what are breakout forces in Excavator? is there any limitatation on these forces for particular size of excavator?
Breakout forces vary between excavator classes and are found in the specifications. Yes there are limits, too much breakout force and you will damage the machine, for instance if I increase the breakout force on my small excavator I might blow hyd hoses, bend rams, break buckets/arm/boom, etc. Manufacturers set the breakout force so that it is suitable for that size machine. Breakout force is set via relief valves, in other words, even so my excavator hydraulic system is capable of more breakout force the relief valve opens to protect the machine.
In general terms it is the amount of force that the tips of the bucket teeth or leading edge of the cutting edge on the bucket can exert against the material you are trying to load. It is affected by the size of the bucket cylinder size, the hydraulic pressure applied, the geometry of the linkage that tilts the bucket and the length of the bucket.
breakout forces in excavators, this is very interesting to me, im buying an excavator soon for my farm, i was thinking of a hitachi ex60-5. i have big tree stumps to take out, stone walls to move and land drainage to do. im afraid maybe an ex60-5 maybe damaging herself or twisting something when taking out the tree stumps. thats whats putting me in the notion of an ex100 or 120-5. id like the ex60 though for fuel consumption and ease of moving around. will the breakout force of an ex60 stop the machine from damaging or twisting herself in heavy work.
hitachi i take the guess that providing you run manufacturers specs on hydraulic pressure the machine and as long as you are respectful of the machine it shouldn't be able to bend/break/damage itself
As long as you don't go cranking the relief valves up, the machine won't hurt itself unless abused over the long term. As far as farming, stump removal. A 100 would be the smallest I'd personally consider for stump removal.
Breakout force it the amount of force at the bucket that is produced when using the stick cylinder, pryout is the force at the tooth using the bucket cylinder. The bigger the machine, the bigger the cylinders, the more force it will have.
No excavator is incapable of damaging itself.
thank you for your responses.. i now understand the breakout forces. how can these breakout forces be calculated? does the type of soil come into consideration when we calculate the breakout forces for a particular type of excavator?
You pretty much have to look at the manufacturers specifications to find ouut the breakout forces of a machine, its not an easy calculation. Soil type doesn't affect what the brealout force is, but a machine with higher breakout will perform generally better in a harder digging situation.
That's why I threw in the abuse clause. In a perfect world everyone would have the perfect machine for every task, but they don't. So you see machines being used for something it wasn't designed (ie: a 315 cat in shotrock) which is what I would consider abuse, a good operator makes all the difference though I think.
how the breakout forces change in SAE and ISO. what is the difference in these two terms. is arm crowd force important consideration into design or we can just take into consideration the bucket breakout forces..