topic Re: Slider Joints in Fusion Design, Validate & Document Forum

Slider Joints

Anonymous — Mon, 31 Jul 2017 16:53:24 GMT

OK so, I am on a FIRST robotics team, and in my mechanical sub-team, our summer homework/project is to create a cascading lift, and I am having trouble using the joints and joint limits, as well as the motion link tool. And what I hve done so far is created a test lift design, I will attach it and another design I made to represent what I am shooting for because that design I created using another online CAD program known as Onshape, and I know, or believe that Fusion wikll do what I want it to do but I just don't know how to do it. The files will be attached. And perhaps I am wrong and that I am actually on the right track, but it is just hard for me to learn this all on my own and make heads or tails out of it. And the Onshape design isn't exactly how I want it I'd rather have it be similar to the fusion lift that I made. The Onshape file isn't going to show up the way I want it to but owell I guess.

Sincerely William K

Re: Slider Joints

jeff_strater — Mon, 31 Jul 2017 20:58:49 GMT

@Anonymous,

Your design looks fine to me. What, exactly are you struggling with? It seems like you have created the joints and joint limits correctly, and the motion link seems to work as I'd expect:

Also, the STEP design you attached seems to be just a subset of the Fusion design:

STEP file:

Fusion design:

Re: Slider Joints

Anonymous — Tue, 01 Aug 2017 17:49:25 GMT

Well the only problem is that it doesn't work the way I would want it to,
because on my Robotics team, our mechanical sub-team uses Solidworks for
their CAD designs, and I use Fusion because I don't have a computer that I
can install Solidworks onto. And in Solidworks the way my instructor had it
was that as the grey box tube goes up the carriage in between the two grey
pair of box tubing, goes up the same amount of distance. So lets say the
grey moves up 6 inches, the carriage also moves up 6 inches. But the grey
box tube has a resting position 6 inches offset relative to the red box
tube, although in the lift design, the rest option is left empty so that I
could leave it in a state without it going back to the 6 inch offset. And I
was curious if there is any other way that I could use that might make more
sense to me.

Re: Slider Joints

jeff_strater — Wed, 02 Aug 2017 04:05:48 GMT

Sorry, @Anonymous, I don't mean to be dense, but I'm still not quite getting what the problem is with the model you shared. Perhaps a video with some commentary could help us understand better.

you said:

"So lets say the grey moves up 6 inches, the carriage also moves up 6 inches. But the grey box tube has a resting position 6 inches offset relative to the red box tube, although in the lift design, the rest option is left empty so that I could leave it in a state without it going back to the 6 inch offset."

So, if I break that down, I interpret the first part to say that there needs to be a correlation between the joints Slider4 and Slider5, such that, as Slider4 moves, Slider5 moves the same distance. This is the Motion Link 6 that you have set up. When I looked at that, you had that link set up like this:

Which is close, but you probably want the two distances to be equal to satisfy your requirement, so I changed that so that both values were 2 in. (It doesn't matter whether both are 2, or 1 or any non-zero value). Now you get the motion that I think you want.

The second part of your statement refers to the resting position of Slider4. And, perhaps that is where the confusion exists. In Fusion joints there is the notion of a "rest" value for a joint. That produces kind of a spring or gravity effect on the joint such that, if you drag the the components, they will bounce back to their rest position. So, I suspect that is not what you want in this case, since you want to be able to drag and leave it in the dragged position. Instead, Fusion supports "joint limits", and it looks to me like you have these set up exactly correctly, so that the grey bar cannot go below 6 inches above the bottom of the red bar:

So, at least to my understanding of your description, other than the mismatch in the motion link, this model behaves exactly as you described that it should. That's a nice assembly!

Jeff

Re: Slider Joints

Anonymous — Thu, 03 Aug 2017 15:58:55 GMT

Ok Thanks, I appreciate it, you are right I believe, its just that at first it didn't make sense to me, but now that someone like your self has explained it I have realized that, that i the way it is supposed to be, which is ok since I'm still a little new to Fusion. Anyway Thank you for the help.

Re: Slider Joints

Anonymous — Thu, 03 Aug 2017 16:01:08 GMT

Re: Slider Joints

mika.takalo — Sat, 16 Jun 2018 08:46:58 GMT

Hello.

Is there some specific reason why the part which is jointed with a slider joint...sometimes moving by dragging on that specified axis, or sometimes it is rigid until you edit the joint measurements. (No, I wont share my design)

Re: Slider Joints

mika.takalo — Sat, 16 Jun 2018 09:15:46 GMT

Same thing with the pin slot joint, it is rigid after the making this kind of joint. It is not moving with dragging...

https://www.youtube.com/watch?v=_g5Nv9_iNDA

Re: Slider Joints

mika.takalo — Sat, 16 Jun 2018 09:16:49 GMT

This worked until the latest update...

Re: Slider Joints

mika.takalo — Tue, 19 Jun 2018 06:49:08 GMT

Any answers?

Re: Slider Joints

ryan.bales — Mon, 25 Jun 2018 19:44:07 GMT

Please create a new thread for this in the support board if you think there is an issue.