Pilot operated stepping valve
Patent 4145956 Issued on March 27, 1979. Estimated Expiration Date: 
April 25, 1997. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
April 25, 1997. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2654347 3079899 3125002 3310284 3709257 3805670 3875849 3891145 InventorsAssigneeApplicationNo. 05/790772 filed on 04/25/1977US Classes:91/380, Screw and follower (e.g., nut, etc.)137/625.64, Electric91/461Pilot valve (304)ExaminersPrimary: Michalsky, Gerald A.Attorney, Agent or FirmInternational ClassesF15B 13/00 (20060101)F15B 13/043 (20060101) AbstractA pilot operated stepping valve where an electrical pulse motor drives a pilot valve spool which controls the flow of hydraulic fluid driving a main valve spool which actuates a hydraulic motor or actuator. The main valve spool follows the pilot spool and is hence sensitive to the pulses received by the pulse motor. | |
