Annular cutter with exchangeable bit ring

Abstract

A core drill is arranged to drill in the ground, the core drill having a sleeve with a first end portion and a bit ring which is detachably attached in a rotationally rigid manner to the first end portion, one of the sleeve and the bit ring having a groove with two converging side faces, and the other one of the sleeve and the groove having a protrusion with two complementary side faces, and the groove and the protrusion being arranged to engage with each other.

1 . An annular cutter arranged to drill in the ground, the annular cutter comprising:
 a sleeve with a first end portion; and   a bit ring,   wherein one of the sleeve and the bit ring has a groove with two converging side faces, and the other one of the sleeve and the bit ring has a protrusion with two complementary side faces, and the groove and the protrusion are arranged to engage with each other to create a friction surface between the bit ring and the sleeve; and   the bit ring is rotationally rigid and detachably attached to the first end portion of the sleeve via a coupling arranged between the first end portion of the sleeve and the bit ring.   
     
     
         2 . The annular cutter according to  claim 1 , wherein the protrusion is arranged on the bit ring. 
     
     
         3 . The annular cutter according to  claim 1 , wherein the coupling is arranged to absorb an axial force which is greater than an axial lifting force necessary for lifting the annular cutter out of the ground, the coupling being placed between the first end portion of the sleeve and the bit ring. 
     
     
         4 . The annular cutter according to  claim 1 , wherein the coupling comprises fastening means taken from a group comprising screws, clamping sleeves and wedges. 
     
     
         5 . The annular cutter according to  claim 1 , wherein the fastening means is arranged in a cut-out in the end face of the sleeve. 
     
     
         6 . The annular cutter according to  claim 3 , wherein the coupling includes a coupling body. 
     
     
         7 . The annular cutter according to  claim 1 , wherein the first end portion of the sleeve and the bit ring comprises complementary toothings arranged to prevent relative rotation between the sleeve and the bit ring. 
     
     
         8 . The annular cutter according to  claim 1 , wherein the bit ring includes several detachable teeth. 
     
     
         9 . An assembly comprising an annular cutter and a drive unit, the annular cutter being connected to the drive unit comprising:
 a sleeve with a first end portion; and   a bit ring,   wherein one of the sleeve and the bit ring has a groove with two converging side faces, and the other one of the sleeve and the bit ring has a protrusion with two complementary side faces, and the groove and the protrusion are arranged to engage with each other to create a friction surface between the bit ring and the sleeve; and   the bit ring is rotationally rigid and detachably attached to the first end portion of the sleeve via a coupling arranged between the first end portion of the sleeve and the bit ring.   
     
     
         10 . The annular cutter according to  claim 2 , wherein the coupling is arranged to absorb an axial force which is greater than an axial lifting force necessary for lifting the annular cutter out of the ground, the coupling being placed between the first end portion of the sleeve and the bit ring. 
     
     
         11 . The annular cutter according to  claim 4 , wherein the coupling includes a coupling body. 
     
     
         12 . The annular cutter according to  claim 5 , wherein the coupling includes a coupling body.