The DJ type surface bumper jar is a kind of stuck freeing tool for surface down jarring. It is connected with drill stem section, the jarring force is adjusted n surface. Owning some feature such as big jarring force, easy operation, make it especially suitable for stuck freeing of keyboard.Type Parameter DJ46B(4 3/4) DJ70B(7) O.D. (mm) 121(43/4”) 178(7”) Max.jarring force MN (tf) 0.4(41+/-5) 0.8(80+/-5) Sealing pressure Mpa 20(196) 20(196) Stroke(mm) 1500( 59) 1220(48) ID 32(11/4) 51(2”) Threads API NC38(31/2”) NC50(41/2”) Closed length (mm) 3155(124.2”) 3090(121.8”)
