Method for coupling of a casing tube to a drill bit

Abstract

A method for connecting a casing tube to a drill bit. An annular groove is formed around an outer track of the bit. A drill shoe is utilized to connect the casing tube to the bit at a front edge of the bit. The connection ring is attached to the groove and the casing tube. If the connection ring is attached to the casing tube, at a first stage of the installation a chopped ring element is at least partially installed into the groove. At a second stage of the installation, the connection ring is pushed such that the ring element becomes strained simultaneously with moving into the groove, in which case when the connection ring is moved, the ring element moves in the groove and slides into the groove such that movement of the ring element to a deepest point of the groove is prohibited by a stopper.

1 . A method for connecting a casing tube to a drill bit, the method comprising:
 forming at an outer track of the bit an annular groove that circulates around the outer track;   utilizing a drill shoe to connect the casing tube to the bit at a front edge of the bit, wherein the drill shoe can be installed around the bit, and wherein the connection ring is attached both to the annular groove and to the casing tube in which case at the first stage of the installation either   a chopped ring element is installed into the groove located at the outer track of the bit at least partly or   the connection ring is installed on top of the ring bit to the destination point, and   wherein at a second stage of the installation   the connection ring is pushed around the bit so far that the ring element in the groove becomes strained at the same time into the groove existing at the inner surface of the connection ring in which case when the connection ring is being moved, the ring element follows in the groove along the connection ring and slides in the groove of the bit such that movement of the ring elements to the deepest point of the groove is prohibited by adding a stopper to the structure, wherein the stopper restricts the movement of the connection ring or   the ring element is installed into the groove of the bit when the connection ring is drawn back on top of the bit in front of the bit at least partly away from the location of the groove after which the connection ring is moved on top of the bit backwards and a locking piece is welded to restrict the axial movement of the connection ring.   
     
     
         2 . The method according to  claim 1 , wherein a ring that becomes strained outwards from the groove towards a larger diameter measurement is used as a ring element. 
     
     
         3 . The method according to  claim 1 , further comprising:
 forming a flat base part into the groove on the surface of the bit covering a distance that is allowed to be the axial movement of the connection ring and the ring element.   
     
     
         4 . The method according to  claim 3 , further comprising:
 welding stoppers to their locations during installation.