RE: [CAD_CAM_EDM_DRO] Re: automated "labjack"

Hi Graham,

This must be similar to adding a knee to a mill then?

How about a relatively large round cam (about the size of the table to be
lifted). The SIDE of the cam is what's used. An you have a 3 or 4 "start"
cam, that is, there are 3 or 4 "rises" in the face of the cam.

So it follows that if you affix this cam to the face of an RT (rotary
table), and rotate the table, then 3 or 4 small roller bearing "followers"
will ride UP, carrying your work table. If it's an appropriate size, then a
Sherline CNC RT might fill the bill quite nicely. You'd also need guides to
keep the table to be lifted from rotating.

You could also make a worm gear with a tap, and drive the cam with that.
Single motor. Amateur telescope mounts often use a worm drive made this
way.

You might want to actually make the 3 or 4 cam faces as separate pieces; it
might make it easier to machine them. Just bolt up the stock on the rotary
table (assuming CNC), and combine a Z move with a RT (C) move. You can make
a "cup" first, as the cams only need to track on a narrow cam (the "edge" of
the cup).

(That was a fun mind exercise).

I might just make one. I think it might be a useful accessory for my mills.

Alan KM6VV

> Graham Stabler
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "David G. LeVine"
> <dlevine@...> wrote:
>
> > A simple question: How fast, how often and how
> > much weight need to be handled? If it is a light
> > load, a tiny electric motor with gear reduction
> > and a cam system might be best. Two or four
> > small wires are pretty simple to add to the head
> > cabling. Limit switches would make it 4 wires,
> > mechanical stops and current sensors would work.
> >
> >
>
> Well I have some tygon, if that can be used that would be OK.
>
> I wondered about a small motor, if I do put the auger drive on a
> spline then there is very little weight to move, I'm sure even a tiny
> rc servo could handle it.
>
> Graham