The present invention relates generally to a control system for horizontal directional drills.
The invention is directed to a system. The system comprises a spindle assembly, a motor, a sensor, and a controller. The motor rotates the spindle assembly. The sensor determines a clock position of the spindle assembly. The controller has a virtual brake condition. When in the virtual brake condition, the controller receives signals indicative of the clock position from the sensor. The clock position is compared to a desired orientation. The motor then is actuated to rotate the spindle assembly to the desired orientation.
The present invention is directed to a brake for a spindle assembly on a horizontal directional drill (HDD) system. With reference to
It should be understood that during repetitive drilling operations, a spindle assembly 12 is rotated and advanced by a carriage 5. Advancement stops when the spindle assembly 12 reaches its limit of travel relative to a drill frame 6. At this point, the spindle assembly 12 is disconnected from the drill string. An additional pipe section is then added to the string, extending its overall length. The rotation provided to the spindle assembly 12 by a motor 16 during drilling is in a first rotational direction, while a second rotational direction is used when the spindle assembly 12 is unthreaded from the drill string.
During drilling operations, it may be advantageous to advance the drill string without rotation of the drill bit. For example, in a two-pipe system or downhole mud motor system, advancing a drill string without rotation allows for “steering” of the drill bit. A description of such a two-pipe system with steering is given in U.S. Pat. No. 5,490,569, issued to Brotherton et al. A rotation brake, such as rotation brake 10 (
Further, it may be advantageous to cease the advance or retreat of the drill string for a time. Depending on soil conditions, when no thrust is provided to a carriage, a brake is often required to “lock” the carriage in place, such that the carriage does not drift along the frame of a drilling machine.
The present invention is directed to a system for assuring maintenance of such a position of the spindle assembly 12. Operation of a first embodiment of the system, which uses an actual brake, is shown in
Operation of a second embodiment of the system, which uses a “virtual brake” is shown in
Turning now to
with a rotation assembly 11. The rotation assembly 11 comprises the spindle assembly 12, a gearbox 14 and the motor 16. The motor 16 turns gear and pinion elements 30, 32, 34 within the gearbox 14 which, in turn, rotate the spindle assembly 12. The rotation brake 10 is utilized to stop rotation of the spindle assembly 12.
The spindle assembly 12 comprises a drill string connection 18. The
connection 18, as shown, comprises a shaft 20 and a saver subassembly 22. The shaft 20 is preferably connected by a collar 24 to the saver subassembly 22. The saver subassembly 22 is adapted to thread onto pipe segments 4 (
A rotational sensor 110 may be provided in the spindle assembly 12 to determine its “clock” position, rotational speed, and direction of spin. The rotational sensor 110 may be an accelerometer, a set of magnets, or other mechanism.
A controller 15 (
The controller 15 may operate other elements of the drilling machine 2, such as a wrench assembly 3 for making up segments 4 of the drill string. The controller may also receive information from a downhole tool and tracker system (not shown).
With reference to
When the rotation brake 10 is moved to the engaged position, steps should be taken to protect the motor 16 from damage. For example, the motor 16 may be placed into neutral, slowed or stopped in response to engagement of the rotation brake 10.
Turning back to
Alternatively, the motor 16 may be powered by either a direct current or alternating current electrical power source. An electric motor 16 may comprise a sensor for determining an electrical load on the motor 16. Such a sensor would perform a similar function as pressure sensor 49.
Signals from the pressure sensor 49 may be received by the controller 15 (
With reference to
Continuing with
With reference now to
The rotation brake 10 comprises an actuator assembly 60 and a brake assembly 62. The actuator assembly 60 comprises a cylinder rod 64, a piston 66, a cylinder coupler 68, a hydraulic chamber 69 and a compression spring 70. The compression spring 70 is contained within a spring housing 72 and engaged at a first end 74 to a reaction wall 75 and at a second end 76 to the spring housing. As shown, the spring housing 72 fits within the internal cavity 56 of the motor output pinion 30.
The cylinder rod 64 is coupled to the spring housing 72. Pressurized fluid, such as hydraulic fluid, may be applied to the hydraulic chamber 69 of the actuator assembly 60 through the cylinder coupler 68. The fluid causes the chamber 69 to expand and the piston 66 to move away from the motor output pinion 30. The piston 66 is coupled to the cylinder rod 64. Therefore, as the actuator assembly 60 is activated by fluid, the cylinder rod 64 and spring housing 72 move away from the motor output pinion 30. Additionally, the compression spring 70 is compressed as the distance between the reaction wall 75 and the spring housing 72 decreases.
The brake assembly 62 comprises a brake cover 80, a brake cap 82, and a brake lock 84. The brake cover 80 is attached by connectors 86 to the gearbox 14 (
The brake cap 82 is attached to the brake cover 80 between the brake cover and the gearbox 14 by the connectors 86. The brake cap 82 is shown as a separate element from the brake cover 80, though these may be integrally formed. The brake cap 82 comprises internal features such as splines 90 (
The brake lock 84 comprises external features, such as splines 92 for engaging
the splines 90 of the brake cap. Additionally, the brake lock 84 comprises internal features, such as splines 94 for engaging the lock interface 54 (
While the actuator assembly 60 is shown with a hydraulically actuated piston 66 and a compression spring 70 moving the cylinder rod 64 in response to changes in fluid pressure, other actuator assemblies may be contemplated, such as dual-action hydraulic cylinders, screw drives, etc. Further, while the compression spring 70 of the current invention biases the rotation brake to an engaged position in the absence of fluid pressure, the opposite configuration may be utilized such that hydraulic pressure is required for activation of the rotation brake.
While the features shown for interaction between the rotation brake 10 and motor output pinion 30 are splines 90, 92, 94, other features may be utilized, such as geometric profiles (for example, hexagonal cavities), rotational stops, etc. Additionally, the interface between the brake lock 84 and brake cap 82, and/or the interface between the brake lock 84 and lock interface 54, may allow for some spring resistance when in the second position to quickly slow then stop rotation of the motor output pinion 30 rather than providing an instantaneous stop.
Rotation of the motor output pinion 30 and actuation of the rotation brake 10 may cause pressure to build up in the gearbox 14. An internal passage 100 exists due to a central bore through the motor output pinion 30, spring housing 72 and cylinder rod 64. The internal passage should allow transmission of pressure changes between the gearbox 14 and a barrel end 102 of the rotation brake 10. An air vent 104 may be provided at the barrel end 102 of the rotation brake 10 such that sudden increase and decrease of pressure within the gearbox 14 is translated to the atmosphere, preventing pressure-related resistance to actuation of the rotation brake 10. O-Rings 105 are placed about a periphery of the piston 66 to isolate the air existing in the barrel end 102 from the hydraulic chamber 69 of the barrel end. A mechanical switch 108, pressure sensor, or the like may be provided at the coupler 68 or elsewhere to indicate the hydraulic pressure in the chamber 69. This information may be provided to a control system (not shown) to indicate whether the brake 10 is actuated such that the motor 16 (
With reference now to
With reference now to
With reference to
If a change is made and the rotation brake 10 is activated from a rotating condition such as at step 204, rotation is slowed at step 206 through the slowing of the motor 16 output. Preferably, rotation of the spindle assembly 12 is slowed to less than five RPM. The rotation brake 10 is then activated at step 208.
If the brake is actuated, the proper engagement of the brake is checked at step 209. The logic associated with this step is shown in more detail in
For example, the motor 16 transmits a clockwise torque to the spindle assembly 12 at step 210. The pressure sensor 49 may indicate a pressure spike at step 210. Such a spike means that the brake 10 has mated with the motor output pinion 30 (
The motor 16 then transmits a counterclockwise torque to the spindle assembly 12 at step 216. Like in step 210, the pressure sensor 49 may indicate a pressure spike at step 216. This spike indicates the brake 10 has mated with the motor output pinion 30 (
When the splines of the pinion 30 (
When an error is generated at step 212, the spindle assembly 12 is automatically rotated back and forth over a small angular displacement as shown at step 220. The small angular displacement can be as large as 20 degrees or as little as 1 degree or less. The goal of alternating the rotation is to cause the rotation brake 10 to properly mate with the motor output pinion 30 (
Once the brake is confirmed to be on at step 218, the brake remains on until a
change is detected, causing the brake to disengage at step 222 and return to idle.
While the rotation brake 10 is activated, the carriage 5 may advance a drill pipe segment 4 without rotation to “steer” the drill string as discussed above. Because any rotation of the spindle assembly 12 and drill string during steering will tend to cause error in the bore path, assurance of accurate spindle assembly position is advantageous.
It should be appreciated that a downhole sonde (not shown) supported by the drill string may include a clock position sensor. This sensor (not shown) may be utilized with the rotational sensor 110 on the spindle assembly 12 to allow the controller 15 to correct for any error caused by windup of the drill string by releasing the brake 10 and reorienting the spindle.
As discussed above, the motor 16 may be used to act as a virtual brake system 300. With reference to
The virtual brake system 300 (
So long as the spindle assembly 12 remains within an accepted tolerance from the desired clock position, normal operations of the drilling system may be maintained with the virtual brake system 300 engaged. Error tolerance may be as much as fifteen degrees. Preferably, the tolerance is 3 degrees or less. Tolerances of 0.5 degrees or less may be used. The smaller the error tolerance, the more precise the steering. However, extremely small tolerances may generate more corrections than desired.
While the virtual brake system 300 is actuated, the drilling system may advance a pipe segment 4 using the carriage 5 without rotation. The geometry of the downhole tool (not shown) will cause it to steer the advancing drill string.
While advancing the pipe segment 4, underground conditions may cause the pipe segment 4 and spindle assembly 12 to deviate from the desired orientation. The rotational sensor 110 systematically sends signals to the controller 15 indicating the clock position of the spindle assembly 12. The controller 15 compares the clock position to the desired orientation.
When the clock position of the spindle assembly 12 exceeds the error tolerance, the controller 15 indicates a clock position error at step 308. The controller 15 will transmit a correction signal to the pump 48 (
An activation status of the brake is monitored by the controller 15 at step 312. If activation is maintained at step 312, the spindle assembly 12 position continues to be monitored. If the virtual brake is deactivated at step 312, the spindle assembly 12 returns to standard operation at step 314. During standard operation, the spindle assembly 12 may float during thrust, or may be rotated by the motor 16 if desired.
It should be appreciated that a downhole sonde (not shown) supported by the drill string may include a clock position sensor. This sensor (not shown) may be utilized with the rotational sensor 110 on the spindle assembly 12 to allow the controller 15 to correct for any error caused by windup of the drill string. Deviation or rotation of the downhole tool during thrust without rotation may be caused by drill string wind up. Such deviation may necessitate corrections by the virtual brake system 300 even when the rotational sensor 110 does not sense significant movement.
Additionally, one of ordinary skill in the art will appreciate that use of a virtual brake system 300 may be utilized on drills where the actual rotation brake 10 is eliminated.
Similarly, a virtual brake system 400 may be utilized to monitor a position of the spindle assembly 12 when no thrust is desired. For example, the virtual brake system 400 may be engaged to maintain a position of the spindle assembly 12 along the drill frame 6.
The drill frame 6 may have a system, such as a rack 17 (
Typically, when translation of the carriage 5 is not desired, a friction brake is used to maintain the position of the carriage. However, it may be advantageous to avoid repetitive application of the brake, which causes wear to portions of the drill 2. In addition, physical brakes may, due to operator error, cause damage to the drill when, for example, an operator applies the friction brake while thrust is being applied. Finally, safety margins are applied to avoid damage due to operator error, such as time delays automatically applied when the brake is actuated, decrease the responsiveness of the machine and prevent efficient autonomous operation.
An exemplary operational method for the virtual brake 400 is shown at
If an operator is present at the control station at 406, the controller 15 determines if the thrust control joystick is in neutral at 410. The virtual brake will not be active if the thrust control joystick is actuated to move the carriage 5 toward or away from the borehole. If the joystick is in neutral at 410, the position sensor 112 provides a carriage 5 position capture at 412.
The position sensor 112 is monitored at 414 to determine whether or not the carriage has moved from the captured position. The tolerance of the sensor may be set by an operator, or may be determined by the controller 15 software. For example, a tolerance of five millimeters may be allowed before the sensor 112 determines that the carriage 5 has moved. Larger and smaller tolerances may be contemplated, however, carriage 5 drift is disfavored. If the carriage 5 has not moved from the captured position at 414, the controller 15 continues to monitor signals from the position sensor 112 so long as the thrust control joystick remains in neutral at 416. If the joystick is no longer in neutral at 416, the system returns to standard operation at 404.
If the carriage 5 has moved from the captured position at 414, the controller applies a correction signal to a pump, causing the carriage motor to move the carriage 5 along the rack 17 toward the captured position at 418. The detected deviation from the captured position may be either toward or away from the borehole, and the correction will move the carriage 5 in the opposite direction from the deviation.
The virtual carriage brake 400 may be toggled on as an option for operation of the drill 2, or may always be active while the operator is in the seat and the joystick is in neutral.
The virtual carriage brake system 400 allows for quicker control response of the carriage 5. In a system with a standard friction brake, a built-in time delay is required to allow the friction brake release system to pressure up, so that the brake will be released prior to the movement of the carriage 5. Such a time delay prevents wear on a partially released friction brake. With the virtual thrust brake disclosed herein, immediate response of the thrust movement can be obtained when the operator commands movement.
In operation, with the rotation brake 10 disengaged, the spindle assembly 12 is rotated by the motor 16 to connect to a pipe segment 4. The spindle assembly 12 is then advanced along the drill frame 6 by the carriage 5 while rotating to connect the pipe segment 4 to a drill string. The spindle assembly 12 continues rotation and advancement to advance the drill string into the ground. As shown in
The rotation brake 10 is then disengaged, and the rotation of the spindle assembly 12 reversed to disconnect the spindle assembly from pipe segment 4. As shown in
One of ordinary skill in the art will appreciate that the above steps may be performed substantially in reverse to remove a pipe segment from a pipe string during backreaming operations of the horizontal directional drill 2.
It should be appreciated by those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention. It is intended that the present invention cover such modifications and variations as come within the scope and spirit of the appended claims and their equivalents.
Number | Date | Country | |
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63510563 | Jun 2023 | US | |
62429550 | Dec 2016 | US |
Number | Date | Country | |
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Parent | 17473419 | Sep 2021 | US |
Child | 18341309 | US | |
Parent | 16934757 | Jul 2020 | US |
Child | 17473419 | US | |
Parent | 15830949 | Dec 2017 | US |
Child | 16934757 | US |
Number | Date | Country | |
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Parent | 18341309 | Jun 2023 | US |
Child | 18754382 | US |