through the retaining bolts. It's only 2.4m square + all the holds, so pretty manageable.

Simple but effective. No danger of cables/chains/walls giving out and dropping a wall on someone.

In reply to jkarran:

What do you mean by a pyramid of triangulation? (I’m currently thinking through my next build)

In reply to Twiggy Diablo:

Adding a simple truss structure to the back of an otherwise rather flexible surface can add significant stiffness for little weight. In this case I'm envisaging the main triangles running corner to corner with the peak of the truss triangles tied back down to the climbing surface to stiffen it. Whether you'd need more than that, particularly at the board edges, would depend how lightly the basic board frame was built.

I'm not the right type of engineer so I'll probably describe this badly but as I see it you're adding structure (trusses) which make use of the climbing skin's stiffness in plane to improve it's low bending stiffness through the plane (by tying points on that bendy plane to the stiff triangulation behind).

If the wall had to fold back flat against the underlying structure a sandwich panel (or a traditional build with deep (6-8") framing may make more sense but where there is space available to add truss work it can be a cheap lightweight way to add stiffness.

jk

In reply to jkarran:

If you only anchord the wall in the centre, then I'd agree, there's loads of twisting forces that would be a pain and you'd have to have diagonal bracing .

If you anchor the wall at each corner (or close to the corner) then as long as the force isn't upward (it shouldn't be unless you have extra special anti-grav shoes) then the board can only flex in the middle. If you support the middle with the winch then it doesn't flex much at all (presuming chunky chains. If you want to add some extra strength, you could use 2x6 for your edge pieces to reduce 'bowing' 

You could also add a couple of planks of two by four wedged between the climbing surface and wall behind to stiffen it in both directions if you wanted. 

The quick and easy (although possibly more expensive) truss/diagonal bracing equivalent is to skin the rear of the board as well (I think you're suggesting this at the end of your post). You could get away with think plywood I imagine (it's only acting as a skin, mostly in tension/compression)

In reply to timparkin:

Yeah, there's certainly more than one way to skin a cat.

I'm cheap so I like structures that are mostly air, especially if I have to move them manually

jk