ROCK CUTTABILITY DETERMINATION DEVICE Russian patent published in 2014 - IPC E21C39/00 

FIELD: mining.

SUBSTANCE: device has a head with a cutter fixed on a holder, and a driving screw with a nut. The head with cutter are designed with a possibility of their movement along guides fixed on the frame, meanwhile the head is implemented with cylindrical recess. In the head recess from one end a coil compression spring fitted with a sensor, recording the spring compression force is located. The second end of the spring is placed in recess of a thrust washer with a possibility of a thrusting the screw end. The screw is installed in a support fixed on guides, with a possibility of its interaction with the relevant thread of the support bearing at the screw rotating by the automated drive.

EFFECT: ensuring of continuous cutter motion and maintaining of quasi-constant tension in front of the cutter in the top of mainline fracture.

2 dwg