Patent ID: 7942600

Claim:
A passage block coupling apparatus, including an upper-stage passage block having a downward opening and a lower-stage passage block having an upward opening which are coupled to each other such that the openings are made to mutually abut against each other, comprising: a bolt insertion hole and a pin insertion hole formed in the upper-stage passage block so as to sandwich the downward opening; a screw hole and a non-screw hole that are formed in the lower-stage passage block, respectively; a bolt that is insertable into the bolt insertion hole of the upper-stage passage block, and threaded with the screw hole of the lower-stage passage block; and a positioning pin that is insertable into the pin insertion hole of the upper-stage passage block, with a lower end portion thereof being fitted to the non-screw hole of the lower-stage passage block, wherein a cut-out section is formed near the lower end portion of the positioning pin, with a diameter of the non-screw hole being made larger than a diameter of the lower end portion of the positioning pin, and a protruding portion to be fitted to the cut-out section of the positioning pin is formed on the non-screw hole so that the cut-out section of the positioning pin and the protruding portion of the non-screw hole are fitted with each other prior to fastening of the bolt to the screwhole of the lower-stage passage block such that an evenly fastened state is achieved with the tightening force of the bolt and a pressing force, applied by the lower end portion of the positioning pin to the protruding portion of the non-screw hole upward, so that the passage blocks are mutually coupled with each other.