"Gunner" wrote in message
...
On Mon, 13 Feb 2006 10:59:32 -0400, "jtaylor"
wrote:


"Grant Erwin" wrote in message
...
jtaylor wrote:

In my head I have a kind of picture how a rotary table might be made.

You have a base, with a central pivot (could be bored for a taper).
Around
the pivot is a gear & the table, driven by a worm.

Some of these tables are advertised to have a method by which the
table
can
be decoupled from the gear, to allow quick rotation without turning
the
worm. I have been turning this picture around and around in my head
and
cannot figure out how they do this.

Someone tell me or point to a drawing, please...



The worm is mounted on a shaft which is cammed so that rotating the
shaft
causes
the worm's center to move away from the gear's center, effectively
disengaging
it. This is a very desirable feature on RTs and in my opinion a must
have.

GWE

Aha.

There'd have to be some method of adjusting the position of the worm in
the
cam (or the bearing surfaces of the worm) then.

Ayup..this also allows you to take out any backlash.


Um, only some - that between the worm and gear teeth. The worm might also
shift axially; need something to handle that as well.