Patent Application
20230304358
The present disclosure relates to underground drilling machines such as horizontal directional drilling (HDD) machines. Aspects of the disclosure relate particularly to the ability for an exit side HDD machine to have a selectable freewheel mode within the rotational drive unit thereof, for example when used as an exit side rig in a dual rig operation.
The present disclosure provides, in one aspect, a horizontal directional drilling machine including a drill string rotational drive unit having an output member configured to connect with and selectively drive rotation of a drill string. The rotational drive unit includes a hydraulic motor. A hydraulic circuit has a configuration that puts the motor in a drive mode to apply torque and a second configuration that puts the motor in a freewheel mode disabled from applying torque. The hydraulic circuit includes a first fluid flow path for connecting the hydraulic motor through a first rotary ball valve to one of an inlet side and an outlet side of a drive pump, and a second fluid flow path for selectively connecting the hydraulic motor through a second rotary ball valve to the other one of the inlet side and the outlet side of the drive pump. When the hydraulic circuit is in the first configuration and fluid flows between the drive pump and the hydraulic motor along the first and second fluid flow paths, there is no pressure drop across the first and second rotary ball valves.
The present disclosure provides, in another aspect, a horizontal directional drilling machine including a cam-lobe radial piston hydraulic motor having an output member configured to connect with and selectively drive rotation of a drill string. A hydraulic circuit has a first configuration that puts the hydraulic motor in a drive mode to apply torque to the drill string through the output member. The hydraulic circuit has a second configuration that puts the hydraulic motor in a freewheel mode disabled from applying torque to the drill string. The hydraulic circuit includes a first fluid flow path for selectively connecting the hydraulic motor to one of an inlet side and an outlet side of a drive pump, and a second fluid flow path for selectively connecting the hydraulic motor to the other of the inlet side and the outlet side of the drive pump. When the hydraulic circuit is in the freewheel mode, the first and second fluid flow paths are blocked. When the hydraulic circuit is in the drive mode, there is no reduction in cross-sectional area along the first fluid flow path and there is no reduction in cross-sectional area along the second fluid flow path.
The present disclosure provides, in yet another aspect, a horizontal directional drilling machine including a cam-lobe radial piston hydraulic motor having an output member configured to connect with and selectively drive rotation of a drill string. The hydraulic motor is operable in a drive mode to enable torque application to the drill string through the output member, and the hydraulic motor is operable in a freewheel mode disabled from applying torque to the drill string. A hydraulic circuit includes rotary ball valves operable to control the flow of fluid to and from the hydraulic motor for switching the hydraulic motor between the drive and freewheel modes.
The present disclosure provides, in yet another aspect, a horizontal directional drilling machine including a rotational drive unit having an output member configured to connect with and selectively drive rotation of a drill string when the rotational drive unit is in a first mode. The output member of the rotational drive unit is configured to be rotated by the drill string when the rotational drive unit is in a second mode. An operator input device allows an operator to select between the first and second modes of the rotational drive unit. A display is configured to display information regarding the status of the rotational drive unit to the operator, including displaying whether the rotational drive unit is in the first mode or the second mode. A control system includes a controller connected for signal communication with the rotational drive unit, the operator input device, and the display. The control system is configured to, in response to receiving an input to the operator input device to change between the first and second modes: transition the rotational drive unit between the first and second modes, and change the response of one or both of the operator input device and the display to provide an indication to the operator that the rotational drive unit is in transition between the first and second modes.
Other features and aspects of the disclosure will become apparent by consideration of the following detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
It is not uncommon for the rotation of the tail string 112 to be inconsistent during the reaming operation. As the reamer 108 engages the ground formation, it very often encounters variation of properties within the ground formation, and this can result in variations in the torque required to rotate the reamer 108. This characteristic combined with the torque wind-up of the drill string 104 results in variations of revolutions per minute (rpm) of the reamer 104 and the tail string 112. At times this variation can become significant. Thus, in a set-up where the tail string 112 is coupled directly to the reamer 108, as illustrated in
In order to allow the tail string 112 to rotate freely in the embodiment described herein, to follow the rotation of the reamer 108, the rotational drive unit 116 of the exit side HDD machine 100B can be enabled with a freewheel mode. As explained in further detail below, the freewheel mode is a mode that occurs within the rotational drive unit 116, which allows free rotation of the tail string 112 (i.e., without opposing torque/drag) while it remains connected to the rotational drive unit 116—rather than a disconnection of the tail string 112 from the rotational drive unit 116. Through this connection the exit side HDD machine 100B is able to push or pull the reamer 108 in coordination with the entry side HDD machine 100A that is pulling and rotating the reamer 108.
As illustrated in
In addition to the rotational drive unit 116,
The other mode of the motor 130 is a freewheel mode (
In the illustrated construction, each motor 130 is connected to a flushing line 142, a drain line 144, and a pair of input/output lines 146, 148. The lines 146, 148 may be referred to as system lines or drive lines of the hydraulic circuit 138, and these lines 146, 148 provide fluid flow paths extending between the drive pump 164 and the motors 130. When the hydraulic circuit 138 is placed in a first configuration, as illustrated in
The flushing line 142 extends from a flushing pump 152 in fluid communication with a supply of hydraulic fluid, referred to as tank or reservoir 156. The flushing fluid can be provided in a number of ways, this example with a dedicated flushing pump is intended to illustrate the principle. The drain line 144 also extends to the tank 156, which is unpressurized. Thus, hydraulic fluid pumped through the flushing line 142 by the flushing pump 152 passes through the motors 130 and then exits via the drain line 144 to return to tank 156. A spring-actuated check valve 160 is positioned along the drain line 144 and sets a minimum pressure in the lines 142, 144 as the flushing pump 152 operates to drive fluid through the motors 130.
Along the inlet/outlet lines 146, 148, respective rotary ball valves 168, 170 are provided. According to the following disclosure, the rotary ball valves 168 can be actuated separately or in tandem by a single actuator 172 to selectively open and close the inlet/outlet lines 146, 148 between the motors 130 and the drive pump 164. Furthermore, the rotary ball valves 168, 170 are used, to control the flow of hydraulic fluid between the pump 164 and the motor(s) 130, in contrast with a directional control spool valve as would normally be provided for control of the motors 130. A portion of the drive pump 164, or a separate pump, labeled here as 176 can be provided to charge one or more optional hydraulic pressure accumulators 180. The accumulators 180 are connected to the inlet/outlet lines 146, 148 running between the drive pump 164 and the motors 130. The accumulators 180 can be connected to the inlet/outlet lines 146, 148 through respective check valves that only allow fluid flow from the accumulator 180 and not into the accumulator 180. The accumulators 180 are filled with fluid supplied from the pump 176, through an accumulator cut-off valve 184. The accumulator cut-off valve 184 is open only when the inlet/outlet lines 146, 148 are active for driving the motors 130, and the accumulator cut-off valve 184 is closed when the motors 130 are put into the non-driving freewheel mode. In the drive mode, the accumulators 180 provide charge pressure to the motor 130, which is in excess of the back pressure generated by the spring-actuated check valve 160. In the freewheel mode, the accumulators 180 are blocked from fluid supply and allowed to drain to tank 156.
The optional accumulators 180 as well as the inlet/outlet lines 146, 148 are selectively connected to tank 156 through respective switching valves 188, 190 (e.g., “dump valves” or “drain valves”) and a drain line 192. If provided, the accumulators 180 operate to reduce the potential for cavitation while the motor 130 is driven by the drive pump 164. The accumulators 180 also dampen fluctuations in the charge pressure that are the result of the charge pressure being used for other purposes, not shown in this schematic. However, they must be drained to enable the case pressure in the motor 130 to retract the pistons for freewheeling. When the valves 188, 190 are opened to drain the accumulators 180 for switching over to freewheel mode, the pressure in the lines 142, 144 is maintained by the spring force of the spring-actuated check valve 160, to be higher than the back pressure generated as the accumulators 180 drain. In other constructions, the control system 138 is provided without the accumulators 180 and without the accumulator cut-off valve 184.
Switching modes of the motors 130 in the illustrated construction is accomplished via the hydraulic control system 138, under the direction of the rotary drive control system 400, e.g., the electronic controller 200 (e.g., microprocessor) thereof. The controller 200 can generate one or more signal outputs via an I/O section 202 in response to a trigger or command, which can come from an operator control (e.g., on the machine or off the machine and wireless connected) operated by a human operator and/or a fully- or semi-automated program executed by the controller 200. In addition to switching of the rotary ball valves 168, 170 (via the actuator 172 which is controlled by valve 212), mode switching includes the switching of the drain valves 188, 190 as well as the accumulator cut-off valve 184, if the accumulators 180 are provided. As illustrated, the controller 200 can provide an electronic signal directly to a solenoid of the accumulator cut-off valve 184. Although independent signals can also be provided to valve 212 to control the actuator 172 and/or to valve 214 to control the drain valves 188, 190 in some constructions such that they are direct-acting valves. The illustrated construction provides for pilot pressure operation, e.g., via a shared pilot pressure line 206 connected to a pilot pressure generated by a pilot charge pump 208 in fluid communication with hydraulic fluid in the tank 156. Pilot pressure can be supplied to a first control valve 212 (“system line shutoff actuation valve”) that controls operation (cylinder position) of the actuator 172 and a second control valve 214 (“freewheel enable pilot control valve”) that controls operation (switching open) of the drain valves 188, 190, each of which is provided as a two-position, normally-closed, pilot-actuated switching valve. In the case of the first control valve 212, the two positions are configured to control the reversal of which side of the actuator 172 (e.g., double-acting cylinder) is coupled to the pilot pressure line 206 and which side is coupled to tank 156. The second control valve 214 is configured to control whether the drain valves are coupled to tank 156 or coupled to the pilot pressure line 206. Although valves for larger flow capacity have larger spools and require higher forces to operate (such that larger valves tend to be pilot operated), it is contemplated for the disclosed valves to be either direct-acting or pilot-operated, regardless of what is described and shown explicitly.
As illustrated in
Several detailed features of parts of the hydraulic control system 138 are described with reference to
In an alternate construction, the drain valves 188, 190 can be actuated to open without provision of the second control valve 214 (e.g., only the first control valve 212 is provided). For example, the pilot pressure for actuating the drain valves 188, 190 can be provided from the line that supplies pressure from the first control valve 212 to actuate the actuator 172 in
In operation, the first HDD machine 100A is operated to build up the drill string 104 and drill underground toward the second HDD machine 100B. Once the head of the drill string 104 protrudes from the ground at the second HDD machine 100B, the back reamer 108 is attached to the drill string 104, and the tail string 112 is built up one rod at a time from the second HDD machine 100B. Similar to the drill string 104, the tail string 112 can include sequential rods joined with respective threaded joints. Making up joints between rods of the tail string 112 includes use of the rotational drive unit 116 to apply torque to the rod being added to the tail string 112. During this process, the tail string 112 is held fixed by a vise on the second HDD machine 100B, and the rotational drive unit 116 can also slide as necessary along the rack 120 to allow the rods to join axially during threading. Because torque to the tail string 112 is required during joint making, the motors 130 are in the first or drive mode (
While the descriptions of freewheeling herein can refer to (hydraulically or otherwise) setting the rotational drive unit 116 to a configuration disabled from generating torque, it is also noted that freewheeling is but one optional method of setting the rotational drive unit 116 to act as a slave or follower, wherein the output of the rotational drive unit 116 is rotated passively from the drill string (e.g., tail string 112). For example, the rotational drive unit 116 may remain in a regular or modified torque-transmitting configuration, despite the rotational drive unit contributing substantially nothing to the drill string rotation, and in some cases actively opposing the drill string rotation. Except where it would be explicitly contradictory, descriptions of freewheeling throughout the present disclosure should be understood to also apply more generally to slave or follower operation of a rotational drive unit 116.
The rotary drive control system 400 includes a display device 300 for communicating the status of the HDD machine 100B to an operator, an operator input device 310 for allowing an operator to select modes of operation, and control algorithms for operating the machine, including the rotational drive unit 116, in coordination with other machine controllers 350 of the HDD machine 100B, to automate and coordinate various operations.
The operator input device 310, shown schematically in
If the control button 312 is depressed for a predetermined period of time, while the HDD rig 100B is in normal operation mode, the controller 200 will recognize that the operator wishes to switch to the freewheel mode. The controller 200 will evaluate the other rig controller functions to ensure:
Once the controller 200 confirms these conditions it will initiate the process to switch to the freewheel mode, e.g., including control of the rotary ball valves 168 and 170, the control valves 212, 214, and the accumulator cutoff valve 184, as is described above. With the hydraulic system described herein, this process may take two seconds or more, such as three to four seconds, and the time required for this process may be affected by the temperature of the hydraulic oil. Rotation of the output member 136 of the rotary drive 116 during this transition period can potentially damage the motor(s) 130, thus the operator of the second HDD machine 100B should be provided a clear indication of the status of the mode change, so that the operator can communicate effectively and efficiently with the operator of the first HDD machine 100A. The indication of the status of the mode change is provided by the rotary drive control system's transition mode, which can include one or more means of transitional display, e.g., illustrated as
The rotary drive control system 400 will monitor the HDD machine 100B, including, in the illustrated hydraulic embodiment, the charge pressure with sensor 182 and the case pressure with sensor 162 and the position of the rotary ball valves 168, 170 with proximity switches (that are not shown). Once the control system 400 confirms that the charge pressure has dropped to a predetermined low pressure, and that the case pressure is more than the charge pressure, and that the rotary ball valves 168, 170 are in the second position, it will determine that the system is in the freewheel mode. At that point, the light 314 of the control button 312 will stop flashing, and it will be illuminated continuously. The status indicator 302 will also stop flashing, the symbol “N”, as illustrated in
Other types of hydraulic systems that could be utilized to provide a freewheel mode will also require a transition period between modes. Thus, the control system described herein has utility for the hydraulic system described herein, but it also has utility with other hydraulic systems. In addition, if the rotary drive unit 116 is powered by an electric motor rather than a hydraulic motor, the system may still operate with a normal driving mode and separate freewheel or follower mode, and may also incur a transition period for mode changing. Thus, the control system 400 described herein has utility with an electric drive system. An electric rotary drive unit can be set to follower mode by ceasing energization or a small, controlled energization that is largely or completely imperceptible to the HDD machine 100A driving the drill string 104 and the tail string 112. Whether de-energized or only slightly energized, the follower mode of the electric rotary drive unit allows the rotary drive unit output to be passively rotated from the rotation of the tail string 112, similar to a hydraulic motor configured in a torque-disabled freewheel setting. The fact that this disclosure describes in greatest detail the context of one type of hydraulic drive system, is not necessarily limiting.
In addition to controlling the hydraulic system 138, the controller 200 can be configured to affect other systems of the exit side HDD machine when in the freewheel mode. In some embodiments, the controller 200 can affect the operation of the carriage drive system 500. In one embodiment, the controller 200 affects the operation of the carriage drive system 500 when in the freewheel mode, to only apply a pulling force onto the reamer. In another embodiment, the controller can affect the automatic control of the carriage drive system so that the function of that system is optimized for the freewheel mode.
If the button 312 is depressed for a predetermined period of time, while the HDD rig 100B is in freewheel mode, the controller 200 will recognize that the operator wishes to switch to the normal mode. The controller 200 will evaluate the other rig controller functions to ensure:
Once the controller 200 confirms these conditions it will initiate the process to switch to the normal mode, e.g., by control of the rotary ball valves 168 and 170, control valves 212 and 214, and accumulator cutoff valve 184. This process may include staggered activation of these various devices. For instance, it has been discovered that with the hydraulic system described herein, if the rotary ball valves 168, 170 are opened before the accumulator cutoff valve 184 is opened, a pressure spike will be generated by the in-rush of hydraulic fluid. Thus, in one embodiment the accumulator cutoff valve 184 is opened first, while the ball valves 168, 170 are opened slightly later. Thus, this process may take two seconds or more, for example seven seconds. With cold oil temperature, this process may take even longer than seven seconds to complete, for example up to 30 seconds. Rotation of the output member 136 of the rotary drive unit 116 during this transition period will potentially damage the motor(s) 130, thus the operator of the second HDD machine 100B should be given a clear indication of the status of the mode change, so that the operator can communicate effectively and efficiently with the operator of the first HDD machine 100A. The indication of the status of the mode change is provided by the display 300 and the display device (light 314) integrated with the control button 312. When the control unit 200 recognizes that the operator wishes to switch from freewheel to the normal drive mode, after the control button 312 is pressed for two seconds, the light 314 of the control button 312 will flash during a transition period. During this time, the indicator 302 will change to display a flashing symbol “N”, representing neutral, as an indication that the rotational drive unit 116 is transitioning from the freewheel mode. The indicator 302 may also be illuminated as yellow during this transition period.
The control system 400 will monitor the charge pressure with sensor 182. Once the system confirms that the charge pressure has reached a predetermined pressure and it that the ball valves 168, 170 are in the first position, it will determine that the system is safely in the normal mode. At that point the light 314 of the control button 312 will stop flashing, and it will be turned off. The indicator 302 will also stop flashing the symbol “N”, and a different symbol will be on continuously, a symbol indicating the status of the rotary drive, such as “L” for low speed, “M” for medium speed, or “H” for high speed. Other symbols can be used to indicate that status of the rotary drive unit 116, such as numbers like 1, 2, 3, or 4. The indicator 302 could be illuminated as green at this point. The operator of this machine, the second HDD machine 100B, will be in communication with the operator of the first HDD machine 100A during this process, to communicate information about this mode change.
In addition to the processes defined for manual selection of a mode, by the operator, the control system 400 includes logic for a suspend mode or “freewheel suspend,” which is a mode that the controller 200 automatically switches into and out of. The suspend mode can be accessed exclusively when set or commanded into the freewheel mode by the operator and can switch automatically back and forth to/from the freewheel mode. While in the freewheel mode, the freewheel suspend mode is automatically initiated, or entered into, whenever an operator uses a machine control to clamp the drill rod (tail string 112) with a vise 520 and is automatically exited when an operator uses a machine control to release the vise 520. As shown in
The operator of the second HDD machine 100B will use the vise control when a drill rod in the tail string 112 has been pulled into the bore hole far enough that a joint between the drill rod and the rotary drive unit 116 is positioned at the vise 520. When that occurs, the operator at the second HDD machine 100B will communicate with an operator at the first HDD machine 100A, to request that the first machine interrupt the pull-back process. The operator of the first HDD machine 100A will stop its thrust and rotary drive systems which are powering the drill string 104 and the reamer 108. Once the drill string 104, the reamer 108, and the tail string 112 stop, the operator of the second HDD machine 100B will clamp the tail string 112 with its vise 520, as a first step in the process to add a drill rod to the tail string 112. This requires the rotary drive unit 116 to be unthreaded at that joint. Once unthreaded, the operator will retract the rotary drive unit 116 back, making room for a new drill rod to be added to the tail string 112, the processes associated with unthreading the rotary drive unit 116, moving it back along the rack of the second HDD machine 100B, and then attaching a new drill rod involve normal use of the rotary drive and thrust systems. In order to minimize required operator input, and to speed-up the overall process, the control system 400 will automatically switch from the freewheel mode to the freewheel suspend mode, which is a momentary limited drive mode, in response to the vise 520 being clamped while the machine is in the freewheel mode. This automatic switch in the modes further includes a transition phase, where the machine is transitioning from freewheel to the freewheel suspend mode, which provides the drive capability for the rotary drive unit 116 to complete the drill rod addition. The change in the display is illustrated by comparison of
The control system 400 may automatically disable some operator controls during the transition phase, to ensure that an operator does not make a mistake and operate the machine systems during the transition. The display will clearly inform the operator of the second HDD machine 100B that it is in a transition phase, so that information could be communicated to the operator of the first HDD machine 100A, to reduce the potential that the operator of the first HDD machine 100A would do anything to cause the tail string 112 to rotate.
This automated process will eliminate the need for an operator to separately activate the freewheel mode control 312 and fully exit freewheel mode when the vise 520 is clamped, which would otherwise be necessary, in order to switch to normal mode, so that the machine systems could be operated to add a rod to the tail string 112. Due to the automatic and momentary nature of the freewheel suspend mode, the freewheel suspend mode is differentiated from normal drive mode. Even though the rotary drive unit 116 is enabled and used for limited driving during the freewheel suspend mode, the rotary drive unit 116 is only operable on the final drill rod, not the entire tail string 112, and the HDD machine 100B otherwise remains “set” to the freewheel mode since the suspend mode is an automatic subroutine that occurs when the HDD machine 100B is set to the freewheel mode.
While in the freewheel suspend mode, the operator will add a drill rod to the tail string 112. After a drill rod is added, it will be natural for the operator of the second HDD machine 100B to release the vise 520. This release of the vise 520 will trigger the control system 400 to automatically initiate a transition to the freewheel mode (i.e., freewheel mode no longer suspended). The transition can cease the drive capability of the freewheel suspend mode to return to freewheel mode. Once the second HDD machine 100B is back in freewheel mode, the pullback process can be restarted. As was noted previously, the rotary drive unit 116 should not be rotated while the machine is transitioning into the freewheel mode. Thus, the process of switching from the freewheel suspend mode back to the freewheel mode, includes a transition phase during which there is a clear indication for the operator of the second HDD machine 100B. After the vise 520 is released, the control system 400 includes a display that informs the operator that the machine is in a transition phase, during which neither the first nor the second HDD machines should be operated. After completing a process defined by logic in the controller 200, such as after a predetermined period of time after the vise 520 is released, or after confirmation that certain measured machine parameters meet predetermined levels, the display will change to inform the operator that the second HDD machine 100B is in the freewheel mode, and the first HDD machine 100A can safely re-start the pullback process. The transition phase is indicated to the operator with the display 302 that was previously intermittently displaying a symbol “L” now intermittently displaying or flashing the symbol “N”. After a predetermined time, and/or after confirming feedback signals from system, the system will indicate that it is safely in the freewheel mode by displaying a solid “N” illuminated in green. Once that mode is confirmed, the operator of the second HDD machine 100B will communicate with the operator of the first HDD machine 100A, and the pullback process will be restarted.
From the above discussion, it should be appreciated that the transition phase occurs whenever the HDD machine 100B is actually entering the freewheel mode, and not necessarily in response to the operator selecting the freewheel mode. For example, the transition occurs when the control system 400 automatically changes from freewheel suspend back into freewheel mode. Furthermore, when the operator selects the freewheel mode while the vise 520 is clamped, the HDD machine 100B will automatically enter the freewheel suspend mode instead of the freewheel mode—without requiring the above-described transition phase and notification. Instead, the transition phase and subsequent attainment of the freewheel mode are triggered when the vise 520 is determined to be released and the machine remains set to the freewheel mode.
The control system 400 includes a display device 300 for communicating the status of the machine to an operator, an operator input device 310 such as the button 312 for allowing an operator to select modes of operation, and control algorithms for operating the rotary drive unit 116 to selectively freewheel in coordination with other control systems of the HDD machine, to automate and coordinate various operations. The control system 400 coordinates operations in order to:
One example of inappropriate operation is when an operator would allow the pilot side HDD machine 100A to rotate the drill string 104, and thus the tail string 112, before the exit side HDD machine 100B is completely in the freewheel mode. If this inappropriate operation occurs, and the motor 130 at the exit side HDD machine 100B is forced to rotate, the pistons will contact the cam-ring in a way that can result in damage to the motor 130. This inappropriate operation can result from the operator not waiting long enough to allow the hydraulic control system to close the ball valves 168, 170 and to allow the case pressure to force the pistons inward. The processes associated with moving the linkage 216 to close the ball valves 168, 170 and with the hydraulic system to affect the charge pressure and the case pressure, takes some time, it can take up to four to five seconds, or more, to switch from operating mode to freewheel mode. The systems of the HDD machine 100B that are changed during a switch in operating modes are not visible to an operator. Thus, the control system 400 acts to appropriately inform an operator of the mode of the HDD machine 100B.
In addition to generating information for the operator, to protect the components of the machine, the control system 400 may have another operating mode that is intended to remind the operator and any other workers or bystanders near the second HDD machine 100B, specifically that the HDD machine is in the freewheel mode, while an operator is not at the machine controls of a control station thereof. This may occur when the operator of the second HDD machine 100B leaves the operator station for any reason, while it is operating in the freewheel mode. In the freewheel mode, the second HDD machine 100B is configured to allow the first HDD machine 100A to rotate and pull the drill string 104. When the HDD machine 100B is operating in a normal mode, and when it is not connected to another machine, an operator presence system may result in interruption of machine functions when an operator is detected absent from the operator station. When the machine functions are interrupted, the components of the HDD machine 100B are prevented from moving. However, when in the freewheel mode, the second HDD machine 100B is intentionally in a mode where it is allowing some of its components, such as the output 136 of the rotary drive unit 116, to be passively moved (e.g., by torque from the first HDD machine 100A). This freewheeling mode and situation are unique and can call for a unique adaptation of conventional operator presence lockout controls.
A unique operator warning system has been developed to remind the operator that the HDD machine 100B is in the freewheel mode when the operator is no longer at the controls, and to inform any bystanders of this condition. This mode is herein described as the Lack of Operator Presence (LOOP) mode. The control system 400 includes the controller 200 with control logic that includes algorithms that monitor the mode of the HDD machine 100B and that monitors an operator presence sensor 404. In some constructions, the operator presence sensor 404 can be provided as a seat sensor configured to detect (e.g., by weight or deflection in the seat) whether the operator is seated at the control station having all the machine controls (e.g., in the cab of
This alternate mode for the joystick 512 can correspond to the freewheel mode of the rotary drive 116 (e.g., motor(s) 130 set in freewheel mode). Thus, the alternate mode for the joystick 512 can be triggered directly or indirectly by the operator input device for mode switching (e.g., the control button 312). Either in direct response to the control button 312 being operated to switch to freewheel mode, or upon suitable time delay or feedback confirming the freewheel setting, the controller 200 is programmed to change its response to the movement of the joystick 512. In particular, the joystick 512 transitions from being an adjustable speed control for the carriage 124 to being a force adjustment control for longitudinal force on the drill string (drill string here referring to the tail string 112 as well as the additional drill string 104 extending to the first HDD machine 100A) as well as the reamer 108. In the force-controlling mode of the joystick 512, longitudinal force applied by the carriage 124 to the drill string 104, 112 can be variably adjusted proportional to how far the joystick 512 is moved. For example, an amount of backward movement of the joystick 512 as shown in
Maintaining controlled tension on the drill string 104, 112 can help to maintain the predictable positioning of the drill string and reamer 108 in the borehole. Controlled tension also may help maintain the tail string 112 out of contact with the open vises 520 at the forward end of the second HDD machine 100B as the drill string 104, 112 is moved under the influence of the first HDD machine 100A. In fact, the operator may visually observe the position of the tail string 112 with respect to the open vises 520 when deciding how much drill string tension to apply through movement of the joystick 512. In some constructions, in order to guarantee some amount of drill string tension applied by the carriage 124 of the second HDD machine 100B, or at least prevent the application of any longitudinal compression, movement of the joystick 512 from the center position forward can be ignored by the controller 200. In other words, forward joystick positioning of any amount can simply correspond to zero or the minimum tension setting. In some constructions, the carriage drive control system 500 can apply a brake, internal to the motor 504 or separate therefrom, when the joystick 512 is not activated to control drill string longitudinal force (e.g., when the joystick 512 occupies the center position, and optionally also when moved forward). The operator display 300 can be coupled to the carriage drive control system 500 to display to the operator a measure of the longitudinal drill string force. For example, the force value itself may be displayed, hydraulic pressure in the carriage drive unit, and/or a percentage corresponding to the range of allowable values from the minimum (e.g., zero) value to the maximum allowable value.
In a separate embodiment, a second range of movement of the joystick 512 (e.g., forward movement from the center position as shown in
In the case of zero longitudinal force setting for the AUTO mode, the carriage drive control system 500 can be configured to monitor the position of the gearbox 134 with respect to a gearbox slide 538. The gearbox slide 538 is a portion of the carriage 124 that provides a limited amount of free movement for the gearbox 134, which movement is required to accommodate the longitudinal component of movement during a drill rod attachment or detachment process (threading or unthreading). Thus, the gearbox 134 generally shifts forward in the slide 538 when the drill string is tensioned (
Aspects of the disclosure, including the structures and methods of operation described above and illustrated in the drawings are not limited to the explicit nature of this disclosure. For example, the freewheel mode may be included in an entry side HDD machine (e.g., the first HDD machine 100A), and application may also be found for aspects or portions of the disclosure outside of the field of horizontal directional drilling.
Various features of the disclosure are set forth in the following claims.
This application claims the benefit of priority to co-pending U.S. Provisional Patent Application No. 63/331,318, filed Apr. 15, 2022, co-pending U.S. Provisional Patent Application No. 63/324,408, filed Mar. 28, 2022, the entire contents of all of which are incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 63331318 | Apr 2022 | US | |
| 63324408 | Mar 2022 | US |
