Gravity Compensation Device to Reduce Load in Downward Drilling Work

Drilling work with breakers, as seen in demolition work, must be performed manually in narrow spaces and on unstable scaffolding. However, since rock drilling by human power may cause musculoskeletal disorders, a device to reduce the burden is necessary. Toward this end, various studies and product development efforts have been made. However, due to the residual load caused by the weight of the breaker and the resistance force of the product, a device to make the breaker easier to handle is needed. In this study, we developed a gravity compensation device that incorporates spiral pulleys and springs to hold heavy objects at an arbitrary height. We then proposed a method to determine the shape of the spiral pulley based on the size of the equilibrium range in order to adapt the device to drilling work that requires up and down movement of a heavy object. Finally, through experiments, we showed that the proposed design method is capable of equilibrium movement across the design range and is effective at reducing the exerted force when handling heavy objects, thus confirming the effectiveness of the device.