topic Re: Constrain pin in curved slot in Inventor Forum

Constrain pin in curved slot

sbromley — Tue, 05 Jun 2018 06:18:53 GMT

Constraints AGAIN.

How do I constrain the movement of the plate shown below to just the extents of the bolt in the slot, as below?

Re: Constrain pin in curved slot

admaiora — Tue, 05 Jun 2018 07:20:13 GMT

Contact set or transitional constraint?

Re: Constrain pin in curved slot

EvanGu — Tue, 05 Jun 2018 07:23:38 GMT

Hi,

You can create a Rotational joint and set angular limits to constrain the movement.

Re: Constrain pin in curved slot

sbromley — Tue, 05 Jun 2018 08:27:37 GMT

Thanks I'm having a play with rotational joint. So far no end of entering limit angles will make it stop. It is free to rotate fully!!! I'll keep trying.

EDIT - Nope. Can't make it stop at the slot limits. I've tried every angle I can but it still spins around fully. I'm obviously doing something wrong.

Never mind, thanks for the help.

Re: Constrain pin in curved slot

IgorMir — Tue, 05 Jun 2018 09:11:22 GMT

Hi sbromley;

Try to use an angle constrain. Just like on the attached video.

Cheers,

Igor.

Re: Constrain pin in curved slot

sbromley — Tue, 05 Jun 2018 10:35:51 GMT

Thanks all. I've somewhere near. Not perfect and certainly not as intuitive as I'd like.

Re: Constrain pin in curved slot

jhackney1972 — Wed, 06 Jun 2018 02:38:05 GMT

If you want to make it stop when the pin hits the end of the slot, on each end, you can remove the angle constraint, leave the rotation joint and simply add a "Contact Set" to the assembly. You select each part, in turn, in the browser, right click on it, and select "Contact Set". Then select the Inspect tab and choose "Activate Contact Solver". When you manually drag the component, it will stop when the pin hits the end of the slot. You can also "Drive" it if you need to.

One note here, the Contact Solver uses a lot of resources so you do not want to leave it on all the time when not needed.

Re: Constrain pin in curved slot

kelly.young — Wed, 06 Jun 2018 19:13:52 GMT

Hello @sbromley if the Angular Constraint and Joint Constraint with Limits aren't working like you want (you can try to create planes through the slot end centers to orient the angles more easily) you can try using the Transitional Constraint between created surfaces.

Here is a short screencast going over how to achieve this.

Hope that helps!

Please select the Accept as Solution button if a post solves your issue or answers your question.

Re: Constrain pin in curved slot

WHolzwarth — Wed, 06 Jun 2018 21:01:31 GMT

Pardon me, guys, but I've seen only simple stuff here.

Moving a pin along an arc with angular limits is not the goal. The path can be a complex curve, and it should be possible there, too.

I don't trust too much in contact set, it's flipping with fast mouse movements. But several years ago I found Rusty Belcher's train movement along a curved path:
https://www.youtube.com/watch?v=cjkgEqTpeSk

In the attachment I did similar for a pin along spline curve move, running in Studio.

But I've been struggling for a long time with attempts for changing an already placed startup value of an animated parameter (1mm to 0 mm in this sample). I didn't succeed.

That's driving me mad !

Re: Constrain pin in curved slot

kelly.young — Wed, 06 Jun 2018 23:07:09 GMT

Hello @WHolzwarth thanks for attaching the example. You would have to go back to the initial inception of the DriveMe parameter under Slot.ipt and change it to 0mm there.

This also changes the overall length to drive shortened by 1mm, but with a spline it is hard/not possible to define with dimensions for an overall length parameterically. If you could use arcs with tangent curve intersections for arc lengths and set up a combined length User Parameter.

Not sure if that helps but thought I would mention.

Re: Constrain pin in curved slot

sbromley — Thu, 07 Jun 2018 06:40:18 GMT

Looks like the way to do it I'll but try. Never used the surface feature before.

Re: Constrain pin in curved slot

WHolzwarth — Thu, 07 Jun 2018 07:11:12 GMT

@kelly.young schrieb:

.. You would have to go back to the initial inception of the DriveMe parameter under Slot.ipt and change it to 0mm there.

Thanks Kelly.

I tried your proposal of my own yesterday, but after some editing it was not possible. Perhaps it's not editing-proof; I'll watch further.

Another attempt this morning could change the start back to 0 mm. Perhaps a re-boot would have helped yesterday.