# Balancing a horizontol flat surface when weight applied to one side

Thank you for taking time to assist me. I have a rectangular surface that i want to hang from it's 4 corner points. The corners on two sides could be joined together clipping on to a centre support beam (like in my excel drawing - sorry only software I have available) and then the support beam is hanging from a centre swivel hook which hangs from the ceiling.

My question is how would one achieving horizontal balance if a weight was placed off centre on the horizontal surface.

I can't use a vertical counter balance so have tried looking at linear counter balance. I have found some examples online but have no idea how this would be implemented here. I have no engineering knowledge so any assistance would be greatly appreciated. If you could even just tell me what I should be searching for.

Thanks]1

• It really depends on usage ot this part. If its shell maybe easiest would be to try adding weight eg. sliding track with one or two balancing masses. There are also solution with springs but You would need extended engineering knowledge to create those. Nov 27, 2017 at 6:57
• Do you just want a balanced table, or do we have to use the design you purposed in your drawing? Nov 27, 2017 at 12:43
• Is the weight that you're placing in a known/fixed position, or might this surface have the weight moved around on it? Are you forced to have a single hanging point as illustrated by your black line? Can this be rigid? Nov 27, 2017 at 13:41
• @h_uat Having a balanced table would be great! I don't mind the design changing Nov 28, 2017 at 14:50
• @JonathanRSwift The weight could be placed in different locations on the surface. I wanted a single hanging point as i wanted to be able to swivel the flat surface. It can be rigid yes. Thanks for the help! Nov 28, 2017 at 14:53

Instead of developing a complex mechanism to allow the surface to balance, you could support it by a rigid connection. Any deviation from horizontal will be opposed by the bending moment in the support.

You could use two bearings at either end of a tube (much like the headset on a pushbike) in order to allow your support to rotate, even when a bending moment is applied.

Imagine solidly fixing a bike frame to the ceiling, and then joining your Red Crossbar rigidly to the forks!

In the rough diagram above, the red head-tube is firmly fixed to the ceiling. The black forks are rigidly joined to the black crossbar, and the blue surface hangs from the ends of the crossbar.

This provides a single (and circular) fixing point to the ceiling (as you correctly stated is a requirement, but allows the system to remain rigid with respect to the off-centre mass on the blue surface.

• Thanks Jonathan! I think I understand what you propose in terms of giving it stability. Just with regards to the swivel action, not sure I explained this correctly. I wanted the surface to swivel horizontally. So lets say I have something on the left side of the surface I would turn the surface horizontally so the weight ends up on the right side. The only way I can think of achieving this is either by having a circular support or having a single final fixing point to the ceiling but I fear this would still leave me with a balance issue? Nov 29, 2017 at 6:34
• I think my idea still works for you? I've added a diagram to my answer to make it clearer what I meant - sorry was very rushed yesterday! Nov 29, 2017 at 13:01
• Yes that would definitely work. I misunderstood your earlier post thinking it was going through the front and rear forks..... As i said - no engineering knowledge! Thanks for your help! Nov 30, 2017 at 1:33