| 摘要 |
<p>According to the present invention, disclosed is an auto three stage hydraulic braker using a pressure change in nitrogen gas to figure out the hardness of a crushed object; thus, reducing a measurement error in accordance with a vibration of a cylinder, the maintenance of a sensor being easy, and a stroke distance controlled by three stages to improve working efficiency depending on the hardness of the crushed object automatically or manually. To achieve this, the present invention relates to a hydraulic braker comprising: a cylinder body wherein a piston can be reciprocally moved; a front head interconnected to a first side of the cylinder body, wherein a chisel is mounted to be reciprocally moved; a back head filled with nitrogen gas in a second side of the cylinder body; a pressure sensing unit arranged to sense the pressure change caused by the reaction of the crushed object which the chisel crushes in the back head; and a stroke distance control unit setting the stroke distance of the piston based on a hardness table defined about a speed of pressure change calculated by referring a pressure change in the pressure sensing unit and the hardness of the crushed object.</p> |
