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### Author Topic: Roller expension mechanism  (Read 1445 times)

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#### dsesmg

• Robot Overlord
• Posts: 128
##### Roller expension mechanism
« on: January 06, 2010, 06:25:54 PM »
Hi, I am trying to make a conveyor that has a roller expension mechanism.
Please take a look at this drawing.
http:[email protected]/4251882419/#sizes/o/
As the drawing shows, you can imagin two supporting beam on each side of rollers as rollers will need to be fixed or assembled to something. I don't know where do they need to be attached for the expension mechanism. But anyway, I need those rollers to be gradually expended as they rotate just like a conveyor and I also need each individual roller to be spined as it moves. How can I possibly do this?

#### dsesmg

• Robot Overlord
• Posts: 128
##### Re: Roller expansion mechanism
« Reply #1 on: January 06, 2010, 08:03:43 PM »
I am sorry. I spelled it wrong. Expand is correct.
I am wondering how the pitch of those rollers could be expanded while the individual rollers spin during the rotation of the conveyor.
I am thinking the length of the conveyor would be 2m long. I am not trying to expand the length of the conveyor. I am trying to gradually expand the pitch of rollers.
The minimum expand pitch on the conveyor(the begining point of the expend mechanism) is 10mm and the maximum expand pitch is 150mm.
I made up a drawing for your reference.
http://www.flickr.com/photos/4627940...03031/sizes/o/
The viewing perspective is from the top of the conveyor.
Thank you for taking your time to answer my question.
I am an engineer wannabe. Please teach me.

#### nottoooily

• Full Member
• Posts: 91
##### Re: Roller expension mechanism
« Reply #2 on: January 12, 2010, 01:58:53 AM »
There'd be lots of really complicated ways to achieve that. Why do you need their spacing changing? Do they all have to move together? Are all the rollers driven for their rotation?

You could join each bearing to the next with a spring. Make each spring slightly softer from right to left. Then when you move the right-most roller, all the others follow but keep their spacings proportional.

#### Soeren

• Supreme Robot
• Posts: 4,672
• Mind Reading: 0.0
##### Re: Roller expansion mechanism
« Reply #3 on: January 16, 2010, 10:47:14 PM »
Hi,

The minimum expand pitch on the conveyor(the begining point of the expend mechanism) is 10mm and the maximum expand pitch is 150mm.
1500% expansion is quite a stretch!
If it's for your persimmon sorter... Are you sure you need that? (I see so many people overdo their demands out of either ignorance or a sort of let's-have-it-all attitude and that breaks many an otherwise good project).

If you'd make do with an expansion of say 250% to 300% it gets more attainable, but the way I imagine it done, it takes 4 ball bearings each "roller". (I assume they're not really rollers, but rather just rods?)
So multiply the number of rods used by 4 and it get's to be quite a lot of ball bearings... Is your project worth that much?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?