OPERATION
On flat material such as concrete runways, starting to break in the middle of the material may cause vibrations to be transmitted throughout the breaker and excavator because the material has no place to break to. Always try to start at a point which will permit the material to break out.
MAINTAIN DOWN PRESSURE
Maintaining hard contact with the surface of the material to be broken in addition to maintaining adequate “down force” is very important. Always keep “down pressure” or “down force” on the point of the breaker by lifting the wheels, tracks, or stabilizers slightly above the ground. This method takes the “slack” out of the bracket and boom pivots, and reduces the impact on the pivots in the boom.
The operator needs to be constantly aware of the amount of down pressure being applied and be able to adjust it if necessary. Not enough down pressure results in low production and accelerates wear and tear on the equip- ment. Too much down pressure may cause the breaker housing to violently crash into the broken material when
In any breaking job, the operator should make every ef- fort to “follow” the breaker with “down pressure” as the machine breaks farther into the material. The breaker should be stopped as soon as
BREAKING
The operator should note the sound of the blow when the breaker is running. With experience, the operator will be able to tell the difference between a good solid blow and a hollow sounding blow. A hollow blow means that solid blows are not occurring and breaker should be re- positioned.
Continuous tool penetration usually does not do much good. If the material does not break with
Many materials do not respond well to continued ham- mering in one place. The breaker tool should be repo- sitioned on the work each time the tool penetrates but does not crack the material.
Do not break continuously Do not break continuously in one place
in one place.
Figure 7. Breaking
CAUTION
Continuous penetration in the same area for lengthy periods will create excessive temperatures at the tip of the tool bit resulting in loss of temper (hardness) of the bit, mushrooming of the tip of the bit and may lead to failure of the bit.
Use a “scoring” method of breaking when cracking the material becomes difficult. This technique involves strik- ing the rock or concrete at several places along a line where you want the crack to occur. Most materials break sooner when struck several places along a line than when struck repeatedly in one location. On each line, the breaker tool should be continually repositioned. Practice determines the best length of time to stay in one spot (15–20 seconds) and how far to move the breaker tool.
12 ► MB656 User Manual
