[NA] Pulley engineering & use

[Let'sgoflying!]

This involves 1/8” cables and a hangar door.
I will be running this cable through a pulley at about a 110°angle.

Must cables pull away from the pulley mounting bracket, or can I choose to flip it so the cable pushes towards the bracket?
The cable is going to stay in the pulley either way.
Just a matter of engineering the mount, one is easier than the other.
The question refers to the rated strength of the pulley.

 

[SoonerAviator]

I don't think you'd run into a strength issue either way as the bracket should be seeing the load one way or the other. I think the problem with the cable "pushing towards the bracket" would be the instant any slack in tension occurred which might cause the cable to unseat from the channel and then off of the bracket entirely. In the "pulling away from bracket" instance, even if it got slack, the bracket would contain the cable from coming completely out.

Think about a typical riding lawnmower deck. There are some pulleys where the belt tensions toward the bracket (usually idler pulleys), and some that run through the bracket and "pull away".

 

[Sac Arrow]

Strength wise it's fine. What I would worry about is a cantilever force incurred by having the cable slightly off center, or the bracket itself not being completely flush with the surface it rests on. I suspect the bottom is slightly rounded.

Check to see if it wants to roll slightly and if it does, shim the hell out of it.

 

[Mikey52]

And build a cable retention bracket or tab.

 

[SoonerAviator]

Strength wise it's fine. What I would worry about is a cantilever force incurred by having the cable slightly off center, or the bracket itself not being completely flush with the surface it rests on. I suspect the bottom is slightly rounded.

Check to see if it wants to roll slightly and if it does, shim the hell out of it.

Might be worth having a pass or two on a mill to make sure the mating surface is flat/true.

 

[MauleSkinner]

It’s called a “pulley,” not a “pushey.”

 

[Dana]

The only issue you may run into is if the load isn't perfectly centered to the plane of the pulley. In tension mode (cable between the pulley and the bracket) any misalignment caused side loading would tend to straighten out the bracket, but if the cable runs around the outside any misalignment would tend to push the bracket further out of plane, causing it to collapse sideways. Probably not an issue unless the misalignment is significant, but something to consider.