having an issue with fastners

reg_neufeld

I have this drawing.  Its not so special but it is needing enough of the tools of onshape to make me spend many hours of trial and error.  I like how easy it is to assemble and make a model and have the movement.  I am wondering if its possible to connect my cylinder at both ends and have the action to move the grapple.  I will try to share the drawing here so if anyone has time to have a look.  I am actually building this project so I thought it would be fun to exercise to do in here and learn the program a bit.  I find it hard to assemble parts onto a flat surface at a point where you need them.  so in this drawing you will see I added a bunch of mate points to the grapple part so I could attach the cross bars.  Not sure why they have to stay turned on like that but that is another issue.
I have my cylinder working and hooked up at one end.  but when ever I try to joint the other point it rips the rod out of the cylinder and mates go red. I find when I am attempting to learn something like this and run into a wall I have a hard time moving on to more parts.   I was looking for a way to share the actual drawing but not sure how does not seem to be a way to save as. so this jpg might help understand my issue.

Narayan_K

@ reg_neufeld, by looking in to image,i think you have give "slider mate" instead of "cylindrical mate".

if so change the slider mate into cylindrical.

if not please make your document public and paste the URL here so that we can  look into that.

reg_neufeld

I had those as a slider mate.  That makes sense and will go give it a quick try.  The mate makes it more realistic but I still cannot mate the both ends of cylinder and have it all stay together.

https://cad.onshape.com/documents/17588240b195b4997245e7e5

reg_neufeld

I have a lot of little issues with this drawing and not sure how to correct them.  This is an exercise in making it as real as I can visually.  When I mated the grapple part to the bracket I used the revolute mate but I was wondering how it could be used and have the part sit in the middle of the bracket with a small gap on either side.   Right now it the grapple is against the sides of the bracket. played with cylindrical but it does strange things.

and the other thing is when I built the parts I maybe didn't use the correct planes or something but now when I assemble them they are not on any orientation that works in an assembly drawing.  So a top view really is not a proper square on top etc.

robert_morris

You can hide/show the mate connectors pressing the 'k' key or you can click the eye icon next to the mate connector just like you would to hide or show a part.

If you need to offset a mate, there is a checkbox in the mate dialog called 'offset'. If you check that, it will give you an option to enter a dimension to offset the mates.

Also, have you checked out this Onshape video (https://www.youtube.com/watch?v=U6ylOmmhLVI)? 
It shows connecting a cylinder up in a grapple similar to what you are doing and may give you some ideas for how the mates are done.

reg_neufeld

The video was cool and is pretty much just what I am trying to do.  And the method is what I have been doing except theirs works and mine will  not.  I have tried to build more of it in assemblies then bringing them together to attempt to mate but no luck.  starting to feel like a panda breeder not much success

if all my parts are not perfectly in line will that make a difference.  I will spend some time looking at some of the dimensions or build a new base but really don't see how that will effect it. this is what I get after doing the third revolute mate in what ever order I have tried which is most of them 4 times. 

reg_neufeld

robert_morris said:

You can hide/show the mate connectors pressing the 'k' key or you can click the eye icon next to the mate connector just like you would to hide or show a part.

If you need to offset a mate, there is a checkbox in the mate dialog called 'offset'. If you check that, it will give you an option to enter a dimension to offset the mates.

Also, have you checked out this Onshape video (https://www.youtube.com/watch?v=U6ylOmmhLVI)? 
It shows connecting a cylinder up in a grapple similar to what you are doing and may give you some ideas for how the mates are done.

I like the offset deal that tip was good,   but as far as turning off the mate connectors I added does not seem possible as I have them turned off in the parts studio where I created them but they still always show up.  That said I noticed them in the tutorial where I learned to use them so maybe its just an issue that maybe will get fixed in future updates.  I will try hard not to use them as they annoy me and with the offset option should be much easier to do.

noa

@reg_neufeld I made a copy of your document and did some work on the mates. The link to my public copy is here. You'll find that you still don't get the motion you want but that's because the linkage locks up. If you play with the dimensions of your pivot points, it should work out.

The key to what I did: I went into the part studio of the piston and added my own mate connectors in the middle where they'd join together (see below picture). I used the Mate Connector feature and changed it to "Between entities." This let me place a mate connector between the two faces. Then, this mate connector gets brought into the assembly and you can add a revolute mate between them.



p.s. I also replaced your many fastened mates with group mates. Grouping parts is a great way of making parts static relative to one another.

reg_neufeld

Thank you for your time.  I see the group mate is nice and keeps things much simpler and the between face option for placing the mate is what I thought should be available just didn't see it again.  I guess I need to figure out proper arc that is required to make model move realistically.  No real idea how to do that in here as there seems to be no option to measure points in the assembly sheet and in my parts studio I did not build parts relative to others where they would actually fit. Again thank you for your time I have learned a lot in the last few days.  

reg_neufeld

Well if anyone else needs to do this or has an issue I finally managed to make it happen.  I was making some different parts and redoing some I didn't like and when I went to reassemble I thought it would be insane to so it all the same and expect different result so I made the last mate from cylinder rod to cross member a cylindrical mate instead of using the revolute mates I was messing with.  And it all works good now.