Dynamics Problem with flexible cable

[kschippy]

I work for a company that manufactures a mechanical cable conveyor. The system works by moving a cable with discs attached through a stainless steel tube.

I am trying to determine the total pull on the system and I'm having some issues with the physics of the elbows. The cable is pulled through a large radius elbow (48in CLR). I'm trying to find the force required to do so. Due to the fact that the discs not the cable rides on the ID of the elbow it makes the standard belt/ pulley equations useless. I know I need something that takes into effect the contact surface area and that the cable is attempting to be pulled straight so it doesn't follow the ID of the tube the entire time. Please help.

Our website is

http://www.cablevey.com

it will show more of how the system works.

 

[potteryshard]

I suspect that this is analagous to the conditions and equations used to calculate wire pulling tensions for electric conductors in conduits. These calculations are based on the coefficient of friction between the cable jacket and the conduit. In your case, I'd imagine that you would substitute the coefficient of friction between the bulk material to be transported and the tube; I'd imagine that the friction of the discs would be insignificant in comparison with the material.

I don't have a reference for these equations handy, but they shouldn't be hard to find.

 

[kschippy]

Thanks for the idea. I've been having a hard time finding some analogous application. I still need to have some help on the non-conveying side of the system. I agree that on the conveying side the the disc pull is negligible with most materials.

 

[chicopee]

Your website shows the system that you described more that of a conveyor. You have the internal friction of the disk and material being transported, the horizontal movement of material and disks,the lift of material and disks. the descent of the empty disks and the internal friction of the drive system.

Mechanical engineering handbooks such as Kent espacially older volumes, dating bak to the '40's have good detailed analysis on conveyors not exactly of the type that you have but at least it should get you in the right direction