force analysis of anti-torque bar 1

[David Chen]

The blue bar is used to take the torque created by the torque gun when tightening a bolt.Please see the picture.The blue bar is in equilibrium under the couple and Fx and Fy force.The couple is created by the torque gun.The Fx and Fy are applied by the pivot pin.It seems not be able to create the equilibrium equation for the blue bar.Am I missing some forces?

 

[jlnsol]

Yes you missed another Fy force at the blue bar which force will be located at the torque gun position.
The two Fy forces you then have are parallel to each other and work in opposite direction.
They will create a torque equal to the torque of the gun but in opposite direction, so -20Nm
So then there is equilibrium
There is no force Fx. At least not caused by the torque gun.

 

[David Chen]

Thanks Jlnsol.There should be a force located at the torque gun.I made a test with my kid's Lego.I put the bolt on a XY slide which can move freely.When the motor started,the slide moved to the end stop.I have designed many systems with torque guns mounted on this kind of arms.I just can't believe the torque gun would take lateral load like this.I thought the torque gun was very expensive and shouldn't take any lateral load to avoid damage.But it does take lateral load and works well.So it is not as weak as I thought.