Run one past the oh great ones

[Tooljunkie]

Now that i have a box scraper someting new has reared its ugly head. The adjustable side link on my three point is on its last leg. I have a couple small hydraulic cylinders. Picture one on each 3 point link and a valve connecting the 2. As one extends the other retracts. Open valve and implement levels itself while parked on the ground. Need to angle,set one corner on a block and open valve while lowering 3 point. Close valve and away you go. The cylinders im thinking of using are double acting so a second line joining the two open ports should take care of leakdown. I really dislike cranking that adjuster anyway.

Thoughts?

 

[Ramos]

I am not one of the great ones who's counsel you seek.

However, I don't think there is much to be gained by putting a cylinder on BOTH lift arms. If I was going to do it, I would do the top-link and adjustable lift arm only. Those two would give a guy all the 'on-the-fly' adjustability you need.

 

[Tooljunkie]

I am not one of the great ones who's counsel you seek.

However, I don't think there is much to be gained by putting a cylinder on BOTH lift arms. If I was going to do it, I would do the top-link and adjustable lift arm only. Those two would give a guy all the 'on-the-fly' adjustability you need.

Reason for both is i would not be using a hydraulic pump and to have somewhere for the displaced fluid to go.

 

[North Idaho Wolfman]

How you would do it is connect cylinder 1 top port to cylinder 2 bottom port, and Cylinder 2 top port to cylinder 1 bottom port with a valve in between one or the other line.
Ok now why this would't work;
#1: Air in the system, even if you were good enough to purge all the air out of the cylinders, lines and valves, something is going to leak at some point and air will replace fluid.
#2: Fluid expands and shrinks with temp changes, so a closed system without a ballast tank on it is going to pop something, and most likely it will be a seal.

 

[G.rid]

Could it be that simple? It sounds too easy. Lol

I don't see any reason it wouldn't work. Some snowplows and fishing boats use the same set up you described. The volume of oil would be slightly off from one to the other, but has been hosed that way for years.

Remember, pictures when your done.

 

[Tooljunkie]

I considered those points,may put air in upper side, like 5 psi,and a second valve to purge air on lower side. With air on upper side if fluid expands it will allow room for that. Cant cross connect as ram side has less volume then pison end. May use brake fluid as its more temperature stable. Will have to check if brake fluid will harm the seals and hoses.

 

[Ramos]

I did not understand that this would be an external system. Why not add a small reservoir, like two gallons?

 

[Tooljunkie]

Could it be that simple? It sounds too easy. Lol

I don't see any reason it wouldn't work. Some snowplows and fishing boats use the same set up you described. The volume of oil would be slightly off from one to the other, but has been hosed that way for years.

Remember, pictures when your done.

Actually marine steering uses a rack and pinion,rack is a hydraulic cylinder on the end and engine end is a cylinder. Displacement does the steering.

 

[North Idaho Wolfman]

I considered those points,may put air in upper side, like 5 psi,and a second valve to purge air on lower side. With air on upper side if fluid expands it will allow room for that. Cant cross connect as ram side has less volume then pison end. May use brake fluid as its more temperature stable. Will have to check if brake fluid will harm the seals and hoses.

You can't put air in it or it will just act like a shock and compress.
Your three point would be all over the place!

 

[Tooljunkie]

This is my plan of sorts. But using mercury outboard (175hp) trim cylinders. was playing around with it today, think it needs fluid on both ends. Think it will work.

 

[cviola2005]

Since the rod end has a smaller volume than the piston end, mount the cylinders opposite ended to each other (left:rod end up, right:rod end down), connect top to bottom and visa versa, they will displace the same amount of fluid and work as intended.

I like the idea.

My two cents

 

[Tooljunkie]

they can be easily seperated,even have a t block to make it easier to purge air.
The bigger end goes to top,machining a swivel block so they can swing freely. Smaller bottom end will get a shackle of sorts. Have fittings and valves coming in morning.
The cylinders have 3/16" inverted flare, both located on one end so it will be easy to keep fittings up out of the way.

 

[skeets]

This should be interesting

 

[Tooljunkie]

Well, still in experimenting stage. Set up in vise and trying to evacuate air is a challenge. I think im close though. As air gets replaced with oil it gets harder to push and now cylinders move proportionally-as i pull or push one , the other moves in sync. Today i build brackets and top swivel. Forgot to buy bolts.... no worries though,i will rifle through my hardware collection-one thing though.no matter what bolt i go hunting for it seems to be the one i never have. I bet i have 300 plus lbs of assorted hardware 20%new and all kinds of used odds and ends.

Stay tuned....

 

[skeets]

Frank,,, I was looking at the cylinders, are you going to separate them farther apart, and do you think the rods will be heavy enough to take the abuse of the box, being pushed and pulled?

 

[Tooljunkie]

Cylinders are seperated, they were connected by a small hydraulic block.

Imagine the forces involved when a 175 hp mercury v6 pushing a thousand pound boat at almost 80 mph.this i am familiar with. Its scary and fun at the same time. 16.5' hydrostream.
Im confident they will take the stress. Not to mention they have been holding that same motor up in some sort of position since the late 70's. We changed out the center section for a single hydraulic setup, took 25 lbs out of the boat. Not to mention the pump that vents an oily mist into the bilge from time to time. That was the main reason.

 

[skeets]

Cool, I never ran anything that big. ANd I doubt the Bayliner weighed that much but yeah even 50 mph on water is fun and scary when you go air born,,lol

 

[Tooljunkie]

Cool, I never ran anything that big. ANd I doubt the Bayliner weighed that much but yeah even 50 mph on water is fun and scary when you go air born,,lol

This particular hull is a pad-V. A flat spot near transom 14" wide and maybe 24" long. When it gets on step (aired out) its running on that pad. The entire transom goes from 3" freeboard to completely out of the water. And its a handful when its wound out.accelerator pedal on floor and trim switches on steering wheel. Dual cable steering thats tight, zero slack and solid motor mounts. Its a high performance boat. Probably in the top ten fastest boats on this body of water.

 

[Tooljunkie]

Back to regular programming. It tilts either way,and if i open valve it pretty much levels itself. Set on level floor and open valve and its level.
Can get 8" difference in height at lift arms.
Would have been much easier to use conventional hydraulic cylinders as i needed to adapt inverted flare to npt and back to inv flare.

With box scraper all the way up i can stand on either rear corner with no problem.

Need to remember to tighten a couple bolts....and give it a bath,had a couple mishaps with oil...

 

[bucktail]

They look a lot bigger on the tractor than they did on the workbench.