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Very interesting coupler

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  • Very interesting coupler

    I have been looking for a way to drive two rollers that will vary in the distance they are separated. I came across this type of coupler that I have never seen before. It is quite fascinating I think. This might be a fun little project to try to make in our home shops. You all have probably known about these forever but it is new to me.

    https://www.youtube.com/watch?v=G2DU1s2ukHQ
    Location: The Black Forest in Germany

    How to become a millionaire: Start out with 10 million and take up machining as a hobby!

  • #2
    Here is a lego version of the coupler.
    https://www.youtube.com/watch?v=2M9cp_lJ4_I
    Location: The Black Forest in Germany

    How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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    • #3
      Interesting but some couplings don't have a constant angular transmission speed. Don't know about this one.
      Helder Ferreira
      Setubal, Portugal

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      • #4
        Schmidt Coupling is described very well here- and appears to have perfect angular speed relationship ??

        https://www.youtube.com/watch?v=zVt1tvD7rqk


        Rich
        Green Bay, WI

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        • #5
          Originally posted by Noitoen View Post
          Interesting but some couplings don't have a constant angular transmission speed. Don't know about this one.
          When a coupling doesn't preserve rotation speed, it's usually because the input and output shafts aren't parallel. That's the case with "U" joints and even pairs of U joints.

          Ed
          Last edited by ed_h; 04-20-2021, 07:35 PM.
          For just a little more, you can do it yourself!

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          • #6
            BF if your mis-alignment is not that all severe just build an oldham coupling, much simpler and you can use self lubricating materials in the "sandwich disc"

            They are fun and very easy to make...

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            • #7
              Originally posted by ed_h View Post

              When a coupling that doesn't preserve rotation speed, it's usually because the input and output shafts aren't parallel. That's the case with "U" joints and even pairs of U joints.

              Ed
              And why constant velocity joints are used in front wheel drives where the rotational matching needs to be consistent across a wider angle.

              The Lego version of the Schmidt joint makes it very easy to see how it works. Not anywhere near as durable but a lot more clear how the links and middle plate function.
              Chilliwack BC, Canada

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              • #8
                Cakewalk to build, and they do cover a fair deviation range and unlike the schmidt you can also be off a little parallel wise between the drive unit and the driven...

                https://en.wikipedia.org/wiki/File:O...ated_small.gif

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                • #9
                  Originally posted by A.K. Boomer View Post
                  BF if your mis-alignment is not that all severe just build an oldham coupling, much simpler and you can use self lubricating materials in the "sandwich disc"

                  They are fun and very easy to make...
                  I have made a bunch of Oldham couplers. They work great where ever I used them in some misalignment situations.
                  Location: The Black Forest in Germany

                  How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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                  • #10
                    Looks like a high maintenance coupler. There are a lot of pivot joints there.

                    I wonder how long it takes before excessive lash becomes a problem.

                    Also have to wonder what the RPM limitations are.

                    JL............
                    Last edited by JoeLee; 04-20-2021, 04:18 PM.

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                    • #11
                      If you design it around a bag of 608 bearings it should last a while. I think it's an interesting solution for low torque low speed high misalignment.

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                      • #12
                        The Thompson Constant Velocity Joint looks interesting, can't really see how it works.
                        https://www.youtube.com/watch?v=UEvaOg7glKk
                        Kansas City area

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                        • #13
                          That Schmidt coupling looks like it would work well. But there sure is a bunch of parts there. And all those links will need to have the same hole spacing. Not really a problem, just need a bit of care. I am not sure, but I suspect it is a constant velocity design. There is no audio on the video clip, but perhaps a translation of the text there would answer that question.

                          One drawback I do see is that it probably does not allow any angular misalignment or surely not much. Any such angular misalignment would only be possible by some slack in the pivot bearings of the links (aka bad fitting). And there seems to be a limit to the amount of offset possible, due to the fact that the links must rotate 360 degrees without colliding with each other. So for larger offsets you would need to use larger base circles. But even that may be extended if the links were made in a "Z" shape so one can pass over the pivot point of it's neighbors.

                          But it is interesting and surely within the capability of most home shops.
                          Paul A.
                          SE Texas

                          And if you look REAL close at an analog signal,
                          You will find that it has discrete steps.

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                          • #14
                            Originally posted by Toolguy View Post
                            The Thompson Constant Velocity Joint looks interesting, can't really see how it works.
                            https://www.youtube.com/watch?v=UEvaOg7glKk
                            Well at least he corrected himself shot himself in the foot at 51 seconds into it, and the CV axle assembly is a marvel and handles EXTREME torque so is ideal for cars and always will be - and the friction he was showing is due to two things - they have slight pre-load and also he was running a boot, and the ball bearings inside don't "slide" they are ball bearings fer cri-sakes and the ones under pressure roll...

                            some go a half million miles and if they do create slight friction while turning who gives a crap unless their complete idiots and drive around lock to lock in circles all day long,,,

                            fact is - is they are efficient as all hell - pea shooter uses them and iv had trips of over 75 U.S. mpg's --- they are original along with boots and have over 150 k on them...

                            so --- unique and has special uses ? I'll give it that but pa-lease do not compare it to the almighty CV joint --- that thompson looks weak an anemic in comparison...

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                            • #15
                              Gentlemen, I just thought the mechanism was interesting. I certainly wasn't suggesting it was a replacement for anything or more efficient, better or anything else. CV joints are a wonder and won't be replaced by anything else in the near future I think. Now I do think that the joints in this picture are much superior to and Eco friendly and capable of transmitting huge torque and at many different angles. Click image for larger version

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                              Last edited by Black Forest; 04-21-2021, 02:07 AM.
                              Location: The Black Forest in Germany

                              How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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