Offset clamping force

[UGMENTALCASE]

Evening all,

I've been working on some clamps, and although they have been tried and test (previously, we are reusing) it got me wondering. How would i calculate out an offset clamping force. I've attached an image as an example. So if i applied a tightening force on the nut what would be the applied force on the end of the hook. There is no tightening force, it could be anything for the pupose of this example.

Thanks in advance, i need to keep my brain working otherwise it stops and i can't figure this sort of thing out!!!!!!

 

[KENAT]

Your link doesn't seem to be working, if it's the kind of clamp I think you mean, then it's a simple fulcrum/lever problem.

Posting guidelines faq731-376

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(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[3DDave]

Another file post with non-allowed characters. In this case it has "+" signs in it. I don't know why the upload software accepts these or fails to change them to acceptable characters.

 

[UGMENTALCASE]

Sorry everyone didn't even notice the + signs in it. They've now been removed.

I've done work previously on the lever type, where you pivot in the centre and have 1 to 1 clamping force. Then in some instances you can't get the pivot in the centre either the force or the clamp end moves and calculate that out. Think this one is a little different.

Cheers

 

[kiwitom235]

I think this should help you...

http://www.wtools.com.tw/Relation-Formula.shtml

Bolt torque vs axial tension.

 

[KENAT]

If you can assume that the 'hook bolt' has minimal deflection then I think you can treat it as if it was a regular bolt holding it down.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[rb1957]

draw a free body. clearly there is a moment at the nut, and bending in the body of the hook. what's the issue ?

another day in paradise, or is paradise one day closer ?

 

[UGMENTALCASE]

Hi

@kiwiton I have been on that page earlier however this is for calculating straight forces? I've been using that also. I think another way to look at it is like the attached. A rough sketch of my clamp.

 

[rb1957]

ok, sketch is clear, now draw the free body. you already recognise that the two clamp forces are not aligned so something has to balance this.

another day in paradise, or is paradise one day closer ?

 

[UGMENTALCASE]

Sorry I don't follow what you mean by draw the free body?

 

[rb1957]

oh dear, surely you've heard of "free body diagram" ? maybe google it ...

another day in paradise, or is paradise one day closer ?

 

[UGMENTALCASE]

Ok yes i had sketched that out earlier whilst i drew up my forces etc

 

[rb1957]

so you're GTG ?

another day in paradise, or is paradise one day closer ?

 

[SnTMan]

No. I won't...

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[kiwitom235]

Hey,

I think you should just simplify it and not assume there is an offset between 'clamp point' and 'bolt point'.

I dont have any experience with this type application, so I am a bit like you, but I would suggest the offset is minimal compared to the torque and axial forces.

Basically, the torque applied by the nut will be transmitted through the curved clamp and back into the base material.

Tom



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Hi

@kiwiton I have been on that page earlier however this is for calculating straight forces? I've been using that also. I think another way to look at it is like the attached. A rough sketch of my clamp.

http://files.engineering.com/getfile.aspx?folder=597ffefd-6441-4627-ab70-c6

 

[JNieman]

If this is a critical item, I would suggest hiring an engineer to evaluate your product.