5 Replies Latest reply on Oct 5, 2015 1:00 PM by Philip Tsao

    Mating multiple tangent parts along a path

    Philip Tsao

      Hi All,


      I'm designing a part where there is a cylindrical piece sliding into a slot with a spring loaded backing.  There are also ball plungers that move while the cylindrical piece is sliding in and out.


      I want to be able to drag and move the cylindrical piece through the slot, but at the same time, I want the balls in the spring plungers to move when engaged, and I also want the spring loaded backing to move when engaged.


      I'm able to easily mate the two separately.  For example, I can make the balls tangent to the cylindrical piece and they will move appropriately (although I cannot drag the piece away from the balls).  Similarly, I can make the cylindrical piece tangent to the backing.


      I ultimately want to move the cylindrical piece anywhere within that slot and only have the tangent matings enable when it actually hits the balls or the spring loaded backing.


      Any ideas on how to mate this?  I've attached an image of the assembly.

        • Re: Mating multiple tangent parts along a path
          Jamil Snead

          I was able to get something that works pretty well for the ball plunger motion. I used a dummy surface that I constrained to the "cylinder" and set the ball tangent to. See my attached assembly file.


          The spring is much harder. For starters, you can't change the spring length using mates in the assembly. Or maybe I don't understand what you want the spring to do.

            • Re: Mating multiple tangent parts along a path
              Philip Tsao

              Hi Jamil,


              Great idea, that seems to work as I hoped for the ball.


              I don't necessarily need the spring itself to compress or extend.  But how do I add another mate onto your example such that when the cylinder hits the v-block, it then stays tangent for a certain limit distance?  For example, after I choose the spring, I can mate the v-block with a limit mate, indicating the furthest it can compress and extend.  However, when I drag the cylinder into the v-block, I'd like to see it move as expected as well.  The spring can be ignored in this situation.


              Thanks for your help!

            • Re: Mating multiple tangent parts along a path
              Andrew Deboer

              Its just 3 parts in a slot right? One spring at the end, two ball plungers, and the pin that slides?


              You should be able to create a sketch on the midplane of the pin that represents the tangent path of the ball, instead of a whole surface. You should be able to use that with a path mate between the pin and flexible ball plunger. Then you just need a limit distance mate between the pin and spring to set the distance. I would also use a midplane reference to keep the pin in the slot. The picture is only 2D, so I'm not sure how wide the slot is or if the ball plunger is always in contact in the slot, so I'm not sure how to mate it for the 3rd dimension. Mating it this way would keep the pin from rotating, but simplifies the mates a bit.


              On the sketch path, you need to make it longer than the part and put whatever limits and dimensions you need on it. Also make sure your sketch path is just longer than your limit mates or else it might freak out if you try and move it too far. Then just hide the sketch.