Percussive air hammer and core bit apparatus

An airhammer for use in applying successive percussive blows to a percussive drill bit for taking core sample material from the bottom end of a bore hole while drilling the bore hole, said airhammer including a housing, an airhammer piston reciprocable in said housing, valve means for alternately directing air to opposite ends of said airhammer piston and exhausting air therefrom, a core tube extending longitudinally and centrally through said housing and said airhammer piston, and means for conducting a portion of the air supplied to said airhammer to said core tube to convey core material therethrough;

• said valve means including a valve tube surrounding said core tube and forming a first annular passage therebetween, said means for conducting a portion of the air to said core tube including an air tube concentric with said core tube to define a second annular passage therebetween communicating with said first annular passage, said air tube being secured to said valve tube, said valve means including coacting valve portions on said valve tube and piston and on said piston and housing, said valve tube having an inlet leading from said first annular passage to said valve portions, said valve means further including a third annular passage between said air tube and piston through which exhausting air can flow.

An airhammer for use in applying successive percussive blows to a percussive drill bit for taking core sample material from the bottom end of a bore hole while drilling the bore hole, said airhammer including a housing, an airhammer piston reciprocable in said housing, valve means for alternately directing air to opposite ends of said airhammer piston and exhausting air therefrom, a core tube extending longitudinally and centrally through said housing and said airhammer piston, and means for conducting a portion of the air supplied to said airhammer to said core tube to convey core material therethrough;

• in combination with a core bit carried by said airhammer housing and having an anvil engageable by said airhammer piston, said bit having a central core opening communicating with said core tube, and core cutting means disposed about said core opening, said means for conducting a portion of the air to said core tube including an air tube concentric with said core tube to define an annular air passage therebetween, said core tube having ports spaced circumferentially thereof and leading at an angle from said air passage into said core tube in the direction of movement of the core material, said core tube and air tube extending into said core bit and terminating adjacent said central core opening.

An airhammer for use in applying successive percussive blows to a percussive drill bit for taking core sample material from the bottom end of a bore hole while drilling the bore hole, said airhammer including a housing, an airhammer piston reciprocable in said housing, valve means for alternately directing air to opposite ends of said airhammer piston and exhausting air therefrom, a core tube extending longitudinally and centrally through said housing and said airhammer piston, and means for conducting a portion of the air supplied to said airhammer to said core tube to convey core material therethrough;

• in combination with a core bit carried by said airhammer housing and having an anvil engageable by said airhammer piston, said bit having a central core opening communicating with said core tube, and core cutting means disposed about said core opening, said valve means including a valve tube surrounding said core tube and forming a first annular passage therebetween, said means for conducting a portion of the air to said core tube including an air tube concentric with said core tube to define a second annular passage therebetween communicating with said first annular passage, said air tube being secured to said valve tube, said core tube and air tube extending into said core bit and terminating adjacent said central core opening.