# restricted pivot - pikler triangle



## nirajshah31 (20 Feb 2020)

Hello
i'm designing a pikler triangle - you can google what is a pikler triangle
I wanted advise on how to design a pivot - see picture.

1) this pivot uses a bolt (red), which seems to allow a restricted movement between closed and open (to as is in the picture).
2) the black bolt is just used to once open it remains in place but isn't required for support/structure.

how is this made?
how can i add a feature that allows for opening to different angles whilst also maintaining structure & would the support then be on the bolts and how would i ensure it's secure & safe?

thanks
niraj


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## MikeG. (20 Feb 2020)

Welcome niraj.

That's a tiny image. It would help if you could upload a larger version so we could see what you are trying to ahieve.


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## nirajshah31 (20 Feb 2020)

MikeG.":9humrzg7 said:


> Welcome niraj.
> 
> That's a tiny image. It would help if you could upload a larger version so we could see what you are trying to ahieve.



added to original post


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## Doug B (20 Feb 2020)

The simplest way would be to have one bolt to act as a pivot & a second removable bolt that passed through corresponding holes around the circumference of the hinge that allowed the angles you required.

A thin metal plate fixed on both inside faces of the hinge that the bolts pass through would give added strength whilst not being visible.


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## Bm101 (20 Feb 2020)




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## nirajshah31 (20 Feb 2020)

thanks. I wasn't keen on this as it sticks out and is a potential hazard when using the climbing frame.


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## MikeG. (20 Feb 2020)

How about a rope between the middle of the two lowest "rungs", the ones lying on the floor?


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## nirajshah31 (20 Feb 2020)

Doug B":1xoy09xb said:


> The simplest way would be to have one bolt to act as a pivot & a second removable bolt that passed through corresponding holes around the circumference of the hinge that allowed the angles you required.
> 
> A thin metal plate fixed on both inside faces of the hinge that the bolts pass through would give added strength whilst not being visible.



do you have a picture pls? i'm thinking there are holes between the pivot bolt and edge of the round wooden disc? so the metal plate requires the same holes as the wood as it's sandwiched in-between?
thank you


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## Bm101 (20 Feb 2020)

Blimey. A climbing frame changes the dynamics somewhat. I presumed it was for drying washing etc. 
In your first picture the red bolt is the pivot. Both parts of wood can move freely. The black one is secured into the internal part. By cutting a curved channel in the outer part similar to the compass but at the top (Just under the red pivot) means you open the frame and gravity holds it open. No need to tighten any bolts etc.
With ghee scale of the wood being used you could engineer it to be mechanically sufficient or as Douglas suggested, use a metal plate on the internal faces.


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## Doug B (20 Feb 2020)

nirajshah31":17q4t7fj said:


> Doug B":17q4t7fj said:
> 
> 
> > The simplest way would be to have one bolt to act as a pivot & a second removable bolt that passed through corresponding holes around the circumference of the hinge that allowed the angles you required.
> ...



I don’t have a picture it was how I imagined I’d do this the easiest way I could, but you seem to have grasped what I’m thinking.
Doing it this way would lock off the hinge preventing any unwanted movement in the hinge during playtime use.
To keep the nut & bolt heads child friendly you could recess the nuts & bolt heads into plastic spheres which would also make them easier to grip so tighten securely. I’d also add a park position for the bolt, holes that correspond when the frame is folded flat which would help prevent loss of the removable bolt


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## nirajshah31 (20 Feb 2020)

Doug B":2hcj8ht8 said:


> nirajshah31":2hcj8ht8 said:
> 
> 
> > Doug B":2hcj8ht8 said:
> ...



OK got it!
Would i do this on both sides or just one side?
"I’d also add a park position for the bolt, holes that correspond when the frame is folded flat which would help prevent loss of the removable bolt"
I don't get it - Pls explain 
thank you!


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## Doug B (20 Feb 2020)

nirajshah31":35vcbisd said:


> OK got it!
> Would i do this on both sides or just one side?
> "I’d also add a park position for the bolt, holes that correspond when the frame is folded flat which would help prevent loss of the removable bolt"
> I don't get it - Pls explain
> thank you!



I’d do it on both hinges.
When the frame is not in use & is folded up for storage have a hole that when the bolt is inserted it holds the frame in that position which will also prevent the bolt from getting lost.


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## nirajshah31 (20 Feb 2020)

Understood - thank you!


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## nirajshah31 (20 Feb 2020)

Hi guys
Say I don’t want multiple angles but use the bolt to ensure the frame stays in that position.
Is there a way that the bolt isn’t the only support keeping frame open? But just there to ensure it doesn’t close.
So without the bolt gravity would keep it open.
That means there needs to be some sort of restriction to the pivot mechanism... how would I achieve that? So it allows from closed to 60degree open
Thanks


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## MikeG. (20 Feb 2020)

nirajshah31":3206zzpb said:


> ....... there needs to be some sort of restriction to the pivot mechanism....



Mechanically that is the very worst place for any restraint mechanism. I say again, how about a rope connecting the two frames at ground level? To try to do it at the pivot is just asking for trouble.


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## Bm101 (20 Feb 2020)

A straight arm will do for 1 angle. Out of use can hang down.
Are we getting a percentage if you sell these? :|


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## nirajshah31 (20 Feb 2020)

Bm101":38ezva2k said:


> With ghee scale of the wood being used you could engineer it to be mechanically sufficient .



Hi- please elaborate- ghee scale?! How would I engineer it to be safe without using a bolt?


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## Bm101 (20 Feb 2020)

Ghee... *the 
Typo.
Sorry.
Unless this is for a particular project you aren't telling us about, Mike has the easiest design by miles for a one off for your kids. Two bolts and rope. If its for something more involved then maybe share some knowledge?


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## nirajshah31 (20 Feb 2020)

Bm101":q5l1oyo7 said:


> A straight arm will do for 1 angle. Out of use can hang down.
> Are we getting a percentage if you sell these? :|



Oh yeah- a bar at the bottom.. I was hoping to keep that clear though.
This is just a project to make it for my son! Rather than buying/ordering from China!


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## nirajshah31 (20 Feb 2020)

Bm101":odxc3s7n said:


> Ghee... *the
> Typo.
> Sorry.
> Unless this is for a particular project you aren't telling us about, Mike has the easiest design by miles for a one off for your kids. Two bolts and rope. If its for something more involved then maybe share some knowledge?



Sorry- where would the rope go? How would it help to keep open?
I can only imagine the rope being useful when closed 
Ta


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## nirajshah31 (20 Feb 2020)

MikeG.":21yghs8s said:


> How about a rope between the middle of the two lowest "rungs", the ones lying on the floor?



Oh so this relies on gravity to stay open and restricted max opening by the rope.
Ah- thanks.
But I want to secure it staying open ... 
Ps rope isn’t Often child friendly


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## Trainee neophyte (21 Feb 2020)

nirajshah31":2u0lhoi7 said:


> MikeG.":2u0lhoi7 said:
> 
> 
> > How about a rope between the middle of the two lowest "rungs", the ones lying on the floor?
> ...



First of all, what does everyone else do? https://duckduckgo.com/?q=pickler+trian ... iax=images

There seem to be two camps here - best is a fixed, three sided triangle (doesn't fold, but is rock solid safe. This would be how I would go about it,given that my small, precious child is going to be testing this to the limits and beyond, especially when I turn my back for a moment.

The second option is a heavy bracket to protect the apex:




. 

My plan would be to make a three-sided triangle, and have it pivot at all corners so you could fix it as structurally secure in use, but fold it up to put away. In other words, make one more side than you were planning, with or without bars, which would hold it together.





Anything that could fold up with a toddler attached seems like asking for trouble, especially if you are answerable to the overprotective tiger-mum. I see why you want to make one yourself - these things are _expensive_.


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## nirajshah31 (21 Feb 2020)

Thanks for the reply.
Agree with your comments... but I want it to have 2 bars at the top so it can be perched upon
Must be foldable, safe and secure.
I saw this folding mechanism - but I am not sure how secure it is?!

Following this mechanism route, I was then thinking I’d add 1/5 circumference star (instead of the full star) and let it sit within a channel. This create my restricted pivot. Use a bolt to ensure it stays open.

I guess my two options to make it sturdy (assuming I still need to?!) would be
A) add another piece of wood at the apex (bolting to both sides)
B) add an arm to make a full triangle at the bottom.

Pls let me know your thoughts
Thanks


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## Doug B (21 Feb 2020)

If you don’t want adjustable angles then a triangular frame is the way to go either fixed or hinged so it can be folded up.
I definitely wouldn’t opt for rope or cord to triangulate it not for use with babies or very young children.


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## nirajshah31 (21 Feb 2020)

Ok. Just wondering how this one could have been made? Seems the arms slot into each other. Two pictures added


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## MikeG. (21 Feb 2020)

nirajshah31":24qc24ua said:


> MikeG.":24qc24ua said:
> 
> 
> > How about a rope between the middle of the two lowest "rungs", the ones lying on the floor?
> ...



OK then, replace the rope with two bits of wood pivoted in the middle. If one of them overhangs the pivot you could put a pin through and lock them into place.


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## MikeG. (21 Feb 2020)

Like this:


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## nirajshah31 (21 Feb 2020)

Thanks- I see what you mean.
I prefer not to use the bottom bar if possible.
See post #1337644


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## MikeG. (21 Feb 2020)

nirajshah31":21uw2ekx said:


> ......See post #1337644



And you see post 1337618.


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## nirajshah31 (21 Feb 2020)

Oooh- sorry missed that.
Thanks!
That design has been tested and passes CE/EU standards. So I assume it must work


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## MikeG. (21 Feb 2020)

nirajshah31":1jtl9xll said:


> Oooh- sorry missed that.
> Thanks!
> That design has been tested and passes CE/EU standards. So I assume it must work



It's manufactured in a factory. They have materials and tolerances you can only dream of. In a home workshop you will not achieve anything safe using the path you seem determined to follow. You aren't the first poster who has started a "how do I do this?" thread and only taken any notice of responses that support their predetermined plan. Well, sorry, but the course you are embarked on is the wrong one, and if you won't hear it, that's not our fault.

Good luck with this. I'm outta here.


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## nirajshah31 (21 Feb 2020)

Okay okay. 
Can I not at least understand the mechanism used.
And then as you say do something simpler in a home environment which is safe.


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## nirajshah31 (21 Feb 2020)

Figured out the mechanism. See pic

For the bolt holding it together- should it just be a shoulder bolt or should I have some sort of ball bearing to aid rotation inside the joint?

Thanks


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## Roland (23 Feb 2020)

I’ve just posted this in another thread, but here goes again.






After his trial assembly I cut a smiley curve across the triangle plate. Loosen the bottom bolt half a turn and you can fold the frame for storage. The wooden knob only has to be finger tight to hold the frame open. The bolts are M5 furniture bolts with a T-nut on the other side of the knob, and a “threaded connector” on the other side of the spar. The top bolt is filed exactly to length so that it anchors but doesn’t bind.


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## TheTiddles (3 Mar 2020)

As Mike had pointed out, you seem to be looking for confirmation more than critical review.

Putting the stop a few mm away from the pivot creates the most force on the smallest area, so is asking for a failure. Just because someone has done it, doesn’t mean it’s right, and a CE Mark doesn’t mean it’s tested for all eventualities.

A cord at the bottom of the triangle is the easiest option but I would never recommend it, as with a bit of slack you’ve created a ligature, not a good thing to have around little ones.

Mike’s bi-folding link could be quite elegant if you planned it well, or use the quadrant approach as also described.

Never pivot on a screw, but using a ground steel shoulder screw against wood is going to result in one of those materials coming off worse. Increase diameter to increase area and reduce pressure. 

Aidan


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## nirajshah31 (3 Mar 2020)

Hi Aiden
Thank you for helping - i do appreciate it.
So i want two dowels at the top rather than a centre one, therefore using the rounded top is aethetically pleasing. but then as you say i run into trouble.

So, i'll add a removeable bar to make it a full triangle, using hand knob screw or furniture screw - so 4 (one on each end). Will be a pain to remove but makes it safe.

Centre pivot - please explain what i should do. increase diameter of the hole vs screw... so M10 screw but hole of say 20mm? reduce pressure by using a plastic washer? pls explain in as much detail/ picture of the item as possible

thanks again - i am taking your advice on board


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## TheTiddles (4 Mar 2020)

Regarding the pivot point, it’s probably not worth fretting over (engineering joke, get it??!). A barrel bolt would give you a smooth head either side (or you could counterbore it) and a smooth surface to rotate against, they’re very cheap but you might have to buy 20.

If you use a third bar to complete the triangle, you could use a spacer between the two sides so the bottom bar sits between the angled sides (that is probably confusing, but draw out the layup and you’ll see, hopefully)

Aidan


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## nirajshah31 (4 Mar 2020)

Here’s my image with the bottom bar...


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## nirajshah31 (12 Apr 2020)

Finished it - thanks for your help all!


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