Bell crank mechanism 2

[sudhakarn]

Hi folks,
I tried to define a bell crank mechanism in catia.I defined a revolute joint for the fulcrum and the lever.i defined a prismatic joint for the attached translating parts and a rigid joint to close the loop.could you pls tell me what are the joints i should be defining?

 

[jackk]

When I think of a "bell crank," I think 3 revolute joints.

Could you attach a picture of your bell crank mechanism, and highlight the joints you've defined.

 

[sudhakarn]

Hi jack,
Thanks for your reply.I have defined 6 parts in total.A fixed base,a bell crank lever hinged to it,two levers attached to the either ends of the bell crank,two supports on either side on which the levers slide through.
Revolute joint bw base and bell crank.
Revolute joints bw the levers
Prismatic joints bw the levers and the supports.
Rigid joint bw the supports.

Hope it helps.

 

[LWolf]

could you attach the model?

regards,
LWolf

 

[sudhakarn]

Hi wolf,
Sure.will do.

 

[sudhakarn]

Hi,
Please find the link of the video and suggest me how I can do it in Catia.

https://youtu.be/pSArG07naiU

Thank you.

 

[jackk]

I'm guessing your problems are with the prismatic joints in your sliders. The video shows the rods sliding through clamps that have a lot of clearance. (the video also shows the bellcrank is rotated through a fairly small angle, which helps to make it work)

CATIA kinematics is based on very precise mathematics; So, having extremely loose clamps might work in real life, but it won't work with CATIA. You need a slightly different design, if you want to animate a bellcrank mechanism similar to the video.

Here is one method you could use for each of the levers: Add a line to the lever, and add a point to the fixed base, and then use a Point-Curve joint. This will let the lever rotate as it slides back-and-fourth.

 

[sudhakarn]

Wonderful! Thanks a ton jack for your amazing insights. Will check it and get back.Thank you.

 

[sudhakarn]

Hi Jack,
You nailed it.Thanks a ton.I got it.This forum had been extremely useful for sharing the knowledge.Thank you Eng tips.