Chains and Sprockets in Assemblies

Van70 · May 10, 2004

I need some help from some advanced Solidwork users that are familiar with power transmission devices (chains and sprockets, pulleys, and drives, etc).

I need to if it is possible to mate a chain to a sprocket and allow it to "function" when I move the parts. I don't care if the sprocket turns. I just want to show the chain "engaged" at all times.

Scenrio:

I am using a chain and two sprocket for sycronization of a hydraulic lifting device.

I have a length of #100 chain (1.25" pitch). Each end of the chain is anchored. In other words, the chain is *not* circular like a bike chain. Two sprockets run up and down this length of chain as the device is lifted and lowered. The chain "S's" through the two sprockets.

How would you mate the chain to the sprockets so that the chain is always mated to the sprocket no matter where the sprocket is located. In other words, As I move the parts, I want the chain to be wrapped (engaged) with the sprockets.

I think the best way to do it is to draw a flexible center line in the CHAIN assembly (yes, the chain is an assembly of flexible links). Then, Mate that chain center ine coincident to a circular line (representing the pitch line) on the sprocket. Could you use advice here.

SBaugh · May 10, 2004

Not sure if you can get the chain to move with the sprockets, without first trying it myself. I can't think of a way to do it off the top of my head, but I know you could possibly set up 2 sprockets to work together. See Gear and pulley mates.

Regards,

Scott Baugh, CSWP [borg2]

http://www.3dvisiontech.com

http://www.scottjbaugh.com

faq731-376

Dennyd · May 10, 2004

Van70,

You might be able to create a sketch in the assembly that represents the centerline path of the chain and wraps appropriatly around the sprockets with suitable constraints. You can use an equation to control the length of the straight line segments to maintain a constant overall length. As you move one sprocket the file will have to regenerate to recompute this equation and update the sketch and subsequent mated postion of the other sprocket. You could also create an equation that relates the position of one sprocket with respect to the other, but this sketch method allows moving either sprocket and the other following.

If this sketch can be converted to a spline, perhaps in another assembly sketch then I think you can mate the chain segments' pin axes to this spline line and they will update their position accordingly.

This step frame motion might give you what you have to have, even though it might not give you what you want (fluid motion of these components). This is a good problem. Keep us informed of what you eventually settle on.

- - -Dennyd