PERCUSSION DEVICE Russian patent published in 1996 - IPC

FIELD: mining industry. SUBSTANCE: percussion device has body 1, piston-striker 2, working tool 3, braking bushing 5 enclosing working tool 3 and locking member 8. Outer surface of braking bushing 5 has annular recess 9 which forms together with body the circular chamber 10 separated by projection 11 of body 1 into pressure chamber 12 and discharge chamber 13 which are communicated with each other through throttling gap 14. Working tool 13 has shoulder 17 and groove 18. Located between shoulder 17 and groove 18 is braking bushing 5. Locking member 8 is installed in groove 18. Chamber 13 is constantly communicated with return line 16. Working tool 3 during its shooting over moves braking bushing 5 by means of locking members 8. Owing to this, working tool 3 is braked by throttling the working fluid through gap 14. When working tool 3 thrusts rock, it returns braking bushing 5 to its initial position. EFFECT: higher operate reliability. 1 dwg