single or double shear? 1

[c0rd0bes]

Hi gents I am a mechanical tech a little rusty on my theoretical side, can anyone answer this for me please.

I have two round hollow steel sections suspended at one end verically and carrying a load at the bottom end SWL 150kg. one section slides into the other for height extension and held in place by use of a pin through both sections.

My question is would the pin be thought of as having 2 shear loads or is it in double shear?

I am sourcing and buying alternative replacement positive locking pins and want to spec correctly as it is part of an assy with a SWL of 150kg.

Many thanks

 

[ivymike]

http://www.timber.org.au/ewebeditpro4/upload/Shear_planes_Type_1(1).jpg

does that help?

 

[desertfox]

Hi c0rd0bes

The pins are in double shear.
Have look at this site, you will need to scroll down a bit but it shows a bolt in single and double shear.

http://www.roymech.co.uk/Useful_Tables/Screws/Bolted_Joint.html

desertfox

 

[Ron]

Yep...double shear.

 

[EngineerTex]

It is double shear, but be careful. If there's even a slight gap between the faces of the parts then it's no longer simply in shear -- it's in bending. In other words, if the inner tube is not fairly tight inside the outer tube, then the pin is in bending and that's quite different.

Engineering is not the science behind building. It is the science behind not building.

 

[hokie66]

Tex is correct, but there doesn't have to be a gap between the faces. Because because part of the pin is in free space, there is a moment which must be considered. The pin should be designed using provisions for pins, not bolts.

 

[desertfox]

Hi c0rdbes

Here is a better reference:-

http://courses.washington.edu/mengr356/daly/pin-joint.pdf

Also the formula are the same whether its a pin or bolt, however with the bolt you have to use the plain shank dia for calculation purposes.

desertfox

 

[c0rd0bes]

Hi all a bit bellated but thank you all kindly for the replies they were invaluable and helped greatly

thanks

c0rd0bes

 

[desertfox]

hi c0rd0bes

Your welcome

desertfox