Beginner Sliding part along a slot

andrea_rossi972

Hi all,
I am a beginner using Onshape, I need some help using connectors.
I need to slide two parts inside a slot. 
In real life I will use a screw and bolt that I didn't draw in the project, is it needed for the  simulation?



This is my project
https://cad.onshape.com/documents/a0f869e61c6c33cd0522b063/w/4349afd763342f2947d28020/e/f1922c0705215285841acc98?renderMode=0&uiState=65d4645b6e18693b3dafc1e6

Can someone point me out how to achieve this?

Thank you very much and have a nice day !
Andrea

nick_papageorge073

You have all you need. Read up on "Pin Slot" and it will work.

andrea_rossi972

Thank you very much for your answer . 
Maybe I am missing something basic regarding the orientation of the mate connectors because I have erratic results, sometimes the connection works sometimes no. So I suppose I am clicking in the wrong place, maybe not paying attention to orientation or something like that.
In "ipotesi 1 " the movement seems to work even if I have red errors, in "ipotesi 2 " I am struggling in to find the right spot to activate to make the pin slot mate works

https://cad.onshape.com/documents/a0f869e61c6c33cd0522b063/w/4349afd763342f2947d28020/e/707e9dddb0666bd46e1e781b?renderMode=0&uiState=65d4dea016b649536361545d


Thank you !
Andrea

S1mon

Pin and Slot mates are tricky. The order of the mate connectors in the dialog controls which one is the pin and which is the slot. The orientation of the X-axis of one of the MCs controls the path of the slot. It always takes me a bunch of time to get these sorted out so that they do what I want.

nick_papageorge073

Take a look I redid the asm on the "nick asm" tab. https://cad.onshape.com/documents/ed74c189e3e12ca184318e92/v/a5f6a2de06d445321056d4ac/e/4a12209612742440b718cc84

Go through each part studio also I added and deleted some mate connectors at the bottom of each feature tree with notes in the feature name.

In the asm the lid is first "slider mate" with the base, on the "central mc's" I created. This keeps the lid both parallel and central to the base. Next are the arms. I'd get the arms working first, then add the washers at the very end. Rather than mate the arms to the washers.

The arms because they need to be offset each a different amount, I used cylindrical mate, rather than revolute mate. I think the revolte mate would have worked if the offset amount was perfectly calculated and entered. But with the cylindrical mate there is no need to worry about it.

Last is the pin-slot mate of the arms to the lid. Note the sliding happens about the X axis only. Set up the MC in the part studio with the X in the direction of sliding. When making the pin-slot mate in the asm, if it's sliding in the wrong direction, rotate the mate within the pin-slot mate asm dialog box. Hit the "play" button before exiting to make sure it's moving in the correct direction.

nick_papageorge073

By the way, if you suppress the "lid slider" mate in the asm, the lid will still go up and down and stay parallel to the base because of the arm joints. However, it could move forward and backwards within the box. That is how I believe this mechanism will work in real life. It needs additional joints if you want the lid to stay central to the base as it goes up and down. (I don't know what they are at first glance...). Maybe look at "scissor lift mechanisms" on google to see how they solved this issue.

eric_pesty

S1mon said:

Pin and Slot mates are tricky. The order of the mate connectors in the dialog controls which one is the pin and which is the slot. The orientation of the X-axis of one of the MCs controls the path of the slot. It always takes me a bunch of time to get these sorted out so that they do what I want.

Yeah they definitely take some getting used to...
I made a couple "tutorials" on mates including a couple specifically on pin slot to summarize what I learned over time, here's the part1 of the PIN slot:
https://youtu.be/-BuqWiO_qhE

@andrea_rossi972

andrea_rossi972

nick_papageorge073 Tomorrow I will study your example. Regarding the mechanism , you are right regarding the problem of the lid not staying centered. I made an "ipotesi 2" trying to address the problem making one connection secured and the other one free to slide in the slot  In my project  I used a hole, but the tolerance had to be perfect so I am thinking about using a full slot like "ipotesi 1" but with one of the arm fixed with a bolt ( so I can fine tuning during assembling)
Thank you