Boom emergency lowering device of excavator

摘要

When the engine driving is stopped, the boom located at a certain height from the ground can be lowered to the emergency by utilizing the operating pressure of the hydraulic cylinder for driving the boom when descending to the ground to secure the safety of the equipment.;According to a preferred embodiment, an engine, a first hydraulic pump and a second hydraulic pump connected to and driven by the engine, and a boom driving hydraulic cylinder connected to the first hydraulic pump to rotate the boom within a predetermined stroke when driven. And a direction control valve installed between the first hydraulic pump and the boom driving hydraulic cylinder and controlling the flow direction of the hydraulic oil discharged from the first hydraulic pump when driven by the pilot signal pressure supply from the second hydraulic pump. And a pilot valve installed between the second hydraulic pump and the directional control valve to control the pilot signal pressure for driving the directional control valve during operation, and installed between the pilot valve and the boom driving hydraulic cylinder to stop the engine driving. When operating the directional control valve at the operating pressure of the hydraulic cylinder for the boom drive by the contraction of the hydraulic cylinder for the boom drive It provides an boom emergency lowering device of the excavator, characterized in that it is provided with an operation means for lowering the boom relative to the ground.;As a result, when the engine driving is stopped and the boom located at a certain height from the ground is lowered to the ground to secure the safety of the equipment, the process of accumulating energy by utilizing the operating pressure of the hydraulic cylinder for driving the boom is unnecessary. It has one advantage to prevent waste of energy.