Bad vibrations

Sandvik's research department has been analysing the cause and effect ofwhole body vibration (WBV) in hydraulic hammer applications and has devised some techniques and methods to help reduce these effects.

The European health authorities have long been interested in continuous vibration as it can cause short and long term harm to the operator. A spokesman for Sandvik said the company's findings confirmed that the primary causes of vibration during hydraulic hammer duties are recoil of the piston when impacting the tool; recoil of the stress wave from the tool; penetration of the tool into the rock or concrete; collapse of boulders or concrete structures and the movement of the hammer around the site.

“The tests also proved that the main direction of vibration in hammer work applications is front to back,” the spokesman said.

Sandvik suggested solutions including: precise hydraulic timing and design to minimise piston recoil; total insulation with polymeric materials to almost totally eliminate the impact recoil and an addition of soft side pads to absorb front to back movement of the operator's cab, the spokesman added.

The smooth positioning of the hammer's tool on the target material and the application of the correct