Has anyone replaced a counterweight with a lighter one. I have a Kobelco SK 210 - 8 that is just a bit to heavy for my hauling configuration. I am not concerned about craning or how the machine will respond as I have had a 150 class excavator for many years and if anyone has ran that size machine you will know how they react to being a bit tippy over the side because of the narrower gauge. Anyways I would like to shave off about 5000 lbs of the 10000 lb counterweight. anyone have experience cutting down the counterweight or I might find a counterweight off a smaller machine and mod it to fit. Thanks Seedhay
I'd be interested to see how that turned out. I think I would rig a light counterweight to try before I put much effort into it. I expect you will be disappointed, I think a 210 with half a counterweight will not feel near as good as a 150
Just a thought, but it seems to me the two words "lighter counterweight" is a contradiction. There's a reason that weight on the rear of the machine is called a "counter" weight. Like Mitch said, you could remove the original counterweight and hang some sand bags off of the rear of the machine, but I doubt you'd be happy with the modification.
Lighter counterweight will put more stress on the swing bearing too.
Actually if you think about it, that's not really true. First you remove weight which is lightening the downforce on the bearing, and they're set up to be heavy on the ass to start with because you will be adding weight to the front when you dig. You won't be able to lift as much before the tracks come off the ground so again, the load should be lighter. When you hang a long stick, or a heavy attachment like a mulcher off the front, then add counterweight.. that stresses the bearing a lot. Just my way of thinking. When they mount excavator uppers on pontoons/swamp tracks they remove the entire counterweight usually.
When the tracks come off the ground there's less stress on the swing bearing, but when the operator keeps the tracks on the ground there is going to be more leverage on bearing without the counterweight back there. Shock loads will probably be more severe as well. So normal to heavy digging will be harder on the swing bearing, which i think will have a larger effect than lifting the tracks being less stressful than otherwise. Hope that makes sense. I probably shouldn't be thinking about physics right now.
I have enough barley soda in me right about now that I can say the same thing. I think both you and lantraxo have notable points, and I'm certainly no expert in mechanical engineering, but concerning slew ring bearings, keep in mind that many applications don't even use a counterweight such as a boom truck crane and a digger derrick, all the work load is being applied to the slew ring bearing in these applications. I think in reality the slew ring bearing is a very capable and strong component in a rotating machine, and that by design. As for the counterweight, and I get this bias from being an old crane operator, I think the counterweight plays a bigger role in lifting capacity than mitigating stress on the slew ring bearing. Just my opinion and nothing more.
Thanks Everyone for their input. I appreciate it. In my mind if you pull the boom, dipper and bucket in tight, this would make the unit tail heavy but because there is no loading or real forces in play does not affect anything. If your working in a slope and want to swing uphill with a full bucket you generally have to crowd in tight in order for the counter weight to take effect and counter balance the heavy bucket. what I'm trying to illustrate is that many times a day the unit can be in and out of balance. Although I do not like or want to try this light configuration I'm looking for alternatives to trading the unit off on a 160 class machine which I have ran for the last 20 years and as I may have mentioned before can be quite tippy over the side with full C/U bucket of material. So that is the sort of spec that this 210 will be working into or should I say pretty easy work and because of the extra long footprint front to back that the tracks have on the ground I'm not worried about being to tippy ( over the side I'm used to that already ). On another note I talked to someone quite knowledgeable and he was more concerned with the logic unit that does the sensing for hydraulics and such and he felt there would be confusion in the computer re the balance of the machine. As I said before. Thanks for the input Seedhay
I doubt the computer will be affected at all, it works on pressures I should think. There's not normally any angle sensors or load cells anywhere on those machines.
Kobelco had the demountable counterweight on the 500 excavator. http://www.heavyequipmentguide.ca/a...tem-for-sk500-model-excavator-at-conexpo-2014 There are quite a few excavator models from the various manufacturers that use a heavier base with the lighter upper body. (With safety rules in many places it can be better to get the wide base and lower total machine weight from the factory than modify your machine) -It depends what equipment you have available to you to demount and remount counterweight sections. If you are transporting the counterweights separately to the excavator. -Take the measurements of your existing counterweight and the measurements of your dipper stick. Look through the wrecking yards for counterweights that can be cut into sections (if you can't lift the counterweight whole) and mounted onto your machine. (Leave your own counterweight unaltered as it would likely impact on the tradein/ resale price of your machine. - If you cannot demount/remount then ask a mechanical engineer to calculate (there are excavator formulae) how much you might reduce the digger stick and how much you can reduce the counterweight, to bring the total machine weight down. It will likely reduce the reach of the excavator but you have a machine you will not have to take apart to transport & reassemble on arrival at a new site.
You will be really disappointed if you make the counterweight lighter the machine will be pretty much worthless especially if you have a quick coupler and thumb on it. Many of them we actually ADD counterweight to cause they are to light in the rear with couplers and big buckets. Try moving a machine with no counterweight on it some time and see what happens?
Cut your counterweight down, mount it on some extender rails with a pair of cylinders to push it out a couple feet, carry on. Just don't hit anything with it swinging. TANSTAAFL, right?
How many close mounted counter excavator weights do you see that do not have scuff marks or the paint worn off them from rubbing stuff? Excavator arms and sticks come in a variety of configurations. http://www.forconstructionpros.com/...s-and-sticks-for-maximum-excavator-production
Please, do these chaps and spurs look new to you? LOL.
What you can do is get a lighter counterweight and put it on the same distance as the heavy one. Or lenghten the brackets that hold the counterweight. Thats the way we usely adapt the counterweight. But normaly we put an extra slab of 6000kg or more in between so then the original counterweight sticks out 20cm or more out. Might give you a bit off both world in your situation. A lighter crane with the same(or as close as you can get) lifting and digging force. Sometimes an extra 15cm stick out will do the trick. And that is usely not even noticable when inside the cab. With a extra 6000kg counterslab we only gain 6000kg and 20cm usely. And this makes the cat 390 a lot more stabile.
So what exactly is the main problem, too heavy to haul on your current truck/trailer combo? To big to scale out right? Seems to me the easiest solution would be to get a heavier trailer or hire it moved, if you ran a 150 for that long it would appear to me that maybe you should have thought of the weight issue before buying this machine? I think you will probably find that machine darn near useless if you take 5k lbs worth of tail weight off.
Sometimes you need to back up and look at the overall picture... how's the ground where you work? Could you take off every other track shoe and still work? Might be close to the same thing by the time you're done. Don't laugh, just thinking outside the box, lol.