| 摘要 |
A V-shaped frame 102 is attached to a pipe 100 to be drilled. The frame may be used with larger pipes by attaching a removable extension plates 120 to the arms 104 106 of the V-shaped frame, thereby increasing the size of the recess between the arms 104, 106 . The apparatus may be fixed to the pipe 100 by a chain 110 which connects to the platform 102 and extends around the pipe 100 , or by attaching clips to the frame and attaching the clips to the surface of the pipe by screws etc. To attach the apparatus to a pipe having a corrugated outer surface, clamp members 340 extend into the grooves 308 '' of the corrugations to grip the groove walls 316.
|
