Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
This invention relates to earth boring drill bits and,
more specifically, to rotary cone cu~ters for drilling wells
and blast holes.
Rotary cone cutters are construc~ed having mul~iple
rolling cutters on one end that rotate cooperating with one
another to reduce earth and hard rock formations. The individual
rolling cutters are mounted on multiple leg means that extend
rom, and are permanently at~ached to, the body of the drill bit.
In the manufacture o~ the drill bits~ rolling cutters are
mounted on the legs of the drill bit, usually using factory
methods and tools. The legs that carry the rolling cutters are
then assembled at the manufacturing plant, usually with the aid
of a special locating fixture, a~d permanently welded one to the
other and threaded.
The drill bits, when used in the field, are sub~ect to
extreme conditions of dirt, dust, shock and vibration such that
uneven wear or breakage can occur on the m~ltiple rolling
cutters. In many instances, one of the rolling cutters of the
drill bit may wear out or break in a short period of time,
while the other cutters remain in working condition.
Because each of the multiple cutters must cooperate when
drilling, the entire drill assembly becomes ineffective when one
of its multiple cutters breaks or becomes worn beyond a certain
point.
BRIEF SUMMARY OF THE INVENTION
According to the present invention, a rotary cone cutter
is constructed utilizing a pot member which ~as one end for
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attac~nent to a drill string. On another end of the po~, a
recessed central portion is formed which is bounded by a
peripheral wall and a downwardly ~acing abutment surface.
Legs having rolling cutters mounted thereon have an upper
part that comprises an upwardly facing abu~ment surface an an
upwardly extendlng attachmen~ region. Cooperating tongue and
groove or recess means are formed between the leg and pot as a
means for holding said legs nonrotational with said pot.
Means for releasably clamping the leg members to the pot
is provided in the form of a tapered plug that may be
reciprocably moved along the center line o the pot within the
recessed central portion. The ~apered plug holds the leg
members to the pot with the attachment region within the
recessed central por~ion and the abutment surfaces in con~ac~
with one another.
It is an object of the present invention to provide a
rotary cone cutter that can be partially disa~mbled in the
field to replace rolling cutters or a complete leg and cone
assembly when they become worn or broken.
It is a further object of the present inven~ion to reduce
~O the required inventory of spare rolling cutters that must be
kept on hand to supply the field drilling operations,
It is a further object of the present invention to provide
a rotary cone cutter with individual and releasable legs that
permit field changing of the legs.
The exact nature of the present invention will become more
clearly apparent upon reference to the following detailed specifi-
cation taken in connection with the accompanylng drawings in which:
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BRIEF DESCRIPTION OF THE DRA.WINGS
Figure 1 is a partially broken away side view of the
rotary cone cutter of the present mven-tion.
Figure 2 is an enlarged sectional view of the cutter of
Figure 1.
Figure 3 is a side view of the pot member used with the
present inven~ion.
Figure 4 is a bottom view of the pot member shown in
Figure 3.
Figure 5 is a view of a leg assembly according to the
present invention.
Figure 6 is a view through section VI-VI of Figure 2.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings somewhat more in detail, shown in
Figure 1 is a rotary cone cutter as~embly having a threaded end
12 that is adapted for attachment to the lower end of a drill
string. The rotary cone cutter 10 is shown comprised of a pot
member 14, a leg 16 and a roller cutter 18 mounted on one end of
the leg 16.
The leg member 16 has an upper part 19 for attachment to
the pot 14 and a plug member 20 is shown attached to a bolt 22
and, depending upon the direction of rotation of the bolt 22,
the plug member 20 is reciprocably advanceable along the center
line of the pot member 14.
The cutters 18, of course, have teeth 21 mounted thereon and
~he multiple rolling cutters 18 that are mounted on the multiple
independent leg means 16 cooperate with one another to reduce
earth and rock formations.
~ ~ ~ 3g ~ 3
Shown in greater detail in Figure 2 is the pot member 14
which has the threaded end 12 which is adapted for connection to
the lower end of a drill string. A pot member on its upper end
12 has a tubular passageway 24 designed to conduct flushing ~luid
from the drill s~ring through the rotary cone cutter to the
bottom oE the hole being drilled. Passageways 25 conduct the
fluid to the passageways 26 formed in the leg members~ The leg
members 16 are shown having a rolling cutter 18 mounted on the
one end and having an upper part 19 that joins with pot member 14
Passageways 21 conduct flushing fluid to the nozzles 23 for
washing the cuttings away from the hole bottom and up the bore,
outside the drill string.
Referring to Figure 3, showII therein is a side view of ~he
pot member 14. Pot member ~4 is again shown having the upper
end 12 and the lower end 30. The lower end 30 of the pot member
14 has slots 32 formed therein.
Referring to Figure 4, the bottom view of pot member 14 is
shown with the slots 32 bounded by a downwardly facing,
substantially horizontal, abutment surface 34 and air passages
26 extending through the downwardly Eacing, substantially
horizontal, abutment surfaces 34. Shown in the central part of
the pot member 14 is the recessed central portion 27 which is
bounded by a peripheral wall 28 and the downwardly Eacing,
substantially horizontal, abutment surfaces 34 on the side and
a bottom wall 29.
What is shown in Figure 5 is a leg assem~ly consisting oE
the rolling cutter 18 and leg member 16 Multiple leg members
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16 may be assembled with a single pot member so as to form a
rotary cone cutter, On top of leg member 16 is ~shown upper
part 19 which is comprised o-f an upwardly extending attachment
region 36 and an upwardly facing, substantially horizontal,
abutment sur~ace 38.
Reerring now to Figure 2, the upper part 19 is shown
having ~he upwardly extending attachment region 36 disposed in
the recessed cen~ral portion 27 of pot member 14. The leg 16
is held nonrotatable relative to the po~ member 14 in that a
cooperating tongue and groove joined as illustrated by 40 is
formed between the pot and the leg member.
The subs~antially horizontal abutment sùrfaces 38 and 34
are shown in contact with one ano~her and the tapered plug member
20 is shown in a clamped posi~ion. With the plug member 20
tightened and in a clamping position, the leg member is firmly
releasably secured to the pot member.
All that is necessary to remove an individual leg member
is to rotate the bolt 22 so as to advance the tapered plug
member 20 downwardly and enough so that the upper part 19 of the
leg member 16 can be pulled from the pot 14.
Modifications may be made within the scope of the appended
claims.
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