Stanley Black & Decker MB656 user manual Maintain Down Pressure, Breaking

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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 “break-through” occurs.

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 “break-through” occurs or if it is apparent that good solid blows are not occurring.

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 3–6 inches of tool penetration, it usually won’t break with full penetra- tion. The time used for additional penetration could be better used to strike blows in another place.

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.

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Contents MB656 Declaration of Conformity Weisbeck, AndyTable of Contents Safety Symbols Local Safety RegulationsSafety Precautions Obey Safety Rules Be Thoroughly Trained Before Operating the Unit AloneKnow the Work Conditions Parking Brake 66219 Guaranteed Sound Power Level Sticker Tool Stickers & TagsPRE-INSTALLATION Instructions PRE-OPERATION ProceduresOperation Operating a Breaker Long Term StoragePreparation for USE Positioning the CarrierPositioning the Breaker Tool on the Work Material BackhoesMaintain Down Pressure BreakingBlank Firing Underwater Usage Grease the BITTroubleshooting Problem Cause SolutionMaintenance Daily Maintenance ChecksTool Stop and Lower Bushing Charging the Accumulator NormalFlow Control KIT Instructions Hose RoutingsWear Tolerances Lower Bushing ItemTool Stop Item Retainer PIN ItemTool Failure not Covered Under Warranty WORN-OUT Front Bushings or Retainer PinsProper USE & Care of Tool Bits Blank Firing or Free RunningPrying CorrosionTool Failure Covered Under Warranty Internal Material FlawMoil ChiselBlunt Flow Test Procedures Test ProcedureTroubleshooting Heat Load TestDefinitions ToolSpecifications Dimensions and WeightsAccessories MiscellaneousMB656 Power Cell Illustration Housing Parts Illustration MB656 Parts List Charge Valve Assy InclMB656 Mounting Brackets Page Stanley Hydraulic Tools SE Naef Road Milwaukie, Oregon