New Waver clamps design wanted

[Elli_97]

Hello :) (sorry for the bad english, but i really am in need of help)

I currently attend a mechanical school in Austria and have to design a new clamping unit for a lid.
The circular lid is loaded with a force of 60kN (the force acts on the center) and clamped with 4 units.

The currently existing units are equipped with star-shaped grips which have to be turned clockwise to clamp the lid.
The problem here is the particle generation of the thread.

Therefore, i am looking for another solution, which can applie the force needed to clamp the lid, but without the particle generation.
It has to be a manually operated solution.

I am thankful for every kind of advice you can give me and am thankful for you spending your time helping me.

 

[berkeman]

Welcome to the PF.

The circular lid is loaded with a force of 60kN (the force acts on the center)

Yikes, that's a lot of force! What is the application?

Can you post a picture and mechanical drawings of the current solution? And since this is for your schoolwork, please tell us what your initial thoughts are and what you have found in your searching so far.

 

[Dr.D]

You might want to consider a toggle clamp. But be aware that any mechanical clamp is going to have wear, and wear generates particles. Perhaps you can locate most of the wear below the level of the opening, so that gravity will move the wear particles away from the opening.

 

[Elli_97]

It's for some kind of waver bonding, I wasn't told the exact use of it.

Initially, a toggle clamp was my conclusion, but i should come up with as much solutions as I could, so that I have a variety of options where I can choose the best suited one for this application, preferably one with as little particle generation as possible because the lid which has to be clamped is located inside a cleanroom, therefore it should have as little as possible.

Sadly, I can't post any pictures because of a confidentality agreement, but it does look kind of like this if this is helpful

The current solutions grips are located next to the lid and have to be pivoted to it. Then it can be clamped

Thank you for taking yout time to help me with this, it really means a lot to me and i really am gratefull

 

[JBA]

Assuming this is a pressure container, it would help to know whether the cap seal requires any compression by the cap's retaining fastening system or is a bore (i.e. o-ring, cup, etc) type seal that is self energizing.

 

[Elli_97]

This is a photo i found that has a really similar design to the one i am currently working on.
Would you think that swing clamps could work. Or if I swap the current materials for the nut and bolt with some composite

 

[Rx7man]

Not sure if it would work for your application, but since this looks like a pressure cooker, how about looking at other types used there, perhaps different, stronger materials will need to be used.. I'm thinking of the type where you turn the lid and it tightens down in 1/16th of a turn or so.. Just another thought.

 

[Elli_97]

Hello and for the first time many thanks for reading
I have already asked something similar, but now I have a picture which helps to better understand what I mean.
Below is a lid which is loaded (in my case, which is similar to this) with 60 kN and the 4 clamping units keep the lid closed while a process is happening inside.
I have the task to find other clamping units, which are also manually operated, but have less to no particle generation compared to the star grips and threads.

What would you experts recommend? And again, thanks for reading this

 

[.Scott]

I assuming you mean 60KN/M^2.

Is this similar to what you are looking for:
https://www.jnequipment.com/shop/pa...MIgbGtiqaE1gIVGZ7ACh006wJ-EAkYCCABEgJ4W_D_BwE

 

[berkeman]

I have already asked something similar, but now I have a picture which helps to better understand what I mean.

I've merged your two threads -- please do not start a new thread on the same subject. Thank you.

 

[JBA]

One alternative you might consider is a rotating "breech lock screw" interlocking thread design with appropriate hardfacing on the contacting dog faces.

For a typical example of this type of design using a separate locking ring used on autoclaves see:

http://www.wsfindustries.com/rapidoor.html

 

[Tom.G]

Redesign the threaded clamps to use a ball screw with circulating ball nuts (follower). Add a sealed thrust bearing at the bearing surface between the clamps and lid. If needed, the pivot point of the clamps (where they attach to the vessel) could have sealed roller bearing installed. This would probably not be needed because there is very little force on them when they are pivoted out of the way.

 

[Elli_97]

Yes it's quite similar to the one I am working on and the 60kN consists of all forces already summarized

 

[JBA]

If I understand the direction you are going; then, one issue with a ball screw design for the screws is that it will require a locking feature on each screw to keep the screws from backing off under load. i.e. It is the friction on normal screws that prevents them from loosening under load.

 

[Elli_97]

The reply is coming quite late but thank you for your good advice.
One question I still have is about the locking feature for the screws.
How can this be designed, or are there any websites where i can gather some information about it.

 

[Tom.G]

One question I still have is about the locking feature for the screws.
How can this be designed, or are there any websites where i can gather some information about it.

https://www.google.com/search?source=hp&q=pawl+and+ratchet+assembly

Or drill a few holes in whatever turns when tightening (the handles/knobs maybe), and insert a pin to hit on something, perhaps the body of the container.