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:
Sep. 13, 1983
Filed:
Oct. 05, 1981
Kabushiki Kaisha Akashi Seisakusho, Tokyo, JP;
Abstract
A 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.