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:
Mar. 19, 1996
Filed:
Sep. 22, 1994
Terry A Stoychoff, Garner, IA (US);
Iowa Mold Tooling Company, Inc., Garner, IA (US);
Abstract
Roughness or jerkiness in a hydraulic swing circuit in an implement having a plurality of control circuits each having a work performing device (28), (30), (32) including a swing circuit having a hydraulic motor (32), which when under an aiding load may function as a pump, is avoided in a construction that includes a source (10) of hydraulic fluid under pressure and a plurality of control valves (22), (24), (26) for the circuits which are interconnected between the source (10) and the associated work performing device (28), (30), (32). The system includes a pair of hydraulic conduits (34), (36) extending from the control valve (26) for the swing circuit to the hydraulic motor (32). A pair of pilot operated, dual level pressure relief valves (56), (58) are connected oppositely across the conduits (34), (36) at a location between the control valve (26) for the swing circuit and the hydraulic motor (32). A pair of pilot operated check valves (48), (50) are provided, one in each of the conduits (34), (36) at a location between the control valve (26) for the swing circuit and the pressure relief valves (56), (58). Each of the check valves (48) and (50) is oriented in its associated conduit to allow flow from the control valve (26) for the swing circuit toward the hydraulic motor (32) but not the reverse except when receiving a pilot signal. The pilots (60), (62) of the relief valves are connected to the conduit (34), (36) whose pressure is relieved by the associated pressure relief valve (56), (58) and the pilots (52), (54) for each of the check valves (48), (50) are connected to the conduit (34), (36) in which the other check valve (48), (50) is located.