Issue with bevel gear reversal on linkages

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BillM
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Issue with bevel gear reversal on linkages

Post by BillM »

Art

This issue has a deja vu feel to it.  Attached is an issue I thought I ran across a while ago.

I created a bevel gear and added it the project as master.  I then reversed the bevel gear and added two other spur gears on either side of the bevel gear.  When I run the simulation the spur gears run in reverse to the bevel gear.  I don't suppose this was the intended effect of reversing the bevel gear.


A quick work around is to then reverse each of the spur gears which at least has them turn in the same direction of the bevel gear.

When the bevel gear is added it links to the shaft.  The shaft then links to each of the spur gears.  It would appear that reversing the bevel gear reverses the rotation bevel gear but does not reverse the direction of the shaft.

Bill Michael
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ArtF
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Re: Issue with bevel gear reversal on linkages

Post by ArtF »

Hi Bill:

Yes, I do recall this as an issue, a fix was applied and had to be removed as it made another operation similarly difficult
as I recall. Lets call that one a feature. :)

Art
BillM
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Re: Issue with bevel gear reversal on linkages

Post by BillM »

Art

Thanks for the reply.  I'll add it to my notes under undocumented feature.  At least I have the work around that is simpler than trying to manually relink gears.

Bill
BillM
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Re: Issue with bevel gear reversal on linkages

Post by BillM »

Art

I stumbled across another oddity regarding the reversing of a bevel gear. That is illustrated in the attached two gth files.

In the first, I added a bevel gear and then added the ratchet as a wheel to the shaft of the bevel gear.  Things look OK.

In the second, I added a bevel gear, reversed it, reversed the shaft and then added the ratchet as a wheel to the shaft of the bevel gear.  This sequence results in the pawl being incorrectly placed next to the ratchet.

If I don't do the shaft reversal, the ratchet will rotate reversed from the bevel gear but the pawl is correctly positioned. Having the ratchet rotation reversed from the bevel gear is not good.

The reversal of the shaft in addition to the bevel gear was a quick work around to make adding spur gears to the bevel gear shaft turn in the same direction as the bevel gear.  An alternative to reversing the shaft is to reverse each spur gear added to the bevel gear shaft.  This alternative correction does not work with ratchets/pawls.

This issue perhaps falls under the category of if it breaks gearotics then don't do it.

Bill Michael

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ArtF
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Re: Issue with bevel gear reversal on linkages

Post by ArtF »

Bill:

  Thx. I will note that one in case its an easy fix. I try not to change Gearotic much anymore,
its getting too old and long in the teeth...

Art
BillM
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Re: Issue with bevel gear reversal on linkages

Post by BillM »

Art

Seeing that gearotics is kind of old now perhaps just skip the problem.  Sometimes patching one problem creates side-effects that may not be obvious until much later.

It is easier to inform users not to use reversed bevel gears along with ratchets.

Do you think that the Augie vector processing will ever get merged into Vexx?  Vexx has many useful drawing features and I find it pretty handy to modify gears being designed in gearotics.  It would really be awesome to have the simulation abilities of Augie integrated with Vexx.

Bill Michael
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Re: Issue with bevel gear reversal on linkages

Post by ArtF »

Bill:

  In truth Vexx was started in order to remove vector processing from Auggie and give it a proper
cad platform. I kept finding things to add to vexx though and it became sort of a sandbox to deal with
vector shapes.

  I do already resist changing Gearotic, its compiled under 2013 and I try not to change it, as you say it
adds bugs. Its why Vexx keeps getting tools added to it. I may one day recode the physics module to use
drawings in Vexx, hard to say. 

Art
BillM
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Re: Issue with bevel gear reversal on linkages

Post by BillM »

Art

I'll monitor the Vexx topic area just in case you do get around to porting the physics portion of the Augie vector processor into Vexx.

My test of any such ported version would be to run my previously published  gravity clock escapements and my walking man simulation models.  Feel free to include these with one of your distributions as examples of some more extreme ways of using the vector processor to simulate real-world items.

Some of the features of these models include exploit convex surface, use of multiple group numbers in an object containing grouped together objects, selective collision control between groups,  pivots,  motors, forced gear ratios between objects,  linkages, simplification by decimation of more complicated shapes.  I have not had the need to simulate any machines so far that contain linear springs or magnets.

I am currently analyzing and modeling the gear trains in a Mr Machine Toy that I purchased Christmas 2019. This will first be modeled using gearotics.  Eventually I'll try to migrate the gear trains to the vector processor as a more realistic version of the walking man simulation.  Due the the complexity of the gear train, I will probably use fixed gear ratios on most of the gears.

It would be nice to be able to model torsional springs such as the hair spring of a watch escapement.

Keep up your amazing support of gearotics, Augie & Vexx.

Bill Michael
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