I'm designing a new generation machine that will need to push a 5/8" rod
two inches with about 600 lbs of pressure. It also needs to be a bit
"springy". The new machine is only about 5 cubic feet in volume and
will replace current machines that are 4' x 5' x 6' in volume. The old
machines use hydraulic power for the pin push. I want the entire
machine to use 120VAC only. One option is a small pump and an air
cylinder, another is a linear actuator with an in-line die spring or
something I haven't thought of. The rest of the machine is most of the
way there and rather clever...for me, anyway. What pitfalls can I
expect with a linear actuator?

On 2013-06-04, Tom Gardner Mars@Tacks wrote:
I'm designing a new generation machine that will need to push a 5/8" rod
two inches with about 600 lbs of pressure. It also needs to be a bit
"springy". The new machine is only about 5 cubic feet in volume and
will replace current machines that are 4' x 5' x 6' in volume. The old
machines use hydraulic power for the pin push. I want the entire
machine to use 120VAC only. One option is a small pump and an air
cylinder, another is a linear actuator with an in-line die spring or
something I haven't thought of. The rest of the machine is most of the
way there and rather clever...for me, anyway. What pitfalls can I
expect with a linear actuator?

You can push a threaded rod with a spring attached, using a DC motor
and two micro switches to limit travel.

i

Ignoramus11086 fired this volley in
:

You can push a threaded rod with a spring attached, using a DC motor
and two micro switches to limit travel.


A 2" stroke 3" cylinder produces that much (slightly more) force at 100psi.
That seems the more reliable solution.

Lloyd

On 6/4/2013 10:40 AM, Lloyd E. Sponenburgh wrote:
Ignoramus11086 fired this volley in
:

You can push a threaded rod with a spring attached, using a DC motor
and two micro switches to limit travel.


A 2" stroke 3" cylinder produces that much (slightly more) force at 100psi.
That seems the more reliable solution.

Lloyd


We like air more and more, screw the all electric goal. A small
compressor just doesn't matter.

However, I sure will avoid hydraulics!

On 6/4/2013 9:42 AM, Ignoramus11086 wrote:
On 2013-06-04, Tom Gardner Mars@Tacks wrote:
I'm designing a new generation machine that will need to push a 5/8" rod
two inches with about 600 lbs of pressure. It also needs to be a bit
"springy". The new machine is only about 5 cubic feet in volume and
will replace current machines that are 4' x 5' x 6' in volume. The old
machines use hydraulic power for the pin push. I want the entire
machine to use 120VAC only. One option is a small pump and an air
cylinder, another is a linear actuator with an in-line die spring or
something I haven't thought of. The rest of the machine is most of the
way there and rather clever...for me, anyway. What pitfalls can I
expect with a linear actuator?

You can push a threaded rod with a spring attached, using a DC motor
and two micro switches to limit travel.

i


Yep, ant that would be a good option. I still will figure out how to
get the required push but we;re leaning toward air. Thanks.

Tom Gardner Mars@Tacks fired this volley in news:c6-
:

Yep, ant that would be a good option. I still will figure out how to
get the required push but we;re leaning toward air. Thanks.

Tom,
Not only is air the simpler solution (although I use motorized
positioners, too), but it's just as "springy" as you'd want.

One application I have requires that the pressing rod be able to retract
_instantly_ under explosive force. There's nothing for it, but to use an
air cylinder (with an especially long stroke, in my case) to ensure that
nothing-but-nothing obstructs the travel of that rod if it must be
ejected from the zone by the action of an accident inside the pressing
area.

I.E.-- I might use a 6" stroke for a 2" travel, so that I can make sure
there's not excessive force required to back the rod out of it's zone
when required.


LLoyd

On Tue, 04 Jun 2013 17:56:20 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tom Gardner Mars@Tacks fired this volley in news:c6-
:

Yep, ant that would be a good option. I still will figure out how to
get the required push but we;re leaning toward air. Thanks.

Tom,
Not only is air the simpler solution (although I use motorized
positioners, too), but it's just as "springy" as you'd want.

One application I have requires that the pressing rod be able to retract
_instantly_ under explosive force. There's nothing for it, but to use an
air cylinder (with an especially long stroke, in my case) to ensure that
nothing-but-nothing obstructs the travel of that rod if it must be
ejected from the zone by the action of an accident inside the pressing
area.

I.E.-- I might use a 6" stroke for a 2" travel, so that I can make sure
there's not excessive force required to back the rod out of it's zone
when required.


LLoyd

One way Ive used to set a device to pull fast or slow..is to use an
adjustable volume valve..and on a tee next to it attached to the same
port...a solenoid valve that only opens under an emergency condition.
The "trickle" valve will allow the rate of movement to be
adjusted..there is also a certain amount of spring as the cylinder is
being drawn..but if you get an emergency condition..that solenoid will
open wide and bypass that adjustable "trickle valve" and allow full
speed retraction.


--
"You guess the truth hurts?

Really?

"Hurt" aint the word.

For Liberals, the truth is like salt to a slug.
Sunlight to a vampire.
Raid® to a cockroach.
Sheriff Brody to a shark
Bush to a Liberal

The truth doesn't just hurt. It's painful, like a red hot poker shoved
up their ass. Like sliding down a hundred foot razor blade using their
dick as a brake.

They HATE the truth."

On 6/4/2013 7:46 PM, Gunner Asch wrote:
On Tue, 04 Jun 2013 17:56:20 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tom Gardner Mars@Tacks fired this volley in news:c6-
:

Yep, ant that would be a good option. I still will figure out how to
get the required push but we;re leaning toward air. Thanks.

Tom,
Not only is air the simpler solution (although I use motorized
positioners, too), but it's just as "springy" as you'd want.

One application I have requires that the pressing rod be able to retract
_instantly_ under explosive force. There's nothing for it, but to use an
air cylinder (with an especially long stroke, in my case) to ensure that
nothing-but-nothing obstructs the travel of that rod if it must be
ejected from the zone by the action of an accident inside the pressing
area.

I.E.-- I might use a 6" stroke for a 2" travel, so that I can make sure
there's not excessive force required to back the rod out of it's zone
when required.


LLoyd

One way Ive used to set a device to pull fast or slow..is to use an
adjustable volume valve..and on a tee next to it attached to the same
port...a solenoid valve that only opens under an emergency condition.
The "trickle" valve will allow the rate of movement to be
adjusted..there is also a certain amount of spring as the cylinder is
being drawn..but if you get an emergency condition..that solenoid will
open wide and bypass that adjustable "trickle valve" and allow full
speed retraction.




Cool!

Tom Gardner wrote:

Yep, ant that would be a good option.


What kind of ant? ;-)

On 6/4/2013 7:35 PM, Michael A. Terrell wrote:

Tom Gardner wrote:

Yep, ant that would be a good option.


What kind of ant? ;-)


A dead one! Dead-ant, dead-ant, dead-annnnnt!

Tom Gardner wrote:

On 6/4/2013 7:35 PM, Michael A. Terrell wrote:

Tom Gardner wrote:

Yep, ant that would be a good option.


What kind of ant? ;-)


A dead one! Dead-ant, dead-ant, dead-annnnnt!


Quit panting, Pinkie!!! ;-)

On Tue, 04 Jun 2013 18:49:56 -0400, Tom Gardner Mars@Tacks
wrote:
snip
push a 5/8" rod two inches with about 600 lbs of pressure.

Check out air brake actuators for HD trucks/trailers.

one place to start

http://www.easternmarine.com/Air-Bra...ers-Diaphrams/

On 6/4/2013 9:17 PM, F. George McDuffee wrote:
On Tue, 04 Jun 2013 18:49:56 -0400, Tom Gardner Mars@Tacks
wrote:
snip
push a 5/8" rod two inches with about 600 lbs of pressure.

Check out air brake actuators for HD trucks/trailers.

one place to start

http://www.easternmarine.com/Air-Bra...ers-Diaphrams/





Yep, used them before for blister packing machines, I have a few in stock!

Tom Gardner wrote:

I'm designing a new generation machine that will need to push a 5/8" rod
two inches with about 600 lbs of pressure. It also needs to be a bit
"springy". The new machine is only about 5 cubic feet in volume and
will replace current machines that are 4' x 5' x 6' in volume. The old
machines use hydraulic power for the pin push. I want the entire
machine to use 120VAC only. One option is a small pump and an air
cylinder, another is a linear actuator with an in-line die spring or
something I haven't thought of. The rest of the machine is most of the
way there and rather clever...for me, anyway. What pitfalls can I
expect with a linear actuator?

Not sure what the control / timing requirements are. Would this be
something best done with a continuously running motor, an electric
clutch and a gear drive to a cam type setup?

On 6/4/2013 9:59 AM, Pete C. wrote:

Tom Gardner wrote:

I'm designing a new generation machine that will need to push a 5/8" rod
two inches with about 600 lbs of pressure. It also needs to be a bit
"springy". The new machine is only about 5 cubic feet in volume and
will replace current machines that are 4' x 5' x 6' in volume. The old
machines use hydraulic power for the pin push. I want the entire
machine to use 120VAC only. One option is a small pump and an air
cylinder, another is a linear actuator with an in-line die spring or
something I haven't thought of. The rest of the machine is most of the
way there and rather clever...for me, anyway. What pitfalls can I
expect with a linear actuator?

Not sure what the control / timing requirements are. Would this be
something best done with a continuously running motor, an electric
clutch and a gear drive to a cam type setup?


Plenty of time, 3 seconds to extend or retract. The rest of my staff is
all for air, it just simplifies things and is cheaper. And, air can be
used for clean-up and other things

On Tue, 04 Jun 2013 18:45:37 -0400, Tom Gardner Mars@Tacks wrote:

On 6/4/2013 9:59 AM, Pete C. wrote:

Tom Gardner wrote:

I'm designing a new generation machine that will need to push a 5/8" rod
two inches with about 600 lbs of pressure. It also needs to be a bit
"springy". The new machine is only about 5 cubic feet in volume and
will replace current machines that are 4' x 5' x 6' in volume. The old
machines use hydraulic power for the pin push. I want the entire
machine to use 120VAC only. One option is a small pump and an air
cylinder, another is a linear actuator with an in-line die spring or
something I haven't thought of. The rest of the machine is most of the
way there and rather clever...for me, anyway. What pitfalls can I
expect with a linear actuator?

Not sure what the control / timing requirements are. Would this be
something best done with a continuously running motor, an electric
clutch and a gear drive to a cam type setup?


Plenty of time, 3 seconds to extend or retract. The rest of my staff is
all for air, it just simplifies things and is cheaper. And, air can be
used for clean-up and other things

Air is fine, but it's not so good where you need positive control on
the stroke of that push, so you don't have a Tool Crash when the
follow-up operation tries to happen - unless it has enough brute force
to clear a misshaped or mispositioned workpiece out of the way, and/or
you put a limit switch to make sure it went far enough to do what you
want.

And those truck brake units are handy things - and consider the Spring
Brake ones. You have to apply pressure to release the parking brake
springs, and then you apply air to the other half to get normal
braking. But when it absolutely positively has to fail safe, the
spring (and a dump valve of some sort) makes sure of it.

I notice you deliberately haven't said what this actuator is doing...
Yeah, distributing 5,000 copies of the NDA and making sure they all
got signed and returned would be a problem.

-- Bruce --