Four Bar Linkage Mechanical Advantage 2

[elsanchez45]

Hi,
I'm working on a crossed four bar linkage (see below - apologies for the crude drawing)
I'm able to calculate the position of all the elements during the motion, but I'm looking for any advice regarding how to determine the output torque (T2) from the input torque (T1)
Any help would be appreciated

 

[MintJulep]

The forces at points A and B will subject link AB to a moment.

The hinged joint A by itself, not so much.

 

[elsanchez45]

I agree. I need to work out what the moment acting on AB (around A) will be.
Resultant forces at A from T1 are easy enough to work out, but I'm getting myself tied in knots trying to figure out the reaction forces through CB which are imparting the moment on AB.
Any ideas?

 

[hydtools]

Do a free body diagram of AD and determine reactions at A.

Ted

 

[3DDave]

If you can calculate the kinematics of the linkage then look at the energy input as T[sub]1[/sub] times deltaTheta[sub]1[/sub] = T[sub]2[/sub] times deltaTheta[sub]2[/sub], which is energy output

Rearranging - T[sub]2[/sub]/T[sub]1[/sub] = deltaTheta[sub]1[/sub]/deltaTheta[sub]2[/sub]

where Theta[sub]2[/sub] is angle DAB.

If there are gravity loads then those have to be included and will alter available torque as they absorb or remove energy.

 

[elsanchez45]

Thanks 3DDave - that's exactly what I needed.