BIT REBOUNDING BUMPER FOR DOWN-THE-HOLE ROCK DRILLING HAMMER

摘要

A bumper (16) located behind the bit (50) shoulder (56), between the bit (50) shoulder (56) and the driver sub (14), is disclosed. The bumper (16), which can be formed of disc spring or rings or other structure made of vibration absorbing materials, isolates the driver sub (14) from a direct, backward impact force of the bit (50). A hammer (10) with the bumper (16), a hammer (10) and bit (50) combination with the bumper (16) and a method of bore hole drilling of an earth formation using a hammer (10) with the bumper (16) are also disclosed.