bud-- wrote:
On 4/7/2013 10:55 PM, Steve B wrote:
"Tony wrote in message
...
Steve B wrote:
I need an actuator, but one that is air powered preferably. Instead of
the
shaft coming out slowly, I want it to shoot out instantly upon air
pressure
hitting it. What are those called?

Steve


Hi,
Google pneumatic actuator.

Most of what I am finding is much too large for my use. I need about .75"
rod maximum.

Steve


The cylinder attached to a .75" ram will give you enough force to
pulverize your pecans - you can sell pecan-nut-and-shell dust.

You want a rather small cylinder with a larger face, which you can
fabricate easier than most of us.

One method is to spring load the face (may be relatively large springs)
and give the cylinders a short hit of air. You could put a stop on the
extension of the face that would help stop from pulverizing the pecan.
Would think you only need one cylinder, and an 'anvil' on the other side of the pecan.

Another method, 'face piece' is relatively heavy and separate from
cylinder. It is in a guide. Pneumatic cylinder kicks the 'face piece' and
it travels past where the cylinder stops to hit the pecan. Smaller spring
pushes 'face piece' back. This is more complicated but should be more
controllable. It doesn't matter how long an air pulse to the pneumatic
cylinder is. The hit to the pecan largely depends on the weight of the 'face piece'.

Maybe easier, you could put a spring on the back side of the 'anvil' to control the hit.

That is more better. Of all the comments, I think acceleration, force,
mass, destruction of mechanism. Most actuators will specify maximum
pressures. The actuators really needs a soft stop, and the ram will
continue on.

Greg