Hydraulic hammers are based on the work of Blaise Pascal.
Hydraulic hammers are the modern descendants of pile drivers. Piles are mechanical devices used to drive piles into the ground to establish foundations for buildings. The advent of diesel, hydraulics, and pneumatics helped provide the power needed to drive piles into the ground and carry out larger construction projects.
Hydraulic devices like the hydraulic hammer are based on the theories of fluid mechanics and the work of Blaise Pascal and Daniel Bernoulli. A hydraulic system consists of fluid, pump, pipes, motor, and output device. Hydraulics provide motive power to activate machinery, converting pressure exerted on a confined liquid medium into a mechanical output. The pressure exerted on the enclosed incompressible liquid is transferred equally in all directions and areas of the hydraulic system and is transmitted unabated to the output device, which in this case is the hammer.
Pile drivers can trace their lineage back to hydraulic breakers.
According to Pascal’s law (P=F/A), applying a small force (F) to a small piston over a small area (A) creates a mechanical advantage when the resulting constant pressure (P) is redirected through tubes to a larger area, producing a larger force capable of moving a larger piston. This concept is illustrated in the following example:
Pascal’s Law: P = F/A
If F 1 = 2 pounds (1 kg), A 1 = 1 in 2 (6 cm 2 )
P = F1 / H1 = 2 lbs/in2 (0.1 kg/cm2)
If F2 = x, A2 = 1000 in2 (6452 cm2)
F 1 / A 1 = P = F 2 / A 2
F1/A1 = F2/A2
2 pounds/in2 = x/1000 in2
x = (2 lbs/in2) (1000 in2) = 2000 lbs (907 kg) = F2
Essentially, this boils down to a significant increase in power: what starts out as 2lbs (1kg) of force ends up being 2000lbs (907kg) when area is increased.
Concrete piles used in construction can be driven into the ground with pile hammers.
Hydraulic breakers have versatile applications in the construction, demolition, metal forging, quarrying and piling industries. As a pile driving device, hydraulic hammers drive piles into the ground by moving in cycles of forward and backward direction. Hammer travel stops while digging tool is raised and can drop freely. As soon as it reaches the surface, the hydraulic hammer resumes its journey to break the surface. Impact force is regulated by factors such as piston weight, piston stroke, operating pressure, flow rate, hammer weight and dimensions, power output, and guide tube and guide jaw dimensions.
Hydraulic breakers can be mounted on the end of a mobile boom and used to break up rock and concrete. They can be powered by a dedicated diesel engine or by the puller’s own diesel engine if mounted as a boom attachment. Various interchangeable hammer bits are available, such as asphalt cutter, moil point, sheet crimper, chisel point, tamper, ram, or blunt tool that can be equipped to customize the function of the device.
Hydraulic breakers are more environmentally friendly than other breakers because they generate less noise and pollutants. They are preferred in areas sensitive to vibration and noise, as the use of vibratory hammers can disturb the stability of existing structures or audibly disturb communities.