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Three/four sprockets in horizontal line can be run by chain?

  1. May 20, 2016 #1
    Hello people, I have a serious design problem for designing a sprocket-chain system. I want to know that can three sprockets as in picture (in attachment) can be rolled by a chain? The main concern is for middle sprocket it have few teeth above and few teeth in bottom connected to chain. The other two sprockets (left one and right one) have maximum teeth connected with chain (In "C" and "Ɔ" shape as you can see in picture). The right sprocket will be connected to motor shaft (Motor have 16kg torque (Rotational force)). The middle and right sprocket will be connected to load shafts, both will need 8-8kg torque to be rolled. So if there is only two sprocket and chain (which is common in most applications) then there will be no problem to roll two sprocket. But the problem here is that THE MIDDLE SPROCKET. Can this middle sprocket be run well in this three sprocket-chain system as in first pic. The sprocket will need 8kg torque to roll. So can anyone help me out to tell that can this MIDDLE sprocket be run well in this three sprocket-chain system ?? I will be very sad if it wont run. If it wont run can you give any open mind idea to run this kind of system. An added option to answer is that if there are four sprocket in the chain in place of three as in first pic can this four sprocket-chain system will be able to run well ?? Your any opinion and solution will be a lot welcomed. Thanks in advance. :smile:
     

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  2. jcsd
  3. May 20, 2016 #2

    Nidum

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    This is never a good arrangement for a chain drive .

    You would need to use jockey sprockets or jockey rollers to ensure adequate chain engagement around the centre drive sprocket and to stabilise the chain .

    If there is enough space it would be better just to use two sprockets on the centre shaft and a separate chain to each of the outer sprockets .
     
    Last edited: May 20, 2016
  4. May 20, 2016 #3

    berkeman

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    Or maybe go with a triangular arrangement of the 3 sprockets...

    http://unifiedsupply.com/files/5-Triangular-Style-Drive-685x430.jpg
    5-Triangular-Style-Drive-685x430.jpg
     
  5. May 21, 2016 #4
    Thank you very much Nidum you gave actual right solutions for it. You understand the concerns of designing.
    Thank you berkeman for your suggestion but I cant use it in triangular arrangement, as I had told in thread name that it needs to be in horizontal arrangement as in pic I showed.
    By the way friends I found the solution for this problem, I can use tensioners to keep the middle sprocket roll well. Have attached pic and arrangement in attachment. I hope it will work well and bear the load it will get during operation. Any feedback or important things which needs to be considered for using it will be a lot appreciated if you can give. Thank you.
     

    Attached Files:

  6. May 21, 2016 #5

    CWatters

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    I think those guides are really just intended to stop a chain bouncing too much (eg when a vehicle goes over rough ground). I doubt they are meant to be under constant load to ensure a chain is meshed.

    The angle of the teeth will tend to lift the chain out of the teeth. Jockey sprockets may help but they may have to be quite highly sprung loaded.

    Why can't you use two or more chains as they do on tandem bicycles?

    http://www.cyclingabout.com/wp-content/uploads/2013/03/wpid-Photo-27032013-122-PM.jpg
     
  7. May 21, 2016 #6
    Don't you need a certain number of chain-sprocket teeth engagement for your system to work properly, or have you not worked that out yet?
    A chain drive has a slack side and a tension side.
    The tensioner idea has not added extra teeth to the middle sprocket-chain on the tension side.
    The slack side over the sprocket does what?

    With the tensioners as shown, and the chain tension and slack side encountering the middle sprocket, you might end up with some fighting for which length of chain is to drive that middle sprocket. Will you be setting up some disturbing vibrations in the chain and early failure?

    The only way I would use that arrangement is with the chain and sprockets very much overly designed for the application.
     
  8. May 21, 2016 #7

    Nidum

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    The ' correct ' way of doing this uses two jockey wheels to force the chain to wrap around the upper part of the middle sprocket and two more jockey wheels to keep the chain completely out of engagement with the middle sprocket at the bottom .

    This type of arrangement though is really only suitable for low speed / low power drives .

    +1

    @shanky5 - what is the purpose of this drive ?
     
  9. May 21, 2016 #8
    CWatters, 256bits and Nidum you people made me to think that these tensioners might not be able to make the middle sprocket get 7-8 kg torque for rolling the load on its shaft.
    The arrangement I showed you in my previous reply was not exactly I will make, it was just to give you people an idea that how I will use those tensioners. I will keep those tensioners tight/close enough (see attachment) so that it makes the chain to cover as many teeth as possible of middle sprocket from both above and bottom side. That's what I thought might will work. what do you people think this might work ?

    CWatters and Nidum I cant use Tandem cycle design because space is a important concern for designing. Cant use space beside middle sprocket as in tandem cycle. That will be last option to choose if I wont find any other way to make it work.

    256bits yes I have number of teeth of sprocket. My concern is to find a way to make this design work.

    Nidum this design of three horizontal sprocket will be used to roll a shaft connected to middle sprocket. The shaft will need around 7kg torque to roll. The RPM of all sprocket will be 80 RPM. The purpose is to roll only the shaft by this design of three horizontal sprocket. So the only concern is to make this design work in lowest cost :frown::frown::frown:. Thanks in advance for any help .
     

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  10. May 21, 2016 #9

    Nidum

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    The arrangement shown could lock up . Certainly it will not run freely and there is danger of breakages .

    Let's start in a different place . Easiest way of arranging a drive for this type of roller configuration would be to use 5 gear wheels . One on each shaft and two intermediate gears .
     
  11. May 21, 2016 #10
    Thank you very much nidum for your reply. your this reply helped me a lot. I should use these two rollers (check attachment) as tensioners in place of tensioners I showed in my previous replies. These rollers might will not lock it up and danger of breakages might will be removed. check it and reply please I am waiting for your reply...
     

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  12. May 23, 2016 #11

    Nidum

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    How big are the chain wheels and what are the centre to centre distances of the rollers ? Also what type and size of chain ?
     
  13. May 25, 2016 #12
    @Nidum I have attached the rough design of the this system in attachment. The chain wheels (sprocket) are 62.7mm outer diameter. The centre to centre distance of rollers will be around 38mm. The rollers diameter will around 25mm. I have attached size chart for sprockets for your reference if you need more details of sprocket and chain. 03B is the standard for chain and sprocket I will use and I will use 38 teeth sprocket from the chart you can check the chart if you need more detailed sizes of sprocket and chain. So can you tell now will this system work fine ??

    And apart from this can you tell the minimum distance I can keep between two sprocket in this system (see pic in attachment) that will be veryyy usefull information for me. Thanks Nidum waiting for your reply.
     

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