PURPOSE: To simplify a device by providing a plurality of fluid-pressure jacks provided with loading platforms on the front ends and charged with pressure gas in the upper parts of cylinders to a reaction force platform having high rigidity in a row so that they are capable of operating, and restoring a piston to the original position by pressure gas after fluid-pressure is released.
CONSTITUTION: A reaction force platform 1 is inserted into an excavated hole bored in a bedrock or concrete, etc., to be crushed, fluid pressure is supplied to each of jacks from a fluid-pressure pipe 7, and cracks are generated in the bedrock, etc., by a piston 2a having loading platforms 5 on the front end thereof. After that, after fluid-pressure is released, the piston 2a is restored to the original position by pressure-gas 8 charged to the upper part of a cylinder. A return pipe is not required except for a pressure-pipe. According to the constitution, construction of a device can be simplified.
SUEKI HIDEO
KADOTA SHUNICHI
MURAYAMA HIDEYUKI
NAGANO YUKI KK