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slider / pin / tangent mate thing

iain_downsiain_downs Member Posts: 22 ✭✭
Sorry if that's a bit vague.

I'm trying to model a kind of stevenson's reversing gear for a steam engine.  The idea is that you have a curved slot which has a pin in it (a more or less square pin) which can move along the slot.  I've tried a variety of mates to solve this all of which do thing I don't expect.  The image below should provide a basic idea.  The square bearing fits in the slot and cam move along it (actually, the bearing stays still and the slot is moved, but that's neither here nor there!)

The assembly is at https://cad.onshape.com/documents/6f64bbef3b1f362c146611c6/w/e4e4530f34830ec08b4282f7/e/f64dee45926b455eec4b535b entitled Valve Control.

Any advice would be much appreciated



  • john_mcclaryjohn_mcclary Member, Developers Posts: 3,253 PRO
    Tangent mate is what you are looking for. 

    You may want to consider sketching a path inside the slot center and insert that into the assembly for mating. 
  • iain_downsiain_downs Member Posts: 22 ✭✭
    Thanks, John.

    I've discovered I can make this work by first setting a planer mate so the bearing can only move in the plane of the slotted part and then applying a tangent mate between the top fir the slot and the top of the bearing.

    As a follow up question, how can I make the bearing stop at the end of the slot?

  • john_mcclaryjohn_mcclary Member, Developers Posts: 3,253 PRO
    Yes, Tangent will stop when it comes to the end of a face... I thiiink it will do the same for a sketch.. Though i'm not in a position to test it at the moment. 

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