View Full Version : Breakout force?
03-01-2005, 04:38 PM
OK, what is it?
From what I understand, Xing isn't even sure what it is, or just can't quite understand how the number is derived (from what I remember of a ROC thread)?
Why does every manufacturer list it if the "average Joe" operator doesn't know what it is? I understand that the bigger the number, the better it is, but past that, it's no good to me.... I've been running equipment for several years and still have yet to figure it out.
Any help/thoughts would be much appreciated!
The break out force is the amount of force the machine generates curling the bucket up (skid steers). Many factors come into play. On skid steers, the size of the bucket or more specifically the length of the lip plays a major part in the force a machine is able to generate. The longer the lip (the further the distance from the tilt cylinders to the end of the bucket) the less force that it can generate. What type of bucket is used to achieve the published numbers, I don't know. I would imagine the shortest lip bucket the machine can be equipped with. Other factors that influence it is mounting geometery of the quick tach, mounting geometery of tilt cylinders and hydraulic pressure. My "theory" is this once the amount of breakout overcomes the amount of force needed to pull the rear of the machine off of the ground, you have reached a point of diminished return on breakout.
On excavators it is the same only with the curling power of the digging bucket. When adding most quick couplers and different buckets, the breakout force is altered from advertised ratings. Most excavator buckets come with several pin positions. Typically one will give a higher degree of range of motion while the other maximizes breakout. Measuring the bottom lip of the bucket to the top of the bucket is an indication of the amount of break out you will lose or gain. Usually it is lost. I would imagine the bucket used to produce advertised ratings would be a smaller capacity bucket to maximize the rating. The same principle applys as in skid steers the greater the distance from the lip to articulation point the greater the loss of break out. Hope this helps.
03-02-2005, 07:49 AM
Thanks ksss! I wasn't aware that this actually posted, I got a message that the server was too busy right after I tried to post it....
I figured it had something to do with that, but hadn't figured it out all the way yet.
03-02-2005, 03:52 PM
It's still hazy to me. I know the definition of breakout force, but I have trouble believing that one manufacturer (and only one) posts a breakout force of over 11,000 pounds. While this is very impressive, it begs the questions
1) Why is it so high;
2) Why haven't ANY other manufacturers been able to match this figure;
3) Does this manufacturer use a different means to measure breakout force;
4) The actual significance to an operator who is using this machine;
5) Can the machine dig without raising its rear into the air.
Without doubt, I can be wrong.
In any case, I'll *try* to get a copy of the exact definition. A paraphrased version is:
" 'Breakout foce,' pounds (and kilonewtons or kilograms) -- the maximum sustained vertical upward force exerted 100 mm (4") behind the tip of the bucket cutting edge and achieved through the ability to lift and/or rollback about the specified pivot point under the follow conditions:
a) Loader on a hard level surface with transmission in neutral;
b) All brakes released;
c) Unit at standard operating weight -- rear of loader not tied down
d) Bottom of cutting edge parallel to and not more than 20 mm (0.75") above or below the ground line.
e) When bucket sircuit is used the pivot point must be specified as the bucket hinge pin, and the unit blocked under the bucket hing pin pivot point in order to minimize linkage movement.
f) When the lift circuit is used, the pivot point much be specified as th elift arm hinge pin. Wheel loaders shall have front axle blocked to eliminate change in position of pivot pins due to tire deflection.
g) If both circuits are used simultaneously, the dominating pivot point listed in e) or f) must be specified.
h) If the circuit used causes the rear of the vehicle to leave the ground, then the vertical force value required to raise the rear of the vehicle is the breakout force.
i) for irregular shaped buckets, the tip of the bucket cutting edge referred to above shall mean the farther forward point of the cutting edge."
(If someone from SAE finds this to be in violation of copyright, you may delete this post. I did *not* take that excerpt from the SAE Handbook, however.)
03-02-2005, 03:59 PM
xing and ksss's definitions seem to differ a little. Ksss states it is simply the rollback force generated by the bucket, while Xing states it is the entire force that could be exerted with the bucket, dipper and boom pulling upward (I think that is what he is saying). As explained to me by Bobcat dealer, it is as Xing describes. Although my dealer and I could be wrong, and ksss correct.
Dan, I think it is important spec, depending on what you are doing with your machine. Demolition or stumping, you'd be wanting a high breakout force. Your typical digging or trenching, it might not be so important.
I know if you stumping without enough breakout force, it can be a very frustrating process. :cry:
03-02-2005, 05:41 PM
Mmm, I think the definition is a bit weird like that. The definition I posted was for skid steers only. Manufacturers can post up to two figures: lift breakout and bucket breakout. (And they're supposed to report which figure they're using. Some don't do that. Generally, it's the bucket breakout, then, that is reported. Certain manufacturers might actually add the two... I'll have to look in to that.) In reality, most operators use a combination of the two. In any case, ksss is saying that the force is the force required to roll the bucket back -- which is what the definition *implies*. Two notes:
1) you may have found where a manufacturer tweaks its information -- the force directed upward is only one component of the force; if manufacturers interpret this differently, then one could actually publish the resultant of the force (GREATER than the direct-vertical force);
2) the pivot point is the effect of "rollback," which is what kaiser is referring to. As the bucket is rotated back, the pivot point is the hinge pin. If the lift circuit is being used, the point is on the loader arms (different for vertical/radial machines).
In basic terminology, kaiser's and my posts are the same. How they are interpreted, however, may be how manufacturers can get around the otherwise seemingly precise guidelines.
If a manufacturer is using both the machines bucket roll back force and the machines lifting ability to formulate a breakout number than it doesn't surprise me that someone could come up with an 11,000 pound breakout. On a 95XT the lift capacity static is about 6300 (without counter weight) add to that the bucket break out which is about 6200 you have a total break out of 12,500. How a skid steer could generate 11000 with strictly its tilt cylinders is beyond me. However, as said it should be posted how that number is achieved. The fact that no one is anywhere near the 11000 rating of the Deere (Gehl is also very high) it leads me to believe the number is misleading. The breaker industry recently went through a similiar issue with different manufacturers rating their hammers differently making comparisons difficult if not impossible. Combined with the fact that no one was monitoring the testing process to be sure the numbers were properly attained.
03-04-2005, 10:31 AM
SAE has specific definitions for wheel and track loader breakout forces. SAE J732 is written for larger wheel and track loaders, but should also apply to skid steers and compact track loaders. Breakout force is one of the specifications defined, and here is how it is measured;
1. Loader on hard surface, transmission in neutral
2. All brakes released
3. Unit at standard operating weight, rear of loader not tied down
4. Bottom of cutting edge parallel to ground, no more than .75" above the ground
5. If tilt circuit is used, bucket hinge pin must be specified as pivot point, and lift arms should be blocked under bucked hinge pin to minimize linkage movement.
6. If lift circuit is used, piviot point should be specified as lift arm hinge pin, and front axle should be blocked to minimize tire deflection.
7. If both circiuts are used, the dominating piviot point must be specified.
8. If the cicuit causes the rear of the machine to leave the ground, the force required to lift the rear of the machine is the breakout force.
This is all listed in the Caterpillar Performace Handbook in the wheel loaders section. In the skid steer section, both lift and tilt breakout forces are listed separatly. Hopfully this sheds some light on the process for you.
Keep in mind that some manufacturers bend the rules from time to time to gain an advantage on paper. I'll leave out names, but I KNOW certain manufacturers bend the rules on horsepower, tipping load, and yes breakout force. Your job is to sort through the specs and get a general idea of what size machine will work for your operation, then try it out. Don't rely on paper. Some machines will do more than what is on paper, several will do less. A demo on your jobsite is always the best way to decide on a machine.
03-04-2005, 01:23 PM
Do you know if manufacturers add the tilt and lift breakout to get the published breakout force for articulated wheel loaders? Or how they derive that number?
03-04-2005, 01:46 PM
For wheel loaders, my product of course, they are considered two different specs. Tilt breakout is commonly referred to as "breakout force" and lift breakout is commonly referred to as "Static Tipping Load" Usually tilt breakout is not enough to lift the rear of the machine off the ground, due to basic geometry. Our new 930G has about 30,000 lbs of tilt breakout but will not lift the rear end with with bucket alone. Simple statics calculation. It also has about 18,000 lbs plus of Full Turn Static Tipping Load, which is more than enough to lift the rear of the machine. Again, simple statics calculation.
For wheel loaders, the two are never combined on paper. In the seat, you use both of them together (as long as the machine has load sensing hydraulics - save that for another conversation) to get your digging power. Both specs on the 930G are pretty high for its size, making it an incredibly strong feeling machine. That's why I encourage people to try a machine, not rely on paper specs.
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