Title:
AXIAL TENSION MEASURING BOLT
Document Type and Number:
Japanese Patent JP3535295
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To measure axial tension accurately by forming a pin tail integrally at the tip of a bolt with a nut engaged, through a neck part, and forming an ultrasonic reflecting part in the head side position of a torchier type high tension bolt away from a neck part position.
SOLUTION: A head face 1A of a shear bolt 1 is cut so that an ultrasonic sensor 4 adheres closely to the head face 1A, and the ultrasonic sensor 4 is installed at the head face 1A of the bolt 1. Load is applied to the bolt 1 by a tension testing machine or the like, and the relation between the elongation of the bolt 1 and the ultrasonic propagation time difference before and after applying load is obtained and set as a material constant. The bolt 1 is set to fastened members 6A, 6B, and the ultrasonic propagation line of the bolt 1 before fastening is measured by an ultrasonic reflecting part 7 using reflected wave. The bolt 1 is then fastened by rotating a nut 5 by an exclusive power type thread fastening machine until a pin tail 3 is cut from a neck part 2, and ultrasonic propagation time after fastening is measured. Axial tension is computed from the compliance and the like of the bolt on the basis of the material constant and the propagation time difference before and after fastening. The axial tension of the bolt can thereby be measured correctly.
Inventors:
Iwasaki, Akihiko
Application Number:
JP317796A
Publication Date:
June 07, 2004
Filing Date:
January 11, 1996
Export Citation:
Assignee:
TONICHI SEISAKUSHO:KK
International Classes:
G01L5/00; F16B31/02; G01L5/24; (IPC1-7): F16B31/02; G01L5/24
Attorney, Agent or Firm:
岸田 正行 （外２名）