Title:
締付け工具
Document Type and Number:
Japanese Patent JP4093145
Kind Code:
B2
Abstract:
In a power impact tool for fastening a screw or a bolt, malfunction that driving of a motor (1) is stopped before the screw or the bolt is fastened completely can be prevented. A fastening judger (21) 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 (4) 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 (4) 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.
Inventors:
Koi Kawai
Yoshinori Sainomoto
Yoshinori Sainomoto
Application Number:
JP2003301899A
Publication Date:
June 04, 2008
Filing Date:
August 26, 2003
Export Citation:
Assignee:
MATSUSHITA ELECTRIC WORKS,LTD.
International Classes:
B25B23/151; B23P19/06; B25B21/02; B25B23/14; B25B23/145; B25B23/147
Domestic Patent References:
| JP2002283248A | ||||
| JP7256566A | ||||
| JP6119573A | ||||
| JP63150167A | ||||
| JP6352976A |
Attorney, Agent or Firm:
Keisei Nishikawa
Atsuo Mori
Atsuo Mori