forgeing splines using a axle and press

[BukitCase]

How are you gonna plumb the two cylinders so they don't bind up due to seriously different displacement on pull vs. push stroke? Steve

I know it CAN be done, my hoe uses a pair of identical trunnion mount cylinders (in push-pull) for the boom swing; I just haven't needed to open THAT particular can-o-worms yet, so no clue...

Edit - think I figured it out; push on one and pull on other cylinder are PARALLELED, same with the OTHER pair of ports - that way, each cylinder gets the fluid it needs, but it'll NEVER be the SAME flow to both cylinders at the same time -

OK, nevermind - that wasn't so hard once I quit bein' LAZY ...Steve

 

[muddstopper]

OK, now that you have figured it out, tell me.:laughing:
The cyls are laid out the same way they will be mounted, one push and one pull, there shouldnt be any binding. I did change my mounting design. The way I first drawed it uo, both cyl where going to be on the same pin on the steering arm. I was afraid trying to get 180* turning radius I might end up with the boom flipping over the pivot point and trying to go the wrong way. Mounting both cyl on the same end and different sides of center, on a slightly larger circle, the cyl rod will never reach a straight line pull or push. My biggest concern now is whether the 1/2" plate I want to use for the steering arm will hold up.

 

[BukitCase]

As far as the mechanicals, sounds like you got a handle on it - my original (prior to actually THINKING :laughing concern was getting a hydraulic LOCK, because of the fact that a normal cylinder (without a center piston and a THROUGH rod) takes more flow to push than it does to pull, and gives less power on the pull - both of those because of the rod diameter displacing a fair portion of the piston area being acted on by hydraulic pressure -

But then the brain farts kicked in - I finally realized that, with two identical cylinders, SERIES would be the way to plumb them to do what you want -

Lets say, for simple math's sake, that those cylinders have a rod size that would take exactly TWICE as much flow to extend, as they would to retract - and what you need is for BOTH cylinders to move the EXACT same distance, but Cylinder A would be EXTENDING and Cylinder B would be RETRACTING - if you were to plumb both EXTEND ports to a control valve and both RETRACT ports to EACH OTHER, then moving the valve one direction would cause (for example) ONE gallon of fluid to enter the larger extend side of cylinder A, which would then EXPEL only a HALF gallon - but that half gallon would enter the LOWER volume side of cylinder B, which would move THAT cylinder exactly the same distance as cylinder A, because that pressure is on the smaller volume RETRACT side (smaller volume because of the rod displacing half of that sides volume).

Then, when you moved the valve to its OTHER position, the exact same thing would happen but in the opposite direction - so in the end, both cylinders would move the same distance when actuated, but the second one (relative to the pressure input at the time) would have HALF the power. Since they would BOTH be trying to move the same plate, as long as the linkage geometry on both cyls was identical, the two cylinders' POWER would just ADD.

So, you'd end up with 1-1/2 times the power you'd have with just ONE cylinder during its PUSH cycle, but the TWO cylinders would have the SAME 1.5x power EITHER direction.

Now that I've fully confused BOTH of us (and anybody ELSE foolish enough to read this far ) I'll shut up now :ashamed: ...Steve

 

[muddstopper]

:teacher: I am only going to give you a 95 grade because you had to stop and think about it.:laughing::laughing:

 

[BukitCase]

I'll GLADLY take the 95% - if for no other reason than it'll let me quit looking for that "magic proportioning valve" that doesn't exist on my hoe
:thumbsup::thumbsup: ...Steve

 

[muddstopper]

Got a couple more pic. I finally got around to making the steering arm. Pics show the arm on the axle with cyl in approx position as to how they will be mounted once the boom is assembled. I also got some good news on the control valves to make this mess work. I had found a 4spool solenoid control valve. This provided enough spools to work the dump hoist, the boom hoist and the steering cyl with a spare. since I a mounting this on the tounge of the trailer, I really wanted some out riggers to steady things up when winching and lifting. I called the guy with the solenoid valve and turns out he has a second set of 4 spool solenoid valves. I can take one section from one and end up with a 5 spool valve and a 3 spool valve I will find a use for on another project. I think I have another matched pair of cyl I can use for outriggers, if not my newest best buddy has some I can choose from. This does change my tower design for my boom, but I havent built it yet so, time to scrounge some more tube.