Boring or penetrating the earth – With magazine for successively moving unconnected – oriented...
Reexamination Certificate
2000-08-11
2003-05-06
Neuder, William (Department: 3672)
Boring or penetrating the earth
With magazine for successively moving unconnected, oriented...
C184S007300, C184S015300, C184S006000, C222S249000
Reexamination Certificate
active
06557651
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of underground boring and, more particularly, to a system and method of dispensing a lubricant to threaded joints between a drive spindle of a drilling machine and a drill rod being threaded or unthreaded with respect to the drive spindle.
In accordance with a general horizontal boring technique, also known as microtunnelling, horizontal directional drilling (HDD) or trenchless underground boring, a boring system is situated on the ground surface and drills a hole into the ground at an oblique angle with respect to the ground surface. A drilling fluid is typically flowed through the drill string, over the boring tool, and back up the borehole in order to remove cuttings and dirt. After the boring tool reaches a desired depth, the tool is then directed along a substantially horizontal path to create a horizontal borehole. After the desired length of borehole has been obtained, the tool is then directed upwards to break through to the earth's surface. A reamer is then attached to the drill string which is pulled back through the borehole, thus reaming out the borehole to a larger diameter. It is common to attach a utility line or other conduit to the reaming tool so that it is dragged through the borehole along with the reamer.
In order to increase the length of the drill string during a boring operation, drill rods are situated in a carriage of the HDD machine and individually threaded onto to the drill string using a spindle or drive chuck powered by a rotation motor of the HDD machine. In order to decrease the drill string length, such as during a backreaming operation, individual drill rods are unthreaded from the drill string and removed from the carriage.
It can be appreciated that the above-described threading and unthreading operations introduce stress and heat into the threaded joint interface between the spindle and drill rod. If sufficient lubricity is not present a
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t the threaded joint interface, several undesirable results may occur. For example, excessive heat and friction generated at the threaded joint interface may cause premature wear on the spindle/drive chuck/drill stem. Threads of the spindle and those of a drill rod may bind together due to excessive heat, pressure, and torque. Such binding at the threaded joint interface may create a weld characteristic, thereby limiting the ability to disjoint the rod. The inability to disjoint a rod can ultimately cause failure of the boring operation.
Conventional manual approaches to applying a lubricant, such as grease, to the threaded joint interface are time consuming, labor intensive, cumbersome, and typically unpleasant. Although some degree of automation has recently been proposed, such proposed approaches are fairly crude and fail to take into account operational factors such as ambient and drilling machine temperatures, rate of spindle rotation during threading and unthreading operations, and control of lubricant application rates and volumes.
There exists a need in the excavation industry for an apparatus and methodology for automating the delivery of a lubricant to a threaded joint interface between a spindle and drill rod when making or breaking a threaded joint. There exists a further need for such an apparatus and methodology which optimizes the automatic application of a lubricant to a threaded joint interface. The present invention fulfills these and other needs.
SUMMARY OF THE INVENTION
The present invention is directed to a lubrication system for dispensing a lubricant to threads of a drill rod and/or a spindle of a horizontal directional drilling (HDD) machine during a rod loading or unloading operation. A lubrication system of the present invention includes a pumping system having a lubricant reservoir, a pump, an applicator, and a lubricant supply conduit coupled between the pump and applicator. A control unit is coupled to the pumping system. The control unit, in response to an operator signal or an HDD machine control signal, activates the pumping system to dispense a volume of lubricant from the applicator to the threads of the drill rod and/or spindle. The control unit may control the pumping system to dispense the lubricant substantially over a circumferential surface of the threads of the spindle and/or drill rod.
A heating unit may be coupled to the pumping station and heats lubricant contained within the pumping system. A heating unit may, in addition or in the alternative, be coupled to the applicator, in which case the heating unit heats lubricant within the applicator.
The heating unit includes an inlet port and an outlet port. The heating unit receives a thermal transfer fluid from the HDD machine via the inlet port and returns the thermal transfer fluid to the HDD machine via the outlet port. In one embodiment, the heating unit is coupled to a gearbox of the HDD machine. The heating unit receives a thermal transfer fluid from the gearbox via the inlet port and returns the thermal transfer fluid to the gearbox via the outlet port. The heating unit may be controlled by the control unit to vary a viscosity of the lubricant.
In accordance with another embodiment, the heating unit is coupled to an engine coolant system of the HDD machine. The heating unit receives a thermal transfer fluid from the engine coolant system via the inlet port and returns the thermal transfer fluid to the engine coolant system via the outlet port. According to a further embodiment, the heating unit is coupled to a source of electrical power provided on or external to the HDD machine. The heating unit generates heat to heat lubricant within the pumping system in response to a current received from the electrical power source.
The heating unit may further include a first heat transfer unit coupled to the pumping system to heat lubricant within the pumping system and a second heat transfer unit coupled to the applicator to heat lubricant at the applicator. In another embodiment, the heating unit includes a first heat transfer unit coupled to the pumping system to heat lubricant within the pumping system and a third heat transfer unit coupled to the lubricant supply line to heat lubricant within the lubricant supply line.
The pumping system is provided with power supplied by the HDD machine or power source external to the HDD machine. The pumping system may be provided with hydraulic or pneumatic power supplied by the HDD machine. The pumping system may alternatively be provided with electric or mechanical power from the HDD machine. In one embodiment, the pumping system is provided with hydraulic power supplied by one or both of a rotation pump or a displacement pump of the HDD machine.
The pumping system dispenses a fixed volume of lubricant through the applicator according to an embodiment of the invention. The control unit may produce a control signal to vary a rotation rate of the rod and/or spindle, and the pumping system may dispense a fixed volume of lubricant through the applicator at a variable dispensing rate during a time in which the rotation rate of the rod and/or spindle is varied.
In one embodiment, the control unit, in response to a rotation rate of the rod and/or spindle, adjusts one or more characteristics of the pumping system to dispense a desired volume of lubricant to all or selected portions of a thread of the rod and/or spindle. In another embodiment, the control unit controls a duration of dispensing produced by the pumping system during a time in which the spindle and rod are threaded together, such that the dispensing time is proportional to a rotation rate of the spindle and/or rod.
The applicator, according to one embodiment, includes a nozzle. The nozzle may include an orifice that varies in one or both of size or shape. The nozzle has an associated adjustable spray pattern. The control unit may adjust one or both of a cross-sectional width of the spray pattern or a length of the spray pattern. The pumping system may be an airless pumping system.
A cleaning apparatus may further be provided that clea
Austin Gregg A.
Bischel Brian J.
Erickson Steven
Norby Duane E.
Rempe Scott A.
Crawford & Maunu PLLC
Neuder William
Vermeer Manufacturing Company
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