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:
Apr. 15, 2003
Filed:
Aug. 09, 2000
Applicant:
Inventor:
Katsumi Nagai, Aichi-ken, JP;
Assignee:
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho, Kariya, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B66F 9/24 ; G06F 1/500 ;
U.S. Cl.
CPC ...
B66F 9/24 ; G06F 1/500 ;
Abstract
A pressure sensor is set in a conduit connected to a cylinder tube, and a temperature sensor is disposed within a chamber. Detection signals of the pressure sensor and the temperature sensor are sent to a control circuit. A sonic speed of the ultrasonic wave is corrected by using a relational formula or a map that is indicative of the relationship of the temperature and pressure of hydraulic oil to the sonic speed and that is stored in the storage device. A distance from an ultrasonic wave sensor to a bottom surface of the piston is calculated based on the sonic speed and a measurement time length detected by the ultrasonic wave sensor.