Drill Assembly

Abstract

Drill assembly for making a hole into a soil or rock which arrangement comprises a pilot bit ( 10 ) drilling the middle part of the hole and a ring bit ( 1 ) drilling the outer circle of the hole in which case in the drilling situation the ring bit ( 1 ) is adjusted around the pilot bit ( 10 ) and rotary movement and drilling impacts are directed from the pilot bit ( 10 ) to the ring bit ( 1 ) with the help of the mentioned surfaces ( 4 - 6 );( 7 - 9 ),( 15, 16 ) adjusted between the bits and conveying power and that the ring bit ( 1 ) can be removed around the pilot bit ( 10 ) and can be installed to it and that further a coupling ring ( 2 ) belongs around the ring bit ( 1 ) in order to join a casing pipe, which can be pulled to the drilled hole, to the ring bit ( 1 ) with the help of the mentioned coupling ring. The coupling ring. ( 2 ) is adjusted around the periphery of the ring bit ( 1 ) in such a way that of the parts ( 13 ) taking part in the locking of the coupling ring ( 2 ) at least two are located at the different sides of the line (L) when the arrangement is assembled which line runs essentially through the middle point of the surface ( 5 ) conveying the rotation of the ring bit ( 1 ).

1 . Drill assembly for making a hole into a soil or rock which assembly comprises a pilot bit ( 10 ) drilling the middle part of the hole and a ring bit ( 1 ) drilling the outer circle of the hole in which case in the drilling situation the ring bit ( 1 ) is adjusted around the pilot bit ( 10 ) and rotary movement and drilling impacts are directed from the pilot bit ( 10 ) to the ring bit ( 1 ) with the help of the mentioned surfaces ( 4 - 6 );( 7 - 9 );( 15 ,  16 ) adjusted between the bits and conveying power and that the ring bit ( 1 ) can be removed around the pilot bit ( 10 ) and can be installed to it and that further a coupling ring ( 2 ), which can be locked to the ring bit ( 1 ), belongs around the ring bit ( 1 ) in order to join a casing pipe, which can be pulled into the drilled hole, to the ring bit ( 1 ) with the help of the mentioned coupling ring, characterized in that the coupling ring ( 2 ) is adjusted around the periphery of the ring bit ( 1 ) in such a way that of the parts ( 13 ) taking part in the reciprocal locking of the coupling ring ( 2 ) and the ring bit ( 1 ) at least two are located at different sides of the line (L) when the arrangement is assembled which line runs essentially through the middle point of the surface ( 5 ) conveying the rotation of the ring bit ( 1 ). 
     
     
         2 . Drill assembly according to the  claim 1 , characterized in that the ring bit ( 1 ) comprises at least two annular grooves ( 12 ) at the outer circle in which annular grooves the parts taking part in the locking, like shoulder rings ( 13 ), and which are located at the inner surface of the coupling ring ( 2 ) are adjusted to rotate and move in a limited way in the axial direction of the drill. 
     
     
         3 . Drill assembly according to the  claim 1 , characterized in that the back part (periphery part) of the flange part ( 14 ) of the ring bit ( 1 ) comprises essentially only the counter forms ( 12 ) of the locking forms ( 13 ) of the coupling ring ( 2 ) and the counter forms ( 4   6 ); ( 5 ,  16 ,  17 ) of the locking forms ( 7 - 9 ) of the pilot bit ( 10 ). 
     
     
         4 . Drill assembly according to the  claim 1 , characterized in that the surfaces ( 4 - 6 );( 7 - 9 ); ( 5 ,  16 ) of the bits ( 1 ); ( 10 ) sometimes conveying force and impacts are essentially at that part of the cylinder part of the ring bit ( 1 ) which begins from the flange part ( 14 ) and ends to the trail edge of the ring bit ( 1 ). 
     
     
         5 . Drill assembly according to the  claim 1 , characterized in that the inner surface of the ring bit ( 1 ) is even without the forms which diverge from it towards the pilot bit ( 10 ). 
     
     
         6 . Drill assembly according to the  claim 1 , characterized in that the counter parts ( 4 - 6 ) of the locking forms ( 7 - 9 ) formed to the pilot bit ( 10 ) and located at the periphery part of the ring bit ( 1 ) are forms which are directed through the periphery part of the ring bit ( 1 ). 
     
     
         7 . Drill assembly according to the  claim 1 , characterized in that the counter forms ( 5 ,  16 ,  17 ) of the locking forms formed to the pilot bit ( 10 ) and located at the periphery part of the ring bit ( 1 ) are surfaces and grooves formed to the periphery part of the ring bit ( 1 ), to its inner surface which surfaces and grooves do not penetrate the wall of the periphery part. 
     
     
         8 . Drill assembly according to the  claim 1 , characterized in that the surface located at the periphery part of the ring bit ( 1 ) and receiving impacts from the pilot bit ( 10 ) is a surface with a lift ( 4 ).