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:
Dec. 27, 2005
Filed:
Aug. 25, 2004
Kozo Kawai, Neyagawa, JP;
Yoshinori Sainomoto, Sanda, JP;
Kozo Kawai, Neyagawa, JP;
Yoshinori Sainomoto, Sanda, JP;
Matsushita Electric Works, Ltd., Osaka, JP;
Abstract
In a power impact tool for fastening a screw or a bolt, malfunction that driving of a motor is stopped before the screw or the bolt is fastened completely can be prevented. A fastening judger judged that the fastening operation is completed at least when a torque variation ratio becomes substantially zero and a reference index becomes equal to or larger than a threshold value of trouble judgment. The reference index is a number of impact of a hammer in a term in which the torque variation ratios take positive values, and the threshold value of trouble judgment is calculated with using a maximum value of the torque variation ratio in the term. Since the number of the impact of the hammer due to trouble in fastening operation is smaller than that due to the screw or the bolt is fastened completely, it is possible to distinguish the increase of the torque in the former case from the increase of the torque in the latter case.