Design of Twisted Chain

Hey people,
I want some help in building a twisted chain drive for 90 degree change in transmission of power. My one sprocket is in Vertical plane and another is in horizontal plane. What should be my optimum center to center distance between the two sprockets ?

My sprocket specs (simple bicycle sprockets and chains) are:-

Vertical sprocket :- Pitch circle diam- 17.6 cm, 48 tooth
Horizontal Sprocket :- Pitch circle diam- 5.5 cm cm, 16 tooth

The ratio i want to get is 3:1.

Please help me with the optimum center to center distance calculations !!
thanks in advance !!

 

You are about 3.1 : 1

The distance between gear wheels is not critical. Make it what works best for your configuration.

Too close obviously wont work. Experiment a little and see.

You can't go from a vertical gear to a horizontal.

Do you have a picture you can post?

 

he means twisted - as the the axis of the sprockets are 90 degrees off.

okaashay you should read posts on the pedal powered boat. Its a big thread but search in it. There is some coverage of the topic.

 

@Submarine Tom,



I have already done a bit of experimentation and made a working chain drive. But it naturally falls off a lot of times. So I wanted to know if there is any standard technique or formula by which you can determine the optimum centre to centre distance of a twisted chain in order to ensure smooth running and reduce instances of Chain falling off.

 

Kerosene: I know what twisted chain means.

Okaakshay: Well I never saw that one coming, good for you. I wasn't envisioning that orientation of the driven gear. Are you making a hovercraft?

 

@Submarine Tom,

Yes. I made a Hovercraft. A pedal powered one. For that I needed to transmit pedal force to a lift fan which is a different plane as seen in the photo. I found out that such twisted chains are used in boats. So I wanted to see if I could get any help in refining my drive and making it even more effficient.

 

Not that I know of. Sorry, not much experience there but from what I recall, they tend to have a high failure rate as well as being problematic. I would think if you had a greater distance between the two gears and employed a tensioner it may work better.

Are there no other options applicable to your set-up?

 

FWIW I saw a guy using a ~ 2 cm wide toothed belt on a home built pedal boat..the sprockets were perhaps 60 cm apart.

 

Have you tried idlers or shoes to contain the chain?

 

A pedal hovercraft is not likely to lift. Have you calculated the power to weight ratio?

 

You should make a chain guide system similar to an MRP Word Cup
It is a system with two plates on each side of the sprocket and a guide wheel on the incoming end of the chain

THis is what they look like
http://leviplur.info/mrp-system-2-world-cup-chainguide.asp

 

A simple "V"belt will pass 10 HP with reaSONABLE EFFICIENCY AND NO LUBE REQUIREMENTS.

Why chain?

FF