Grip head for an earth boring unit

Abstract

The invention relates to a grip head for an earth boring unit, comprising a hollow shaft ( 3 ), wherein a sleeve ( 1 ) is arranged coaxially on the hollow shaft ( 3 ) to slide relative thereto, said sleeve having at least one end region ( 1 b ) widening particularly at the bottom thereof particularly in the form of a cone and at least two clamp jaws ( 2 ) which can be displaced radially relative to the hollow shaft ( 3 ) are arranged in the hollow shaft ( 3 ) and/or on the sleeve ( 1 ), comprising stop faces ( 2 b ) cooperating with the widening end region ( 1 b ), such that on movement of the end region ( 1 b ) over the clamp jaws ( 2 ) said jaws may be pressed inwards and a first tensioning mechanism and form a first tensioning device for an upper end of a casing ( 9 ) which may be introduced from below into the sleeve, in particular such that a cooperation between clamp jaws ( 2 ) and casing ( 9 ) permits transmission of a torque between ween the hollow shaft ( 3 ) and casing ( 9 ) and a second tensioning mechanism is provided in the hollow shaft ( 3 ), by means of which the introduced/introducible casing ( 9 ) may be fixed at the upper rend region thereof in the axial direction, in particular fixing a casing ( 9 ) in the axial direction against gravity relative to the grip head, wherein a flush tube ( 14 ) of supplying a flushing fluid is arranged coaxially in the hollow shaft ( 3 ) and fixed in rotation relative thereto the lower region of which is enclosed by an annular balloon ( 11 ) which may be pumped up with a fluid, in particular a liquid.

1 . A grip head for an earth-drilling system, the grip head comprising
 a tube,   a sleeve provided coaxially on the tube so as to move relative thereto and having a downwardly frustoconically widening lower end,   at least two jaws supported in the tube on the sleeve so as to move radially but not angularly relative to the tube, the jaws having radially outer ends having abutment faces that interact with the widening lower end such that by sliding the lower end over the jaws they are pressed radially inward and form first grab means for an upper end of a casing that is insertable/inserted into the sleeve for transmitting torque between the jaws and the casing and thus between the tube and the casing,   second grab means provided in the tube for securing the casing axially at its upper end so as to hold the casing stationary axially against gravity relative to the grip head,   a circulation pipe for the delivery of a drilling mud extending coaxially in the tube and rotationally fixed thereto,   an annular bladder inflatable by a fluid surrounding the lower end of the pipe, and   means connected to the bladder for inflating it with a fluid and thereby sealing an annular space between the casing and the tube for preventing upward escape of drilling mud from inside the casing through the grip head.   
     
     
         2 . The grip head according to  claim 1 , wherein the second grab means is actuatable by moving the sleeve. 
     
     
         3 . The grip head according to  claim 1 , wherein the sleeve for actuating the first grab means is movable relative to the tube by a first drive and the second grab means is actuatable by a second drive independent of the first drive, both drives being attached to a common support element. 
     
     
         4 . (canceled) 
     
     
         5 . The grip head according to  claim 1  wherein the annular bladder is composed of a flexible elastic material. 
     
     
         6 . The grip head according to  claim 1  wherein the bladder is attached to the circulation pipe. 
     
     
         7 . The grip head according to  claim 1 , wherein the bladder has a fluid supply line supplied with the fluid from a rotary feedthrough fitting attached to the circulation pipe, in particular an inner annular part that is rotationally fixed to the circulation pipe, and is connected to the fluid supply line, and has an inner annular part that is rotationally fixed relative to a surrounding machine assembly, and by which fluid is able to be supplied to the inner annular part. 
     
     
         8 . The grip head according to  claim 7 ,  claim 7 , wherein the rotary feedthrough fitting has three fluid conduits, wherein one fluid conduit is provided for the fluid supply line to the bladder, and two fluid conduits are provided for delivery of fluid to at least one each of two cylinder-piston units for axial movement of the sleeve on the tube in opposite directions. 
     
     
         9 . The grip head according to  claim 1 , wherein the second grab means comprises at least two inner wedges each of which has a radially outwardly directed guide face that interacts with a guide face provided inside the tube with the result that radial inward movement is effected by moving a inner wedge axially downward. 
     
     
         10 . The grip head according to  claim 1 , wherein the inner wedges each have a radially inwardly directed frustoconical contact face formed as a shoulder or step, by which they can each be applied radially with positive engagement to an upper end of a casing. 
     
     
         11 . The grip head according to  claim 10 , wherein the shoulder or step is of right-angled shape formed by a collar that surrounds the upper end of the casing a lower end face of the collar forming the shoulder or step.