Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft to
rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is meshed
into the first gear with pressure from another air cylinder. Wire is fed
between the gears in a grove cut in the face of each gear. The idea is to
feed wire 3" per stroke.

Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.
I've considered lightening the gears by drilling a bunch of holes. Also, a
drag brake on one or both gears with screws pressing brass pucks against it.
Another idea is an air limit switch that is struck at the end of the stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in time?
Would I be better off with an electric switch and valve? I might have to
lighten the gears, brake them and switch off the air clamp The feed has to
take place in 300ms.

Buerste writes:

Would I be better off with an electric switch and valve?

The flaw of your design is that you do not control acceleration and
deceleration, which not only is brutal, but prohibits precision control
such as you describe. Curing an excess deceleration problem by braking and
adding more deceleration is not a sound approach. You are controlling
position mechanically, and perhaps the second derivative of velocity via
air pressure, but not the second derivative. You are adding excess energy
that is mechanical noise showing up as precision error.

Figure out a way to decelerate evenly at the end of travel, so your
mechanism comes to a controlled, smooth stop. You will get better
precision, you will use less energy, and your mechanism will wear slower
and last longer.

"Richard J Kinch" wrote in message
. ..
Buerste writes:

Would I be better off with an electric switch and valve?

The flaw of your design is that you do not control acceleration and
deceleration, which not only is brutal, but prohibits precision control
such as you describe. Curing an excess deceleration problem by braking
and
adding more deceleration is not a sound approach. You are controlling
position mechanically, and perhaps the second derivative of velocity via
air pressure, but not the second derivative. You are adding excess energy
that is mechanical noise showing up as precision error.

Figure out a way to decelerate evenly at the end of travel, so your
mechanism comes to a controlled, smooth stop. You will get better
precision, you will use less energy, and your mechanism will wear slower
and last longer.

The obvious method would be to use a servo and program in the ramps. Too
expensive at this point, maybe in the future.

I have considered a hydraulic damper near the end of stroke to bleed off the
energy and not abruptly shock the system. But you see why if I unclamp the
wire, because it has so little mass it's momentum is negligible. The trick
I see is unclamping it at the right time so it coasts to a stop at the right
place against the steel block at the far end.

Buerste wrote:
"Richard J Kinch" wrote in message
. ..
Buerste writes:

Would I be better off with an electric switch and valve?
The flaw of your design is that you do not control acceleration and
deceleration, which not only is brutal, but prohibits precision control
such as you describe. Curing an excess deceleration problem by braking
and
adding more deceleration is not a sound approach. You are controlling
position mechanically, and perhaps the second derivative of velocity via
air pressure, but not the second derivative. You are adding excess energy
that is mechanical noise showing up as precision error.

Figure out a way to decelerate evenly at the end of travel, so your
mechanism comes to a controlled, smooth stop. You will get better
precision, you will use less energy, and your mechanism will wear slower
and last longer.

The obvious method would be to use a servo and program in the ramps. Too
expensive at this point, maybe in the future.

I have considered a hydraulic damper near the end of stroke to bleed off the
energy and not abruptly shock the system. But you see why if I unclamp the
wire, because it has so little mass it's momentum is negligible. The trick
I see is unclamping it at the right time so it coasts to a stop at the right
place against the steel block at the far end.


So the system is over constrained, with the wire both being held by the
roller and by the steel block? Ooh, bad you.

If the wire's momentum is negligible, can you adjust the tension on the
clamping gears so that as soon as it hits the block it stops? Or do the
gears fly back a bit after they stop at full extent?

I think a shock absorber on the cylinder (not 'damper', not for this, in
the US at least -- believe me, I've been living the terminology for the
last few months on That Damned Gate Project) would work quite well,
particularly if you could arrange for it to have a bit of a progressive
action. You can get little screw-in shock absorbers that are spring
loaded, damp when something lands on them, then return to 'out' when you
retract whatever it is that is pushing on the thing.

I'll bet you could select one of those that would work quite well,
particularly if you put a spring on the end of it so that deceleration
force is progressive rather than getting applied suddenly.

Alternately you could valve the cylinder so that as it gets close to
full extent the feed gets choked off -- I couldn't tell without doing
the math, but it seems like there'd be a 'right' combination of cut off
position and residual valve opening that would start bleeding off the
speed while still providing enough flow to complete the stroke at an
appropriately slow rate. In theory this would act exactly like the
shock absorber I'm suggesting, just using the cylinder as the damper and
the air as the working fluid.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

Can you just slow it down a little by restricting the airflow into the
cylinders?

-----
Regards,
Carl Ijames

"Richard J Kinch" wrote in message
. ..
Buerste writes:

Would I be better off with an electric switch and valve?

The flaw of your design is that you do not control acceleration and
deceleration, which not only is brutal, but prohibits precision control
such as you describe. Curing an excess deceleration problem by braking
and
adding more deceleration is not a sound approach. You are controlling
position mechanically, and perhaps the second derivative of velocity via
air pressure, but not the second derivative. You are adding excess energy
that is mechanical noise showing up as precision error.

Figure out a way to decelerate evenly at the end of travel, so your
mechanism comes to a controlled, smooth stop. You will get better
precision, you will use less energy, and your mechanism will wear slower
and last longer.

Tom

If I understand your application correctly, this just screams for a servo
motor.

I used to work with Parker Compumotor products. They have unbelievably top
notch customer service. I'd at least give them a call. Programming one of
these compumotor units is very simple.

Karl

Buerste wrote:
Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft to
rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is meshed
into the first gear with pressure from another air cylinder. Wire is fed
between the gears in a grove cut in the face of each gear. The idea is to
feed wire 3" per stroke.



If these are 3" cuts, separate the operations.
Cut, pieces fall into sorting/stacking bin, a different machine feeds
the cuts to your existing machine.


technomaNge
--
Due to anticipated high turnout in 2010's election,
the Electorial College has scheduled:

Nov. 1, 2010 All Independents vote.
Nov. 2, 2010 All Republicans vote.
Nov. 3, 2010 All Democrats vote.

On Mar 4, 1:31*pm, "Buerste" wrote:
Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft to
rotate the shaft about 90 deg. *On the shaft is a gear with a one-way
clutch. *The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. *By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. *A second gear is meshed
into the first gear with pressure from another air cylinder. *Wire is fed
between the gears in a grove cut in the face of each gear. *The idea is to
feed wire 3" per stroke.

Is works perfectly and fast! *By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire..
I've considered lightening the gears by drilling a bunch of holes. *Also, a
drag brake on one or both gears with screws pressing brass pucks against it.
Another idea is an air limit switch that is struck at the end of the stroke
by the crank. *This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in time?
Would I be better off with an electric switch and valve? *I might have to
lighten the gears, brake them and switch off the air clamp *The feed has to
take place in 300ms.

Bimba makes air cylinders with adjustable internal air cushions.
Maybe if you used one of those to cushion the end of the 1.5 x 4"
cylinder's stroke, it might be enough to slow the wire feed gears
enough (with the one-way clutch still engaged) so they don't
freewheel.
http://www.bimba.com/Products/Origin...tableCushions/
The largest diameter cylinder in the above link is 3", but you might
ask a rep if he can supply one similar to the air cylinder you're
using.

On Thu, 4 Mar 2010 14:31:33 -0500, "Buerste"
wrote:

Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft to
rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is meshed
into the first gear with pressure from another air cylinder. Wire is fed
between the gears in a grove cut in the face of each gear. The idea is to
feed wire 3" per stroke.

Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.
I've considered lightening the gears by drilling a bunch of holes. Also, a
drag brake on one or both gears with screws pressing brass pucks against it.
Another idea is an air limit switch that is struck at the end of the stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in time?
Would I be better off with an electric switch and valve? I might have to
lighten the gears, brake them and switch off the air clamp The feed has to
take place in 300ms.

I'd say you need to do better at defining your objective without
trying to preserve ego invested in design thus far. The only
objective I see stated here is to move wire 3" in 300 milliseconds. I
suspect that there are further unstated constraints or strong wants.

"Carl Ijames" wrote in message
...
Can you just slow it down a little by restricting the airflow into the
cylinders?

-----
Regards,
Carl Ijames

Both cylinders have speed controls on both ends. On the bench, at slow
speed, there is no over-run. But I have a 300ms window to feed.

"Karl Townsend" wrote in message
news.com...
Tom

If I understand your application correctly, this just screams for a servo
motor.

I used to work with Parker Compumotor products. They have unbelievably top
notch customer service. I'd at least give them a call. Programming one of
these compumotor units is very simple.

Karl



I figure about $2500-$3,000. The guys at Carlson Tool (they make brush
machines) do a lot of feeds with servos and mechanical methods and they have
servo set-ups that could work. You'd be surprized how beefy it has to be.
My original design uses a servo, but why stop there...the "X" and "Y" axis
on the table might as well be servo driven too. That works great for brush
machines that change set-ups often but this machine never will, so cam
actuation works just fine and is oh so simple.

I don't mind spending the money but I'll explore the mechanical first.

"technomaNge" wrote in message
...
Buerste wrote:
Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft
to rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is
meshed into the first gear with pressure from another air cylinder. Wire
is fed between the gears in a grove cut in the face of each gear. The
idea is to feed wire 3" per stroke.



If these are 3" cuts, separate the operations.
Cut, pieces fall into sorting/stacking bin, a different machine feeds
the cuts to your existing machine.


technomaNge
--

That's how it's done with round wire. With this flat wire, you can never
lose control of it.

"Don Foreman" wrote in message
...
On Thu, 4 Mar 2010 14:31:33 -0500, "Buerste"
wrote:

Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft
to
rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is
meshed
into the first gear with pressure from another air cylinder. Wire is fed
between the gears in a grove cut in the face of each gear. The idea is to
feed wire 3" per stroke.

Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.
I've considered lightening the gears by drilling a bunch of holes. Also,
a
drag brake on one or both gears with screws pressing brass pucks against
it.
Another idea is an air limit switch that is struck at the end of the
stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in time?
Would I be better off with an electric switch and valve? I might have to
lighten the gears, brake them and switch off the air clamp The feed has
to
take place in 300ms.

I'd say you need to do better at defining your objective without
trying to preserve ego invested in design thus far. The only
objective I see stated here is to move wire 3" in 300 milliseconds. I
suspect that there are further unstated constraints or strong wants.


Hmmm, the wire needs to be in place and in control to be cut in the 300ms
window, that's all. This is the third wire feeder design in ten years.
We've had to use different wire manufacturers over the years as some plants
have closed and the qualities of the wire change...this or that feed doesn't
work on this or that wire too well...etc. This feeder is trying to address
the wire that has too much oil, too much scale, lead drag, ect. The wire
manufacturer can't fine-tune their quality any better and they are the only
domestic supplier. We also use a Taiwanese supplier but their QC and
lead-time is worse. Those are the only suppliers in the entire world! And,
there are only 4 customers in the world and we are by far the largest user.

Need something outside the box?

The stops and starts are killing ya. So, don't stop. Put your cutoff
mechanism and clamp on a turntable. Spindle diameter determines length.
You'll probably need multiple stations to get the layout to work, say do
four stations and use a twelve inch circumference spindle. You can use cams,
air or electric solenoids to move devices.

I used to work for a company that made a million rolls of adhesive tape a
day. We had a few of this idea machine for cut to length tape. Of course,
the first machine we made this way was a total POS. We rebuilt it and it was
only crappy. Then we built one from scratch and it would run 24 hours
straight without a stop. Quite a few more operations than you have. The
turntable was eight feet in diameter.

Karl

On Thu, 4 Mar 2010 14:31:33 -0500, the infamous "Buerste"
scrawled the following:

Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft to
rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is meshed
into the first gear with pressure from another air cylinder. Wire is fed
between the gears in a grove cut in the face of each gear. The idea is to
feed wire 3" per stroke.

What kind? Mangrove? Orange grove?


Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.

That doesn't sound quite like "perfectly" to me. g


I've considered lightening the gears by drilling a bunch of holes. Also, a
drag brake on one or both gears with screws pressing brass pucks against it.
Another idea is an air limit switch that is struck at the end of the stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in time?
Would I be better off with an electric switch and valve? I might have to
lighten the gears, brake them and switch off the air clamp The feed has to
take place in 300ms.

Why not feed 'em with stepper motors turning the gears, Tawm? That
would be much more precise than having to maintain exact feed tension
and maintain split-second air timing unless you're actually ratcheting
the gears. That design would make for a high-maintenance situ, tho.

--
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943

Buerste wrote:

That's how it's done with round wire. With this flat wire, you can never
lose control of it.

Are you sure about that? I've seen some pretty clever mechanical means
for feeding and orienting small parts. I'm guessing there's something
proprietary about the process, but if you could reveal a bit more
detail, that might be helpful.

One thought I had would be to feed through rollers with one way clutches
to prevent the wire from slipping backward. Then feed through a set of
jaws that work like those on strapping tape tension tools. These jaws
would be on a linear slide, to be reciprocated by a crank. The mechanics
of the crank will provide deceleration at both ends of travel. Stroke
length easily adjustable in the same fashion used by shapers.
Either an electromagnetic clutch or a servo motor to drive the crank, if
there is need for dwell between each feed cycle.


Jon

Let the Record show that "Buerste" on or about
Thu, 4 Mar 2010 14:31:33 -0500 did write/type or cause to appear in
rec.crafts.metalworking the following:

Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.
I've considered lightening the gears by drilling a bunch of holes. Also, a
drag brake on one or both gears with screws pressing brass pucks against it.
Another idea is an air limit switch that is struck at the end of the stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Sounds like a "delay" between when you say "stop" and it does
actually stop. Reminds me of a story about teaching a bunch of
farmers to use small boats. They were used to tractors, which only
turn when the steering wheel turned. Turn the wheel hard over, make a
90 degree turn, then straighten the wheel, "plow on". Small boats,
otoh, keep turning. One needs to stop 'turning' before completing the
turn, so that the boat is going "straight" when it gets to the new
heading.

So "re-calibrate". That is, if X amount of time produces Y amount
of wire, shorten X. Seems to me the air limit switch is an idea for
doing just that. Cut off the air so that the "overrun" produces the
last amount of travel needed to get the right amount of wire. That
"over travel" is not a bug, it is a feature.


pyotr

-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

Larry Jaques wrote:
On Thu, 4 Mar 2010 14:31:33 -0500, the infamous "Buerste"
scrawled the following:

Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft to
rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is meshed
into the first gear with pressure from another air cylinder. Wire is fed
between the gears in a grove cut in the face of each gear. The idea is to
feed wire 3" per stroke.

What kind? Mangrove? Orange grove?


Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.

That doesn't sound quite like "perfectly" to me. g


I've considered lightening the gears by drilling a bunch of holes. Also, a
drag brake on one or both gears with screws pressing brass pucks against it.
Another idea is an air limit switch that is struck at the end of the stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in time?
Would I be better off with an electric switch and valve? I might have to
lighten the gears, brake them and switch off the air clamp The feed has to
take place in 300ms.

Why not feed 'em with stepper motors turning the gears, Tawm? That
would be much more precise than having to maintain exact feed tension
and maintain split-second air timing unless you're actually ratcheting
the gears. That design would make for a high-maintenance situ, tho.

This is kinda sorta the absolutely worst sort of application for
steppers. High acceleration = high torque; steppers don't produce much
torque for their size or power input compared to DC motors, and when you
ask for more torque than they can deliver they lose their place
completely. So pushing a stepper for more torque leads to reliability
issues -- you can sacrifice great chunks of an otherwise enjoyable
engineering career to trying to make an undersized stepper reliably
accelerate and decelerate.

Besides, by the time you get a stepper and a stepper controller designed
in, you could well have designed in a brushless motor and a servo
controller -- and with careful design, the only thing that happens if
your brushless motor lacks oomph is that things slow down a bit.

There are applications for which you'd be crazy to use anything other
than a stepper, by the way -- if you've got space and power to burn, you
only need moderate precision for the speed, and tuning a servo motor may
be a questionable exercise, steppers are superlative little gems. But
"go from point A to point B damn fast and stop" is not a strength of a
stepper, in my experience.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

Let the Record show that Larry Jaques on
or about Fri, 05 Mar 2010 06:17:53 -0800 did write/type or cause to
appear in rec.crafts.metalworking the following:


Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.

That doesn't sound quite like "perfectly" to me. g

Oh it works perfectly, just as designed and built! But the
results aren't what he wanted.
I hate it when machines do what I tell them, not what I want. B-)
-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

On Thu, 04 Mar 2010 13:48:15 -0600, Richard J Kinch
wrote:

Buerste writes:

Would I be better off with an electric switch and valve?

The flaw of your design is that you do not control acceleration and
deceleration, which not only is brutal, but prohibits precision control
such as you describe. Curing an excess deceleration problem by braking and
adding more deceleration is not a sound approach. You are controlling
position mechanically, and perhaps the second derivative of velocity via
air pressure, but not the second derivative. You are adding excess energy
that is mechanical noise showing up as precision error.

Figure out a way to decelerate evenly at the end of travel, so your
mechanism comes to a controlled, smooth stop. You will get better
precision, you will use less energy, and your mechanism will wear slower
and last longer.

Ball screws work very good at this if combined with a PLC and sensor

Gunner

Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.

Gunner Asch wrote:
On Thu, 04 Mar 2010 13:48:15 -0600, Richard J Kinch
wrote:

Buerste writes:

Would I be better off with an electric switch and valve?
The flaw of your design is that you do not control acceleration and
deceleration, which not only is brutal, but prohibits precision control
such as you describe. Curing an excess deceleration problem by braking and
adding more deceleration is not a sound approach. You are controlling
position mechanically, and perhaps the second derivative of velocity via
air pressure, but not the second derivative. You are adding excess energy
that is mechanical noise showing up as precision error.

Figure out a way to decelerate evenly at the end of travel, so your
mechanism comes to a controlled, smooth stop. You will get better
precision, you will use less energy, and your mechanism will wear slower
and last longer.

Ball screws work very good at this if combined with a PLC and sensor


But how to meet the 300ms travel time with just a PLC for control?

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Jon Anderson" wrote in message
...
Buerste wrote:

That's how it's done with round wire. With this flat wire, you can never
lose control of it.

Are you sure about that? I've seen some pretty clever mechanical means for
feeding and orienting small parts. I'm guessing there's something
proprietary about the process, but if you could reveal a bit more detail,
that might be helpful.

One thought I had would be to feed through rollers with one way clutches
to prevent the wire from slipping backward. Then feed through a set of
jaws that work like those on strapping tape tension tools. These jaws
would be on a linear slide, to be reciprocated by a crank. The mechanics
of the crank will provide deceleration at both ends of travel. Stroke
length easily adjustable in the same fashion used by shapers.
Either an electromagnetic clutch or a servo motor to drive the crank, if
there is need for dwell between each feed cycle.


Jon




That basically describes feeder #2 but it's driven by air not a motor. I'll
post pix of some of the feeders we still have along with the new one.

"Karl Townsend" wrote in message
anews.com...
Need something outside the box?

The stops and starts are killing ya. So, don't stop. Put your cutoff
mechanism and clamp on a turntable. Spindle diameter determines length.
You'll probably need multiple stations to get the layout to work, say do
four stations and use a twelve inch circumference spindle. You can use
cams, air or electric solenoids to move devices.

I used to work for a company that made a million rolls of adhesive tape a
day. We had a few of this idea machine for cut to length tape. Of course,
the first machine we made this way was a total POS. We rebuilt it and it
was only crappy. Then we built one from scratch and it would run 24 hours
straight without a stop. Quite a few more operations than you have. The
turntable was eight feet in diameter.

Karl


I can visualize that!

"pyotr filipivich" wrote in message
...
Let the Record show that Larry Jaques on
or about Fri, 05 Mar 2010 06:17:53 -0800 did write/type or cause to
appear in rec.crafts.metalworking the following:


Is works perfectly and fast! By varying the pressure in the cylinder
that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much
wire.

That doesn't sound quite like "perfectly" to me. g

Oh it works perfectly, just as designed and built! But the
results aren't what he wanted.
I hate it when machines do what I tell them, not what I want. B-)
-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

My sediments exactly!

"pyotr filipivich" wrote in message
...
Let the Record show that "Buerste" on or about
Thu, 4 Mar 2010 14:31:33 -0500 did write/type or cause to appear in
rec.crafts.metalworking the following:

Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.
I've considered lightening the gears by drilling a bunch of holes. Also,
a
drag brake on one or both gears with screws pressing brass pucks against
it.
Another idea is an air limit switch that is struck at the end of the
stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Sounds like a "delay" between when you say "stop" and it does
actually stop. Reminds me of a story about teaching a bunch of
farmers to use small boats. They were used to tractors, which only
turn when the steering wheel turned. Turn the wheel hard over, make a
90 degree turn, then straighten the wheel, "plow on". Small boats,
otoh, keep turning. One needs to stop 'turning' before completing the
turn, so that the boat is going "straight" when it gets to the new
heading.

So "re-calibrate". That is, if X amount of time produces Y amount
of wire, shorten X. Seems to me the air limit switch is an idea for
doing just that. Cut off the air so that the "overrun" produces the
last amount of travel needed to get the right amount of wire. That
"over travel" is not a bug, it is a feature.


pyotr

-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

Yep! But I hate these "Kentucky Windage" things!

"Larry Jaques" wrote in message
...
On Thu, 4 Mar 2010 14:31:33 -0500, the infamous "Buerste"
scrawled the following:

Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft
to
rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is
meshed
into the first gear with pressure from another air cylinder. Wire is fed
between the gears in a grove cut in the face of each gear. The idea is to
feed wire 3" per stroke.

What kind? Mangrove? Orange grove?


Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.

That doesn't sound quite like "perfectly" to me. g


I've considered lightening the gears by drilling a bunch of holes. Also,
a
drag brake on one or both gears with screws pressing brass pucks against
it.
Another idea is an air limit switch that is struck at the end of the
stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in time?
Would I be better off with an electric switch and valve? I might have to
lighten the gears, brake them and switch off the air clamp The feed has
to
take place in 300ms.

Why not feed 'em with stepper motors turning the gears, Tawm? That
would be much more precise than having to maintain exact feed tension
and maintain split-second air timing unless you're actually ratcheting
the gears. That design would make for a high-maintenance situ, tho.

--
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943


You're always so MEAN to me!

Steppers don't have the speed or oomph and I'm a "MECHANICAL" engineer! Get
it...mechanical??? Anybody can just stick in electronics but it takes a
mechanical guy to do a "Rube Goldberg".

Buerste wrote:
"Larry Jaques" wrote in message
...
On Thu, 4 Mar 2010 14:31:33 -0500, the infamous "Buerste"
scrawled the following:

Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a
shaft to
rotate the shaft about 90 deg. On the shaft is a gear with a
one-way clutch. The 4" x 1/2" gear turns about 3" at the perimeter
per stroke of the cylinder. By moving the link to the air cylinder
up or down on the crank the gear will rotate more or less per
stroke. A second gear is meshed
into the first gear with pressure from another air cylinder. Wire
is fed between the gears in a grove cut in the face of each gear. The
idea is to feed wire 3" per stroke.

What kind? Mangrove? Orange grove?


Is works perfectly and fast! By varying the pressure in the
cylinder that presses the gears together, the wire is gripped very
well at 60 lbs air pressure and will slip through the gears easily
at no pressure. The only problem I have is that the gears over-run and
feed too
much wire.

That doesn't sound quite like "perfectly" to me. g


I've considered lightening the gears by drilling a bunch of holes. Also,
a
drag brake on one or both gears with screws pressing brass pucks
against it.
Another idea is an air limit switch that is struck at the end of the
stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in
time? Would I be better off with an electric switch and valve? I
might have to lighten the gears, brake them and switch off the air
clamp The feed has to
take place in 300ms.

Why not feed 'em with stepper motors turning the gears, Tawm? That
would be much more precise than having to maintain exact feed tension
and maintain split-second air timing unless you're actually
ratcheting the gears. That design would make for a high-maintenance
situ, tho. --
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943


You're always so MEAN to me!

Steppers don't have the speed or oomph and I'm a "MECHANICAL"
engineer! Get it...mechanical??? Anybody can just stick in
electronics but it takes a mechanical guy to do a "Rube Goldberg".

could you stop it with electromagnets?

Buerste wrote:

That basically describes feeder #2 but it's driven by air not a motor. I'll
post pix of some of the feeders we still have along with the new one.


Would love to see a picture of #2. If I get what you're saying above,
you were using an air cylinder to advance the one-way jaw in a linear
fashion? If so... I'm talking about a crankshaft and connecting rod type
setup. Though the crank rotates at a constant velocity, the linear
output slows to a smooth stop at each end of travel.

But a picture's worth a thousand words... I'll watch for your posting of
them.


Jon

Buerste wrote:
"Larry Jaques" wrote in message
...
On Thu, 4 Mar 2010 14:31:33 -0500, the infamous "Buerste"
scrawled the following:

Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft
to
rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is
meshed
into the first gear with pressure from another air cylinder. Wire is fed
between the gears in a grove cut in the face of each gear. The idea is to
feed wire 3" per stroke.
What kind? Mangrove? Orange grove?


Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.
That doesn't sound quite like "perfectly" to me. g


I've considered lightening the gears by drilling a bunch of holes. Also,
a
drag brake on one or both gears with screws pressing brass pucks against
it.
Another idea is an air limit switch that is struck at the end of the
stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in time?
Would I be better off with an electric switch and valve? I might have to
lighten the gears, brake them and switch off the air clamp The feed has
to
take place in 300ms.
Why not feed 'em with stepper motors turning the gears, Tawm? That
would be much more precise than having to maintain exact feed tension
and maintain split-second air timing unless you're actually ratcheting
the gears. That design would make for a high-maintenance situ, tho.

--
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943


You're always so MEAN to me!

Steppers don't have the speed or oomph and I'm a "MECHANICAL" engineer! Get
it...mechanical??? Anybody can just stick in electronics but it takes a
mechanical guy to do a "Rube Goldberg".

You wouldn't say that if you read the source code for a few products
with embedded processors. Embedded software is the ultimate Rube
Goldberg artifact, it's just well hidden.

You shred mechanical drawings so your competitors can't copy your product.

You shred electrical drawings so your competitors can't get an idea of
how you think.

You shred source code so your competitors won't laugh at you.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

Buerste wrote:
"pyotr filipivich" wrote in message
...
Let the Record show that "Buerste" on or about
Thu, 4 Mar 2010 14:31:33 -0500 did write/type or cause to appear in
rec.crafts.metalworking the following:
Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.
I've considered lightening the gears by drilling a bunch of holes. Also,
a
drag brake on one or both gears with screws pressing brass pucks against
it.
Another idea is an air limit switch that is struck at the end of the
stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.
Sounds like a "delay" between when you say "stop" and it does
actually stop. Reminds me of a story about teaching a bunch of
farmers to use small boats. They were used to tractors, which only
turn when the steering wheel turned. Turn the wheel hard over, make a
90 degree turn, then straighten the wheel, "plow on". Small boats,
otoh, keep turning. One needs to stop 'turning' before completing the
turn, so that the boat is going "straight" when it gets to the new
heading.

So "re-calibrate". That is, if X amount of time produces Y amount
of wire, shorten X. Seems to me the air limit switch is an idea for
doing just that. Cut off the air so that the "overrun" produces the
last amount of travel needed to get the right amount of wire. That
"over travel" is not a bug, it is a feature.

Yep! But I hate these "Kentucky Windage" things!

They have a nasty tendency to change with time and temperature. You
want the machine to serve you, not the other way around.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"chaniarts" wrote in message
...
Buerste wrote:
"Larry Jaques" wrote in message
...
On Thu, 4 Mar 2010 14:31:33 -0500, the infamous "Buerste"
scrawled the following:

Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a
shaft to
rotate the shaft about 90 deg. On the shaft is a gear with a
one-way clutch. The 4" x 1/2" gear turns about 3" at the perimeter
per stroke of the cylinder. By moving the link to the air cylinder
up or down on the crank the gear will rotate more or less per
stroke. A second gear is meshed
into the first gear with pressure from another air cylinder. Wire
is fed between the gears in a grove cut in the face of each gear. The
idea is to feed wire 3" per stroke.

What kind? Mangrove? Orange grove?


Is works perfectly and fast! By varying the pressure in the
cylinder that presses the gears together, the wire is gripped very
well at 60 lbs air pressure and will slip through the gears easily
at no pressure. The only problem I have is that the gears over-run and
feed too
much wire.

That doesn't sound quite like "perfectly" to me. g


I've considered lightening the gears by drilling a bunch of holes.
Also, a
drag brake on one or both gears with screws pressing brass pucks
against it.
Another idea is an air limit switch that is struck at the end of the
stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in
time? Would I be better off with an electric switch and valve? I
might have to lighten the gears, brake them and switch off the air
clamp The feed has to
take place in 300ms.

Why not feed 'em with stepper motors turning the gears, Tawm? That
would be much more precise than having to maintain exact feed tension
and maintain split-second air timing unless you're actually
ratcheting the gears. That design would make for a high-maintenance
situ, tho. --
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943


You're always so MEAN to me!

Steppers don't have the speed or oomph and I'm a "MECHANICAL"
engineer! Get it...mechanical??? Anybody can just stick in
electronics but it takes a mechanical guy to do a "Rube Goldberg".

could you stop it with electromagnets?


Sure, a magnetic particle brake is being considered as well as an air
caliper brake.

"Tim Wescott" wrote in message
...
Buerste wrote:
"Larry Jaques" wrote in message
...
On Thu, 4 Mar 2010 14:31:33 -0500, the infamous "Buerste"
scrawled the following:

Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a
shaft to
rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke
of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is
meshed
into the first gear with pressure from another air cylinder. Wire is
fed
between the gears in a grove cut in the face of each gear. The idea is
to
feed wire 3" per stroke.
What kind? Mangrove? Orange grove?


Is works perfectly and fast! By varying the pressure in the cylinder
that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much
wire.
That doesn't sound quite like "perfectly" to me. g


I've considered lightening the gears by drilling a bunch of holes.
Also, a
drag brake on one or both gears with screws pressing brass pucks
against it.
Another idea is an air limit switch that is struck at the end of the
stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in
time?
Would I be better off with an electric switch and valve? I might have
to
lighten the gears, brake them and switch off the air clamp The feed
has to
take place in 300ms.
Why not feed 'em with stepper motors turning the gears, Tawm? That
would be much more precise than having to maintain exact feed tension
and maintain split-second air timing unless you're actually ratcheting
the gears. That design would make for a high-maintenance situ, tho.

--
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943


You're always so MEAN to me!

Steppers don't have the speed or oomph and I'm a "MECHANICAL" engineer!
Get it...mechanical??? Anybody can just stick in electronics but it
takes a mechanical guy to do a "Rube Goldberg".

You wouldn't say that if you read the source code for a few products with
embedded processors. Embedded software is the ultimate Rube Goldberg
artifact, it's just well hidden.

You shred mechanical drawings so your competitors can't copy your product.

You shred electrical drawings so your competitors can't get an idea of how
you think.

You shred source code so your competitors won't laugh at you.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

My good friends at Carlson Tool, they make brush machines, does machine
shows in China. They change the labels on the servo gear boxes so that the
gear ratios are WAY off.

"Tim Wescott" wrote in message
...
Buerste wrote:
"pyotr filipivich" wrote in message
...
Let the Record show that "Buerste" on or about
Thu, 4 Mar 2010 14:31:33 -0500 did write/type or cause to appear in
rec.crafts.metalworking the following:
Is works perfectly and fast! By varying the pressure in the cylinder
that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much
wire.
I've considered lightening the gears by drilling a bunch of holes.
Also, a
drag brake on one or both gears with screws pressing brass pucks
against it.
Another idea is an air limit switch that is struck at the end of the
stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.
Sounds like a "delay" between when you say "stop" and it does
actually stop. Reminds me of a story about teaching a bunch of
farmers to use small boats. They were used to tractors, which only
turn when the steering wheel turned. Turn the wheel hard over, make a
90 degree turn, then straighten the wheel, "plow on". Small boats,
otoh, keep turning. One needs to stop 'turning' before completing the
turn, so that the boat is going "straight" when it gets to the new
heading.

So "re-calibrate". That is, if X amount of time produces Y amount
of wire, shorten X. Seems to me the air limit switch is an idea for
doing just that. Cut off the air so that the "overrun" produces the
last amount of travel needed to get the right amount of wire. That
"over travel" is not a bug, it is a feature.

Yep! But I hate these "Kentucky Windage" things!

They have a nasty tendency to change with time and temperature. You want
the machine to serve you, not the other way around.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

It has to do with the planet Mercury...

Buerste wrote:
"Tim Wescott" wrote in message
...
Buerste wrote:
"pyotr filipivich" wrote in message
...
Let the Record show that "Buerste" on or
about Thu, 4 Mar 2010 14:31:33 -0500 did write/type or cause to
appear in rec.crafts.metalworking the following:
Is works perfectly and fast! By varying the pressure in the
cylinder that
presses the gears together, the wire is gripped very well at 60
lbs air pressure and will slip through the gears easily at no
pressure. The only problem I have is that the gears over-run and feed
too
much wire.
I've considered lightening the gears by drilling a bunch of holes.
Also, a
drag brake on one or both gears with screws pressing brass pucks
against it.
Another idea is an air limit switch that is struck at the end of
the stroke
by the crank. This switch would unload the pressure on the
clamping cylinder and let the wire slip between the gears when
they over-run.
Sounds like a "delay" between when you say "stop" and it does
actually stop. Reminds me of a story about teaching a bunch of
farmers to use small boats. They were used to tractors, which only
turn when the steering wheel turned. Turn the wheel hard over,
make a 90 degree turn, then straighten the wheel, "plow on". Small
boats, otoh, keep turning. One needs to stop 'turning' before
completing the turn, so that the boat is going "straight" when it
gets to the new heading.

So "re-calibrate". That is, if X amount of time produces Y amount
of wire, shorten X. Seems to me the air limit switch is an idea
for doing just that. Cut off the air so that the "overrun"
produces the last amount of travel needed to get the right amount
of wire. That "over travel" is not a bug, it is a feature.

Yep! But I hate these "Kentucky Windage" things!

They have a nasty tendency to change with time and temperature. You
want the machine to serve you, not the other way around.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

It has to do with the planet Mercury...

it's the phase of the moon

On 3/5/2010 12:17 PM, Tim Wescott wrote:
you could well have designed in a brushless motor

Tom doesn't do brushless.

Kevin Gallimore

On Fri, 5 Mar 2010 14:04:37 -0500, the infamous "Buerste"
scrawled the following:


"pyotr filipivich" wrote in message
.. .
Let the Record show that Larry Jaques on
or about Fri, 05 Mar 2010 06:17:53 -0800 did write/type or cause to
appear in rec.crafts.metalworking the following:


Is works perfectly and fast! By varying the pressure in the cylinder
that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much
wire.

That doesn't sound quite like "perfectly" to me. g

Oh it works perfectly, just as designed and built! But the
results aren't what he wanted.
I hate it when machines do what I tell them, not what I want. B-)
-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

My sediments exactly!

Sedimentary, my dear Watson.

--
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943

On Fri, 5 Mar 2010 14:01:17 -0500, the infamous "Buerste"
scrawled the following:


"Karl Townsend" wrote in message
tanews.com...
Need something outside the box?

The stops and starts are killing ya. So, don't stop. Put your cutoff
mechanism and clamp on a turntable. Spindle diameter determines length.
You'll probably need multiple stations to get the layout to work, say do
four stations and use a twelve inch circumference spindle. You can use
cams, air or electric solenoids to move devices.

I used to work for a company that made a million rolls of adhesive tape a
day. We had a few of this idea machine for cut to length tape. Of course,
the first machine we made this way was a total POS. We rebuilt it and it
was only crappy. Then we built one from scratch and it would run 24 hours
straight without a stop. Quite a few more operations than you have. The
turntable was eight feet in diameter.

Karl


I can visualize that!

Yeah, the exact opposite effect of shooting machine gun rounds between
the prop blades on a WWI fighter. But when the timing's off, it goes
through a helluva lot of material in a short period.

--
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943

axolotl wrote in news:hms297$nfb$1
@news.eternal-september.org:

On 3/5/2010 12:17 PM, Tim Wescott wrote:
you could well have designed in a brushless motor

Tom doesn't do brushless.

Kevin Gallimore

Good one.

On Fri, 5 Mar 2010 14:11:32 -0500, the infamous "Buerste"
scrawled the following:


"Larry Jaques" wrote in message
.. .
On Thu, 4 Mar 2010 14:31:33 -0500, the infamous "Buerste"
scrawled the following:

Damn inertia!

I have an air cylinder, 1.5" x 4" stroke, that pushes a crank on a shaft
to
rotate the shaft about 90 deg. On the shaft is a gear with a one-way
clutch. The 4" x 1/2" gear turns about 3" at the perimeter per stroke of
the cylinder. By moving the link to the air cylinder up or down on the
crank the gear will rotate more or less per stroke. A second gear is
meshed
into the first gear with pressure from another air cylinder. Wire is fed
between the gears in a grove cut in the face of each gear. The idea is to
feed wire 3" per stroke.

What kind? Mangrove? Orange grove?


Is works perfectly and fast! By varying the pressure in the cylinder that
presses the gears together, the wire is gripped very well at 60 lbs air
pressure and will slip through the gears easily at no pressure.

The only problem I have is that the gears over-run and feed too much wire.

That doesn't sound quite like "perfectly" to me. g


I've considered lightening the gears by drilling a bunch of holes. Also,
a
drag brake on one or both gears with screws pressing brass pucks against
it.
Another idea is an air limit switch that is struck at the end of the
stroke
by the crank. This switch would unload the pressure on the clamping
cylinder and let the wire slip between the gears when they over-run.

Would the air limit switch work fast enough to unclamp the wire in time?
Would I be better off with an electric switch and valve? I might have to
lighten the gears, brake them and switch off the air clamp The feed has
to
take place in 300ms.

Why not feed 'em with stepper motors turning the gears, Tawm? That
would be much more precise than having to maintain exact feed tension
and maintain split-second air timing unless you're actually ratcheting
the gears. That design would make for a high-maintenance situ, tho.

--
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943


You're always so MEAN to me!

I'll take that as "orange grove", then. Thanks.


Steppers don't have the speed or oomph

Really? What kind of forces are we talkin' here? Is your leetle thang
physically tugging on the gigantic 2T spool of wire?


and I'm a "MECHANICAL" engineer! Get
it...mechanical??? Anybody can just stick in electronics but it takes a
mechanical guy to do a "Rube Goldberg".

If I'd gone to college, I'd have taken both courses and come out an
EME who could leap over tall buildings in a single electromechanical
bound!

Well, since you're too tightarsed to go with servos, Rube away, sir!

--
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943

On Fri, 5 Mar 2010 17:33:25 -0500, the infamous "Buerste"
scrawled the following:


"chaniarts" wrote in message
...
could you stop it with electromagnets?

Sure, a magnetic particle brake is being considered as well as an air
caliper brake.

Then what do you do with the magnetized bits of wire? 8-/

--
An author spends months writing a book, and maybe puts his
heart's blood into it, and then it lies about unread till
the reader has nothing else in the world to do.
-- W. Somerset Maugham, The Razor's Edge, 1943