Frustration! No one makes a sprocket that can be engaged and disengaged?

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I have been searching for 2 days now and cant find a sprocket that can be engaged and disengaged, Very frustrating! The plan,....(sigh) is to go from the engine shaft with a manual TQ then to a solid shaft with multiple sprockets. Lets say we have 4 sprockets on the second shaft. The first sprocket solid, the next 3 sprockets engage able and disengage able. Those sprockets would go to gradually smaller sprockets on shaft 3. Shaft 3 would have 4 sprockets, the 4th would be connected to rear axle. Wallah easy transmission. This is how it would work engage clutch and sprocket 2 1st gear, disengage clutch and 2nd sprocket, engage 3rd sprocket then clutch rinse repeat. I know I am not crazy, in my researching I discovered that back in the day the french made a motorcycle like this. 2 speed 2 chain 1st drive sprocket would ratchet then second would be engaged and the low gear could be overturned due to ratcheting of 1st sprocket.
 
chancer

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Dont mind them ^they are just Grumpy old men.
You lost me but here are a couple of links to different things along the lines of what I think you are getting at.
This is not 2 speed but he uses a 1 way bearing in the clutch. Something you may need:
http://www.diygokarts.com/vb/showthread.php?t=32273&highlight=speed
This guy is trying to make a 2 speed Clutch:
http://www.diygokarts.com/vb/showthread.php?t=32529&highlight=speed
and this IS a 2 speed clutch on a mini bike:
http://www.diygokarts.com/vb/showthread.php?t=28502

None are exaclty what you want but some basic ideas and parts for a multi speed go kart tranny.
Good luck though, many have tried this, never seen one finished, at least not here!
 
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mckutzy

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Well I think there are already some types of transmissions like what your describing...
Referring to my thread about quite similar topic...
http://www.diygokarts.com/vb/showthread.php?t=24992

or.....

A series of electric clutches that will engage the selected "gear set" on the lay shaft....But that requires a significant amount of power, to power the engagement.

I have spent quite the amount of time on pondering/researching/studying this and other transmission designs....... Not much comes up......
 
FreeRunner15

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If only someone would invent a series of sprockets and springs . One spring with a hook of some sort attached to it so it engages to the next sprocket somehow at a higher RPM due to centrifugal force.
Gear 1 activates at 1200rpm until the mild soft spring with a hook hooks onto or into..gar2
Gear two: which has a mild stiff spring until that hook grabs onto or into..gear3
Gear3: with its stiff spring it goes to..
then Gear 4:most likely all you need on a kart unless you want to peel tires everywhere you go .all custom shift points. shift points depend on the stiffness of each spring attached to each sprocket.

invent that for me. i'll test it for you too.:thumbsup:
 
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A simplifiied version of what you are after would be a 2 speed manually shiftable jackshaft...

the jackshaft would have three sprockets on it. One sprocket would be keyed to the shaft and connected to the engine's clutch via chain.

The other two sprockets on the jackshaft would not be keyed to the shaft, instead they would be supported by ball bearings so they can freely spin. These two sprockets would be connected via chain to two sprockets on the rear axle. Different size sprocket combinations would offer different gear ratios.

Also on the jackshaft and positioned between the two freewheeling sprockets would be a collar that is keyed to the jackshaft. This collar would be able to slide axially back and forth. On each end of the collar would be 'dogs' that would engage identical dogs machined on the inside face of each sprocket.

A motorcycle shift lever or even a bicycle shifter could be used to shift the collar and engage one of the two sprockets at a time. Or neither sprocket if you wanted to be in neutral.

No way to avoid making those custom sprockets and shift collar.

Of course the type of clutch used on the engine would be important.
 
itsid

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You can find one way hubs for sprockets on industrial mechanic shelfs.
a single piece is rather expensive I'm afraid, so such 4speed can easily pull something like500bucks off your pockets;
just to achieve proper idling behaviour (no shifting yet)

also a much smaller package can be achieved for much smaller budged by salvaging an motorcycle gearbox's internals (manual clutch included, shifting fork and gears for sure.. six-speed quite common ;))
it'd be even cheaper to buy a motorcycle engine.. and that's why it'd be hard to find off the shelf parts (at reasonable prices)

many automation processes use parts that might fit or can be adapted to gokart use, but those come at a price..

'sid
 
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mckutzy

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That or a big twin Harley type... Devorced transmission..
A transmission, basically of any type... Is going to be money and time making it... Without proper tool and equipment. Not to mention the knowlage to assemble the package...
 
chancer

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Hey ML! :kewlsmiley: You are gonna need a Pic with a 3rd "Grumpy old man" Now that Machinist@large is weighing in.
but what do I know I am just a young punk!:roflol:
 
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DDOWNS46 nailed it! Exactly what i am trying to do, Only difference is I would use extra collars to have even more gears on the jack shaft. Oh and about the motorcycle engine, they are at least 300- 400 shipped. Shipping kills you. I figured my idea might be cheaper. But that doesn't matter now I just nailed a huge score today I am going to have to put it in new thread!
 
bob58o

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At work so no time to read it all. Been thinking about how DD put one way bearing in his clutch.
Not for same reason, but a possibility maybe?
 
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