Chain and 45 degree brackets

Hase anyone used chain with one sprocket on one side of the 45 degree bend and one on the other side. I am trying to connect the center of the top flat bar to the axles on the wheels with chain. I would like to use gears, but they wont work around the bend.

[ATTACH]7487[/ATTACH]

Is there a way to connect them with chain without some sort of spring loaded idler?

There will be an axle in the center as well. I just have not added it yet.

Thanks!
bogie2.jpg

What exactly is this for?

What do you mean by “they won’t work?”
If you mean the gears aren’t the right size, maybe you can do some Kyle style lathing on some large gears to make smaller ones that fit.

Okay now what you could do is use 3 12 tooth gears on your top channel with the middle one being input from the motor. Then you should be able to use 2 6 tooth sprockets to go to the wheels. And I am assuming you are also gonna want to speed it up so go from 6 tooth to 18 tooth on the wheels to get 1:3. About the same speed as 1:2 on 4" wheels

This would completely eliminate the need for an idler.

A 6-tooth sprocket powering an 18-tooth sprocket is a 3:1 torque ratio.

To OP, using a tensioner of some kind, like an axle with nylock spacers on it, should allow you to tension the chain properly around the bend. We have found that chain links don’t line up perfectly with the holes on straight metal as it is, so no matter what you do with chain, it will take some playing around with sprocket placement or the placement of a tensioner to get your chain at the perfect tension (not too tight, not too loose, just right!).

wow not totally thinking when I posted that :eek:

One of our teams - 81G - had this kind of set up this past year but used mechanums on the ends. They did not have an idler but I can’t remember the exact motor placement. I do know it took a bit of taking apart to replace a broken motor though - so be careful.

They ended up cutting and bending the c-channel to align things rather than use the 45 degree gussets. Not sure if it was due to the chain alignment or not. (Sorry no pictures available)

However, if you do stay with the 45 degree gussets, it is much stronger when you place the gussets on both sides of the C-channel side (use total of 4 per c-channel joint).

Is this the entire robot or a front suspension that is spring loaded to stay on the floor?

It is a bogy style drive idea that I have. It is just part of the chassis not the whole thing. There would be a total of 4 of these on the drive. There would be 2 per side. My problem with the gears is just that they don’t mesh like they should. I will post a picture of the gears when I get back home tonight. Thanks for the insight about doubling up the gussets.
I did some math and there will have to be some form of idler or something because the length of the other sides of the triangle are not divisible by .5 so not totally compatible, but this may work to may advantage if I use chain by making it tighter.

Here is the pictures of the problem. It may be better if I bend the c channel as someone suggested above.

Here is an overall view.
[ATTACH]7491[/ATTACH]

Here is the zoomed in view of the gears.
[ATTACH]7490[/ATTACH]

I’m going to try and test it with chain wen i get to the lab tomorrow. I will keep you guys posted.:slight_smile:
gears_problem_up_close.jpg
bogie_gear_problem_front.jpg

Here’s what I quickly put together for a sprocket and chain solution:

The advantage with this method is that there is a very minimal amount of gearing hanging down below the metal (just a small bit of the 6-tooth sprocket in the middle on the driving shaft).

~Jordan

Quickly? That would have taken us hours :frowning:

Man, I thought we were the only ones planning on trying out a drive of this exact style! Very cool!

On each “bogie” of our drive system, we are using a chain wrap instead of gears to keep the point of rotation level with the center of both wheels(With gears, the bottom would hang down too low and catch on the bump). We have tested with both gears and sprocket/chain, and the S/C seemed to be smoother and we did not have to worry about meshing issues. Looks great!

Jordan i will look at that when i get home( it won’t load at school). I’m glad to hear that someone else is planing to use something similar!

…especially when that someone will be competing against you :slight_smile:

Jordan; how long did it take you to CAD that?

What are you implying, senor Jesse?

About 30 minutes or so. Using iMates sped up the process, but once I finish the 2014 library, it should be even easier.

~Jordan

Jordan it looks great. That is almost exactly what i came up with today at school when i was playing with some parts. Looking forward to the 2014 library Jordan.

Definitely accomplished minimal excess. However, it looks like there’s going to be a lot of friction from the chainwrap. No center sprocket maybe?

Building off of that though. I think you can use the 12 tooth sprockets on the wheels and power another 12 tooth sprocket on top loop of the chain wrap rather than the bottom 6 tooth sprockets instead. Also, i think you can then use spacers and locknuts to make rollers to pull up the bottom chain and maintain the same hang. I heard that smaller sprockets have bigger issues with chain slip so adding a larger sprocket may fix future issues. Also, power fluctuations should decrease cause the angle of the sprocket will be less significant. And chain can handle more resistance. With the current distribution, the drivetrain can only handle 100 inch pounds of torque because of the .5 radius of the 6 tooth gears.

I was referring to Team 5003’s post :slight_smile: I won’t be using that kind of drive if I don’t have to :wink:

I agree. The CAD was based on the original poster’s request that the power source be where that center 6-tooth sprocket is located.