Add More Bucket Curl to Jinma 284

[Eagleview]

Oh, and you made a good observation about the bucket having a pie shaped slice out of it plus the stops. That would work too.
Just goes to show you there are several solutions, just have to identify the problems first...

Its always easy for someone else after studying a problem and looking at what has been already done to come up with an alternative . It's the man that makes the decision to make the first cut and get on with the job that deserves the accolades . The factory is going to have to rectify this problem , maybe it is a cheaper alternative for them to modify the design of the bucket and also recall the buckets of tractors in use for modification or replacement . They would be silly to not do anything about it as not only is it annoying and damaging to have them like that , it could also be dangerous . And if someone was to get hurt by say , a rock rolling out of the bucket onto their leg the litagation would be considerable .

 

[3RRL]

Iron Horse,
I do hope they correct that particular problem. I was under the impression that a couple other guys noticed the same on their 284's.

Tom,
I hear what you're saying about the cylinder's extra travel. I was guessing it might be to aid in lining up the mounting holes, so they don't have to be bang on? Or maybe to be sure there was always available pressure on either end. That pipe on your machine, is it there to limit travel or take a side load of some kind? Is the cylinder fixed at one end or does it have a pivoting mount? What is the cylinder pulling or pushing?

In my experience, cylinders should be designed so that the load on it is only linear ... whether in extension or compression. That is, the load is directly in line with the cylinder itself to keep the rod from bending no matter how far it's extended. That's why most are pivoting on both mounting ends for tractor use like FEL or grapples. If there is a side load imposed on it, then the cylinder mounting is incorrect IMHO. The mounting should always allow for a straight line to the load, like if you had a rope attached from the mount to the load. No matter how much you pulled on it or extended it, it should keep a straight line. If it bends or kinks over something, that is not good.

 

[tommu56]

Rob I'll try and attach a dwg of what I mean

tom

 

[3RRL]

Tom,
I see what you mean by that drawing. lol ... you are always one step ahead of me.
All I was trying to say was if the cylinder pivots at the right connecting pivot on your drawing, the whole cylinder body (should) point to the new location of the rod end (the green rod pivot) in a straight line.
No doubt though that the longer the rod is sticking out there, the more prone it is to bending.

 

[tommu56]

Rob
The only way I noticed that problem we had some rod end bearings wear and we weren't replacing them just seals so we were going through seals every 2 - 3 weeks I finally got involved and watched the machine and saw 2" cylinder pop about 1/2" to one side as the damper hit the seal (this damper is 90"in diameter double bladed so we don't loose any fumes) I had to call Miller cylinder rep in to see what was wrong he took one look and asked if we changed the rod end bearing and we said what was that (I wasn't in to hydraulics yet) and the rest was history.

tom

 

[SPIKER]

nice change there, I have older 284 with zl20 fel as well it has bucket problems that it does not tilt back far enough when down either. for some reason I think it was built that way so you can't over load the bucket with wet gravel and damage something... I never fixed mine but was going to.
Mark M

 

[NSTractor guy]

Hi Iron horse,

I was just curious about your excavator! Didn't you say before that you had a mini yuchai one with no problems, now this one is crappy? What is the differences? I am asking because I was thinking about getting one, a small one.

I assume that was a good price for that size machine.

Thanks for the info.

The geometry was all wrong , a kid could have designed it better . I too have bought some Chinese equipment because of it's price . The fit and finish and paintwork are terrible but you put up with that because it's cheap and it's only a work machine . Ive just paid $180,000 for a 23 tonne Chinese excavator , it's got all the good bits , Cummins motor , Kawasaki pumps and valves and Hydash final drives but no thought has gone into if all this stuff will work together in this package . Believe me , it does'nt . It's the biggest piece of crap that ive had the misfortune of owning , i'm currently spending a lot of money trying to make it do what it was supposed to do in the first place , i do'nt even want to think about the downtime . Next time i'll spend the extra and buy a quality machine that works for me instead of me working for it .

 

[Eagleview]

Hi Iron horse,

I was just curious about your excavator! Didn't you say before that you had a mini yuchai one with no problems, now this one is crappy? What is the differences? I am asking because I was thinking about getting one, a small one.

I assume that was a good price for that size machine.

Thanks for the info.

Up until yesterday i was very disapointed with the machine . It has been under powered since day one . Ive complained bitterly to the factory , they sent out an engineer to have a look . I showed him it would not push over a small tree or dig in hard ground . He said "not for push tree , not for dig hard dirt , must break with hammer first" He then said machine was fine and left . I parked it and walked away from it hoping the kids would burn it . Yesterday , the new importer of the machines heard i was very unhappy and the boss came down from Brisbane to drive it himself , he also bought 2 engineers from Singapore that where her completing the dealer hand over . The boss got in my machine and put it through its paces , got off shaking his head and said to the Chinese that if he was paying me to do work for him he would tell me to pack my bags and take that thing with me . He then said to the Chinese , fix it .... They spent an hour adjusting all the relief valve settings and now it digs like it should have in the first place , it's perfect . It's all they should have done in the first place and i would have been happy . Now i'm going to have a battle to get back on my feet , with what it's cost me in payments and downtime . But at least it's performing as it should and i can now tender some work with it . If your thinking of buying a Yuchai , they are a good machine but i would suggest you get one with steel tracks and rubber road pads rather than getting the Bridgestone rubber tracks . The inner drive cog on the rubber tracks fills with loose dirt which the sprocket gets on top of and the tracks come off . Also if you can get one without the swing boom , do so as its a pain . Because swing booms are front mounted they have too much purchase over the machine making the machine tip forward and make it very bouncy making final trim very difficult .

 

[3RRL]

Well, everything worked except I didn't get the amount of curl I wanted.
So back to the drawing board. I was afraid of that ... that I had spaced the holes too far apart in my first attempt. It gave me a tremendous mechanical advantage in the curl, but the dump was not nearly what I wanted.

I had to saw off the woody woodpecker tops first so the hand held bandsaw had enough room in the throat to make the next cut where the welds are. What a pain. Then I cut that part off too, right through the weld. Then I took them up to the barn to saw again so they looked like diamond shapes and would fit the way I wanted, placing the holes where they should be.

 

[3RRL]

This time, I figured to place the top hole very close to the original position. In fact, it is only 1" higher than original but 3/4" closer to the bucket than before. This move still allows a full dump but in placing the connection higher, The cylinder rod just misses the FEL arm at full extension. After seeing what the rod looked like during the initial inspection made that AS important as getting more curl ... and keeping a good deal of dump.

The move closer to the bucket is to allow for the added curl. That position gets the rear of the QA to touch the upper torque tube because it interfered on the stock QA plates and here you can see it now comes to the edge of the tube. This amount of curl also lets the lower torque tube hit the fel arms...together, they are now a natural stops for the curl. I will show you that later though.
Here you can see that I tried to make sure the new, new location would also clear for the hooks on the back of the bucket. I used my finger to see how much clearance there was.
Then I tack welded the pieces in position to see how they fit and worked. Note that I am still shooting for about 1" of stroke left to suck the cylinders completely in, and thus to curl completely back to the stops. What I did was measure from the top of the cylinder mount bushing (outside of it) to the edge of the cylinder body. I made that 1-1/2". That's why I say there's about 1" of cylinder stroke left sucking it in.
lol ... Amazingly, I had managed to save the holes AND the timing stops for the pins!