The Perfect Chain

uploaded by alfredix 4 months ago

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When I played a bit with my Gepard ( http://www.3dvia.com/alfredix/models/6A05906072445668 ) yesterday I somehow had to fix the issue with the tracks. If you look closely to the Gepard, you will find the chain links are not perfectly aligned to each other. They are “loose”, especially around curves at the wheels.
the reason is, that the chain links were patterned along a path (or curve). Now the CAD system (as far as I know NO CAD system) knows, that I want to make a chain, so it take the “curve length” instead of the pitch of a chain link. It is simple Trigonometry to find out that the pitch is shorter than the “real curve length of that sector”. In reality a Chain is always a Polygon with n elements. Each element has a the length of the pitch, which is the distance between 2 elements.
the challenge was not the straight part, but more the end of each curve when it goes “tangentail” to the next straight part.
Finally the real challenge is to arranage all links, so the last link goes exactly in the first link.
this is what I call a perfect chain. And here it is. I must admit, that it is a special case, where the chain is symetrical, but it works. :)
For those of you who have tried before to make a chain, knows what I am talking about. For the other, go and try. First it is fun but it gets frustrating soon, if at the end it doesn’t fit.
I posted some sketches in my web album to show you the geometry behind the placement.
http://picasaweb.google.com/alfredeix/020Common?feat=directlink
Trust me, it is not so easy as it looks, if it should be “perfect”
And for those of you who don’t know, why a perfect Chain is needed at all. Let me tell you I am a Mechanical Engineer and my creativity goes beyond Screw and nuts” (Best regards to XQH_XXX at this point :) )

When I played a bit with my Gepard ( http://www.3dvia.com/alfredix/models/6A05906072445668 ) yesterday I somehow had to fix the issue with the tracks. If you look closely to the Gepard, you will find the chain links are not perfectly aligned to each other. They are "loose", especially around curves at the wheels.
the reason is, that the chain links were patterned along a path (or curve). Now the CAD system (as far as I know NO CAD system) knows, that I want to make a chain, so it take the "curve length" instead of the pitch of a chain link. It is simple Trigonometry to find out that the pitch is shorter than the "real curve length of that sector". In reality a Chain is always a Polygon with n elements. Each element has a the length of the pitch, which is the distance between 2 elements.
the challenge was not the straight part, but more the end of each curve when it goes "tangentail" to the next straight part.
Finally the real challenge is to arranage all links, so the last link goes exactly in the first link.
this is what I call a perfect chain. And here it is. I must admit, that it is a special case, where the chain is symetrical, but it works. :)
For those of you who have tried before to make a chain, knows what I am talking about. For the other, go and try. First it is fun but it gets frustrating soon, if at the end it doesn't fit.
I posted some sketches in my web album to show you the geometry behind the placement. 
http://picasaweb.google.com/alfredeix/020Common?feat=directlink 
Trust me, it is not so easy as it looks, if it should be "perfect"
And for those of you who don't know, why a perfect Chain is needed at all. Let me tell you I am a Mechanical Engineer and my creativity goes beyond Screw and nuts" (Best regards to XQH_XXX at this point :) )