Komatsu PC300LC-8 Operation & Maintenance Manual page 213

OPERATION
MACHINE OPERATIONS AND CONTROLS
Operations Using Bucket Dropping Force
Do not use the dropping force of the machine for digging, or use the
dropping force of the bucket as s pickaxe, breaker, or pile driver.
This will drastically reduce the life of the machine.
Operations Using Bucket as Lever
Do not use the bucket to lever rocks out. If the back of the bucket
contacts the rock behind, the principle of the lever will bring
excessive force to bear on the machine or work equipment, and
there is danger that this may lead to breakage or damage of the
machine.
In such situations, use only the force of the arm and bucket to carry
out the digging operation. If any excessive force is brought to bear,
the safety valve in the hydraulic system automatically controls the
force within the specified range, and this prevents damage to the
machine.
Operations Using Machine Dropping Force
Do not use the dropping force of the machine for digging.
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