Re: ATM Mel's System

[cshaw@ghg.net (Charles W. Shaw)]

At 5:02 PM 5/27/97, Michael P Lindner wrote:

>I've had little to no luck finding an inexpensive source for a speed
>reducer.  I was wondering what you and others did.  Feel free to post this
>(or your reply) to the ATM list if you feel there's enough interest.
>


Michael,

I purchased two 4" byers gears and made hubs and clutches for them.  They
give a 359:1 gear reduction and work REALLY well....  However, after I went
to all that machine shop work trouble, I think a much better and MUCH
cheaper solution is a drive roller reduction.  To explain:    The drive
roller that the altitude sector rides on has a larger disk attached to it
where my gear attaches.  The motor has a small shaft (1/4") that is pressed
against the disk in the same fashion the altitude sector rides on the drive
roller on the opposite end of the shaft from the disk.

A 24" dia sector and a 3/4" drive roller is a 36:1 drive reduction.   A
1/4" shaft on the motor, running against a 3" dia disk (that turns the
drive roller) is a 12:1 reduction.   That results in a system reduction
from the motor to the altitude axis of 36x12= 432:1   Thats a very good
speed reduction!!!!!


Advantages:  NO periodic error!  NO tedious gear mesh adjustments!  VERY
cheap (even if you have to go to a commercial machine shop to get it
made...But I would contact Andy Saulietis at andydtg@phoenix.net to see
what he would charge also)

Con's:   Potential source for slippage, but a good adjustment mechanism
will prevent that.......   Probably needs to be metal to withstand the
pressure needed to avoid slippage and be accurate.....


Chuck


Chuck Shaw
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