Drill string chuck
AssigneeBoart Longyear International Holdings, Inc.
InventorJohn Thomas Stephens
Life of this patent
Estimating the term…
Abstract
A drill rod chuck in which the closing of the jaws is effected through the use of gas springs mounted in the slidable jaw actuating jaw bowl. Further the jaws are supported by bushings against cantilever loading during drilling and the jaws are positively advanced and retracted through slidable interengagement with the jaw bowl.
Claims23
A drill rod chuck for rotating a drill rod string, said chuck having a plurality of jaws moveable inwardly to a closed drill rod gripping position and outwardly to an open drill rod releasing position, an actuator for moving said jaws between said positions, compressed gas operated means exerting force on said actuator to close said jaws and an hydraulic operator for exerting force on said actuator to overcome the force of said compressed gas means to effect opening of said jaws, said compressed gas operated means comprising a plurality of compressed gas springs each comprising a cylinder containing compressed gas and a piston urged by said gas outwardly of said cylinder to the end of its stroke.
In a drill rod chuck as a rotatable spindle having slots in the upper end, jaws mounted in said spindle in said slots with their bottom edges contacting the bottoms of said slots, a jaw actuator bowl slideable on said spindle and supporting said jaws outside said spindle and adapted to move said jaws inwardly of said spindle on downward bowl movement on said spindle, a lower bushing mounted in said spindle to engage and support the bottom edges of said jaws, and an upper bushing fixed to and projecting downwardly into said spindle to engage the upper edges of said jaws as said jaws are moved inwardly to enter said spindle into drill rod gripping position, said bushings supporting said jaws against cantilever forces during drilling.
A drill rod chuck for rotating a drill string, said chuck comprising a spindle to be driven from a power source, a plurality of jaws mounted on said spindle for radial movement into and out of closed drill rod gripping and open drill rod releasing positions, the radial movement into drill rod gripping position being determined by the diameter of the drill rod being gripped, an actuator bowl for moving said jaws between said closed and open positions, said actuator being slideably mounted on said spindle and rotatable therewith, a plurality of gas springs each comprising a cylinder filled with compressed gas and a piston urged outwardly of said cylinder by the compressed gas acting between said actuator bowl and a stop surface fixed to said spindle exerting force on said actuator bowl away from said stop surface to close said jaws, and an hydraulic operator for exerting force on said actuator bowl to overcome the force of said compressed gas springs to open said jaws.
A drill rod chuck for rotating a drill string comprising a spindle adapted to be driven in rotation, said spindle having slots in its upper end, a seal plate slideably mounted on said spindle, stop means to limit downward movement of said seal plate, a jaw bowl slideably mounted on said spindle and fixed to said seal plate, said jaw bowl having jaw receiving undercut slots for registering with said slots in the upper end of said spindle, jaws mounted in said jaw bowl slots to be projected through said spindle slots into the interior of said spindle to grip a drill rod and to be withdrawn from drill rod gripping position upon sliding motion of said jaw bowl, a pressure plate secured to the upper end of said spindle, spring means acting between said jaw bowl and pressure plate to depress said jaw bowl to move said jaws inwardly to drill rod gripping position, a lower bushing mounted in said spindle to support the bottom edges of said jaws when they are moved into said spindle, a cap overlying said pressure plate and having depending legs projecting downwardly through notches in said pressure plate to engage in said spindle slots to overlie said jaws and prevent upward movement thereof, an upper bushing secured to said cap and depending down into said spindle to support the upper edges of said jaws when same are projected into said spindle, a non-rotating hydraulic operator slideable on said chuck below said seal plate, a thrust bearing interposed between said hydraulic operator and said seal plate, said hydraulic operator being adapted on upward movement to force said seal plate and said jaw bowl upwardly against the action of said spring means to effect the withdrawal of said jaws from drill rod gripping position and on downward movement to withdraw said thrust bearing from seal plate engagement to allow said spring means to move said jaw bowl downwardly to close said jaws.
Dependencies are inferred from the claim text.