US3835942A

US3835942A - Earth boring device

Info

Publication number: US3835942A
Application number: US00346714A
Authority: US
Inventors: S Leonardi
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-03-30
Filing date: 1973-03-30
Publication date: 1974-09-17
Anticipated expiration: 1991-09-17
Also published as: CA980334A

Abstract

Earth boring device for sinking a well casing in which a housing rotates within the well casing, the housing carrying circumferentially spaced, diametrically disposed, cutters which excavate an annular bore below the well casing. The cutters are capable of being moved to a position radially inward of the well casing, permitting the raising of the housing from the bottom of the excavated well within the well casing.

Description

451 Sept. 17, 1974 United States Patent [191 Leonardi 2,874,936 2/1959 Gonzales.................i....... 175/171 X 2,925,252 2/1960 EARTH BORING DEVICE Minor 12/1964 Davis t td SNL Primary ExaminerDavid H. Brown Attorney, Agent, or FirmHarry N. Schofer 22 Filed: Mar. 30, 1973 21 Appl. No.: 346,714

[57] ABSTRACT Earth boring device for sinking a well casing in which a housing rotates within the well casing, the housing carrying circumferentially spaced, diametrically disposed, cutters which excavate an annular bore below the well casing. The cutters are capable of being l 7 l l l 2 6 mwo w n 7 m fi l a n 7 unlm mh a n a u "S L h C G .M mm

I U E 1 1: 2 l 8 5 l .l 1

moved to a position radially inward of the well casing, References Cited permitting the raising of the housing from the bottom UNITED STATES PATENTS of the excavated well within the well casing.

1,315,422 Roberson........................ /104 X 20 Claims, 22 Drawing Figures TFr 'Tr 1 Illlllllll 1 LLLLLLLLLL TENTH} SEP I 7 1974- EARTH BORING DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the art of earth boring, and more particularly to a device for sinking a well casing.

2. Description of the Prior Art In the sinking of well casings, the usual practice involves the drilling of the well to its desired depth, and then sinking the well casing as a separate operation. This presents no particular problem in drilling through hard earth formations, but in gravel or soft and/or loose earth formations, a different situation exists.

SUMMARY OF THE INVENTION It is an object of this invention to provide a novel earth boring device in which the earth is bored and the well casing is placed in position in a simultaneous operation.

It is a further object to provide a novel earth boring device in which an annular bore is excavated in a continuous operation immediately below the well casing, permitting the insertion of the casing to follow the drilling operation.

It is a still further object to provide a novel earth boring device which is operable in all types of earth formations, and particularly in loose earth and/or gravel formations.

It is a still further object to provide a novel earth boring device which is rotatable within a well casing and is readily removable for servicing or for any other purpose.

The attainment of the above objects including other objects and advantages is accomplished by a novel earth boring construction in which an earth boring housing is rotatably mounted within a well casing. The well casing is fitted, on its interior wall near the lower end, with a ring gear. The housing includes one or more motor driven pinions engageable with the ring gear, causing rotation of the housing within the casing when the motors are operated. Obviously, means are provided at the surface to prevent rotation of the well casing. The housing carries cutting means which may be extended to an earth cutting position immediately below the well casing, whereby the rotating movement of the housing causes the cutting means to excavate an annular bore, the excavated earth being moved toward the center whence it is removed by various means. Other means are provided to excavate the earth within the annular bore. In order to remove the earth boring device for any purpose, the cutting means may be retracted from its cutting position below the well casing and the earth boring means may readily be lifted from its position at the bottom of the well excavation.

Several forms of the invention are provided, and are described in detail below. In one form of the invention the cutting means comprise one or more diametrically disposed cutters, each cutter rotatable about a vertical axis and driven by an independent motor, the cutters being carried by the housing and revolving about the axis of the rotating housing.

In a second embodiment of the invention the cutting means comprise one or more pairs of diametrically disposed, rotatable, cutters mounted for extension to a position below the well casing and retraction to a position within the well casing.

In a third embodiment of the invention, the cutting means comprise one or more pairs of diametrically disposed, radially extending, cutters which may be extended to a cutting position below the well casing, or retracted to a position within the well casing permitting the earth boring device to be raised from its operating position within the well casing.

In a fourth embodiment of the invention, the cutting means comprise one or more pairs of diametrically disposed, rotatable, cutting means, each cutting means including one or more cutters rotatable on an axis that is radially disposed relative to the rotatable housing, each cutter being pivotally mounted for selective movement from a first position in which it is swung inwardly to an inoperative position within the well casing, to a second position in which it is swung outwardly below the well casing and in which pinions, carried by the cutters, engage an annular gear on the lower end of a stationary member connected with the well casing, wherby the rotation of the housing causes the cutters to revolve and to rotate to excavate an annular bore below the well casing.

In a fifth embodiment of the invention the cutting means comprise one or more pairs of diametrically disposed cutters, each cutter consisting of a plurality of interconnected cutting blades connected with the housing and guided in their movement by a track carried by a stationary member disposed between the well casing and the housing, the track having an opening permitting the cutters, when extended to an operative position, to be received in the track, where rotation of the housing will cut an annular excavation below the well casing, and retracted to be removed from the track to an inoperative position within the well casing.

BRIEF DESCRIPTION OF THE DRAWINGS For a clearer understanding of the invention and its operation, reference is made to the following detailed description of five preferred embodiments, and to the annexed drawings, in which:

FIG. 1 is a vertical sectional view of a first embodiment;

FIG. 2 is a top end view taken along the line 2--2 of FIG. 1;

FIG. 3 is a partial sectional view taken along the line 33 of FIG. 1;

FIG. 4 is a bottom end view taken along the line 44 of FIG. 1;

FIG. 5 is a vertical sectional view of a second embodiment of the invention, taken on the line 5-5 of FIG. 6;

FIG. 6 is a bottom end view, as seen along the line 66 of FIG. 5;

FIG. 7 is a verticl sectional view taken along the line 7-7 of FIG. 8;

FIG. 8 is a top view of a part of the device, taken along the line 8-8 of FIG. 7;

FIG. 9 is a vertical sectional view of a third embodiment of the invention, taken along the line 99 of FIG. 10;

FIG. 10 is a bottom end view, as seen along the line l0l0 of FIG. 9;

FIG. 11 is a horizontal sectional view taken along the line 11-11 of FIG. 9;

FIG. 12 is a vertical sectional view through a fourth embodiment of the invention;

FIG. 13 is a bottom end view of the device shown in FIG. 12 as seen on the line 13-13 of FIG. 12;

FIG. 14 is an enlarged sectional view of the cutting means shown in FIG. 13;

FIG. 15 is a sectional view through the cutting means, taken on the line 15-15 of FIG. 14;

FIG. 16 is an enlarged view of the cutting means;

FIG. 17 is a horizontal sectional view taken on the line 17-17 of FIG. 12;

FIG. 18 is a vertical sectional view through a fifth embodiment of the invention;

FIG. 19 is a horizontal sectional view taken along the line 19-19 of FIG. 18;

FIG. 20 is a bottom end view as seen along the line 20-20 of FIG. 18;

FIG. 21 is a horizontal sectional view through a portion of the guide, taken along the line 21-21 of FIG. 22; and

FIG. 22 is an elevation view of a portion of the guide in the bottom end of the well casing.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Referring to FIGS. 1, 2, 3, and 4, illustrating a first embodiment of the invention, the numeral 10 designates the earth boring device in its entirety, shown in its boring position within a well casing 12.

The earth boring device 10 comprises a hollow housing 14 including an upper circular deck 16 atop a cylindrical side wall 18, the lower end of which includes a pair of diametrically disposed inturned lobes 20 carrying a pair of bearings 22. The lower end of the housing 14 is closed by a cone-shaped member 24 connecting at its apex with the lower end of a tubular member 26 which extends through the hollow housing and upper deck 16, terminating a short distance above the deck for a purpose to be set out later in this disclosure.

An internal flange 28 is formed intergrally with the well casing 12 a short distance above the bottom end thereof, and forms a limiting stop for an external flange 20 formed integrally with the cylindrical side wall 18 of the hollow housing 14. Situated above the flange 28 of the well casing 12 and slightly above the upper deck 16 of the hollow housing 14, an internal ring gear 32 is formed integrally with the well casing 12.

Referring to FIGS. 2 and 3, a pinion means comprising a first gear 34, supported for rotation above the upper deck 16, meshes with the teeth of the internal ring gear 32. A second gear 36 meshes with the first gear 34, the second gear 36 being connected with and driven by a motor 38 disposed within the hollow housing 14. It is evident that rotation of the second gear 36 by the motor 38 causes rotation of the hollow housing 14 within the well casing 12. The motor 38 may be of any well known type, either electric or fluid, and may be connected to be driven through electrical conductors or fluid conductors (gaseous or hydraulic), the particular connections not being illustrated as being well known in the art and forming no part of the invention.

Cutting means, comprising a pair of diametrically disposed cutters 40, each mounted on a vertical shaft 42 for rotation in the bearings 22 in the inturned lobes 20 and in aligned bearings 43 in the upper deck 16, are of a length and form to cut an annular groove or channel through the earth formation below the well casing 12 as the cutters 40 are rotated about the axes of the shafts 42 and revolved about the vertical axis of the hollow housing 14.

As seen in FIG. 4, each of the cutters 40 includes a pair of diametrically opposed cutting elements. The cutters 40 are secured at the lower end of shafts 42, each shaft having a sprocket wheel 44 disposed within the hollow housing 14, adapted to be driven by a chain drive 50 and a sprocket wheel 46 on the shaft of a motor 48.

An annular collector wall 52 projects upwardly from the deck 16 to a point slightly above the upper end of the tubular member 26, as shown in FIG. 1.

A centrally disposed auger 54 projects downwardly from the hollow housing 14, being supported by an excavating means 56 comprsing a plurality of radially disposed cutting blades, each blade being disposed at an angle to cut the earth formation and to force the detritus upward through the cone-shaped member 24 and the tubular member 26 to spill over the upper end of said member 26 to be collected within the chamber formed by the collector wall 52.

A lifting cable 58 is attached to the upper end of the collector wall 52 to lift the earth boring device to the surface when it is desired to empty the contents from the chamber formed by the collector wall 52, or for any other purpose.

In operation, the well casing 12 and the earth boring device 10 are simultaneously lowered. The flange 30 of the earth boring device 10 and the flange 28 of the well casing 12 are designed so that the flange 30 rests atop the flange 28 to limit the downward movement of the earth boring device 10 relative to the movement of the well casing 12. In this position, the teeth of the gear 34 mesh with the teeth of the ring gear 32 so that, when the motor 38 is actuated, the hollow housing 14 rotates within the well casing 12, causing the rotation of the cutting blades of the excavating means 56 to cut into and excavate the earth formation below the earth boring device 10. At the same time, the motor 48 is actuated, causing rotation of the cutters 40, and as the housing 14 rotates, the cutters 40 revolve to cut an annular channel, forcing the detritus inwardly toward the center to be forced upwardly to discharge through the upper end of the tubular member 26.

As seen in FIGS. 1 and 4, the diameter of the earth removed by the cutters 40 and excavating means 56 is greater than the external diameter of the well casing 12, permitting the well casing to easily follow the downward movement of the earth boring device 10. The revolving motion of the rotating cutters 40 causes the cutters to travel in a generally helical downward motion, and since the two cutters 40 are diametrically disposed, there will always be a higher level of unexcavated earth immediately below the lower end of the well casing 12, thus preventing the well casing from resting on the cutters 40.

The auger 54 serves as a centering device, and also as a means to break into any rock formation that may be encountered.

When it is desired to raise the earth boring device 10 for any desired reason, the motor 48 is stopped in a position in which the cutters 40 occupy the position shown in broken lines in FIG. 4, which permits the raising of the earth boring device 10 without the danger of the cutters 40 engaging either the internal flange 28 or the ring gear 32 carried by the well casing.

While only one pair of cutters 40 is shown, it is evident that more than one pair of cutters can be utilized. It is preferred, when more than one pair is provided, that they be diametrically disposed and angularly spaced at equal distances to give balanced operation.

The well casing 12 can be made in desired lengths, with additional lengths added and securely fastened to the next lower length as the well casing is being lowered, in an obvious manner.

A second embodiment of the invention, in which the cutters are mounted for extension and contraction, is illustrated in FIGS. 5, 6, 7 and 8. In this embodiment, the earth boring device is designated in its entirety by the numeral 64, and the well casing is designated by the numeral 66.

The earth boring device comprises a hollow housing 68 having an upper deck 70, a cylindrical side wall 72, and a bottom wall 74 which merges into a cone-shaped member 76. A tubular member 78 connects with the apex of the cone-shaped member 76 and extends through the housing 68 and upper deck 80 to a point spaced slightly above the deck, as illustrated in FIG. 5.

The well casing 66 includes an integral internal flange 80 a short distance from the bottom thereof, which is adapted to support an external flange 82 integral with the side wall 72 of the housing 68, and spaced about midway between the deck 70 and the bottom wall 74. Spaced above the internal flange 80, the well casing 66 includes an internal ring gear 84, which is disposed relative to the internal flange 80, to be approximatley in line with the upper deck 70 when the external flange 82 comes to rest on the internal flange 80, as shown in FIG. 5.

A pinion means, comprising a gear 86, is mounted above the upper deck 70 on a shaft passing through the deck and driven by a motor 88 disposed below the deck, the gear meshing with the internal ring gear 84. Operation of the motor 88 will cause rotation of the earth boring device 64 within the well casing 66 in an obvious manner. The motor 88 is mounted within a recess 90 formed in the side wall 72, and is driven through conventional electrical conductors or pressure fluid conduits in a manner well known in the art and forming no part of the present invention.

Referring to FIGS. 5 and 6, the earth boring device also includes cutting means, comprising at least one pair of diametrically disposed cutters 92 mounted for rotation adjacent the periphery of the hollow housing 68 on the end of a pair of shafts 96 connected to be driven by a pair of motors 94 disposed within the interior of the hollow housing 68, the shafts 96 extending through radially elongated slots 100 in the bottom wall 74. The motors 94 are attached to the ends of a pair of shafts of servo-motors 98, whereby actuation of the servomotors is effective to radially extend or retract the motors 94 and the cutters 94 connected thereto.

A collector wall 102 extends upwardly from the periphery of the upper deck 70 to a point a short distance above the upper end of the tubular member 78, as seen in FIG. 5. The collector wall 102 includes a recess 104 to receive the gear 86.

Excavating means comprising a plurality of cutting blades 108, disposed an an angle, extend below and across the base of the cone-shaped member 76, the blades supporting an axially disposed auger 106.

A lifting cable 1 10 is attached to the upper wall of the collector wall 102 to raise and lower the earth boring device 64 within the well casing 66.

In operation, the well casing 66 and the earth boring device 64 are simultaneously lowered. The earth boring device 64 is lowered within the well casing 66 until the external flange 82 comes to rest on the upper surfaces of the internal flange of the well casing, permitting the gear 86 to mesh with the teeth of the internal ring gear 84. During this operation of lowering the earth boring device 64, the cutters 92 have been retracted radially inwardly, to permit the cutters to pass clear of the internal ring gear 84 and the internal flange 80. When the earth boring device has been lowered, the servomotors 98 are actuated to extend the motors 94 and the cutters 92 to the position shown in FIG. 5. Actuation of the

motors

88 and 94 causes the earth boring device to rotate about its vertical axis, and the cutters 92 to rotate about the vertical axis of the shafts 96 and to revolve about the vertical axis of the earth boring device 64. As the cutters 92 rotate and revolve, an annular channel is being cut below the well casing 66, and the excavated earth is being moved toward the center to be removed by the cutting blades 108 which, during the rotation of the earth boring device, cut the earth within the annular channel, and remove all of the detritus upwardly through the cone-shaped member 76 and the tubular member 78 to spill over into the receiving space formed by the collector wall 102. As the cutters 92 revolve and rotate, they proceed downward following a helical path, followed by the well casing 66 which, because of the helical path, always rests on solid, unexcavated, earth above the level of the cutters 92.

The auger 106 provides a pilot hole, breaking any rock formation that may be encountered, and centers and stabilizes the earth boring device 64.

The earth boring device 64 can be raised by the cable 110 to remove the detritus collected within the collector wall 102, or for any other purpose.

As in the previously described embodiment, the well casing 66 can be lowered in sections, each section being secured to the section immediately below. It is evident that means must be provided to prevent the well casing 66 from rotating during the earth boring operation.

While only one pair of cutters is described, it is evident that more than one pair, each pair being diametrically disposed, can be utilzed.

A third embodiment of the invention is illustrated in FIGS. 9, l0 and 11. This embodiment employs different cutters, excavating means, and detritus removing means.

Referring to FIGS. 9 and 10, there is illustrated an earth boring device designated in its entirety by the numeral disposed within a well casing 122.

The earth boring device includes a hollow housing 124, illustrated as being circular in cross section and having an external diameter slightly less than the internal diameter of the well casing 122. The housing 124 comprises a circular upper deck 126, a cylindrical side wall 128 and a bottom wall 130. A cone-shaped member 132 extends upwardly from the center of the bottom wall and merges into a tubular member 134 which extends upwardly through the upper deck 126 to a discharge point above the surface of the earth being excavated.

The well casing carries an integral internal flange 136 above the bottom end to cooperate with an external flange 138 on the side wall 128, as shown in FIG. 9. The well casing also carries an internal ring gear 140 disposed slightly above the internal flange 138, the flanges and the ring gear being relatively disposed so that, when the flange 138 rests on the flange 136, the upper deck 126 occupies a position slightly above the bottom end of the ring gear 140. Pinion means, including a gear 142 meshing with the teeth of the ring gear 140, is mounted on the end of a shaft passing through the upper deck 126 and driven by a motor 144 located within the hollow housing 124. The motor 144 may be of the pneumatic, hydraulic, or electric type. Operation of the motor 144 will cause rotation of the earth boring device 120 in an obvious manner.

Diametrically disposed cutting means, comprising a pair of radially extending cutters 146, are mounted on the bottom end of the earth boring device 120, the cutters being attached to pistons of a servomotor 148 for extension to the position shown in which the outer ends of the cutters 146 project beyond the well casing, and for retraction to a position in which the outer ends of the cutters 146 are within the path of movement of the well casing, for a purpose to be explained hereinafter. The servomotor is mounted on a support 150 attached to the lower end of the cylindrical side wall 128, the support having radially disposed slots 152 through which operating rods 153, connecting the cutters 146 with the pistons of the servomotor, are guided.

At its midpoint, the support 150 carries an auger 154 to center and stabilize the movement of the earth boring device, and to break any rock formation that may be encountered.

A plurality of earth excavation means 156, 158 and 160 are mounted for rotation on radially disposed shafts below the bottom wall 130 and above the support 150. Radially disposed

rock crushers

164 and 166 are also mounted for rotation on shafts between the bottom wall 130 and the support 150. Each of the excavating means 156, 158 and 160, and the

rock crushers

164 and 166, is driven by a sprocket and chain drive by a separate motor 168 located within the hollow housing 124. The motors 168 may be of any well known type, operated by electricity or by a fluid under pressure.

The excavating means 156 has a plurality of radially disposed cutting blades 170; the excavating means 160 includes a plurality of angularly disposed cutting blades 172; and the excavating means 158 includes a plurality of curved cutting blades 174. The rock crushers 164 include a plurality of steel balls 176 attached to flexible rods, and the rock crushers 166 include a plurality of steel balls 180 supported on the ends of helical spring mountings 182.

A plurality of jets 184 are mounted within the tubular member 134.

In operation, the earth boring device 120 is lowered into the well casing 122, the cutters 146 being in their retracted position. The external flange 138 has a smaller diameter than the diameter of the teeth on the ring gear 140 so that, in lowering the earth boring device, the flange 138 can pass through the teeth of the ring gear until it comes to rest on the upper surface of the internal flange 136. In this position the lower end of the hollow housing 124 is disposed below the lower end of the well casing 122, and by actuating the servomotor 148 the cutters 146 can be extended to a position to cut an annular channel below the well casing 122 when the motor 144 is actuated to cause rotation of the earth boring device. At the same time, the motors 168 are energized to produce rotation of the excavating means 156, 158 and and the

rock crushers

164 and 166. The excavated detritus is forced upwardly through the cone-shaped member 132 and the fluid discharged through the jets 184 carry the detritus upwardly through the tubular member 134 to a discharge point on the surface of the ground.

As the earth boring device rotates the cutters 146 describe a helical path below the well casing 122, and there will alwyas be a shelf of unexcavated earth below the well casing above the level of the cutters to support the well casing and prevent it from interfering with the operation of the cutters.

While only one pair of diametrically disposed cutters is disclosed, it is evident that more than one pair may be used. The excavating means 156, 158 and 160, and the

rock crushers

164 and 166 could be removably mounted, so that it is possible to interchange any type of excavating means or rock crushers, depending on the nature of the formation to be excavated.

The well casing 122 and the tubular member 134 may be made in sections of appropriate length, so that additional sections can be attached as the depth of the bore increases.

FIGS. 12-17, inclusive, illustrate a fourth embodiment of the invention, in which a different form of cutting means is employed.

Referring to FIG. 12, the earth boring device is designated in its entirety by the numeral 200, and is operable within a well casing 202.

The earth boring device 200 comprises a hollow housing 204 having an upper deck 206, a cylindrical side wall 208 and a bottom wall 210, the latter merging, at its center, into a cone-shaped member 212 communicating at its apex with a vertically extending tubular member 214 passing upwardly through the housing 204 and the well casing 202 to a point above the surface of the ground being excavated (not shown) for the discharge of detritus removed from the well bore.

At a point above the bottom, the well casing includes an internal flange 216 adapted to support an external flange 218 formed integrally with the side wall 208 of the hollow housing 204 to limit the downward movement of the earth boring device as in the previously described embodiments. Above the internal flange 216 and at a position slightly above the upper deck 206 of the housing 204, the internal wall of the wall casing 202 is provided with an internal ring gear 220 adapted to mesh with the teeth of the gear 222 of a pinion means driven by a motor 224 disposed within the hollow housing 204. A pair of motor driven gears 222, diametrically disposed, produce rotation of the earth boring device when the motors 224 are actuated. The motors may be electrically or fluid actuated and controlled above the surface of the ground in an obvious manner forming no part of the present invention.

A pair of diametrically disposed cutting means 226 is supported at the lower end of the housing 204, each cutting means including a housing 228 having a pair of

lugs

230 and 232, the lug 230 being pivotally mounted at 234 to the lower end of the housing 204, and the lug 232 being pivotally connected with one end of a piston rod 240 of a servomotor 238 mounted within the hollow housing 204, the piston rod extending through a slot 242 in the bottom wall 210.

As seen in FIGS. and 16, the housing 228 is cylindrical and extends circumferentially more than l80, including, at one end, a bearing 244 for a cutter shaft 246 supporting a plurality of helical cutters 254 which extend, when the cutting means is disposed in its extended position as shown in FIG. 15, to a position below the well casing 202.

A pinion 248 is secured by welds 249 to the outer edge of the cutters 254 in line with a ring gear 252 on the bottom end of the well casing 202 to mesh therewith when the cutting means occupies its extended position shown. As shown in FIG. 14, the pinion 248 is provided on one side with a slot forming a bearing surface 250 to cooperate with the end of the housing 228.

The housing 228 also includes a plurality of

slots

253 and 255 for the discharge of detritus from the housing 228 enclosing the cutters 254.

Additional excavating means 256 extend diametrically across the lower end of the housing 204, which support an auger 258 at its midpoint.

The interior of the tubular member 214 is provided, at spaced points along its length, with a plurality of jets 260 to remove detritus to a point above the surface of the ground.

The earth boring device 200 and the well casing 202 are lowered in the same manner as described with reference to the other embodiments, sections of the well casing and tubular member 204 being added as the depth of the bore increases, in an obvious manner. In order to raise or lower the earth boring device, the servomotors 238 areactuated to pivot the inner ends of the cutting means 226 upwardly to swing the outer ends thereof to a position within the line of the well casing, so that when raised or lowered, the cutting means 226 will clear the internal ring gear 220, the internal flange 216 and the ring gear 252. When in its lowered position, the external flange 218 will rest on the internal flange 216, and the gear 222 will mesh with the teeth of the internal ring gear 220. The servomotors 238 can then be actuated to bring the inner end of the cutting means 226 to the position shown in FIG. 12, in which position the teeth of the pinion 248 will mesh with the fixed teeth on the ring gear 252, the outer end of the helical cutters will extend below the well casing 202 as shown. Actuation of the motors 224 will cause rotation of the earth boring device 200 within the well casing 202, and also rotation of the helical cutters 254 and the excavating means 256. The cutters 254, in their revolving movement about the axis of the housing 204, will cut helical channels as they proceed downwardly, always leaving a ridge of uncut earth above the level of the cutters to support the well casing 202, so that that it will not be necessary for the cutters to support the entire weight of the well casing. The detritus from the cutters is moved toward the center of the housing 228 and discharged through the

slots

253 and 255 in the housing and commingle with the detritus cut by the excavating means 256. and discharged to the surface by means of the jets 260 through the tubular member 214. The auger 258 is effective to break through rock formation and to serve to center the earth boring device and well casing.

A fifth embodiment of the invention, illustrating a different arrangement of cutting means, is shown in FIG. 18-22, inclusive. Referring to FIGS. 18 and 19, the earth boring device is designated in its entirety by the numeral 270, and is shown in its operating position within a well casing 272. The earth boring device comprises a hollow housing 274 having an upper deck 276 and a cylindrical side wall 278, the lower end of which is connected with the base end of a cone-shaped member 280. The apex of the cone-shaped member 280 merges into a tubular member 282 passing upwardly through the hollow housing 274 and upper deck 276 to terminate above the surface of the earth for the discharge of the detritus as will be described more fully hereinafter.

The well casing 272 carries an internal flange 284 adapted to support an external flange 286 on the upper deck 276. Secured to the inner wall of the wall casing 272, or formed integrally therewith, is an internal ring gear 288 adapted to be engaged by the teeth of a gear or pinion means 290 driven by a motor 292 mounted within the interior of the hollow housing 274. Actuation of the motor 292 will product rotation of the earth boring device 270 in an obvious manner. As illustrated, a pair of diametrically disposed motor driven pinion means 290 are disclosed, but it is obvious that one, or more than two, may be employed. The diameter of the flange 286 is less than the diameter of the ring of gear teeth of the internal ring gear 288, and greater than the diameter of the internal flange 284, so that the earth boring device 270 can be raised and lowered within the well casing 272, and when lowered, the flange 286 comes to rest on the upper surface of the flange 284 with the pinion means or gear 290 meshing with the teeth of the internal ring gear 288 and all other operating parts in the desired position within the well casing. As in the previously described embodiments, the motors 292 may be operated electrically or by a fluid under pressure.

Supported from the lower wall of the cone-shaped member 280 by means of a plurality of supporting members is a pair of diametrically disposed cutting means 294, below the bottom end of the earth boring device 270 and substantially in line with the lower end of the well casing 272.

Each of the cutting means 294 includes three radially disposed cutters 296, each cutter supported at one end by an angular arm 298 secured to a connecting member 300 carrying a pair of wheels or rollers 302 operating within a circular guide 304 which is C-shaped in cross section.

Referring to FIGS. 18, 20 and 22, the circular guide 304 extends around the internal wall of the well casing 272, being formed integrally with the lower end thereof, and includes a slot 306 through which the arms 298 extend. Diametrically disposed sections of the circular guide 304 are widened in horizontal cross section,

as shown at 208 in FIG. 21, to form an enlarged opening 312 sufficiently large to accommodate the passage of the connecting member 300 and the rollers 302 when it is desired to retract the cutters as explained hereinafter.

Piston rods 314 are attached to the arms 298 of the two end cutters 296 of each group of cutting means 294, each piston rod being attached to be operated by the piston of a servomotor 316. The connecting member 300 for the middle cutter 296 is attached, by a pair of flexible connecting links such as chains 310, to the two connecting members 300 on either side, so that rotation of the connecting members 300 for the two end cutters will carry along the middle cutter.

The supporting member 318 also supports a plurality of radially extending excavating means 320, and an auger 322. If desired, the cutters 296 and the excavating means may be curved and/or disposed at an angle to the radius to force the excavated detritus toward the center and up through the cone-shaped member whence it is ejected to a point above the surface of the ground by the force of a fluid discharged through the jets 324 at spaced intervals in the tubular member 282.

It should be noted that the cutters 296, when in their extended and operating position as shown, cut a channel below the well casing 272 when the earth boring device 270 is caused to rotate by the actuation of the motors 292. Since the channels cut by the cutters 296 are helical, there will always be a ridge of uncut earth, at a higher level than the channels cut by the cutters 296, to support the lower end of the well casing 272. The earth boring device 270 may be rotated in either direction, but it is preferred that it be rotated counterclockwise in FIG. 21.

When it is desired to retract the cutters 296 in order to raise the earth boring device, fluid pressure is admitted into the servomotors 318 to move the pistons therein in the direction which tends to retract the cutters, and at the same time rotate the earth boring device in a clockwise direction as seen in FIG. 21. When the rollers 302, operating within the guide 304, reach the widened section 308, the rollers will travel through the opening 312 and out of the guide 304, permitting total retraction of the cutters 296 into a position in which the earth boring device can be raised, permitting the cutters to clear the guide 304, internal flange 284 and internal ring gear 288 as it moves upwardly.

The well casing 272, as well as the tubular member 282, can be made in section of desired length, which may be connected as the depth of the bore being excavated increases, in an obvious manner.

In lowering the earth boring device 270 within the well casing, the cutting means will be in their retracted position. When the flange 286 of the earth boring device comes to rest on the flange 284, the parts are all in their proper position. The servomotors 316 are actuated to extend the cutting means 290 and at the same time the motors 292 are actuated to cause rotation of the earth boring device 270 in a counterclockwise direction as seen in FIG. 21, whereupon the connecting member 300 carrying the rollers 302 will enter the opening 312 and the guide 304, carrying the cutters 296 to their cutting position below the lower end of the well casing 272.

Although certain preferred embodiments of the invention have been herein described in order to illustrate the principles of the invention, it will be understood that certain modifications in structure can be effected without departing from these principles. Such modifications are therefore deemed to be circumscribed by the spirit and scope of the invention except as the same may be necessarily limited by the appended claims or reasonable equivalents thereof.

I claim:

1. An earth boring device for sinking a well casing, comprising: a housing having maximum external dimensions slightly less than the internal diameter of the well casing and rotatable therein; means carried by said housing and cooperable with other means carried by the well casing rotating said housing within the well casing; cutting means, circumferentially spaced relative to the well casing, excavating an annular bore below the well casing; means interconnecting said cutting means and said housing revolving said cutting means about said casing means excavating the material within the excavated annular bore; and means removing the detritus.

2. An earth boring device as defined in claim 1, including means carried by said rotatable housing retracting said cutting means from a position below the well casing and extending said cutting means to a position below the well casing.

3. An earth boring device as defined in claim 1, in which said cutting means are diametrically disposed.

4. An earth boring device as defined in claim 1, including a centrally disposed auger below said excavating means.

5. An earth boring device as defined in claim 1, in which said means rotating said housing within the well casing comprises a ring gear on the inner wall of the well casing, pinion means carried by said housing, engaging said ring gear, and a motor connected with and driving said pinion means.

6. An earth boring device as defined in claim 5, in which said housing is hollow, and in which said motor, rotating said housing, is disposed within said hollow housing.

7. An earth boring device as defined in claim 1, in which said means removing the detritus comprises a cone-shaped member within said housing, the larger diameter thereof disposed adjacent the means excavating the material within the excavated annular bore, and a tubular member connected with the apex of the coneshaped member and terminating a short distance above said housing, whereby the detritus is discharged and collected above said housing.

8. An earth boring device as defined in claim 7, including means forming a collector for detritus above said housing, said housing and said tubular member forming walls of said collector.

9. An earth boring device as defined in claim 1, in which said means excavating the bore within the excavated annular bore comprise a plurality of radially disposed, rotatable members, and motor means connected with and rotating said rotatable members.

10. An earth boring device as defined in claim 9, in which said housing is hollow, and in which said motor means, rotating said rotatable members, are disposed within said hollow housing.

11. An earth boring device as defined in claim 1, in which said circumferentially disposed cutting means comprise cutters on rotatable shafts mounted on the periphery of said housing, and motor means connected with and rotating said cutters.

12. An earth boring device as defined in claim 11, in which said cutters and motor means are mounted for radial movement, and means moving said cutters and motor means radially inward and outward.

13. An earth boring device as defined in claim 11, in which said housing is hollow, and in which said motor means, rotating said cutters, is disposed within said hollow housing.

14. An earth boring device as defined in claim 1, including an annular member secured to the lowe end of the well casing preventing said annular member from rotating; a track formed by said annular member; said cutting means mounted for revolving in said track.

15. An earth boring device as defined in claim 14, including means carried by said housing moving said cutting means radially inwardly and outwardly.

16. An earth boring device as defined in claim 15, in which said track includes an open portion permitting removal of and entry of the cutting means in response to simultaneous radial and revolving movement of said cutting means.

17. An earth boring device as defined in claim 1, in which said cutting means includes cutters, and means pivotally mounting said cutters on said housing for movement to and from a position below the well casing.

18. An earth boring device as defined in claim 17, including motor means connected with said cutters to move the latter from a position below the well casing to a position inwardly thereof, and vice versa.

19. An earth boring device as defined in claim 17, including an annular member secured to the lower end of the well casing, means forming an annular gear on the lower end of said annular member; means mounting said cutters for rotation and including a ring gear on each cutter engageable with said annular gear when said cutters are in position below the well casing.

20. An earth boring device as defined in claim 19, in which said cutters are extended inwardly from the lower end of the well casing toward the center of the bore formed by said boring device, said extensions forming said means excavating the material within the excavated annular bore.

' P0405) UNTKED STATES PATENT @FFICE (5/69) vi QERTWKQATE OF CORREQ'HQN Patent No. 2,835.9 LL2 Dated September 17, 197k Inrentofls) Samuel S; Leonardi It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line h3, the numeral "2O should read was:

Column 5, line 2 the numeral "30" should read 7O line 35, the word imatley should read imately line so, the numeral "9h", second occurrence, should read 92 0 r Column 6, line 9, the word "surfaces" should read surface v,- a

Column" 8, line 52, the word "wall" should read well Column '9, line 57, one occurrence of the word "that' should be deleted. 7

Column 10, line 23, the word product" should read produce line 58, the numeral "208" should read nup Column 12 line 9, the words "casing means" should read casing; means Column 13, line 2, the word "lowe should read lower Signed and sealed this 11th day of March 1975.

(SEAL) Attest:

, c MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks

Claims

7. An earth boring device as defined in claim 1, in which said means removing the detritus comprises a cone-shaped member within said housing, the larger diameter thereof disposed adjacent the means excavating the material within the excavated annular bore, and a tubular member connected with the apex of the cone-shaped member and terminating a short distance above said housing, whereby the detritus is discharged and collected above said housing.