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Dr Joe's Chain Path Visualizer

Joe Johnson

By: Joe Johnson
New: 01-07-2005 02:07 PM
Updated: 01-07-2005 02:07 PM
Total downloads: 929 times


This is a tool I use to get my chain adjuster travels right and to give my "gut" a chance to "see" the chain path before I commit to it in metal (I like to judge the amount of chain wrap around a sprocket visually).

It is not a perfect tool. It does not have any way to en...

This is a tool I use to get my chain adjuster travels right and to give my "gut" a chance to "see" the chain path before I commit to it in metal (I like to judge the amount of chain wrap around a sprocket visually).

It is not a perfect tool. It does not have any way to enter a slider for example. Also, the cell that shows "tight chain," "loose chain," and 'very loose chain" should be taken with a grain of salt (it should have in it something comparing the lengths of the chain runs to the amount of chain movement you want to accept for example). But... ... an imperfect tool is sometimes better than no tool, provided you realize the tool's limitation.

Here is how I use it most often:
#1 I layout my chain path (counter clockwise order around the chain)
#2 I move my "idler" up and down (or left and right) the amount I plan to build in to my adjuster so that I can tell if I can actually tighten a the chain.

Alternatively, I use it to see if I can swap sprockets and still tighten my chain with the different ratio (this is a non-obvious calculation at times).

Finally, I hope this will give some of you an introduction to "GoalSeek" in Excel, which is an extremely powerful tool that very few folks utilize. I use this sometimes to position my sprocket to give me "exactly" the right amount of length to have a EVEN number of pitches. Anyone who has had as much trouble with "Half links" (a.k.a. "Offset Links") as I have will appreciate the beauty of having an EVEN number of pitches in your chain length.

Hope you find the tool useful

Joe J.

Attached Files

  • xls Dr Joe's Chain Path Visualizer

    1105128447drjoeschainvisualizerrev1_0.xls

    downloaddownload file

    uploaded: 01-07-2005 02:07 PM
    filetype: xls
    filesize: 271kb
    downloads: 927



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01-19-2005 10:19 AM

Joe Johnson


Unread Anybody using this thing?

Just curious if anyone is actually using this spreadsheet/visualizer.

A lot of folks have downloaded it, but I have yet to receive any feedback one way or the other.

Teams should be getting to the point where they are actually laying out chain paths. I hope that this tool helps folks think about routing and in particular think about tensioning systems for you chain (and, most importantly, making sure you have enough travel in your tensioner).

As always, Feedback is welcome.

Joe J.



01-19-2005 11:38 AM

JVN


Unread Re: Anybody using this thing?

Quote:
Originally Posted by Joe Johnson
A lot of folks have downloaded it, but I have yet to receive any feedback one way or the other.
Joe,
Just noticed it this morning when you posted. (Things have been hectic, and whitepaper reading has fallen through the cracks.) I've been wanting something like this recently, and so I downloaded it and rushed to try it out.

I modeled some of 229's drive chain, and it worked out GREAT for me.
This is an incredible tool, that I will no doubt use like crazy.

The functionality is excellent, but my ONLY criticism is the user interface takes a second to figure out. I managed ok, but newbie designers may have issues. (Though I guess one could argue - if I can do it, anyone can )
Perhaps (whenever you get a spare moment - sometime in 2010) you could do a revamp which makes it easier to use for rookies. Until then, I'm sure we'll all manage just fine.

This is definitely a great tool, I urge all mechanical designers to check it out.

Attached below is a pic of one of 229's drive chains. Joe's sheet helped me gain new insight into my tensioning system (as he promised it would).

Kudos,
John



01-19-2005 01:20 PM

Swan217


Unread Re: Anybody using this thing?

Brilliant visualizer, Dr. Joe! Gone are the days of randomly estimating chain lengths and tensioning it at the last second. A must-have tool for the "chain gangs" out there.



01-19-2005 01:49 PM

ajlapp


Unread Re: White Paper Discuss: Dr Joe's Chain Path Visualizer

i used it to lay out simple two sprocket setups.....just using the goal seek to optimize the center distance. dennis is using it for his drivetrain calcs and so far things look great.

would it be possible to add a field which display the center distance between sprockets? i don't mind using the pythagorean but a field which did it for you would be swell.



01-19-2005 01:57 PM

Rocketboy


Unread Re: White Paper Discuss: Dr Joe's Chain Path Visualizer

I'll have to get my team in-touch with this application. Nice work



01-19-2005 02:03 PM

Joe Johnson


Unread Re: White Paper Discuss: Dr Joe's Chain Path Visualizer

Quote:
Originally Posted by ajlapp
i used it to lay out simple two sprocket setups.....just using the goal seek to optimize the center distance. dennis is using it for his drivetrain calcs and so far things look great.

would it be possible to add a field which display the center distance between sprockets? i don't mind using the pythagorean but a field which did it for you would be swell.
Good idea. I will think about it and see what makes sense. I am thinking that I could add a column that shows the distance to the sprockets before and after the current sprocket. Should be a piece of cake.

Joe J.



01-19-2005 02:24 PM

Swampdude


Unread Re: White Paper Discuss: Dr Joe's Chain Path Visualizer

Nifty tool. It should probably be noted for the layman that one goal of chain and sprockets is to achieve 180 degrees of engagement per sprocket. But when you can't, I'm curious if you could add to this, such that you key in the motor torques and assume stall. Then let the spreadsheet estimate the needed amount of tooth engagement at each sprocket (depending on radius etc). Maybe you could indicate which is the drive. Now thats the deluxe model!

Also I noticed on the top of the page you're saying to only edit the green fields. But you need to "green" the "Nspr" (number of sprockets) field in case we don't have a 6 sprocket setup.

Also users note:
make sure to zero out the extra fields beyond the number of sprockets needed



01-19-2005 02:38 PM

Joe Johnson


Unread Re: White Paper Discuss: Dr Joe's Chain Path Visualizer

Quote:
Originally Posted by Swampdude

Also I noticed on the top of the page you're saying to only edit the green fields. But you need to "green" the "Nspr" (number of sprockets) field in case we don't have a 6 sprocket setup.

Also users note:
make sure to zero out the extra fields beyond the number of sprockets needed
The spreadsheet calculates "Nspr" based on the number of spockets you enter (or it WOULD if you don't enter a number in by hand

You are correct however in that the tool has some ease of use issues.

Joe J.

P.S. I know of no rule of thumb that say the goal is to wrap 180 around each sprocket. I have no objections to 180 degrees of wrap, but many times I live with much less. I typically am more concerned with the number of teeth engaged than I am the wrap angle getting to 180. For what it is worth...



11-24-2008 05:05 PM

AdamHeard


Unread Re: White Paper Discuss: Dr Joe's Chain Path Visualizer

Not sure what magazine this is, but the chainpath visualizer is definitely in it.

After so many uses, I'd recognize it anywhere

http://www.flickr.com/photos/ken_bra...91/3005447427/



11-24-2008 05:31 PM

Madison


Unread Re: White Paper Discuss: Dr Joe's Chain Path Visualizer

Quote:
Originally Posted by AdamHeard View Post
Not sure what magazine this is, but the chainpath visualizer is definitely in it.

After so many uses, I'd recognize it anywhere

http://www.flickr.com/photos/ken_bra...91/3005447427/
Based upon the previous page (photo), it is Servo magazine's Nov. 2008 issue.



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