FIELD
This invention relates generally to underground construction and to auger-boring excavation in particular.
SUMMARY
The present invention is directed to a boring machine. The boring machine comprises a frame, a cutting head, an auger, and an electric motor. The cutting head is rotationally attached to the frame. The auger is rotatably attached to the frame and the cutting head. The electric motor rotates the auger relative to the frame in response to a current, wherein the electric motor comprises a motor controller. The electric motor rotates the auger at a first rate when the current is at a first value and wherein the motor controller generates a signal when a rotation rate of the auger is interrupted.
A method for installing a pipe. The method comprises providing a current to a motor such that the motor rotates an auger and cutting head, thrusting the auger and the cutting head into a subsurface, conveying removed subsurface from the cutting head with the auger, and receiving torque pulses from the auger at the motor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a boring machine of the present invention, showing the machine in a launch pit.
FIG. 2 is a partial perspective view of the boring machine of FIG. 1, showing a cutter head and a product casing.
FIG. 3 is a sectional view of the boring machine with a rotating auger and a secondary internal casing within the product casing.
FIG. 4 is a detailed view of a cutting head for use with the boring machine of the present invention.
FIG. 5 is a top perspective view of a frame, carriage and motor assembly for use with the boring machine of the present invention.
FIG. 6 is a bottom perspective view of the frame of FIG. 5.
FIG. 7 is a back perspective view of the frame of FIG. 5.
FIG. 8 is a side perspective view of the frame of FIG. 5 with a push plate and adjustable casing adaptor.
FIG. 9 is a diagrammatic representation of a six phase switch reluctance motor for use with the boring machine of the present invention.
FIG. 10 is a diagrammatic representation of an electric motor system for use with the boring machine of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, boring machine 10 is located in launch pit 12 and is shown as it would appear in the process of boring tunnel 14. Boring machine 10 comprises a carriage 16 which is mounted on and adapted to move along a track 18 in boring direction D. The carriage includes an electrically powered motor 20 for operating a selected one of a plurality of cutter heads, such as cutter head 22, and pusher mechanism 24 for pushing or driving the carriage along the track 18 in direction D.
With reference to FIG. 2, boring machine 10 (FIG. 1) also comprises a plurality of steering heads, including steering head 30, and is intended for use in simultaneously boring a tunnel and installing any of a plurality of product casings 32 in the tunnel. Each product casing 32 is joined together end to end. Each cutter head 22 and steering head 30 is selected to correspond to the diameter of the tunnel 14 (FIG. 1) to be bored and to the diameter of the selected product casing 32 to be installed. Preferably, the steering head 30 is welded to the front end of the product casing 32 and the cutter head 22 is welded to the front end of the steering head, though other attachment methods may be utilized. In FIG. 2, the product casing 32 has an outer diameter less than the diameter of the cutter head 22.
As shown in FIG. 3, the boring machine 10 comprises an internal casing 34 with an outside diameter OD34 less than the inside diameter ID32 of the product casing 32. This is an alternative arrangement for an auger boring machine first disclosed in U.S. Pat. No. 8,210,774, issued to Vidovic, the contents of which are incorporated herein by reference. Preferably, internal casing outside diameter OD34 is no more than about 60% of the ID32 of the product casing 32 having the smallest product casing inside diameter. Internal casing 34 is adapted to be placed within the product casing 32 so that the internal casing longitudinal axis coincides with longitudinal axis A (FIG. 3) of the selected product casing. Legs 35 may be utilized between the product casing 32 and the internal casing 34 to maintain a constant distance between the product casing and internal casing.
Thus, the preferred boring machine includes a plurality of sets of cutter heads 22 and steering heads 30 for use in connection with a plurality of differently-sized product casings 32. The outside diameter of the cutter head 22 and steering head 30 in each set may correspond or be larger than to the outside diameter of the selected product casing 32 to be installed.
An annular space 36 shown in FIG. 3 will be formed between the internal casing 34 and the product casing 32. Hydraulic lines, cables and wiring for the cutter head and steering head (not shown in the drawings) are placed within this annular space 36 and protected from contact with the tunnel 14 (FIG. 1) walls and from contact with material cut by the cutter head 22 as boring is carried out. Alternatively, such lines and wiring may be placed within a hollow cavity (not shown) in the auger 40.
The boring machine 10 also includes a material conveyor such as auger 40 that is located within the internal casing 34. Auger 40 has front end 42 and rear end 44. The motor 20 (FIG. 1) is operationally connected to the auger 40. The auger 40 rotates with respect to internal casing 34, so that operation of the rotational mechanism will cause the auger to convey material within the internal casing 34 towards the rear end 44 of the auger. Simultaneously with rotation of the auger 40, the pusher mechanism 24 (FIG. 1) drives the carriage 16 along the track 18, advancing the cutter head 22, steering head 30, auger 40, product casing 32 and internal casing 34 along boring direction D. One of skill in the art will appreciate that in auger boring machines 10 without a separate internal casing 34, the auger 40 will be within the product casing 32.
The boring machine 10 includes a front bulkhead 46 adapted to be located around the internal casing behind the selected cutter head and in front of the adjacent steering head. The front bulkhead 46 prevents material cut by the cutter head from getting into annular space 36. One of ordinary skill will appreciate that a plurality of different front bulkheads 46 may be utilized to size to the product casing 32.
The boring machine 10 comprises a means for directing material cut by the selected cutter head 22 into the internal casing 34 so that rotation of the auger will convey such material towards the rear end 44 of the auger 40 within the internal casing 34. As best shown in FIG. 4, cutter head 22 includes a plurality of cutter blades 50, each of which has front side 52 and rear side 54. The cutter blades 50 are operationally attached to the auger 40 (FIG. 3), either directly or through a linkage mechanism (not shown), so that rotation of the auger will also rotate the cutter blades. In this embodiment of the invention, the means for directing material cut by the cutter blades of the selected cutter head 22 into the internal casing comprises a plurality of collecting buckets 56, each of which is mounted on the rear side 54 of a cutter blade 52. These collecting buckets 56 sweep material cut by the cutter blades 52 into hopper 58 through hopper opening 60 as the cutter blades rotate. Hopper 58 may comprise an extension of internal casing 34 or product casing 32 and includes front end 42 of auger 40 (FIG. 3).
With reference now to FIG. 5, the boring machine 10 and carriage 16 are shown in more detail. The boring machine 10 comprises a dog box 100, or frame, which is located in launch pit 12 (FIG. 1). The dog box 100 supports the track 18. The carriage 16 moves along the track 18 during thrust of the cutting head 22. The carriage 16 supports an electric component motor 104, an electric motor 20 to rotate auger 40, and actuators 106. Because electric motor 20 rotates the auger 40, it also rotates the cutting blades 50 (FIGS. 3-4) disposed at the first end 42 of the auger. The electric component motor 104 powers the actuators 106. The electric component motor 104, as shown, activates a pump or pumps 107 with pressurized hydraulic fluid for use in actuators 106. Alternatively, the electric component motor 104 itself may provide motive force for various mechanical linear actuators. The linear actuators 106 each comprise part of the pusher mechanism 24 (FIG. 1), which comprises sprocket drives 108 either powered directly, or by hydraulic pumps 107. The sprocket drives 108 rotate sprockets 120 (FIG. 6), translating the carriage 16 along the track 18. The actuators 106 may further comprise thrusters 109, such as hydraulic cylinders or mechanical actuators for thrusting the carriage 16 and the cutting head 22 (FIG. 4).
The thrusters 109 in particular, and the pusher mechanism 24 (FIG. 1) in general are able to be manipulated precisely by the variable output allowed by electric motor 104.
The electric motor 20 may comprise a planetary reduction 110 for altering the gear ratio between the electric motor 20 and the auger 40 (FIG. 5). An electric motor may have variable speeds responsive to current frequency. Therefore, unlike conventional combustion engines, a gearing transmission is not required to change rotation speed of the auger 40. The power source for the electric motor 20 and the electric component motor 104 may be an alternating current source, such as a power grid, or may be a direct current source, such as a generator or battery. The electric motor 20 and electric component motor 104 may comprise a variable frequency drive, allowing enhanced control of output. Control of motor output reduces the likelihood of machine upset and component failure due to over-torque.
The frame 100 further comprises a thrust plate 112 and a casing saddle 114. The thrust plate 112 provides a stable base for the thrust functions of the carriage 16. The casing saddle 114 supports the product casing 32 as it is thrust into the ground and can be adjusted to support product casing 32 (FIG. 2) having multiple diameters.
With reference now to FIG. 6 the boring machine 10 is shown from below. The sprocket drives (FIG. 5) rotate a plurality of sprockets 120 which comprise a plurality of teeth 124. Each of the plurality of teeth 124 interacts with a gap in the track 18 in a “rack and pinion” style motive connection. The track 18 may be supplied in separate track sections 126 connected by hinge bolts 128. The thrusters 109 shown in FIG. 6 are hydraulic cylinders. The thrusters 109 provide thrusting force to the auger 40 and cutter head 22 (FIG. 3), while non-thrusting translation of the carriage 16 relative to the frame 100 is carried out by rotation of the sprockets 120.
With reference to FIG. 7, the boring machine 10 is shown from the back. The frame 100 comprises an untracked portion 130 to enable the carriage 16 to be lowered into the track 18. The electric component motor 104 is shown as being located above the electric motor 20 on carriage 16, though other configurations may be utilized. Hydraulic pumps 107 and sprocket drives 108 may be combined, or eliminated in the case of electrically driven mechanical actuators (not shown).
With reference now to FIG. 8, the boring machine 10 is shown in perspective. The boring machine 10 further comprises a push plate 140, a casing adaptor 142, a barrel 144 and an auger connection 146. The push plate 140 is attached to the carriage 16 through the barrel 144. When the thrusters 109 (FIG. 6) extend, the carriage 16, barrel 144 and push plate 140 move toward the casing saddle 114 and away from thrust plate 112. The adjustable casing adaptor 142 may be attached directly to the push plate 140 by swivel pins 148 or other attachment means. The adjustable casing adaptor 114 connects to the product casing 32 (FIG. 2). Thus, thrust is generated by thrusters 109 (FIG. 6), transmitted through the barrel 144 to the push plate 140 and casing adaptor 142 such that the thrusters 109 exert thrust on the product casing 32 (FIG. 2). The casing saddle 114 may be adjusted to correspond to the particular adjustable casing adaptor 142 used.
The auger connection 146 provides a rotatable connection between the electric motor 20 and the auger 40 (FIG. 3). As shown, the auger connection 146 comprises a hexagonal cavity 149 for torque-transmitting connection with a mating coupling (not shown) on the auger. One of ordinary skill can appreciate that fluid lines, electric lines, a laser guidance system and other material (not shown) may travel through cavity 149 in the auger connection 146.
One particular electric motor 104, 20 that may be used is a switched reluctance motor of the type shown in U.S. Patent Publication No. 2012/0306297, Kim et al., the contents of which are incorporated herein by reference. In the Kim reference, a switched reluctance motor suitable for use as a rotation motor has twelve stator poles and ten rotor poles. The advantage of switch reluctance motors are that the electric motor 20 may receive torque reversal pulses from the auger 40—essentially feedback that the motor can interpret and use to adjust the rate of rotation. This minimizes the risk of an underground obstruction restricting rotation of the cutter head 22, causing the rotation of the motor 20 to rotate the boring machine 10 rather than the auger 40. As shown in FIG. 9, a switched reluctance motor 20 may have a double salient pole configuration, with twelve stator poles 200 and ten rotor poles 202. Torque control is accomplished by controlling the magnitude of the current in motor windings (not shown) and the timing of the rotor poles 202 relative to the stator poles 200.
Output speeds of the motor 20, 104 is controlled by the current provided to windings (not shown) about the poles 200, 202. Providing varying values such as current and frequency may vary the speed of the motor 20. For example, eight varying speeds and directions may be preferable. One of skill in the art will appreciate that obstructions underground may cause the rotation speed of the auger 40 to be interrupted or obstructed. The motor 20 receives this information as a “torque pulse” that changes the rotational rate between the poles 200, 202. This “pulse” is received by the motor 20 and causes the motor to alter rotation of the auger 40 by stopping the auger or slowing the rate of rotation. This decreases the likelihood that the frame 100 of the boring machine 10 will overturn as a result of the motor 20 attempting to turn an obstructed auger 40.
FIG. 10 is a diagrammatic representation of the power structure to provide current to motor 20. An engine, such as a diesel engine 300, drives a generator 302. The generator 302 provides three phase electric power to a diode bridge. Alternatively, an electric grid may be used to power motor 20. A rectifier 303 may be provided to convert current from AC to DC. In FIG. 10, a DC bus 304 provides direct current to motor 20 comprising a switch reluctance motor controller 307. The motor 20 is connected to a gearbox 308, which rotates to the planetary reduction 110 and the auger 40 (FIGS. 3 & 5). The motor controller 307 is adapted to receive torque pulses as described above and stop or slow rotation of the auger 40 (FIG. 3) in response to the same.
One of ordinary skill in the art will appreciate that a remote control 400, as diagrammatically represented in FIG. 8, either wirelessly or directly connected to the boring machine 10, may be advantageous. The remote control may allow for multiple auger 40 rotation speeds, such as eight speeds, in both rotational directions. RPM and torque, as defined at the control, may refer to the rotations of the auger 40 and cutting head 30, rather than of the auger rotation motor 20. A display may be provided, showing thrust, rotation speed, etc. Sensors may display the “end of stroke” for the thrust cycle of the linear actuators 106. The use of electric motors 104, 20 allow thrust and rotation to be finely tuned, and through use of a remote, an operator may be located away from the dog box 100.
The auger rotation motor 20 may comprise a hollow spindle 146 (FIG. 8) for laser targeting by the steering head 30 through the center of the auger 40. Additionally, attachments other than cutting head 22 may be utilized at the downhole end of auger 40, such as a pilot tube string. The pilot tube (not shown) may comprise laser-based targeting for the steering head 30.
Although this description contains many specifics, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the presently preferred embodiments thereof, as well as the best mode contemplated by the inventors of carrying out the invention. The invention, as described herein, is susceptible to various modifications and adaptations, as would be understood by those having ordinary skill in the art to which the invention relates, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
Patent Application
20160090831
