Unique gearbox for weedeaters.

[Garp]

I recently posted details of my custom gearbox for weedeater type engines, I am quite proud of it. I got some great feedback and it started me thinking about building them from home to sell.
would anyone be interested?
It solves all your gearbox problems neatly, I couldn't break the prototype even though I tried, and it's easily adapted to a large variety of motors including electric.
If you have any questions or suggestions put them here...

[SimpleSimon]

Interesting. Give me some details please - gear ratios, final output gear size, suck as that.

[Garp]

It is synched to the pedal speed so when you pedal flat out the motor will be at full revs.
The front sprocket is driven so the gearing is determined by what is behind it.
This one has a 100/1 reduction between the clutch and the crank. Power goes to a seven speed shimano, which has been excellent.
It only has one chain and no extra levers, just a throttle. It's slim too, I only had to extend the pedal shaft a small distance to clear the motor. I don't even notice it till I ride my Giant.
Check my other posts to see it going.

[loquin]

Worm drive gearbox?

Is there a freewheel on the peddles, so that you don't have to peddle when the engine is running?

[Garp]

Yes it freewheels. Everything works fine.

[GearNut]

So it's a dual output, single speed industrial reduction box, most likely originally set up for an electric motor such as a 1hp? (I can't figure out how that would allow the left pedal to stay in synch with the right pedal and still freewheel though.)

[Garp]

Magic, lol.
You'll work it out, I did and I'm a plasterer.

[GearNut]

Ooooh! I get it now!
I need to get plastered before I ponder the inner workings. (A corny joke, don't take it wrong.)

Hmmmmm.......
Freewheeling crank arms, sorta like what is on a shifter kit, on both sides would never stay in synch, but a jackshaft ran through the gearbox and geared internally somehow...... hmmmmmm....

[Garp]

That could work!

[V 35]

I give credit to anyone who can supply power directly to the sprocket, and not use a Rag Joint. Safe Bikes are important. Your pictures don't show enough. I'd like to
see an uninstalled one, and installed one, and a price / shipping cost ?

Good luck, you seem on right track . I also must ask, can the deraileur take the
torque of an Engine ? Extra, clutch side kill button, might make sense, kill mag,
shift, release button.