U.S. patent number 3,897,837 [Application Number 05/448,245] was granted by the patent office on 1975-08-05 for boring apparatus.
This patent grant is currently assigned to Rapidex, Inc.. Invention is credited to Carl R. Peterson.
United States Patent |
3,897,837 |
Peterson |
August 5, 1975 |
Boring apparatus
Abstract
Boring apparatus featuring a frame having a primary axis of
rotation and a flushing fluid inlet; and a plurality of
hole-enlarging assemblies mounted on the frame and having separate
axes of rotation radially outward of the primary axis; each
assembly having a working member rotatable about its respective
axis for acting upon the wall of the hole being bored, a flushing
fluid passage extending along the direction of the respective axis
to below the working member and communicating with the inlet, and a
nozzle in communication with the passage below the working member,
the nozzle having an orifice opening in a direction having at least
a component directed upwardly for directing flushing fluid upwardly
along the periphery of the working member, the working member
having a recess at least at one end with a thrust bearing in the
recess for effectively acting against the frame.
Inventors: |
Peterson; Carl R. (Boxford,
MA) |
Assignee: |
Rapidex, Inc. (Gloucester,
MA)
|
Family
ID: |
23779548 |
Appl.
No.: |
05/448,245 |
Filed: |
March 5, 1974 |
Current U.S.
Class: |
175/228; 175/347;
175/371; 175/340; 175/353; 175/374 |
Current CPC
Class: |
E21B
10/18 (20130101); E21B 10/25 (20130101); E21B
10/52 (20130101); E21B 10/30 (20130101); E21B
10/246 (20130101) |
Current International
Class: |
E21B
10/18 (20060101); E21B 10/30 (20060101); E21B
10/52 (20060101); E21B 10/24 (20060101); E21B
10/46 (20060101); E21B 10/22 (20060101); E21B
10/26 (20060101); E21B 10/08 (20060101); E21B
009/24 (); E21C 023/00 () |
Field of
Search: |
;175/334,335,339,340,344-348,353,359,371,374,382,228 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Brown; David H.
Claims
I claim:
1. Boring apparatus comprising
a frame having a primary axis of rotation and a flushing fluid
inlet, and
a plurality of hole-enlarging assemblies mounted on said frame and
having separate axes of rotation radially outward of said primary
axis, each said assembly having
a working member rotatable about its respective said axis of
rotation for acting upon the wall of the hole being bored,
means defining a flushing fluid passage extending along the
direction of said respective axis to below said working member and
communicating with said inlet, and
a nozzle in communication with said passage below said working
member, said nozzle having an orifice opening in a direction having
at least a component directed upwardly, for directing flushing
fluid upwardly along the periphery of said working member.
2. The apparatus of claim 1 further comprising a wall of said frame
spaced above said working members, and a nozzle member in said wall
and communicating with said inlet, said nozzle member having
nozzles directed toward the space between said wall and said
working members.
3. The apparatus of claim 1 wherein said passage is defined within
the respective said working member.
4. The apparatus of claim 1 further comprising a pilot bit mounted
at the bottom of said frame, and means defining at least one
additional fluid flow passage communicating between said inlet and
said bit.
5. The apparatus of claim 4 wherein said frame comprises a
plurality of struts respectively located between said assemblies,
each said strut having, internally thereof, one of said additional
fluid flow passages communicating between said inlet and said
bit.
6. The apparatus of claim 1 wherein said nozzles are formed by said
frame and said working members.
7. The apparatus of claim 6 wherein said nozzles surround said axes
of said working members, and said frame includes annular inserts
for determining the orifice sizes of said nozzles.
8. The apparatus of claim 1 wherein each said assembly has a shaft
mounted in said frame, said working members being respectively
rotatable on said shafts, said passages respectively extending
within said shafts.
9. The apparatus of claim 8 wherein in each said assembly said
passage extends through the upper end of said shaft, an oblique
connector passage communicates between said fluid passage and said
inlet through a wall of said shaft, and a plug is mounted in the
upper end of said fluid passage, said plug including a metering
portion extending into the junction between said fluid and
connector passages, said plug being rotatable to vary the flow
cross-section through said junction.
10. The apparatus of claim 8 wherein the upper ends of said shafts
are in pressure communication with said inlet, lube passages are
provided in the walls of said shafts, and sealing pistons are
provided in said lube passages adjacent the upper ends of said
shaft.
11. The apparatus of claim 8 wherein said frame includes a threaded
portion defining said inlet and adapted for connection to a pipe
string, said shafts extend upwardly through said frame and having
portions radially outwardly of said threaded portion, and a
shaft-retaining collar is provided between the upper ends of said
shafts and said threaded portion, adapted to be held in place when
said pipe string is connected to said threaded portion.
12. The apparatus of claim 11 wherein, when said threaded portion
is connected to said pipe string, said collar provides a seal
against said frame radially outward of said shaft, and provides a
further seal against said pipe string.
13. The apparatus of claim 11 wherein said shafts and said collar
have cooperating flats to prevent rotation of said shafts.
14. The apparatus of claim 8 wherein each said working member has a
counterbore at its bottom end and a thrust bearing in said
counterbore for effectively acting against said frame.
15. The apparatus of claim 14 further comprising a thrust collar
insert in each said counterbore fixed against rotation relative to
said shaft, said thrust bearing acting against said frame through
said collar.
16. The apparatus of claim 6 wherein each said passage extends
below said collar, and radial openings in said shafts communicate
between said passages and said nozzles.
17. The apparatus of claim 6 further comprising seals between said
collars and said working members, flow of fluid from said passages
to said nozzles serving to keep said seals clean.
18. The apparatus of claim 8 wherein each said working member has a
counterbore at its upper end, and a thrust bearing in said
counterbore for effectively acting against said shaft to transfer
thrust via said shaft to said frame.
19. The apparatus of claim 18 further comprising a thrust shoulder
in each said counterbore in contact with said thrust bearing.
20. The apparatus of claim 19 wherein said shoulder is integral
with said shaft.
21. The apparatus of claim 19 wherein a seal is provided between
said shoulder and said working member.
22. The apparatus of claim 21 wherein said shoulder and said
working member define above said seal a chamber in communication
with said inlet and having a leakage outlet, whereby flow of fluid
through said chamber keeps said seal clean.
Description
BACKGROUND OF THE INVENTION
This invention relates to boring apparatus useful, e.g., in earth
or rock.
Typically such apparatus has a frame supported at the lower end of
a drill pipe string, with a pilot bit mounted at the bottom of the
frame and reamers for enlarging the pilot hole mounted on the frame
above the pilot bit.
SUMMARY OF THE INVENTION
The invention, in various aspects, provides compact (particularly
along the drilling axis), rugged, inexpensive apparatus capable of
efficient boring and chip removal. Improvements are provided in the
flow of flushing fluid to both the pilot bit and the enlarging
members, as well as in lubrication and protection of the bearing
systems in the hole-enlarging assemblies.
In general the invention features, in one aspect, a frame having a
primary axis of rotation and a flushing fluid inlet; and a
plurality of hole-enlarging assemblies mounted on the frame and
having separate axes of rotation radially outward of the primary
axis; each assembly having a working member rotatable about its
respective axis for acting upon the wall of the hole being bored, a
flushing fluid passage extending along the direction of the
respective axis to below the working member and communicating with
the inlet, and a nozzle in communication with the passage below the
working member, the nozzle having an orifice opening in a direction
having at least a component directed upwardly for directing
flushing fluid upwardly along the periphery of the working member.
In another aspect the invention features frame-mounted
hole-enlarging assemblies each having a shaft fixed to the frame, a
working member rotatable on the shaft about its respective axis of
rotation for acting upon the wall of the hole being bored, the
working member having a recess at least at one end, and a thrust
bearing in the recess for effectively acting against the frame. In
preferred embodiments a pilot bit is mounted at the bottom of the
frame; frame struts and hole-enlarging cutters are arranged
alternately around the primary axis of rotation of the frame, with
flushing fluid being supplied to the pilot bit through the struts
and to the cutters through the cutter shafts; the nozzles are
formed between the frame and the cutter bodies; a thrust shoulder
and a thrust collar are provided in cutter body counterbores; seals
between the thrust shoulder and collar and the cutter bodies are
kept clean by the flow of flushing fluid outwardly adjacent those
seals; the frame includes annular inserts for determining the
orifice sizes of the nozzles; rotatable plugs are arranged in the
upper ends of the cutter shaft fluid passages to control the flow
cross-sections between the flushing fluid inlet and the shaft
passages; and an annular collar, held against the frame by the pipe
string, is provided to prevent cutter shaft rotation and to seal
the flushing fluid manifold at the upper end of the frame. In some
embodiments the upper thrust shoulders are integral with the cutter
shafts. The overall envelope of the apparatus tapers from top to
bottom, as does each cutter body.
Other advantages and features of the invention will be apparent
from the description and drawings herein of a preferred embodiment
thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation of apparatus embodying the invention,
connected to a fragment of a pipe string;
FIG. 2 is a view similar to FIG. 1, from a different angle, with
the pipe string and pilot bit omitted;
FIG. 3 is an enlarged view of a portion of FIG. 1, partially in
section;
FIGS. 4-8 are sectional views taken respectively along 4--4, 5--5,
6--6, 7--7, and 8-8 of FIG. 1; and
FIG. 9 is a sectional view taken along 9--9 of FIG. 3 with the
cutter shafts removed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, there is shown a main frame 10 connected
at its top through externally threaded connector 12 to pipe string
14 which extends back to the surface drill rig, and at its bottom
through internally threaded connector 16 to conventional tricone
pilot bit 18. Frame 10 tapers from top to bottom along three
circumferentially spaced struts 20 extending between upper and
lower frame portions 22 and 24. Three cutters 26, 28, and 30 are
respectively arranged between struts 20.
Each cutter has tooth inserts 32 in a body 33 mounted to rotate
about shaft 34 (FIG. 3) having an axis 35 which not only generally
follows the taper of struts 20 but is also skewed (e.g., by
2.degree.-4.degree., FIG. 2) with respect to the vertical axis 36
of frame 10. In overall operation rotation of frame 1 causes
cutters 26, 28, and 30 to rotate and to enlarge the pilot hole
produced by bit 18. The skew of the cutters produces vertical force
components between the hole wall and the cutters, causing the
apparatus to be at least partially self-advancing.
Body 33 is tapered where it receives inserts 32, and has fixed to
itself in counterbores 40 and 42 annular upper and lower thrust
bearings 44 and 46 and, on the inside cylindrical surface of its
central bore 48, axially spaced radial bearing inserts 50 and 52.
The upper bearing 44 runs against enlarged upper portion 54 of
shaft 34, which acts as a thrust shoulder integral with the shaft.
Lower thrust bearing 46 runs against a thrust collar 55 inserted in
cutter body counterbore 42 and pinned (not shown) to the shaft to
prevent rotation of the collar about the shaft while allowing
relative axial movement between collar and shaft. O-rings 62 and 64
respectively provide the primary dynamic seals between stationary
collar 54 and collar 55 and the rotating cutter body. Static seal
70 is provided between the collar 55 and shaft 34, to keep dirt out
of the internal system and to hold lubricant in. The location of
the shoulder and thrust collar within counterbores in the ends of
the cutter bodies minimizes the overall length of the assembly,
including the length of the struts and shafts, thereby increasing
strength.
The lower ends of shafts 34 extend into cylindrical bores 80 in
frame portion 24. The upper shaft ends are notched at 82 (and at
82', to allow for 180.degree. rotation of the shaft after wear) to
receive generally annular retainer collar 84, which holds all three
shafts in place and prevents them from rotating. In particular,
collar 84 has three pockets 86 (FIG. 4) to receive the notched
shaft ends, collar surfaces 88 acting against the shaft flats to
prevent shaft rotation. Collar 84 is press fitted around frame
portion 22 just below connector 12. Threaded pipe string portion 92
screwed on connector 12 acts as a hold down, pressing collar 84
against the shafts and frame portion 22.
Provision is made for supplying flushing fluid (e.g., air, clear
water, or mud, etc.) to pilot bit 18 and to cutters 26, 28, and 30,
to flush the rock removed during the drilling process. Thus, axial
fluid inlet passage 100 communicates with a diagonal inlet 104 in
each shaft 34 and an axial passage 106 in each strut 20. (Each
shaft 34 has a second inlet 104' for use when the shaft is
rotated.) Inlet 104 in turn feeds axial passage 108 within the
shaft. Passages 108 dead end at the bottoms of the shafts. Plug 110
(FIG. 3) fits (without sealing) in the top of passage 108, and is
cut off obliquely at its lower end extending into inlet 104.
Rotation of the plug changes the effective flow cross-section
between inlet 104 and passage 108, thus metering the rate of fluid
flow to passage 108. Cap 112 on plug 110 can be indented into
recess 114 in the end of shaft 34 to fix the angular position of
the plug once it has been adjusted. Collar 84 seals against the
pipe string at 116 and against the frame at 118 to prevent leakage
of flushing fluid to the atmosphere.
Passage 108 communicates in the region of thrust shoulder 54,
through radial holes 120 in shaft 34, with generally annular buffer
chamber 122 formed in the outer surface of the shoulder, just above
seal 62. A narrow clearance 124 (e.g., 0.005 inch radially) is
provided between shoulder 54 and cutter body 33, communicating with
chamber 122 and thus providing for a continuous small escape of
fluid from the buffer chamber, so that clean fluid is always kept
outside seal 62, despite the dirty environment in which the
apparatus operates.
Just below thrust collar 55 passage 108 communicates, through
radial holes 130 in shaft 34 and aligned radial slots 132 (FIG. 9)
in the frame below shoulder 60, with annular buffer chamber 134.
Relatively large clearance 136 (e.g., 0.02 inch) is provided
between cutter body 33 and frame portion 24, so that a substantial
amount of fluid flows through chamber 134 and upwardly past teeth
32. Not only is clean fluid thus kept outside of seal 64, but the
cutter is cooled, the conical portion of the hole being drilled is
flushed, and the jet pump effect of the upwardly flowing fluid
helps to draw upwardly further chips and fluid from the region of
the pilot bit. To precisely control the size of clearance 136
(which thus acts as a nozzle), replaceable split ring insert 138
fits in frame portion 24, surrounding (but spaced from) cutter body
33. Flange 140 of ring 138 fits in frame slot 142. The thickness of
ring 138 thus determines the nozzle width. The relative rotation
between the opposing nozzle-defining walls of clearance 136 gives
the nozzle an advantageous self-cleaning quality in use.
Collar 84 seals the tops of strut passages 106, which at their
other ends communicate with lower plenum 150. Plenum 150 in turn
communicates with axial passage 152 (FIG. 1) and, through that
passage, with conventional flushing jets 154 in pilot bit 18. Bores
80 communicate through reduced diameter extensions 80a with plenum
150, simply to provide access to the bottoms of shafts 34 (e.g.,
with a push rod) for disassembly. Shafts 34 rest against shoulders
80b to prevent fluid communication between bores 80 proper and
plenum 150.
A removable jet fitting 160 extends axially through the bottom wall
162 of plenum 102. The fitting has an axial orifice 164 to project
a jet of flushing fluid down the center of frame 10, adjacent the
three cutters 26, and three radial orifices 166 to flush between
frame wall 162 and the tops of the cutters.
A system for distribution of pressurized lubricant (e.g., grease)
is also provided. A grease reservoir 170 (FIG. 3) extends in the
wall of each shaft 34, parallel to passage 108. A movable pressure
piston 172 is located at the upper end of each reservoir 170, with
O-ring 174 providing a seal between the piston and the inner wall
of the reservoir. Flushing fluid communicates with the top of
piston 172 to pressurize the grease in the reservoir at the
flushing fluid pressure. Lube passage 176 extends down from the
reservoir, and provides grease through holes 178 to lube grooves
180 at opposite sides of the shaft 34. Grooves 180 may be provided
by flats on shaft 34, or may be of any other suitable shape. From
grooves 180 the lubricant moves along the outside of the shaft to
feed the thrust and radial bearing areas. Seal 70 isolates the
lubricant from the atmosphere.
As shown in FIG. 8, upper and lower portions 22 and 24 of frame 10
are of reduced diameter between the positions of the three cutter
shafts 34, thus providing, in effect, recesses along which can flow
rock cuttings produced by the drilling process. Carbide inserts 200
in the frame periphery at portions 22 and 24 protect the frame
against wear.
Other embodiments are within the following claims:
* * * * *