[AT] Saturday night amazement

[Jim Becker]

If you look closely at the spatial relationships between each shaft, the counterbalanced crank (whatever the proper term), the link to the V shaped part and the relevant leg of the V, you can see that at any position within a rotation, the relationships for both shafts are identical.  Thus they will always rotate at exactly the same speed.  The vertical movement of the V shaped part is close to a sine wave.  I have made no attempt to verify it as exact.  It probably varies somewhat in the way an IC engine piston varies from a sine wave.

An interesting note, there is no magic about the 90 degree angle.  The same thing can be done with the shafts at any angle as long as the V shaped part has the 2 legs at the same angle.  The shafts can be offset vertically as well.  You can even put the shafts at 180 degrees.  In that case, it becomes a reverser.

Jim Becker

From: Stephen Offiler 
Sent: Saturday, October 30, 2021 4:20 PM
To: Antique Tractor Email Discussion Group 
Subject: Re: [AT] Saturday night amazement

Watching it again a few more times, I think you're right, Bob.  It does look smooth.

SO


On Sat, Oct 30, 2021 at 2:14 PM rbrooks at hvc.rr.com <rbrooks at hvc.rr.com> wrote:

  Steve 

  The mechanism seems to run very smooth looking at the video. I would think that to handle large amounts of torque the mechanism would have to get large. Bevelled gears would be smaller and lighter IMHO

  Bob


  Sent from my iPhone


    On Oct 29, 2021, at 2:05 PM, Stephen Offiler <soffiler at gmail.com> wrote:


     
    I'm wondering whether the output rotation precisely matches input, or whether it's "lumpy" i.e. speeding up and slowing down at different points in the travel of the mechanism.  It seems like it would be cheaper to manufacture than bevel gears, which suggests it would have eventually prevailed in the market if it didn't have some flawed characteristic. 

    SO




    On Fri, Oct 29, 2021 at 1:56 PM Ken Knierim <ken.knierim at gmail.com> wrote:

      Good point, Tom. Seems a tough way to do it (unless a patent was involved). Wouldn't it be easier to run the shaft a little longer on one side (drive or driven, pick one) to put the bevel gear on the far side rather than the near side to get that reversal? (hopefully that makes sense). 


      I seem to recall Dad talking about guys making hayrakes from trucks and flipping the axle over to reverse the drive direction so they had 4 reverse gears instead. 


      Ken in AZ



      On Fri, Oct 29, 2021 at 10:08 AM Tom Martin <tmartin at xtra.co.nz> wrote:

        They were developed to keep shafts in same direction of rotation...

        Bevels gears reverse the secondary shaft.

        Tom

          On 24 October 2021 at 14:12 Brad Loomis <brad.loomis at gmail.com> wrote: 


          For you belt guys, I found this thing mesmerizing.  
          https://www.facebook.com/groups/56806961770/permalink/10158137279546771/ 

          I never...
          Brad
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