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:
Jun. 12, 1990
Filed:
Jul. 17, 1989
Mark S Stroze, Rockford, IL (US);
Shan-Chin Tsai, Rockford, IL (US);
Sundstrand Corporation, Rockford, IL (US);
Abstract
The problem of controlling overspeed and/or oscillation of a variable displacement hydromechanical actuation system is solved by a multi-stage flow regulating valve (18) which includes a valve body (20, 22) having a fluid inlet (24) and a fluid outlet (26) defining a flow path (A,B) through the valve body. A first stage valve piston (30) is reciprocally mounted within a cylinder (28) in the valve body (20) in the flow path between the inlet and the outlet for restricting fluid flow in response to a first range of incoming fluid pressure. The first stage piston (30) has an inlet orifice (34) exposed to the incoming fluid and an outlet port (36) in registry with the outlet (26) of the valve body (20). A second stage valve piston (44) is reciprocally mounted within the first stage piston (30) and has an orifice plate (46) for covering the inlet orifice (34) of the first stage valve piston (30). The orifice plate has smaller orifices (48) for further restricting fluid flow through the valve body. The first stage piston is loaded by a spring (38) defining a first range of incoming fluid pressure and the reference pressure on the second stage valve piston defines a second range of incoming fluid pressure to provide a distinct multi-level range of regulating pressures.