Improvements in Chucks or Drill Caps for Percussive Rock Drills, Hammer Picks, and like Percussive Machines.

摘要

119,059. Ellacott, R. E. Aug. 14, 1917. Loose tools and bits, retaining. - A chuck or drill cap for rock drills, hammer picks, and like percussive machines, comprises a hollow conical nose portion a' fitted with sliding jaws c, c1 having T- headed or other lugs c2, c3 engaging corresponding slots a2, a3 in the wall of the cap. The jaws form an elliptical opening greater than the body of the drill steel b but smaller than the collar b1 of the steel. A spring or springs may be provided either to press the jaws to the bottom of the slots or below the jaws' to press them out of action or to take up waste blows. Springs may also be placed between the jaws to separate them. The cap a may be integral with the machine or secured thereto by a threaded or other joint.