Control system for rotary drill

In a drilling rig:

• a drill holder rotatable in a desired direction at a desired speed;
• a prime mover;
• a power transmission system connected between said prime mover and said drill holder, said power transmission system comprising:
• a torque converter;
• a modulatable first torque converter clutch in said torque converter;
• a first solenoid operated clutch control valve for operating said torque converter clutch;
• a transmission connected to be driven by said torque converter;
• alternately operable second and third transmission clutches in said transmission;
• first and second solenoid operated clutch control valves for operating said second and third clutches, respectively;
• a selectively operable control system to control the direction and speed of rotation of said drill holder, said control system including means for operating said first valve for modulating said torque converter clutch and for operating a selected one of said second and third valves for engaging said transmission clutches to effect full engagement of said selected one of said transmission clutches prior to full engagement of said torque converter clutch;
• said control system further including a drill control unit comprising a selectively operable directional control member rotatable between neutral, forward, and reverse positions to effect operation of second or third valves, a selectively operable speed control member rotatable to any position between minimum and maximum speed positions to effect operation of said first valve, said drill control unit further comprising interlock means connected between both of said control members to permit movement of said directional control member only when said speed control member is in minimum speed position, and to permit movement of said speed control member only when said directional control member is in forward position.

A mobile drilling rig comprising:

• a rotatable drill holder, a torque converter and transmission connected between a prime mover on the rig and said drill holder, said torque converter including a proportional solenoid operated modulatable torque converter clutch for driving said drill holder at desired rotational speeds, said transmission including a pair of solenoid operated directional clutches selectively operable for driving the drill holder in either forward or reverse directions, and a control system, said control system including a manually operable electromechanical drill control unit having separate control members for direction and speed control, said control unit including interlock means for said control members to permit operator manipulation of the direction and speed control members only in a predetermined sequence to thereby prevent damage to said rig, said control system including means to operate the clutches so as to enable drill holder rotation in either forward or reverse direction from neutral, to enable forward drill holder rotation at any selected speed within a predetermined speed range, to effect reverse drill holder rotation at a predetermined minimum speed, to maintain the selected or predetermined drill speed constant by automatically matching torque to load, and to automatically modulate said clutches so that the selected one of said directional clutch engages before and disengages after said torque converter clutch to thereby smooth out starting and stopping of drill holder rotation.

In a drilling rig:

• a drill holder rotatable in a desired direction at a desired speed;
• a prime mover;
• a power transmission system connected between said prime mover and said drill holder, said power transmission system comprising:
• a torque converter;
• a modulatable first torque converter clutch in said torque converter;
• a first clutch control valve for operating said torque converter clutch;
• a transmission connected to be driven by said torque converter;
• alternately operable second and third transmission clutches in said transmission;
• first and second clutch control valves for operating said second and third clutches, respectively;
• a selectively operable control system to control the direction and speed of rotation of said drill holder, said control system including means for operating said first valve for modulating said torque converter clutch and for operating a selected one of said second and third valves for engaging said transmission clutches to effect full engagement of said selected one of said transmission clutches prior to full engagement of said torque converter clutch;
• said control system further including a drill control unit comprising a selectively operable directional control member rotatable between neutral, forward, and reverse positions to effect operation of second or third valves, a selectively operable speed control member rotatable to any position between minimum and maximum speed positions to effect operation of said first valve, said drill control unit further comprising interlock means connected between both of said control members to permit movement of said directional control member only when said speed control member is in minimum speed position, and to permit movement of said speed control member only when said directional control member is in forward position.