Hydraulic Side Tilt For 3PH--Single or Double Acting?

[LD1]

Most truly single acting cylinders are extend only. They are cheap, and don't even have a piston or seals. Just gland packing. And they would have no load holding ability.

A single acting cylinder that is powered under retract only is gonna be a double acting cylinder that just has a breather in the base port. So what are you saving? $20-$30 of hose and fittings?

But yes, in theory...a SA cylinder "could" work if you powered the rod port. Because you really don't need power to extend because gravity can do that for you by forcing over the relief

But again, why? To save a few bucks?
The selection of DA cylinders is far greater that SA cylinders.

 

[Vigo327]

Well so far im in the double acting camp but im still glad this thread came along because i challenge conventional wisdom all the time and would have had to work through the possible issues in my head anyway if i didn't read them here first. Saves me a little time on a long list of rabbit hole ideas.

 

[3 Horse Ranch]

Most truly single acting cylinders are extend only. They are cheap, and don't even have a piston or seals. Just gland packing. And they would have no load holding ability.

I really question the validity of this statement. I agree they extend only, hence the "single acting" but the rest of it is questionable at best. Maybe you have a certain kind of small cylinder in mind, but your statement doesn't hold true for larger single acting cylinders.

 

[LD1]

I really question the validity of this statement. I agree they extend only, hence the "single acting" but the rest of it is questionable at best. Maybe you have a certain kind of small cylinder in mind, but your statement doesn't hold true for larger single acting cylinders.

Quite a few cylinders that are marketed as SA are constructed as DA cylinders with a breather in one port.

But true SA cylinders like I am referring to are found on things like snowplow angle or lift cylinders

 

[3 Horse Ranch]

Quite a few cylinders that are marketed as SA are constructed as DA cylinders with a breather in one port.

But true SA cylinders like I am referring to are found on things like snowplow angle or lift cylinders

I guess I was thinking of things like forklift main cylinder, dump truck lift cylinder, bottle jacks etc as being true single acting cylinders, I don't remember a breather on any of those. But then they are designed to lift and hold weight.

 

[ovrszd]

I see no advantage to single acting cylinder.

I use my double acting cylinder to push one side or the other of the attachment down. The push is achieved by applying the weight of the attachment on one small edge. Such as a BB or rear blade.

If I'm trying to dig a ditch with my rear blade, and extend the cylinder lifting the entire blade off the ground except the digging end of the moldboard I can dig a ditch in almost any type of dirt.

Or if I'm trying to level a side slope with the BB I can apply the same principle. Making quick work of the challenge.

 

[Xfaxman]

Right, but that means the weight of the attachment moves it down to tilt. What do you do when the attachment hits the ground and you want it lower?

Using the tilt cylinder to push down will just make the 3pt move up. Unless it has down pressure in which case you don't need the tilt cyl to push down.

But the double action tilt cylinder increased the tilt angle. A single action tilt cylinder couldn't do that without raising the 3pt.

This is my double action tilt cylinder. It is in a Tilt-Tach:

It goes on the SSQA:

Then the attachment goes on the Tilt-Tach:

And it tilts the land plane:

Tilting the 6' box blade:

 

[LD1]

I guess I was thinking of things like forklift main cylinder, dump truck lift cylinder, bottle jacks etc as being true single acting cylinders, I don't remember a breather on any of those. But then they are designed to lift and hold weight.

But all of those single acting cylinders also lift by extension.

For a side link cylinder....retraction is needed for lift. And gravity causes extension if a SA cylinder is desired

 

[3 Horse Ranch]

The OPs problem would be without the ground limiting travel the cylinder will just extend on it's own and it would never hold adjustment. It needs to be a hard connection limited in both directions. Otherwise when he lifts the three point the side with the single acting cylinder will just drop as far as the length of the ram will allow.

 

[Xfaxman]

Otherwise when he lifts the three point the side with the single acting cylinder will just drop as far as the length of the ram will allow.

I thought the closed valve would prevent that by keeping the fluid in the rod side.

 

[npalen]

Quite a few cylinders that are marketed as SA are constructed as DA cylinders with a breather in one port.

But true SA cylinders like I am referring to are found on things like snowplow angle or lift c

The OPs problem would be without the ground limiting travel the cylinder will just extend on it's own and it would never hold adjustment. It needs to be a hard connection limited in both directions. Otherwise when he lifts the three point the side with the single acting cylinder will just drop as far as the length of the ram will allow.

I don't think so.

 

[jdmeth]

I'm just looking for a reason why a single acting cylinder with a double acting valve (single hose) wouldn't work.
It would give a larger selection of cylinders to choose from.

Works just fine. I had a front 3 point hitch I bolted to my 120 hp four wheel drive JD 4250. I ran one hose to it. The lift cylinders rod end ports had a fitting with an air filter in it. Raising the lift forced air out and filtered air would be sucked back in when I lowered the lift. This also allowed the attached implement to float up, air would be forced out and a vacuum pulled on the pressure side. Worked great.

Of course the cylinders were mounted to the base and lifted by extension, like the boom on a backhoe. Using them mounted to lift arms would not work, gravity would just pull the rod out. To work you would have to use a double acting cylinder with the hose plumbed into the rod end and a filter fitted to the piston end.

 

[DSteiner]

Your current vertical lift arms are fixed with an adjustment on one or both. This keeps things on an even keel side to side. A single action cylinder will destroy that ability. For example you want a rear blade to cut deeper on one side in relation to the other.

 

[npalen]

I agree with your thinking as a single acting cylinder would allow that side of the 3PH to float upward without necessarily affecting the other "rigid" side. Yes, that would destroy the desired tilt that had previously been set by retracting or extending the SA cylinder.

There might be a case or two where it is desired to let the SA side float independently when working with existing road crown, for example, but that would probably be an exception.