초록 ▼

A vertical drill rig is provided with a hydraulic crowd mechanism for crowding down a drive kelly having a rotating drilling tool supported from the lower end thereof. The crowd mechanism includes a drum having first and second cables wound in opposite senses thereon. The drum is rotated by a hydrau

A vertical drill rig is provided with a hydraulic crowd mechanism for crowding down a drive kelly having a rotating drilling tool supported from the lower end thereof. The crowd mechanism includes a drum having first and second cables wound in opposite senses thereon. The drum is rotated by a hydraulic motor driven by pressure regulated fluid supplied by an accumulator charged with fluid received from a hydraulic pump. The cables couple the drive kelly to the rig such that, when the hydraulic motor rotates the drum in a given direction, the first cable is paid out to lower the drive kelly while the second cable is simultaneously taken up to crowd down the drive kelly relative to the rig. Such a construction and arrangement provides a substantially constant crowd down force on the rotating drilling tool irrespective of its vertical rate of penetration into the earth.

대표청구항 ▼

In a vertical drilling rig, a kelly crowd mechanism comprising in combination: a drive kelly; a crowd drum having a cable thereon which is drivingly coupled to crowd down said drive kelly when taken up on said drum; a hydraulic motor; a normally disengaged clutch operable to couple said motor to sai

In a vertical drilling rig, a kelly crowd mechanism comprising in combination: a drive kelly; a crowd drum having a cable thereon which is drivingly coupled to crowd down said drive kelly when taken up on said drum; a hydraulic motor; a normally disengaged clutch operable to couple said motor to said drum in response to pressurized fluid; a pressure regulated source of fluid; a motor control valve manually operable to gate pressurized fluid supplied by said source to rotate said hydraulic motor and simultaneously engage said clutch to thereby rotate said crowd drum and thereby crowd down said drive kelly; and a clutch control valve manually operable to gate pressurized fluid supplied by said source to engage said clutch and apply a brake to said crowd drum when said motor control valve is closed.