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Tom Gardner[_2_]

"Gunner" wrote in message
...
On Thu, 26 Jun 2008 16:13:43 -0400, "Tom Gardner"
wrote:

"Gunner" wrote in message
. ..
On Thu, 26 Jun 2008 11:11:20 -0400, "Tom Gardner"
wrote:

"Gunner" wrote in message
m...
On Wed, 25 Jun 2008 22:38:19 -0700 (PDT), wrote:

On Jun 25, 10:37 pm, "Tom Gardner"
wrote:
I want to turn a 4" OD x 3/8" thick gear 80 to 110 degrees in 100 ms.
I'm
thinking of a 4" stroke by 1-1/4" bore air cylinder attached to a rack
gear
that
would engage the round gear. No, I won't do it with a servo! I'm
thinking a
1/2" round rack gear in a tube with Thomson linear bearings and a
scallop
cut in
the middle of the tube to expose teeth to the round gear. This seems
simple
and
cheap. In fact, it's so simple it would seem that it should be an
off-the-shelf
item! I just assume it would be easier to do with round rack than
square
rack.
Is this available or did I invent a new wheel?

The gear would just spin back and forth and the air cylinder/rack will
have
an
adjustable stop to get my 80 to 100 degrees rotation. The round gear
will
have
a one-way clutch installed because I only want the one direction of
shaft
rotation. The shaft will power a wire feed mechanism to feed 3" to
3-1/4" of
wire.

They make pneumatic rotary actuators to do exactly what you want, turn
a shaft through a partial revolution and back. Kind of like a super-
sized version of the old vacuum windshield wiper motor, uses a vane in
a chamber driven by pressure, not vacuum. Might explain why you don't
see a geared actuator like you describe. Unless you've got a lot of
scrap parts laying around, might be the cheaper way to go!

Stan

I thought I sent one of those to Tom already?

Gunner

I didn't see it, I'd be interested in purchasing one if you still have
one!

Geeze....email me your freight info again..Since Ive been on a kick to
trash stuff...Im down to the pneumatics section in the stacks O stuff

Tell you what...Ill email you pictures of the stuff..and if you
want..Ill ship you the entire lot. Might be several thousand pounds
of cylinders, etc etc. All NOS, ablit some has some surface rust in
non critcal places

Free..you pay for the shipping

Gunner

EEEEEEEEEEEHHHHHHHAAAAAAWWWWWWW!

If you are interested, call me. You should have the number

Gunner

I will call! I can't use a lot of that stuff but pneumatics and linear stuff
always comes in handy. I can't believe you aren't listing it all on eBay. For
every ass, there's a seat.