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:
Aug. 23, 2005
Filed:
Apr. 08, 2003
Takashi Sakai, Tokyo, JP;
Minoru Kaneko, Tokyo, JP;
Takashi Sakai, Tokyo, JP;
Minoru Kaneko, Tokyo, JP;
Akebono Brake Industry Co., Ltd., Tokyo, JP;
Abstract
A sine wave electric signal whose frequency continuously varies within a predetermined frequency range is applied to a piezoelectric speaker, whereby a vibration frequency characteristic of the piezoelectric speaker is detected. A change of the frequency characteristic of the piezoelectric speaker when the piezoelectric speaker is brought into contact with concrete filled into a precast concrete form is detected based on the vibration frequency characteristic detected. With this unique feature, a filling status of concrete in the precast concrete form can exactly be detected independently of the hardness of water contained in the concrete and ambient temperature, and even if a temperature difference between air and the concrete is small.