Title:
【発明の名称】衝撃式試錐装置及び試錐チューブ
Document Type and Number:
Japanese Patent JP2002543311
Kind Code:
A
Abstract:
A percussive drill for extension drilling includes a drill bit, a tube having a male screw thread attached to a female screw thread of the drill bit, and a rod having a male screw thread attached to a female screw thread of the tube. Central passages of the rod and tube are aligned with one another to conduct flushing fluid to the drill bit. The drill bit drills a hole whose diameter is from 60-170 mm and at least twice the outer diameter of the rod. A total area of a cross-sectional surface of the tube is within 100-125% of a total area of a cross sectional surface of the rod.
Inventors:
Larson, Kenneth
Mollen, Rolf
Mollen, Rolf
Application Number:
JP2000613916A
Publication Date:
December 17, 2002
Filing Date:
April 25, 2000
Export Citation:
Assignee:
Sandvik Actie Borrag (Puble)
International Classes:
E21B17/042; (IPC1-7): E21B17/042
Attorney, Agent or Firm:
Takashi Ishida (3 others)