Impact Energy Transmission Through Tools - NPK PH1 Operator's Manual

IMPACT ENERGY TRANSMISSION THROUGH
TOOLS
A hydraulic hammer converts hydraulic power to kinetic energy. The kinetic energy is
delivered by the hammer piston to the tool as an impact force.
Unlike a slowly transmitted force, such as the force with which a hydraulic cylinder
extends, the impact force produced by the piston when it hits the tool is transmitted
through the interior of the tool as a compression stress wave until it reaches the rock,
concrete, or other material that the tool is about to break. The compression wave speed
is equal to the speed of sound through steel, i.e., approximately 15,000 ft/sec.
Therefore, if the tool is three feet long, the impact force reaches the object to be broken
1/5000 (0.0002) second after the piston hits the tool.
Impact force is transmitted as stress waves through the tool.
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