Step tube rod, and drilling machine

Abstract

In the present invention, in a drill rod for a boring machine, a rod outside diameter is large so as to be approximately equal to a bore diameter, external threads are provided at one end and internal threads are provided at the other end, and at least one small-diameter portion is formed near an internally threaded portion. This step tube rod can reduce a bore bend. Also, for the boring machine using this step tube rod, the drill rod can be positioned easily, so that the connection and recovery work can be performed efficiently and safely.

1 . A step tube rod characterized in that in a drill rod for a boring machine, a rod outside diameter is large so as to be approximately equal to a bore diameter, external threads are provided at one end and internal threads are provided at the other end, and at least one small-diameter portion is formed near an internally threaded portion.  
     
     
         2 . The step tube rod according to  claim 1 , characterized in that the small-diameter portion has an outside diameter which is 90% or less of the rod outside diameter and has a length which is 50% or more of the rod outside diameter.  
     
     
         3 . A step tube rod characterized in that in a drill rod for a boring machine, a rod outside diameter is large so as to be approximately equal to a bore diameter, external threads are provided at both ends so that the rods are connected via a sleeve, and at least one small-diameter portion is formed near an externally threaded portion.  
     
     
         4 . The step tube rod according to  claim 3 , characterized in that the small-diameter portion has an outside diameter which is 90% or less of the sleeve outside diameter and has a length which is 50% or more of the sleeve outside diameter.  
     
     
         5 . A boring machine characterized by using the step tube rod according to  claim 1 ,  2 ,  3  or  4  as a drill rod.  
     
     
         6 . The boring machine according to  claim 5 , characterized by using the step tube rod for a tip-end drill rod.