ALEXANDRIA, Va., Feb. 12 -- United States Patent no. 12,221,763, issued on Feb. 11, was assigned to HITACHI CONSTRUCTION MACHINERY Co. LTD. (Tokyo).
"Hydraulic excavator" was invented by Teruki Igarashi (Tsuchiura, Japan), Akihiro Narazaki (Tsukuba, Japan) and Masamichi Itou (Toride, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "A hydraulic actuator includes a control valve unit that controls a flow of a hydraulic fluid supplied from a hydraulic pump to a plurality of hydraulic actuators, a plurality of control lever devices that output a pilot pressure actuating the control valve unit, with use of a discharged pressure from a pilot pump as a source pressure, a solenoid valve unit including a pluralit...