Re: Auto tool changers

Guys,

Maybe you've already covered this......

Emco-Maier, in their small production lathes, used a small DC gear
motor to index the turret. It moves past a position marker and
spring loaded pawl (audible), position is overrun then the motor
backs up bringing the turret tight against the pawl. After a few
seconds the current is reduced on the motor.

These machines have a rear mounted turret, normal turning is done in
M04 direction. Coarse pitch right hand threading (upside down tool,
M03) is a slight problem, even with the position holding of the motor
the turret will rotate very slightly with heavy cuts. Because of
this, 1"-8tpi takes an endless number of passes.

Doug

--- In CAD_CAM_EDM_DRO@y..., "ballendo" <ballendo@y...> wrote:
> Drew,John,
>
> Don't forget the worm drive! Not likely to "back drive". So the
> stepper just needs to hold it's position. And as my previous post
> says, in "normal" use, the pawl will/should take the load.
>
> Hope this helps.
>
> Ballendo
>
> --- In CAD_CAM_EDM_DRO@y..., "John H." <johnhe-uk@s...> wrote:
> > That's what I want to know as well. And also, what holds the tool
> in place?
> > I mean, why doesn't it wander towards the next ratchet when force
> is put on
> > the tool? Is it because the force on the tool in CCW is pushing
> down and
> > trying to force the stop over a wall? If that's so then this sort
> of changer
> > wouldn't work in CW would it?
> >
> > Regards,
> > The Question Master (John H.)
> >
> > > I'm curious how one would prevent the stepper from continously
> > > pushing back on the "stop" too hard and/or for too long.
> > >
> > > Drew