Apply mate in a sliding hardstop.

rodrigo_coppelli

Trying to make a rotational device with a sliding hardstop on both sides and wondering how to apply the mates. See onshape doc here: https://lgsstudent.onshape.com/documents/fa47e0824c2237ab8f9e321c/w/3ddf015425baa4e465e4d408/e/55b0eb73a00126c5a9ffdf7f?renderMode=0&uiState=653bfe274e90d9537ed806d7
I want to make a tab on the top rotating plate hit a sliding pin (blue) in a slot. That pin would then hit a hardstop at the end of the slot. At which point the top rotating plate can rotate in the other direction, hit the same pin and the pin slides to hit the hardstop on the other side. Any ideas on how to make this mate? I need to show it for a presentation, so if I can make the mates and animate it it would help my presentation

BenTaylor

I was able create this assembly with the limits working as you described. I created a mate connector at the center of the base that "belonged to" the pin. I used that mate connector to create a revolute mate between the pin and the base with the appropriate limits - this is the easiest way to create a pin-slot mate with a curved slot. To add the top rotating plate, we create a revolute mate between the plate's center point and the created mate connector that belongs to the pin. This assignment means that we can create rotation limits for the top rotating plate relative to the pin's position, not relative to the base. We can set the limits for that revolute mate so that they collide without interference.
The resulting assembly generally works as you've described. When I move/rotate the parts, they will usually follow "natural" behavior but sometimes become "sticky", where the parts move together without a natural collision/behavior. I'm not sure what triggers this behavior, and don't think there's an easy way to prevent this with the way Onshape's assemblies work. It's not perfect, but hopefully helps you get towards what you were looking for.

glen_dewsbury

Can you make this document public so it can be saved for samples. As a link it is view only.

rodrigo_coppelli

Oops! Yeah, that would be helpful. I clicked on "Link Sharing" and then it only allowed me to add "Export". I think that will allow you to make a copy right? Thanks for checking it out

BenTaylor

I was able create this assembly with the limits working as you described. I created a mate connector at the center of the base that "belonged to" the pin. I used that mate connector to create a revolute mate between the pin and the base with the appropriate limits - this is the easiest way to create a pin-slot mate with a curved slot. To add the top rotating plate, we create a revolute mate between the plate's center point and the created mate connector that belongs to the pin. This assignment means that we can create rotation limits for the top rotating plate relative to the pin's position, not relative to the base. We can set the limits for that revolute mate so that they collide without interference.
The resulting assembly generally works as you've described. When I move/rotate the parts, they will usually follow "natural" behavior but sometimes become "sticky", where the parts move together without a natural collision/behavior. I'm not sure what triggers this behavior, and don't think there's an easy way to prevent this with the way Onshape's assemblies work. It's not perfect, but hopefully helps you get towards what you were looking for.