join problems

[Anonymous]

I'm trying to create joints so that the pushrod, servo horn and control horn move in unison, moving the elevator up and down. The frustrating thing is that I was able to get it to work before but I cant seem for the life of me to get it to work! I looked at my previous design, followed step by step and when I try to move it, nothing happens. If I remove one of the joints on the pushrod, the servo will move as well as the elevator individually. Please someone help me before I punch a hole though my monitor!

Thanks in advance,

Simon

[TheCADWhisperer]

Do you have design history turned on?

File>Export and then Attach your *.f3d file here.

[davebYYPCU · Accepted solution]

Revolve Joint on elevator hinge, to Stab

Revolve Joint on Control horn, to Pushrod.

Revolve Joint on Pushrod to Servo arm

Revolve Joint servo arm to output shaft. Set Joint limits to 60 degrees each way.

If this system locks up, all the shafts (Joint ) axis are not aligned.  

servo parallel to fuse sides, the obvious culprit, and both pushrod ends will need ball joints.

Might help....

[Anonymous]

It's my own design of an airplane so that's why it might look a little funny. 😉

Thanks,

Simon

[jeff_strater · Accepted solution]

@s.brooks2020 - I was able to get the mechanism to work by editing Rev18, and changing it from a Revolute to a Cylindrical joint type.  Sometimes that kind of edit can free a stuck mechanism if there is a bit of mis-alignment between components.  Screencast coming shortly

[Anonymous]

wow thank you so much Jeff for taking the time to look at the model! Now knowing to use a the cylindrical helps a lot, but if you do show me the screencast that would help a lot as well. 

Thank you!

Simon

[Anonymous]

Hey Dave, thanks for the input! I did try the ball joint and it does seem to work well. For my purposes it's perfect for what I need but I'm also interested to learning more on how the joints work so I'll look at Jeff solution as well.

Thanks!

Simon

[jeff_strater · Accepted solution]

never sure if a screencast is going to work or not.  Trying again.  If it fails, here is the link:  https://knowledge.autodesk.com/community/screencast/2ee3d311-d8a2-4bc5-954a-e82344e3df66 

[subversivespeed · Accepted solution]

Because often a joint may be offset or become offset somehow, I often use the ball type joint just to ensure it won't jam up. 

[Anonymous]

Alright, I'll keep that in mind. 🙂

Thanks!

Simon

[Anonymous]

Thank you Jeff for taking the time to capture and upload this video! I didn't know exactly where to put the cylindrical joint, but with the video it makes it very clear.

Thanks again!

Simon