Drill head with locking chuck

A drill head for a core sampling drill adapted to be supported on a drill bed having a drill head feed means, the head having a longitudinal axis and being adapted for movement along the axis by the feed means, the drill head having a chuck concentric with the axis and being adapted to grip an elongated drill rod for rotating the drill rod about the longitudinal axis, the chuck including a collet sleeve and a plurality of chuck jaws, the collet sleeve cooperating with the jaws so that axial movement of the sleeve moves the jaws between jaws extended and jaws retracted positions;

• the drill head including:
• a. an elongated spindle having a central axial bore concentric with the longitudinal axis for accepting the drill rod therein, the spindle being rotated about the longitudinal axis, the chuck cooperating with the spindle so as to rotate therewith, the spindle having first detent location means,
• b. drill head mounting means cooperating with the drill feed means and adapted for longitudinal movement relative to the drill bed, the mounting means being adapted to carry means for rotating the spindle and further including bearings for journalling the spindle for rotation relative to the mounting means,
• c. first and second thrust members being movable axially relative to the spindle, the first thrust member being movable between jaws retracted and jaws extended position and having second detent location means, the second thrust member cooperating with the collet sleeve,
• d. precompressed chuck spring means movable with the first thrust member to apply force to the second thrust member which changes force on the collet sleeve,
• e. detent means movable between jaws extended and jaws retracted positions;
• in the jaws extended position the detent means cooperate simultaneously with the first detent location means in the spindle and the second detent location means in the first thrust member so that the first thrust member attains the jaws extended position and is restricted against axial movement relative to the spindle so that force from the chuck spring means acts on the collet forcing the chuck jaws towards the extended position;
• in the jaws retracted position the detent means are relocated relative to the spindle and the first thrust member so that force applied to the chuck jaws is reduced from that when the detent means are in the jaws closed positions, thus permitting retraction of the jaws,
• f. retaining means cooperating with the detent means to retain the detent means when required in the jaws closed position, thus locating the first thrust member in the jaws extended position,
• the first and second thrust member, the chuck spring means, the detent means and the retaining means being adapted to rotate with the spindle and the chuck;
• the drill head further including:
• g. chuck actuating means supported on the drill head mounting means, the chuck actuating means cooperating with the first thrust member to move the first thrust member relative to the chuck spindle between the jaws retracted and jaws extended positions, so that when the chuck actuating means moves to the jaws extended position the first thrust member is moved relative to the second thrust member to the jaws extended position thus increasing force on the collet sleeve, and simultaneously the detent means is moved to the jaws extended position and is retained therein by the retaining means;
• and when actuating force on the actuating means is released the actuating means and first thrust member are disengaged to permit rotation between the first thrust member and the actuating means with no contact therebetween, the first thrust member remaining in the jaws extended position;
• and when the chuck actuating means are actuated to move from jaws extended position to the jaws retracted position the chuck actuating means engages the retaining means and moves the retaining means so that the detent means are released from the jaws extended position, permitting movement of the first thrust member to release spring forces on the collet thus permitting retraction of the jaws.