Print PDF
Favorite
Email
Step 3Fabricate door bracket / install pistons
Next I had to fabricate a bracket to connect the pistons above the door to the actual door. I welded up a bracket out of some steel flat bar from Home Depot and attached it to the back of the door with a spacer block. I could have really used some more advanced tools at this point, but I had to work with what I had at the time. You can fabricate this bracket from sheet metal, steel bar, wood, or whatever you can find.
With the two brackets fabricated and installed, I mounted the two 16" pistons above the door, side by side. Air supplied to the back of the pistons would open the doors, and air supplied to the front of the pistons would close the doors, as seen below. I rigged up the valve temporarily to test everything out.
With the two brackets fabricated and installed, I mounted the two 16" pistons above the door, side by side. Air supplied to the back of the pistons would open the doors, and air supplied to the front of the pistons would close the doors, as seen below. I rigged up the valve temporarily to test everything out.
| « Previous Step | Download PDFView All Steps | Next Step » |
That if there's a power/air failure the doors will automatic open.
but yes.. yer absolutely right.. back from my old Industrial automations day this is how a such a circuit would be wired / piped. standard procedure for a "crush point" would be a closed circuit. as in , the Solenoid engaging the pneumatic cylinder had to be engaged, to engage the tube. loss of control voltage, as in.. turning it off, would send the cylinder to its at rest "open" position.
so.. if you loose power at the house? the holding circuit drops out, and the door opens.
this is standard E-stop stuff, or as we called it in the industry , *slapping the OH SH*T!" button"
At least that's what he told me.
Manual release is handy for lots of things,
But in an Emergency you want it simple and fool proof,
so having it Fail(reset) with the doors open would be ideal.
Someone also mention about the fire risks that's fairly easy to rectify,
Most Commercial Fire Alarms can be setup networked to other Alarms
so there already fitted with extension point, just wire it up to the existing
door circuit (and a bit of tinkering, which we all love to do) then you alarm
will trigger the door to open.
(Personal i could not do that here what with how my other half cooks)
all in all it is a Very good instructable,
Controlling the speed of them closing could be done with flow control valves.
If you want to allow the doors to be forced and held open by hand in the event of a power outage you could use a solenoid valve with a check valve. Setup to allow the now unused ports of the air cylinders to both vent and draw air when power is provided, but only vent (and not draw) air when the power is cut off.
The resulting vacuum in the cylinder will prevent the springs from pulling the doors closed all the way.
If you need a diagram of the above I would be happy to provide one.
If the cylinder is 16 inches long, 3/4 inch round (I.D. I'm guessing) and is actuated with 3 pounds of air pressure, What's the total total pressure that you'd need to apply to force the ram back in?
113 pounds of force is in that ram at just 3 lbs\in sq'd. And that air still doesn't have a place to go. Unless they aren't pressurized when closed and only pressurize when opening. Then they would slide open pretty easily when closed. At least I think they would.
I am trying to be nice, but I have to draw the line somewhere. Your posts are too long and they are misinforming people. Please stop posting.
If the piston is 3/4" bore, the area of the bottom of the piston is 0.5625". At 3 PSI, the force of the piston is 1.7 lbs. Not 113 lbs. Listen to what you are saying. PSI = Pounds per square inch. If the piston were 1 square inch, and you applied 3 pounds, that would be 3 pounds of force.
Even if you had read that my door runs at 30 PSI, that's still less than 17 lbs of force on each door.