Hydraulic vibration tester
Patent 4403511 Issued on September 13, 1983. Estimated Expiration Date: 
October 5, 2001. 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.
October 5, 2001. 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 2773482 2865173 InventorsAssigneeApplicationNo. 06/308478 filed on 10/05/1981US Classes:73/665Having fluid bearing or fluid pressure actuatedExaminersPrimary: Ciarlante, Anthony V.Attorney, Agent or FirmInternational ClassesG01N 3/32 (20060101)G01N 3/36 (20060101) Foreign Application Priority Data1979-04-13 JPAbstractA hydraulic vibration tester comprises an actuator comprising a piston reciprocable in a cylinder connected with a vibration testing table and a direct drive type servo valve for supplying pressure fluid alternately to opposite ends of the cylinder. The servo valve comprises a spool valve member reciprocable in the bore of a valve body by a magnetic coil supplied with alternating current and located in a direct current magnetic field. At opposite ends of the spool valve member there are coned disc springs acting to bias the spool valve member to a median position and acting to allow only an axial reciprocating movement of the spool valve member at a frequency in the range of 650 Hz to 2000 Hz. The passages connecting the servo valve with the activator have a resonant frequency in the same range so as to achieve an effective vibration test in the high frequency range.Field of SearchHaving fluid bearing or fluid pressure actuated | |
