A Question about Hydraulics

BR-549

Joined Sep 22, 2013
4,928
"I find your comments to be completely off topic and insulting." Why?

"Did you understand my post?" I thought I did.

"Did you put any effort into actually trying to answer my question or contribute positively?" Yes and most sincerely.

Who said you were a slacker?

I am not anonymous. I'm Junior Sample, and I have a used car lot. Call BR-549.

I operated 2 draglines, 2 cats, 2 loaders, 1 large backhoe, 6, 10 wheel dump trucks, 2 transports, aux. equipment, and 6 men for a 6 year period. Although no experience is required to answer a post, I used mine to help you.

From your last post, it's easy to see that you have some personal emotional issues to resolve.

I apologize to you and I will not participate in any of your threads.

May your family have a very Merry Christmas and a very prosperous New Year.

BR-549
 

tcmtech

Joined Nov 4, 2013
2,867
I dont know about BR-549 but I've been running excavators for ~20 years and working with hydraulics systems even longer.

Even turned a old farm tractor into my own personal backhoe using mix and matched parts.
DCP02472.JPG

Even got so bold as to teach my wife to operate a mini excavator proficiently who is the same woman who refuses to learn anything no that takes skill matter how basic.
DSC09411.JPG

Then I even took my boldness right over the top so far as to get her going on my contraption of which she can now even hold a grade with.

DCP02494.JPG

I say practice.

(even my wife can do it and she usually won't do anything.):oops:
 

strantor

Joined Oct 3, 2010
6,782
LOL I drove a bobcat for the first time a couple of weeks ago. My friend in HS used to drive one loading feed sacks, hay bales, fence posts, etc at the place he worked; I always wanted to try it out but his boss watched like a hawk and I never got a chance. So my company rented one to repair the test yard where we set up the tools for testing and I hopped on. After about 10 minutes I figured out how to make the thing move; I dove it across the yard and back and that was enough for me to recognize that I was not the man for the job. Of course I could be, given time to practice, but the bean counters would say that's an inefficient usage of manpower. So the shop hands got to have all the fun.
 

Thread Starter

jpanhalt

Joined Jan 18, 2008
11,087
@stantor
I have a New Holland L175 skid steer that I got this past Summer. It is easy to drive, very powerful, smooth (only 600 hours), and all that. It is the one machine that scares me, and that is saying quite a bit, going back some 40 years. I have only 15 hours or so in it, as I got it at the end of Summer. I am hoping it is just the lack of visibility (it has the "super boom") and is configured a bit differently than a Bobcat. A friend let me drive his Bobcat (tracked) unit last year, before I bought the NH. I said, "You know, I feel safest when I am backing up, but I can't see anything." He agreed, and offered that that was why he always backed up any hill. They are very powerful machines. I adapted a snow plow to mine, but we haven't had any snow. The other thing is, I have been experimenting with various rear view camera set ups. I think I have something that makes backing into the barn a cinch.

I don't blame the "boss" for being nervous when you drove it. But, they are a lot of fun, aren't they?

John
 

WBahn

Joined Mar 31, 2012
29,976
Part of the problem you are going to have is that you have to take the machine kinematics into account and there may not always be a unique solution. Part of the kinematics is also how the machine is setting on the ground. Just consider the case where the machine is tipped, say, backward and to the right relative to the section you are trying to grade. The movements of the various booms is going to be different than if you were sitting on level ground. Also, you have to decide what motion you want in the first place -- a level movement from the tip of the bucket directly back toward the machine, or a level movement in parallel tracks (much harder to do, but more efficient timewise).
 

Thread Starter

jpanhalt

Joined Jan 18, 2008
11,087
Yes, it can be a complex 3D problem, but most commonly with these small machines, the bucket doesn't angle or rotate on a perpendicular axis. If the machine is not parallel left to right compared to the surface being worked, i.e., has roll relative to what you want to level, then the leveling is more difficult. One can use a side-to-side motion, as both the boom swings relative to the frame and whole frame swings relative to the tracks on small machines. That is not the problem I am dreaming about now.

As for the more common problem of a front to back tilt ("pitch"), I think that can be taken care of by "zeroing." I do that with the wireless leveler I made for pallet forks attached to a tractor loader. The tractor itself does not need to be level front to back for it to work.

There are three pivot points in addition to the rotary motions just described. The boom pivots at the excavator frame. At the end of the boom, the "dipper" ("stick") pivots, and the bucket pivots at the end of the dipper. Right now, I am just playing on paper with the boom and dipper pivoting and the bucket being fixed. In real life, the bucket will probably need to pivot when longer distances are involved. Obviously, the triangle formed by the end of the dipper, boom-dipper pivot, and boom- excavator-frame pivot is fully defined knowing the angle of the dipper to the boom. To that, I am adding "pitch," namely the angle of the boom to the excavator frame. In this simplified model, , ignoring the bucket, it is by adjustment of pitch that allows one to keep the drag level. The accelerometers (2 at present) simply substitute for goniometers at the pivot points.

In this early stage, I am thinking of the dipper being the independent input and the boom-frame pivot being the controlled variable. The dipper and bucket are on the right control, and the boom and swing are on the left control on my machine -- a very common arrangement in the US.

... or a level movement in parallel tracks (much harder to do, but more efficient timewise).
I am not exactly sure I understand what that phrase means. If you mean effectively offsetting the boom from the frame centerline, yes, that can be done by rotating the frame and boom in opposite directions. You can also set up with the tracks perpendicular to the boom and just go back and forth with the tracks. That is how I leveled an area in the barn last Summer for a concrete slab. I don't believe the former option is available on bigger machines -- at least it wasn't on the 16T machine we used for putting in a new culvert.

John
 

killivolt

Joined Jan 10, 2010
835
I have nothing I could add but a sidebar; I once took a "Heavy Equipment" Certification Class at a local "College" at the time I was 17. Note: The College is now a University. While I took this class it was ran by the Father of one of the students? So, no one actually was able to train on the equipment because "Dad / Teacher" only let son and his friends to be first in line. So, we all got the job of running the large fork lift; and we transferred the "Equipment Depot" to a new location. This to provide a Baseball field that would be built.

I did learn I didn't want this job anyway; regardless of lack of training. I just didn't want to be in the heat of the day with dust all around me. "First rip off of this College"

Still a "College" I came back to the college later; attending and got my Degree in Refrigeration and Air-Condition. However, during my second year we had to move to the new location because we we're on the old campus and I removed and reinstalled all the test equipment and yes once again there was a "Dad / Teacher" and a son and his friends who would train on those pieces as they were installed. I learned on the job in the end. Ok, what ever.

Lastly, as I tell this story to others at work. Now, employed by the same "College / University" I'm just getting the education for free (Benefit of working for a University / College) that I deserved back then.

Not only that, but the "Jerks" Annexed my Fathers first home which accommodated 3 apartments. For just pennies on the dollars and built the "College / University"

Seems I was born to work for them. Oh, ya I was born in that house. lol

John, Merry Christmas and Happy New Year.

kv

Edit: Sorry for the long story; but it brought back a few memories.
 
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Brownout

Joined Jan 10, 2012
2,390
I am thinking of the dipper being the independent input and the boom-frame pivot being the controlled variable.
This is what I was thinking, except both the dipper angle and boom angle would be inputs. You really need to have both in order to control the boom for a level pull. But your idea is correct, and compliant to the KISS principle.
 

Thread Starter

jpanhalt

Joined Jan 18, 2008
11,087
Thanks. I was not clear on what I meant. That is the direction I am thinking. Both dipper and boom inclinations would be inputs. I would control the dipper (and bucket) with my right hand. The boom would be controlled by the MCU with manual override. The controls are hydraulic. Komatsu calls it a PPC valve, but I am not sure at what pressure it operates.

John
 

Wendy

Joined Mar 24, 2008
23,415
That is too funny. They ought to put things in the cabs, since they are going to be time capsules anyhow.
 
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