ROCK BREAKING DEVICE

PURPOSE:To make it easy to insert power elements deeply into a holed portion so as to strengthen the ability of the power elements to break rock by connecting the power elements in series to each other via a flexible joint, the power elements each comprising thrust members, a rubber tube and wedges. CONSTITUTION:Power elements 1A, 1B connected in series via a flexible joint 2 each comprise two thrust members 7 of circular cross section arranged opposite to each other in cylindrical shape, a rubber tube 8 axially disposed in an inside hollow portion, hydraulic piping 17 connected to the tube 8, and two wedges 9. The power elements connected together are inserted into the holed portion of a rock bed and hydraulic oil is fed into the rubber tube, and then the thrust members are expanded to generate cracks in the rock bed, and the flexible joint is curved to help the power elements invade deeply into the holed portion. Thus it is facilitated to insert the power elements deeply into the holed portion.