The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 27, 2026
Filed:
Apr. 02, 2025
Caterpillar Sarl, Geneva, CH;
Hideki Nakajima, Akashi, JP;
Koichi Kiyasu, Akashi, JP;
Caterpillar SARL, Geneva, CH;
Abstract
Problem to be solved: To provide a hydraulic circuit for a construction machine capable of supplying hydraulic oil to a closed circuit without a charge pump. Means for solving the problem: The open circuit of the hydraulic circuit includes a hydraulic pump, a hydraulic actuator operated by hydraulic oil discharged from the hydraulic pump, a directional switching valve for switching a flow direction of the hydraulic oil from the hydraulic pump to the hydraulic actuator, a return line connecting the directional switching valve and a hydraulic oil tank, and a return check valve provided in the return line. The closed circuit of the hydraulic circuit includes a bidirectional hydraulic pump having a first port and a second port, a hydraulic motor operated by hydraulic oil discharged from the bidirectional hydraulic pump, a first line connecting the first port of the bidirectional hydraulic pump and the hydraulic motor, and a second line connecting the second port of the bidirectional hydraulic pump and the hydraulic motor. Between the open circuit and the closed circuit, a charge line connecting the return line and the first line via a first check valve and connecting the return line and the second line via a second check valve is provided.