US Patent 9598839 Construction equipment

Disclosed is a construction equipment including: a boom operating unit including a boom, a boom cylinder, and a boom head and rod return solenoids for controlling the extension of the boom by controlling the ascending and descending of the boom cylinder; an arm operating unit comprising an arm and an arm cylinder so as to move the arm by controlling the extension of the arm cylinder; and a control unit for generating a flow path connection signal in at least a part of the boom head and rod return solenoids upon operation of an arm lever in a boom float mode so as to control the boom cylinder.