tightening pivot

[cole.hardcastle]

I am working out a design for a pivot which will heighten and lower a desk and have attached a simple image of what it will look like

what fixings/ types of pivots/ methods could anyone suggest this could be made? I want the to be able to tighten against the frame so it wont move, although there will be other supports

I have never done anything like this and I am a designer and quite the novice at manufacturing techniques

Any help peeps?

(edit. open to any materials, not just wood)

 

[oakmitre]

When you say lower / heighten, do you mean the angle of the desk as opposed to the height ?

The mechanism you have drawn puts the tightening bolt at the end of ( what I think is called ) a cantilever. Tightening it will not result in a stiff load bearing arrangement.

If you want a simple set of pre set angles then pegs can be used in the sides of the desk in various ways. Depends if you want infinite adjustment. I have attached an image of a disc / peg system which is used on piano keyboard stands.

 

[novocaine]

I'd suggest looking at 4 bar linkages, these will take the load far better than the single arm link you show. they are also a lot easier to lock in place by extending past one of the pivots and adding a locking nut and track.
they will also lift in a linear fashion and be far more ridged.

 

[cole.hardcastle]

here are a few more images of what I'm proposing

 

[cole.hardcastle]

When you say lower / heighten, do you mean the angle of the desk as opposed to the height ?

The table top will pivot round to a higher position, please see other images
I was thinking I could tighten up like a vice on each other side but am unsure how that would work

 

[Adam9453]

I'm puzzled by the design. Whats the reason for wanting the desk surface to be positionable at two different heights?

The way you have drawn it makes me think the back of the desk will be inclined to pop upwards when the front of the desk is leaned on (or sat on by someone), this would then transfer the load down to the front portion of the side braces resting against the legs but because they are so short it will I think just try and pull the mechanism apart.

Does the desk height need to be changed frequently or could you make the desk support structure separate to the desk table area. My suggestion is that if you only had to change it relatively infrequently then you could just make the table area so that it sits in deep grooves in the side frames. To change the height you pull it towards you and then slot it into the higher or lower groove (depending on which you started in). This would be nice and strong providing the length of the groove was substantial when compared with the depth of the removable desk area.

If you need to move it frequently then I would change the design substantially.

I'm sure someone else will be along to give their advice which may well be the polar opposite of what i've said lol

 

[oakmitre]

Wow !!

To be fair, that first image is just a bit simpler than the second set ! I like the way the desktop slides down the ramp.

Are you sure you are going to attempt this as your first project ? It seems fairly advanced. To make the frame sides themselves would require learning how to make some fairly complex templates and use a router to follow them. Of course if you have access to a laser cutter to make the tempates first, that would be a bit easier.

On the very end of the pivoting bar - you could still use a peg system, if the ends of the bars had an overlapping flange next to them (the side pieces) with holes in it.

Wow.

 

[oakmitre]

Ever noticed how two similar sized cardboard boxes can slot into each other and 'telescope' to make a platform with variable height ?

I would do it that way with a frame inside a frame - I know that is really boring - and totally not what you want lol - but that is how I would do it.

 

[cole.hardcastle]

The two different heights would be for standing and sitting, and I am fairly sure the structure will hold as the frame will be separate, and the desk top will pivot on each side supported by the diagonal ramps
and would only need tightening at the higher position if you get me, this design is still early days btw

Its not my first project but is my first with moving parts like this, I have access to a CNC so alls good lol

The peg system is something I will look into but I quite like the aesthetics on a vice handle/crank
A different idea I have thought of is having a 'gear rack' system to move up and down the ramp but figured it would take a long time to adjust and want it to be as quick as possible

Any idea on tightening? fixed on the inside
the only example I can think of is similar to a wing nut on a lamp? haha

 

[cole.hardcastle]

Ever noticed how two similar sized cardboard boxes can slot into each other and 'telescope' to make a platform with variable height ?

Not sure what you mean? sounds interesting though

 

[Adam9453]

The pieces resting on the 'diagonal ramps' are very short when compared with the depth of the desk. I think the leverage acting on the mechanism area will be very high, particularly if someone heavy decides to perch themselves on the edge of it. If you know better that's cool but I'd be concerned about the mechanics of your design.
Good luck with it and be sure to post pics of it as you build it.
How frequently do you intend do switch it between the two heights?

 

[cole.hardcastle]

Do you mean short as in the thickness? maybe will have to be thicker or the top smaller, I plan on counter weighting with back piece and shelving of some kind
I dont so good to get advice, just wanting to know how a pivot can tighten in place ha as i dont know

If all goes wrong it will just end up being a normal desk i guess but dont plan on rushing into it, project for back end of this year probably