The Art of Ratios

This is a picture of the drive train in our living room that we use to raise the roof when it gets too hot in the summer........ok, nobodys buying that. This is a work of art, created by my buddy the mandolin builder. It doesn't do anything except annoy my mother when she's visiting. Assuming the largest gear to be "D", and the worm gear to be "A", calculate the following ratios.

1. A : B
2. A : C
3. A : D

It's actually very easy, so none of this waiting for GT to figure it out and then just agreeing with him!

 

ok, i wont wait for GT,,,

I'll agree with him NOW

 

Pitch on the worm gear looks to be one tooth per revolution, so

A:B = 1:13
A:C = 1:17
A = 1:28

The odd intermediate gears don't really confuse things any, as each gear moves one tooth for each rotation of the worm gear.

 

my guess:

1:13
1:16
1:29

ok... well, i'm probably wrong, so i'm going to agree with gt as well

 

um . .no?

cool art
da^^n cool

 

Sheesh! I can't even count gear teeth before coffee.

B has 12 teeth, and C has 15, or am I still cross-eyed? So

A:B = 1:12
A:C = 1:15
A: D = 1:28

 

assuming that all cogs where complete
I don't like to disagree with GT
so I just left it as is

but being that two (A and D) are incomplete gears

A: can only move .25 a rotation correct?

but lets assume that A is complete and D is as is?
so
A moves around fully once
moving B 3 teeth
moving c 2 teeth
moving D 1 tooth

hmmm. . .?

 

A seems to be the question mark. Draw a straight line across from one of the worm gear's "teeth", and you go from one tooth to one cavity, which would represent half of one rotation of the gear. This implies that one full revolution would move one full tooth, so one tooth per revolution.

 

Glad to see you changed your original calculations GT. I had to recount the teeth myself to make sure I was correct. I held a straight edge across the diameter of gear D. so I figure if the entire gear existed then it would have thirty teeth. Looking at it on the screen, It's hard to tell how many teeth it would have. The worm gear has only one tooth therefore the A : D ratio is 30:1. The idler gears in between have no effect on the final ratio, and in this case don't even serve to change final direction. They're only there to look good.http://forums.majorgeeks.com/images/icons/icon7.gif

 

LOL. Whatever the actual count on D, we're working in the same direction.