My pneumatic counterbalance

[davo727]

When I had the gearbox apart I installed brackets to the top about halfway between the motor and spindle for counterbalance cables to attach to. Made up brackets to mount the pulleys to. They are 2 1/2 in steel from grainger. The cables are vinyl coated 1/8 in. The cylinder is 3.25 in bore, 21 in stroke. New unit off ebay $50.00 to the house Hose runs from a 9 gal air tank to the rod end side of the cylinder. 40 psi in the tank seems to work great, gives about 240 lb of pull on the cables. Im going to add one more cross brace to the pulley mount and then i will pull it off and paint it. I will also mount the tank up under the stand.Dave

[davo727]

Another pic, Im going to add another cross brace toward the rear of the bracket. The two cables attach to a 8 in long tie bracket that hooks to the cylinder. Pics not too good sorry.

[r.r.mccoy]

Hi Davo,

Do you need to add air to the tank or is it used as a ballast?

[davo727]

Hi, The tank is just charged to 40psi and left. It acts as an accumulator and as the mill head goes up and down the air transfers back and forth between the cylinder and the tank. Dave

[r.r.mccoy]

Thanks

I've a heavy gantry motor and I think this will be how I set it up. I was concerned about taxing my small compressor by displacing so much air. Now I don't need to worry about that.

Cheers

[Ron111]

Pretty slick, Thanks for the reply on the HM-52 Chich thread. Quick question, how are these cylinders rated? Say for example, your head and motor weigh some 250lbs where as Chich's knee and table some 500? so what is the methodology used for the correct sizing and pressure required. I realize there is usually a little "you figure it out when you get to play with it".

So, if there is a little insite you could share concerning the sizing for specified load, I'm all ears.

Thanks

Ron

[Runner4404spd]

ron,

since you know the weight of the head = 250 lbs, thats the load you need to counter balance. on this particular setup he is using the rod of the cylinder so.... assume a 3" bore and a 1" rod

pi X D^2 / 4 - pi X d^2 /4 = working surface area = 6.28 in^2

weight of the head = 250 lbs = 6.28 x psi
psi = 39.8 psi

wow, good guess on my part, the numbers kinda worked out. for this setup you only need to watch out for air leakage. i would put some kind of pressure regulator onto the tank and keep it charged with a compressor while working.

[davo727]

Hi, Here is an online pneumatic force calculator: http://www.aircylindersdirect.com/we...calcType=force It will give you the pull and push force for a given size cylinder and pressure entered. Dave

[Ron111]

Thanks,
Guys

[hoan]

hi! everybody
I am still a student from viet nam .
my teacher gave me a reseach title about couter balance a few days ago ,
but he didn't gave me any document of it so that I met very much difficuties
now I need help
everybody ! please send me any document or basic principle of counter balance if you have
thank you very much !
please send to " mystar.bkc@gmail.com"

[srinivasananand]

hi i am facing problem on Z axis when power goes off the Z axis is dropping by 2mm to 4mm . please help me to fix the issue. need pneumatic counter balancing design.

[balajisah]

Hi! I need pneumatic circuit for the counter balance mechanism. Also give list of materials required to build a one.

Thanks

Balaji